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Câmara SPA, Dapkevicius A, Silva CCG, Malcata FX, L. N. Enes Dapkevicius M. Artisanal Pico cheese as reservoir of Enterococcus species possessing virulence and antibiotic resistance properties: implications for food safety. FOOD BIOTECHNOL 2020. [DOI: 10.1080/08905436.2019.1710844] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- S. P. A. Câmara
- Food Technology Group, Institute of Agricultural and Environmental Research and Technology (IITA-A), University of the Azores, Angra do Heroísmo, Portugal
- Faculty of Agricultural and Environmental Sciences, University of the Azores, Angra do Heroísmo, Portugal
| | - A. Dapkevicius
- Food Technology Group, Institute of Agricultural and Environmental Research and Technology (IITA-A), University of the Azores, Angra do Heroísmo, Portugal
- Higher School for Technologies, University of the Azores, Angra do Heroísmo, Portugal
| | - C. C. G. Silva
- Food Technology Group, Institute of Agricultural and Environmental Research and Technology (IITA-A), University of the Azores, Angra do Heroísmo, Portugal
- Faculty of Agricultural and Environmental Sciences, University of the Azores, Angra do Heroísmo, Portugal
| | - F. X. Malcata
- Department of Chemical Engineering, University of Porto, Oporto, Portugal
- LEPABE Laboratory of Process Engineering, Environment, Biotechnology and Energy, College of Engineering, University of Porto, Porto, Portugal
| | - Maria L. N. Enes Dapkevicius
- Food Technology Group, Institute of Agricultural and Environmental Research and Technology (IITA-A), University of the Azores, Angra do Heroísmo, Portugal
- Faculty of Agricultural and Environmental Sciences, University of the Azores, Angra do Heroísmo, Portugal
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Câmara SP, Dapkevicius A, Riquelme C, Elias RB, Silva C, Malcata FX, Dapkevicius M. Potential of lactic acid bacteria from Pico cheese for starter culture development. FOOD SCI TECHNOL INT 2019; 25:303-317. [PMID: 30646760 DOI: 10.1177/1082013218823129] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Autochthonous lactic acid bacteria may provide a means of promoting the quality and safety of traditional fermented food products, in particular, artisanal cheeses. Pico cheese is an artisanal, dairy specialty of the Azores in risk of disappearing. Efforts to maintain its quality to the requirements of the modern markets are, thus, necessary. Lactic acid bacteria were isolated from artisanal Pico cheese, identified by sequencing of the 16S rRNA gene, and their potential as starter cultures was evaluated by studying their acidification ability, enzymatic activities (caseinolysis, lipolysis and API-ZYM profile), diacetyl and expolysaccharide production, autolysis, antimicrobial activity against Listeria monocytogenes ATCC 7466, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29523, Pseudomonas aeruginosa ATCC 27853 and Clostridium perfringens ATCC 8357, sensory evaluation of odour formation in milk, syneresis and firmness of the curd. Several of the studied lactic acid bacteria isolates showed interesting properties for practical application as starters in artisanal cheese production. The isolates with the highest number of positive traits and, therefore, the most promising for starter development were Lactococcus lactis ssp. lactis L1C21M1, Lactobacillus paracasei L1B1E3, Leuconostoc pseudomesenteroides L1C1E6, Lactobacillus casei L1A1E5 and L1C1E8.
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Affiliation(s)
- S P Câmara
- 1 Food Technology Group, Institute of Agricultural and Environmental Research and Technology (IITA-A), University of the Azores, Pico da Urze, Angra do Heroísmo, Portugal.,2 Faculty of Agricultural and Environmental Sciences, University of the Azores, Pico da Urze, Angra do Heroísmo, Portugal
| | - A Dapkevicius
- 1 Food Technology Group, Institute of Agricultural and Environmental Research and Technology (IITA-A), University of the Azores, Pico da Urze, Angra do Heroísmo, Portugal.,3 Higher School of Technologies, University of the Azores, Pico da Urze, Angra do Heroísmo, Portugal
| | - C Riquelme
- 1 Food Technology Group, Institute of Agricultural and Environmental Research and Technology (IITA-A), University of the Azores, Pico da Urze, Angra do Heroísmo, Portugal
| | - R B Elias
- 2 Faculty of Agricultural and Environmental Sciences, University of the Azores, Pico da Urze, Angra do Heroísmo, Portugal.,4 CE3C - Centre for Ecology, Evolution and Environmental Changes/Azorean Biodiversity Group and University of the Azores, Pico da Urze, Angra do Heroísmo, Portugal
| | - Ccg Silva
- 1 Food Technology Group, Institute of Agricultural and Environmental Research and Technology (IITA-A), University of the Azores, Pico da Urze, Angra do Heroísmo, Portugal.,2 Faculty of Agricultural and Environmental Sciences, University of the Azores, Pico da Urze, Angra do Heroísmo, Portugal
| | - F X Malcata
- 5 LEPABE/Department of Chemical Engineering, University of Porto, Oporto, Portugal
| | - Mlne Dapkevicius
- 1 Food Technology Group, Institute of Agricultural and Environmental Research and Technology (IITA-A), University of the Azores, Pico da Urze, Angra do Heroísmo, Portugal.,2 Faculty of Agricultural and Environmental Sciences, University of the Azores, Pico da Urze, Angra do Heroísmo, Portugal
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Abstract
In whey cheese manufacture, whey, plain or added with milk, is heated by direct fire, bubbling steam or alternatively in jacketed vats. In some cases, salt s or organic acids are previously added. At 80-85 OC, the first particles of curd form; at 85-95 'C, the curd may be cooked for a few minutes to reduce moisture content and/or to obtain the desirable level of browning. After drainage at room temperature during molding for ca. 4 h, whey cheese is stored at ca. 4 'C. The typical mass yield is 6%, but addition of milk, calcium salts and preliminary concentration of protein (by condensation or ultrafiltration techniques) may increase yield considerably. Some types of whey cheeses are supposed to be consumed within a short time upon manufacture (e.g., Ricotta, Requeijdo and Manouri), whereas others bear a longer shelf life (e.g., Gjetost, Mysost and Myzithra). Whey cheeses are significantly different from one another in terms of chemical composition, which is mainly due to variations in the source and type of whey, as well as to the processing practices followed. Moisture content and pH of whey cheeses are usually high and favor microorganism growth (molds, yeasts, lactic acid bacteria and Enterobacteriaceae account for the dominant microflora in these cheeses). Adequate packaging of whey cheeses should be provided, and legislation should be prepared to fix standard characteristics of each type of whey cheese, and hence protect typical products from adulteration and fakes. Marketing efforts should also be aimed at increasing whey cheese consumption, either directly or incorporated in desserts, snack dips and pasta-type dishes.
