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Brandsma JB, Rustandi N, Brinkman J, Wolkers‐Rooijackers JCM, Zwietering MH, Smid EJ. Pivotal role of cheese salting method for the production of 3‐methylbutanal by
Lactococcus lactis. INT J DAIRY TECHNOL 2021. [DOI: 10.1111/1471-0307.12839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | - Marcel H Zwietering
- Wageningen University & Research Food Microbiology P.O. Box 17 6700 AA Wageningen The Netherlands
| | - Eddy J Smid
- Wageningen University & Research Food Microbiology P.O. Box 17 6700 AA Wageningen The Netherlands
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Khattab AR, Guirguis HA, Tawfik SM, Farag MA. Cheese ripening: A review on modern technologies towards flavor enhancement, process acceleration and improved quality assessment. Trends Food Sci Technol 2019. [DOI: 10.1016/j.tifs.2019.03.009] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Stefanovic E, Kilcawley KN, Rea MC, Fitzgerald GF, McAuliffe O. Genetic, enzymatic and metabolite profiling of the Lactobacillus casei group reveals strain biodiversity and potential applications for flavour diversification. J Appl Microbiol 2017; 122:1245-1261. [PMID: 28199757 DOI: 10.1111/jam.13420] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/06/2017] [Accepted: 02/08/2017] [Indexed: 01/22/2023]
Abstract
AIMS The Lactobacillus casei group represents a widely explored group of lactic acid bacteria, characterized by a high level of biodiversity. In this study, the genetic and phenotypic diversity of a collection of more than 300 isolates of the Lact. casei group and their potential to produce volatile metabolites important for flavour development in dairy products, was examined. METHODS AND RESULTS Following confirmation of species by 16S rRNA PCR, the diversity of the isolates was determined by pulsed-field gel electrophoresis. The activities of enzymes involved in the proteolytic cascade were assessed and significant differences among the strains were observed. Ten strains were chosen based on the results of their enzymes activities and they were analysed for their ability to produce volatiles in media with increased concentrations of a representative aromatic, branched chain and sulphur amino acid. Volatiles were assessed using gas chromatography coupled with mass spectrometry. Strain-dependent differences in the range and type of volatiles produced were evident. CONCLUSIONS Strains of the Lact. casei group are characterized by genetic and metabolic diversity which supports variability in volatile production. SIGNIFICANCE AND IMPACT OF THE STUDY This study provides a screening approach for the knowledge-based selection of strains potentially enabling flavour diversification in fermented dairy products.
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Affiliation(s)
- E Stefanovic
- Department of Food Bioscience, Teagasc Food Research Centre, Moorepark, Fermoy, Ireland.,School of Microbiology, University College Cork, Cork, Ireland
| | - K N Kilcawley
- Department of Food Bioscience, Teagasc Food Research Centre, Moorepark, Fermoy, Ireland
| | - M C Rea
- Department of Food Bioscience, Teagasc Food Research Centre, Moorepark, Fermoy, Ireland
| | - G F Fitzgerald
- School of Microbiology, University College Cork, Cork, Ireland
| | - O McAuliffe
- Department of Food Bioscience, Teagasc Food Research Centre, Moorepark, Fermoy, Ireland
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Bonomo MG, Cafaro C, Salzano G. Genotypic and technological diversity of Brevibacterium linens strains for use as adjunct starter cultures in 'Pecorino di Filiano' cheese ripened in two different environments. Folia Microbiol (Praha) 2015; 60:61-7. [PMID: 25147054 DOI: 10.1007/s12223-014-0341-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 08/06/2014] [Indexed: 10/24/2022]
Abstract
Twenty-two Brevibacterium linens strains isolated from 'Pecorino di Filiano' cheese ripened in two different environments (natural cave and storeroom) were characterized and differentiated for features of technological interest and by genotypic methods, in order to select strains with specific features to be used as surface starter cultures. Results showed significant differences among strains on the basis of physiological and technological features, indicating heterogeneity within the species. A middle-low level of proteolytic activity was observed in 27.3 % of strains, while a small group (9.1 %) showed a high ability. Lipolytic activity was observed at three different temperatures and the highest value was detected at 20 °C with 13.6 % of strains, while an increase in temperature produced a slightly lower lipolysis in all strains. The evaluation of diacetyl production revealed that only 22.8 % of strains showed this ability, and most of them were isolated from product ripened in the natural cave. All strains exhibited only leu-aminopeptidase activity, with values more elevated in strains coming from the natural cave product. The combined analysis of genotypic results with the data obtained by the features of technological interest study established that the random amplified polymorphic DNA (RAPD) clusters obtained were composed not only of different genotypes but of different profiles based on technological properties too. This study demonstrated the importance of the ripening environment that affects the typical features of the artisanal product, leading to the selection of a specific surface microflora. Characterized strains could be associated within surface starters to standardize the production process of cheese, but preserving its typical organoleptic and sensory characteristics and improving the quality of the final product.
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Ganesan B, Brown K. Informatic prediction of Cheddar cheese flavor pathway changes due to sodium substitution. FEMS Microbiol Lett 2013; 350:231-8. [DOI: 10.1111/1574-6968.12328] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 10/20/2013] [Indexed: 11/30/2022] Open
Affiliation(s)
- Balasubramanian Ganesan
- Dairy Technology and Innovation Laboratory; Western Dairy Center; Department of Nutrition, Dietetics, and Food Sciences; Utah State University; Logan UT USA
| | - Kelly Brown
- Dairy Technology and Innovation Laboratory; Western Dairy Center; Department of Nutrition, Dietetics, and Food Sciences; Utah State University; Logan UT USA
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Broadbent J, Cai H, Larsen R, Hughes J, Welker D, De Carvalho V, Tompkins T, Ardö Y, Vogensen F, De Lorentiis A, Gatti M, Neviani E, Steele J. Genetic diversity in proteolytic enzymes and amino acid metabolism among Lactobacillus helveticus strains. J Dairy Sci 2011; 94:4313-28. [DOI: 10.3168/jds.2010-4068] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 04/23/2011] [Indexed: 01/17/2023]
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Ávila M, Calzada J, Garde S, Nuñez M. Effect of a bacteriocin-producing Lactococcus lactis strain and high-pressure treatment on the esterase activity and free fatty acids in Hispánico cheese. Int Dairy J 2007. [DOI: 10.1016/j.idairyj.2007.04.004] [Citation(s) in RCA: 19] [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: 11/17/2022]
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Kieronczyk A, Cachon R, Feron G, Yvon M. Addition of oxidizing or reducing agents to the reaction medium influences amino acid conversion to aroma compounds by Lactococcus lactis. J Appl Microbiol 2006; 101:1114-22. [PMID: 17040235 DOI: 10.1111/j.1365-2672.2006.02999.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [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 The aim of this research was to investigate the impact of extracellular redox potential (Eh) on amino acid conversion to aroma compounds by Lactococcus lactis that is commonly used as a starter in the cheese industry. METHODS AND RESULTS The study was realized in vitro by incubating resting cells of L. lactis in reaction media in which E(h) was modified by the addition of oxidizing or reducing agents. Oxidative condition (+300 mV) favoured the production of aldehydes and volatile sulfur compounds responsible for malty, floral, fruity, almond and cabbage aroma. This production was mainly the result of a chemical oxidation of the alpha-keto acids produced by amino acid transamination. In contrast, reducing condition (-200 mV) stimulated the production of carboxylic acids such as phenylacetic, methylthiopropionic and isovaleric acids, which contribute to the very-ripened-cheese aroma as well as the production of hydroxy acids. CONCLUSIONS Eh of the medium highly influences the nature of aroma compounds produced from amino acid catabolism by the resting cells of L. lactis. SIGNIFICANCE AND IMPACT OF THE STUDY E(h) is a parameter that is not controlled during cheese production. Its control throughout cheese making and ripening could permit control of aroma formation in cheese.
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Affiliation(s)
- A Kieronczyk
- Unité de Biochimie et Structure des Protéines, INRA, Jouy-en-Josas, France
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Abstract
Cheese is one of the dairy products that can result from the enzymatic coagulation of milk. The basic steps of the transformation of milk into cheese are coagulation, draining, and ripening. Ripening is the complex process required for the development of a cheese's flavor, texture and aroma. Proteolysis, lipolysis and glycolysis are the three main biochemical reactions that are responsible for the basic changes during the maturation period. As ripening is a relatively expensive process for the cheese industry, reducing maturation time without destroying the quality of the ripened cheese has economic and technological benefits. Elevated ripening temperatures, addition of enzymes, addition of cheese slurry, attenuated starters, adjunct cultures, genetically engineered starters and recombinant enzymes and microencapsulation of ripening enzymes are traditional and modern methods used to accelerate cheese ripening. In this context, an up to date review of Cheddar cheese ripening is presented.