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Affiliation(s)
- M. E. Pintado
- Escola Superior de Biotecnologia, Universidade Cat6lica Portuguesa, Rua Dr. Antonio Bernardino de Almeida, P-4200-072 Porto, Portugal
| | - A. C. Macedo
- Escola Superior de Biotecnologia, Universidade Cat6lica Portuguesa, Rua Dr. Antonio Bernardino de Almeida, P-4200-072 Porto, Portugal; Instituto Superior da Maia, Avenida Carlos Oliveira Campos, Castelo da Maia, 4470 Maia, Portugal
| | - F. X. Malcata
- Escola Superior de Biotecnologia, Universidade Cat6lica Portuguesa, Rua Dr. Antonio Bernardino de Almeida, P-4200-072 Porto, Portugal
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Ramos ÓL, Pereira JO, Silva SI, Fernandes JC, Franco MI, Lopes-da-Silva JA, Pintado ME, Malcata FX. Evaluation of antimicrobial edible coatings from a whey protein isolate base to improve the shelf life of cheese. J Dairy Sci 2012; 95:6282-92. [PMID: 22939797 DOI: 10.3168/jds.2012-5478] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 06/28/2012] [Indexed: 11/19/2022]
Abstract
The objective of this work was to evaluate the effectiveness of antimicrobial edible coatings to wrap cheeses, throughout 60 d of storage, as an alternative to commercial nonedible coatings. Coatings were prepared using whey protein isolate, glycerol, guar gum, sunflower oil, and Tween 20 as a base matrix, together with several combinations of antimicrobial compounds-natamycin and lactic acid, natamycin and chitooligosaccharides (COS), and natamycin, lactic acid, and COS. Application of coating on cheese decreased water loss (~10%, wt/wt), hardness, and color change; however, salt and fat contents were not significantly affected. Moreover, the antimicrobial edible coatings did not permit growth of pathogenic or contaminant microorganisms, while allowing regular growth of lactic acid bacteria throughout storage. Commercial nonedible coatings inhibited only yeasts and molds. The antimicrobial edible coating containing natamycin and lactic acid was the best in sensory terms. Because these antimicrobial coatings are manufactured from food-grade materials, they can be consumed as an integral part of cheese, which represents a competitive advantage over nonedible coatings.
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Affiliation(s)
- Ó L Ramos
- CBQF/Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, P-4200-072 Porto, Portugal
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Tavaria FK, Soares JC, Reis IL, Paulo MH, Malcata FX, Pintado ME. Chitosan: antimicrobial action upon staphylococci after impregnation onto cotton fabric. J Appl Microbiol 2012; 112:1034-41. [PMID: 22380634 DOI: 10.1111/j.1365-2672.2012.05274.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND High levels of viable Staphylococcus aureus, which are often found on inflamed skin surfaces, are usually associated with atopic dermatitis. Textiles, owing to their high specific surface area and intrinsic hydrophilicity, retain moisture while also providing excellent environmental conditions for microbial growth and proliferation. Recently, a number of chemicals have been added to textiles, so as to confer antimicrobial activity. AIMS To evaluate the antimicrobial action of chitosan upon selected skin staphylococci. METHODS AND RESULTS We isolated staphylococci from normal skin of 24 volunteers and studied their survival upon contact with chitosan-impregnated cotton fabric. Low and high molecular weight chitosans were used at two concentrations; all four did effectively reduce the growth of some staphylococci (namely Staph. aureus), by up to 5 log cycles, thus unfolding a potential towards control and even prevention of related skin disorders. CONCLUSION Our data suggest an effective, but selective antibacterial action of chitosans towards skin bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY The possibility to use a natural biopolymer incorporated in a textile to alleviate and even treat some of the symptoms associated with this skin condition may raise an alternative to existing medical treatments. The selectivity observed prevents full elimination of bacteria from the skin surface, which is an advantage.
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Affiliation(s)
- F K Tavaria
- Centro de Biologia e Química Fina (CBQF), Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto, Portugal
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Rocha JM, Kalo PJ, Malcata FX. Neutral Lipids in Free, Bound, and Starch Lipid Extracts of Flours, Sourdough, and Portuguese Sourdough Bread Determined by NP-HPLC-ELSD. Cereal Chem 2011. [DOI: 10.1094/cchem-11-10-0157] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- J. M. Rocha
- CBQF/Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, P-4200-072 Porto, Portugal
- Department of Applied Chemistry and Microbiology, P. O. Box 27 (Latokartanonkaari 11), FIN-00014 University of Helsinki, Finland
- Instituto Superior de Agronomia, Universidade Técnica de Lisboa, Tapada da Ajuda, P-1349-017 Lisboa, Portugal
| | - P. J. Kalo
- Department of Applied Chemistry and Microbiology, P. O. Box 27 (Latokartanonkaari 11), FIN-00014 University of Helsinki, Finland
| | - F. X. Malcata
- Instituto Superior da Maia, Avenida Carlos Oliveira Campos, P-4475-690 Avioso S. Pedro, Portugal
- CEBAL—Centro de Biotecnologia Agrícola e Agro-alimentar do Baixo Alentejo e Litoral, Rua Cidade de S. Paulo, Apartado 6158, P-7801-908 Beja, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida da República, P-2780-157 Oeiras, Portugal
- Corresponding author. Instituto Superior da Maia, Avenida Carlos Oliveira Campos, P-4475-690 Avioso S. Pedro, Portugal. Phone: (+351) 968 017 411. Fax: (+351) 229 825 331. E-mail:
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Gião MS, Pestana D, Faria A, Guimarães JT, Pintado ME, Calhau C, Azevedo I, Malcata FX. Effects of extracts of selected medicinal plants upon hepatic oxidative stress. J Med Food 2010; 13:131-6. [PMID: 20136446 DOI: 10.1089/jmf.2008.0323] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Aqueous extracts of a few medicinal plants traditionally used in Portugal have been assayed for their effects upon hepatic oxidative stress in mice. Previous in vitro studies had allowed characterization of agrimony, sage, savory, and raspberry in terms of overall antioxidant capacity and phenolic content. In the present study, the antioxidant effect and safety of these four plants were evaluated in vivo. For this purpose, mice ingested extracts in aqueous form (or water, used as the control) for 4 weeks; damage to lipids, proteins, and DNA was evaluated by oxidative cell biomarkers by the end of that period. Levels of hepatic glutathione and activities of enzymes involved in metabolism thereof were also determined. Finally, catalase and superoxide dismutase (SOD) activities were quantified, as these enzymes play a crucial role in antioxidant defense. When compared with the control, both raspberry and savory produced significant lipid protection; however, protein damage was significantly lower only in raspberry-treated animals. On the other hand, DNA damage was prevented only by savory. All plants led to a decrease in catalase activity, whereas all but sage also produced a decrease in SOD activity. With regard to glutathione levels and activities of enzymes involved in its metabolism, the aforementioned extracts exhibited different effects. In general, raspberry appeared to be the most promising extract, followed by savory, sage, and agrimony, sorted by decreasing performance in protection; the latter was even slightly toxic. Hence, the plants tested possess compounds with interesting biological activities that may support eventual inclusion in food or feed as functional additives.
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Affiliation(s)
- M S Gião
- CBQF/Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto, Portugal
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Madureira AR, Tavares T, Gomes AMP, Pintado ME, Malcata FX. Invited review: physiological properties of bioactive peptides obtained from whey proteins. J Dairy Sci 2010; 93:437-55. [PMID: 20105516 DOI: 10.3168/jds.2009-2566] [Citation(s) in RCA: 235] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 09/18/2009] [Indexed: 01/11/2023]
Abstract
Processing of whey proteins yields several bioactive peptides that can trigger physiological effects in the human body: on the nervous system via their opiate and ileum-contracting activities; on the cardiovascular system via their antithrombotic and antihypertensive activities; on the immune system via their antimicrobial and antiviral activities; and on the nutrition system via their digestibility and hypocholesterolemic effects. The specific physiological effects, as well the mechanisms by which they are achieved and the stabilities of the peptides obtained from various whey fractions during their gastrointestinal route, are specifically discussed in this review.
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Affiliation(s)
- A R Madureira
- Centro de Biotecnologia e Quimica Fina (CBQF)/Escola Superior de Biotecnologia, Universidade Católica Portuguesa, R. Dr. António Bernardino de Almeida, P-4200-072 Porto, Portugal
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9
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Abstract
The potential angiotensin-converting enzyme (ACE)-inhibitory and antioxidant activities of peptides in water-soluble extracts, obtained from raw and sterilized ovine and caprine cheeselike systems coagulated with enzymes from the plant Cynara cardunculus, were assessed. Prior to the assay, the 3,000-Da permeate from 45-d-old cheeselike systems was fractionated by tandem chromatographic techniques. Several peaks were obtained in each chromatogram, but only some were associated with ACE-inhibitory or antioxidant activity or both. Peptides Tyr-Gln-Glu-Pro, Val-Pro-Lys-Val-Lys, and Tyr-Gln-Glu-Pro-Val-Leu-Gly-Pro-* from beta-casein, as well as Arg-Pro-Lys and Arg-Pro-Lys-His-Pro-Ile-Lys-His-* from alpha(s1)-casein exhibited ACE-inhibitory activity. Peptides released upon cleavage of the peptide bond Leu190-Tyr191 (either in ovine or caprine beta-casein), and corresponding to the beta-casein sequence Tyr-Gln-Glu-Pro-*, possessed antioxidant activity.
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Affiliation(s)
- S V Silva
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, P-4200-072 Porto, Portugal
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Kongo JM, Ho AJ, Malcata FX, Wiedmann M. Characterization of dominant lactic acid bacteria isolated from São Jorge cheese, using biochemical and ribotyping methods. J Appl Microbiol 2008; 103:1838-44. [PMID: 17953594 DOI: 10.1111/j.1365-2672.2007.03423.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To identify, using phenotypic and genotypic methods, the dominant lactic acid bacteria (LAB) present in São Jorge cheese - one of the 11 Portuguese cheeses currently bearing an Appéllation d'Origine Protegée status. METHODS AND RESULTS A total of 225 isolates from milk, curd and cheeses throughout ripening were identified to the genus level, 108 to the species level and ten to the strain level. Phenotypic methods indicated that lactobacilli, followed by enterococci, were the dominant bacteria. The most frequently isolated species were Lactobacillus paracasei, Lactobacillus rhamnosus, Enterococcus faecalis and Enterococcus faecium. Ribotyping differentiated three L. paracasei, two E. faecalis and one Lactobacillus plantarum types. Enterococcus spp. exhibited the highest esterase and beta-galactosidase activities among all isolates. CONCLUSIONS The dominant LAB in São Jorge cheese are L. paracasei, L. rhamnosus, E. faecalis and E. faecium. Enterococcus likely plays a leading role upon acidification and aroma development in said cheese. SIGNIFICANCE AND IMPACT OF THE STUDY Our results support that a combination of conventional biochemical methods with genotypic methods allows for a thorough characterization and identification of isolates. Despite the limited number of isolates subject to molecular subtyping, a few specific Enterococcus and Lactobacillus strains were found that are promising ones for development of a starter culture. Hence, L. paracasei and E. faecalis are good candidates for a tentative starter culture, designed for manufacturing of São Jorge cheese at large - which takes advantage of actual isolates, in attempts to eventually standardize the quality of said cheese variety.
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Affiliation(s)
- J M Kongo
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, Porto, Portugal
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Abstract
Listeria monocytogenes is a foodborne pathogen that can cause serious invasive disease in humans. Because human listeriosis cases have previously been linked to consumption of contaminated cheese, control of this pathogen throughout the cheese production chain is of particular concern. To understand the potential for L. monocytogenes transmission via São Jorge cheese, a Portuguese artisanal cheese variety that bears a Protected Denomination of Origin classification, 357 raw milk, curd, natural whey starter, and cheese samples representative of the production chain of this cheese were collected over one year and tested for the presence of L. monocytogenes and selected physicochemical parameters. Although neither L. monocytogenes nor other Listeria spp. were detected in whey, curd, or cheese samples, 2 of the 105 raw milk samples analyzed were positive for L. monocytogenes. These 2 raw milk isolates represented a ribotype that has previously been linked to multiple human listeriosis outbreaks and cases elsewhere, indicating the potential of these isolates to cause human listeriosis. On average, physicochemical parameters of São Jorge cheese ripened for 4 mo presented values that likely minimize the risk of L. monocytogenes outgrowth during ripening and storage (mean pH = 5.48; mean moisture = 37.79%; mean NaCl concentration = 4.73%). However, some cheese samples evaluated in this study were characterized by physicochemical parameters that may allow growth and survival of L. monocytogenes. Even though our results indicate that raw milk used for São Jorge cheese manufacture as well as finished products is rarely contaminated with L. monocytogenes, continued efforts to control the presence of this pathogen in the São Jorge cheese production chain are urged and are critical to ensure the safety of this product.