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Affiliation(s)
- Sorayya Azarnia
- Department of Food Science and Agricultural Chemistry, McGill University, Ste-Anne-de-Bellevue, QC, Canada
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Arvanitoyannis IS, Tzouros NE. Implementation of Quality Control Methods in Conjunction with Chemometrics Toward Authentication of Dairy Products. Crit Rev Food Sci Nutr 2005; 45:231-49. [PMID: 16047492 DOI: 10.1080/10408690490478073] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [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: 10/25/2022]
Abstract
The implementation of novel and accurate quality and safety control methods in conjunction with chemometrics in various fields of science, particularly in food science, showed that this combination stands for a very powerful tool for detecting food authenticity. The latter reflects both geographic origin and variety. Dairy products, in particular, have repeatedly worried the public authorities in terms of authentication regarding origin and in view of the many illnesses occasionally due to products of specific origin. Therefore, the development of a robust and reliable system endowed with this discriminatory power (varietal and/or geographic) is of great importance, both in terms of public health and consumer protection.
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Affiliation(s)
- Ioannis S Arvanitoyannis
- University of Thessaly, School of Agricultural Sciences, Department of Animal Production & Aquatic Environment, Fytokou Street, Nea Ionia Magnesias, 98446 Volos, Greece.
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Abstract
Low concentrations of branched-chain fatty acids, such as isobutyric and isovaleric acids, develop during the ripening of hard cheeses and contribute to the beneficial flavor profile. Catabolism of amino acids, such as branched-chain amino acids, by bacteria via aminotransferase reactions and alpha-keto acids is one mechanism to generate these flavorful compounds; however, metabolism of alpha-keto acids to flavor-associated compounds is controversial. The objective of this study was to determine the ability of Brevibacterium linens BL2 to produce fatty acids from amino acids and alpha-keto acids and determine the occurrence of the likely genes in the draft genome sequence. BL2 catabolized amino acids to fatty acids only under carbohydrate starvation conditions. The primary fatty acid end products from leucine were isovaleric acid, acetic acid, and propionic acid. In contrast, logarithmic-phase cells of BL2 produced fatty acids from alpha-keto acids only. BL2 also converted alpha-keto acids to branched-chain fatty acids after carbohydrate starvation was achieved. At least 100 genes are potentially involved in five different metabolic pathways. The genome of B. linens ATCC 9174 contained these genes for production and degradation of fatty acids. These data indicate that brevibacteria have the ability to produce fatty acids from amino and alpha-keto acids and that carbon metabolism is important in regulating this event.
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Amarita F, Yvon M, Nardi M, Chambellon E, Delettre J, Bonnarme P. Identification and functional analysis of the gene encoding methionine-gamma-lyase in Brevibacterium linens. Appl Environ Microbiol 2005; 70:7348-54. [PMID: 15574935 PMCID: PMC535188 DOI: 10.1128/aem.70.12.7348-7354.2004] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [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] Open
Abstract
The enzymatic degradation of L-methionine and subsequent formation of volatile sulfur compounds (VSCs) is believed to be essential for flavor development in cheese. L-methionine-gamma-lyase (MGL) can convert L-methionine to methanethiol (MTL), alpha-ketobutyrate, and ammonia. The mgl gene encoding MGL was cloned from the type strain Brevibacterium linens ATCC 9175 known to produce copious amounts of MTL and related VSCs. The disruption of the mgl gene, achieved in strain ATCC 9175, resulted in a 62% decrease in thiol-producing activity and a 97% decrease in total VSC production in the knockout strain. Our work shows that L-methionine degradation via gamma-elimination is a key step in the formation of VSCs in B. linens.