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Affiliation(s)
- J M Kongo
- Centro de Investigação de Recursos Naturais, Departamento de Biologia, Universidade dos Açores, Ponta Delgada, Açores, Portugal
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Kongo JM, Gomes AM, Malcata FX. Manufacturing of fermented goat milk with a mixed starter culture of Bifidobacterium animalis and Lactobacillus acidophilus in a controlled bioreactor. Lett Appl Microbiol 2006; 42:595-9. [PMID: 16706898 DOI: 10.1111/j.1472-765x.2006.01882.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS This work was undertaken to study the feasibility and the characteristics of a fermented product made of goat milk, using a mixed starter culture of Bifidobacterium animalis and Lactobacillus acidophilus under controlled conditions, and to determine their survival in the fermented milk during refrigerated storage. METHODS AND RESULTS Goat milk was inoculated with Lact. acidophilus and Bif. animalis mixed starter, fermented in a glass bioreactor with controlled temperature (37 degrees C) and anaerobiosis, and monitored for growth and acidification. The fermented milk was then stored for 10 days under refrigeration, and monitored daily for starter microflora survival and pH changes. Lact. acidophilus viable counts reached a maximum of 7.1 x 10(8) colony-forming units (CFU) ml(-1), and Bif. animalis a maximum of 6.3 x 10(7) CFU ml(-1) by 20 h of fermentation. During refrigerated storage, both strains exhibited a good survival, with viable numbers remaining essentially constant throughout the experiment, whereas the pH of the fermented milk dropped slightly. CONCLUSIONS Mixed cultures of Bif. animalis and Lact. acidophilus may be used to produce fermented goat milk with high counts of both probiotic strains. SIGNIFICANCE AND IMPACT OF THE STUDY Goat milk fermented with Bif. animalis and Lact. acidophilus can be manufactured as an alternative probiotic dairy product.
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Affiliation(s)
- J M Kongo
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, Porto, Portugal
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Abstract
Crude mixtures of aspartic proteases from flowers of the plant Cynara cardunculus have been studied frequently, as have activities of such enzymes (in pure form) on caseins from bovine, ovine, and caprine sources. This research study addressed pure bovine whey protein as substrates; that is, alpha-lactalbumin (alphaLA) and beta-lactoglobulin (alpha-LG), submitted to hydrolysis by 1 of 2 aspartic proteases (cardosins A and B), previously extracted and purified from C. cardunculus. Samples collected, following incubation at 55 degrees C and pH 5.2, were assayed by fast protein liquid chromatography, reversed phase-high performance liquid chromatography, and tricine-sodium dodecyl sulfate polyacrylamide gel electrophoresis; the major peptides released were then collected and sequenced by Edman degradation. Cardosin B and, to a lesser degree, cardosin A showed proteolytic activity toward alpha-LA, but the hydrolyzates produced were characterized by distinct peptide profiles. Cardosin B possesses a broad specificity, and produces several hydrophobic peptides (at least 5, with molecular mass in the range 2 to 8 kDa) in the early stages, which eventually become more hydrophilic (with molecular mass below 2 kDa) at later stages of hydrolysis. Cardosin A was found to cleave alpha-LA at the peptide bonds Phe28-Arg29, Gly54-Tyr55, Ala59-Ile60, Leu71-Phe72, and Leu105-Thr106, whereas cardosin B cleaved Ala19-Glu20, Phe28-Arg29, Glu30-Leu31, Tyr37-Gly38, Trp45-Val46, Phe50-His51, Ala59-Ile60, Ser66-Thr67, Leu71-Phe72, Phe72-Gln73, Gln73-Ile74, Ile78-Trp79, Leu115-Asp116, and Leu124-Ala125. Conversely, cardosins A and B are apparently not active on beta-LG.
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Affiliation(s)
- R M Barros
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, P-4200-072 Porto, Portugal
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Silva SV, Malcata FX. Partial Identification of Water-Soluble Peptides Released at Early Stages of Proteolysis in Sterilized Ovine Cheese-Like Systems: Influence of Type of Coagulant and Starter. J Dairy Sci 2005; 88:1947-54. [PMID: 15905424 DOI: 10.3168/jds.s0022-0302(05)72870-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cheese-like systems were manufactured from sterilized ovine milk, using crude aqueous extracts of Cynara cardunculus or cardosin A isolated therefrom as clotting agent. The effect of adding a commercial starter culture was also assessed. The impact of the type of coagulant used during the initial 24 h of proteolysis was evaluated via separation of peptides in the water-soluble extracts by reverse-phase HPLC, followed by partial sequencing via Edman degradation. Cardosin A accounted for most events of primary proteolysis. The major cleavage sites were Phe105-Met106 in kappa-casein, and Leu127-Thr128, Ser142-Trp143, Leu165-Ser166, and Leu190-Tyr191 in beta-casein. The starter culture did not play an active role during the initial stages of ripening.
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Affiliation(s)
- S V Silva
- Escola Superior de Biotecnologia, P-4200-072 Porto, Portugal
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Carvalho AS, Silva J, Ho P, Teixeira P, Malcata FX, Gibbs P. Effect of various growth media upon survival during storage of freeze-dried Enterococcus faecalis and Enterococcus durans. J Appl Microbiol 2003; 94:947-52. [PMID: 12752801 DOI: 10.1046/j.1365-2672.2003.01853.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS The effects of three different growth media (MRS, M17 and Lee's) on survival during freeze-drying and subsequent storage of six strains of Enterococcus faecalis and two strains of E. durans were investigated. METHODS AND RESULTS Distinct Enterococcus spp. strains were grown on M17, MRS and Lee's broth, freeze-dried and stored at 20 degrees C in air under darkness. At regular intervals throughout storage, freeze-dried samples were rehydrated and then plated on M17 agar. CONCLUSIONS A higher survival rate during storage of dried E. durans was obtained when growth occurred in MRS. The same effect was not observed, however, for the majority of E. faecalis strains, which clearly survived better in the dried state when this organism had been grown in M17 or Lee's medium. SIGNIFICANCE AND IMPACT OF STUDY The survival of the dried Enterococcus spp. tested during storage was shown to be strain-specific and dependent on the growth medium.
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Affiliation(s)
- A S Carvalho
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto, Portugal
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17
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Abstract
Twelve isolates of lactic acid bacteria, belonging to the Lactobacillus, Lactococcus, Leuconostoc, and Enterococcus genera, were previously isolated from 180-d-old Serra da Estrela cheese, a traditional Portuguese cheese manufactured from raw milk and coagulated with a plant rennet. These isolates were subsequently tested for their ability to catabolize free amino acids, when incubated independently with each amino acid in free form or with a mixture thereof. Attempts were made in both situations to correlate the rates of free amino acid uptake with the numbers of viable cells. When incubated individually, leucine, valine, glycine, aspartic acid, serine, threonine, lysine, glutamic acid, and alanine were degraded by all strains considered; arginine tended to build up, probably because of transamination of other amino acids. When incubated together, the degradation of free amino acids by each strain was dependent on pH (with an optimum pH around 6.0). The volatiles detected in ripened Serra da Estrela cheese originated mainly from leucine, phenylalanine, alanine, and valine, whereas in vitro they originated mainly from valine, phenylalanine, serine, leucine, alanine, and threonine. The wild strains tested offer a great potential for flavor generation, which might justify their inclusion in a tentative starter/nonstarter culture for that and similar cheeses.
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Affiliation(s)
- F K Tavaria
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto
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18
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Moreira PR, Almeida-Vara E, Sena-Martins G, Polónia I, Malcata FX, Cardoso Duarte J. Decolourisation of Remazol Brilliant Blue R via a novel Bjerkandera sp. strain. J Biotechnol 2001; 89:107-11. [PMID: 11500203 DOI: 10.1016/s0168-1656(01)00320-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A novel strain of Bjerkandera sp. (B33/3), with particularly high decolourisation activities upon Poly R-478 and Remazol Brilliant Blue R (RBBR) dyes, was isolated. The role of the ligninolytic extracellular enzymes produced by this strain on decolourisation of RBBR was studied in some depth. The basis of decolourisation is an enzyme-mediated process, in which the main enzyme responsible is a recently described peroxidase with capacity for oxidation of manganese, as well as veratryl alcohol and 2,6-dimethoxyphenol in a manganese-independent reaction.
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Affiliation(s)
- P R Moreira
- Unidade de Bioengenharia e Bioprocessos, Instituto Nacional de Engenharia e Tecnologia Industrial, Estrada do Paço do Lumiar, 22, P-1649-038, Lisboa, Portugal
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19
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Pintado AI, Macedo AC, Teixeira G, Pais MS, Clemente A, Malcata FX. Caseinolytic activity of fruit extract from Opuntia ficus-indica on bovine, caprine, and ovine sodium caseinates. Biotechnol Prog 2001; 17:643-6. [PMID: 11485424 DOI: 10.1021/bp0100474] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The rates and extents of hydrolysis of alpha(S)- and beta-caseins from bovine, caprine, and ovine sodium caseinates produced by an enzymatic extract of the fruit of Opuntia ficus-indica, (L.) Miller were evaluated and compared with those produced by a commercial animal rennet. A mechanistic model based on a pseudo-first-order enzymatic reaction, in the presence of first-order deactivation of the enzyme, was postulated and successfully fitted to the experimental data. The animal rennet exhibited higher enzymatic efficiency than the fruit extract, irrespective of the source (i.e., bovine, caprine, or ovine) and the type (i.e., alpha(S)- or beta-casein) of substrate. The enzymatic efficiency (k(cat)/K(m)) for alpha(S)-casein ranged from 72 to 220 and from 43 to 65 L g(-1) h(-1), and for beta-casein from 242 to 742 and from 55 to 164 L g(-1) h(-1), for the animal rennet and the enzymatic extract of O. ficus-indica, respectively. Finally, it was observed that beta-casein from caprine and ovine caseinates was degraded by O. ficus-indica faster than its alpha(S) counterpart, but the reverse was observed for bovine caseinate.
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Affiliation(s)
- A I Pintado
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, P-4200-072 Porto, Portugal
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20
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Balcão VM, Mateo C, Fernández-Lafuente R, Malcata FX, Guisán JM. Structural and functional stabilization of L-asparaginase via multisubunit immobilization onto highly activated supports. Biotechnol Prog 2001; 17:537-42. [PMID: 11386876 DOI: 10.1021/bp000163r] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new protocol for the stabilization of the quaternary structure of multimeric enzymes has been attempted using as model enzyme (tetrameric) L-asparaginase from Escherichia coli. Such strategy is based upon multisubunit covalent immobilization of the enzyme onto activated supports (agarose-glutaraldehyde). Supports activated with different densities of reactive groups were used; the higher the density of groups, the higher the stabilization attained. However, because of the complexity of that enzyme, even the use of the highest densities of reactive groups was not enough to encompass all four subunits in the immobilization process. Therefore, a further chemical intersubunit cross-linking with aldehyde-dextran was pursued; these derivatives displayed a fully stabilized multimeric structure. In fact, boiling the modified enzyme derivative in the presence of sodium dodecyl sulfate and beta-mercaptoethanol did not lead to release of any enzyme subunit into the medium. Such a derivative, prepared under optimal conditions, retained ca. 40% of the intrinsic activity of the free enzyme and was also functionally stabilized, with thermostabilization enhancements of ca. 3 orders of magnitude when compared with its soluble counterpart. This type of derivative may be appropriate for extracorporeal devices in the clinical treatment of acute leukemia and might thus bring about inherent advantages in that all subunits are covalently bound to the support, with a longer half-life and a virtually nil risk of subunit release into the circulating blood stream.
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Affiliation(s)
- V M Balcão
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, P-4200-072 Porto, Portugal
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21
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Abstract
In attempts to improve the metabolic efficiency in closed photosynthetic reactors, availability of light and CO(2) are often considered as limiting factors, as they are difficult to control in a culture. The carbon source is usually provided via bubbling of CO(2)-enriched air into the culture medium; however, this procedure is not particularly effective in terms of mass transfer. Besides, it leads to considerable waste of that gas to the open atmosphere, which adds to operation costs. Increase in the interfacial area of contact available for gas exchange via use of membranes might be a useful alternative; microporous membranes, in hollow-fiber form, were tested accordingly. Two hollow-fiber modules, different in both hydrophilicity and outer surface area, were tested and duly compared, in terms of mass transfer, versus traditional plain bubbling. Overall volumetric coefficients (K(L)a) for CO(2) transfer were 1.48 x 10(-2) min(-1) for the hydrophobic membrane, 1.33 x 10(-2) min(-1) for the hydrophilic membrane, and 7.0 x 10(-3) min(-1) for plain bubbling. A model microalga, viz. Nannochloropsis sp., was cultivated using the two aforementioned membrane systems and plain bubbling. The produced data showed slight (but hardly significant) increases in biomass productivity when the hollow-fiber devices were used. However, hollow-fiber modules allow recirculation of unused CO(2), thus reducing feedstock costs. Furthermore, such indirect way of supplying CO(2) offers the additional possibility for use of lower gas pressures, as no need to counterbalance hydrostatic heads exists.
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Affiliation(s)
- A P Carvalho
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, P-4200-072 Porto, Portugal
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22
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Pintado ME, Santos CC, Malcata FX. Activity of adventitious Enterococcus strains on model curdled caprine milk: microbial growth and evolution of concentration of organic acids and lactose throughout time. Meded Rijksuniv Gent Fak Landbouwkd Toegep Biol Wet 2001; 66:613-6. [PMID: 15954666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Enterococci offer a few unique advantages when compared with other lactic acid bacteria in that they are resistant to phages, stable lactose fermenters, tolerant to relatively high concentrations of sodium chloride and optimal growers at relatively high temperatures (Franz et al., 1999). Such genus occurs and grows in a variety of cheeses, especially artisanal cheeses produced in Southern Europe usually from raw milk; they are claimed to play a major role in ripening and aroma development in such cheeses (Freitas et al., 1995; Macedo et al., 1995). Enterococci can produce lactic, acetic, propionic and succinic acids (Ocando et al., 1994), compounds that have been correlated with flavor characteristics of cheese; hence strains of Enterococcus have been successfully used as starters for different cheese (Franz et al., 1999).