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Affiliation(s)
- Felix Amarita
- Unité Mixte de Recherches Génie et Microbiologie des Procédés Alimentaires, Institut National de la Recherche Agronomique, Thiverval-Grignon, France
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Abstract
The effects of the adjunct cultures Lactococcus lactis ssp. diacetylactis, Brevibacterium linens BL2, Lactobacillus helveticus LH212, and Lactobacillus reuteri ATCC 23272 on volatile free fatty acid production in reduced-fat Edam cheese were studied. Lipase activity evaluation using p-nitrophenyl fatty acid ester substrates indicated that L. lactis ssp. diacetylactis showed the highest activity among the 4 adjunct cultures. Full-fat and 33% reduced-fat control cheeses (no adjunct) were made along with 5 treatments of reduced-fat cheeses, which included individual, and a mixture of the adjunct cultures. Volatile free fatty acids of cheeses were analyzed using static headspace analysis with 4-bromofluorobenzene as an internal standard. Changes in volatile free fatty acid concentrations were found in headspace gas of cheeses after 3-and 6-mo ripening. Acetic acid was the most abundant acid detected throughout ripening. Full-fat cheese had the highest relative amount of propionic acid among the cheeses. Certain adjunct cultures had a definite role in lipolysis at particular times. Reduced-fat cheese with L. lactis ssp. diacetylactis at 3-mo showed the highest levels of butyric, isovaleric, n-valeric, iso-caproic, and n-caproic acid. Reduced-fat cheese with Lactobacillus reuteri at 6 mo produced the highest relative concentration of isocaproic, n-caproic, and heptanoic, and the highest relative concentration of total acids.
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Affiliation(s)
- W Tungjaroenchai
- Department of Food Science and Technology, Mississippi State University, 39762, USA
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Liu SQ, Holland R, Crow VL. The potential of dairy lactic acid bacteria to metabolise amino acids via non-transaminating reactions and endogenous transamination. Int J Food Microbiol 2003; 86:257-69. [PMID: 12915037 DOI: 10.1016/s0168-1605(03)00040-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [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: 10/27/2022]
Abstract
The metabolism of amino acids by 22 starter and 49 non-starter lactic acid bacteria (LAB) was studied in a system consisting of amino acids and non-growing cells without added amino acceptors such as alpha-ketoglutarate. There were significant inter- and intra-species differences in the metabolism of amino acids. Some amino acids such as alanine, arginine, aspartate, serine and branched-chain amino acids (leucine, isoleucine and valine) were utilised, whereas other amino acids such as glycine, ornithine and citrulline were produced. Alanine and aspartate were utilised by some LAB and accumulated during the incubation of other LAB. Arginine was degraded not only by Lactococcus lactis subsp. lactis (the lactococcal subspecies known to catabolise arginine), but also by pediococci, heterofermentative lactobacilli (Lactobacillus brevis and Lb. fermentum) and some unidentified homofermentative lactobacilli. Serine was utilised predominantly by homofermentative Lb. paracasei subsp. paracasei, Lb. rhamnosus and Lb. plantarum. Of the LAB studied, Lb. brevis and Lb. fermentum were the most metabolically active, utilising alanine, arginine, aspartate, glutamate and branched-chain amino acids. Leuconostocs were the least metabolically active, showing little potential to metabolise amino acids. The formation of ammonia and acetate from amino acid metabolism varied both between species and between strains within species. These findings suggest that the potential of LAB for amino acid metabolism via non-transaminating reactions and endogenous transamination will impact both on the physiology of LAB and on cheese ripening, especially when transamination is rate-limiting in the absence of an exogenous amino acceptor such as alpha-ketoglutarate.
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Affiliation(s)
- S-Q Liu
- Fonterra Research Centre, Private Bag 11 029, Palmerston North, New Zealand.
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Abstract
This study investigated population dynamics of starter, adjunct, and nonstarter lactic acid bacteria (NSLAB) in reduced-fat Cheddar and Colby cheese made with or without a Lactobacillus casei adjunct. Duplicate vats of cheese were manufactured and ripened at 7 degrees C. Bacterial populations were monitored periodically by plate counts and by DNA fingerprinting of cheese isolates with the random amplified polymorphic DNA technique. Isolates that displayed a unique DNA fingerprint were identified to the species level by partial nucleotide sequence analysis of the 16S rRNA gene. Nonstarter biota in both cheese types changed over time, but populations in the Colby cheese showed a greater degree of species heterogeneity. The addition of the L. casei adjunct to cheese milk at 10(4) cfu/ml did not completely suppress "wild" NSLAB populations, but it did appear to reduce nonstarter species and strain diversity in Colby and young Cheddar cheese. Nonetheless, nonstarter populations in all 6-mo-old cheeses were dominated by wild L. casei. Interestingly, the dominant strains of L. casei in each 6-mo-old cheese appeared to be affected more by adjunct treatment and not cheese variety.
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Affiliation(s)
- J R Broadbent
- Western Dairy Center, Department of Nutrition and Food Sciences, Utah State University, Logan 84322-8700, USA.