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Affiliation(s)
- M E Pintado
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, P-4200-072 Porto, Portugal
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23
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Barros RM, Malcata FX. On the enzymatic hydrolysis of whey proteins brought about by cardosin a from Cynara carduncunlus. Meded Rijksuniv Gent Fak Landbouwkd Toegep Biol Wet 2001; 66:565-8. [PMID: 15954654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- R M Barros
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal
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24
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Abstract
This review focuses on the kinetics of several modes of immobilization of lipases, on the mechanisms of reactions of activation of immobilized lipases, and on the kinetics and mechanisms of reactions catalyzed by immobilized lipases. A comprehensive overview of the state of the art pertaining to structural features of lipases is provided as an aid to understand immobilization, interfacial activation, and catalytic performance. General rate expressions are duly derived; more frequent simplifying assumptions are stated and the results thereof listed. Physicochemical and statistical significance of parameters in rate expressions fitted to experimental data are also discussed whenever possible.
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Affiliation(s)
- AL Paiva
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. Antonio Bernardino de Almeida, 4200-072, Porto, Portugal
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25
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Abstract
In the Iberian Peninsula, the proteinases present in the flowers of members of the
Cynara genus, C. cardunculus, C. humilis and C. scolymus, have for many years been
successfully used in the manufacture of traditional cheeses from ovine and/or caprine
milk on individual farms (Vieira de Sá & Barbosa, 1972; Trujillo et al. 1994). In
Portugal, C. cardunculus is the species most frequently employed. Although
commercial thistle was tentatively assumed to be pure in taxonomic terms, accurate
analyses have shown that the flowers of C. cardunculus are often mixed with flowers
of C. humilis (Pires et al. 1994). The clotting activity of C. humilis is due to an
aspartic proteinase, currently designated cardosin A and similar to another enzyme
obtained from C. cardunculus. This enzyme is similar in specificity and activity to
chymosin (Pires et al. 1994).The action of cardosin A from C. cardunculus upon ovine and caprine caseins has
been reported recently (Ramalho-Santos et al. 1996; Simo4es, 1998; Sousa & Malcata,
1998), but as yet there is no information on the proteolytic activity of the proteinase
from C. humilis upon caseins from milks other than bovine. Caseins from small
ruminants' milks are the usual substrates of cardosin during milk coagulation and
cheese ripening, and sodium caseinate represents an intermediate system between
isolated caseins and the cheese matrix that is free from interference by fat. Thus
ovine and caprine caseinates may be useful substrates for investigating the
proteolytic activity of cardosin.The aim of the present study was to compare the action of pure cardosin A,
obtained from C. humilis, on caprine and ovine caseinates, and to assess the in vitro
contribution of this enzyme to the overall proteolytic action of thistle rennet.
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Affiliation(s)
- S V Silva
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto, Portugal
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26
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Freitas C, Malcata FX. Microbiology and biochemistry of cheeses with Appélation d'Origine Protegée and manufactured in the Iberian Peninsula from ovine and caprine milks. J Dairy Sci 2000; 83:584-602. [PMID: 10750117 DOI: 10.3168/jds.s0022-0302(00)74918-6] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To support legal protection with objective technical data and to promote enforcement of high quality standards a few European countries have created Appélation d'Origine Protegées. This paper reviews and updates fundamental and applied aspects encompassing microbiological and biochemical characteristics of traditional cheeses with Appélation d'Origine Protegée manufactured in the Iberian Peninsula from ovine, caprine, or both milks. Ovine and caprine cheeses with Appélation d'Origine Protegée from Portugal and Spain can be divided into four distinct groups based on milk source and rennet type: 1) Azeitão, Castelo Branco, Evora, Nisa, Serpa, Serra da Estrela, and La Serena cheeses are manufactured with raw ovine milk and coagulated via plant rennet; 2) Terrincho, Idiazábal, Manchego, Roncal, and Zamorano cheeses are manufactured with raw ovine milk and coagulated via animal rennet; 3) Cabra Transmontano and Majorero are manufactured with raw caprine milk and coagulated via animal rennet; and 4) Amarelo da Beira Baixa, Picante da Beira Baixa, and Rabaçal are manufactured with mixtures of raw ovine and caprine milks and coagulated via animal rennet.
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27
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Abstract
Vacuum packaging was assayed at 4 degrees C and was tested in comparison to unpackaged counterparts, in both microbiological and physicochemical terms, in studies pertaining to the preservation of Requeijão, a traditional Portuguese whey cheese. Bacteria were absent (i.e., <10 CFU/g) in whey cheeses on the day of manufacture as a result of thermal processing. After storage, both unpackaged and packaged cheeses exhibited high viable counts of Bacillus, Pseudomonas, Enterobacteriaceae, and lactic acid bacteria (especially lactococci). Yeasts, staphylococci, enterococci, and spore-forming clostridia were severely inhibited by the package vacuum combined with the increasing acidification developed therein. Whey cheeses packaged under vacuum underwent substantial acidification, slight depletion of lactose, and no significant variation in moisture content or texture; conversely, unpackaged whey cheeses exhibited substantial loss of water and a concomitant increase in rigidity. Vacuum packaging strongly inhibited lipolysis (even if viable counts of some microbial groups were high); saturated fatty acids (mainly C16:0 and C14:0) accounted for ca. 73% of the total free-fatty acid content, whereas the most concentrated unsaturated fatty acids were C18:1 and C18:2 (ca. 14% each). The conclusions generated in our study are, in general, useful for a wide range of whey cheeses worldwide: i.e., Requéson (Spain), Ricotta (Italy), Broccio (France), and Anthotyro (Greece). In addition, our conclusions are particularly helpful in terms of improving the safety of Requeijão, a widely acclaimed dairy specialty.
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Affiliation(s)
- M E Pintado
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto, Portugal
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28
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Abstract
Traditional manufacture of bread from maize has been noted to play important roles from both economic and social standpoints; however, enforcement of increasingly strict hygiene standards requires thorough knowledge of the adventitious microbiota of the departing dough. To this goal, sourdough as well as maize and rye flours from several geographic locations and in two different periods within the agricultural year were assayed for their microbiota in sequential steps of quantification and identification. More than 400 strains were isolated and taxonomic differentiation between them was via Biomerieux API galleries (375 of which were successfully identified) following preliminary biochemical and morphological screening. The dominant groups were yeasts and lactic acid bacteria (LAB). The most frequently isolated yeasts were Saccharomyces cerevisiae and Candida pelliculosa. The most frequently isolated LAB were (heterofermentative) Leuconostoc spp. and (homofermentative) Lactobacillus spp.; L. brevis, L. curvatus, and L. lactis ssp. lactis were the dominant species for the Lactobacillus genera; Lactococcus lactis ssp. lactis for lactococci; Enterococcus casseliflavus, E. durans, and E. faecium for enterococci; and Streptococcus constellantus and S. equinus for streptococci.
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Affiliation(s)
- J M Rocha
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto
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29
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Freitas AC, Pintado AE, Pintado ME, Malcata FX. Organic acids produced by lactobacilli, enterococci and yeasts isolated from Picante cheese. Eur Food Res Technol 1999. [DOI: 10.1007/s002170050522] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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30
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Malcata FX. ADSA Foundation Scholar Award. Critical issues affecting the future of dairy industry: individual contributions in the scope of a global approach. J Dairy Sci 1999; 82:1595-611. [PMID: 10480086 DOI: 10.3168/jds.s0022-0302(99)75388-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Several constraints that have been affecting the dairy industry are identified in a critical fashion, and directions are given with an emphasis on food processing implemented at the postproduction level. The rationale for modifications aimed at enhancing the appeal of condensed dairy products should be consubstantiated in strengthening of organoleptic characteristics, improvement of nutraceutical impact, and reduction of polluting power. This enumeration follows an order of increasing time scale required for consumer perception and increasing size scale associated with expected impact. Pursuance of such streamlines should lead to manufacture of dairy products that resemble nature more closely in terms of milk coagulation, milk fat modification, milk fermentation, whey fermentation, and starter culture addition. Directions for research and development anticipated as useful and effective in this endeavor, and which have been previously and consistently adopted in the development of an individual research program, are characterization and development of alternative rennets from plant sources, development of starter and nonstarter cultures from adventitious microflora, utilization of probiotic strains as starter cultures, upgrading of whey via physical or fermentation routes, and modification of milk fat via lipase-mediated interesterification reactions.
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Affiliation(s)
- F X Malcata
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto, Portugal
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32
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Silva ML, Malcata FX. Effects of time of grape pomace fermentation and distillation cuts on the chemical composition of grape marcs. ACTA ACUST UNITED AC 1999. [DOI: 10.1007/s002170050390] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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33
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Carvalho AP, Meireles LA, Malcata FX. Rapid spectrophotometric determination of nitrates and nitrites in marine aqueous culture media. ACTA ACUST UNITED AC 1998. [DOI: 10.1051/analusis:1998183] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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34
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Abstract
The determination of the best conditions of preparation of a (tentatively) probiotic starter culture that might be suitable for cheese making composed solely of Bifidobacterium lactis Bo and Lactobacillus acidophilus Ki is critical if a consistently reliable acid production is to be achieved, especially because bifidobacteria have stringent requirements for growth. Therefore, we determined whether B. lactis Bo and L. acidophilus Ki required or benefitted from the addition of milk hydrolyzates (brought about by proteinase or neutrase as the nitrogen source). The growth and acid production of B. lactis in milk were affected by the addition of proteinase-mediated hydrolyzate and, to a lesser extent, by neutrase-mediated hydrolyzate; a higher degree of hydrolysis of either hydrolyzate resulted in greater biomass increase and greater acid production. This result suggests that the poor growth of bifidobacteria in milk is due partially to the lack of small peptides and free amino acids. The rates of growth and acidification by B. lactis were enhanced when cocultured with L. acidophilus (1:1 inoculum ratio). Conversely, the growth rates and acid production of L. acidophilus were not positively affected by the addition of either milk hydrolyzate. Although L. acidophilus grew slowly, its proteolytic system was apparently able to generate its own nitrogen source. Nevertheless, coculture with B. lactis (1:1 inoculum ratio) led to enhanced rates of growth and acidification when compared with that of the single strain, suggesting some degree of symbiosis between the strains.
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Affiliation(s)
- A M Gomes
- Escola Superior de Biotecnolgia, Universidade Católica Portuguesa, Portugal
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35
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Gomes AM, Malcata FX. Use of small ruminants' milk supplemented with available nitrogen as growth media for Bifidobacterium lactis and Lactobacillus acidophilus. J Appl Microbiol 1998; 85:839-48. [PMID: 9830119 DOI: 10.1046/j.1365-2672.1998.00594.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Growth of, and acid production by Bifidobacterium lactis and Lactobacillus acidophilus using ovine and caprine milk as media were evaluated for their potential use in cheese-making. A protein hydrolysate (MHP, obtained from incubation of bovine milk with protease) or a mixture of free amino acids (FAA, similar to the amino acid fraction of MHP) was added as a nitrogen enrichment source. Bifidobacterium lactis and Lact. acidophilus were inoculated at 50 ml l-1 and incubated at 37 degrees C with growth supplements added at ratios in the range 25-50 ml l-1. The maximum viable counts of Bif. lactis were lower in plain ovine and caprine milk than in nitrogen-enriched milk, and MHP was a better growth promoter than FAA. A similar trend was observed with the acidity values developed, and attempts to correlate growth with acidity were successfully performed. The highest uptake rates of amino acids in ovine milk were observed for lysine, isoleucine, leucine and proline, but only isoleucine was taken up at a similar rate in caprine milk. Final bacterial viable counts of Lact. acidophilus in the plain and enriched forms of ovine milk did not differ greatly from each other, although FAA was statistically a better growth promoter than MHP. Unlike results in ovine milk, cultures of Lact. acidophilus in caprine milk exhibited drops of 1-1.5 log cycles in viable cell counts by 24 h of fermentation, irrespective of the nature of the nitrogen source. Parallel studies indicated that the excess of fatty acid residues in caprine milk could be responsible for the poor growth of Lact. acidophilus.
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Affiliation(s)
- A M Gomes
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto, Portugal
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36
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Abstract
The present communication describes the chemical modification of anhydrous butterfat by interesterification with oleic acid catalyzed by a lipase of Mucor javanicus. Two reactor configurations were tested, a batch-stirred tank reactor containing suspended lipase and a batch-stirred tank reactor in combination with a hollow-fiber membrane module containing adsorbed lipase. The goal of this research was to assess the advantage of using a (hydrophobic) porous support to immobilize the lipase in attempts to engineer butterfat with increased levels of unsaturated fatty acid residues (oleic acid) at the expense of medium-to-long chain saturated fatty acids (myristic and palmitic acids). Reactions were carried out at 40 degrees C in the absence of solvent under controlled water activity, and were monitored by chromatographic assays for free fatty acids. The results obtained indicate that the rate of interesterification using the proposed reactor configuration is enhanced by a factor above 100 relative to that using suspended lipase, for the same protein mass basis. Although hydrolysis of butterfat occurred to some degree, the enzymatic process that uses the hollow-fiber reactor was technically superior to the stirred tank system. Copyright 1998 John Wiley & Sons, Inc.