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Kieronczyk A, Skeie S, Langsrud T, Yvon M. Cooperation between Lactococcus lactis and nonstarter lactobacilli in the formation of cheese aroma from amino acids. Appl Environ Microbiol 2003; 69:734-9. [PMID: 12570989 PMCID: PMC143583 DOI: 10.1128/aem.69.2.734-739.2003] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [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: 11/20/2022] Open
Abstract
In Gouda and Cheddar type cheeses the amino acid conversion to aroma compounds, which is a major process for aroma formation, is essentially due to lactic acid bacteria (LAB). In order to evaluate the respective role of starter and nonstarter LAB and their interactions in cheese flavor formation, we compared the catabolism of phenylalanine, leucine, and methionine by single strains and strain mixtures of Lactococcus lactis subsp. cremoris NCDO763 and three mesophilic lactobacilli. Amino acid catabolism was studied in vitro at pH 5.5, by using radiolabeled amino acids as tracers. In the presence of alpha-ketoglutarate, which is essential for amino acid transamination, the lactobacillus strains degraded less amino acids than L. lactis subsp. cremoris NCDO763, and produced mainly nonaromatic metabolites. L. lactis subsp. cremoris NCDO763 produced mainly the carboxylic acids, which are important compounds for cheese aroma. However, in the reaction mixture containing glutamate, only two lactobacillus strains degraded amino acids significantly. This was due to their glutamate dehydrogenase (GDH) activity, which produced alpha-ketoglutarate from glutamate. The combination of each of the GDH-positive lactobacilli with L. lactis subsp. cremoris NCDO763 had a beneficial effect on the aroma formation. Lactobacilli initiated the conversion of amino acids by transforming them mainly to keto and hydroxy acids, which subsequently were converted to carboxylic acids by the Lactococcus strain. Therefore, we think that such cooperation between starter L. lactis and GDH-positive lactobacilli can stimulate flavor development in cheese.
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Soeryapranata E, Powers JR, Fajarrini F, Weller KM, Hill HH, Siems WF. Relationship between MALDI-TOF analysis of beta-CN f193-209 concentration and sensory evaluation of bitterness intensity of aged cheddar cheese. J Agric Food Chem 2002; 50:4900-4905. [PMID: 12166979 DOI: 10.1021/jf011668f] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An internal standard method was previously developed to measure the concentration of a synthetic bitter peptide, beta-CN f193-209, by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The objective of this study was to evaluate the relationship between beta-CN f193-209 concentration in an aqueous extract of aged Cheddar cheese and bitterness intensity of the cheese. Concentrations of beta-CN f193-209 in cheese extracts were determined by MALDI-TOF at 0, 120, 180, and 270 days. Trained panels evaluated the bitterness intensity of the cheeses at 180 and 270 days. Correlation coefficients between MALDI and sensory data at 180 and 270 days were 0.803 and 0.554, respectively. The decreased correlation may be due to the presence of other bitter peptides more responsible for bitterness at longer aging or the production of compounds that mask bitterness intensity.
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Affiliation(s)
- Elly Soeryapranata
- Department of Food Science and Human Nutrition, Washington State University, P.O. Box 646376, Pullman, Washington 99164-6376, USA
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Broadbent JR, Barnes M, Brennand C, Strickland M, Houck K, Johnson ME, Steele JL. Contribution of Lactococcus lactis cell envelope proteinase specificity to peptide accumulation and bitterness in reduced-fat Cheddar cheese. Appl Environ Microbiol 2002; 68:1778-85. [PMID: 11916696 PMCID: PMC123837 DOI: 10.1128/aem.68.4.1778-1785.2002] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [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: 11/20/2022] Open
Abstract
Bitterness is a flavor defect in Cheddar cheese that limits consumer acceptance, and specificity of the Lactococcus lactis extracellular proteinase (lactocepin) is widely believed to be a key factor in the development of bitter cheese. To better define the contribution of this enzyme to bitterness, we investigated peptide accumulation and bitterness in 50% reduced-fat Cheddar cheese manufactured with single isogenic strains of Lactococcus lactis as the only starter. Four isogens were developed for the study; one was lactocepin negative, and the others produced a lactocepin with group a, e, or h specificity. Analysis of cheese aqueous extracts by reversed-phase high-pressure liquid chromatography confirmed that accumulation of alpha(S1)-casein (f 1-23)-derived peptides f 1-9, f 1-13, f 1-16, and f 1-17 in cheese was directly influenced by lactocepin specificity. Trained sensory panelists demonstrated that Cheddar cheese made with isogenic starters that produced group a, e, or h lactocepin was significantly more bitter than cheese made with a proteinase-negative isogen and that propensity for bitterness was highest in cells that produced group h lactocepin. These results confirm the role of starter proteinase in bitterness and suggest that the propensity of some industrial strains for production of the bitter flavor defect in cheese could be altered by proteinase gene exchange or gene replacement.