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Affiliation(s)
- VM Balcao
- Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, Rua Dr. Antonio Bernardino de Almeida, P-4200 Porto, Portugal
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37
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38
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Abstract
Production of caprine milk has been rising steadily, partially because of its good nutritional value; the possibility of improving nutritional benefits by adding probiotic species such as Bifidobacterium lactis and Lactobacillus acidophilus was assessed. The manufacturing process of a traditional semi-hard goat cheese was technologically modified to optimize the process. The amount of starter inoculum, the concentration of salt, the addition of a protein hydrolysate, and the ripening time were varied to improve the microbiological, biochemical, and sensory properties of the cheese. Bifidobacterium lactis was able to grow slightly (up to 3 x 10(8) cfu/g), but growth was dependent on the physicochemical characteristics of the cheese. Lactobacillus acidophilus did not grow substantially in any of the experimental cheeses, and maximum numbers did not exceed 6 x 10(7) cfu/g. Concentrations of lactic acid and acetic acid increased throughout cheese manufacture, indicating that production of these acids was uncoupled from growth. Viability of the probiotic strains during ripening was sufficient to yield numbers that were above the accepted threshold (10(6) cfu/g) for a probiotic effect. Both strains contributed significantly to ripening, especially in the formation of low molecular mass peptides and amino acids, but lipolysis was not greatly affected. Statistical analyses using response surface methodology indicated that the manufacture of goat cheese could be optimized by the addition of 0.30% (vol/wt) milk hydrolysate, 3 x 10(7) of viable B. lactis and 7 x 10(6) of viable L. acidophilus cells/ml of milk, respectively, 3.50% (wt/wt) salt, and ripening for 70 d.
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Affiliation(s)
- A M Gomes
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto, Portugal
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39
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Abstract
The purpose of this study was to assess the typical microbiological quality of the most famous Portuguese traditional cheese, Serra da Estrela, and to assess its ripening time and geographical dependence. Ninety-six experimental cheeses manufactured from sixteen batches of milk on eight dairy farms scattered over the Appellation d' Origine Protégée (AOP) region were qualitatively and quantitatively evaluated microbiologically at various ripening times. Viable counts were performed after inoculation on appropriate selective media for aerobic mesophiles and proteolytic and lipolytic microflora, as well as lactococci, lactobacilli, species of Enterobacteriaceae, lactic streptococci, staphylococci, and yeasts. Members of the Enterobacteriaceae and lactic acid bacteria were the predominant microbial groups on all dairy farms throughout maturation; the latter are probably the microbial group responsible for most proteolytic and lipolytic breakdown in Serra da Estrela cheese. The microbial groups whose numbers were most affected by dairy-to-dairy variation were species of Enterobacteriaceae staphylococci, and enterococci, which are the most critical groups in terms of health hazards. It is therefore suggested that tighter control should be implemented at the level of choice of raw materials, in milk-handling practices, and in general throughout the manufacturing process in attempts to standardize production and consistently reduce microbiological risks (even though the distinctiveness of a few final organoleptic characteristics may somehow be reduced.
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Affiliation(s)
- F K Tavaria
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto, Portugal
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40
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Abstract
The distribution of micro-organisms in mature Serra, a traditional Portuguese cheese made from unpasteurised ewes' milk without added starter culture, was examined by light microscopy and electron microscopy. Four populations of micro-organisms were recognized according to their position within the cheese: (i) those present as apparently axenic colonies within the curd matrix; (ii) bacteria growing along curd junctions; (iii) yeasts and bacteria present in the smear on the surface of the cheese and (iv) bacteria found in cracks which penetrated the outer part of the cheese from the rind. Two types of crystals were observed, together with contaminants of vegetable origin and somatic cells originating from the milk.
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Affiliation(s)
- M L Parker
- Institute of Food Research, Colney, Norwich, UK
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41
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Abstract
Decreasing consumption of high fat milk and dairy products is driving the dairy industry to seek other uses for increasing surplus of milkfat. Enzyme catalyzed modification of milkfat using lipases is receiving particular attention. This review examines lipase-mediated modification of milkfat. Especial attention is given to industrial applications of lipases for producing structured and modified milkfat for improved physical properties and digestibility, reduced caloric value, and flavor enhancement. Features associated with reactions such as hydrolysis, transesterification, alcoholysis and acidolysis are presented with emphasis on industrial feasibility, marketability and environmental concerns. Future prospects for enzyme catalyzed modification of milk fat are discussed.
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Affiliation(s)
- V M Balcão
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, P-4200 Porto, Portugal
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42
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Sousa MJ, Malcata FX. Comparative biochemical evolution during ripening of bovine, ovine and caprine cheeses manufactured with extracts of flowers of Cynara cardunculus. ACTA ACUST UNITED AC 1997. [DOI: 10.1007/s002170050132] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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43
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44
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Moreira NE, Malcata FX. On the optimum distribution of enzyme feed in a cascade of CSTR's performing an enzyme-catalyzed reaction with deactivation. Bioprocess Biosyst Eng 1996. [DOI: 10.1007/bf02426438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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45
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Abstract
This review attempts to provide an updated compilation of studies reported in the literature pertaining to reactors containing lipases in immobilized forms, in a way that helps the reader direct a bibliographic search and develop an integrated perspective of the subject. Highlights are given to industrial applications of lipases (including control and economic considerations), as well as to methods of immobilization and configurations of reactors in which lipases are used. Features associated with immobilized lipase kinetics such as enzyme activities, adsorption properties, optimum operating conditions, and estimates of the lumped parameters in classical kinetic formulations (Michaelis-Menten model for enzyme action and first-order model for enzyme decay) are presented in the text in a systematic tabular form.
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Affiliation(s)
- V M Balcão
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto
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46
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Abstract
Ten commercially available crude preparations of lipase from various microbial sources were adsorbed from aqueous buffers at several initial concentrations onto a bundle of hydrophobic hollow fibers made of poly(propylene) at pH 7.0 and 40 degrees C. The kinetics of adsorption were evaluated from measurements at various times of the protein content of the supernatant solution (using BSA as equivalent) in a well-mixed reservoir placed in series with the hollow fiber module. Preliminary tracer experiments have indicated that the module and the tank can be simulated as a system consisting of a plug flow reactor in series with a continuous stirred tank reactor. A mechanistic model based on the hydrodynamic assumptions associated with this system coupled with the postulation of two reversible first-order steps for the adsorption of protein was successfully fitted to the experimental data via nonlinear regression analysis. The statistical significance of the model was checked using tests for lack of fit. This work is useful in predicting the time period required to immobilize a (crude) lipase by adsorption onto a hydrophobic hollow fiber module, a configuration which has proved successful in the recent past for the performance of lipase-catalyzed reactions.
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Affiliation(s)
- V M Balcao
- Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, Porto, Portugal
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47
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Macedo AC, Costa ML, Malcata FX. Assessment of proteolysis and lipolysis in Serra cheese: effects of axial cheese location, ripening time and lactation season. ACTA ACUST UNITED AC 1996. [DOI: 10.1051/lait:1996427] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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48
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Affiliation(s)
- F X Malcata
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto
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49
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Malcata FX. Strategy for the simulation of batch reactors when the enzyme-catalyzed reaction is accompanied by enzyme deactivation. Bioprocess Biosyst Eng 1994. [DOI: 10.1007/bf00369611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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50
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Silva TR, Malcata FX. On the appropriateness of use of a continuous formulation for the modelling of discrete multireactant systems following Micha�lis-Menten kinetics. Bioprocess Biosyst Eng 1994. [DOI: 10.1007/bf00369535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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