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Affiliation(s)
- Jeffery R Broadbent
- Western Dairy Center and Department of Nutrition and Food Sciences, Utah State University, Logan, Utah 84322-8700, USA.
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Williams A, Noble J, Tammam J, Lloyd D, Banks J. Factors affecting the activity of enzymes involved in peptide and amino acid catabolism in non-starter lactic acid bacteria isolated from Cheddar cheese. Int Dairy J 2002. [DOI: 10.1016/s0958-6946(02)00063-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
The influence of four adjunct cultures [Brevibacterium linens (BL2), Lactococcus lactis ssp. diacetylactis, Lactobacillus helveticus (LH212), and Lactobacillus reuteri (ATCC 23272)] on chemical and sensory characteristics of reduced fat Edam cheese was studied. The aminopeptidase activity of Lactococcus lactis ssp. diacetylactis was higher than that of Lactobacillus helveticus, Lactobacillus reuteri, and Brevibacterium linens, respectively. Mean percent fat and moisture contents of reduced fat cheese were 20.85 +/- 0.69 and 42.95 +/- 0.43, respectively. Percentage of fat and moisture of full fat control cheese were 30.06 +/- 0.78 and 39.11 +/- 0.60. Titratable acidity increased in all cheese with aging while pH initially decreased but increased in cheese after 6 mo aging at 7 degrees C. Lactic acid bacteria counts were on average one log higher for reduced fat cheeses than for full fat control cheese and counts decreasing with aging. Free amino acids (FAA) in cheeses increased with aging, and were higher in reduced fat cheeses than in the full fat control cheese. Reduced fat cheeses containing L. helveticus exhibited the highest FAA content. Descriptive sensory panelists (n = 9) did not detect differences among cheeses after 3 and 6 mo ripening, but aged/developed flavors (fruity, nutty, brothy, sulfur, free fatty acid) and sweetness increased between 3 and 6 mo. Expert panelists (n = 6) detected differences in texture quality among the cheeses. Reduced fat control cheeses and reduced fat cheeses with L. helveticus and L. reuteri received the highest texture quality scores. Addition of L. helveticus and Lc. lactis ssp. diacetylactis, as adjunct cultures to reduced fat Edam cheeses increased proteolysis, while the addition of L. helveticus and L. reuteri increased texture quality of cheeses.
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Affiliation(s)
- W Tungjaroenchai
- Department of Food Science and Technology, Mississippi State University, Mississippi State, MS 39762, USA
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Abstract
Attempts to develop a desirable reduced fat Cheddar cheese are impeded by a propensity for flavor defects such as meaty-brothy, putrid, fecal, and unclean off-flavors in these products. Recent studies suggest aromatic amino acid catabolism of starter, adjunct, and nonstarter lactic acid bacteria significantly impact off-flavor development. The objective of this study was to delineate pathways for catabolism of tryptophan (Trp) in Brevibacterium linens, a cheese flavor adjunct, and to determine the potential for this organism to contribute to this defect. Growth and production of aromatic compounds from Trp by B. linens BL2 were compared in two incubated conditions (laboratory and a cheese-like environment). A chemically defined medium was used to determine the cellular enzymes and metabolites involved in Trp catabolism. Trp was converted to kynurenine, anthranilic acid, and three unknown compounds in laboratory conditions. The accumulation of other unknown compounds in the culture supernatant in laboratory conditions indicated that B. linens BL2 degraded Trp by various routes. Up to 65% of Trp was converted to anthranilic acid via the anthranilic acid pathway. To assess this potential before cheese making, the cells were incubated in cheese-like conditions (15 degrees C, pH 5.2, no sugar source, 4% NaCl). Trp was not utilized by BL2 incubated in this condition. Enzyme studies using cell-free extracts of cells incubated in laboratory conditions and assayed at optimal and nonoptimal enzyme assay conditions revealed Trp transaminase (EC 2.6.1.27) was active before enzymes of the anthranilic acid pathway were detected. The products of Trp transaminase activity were not, however, found in the culture supernatant, indicating these intermediates were not exported nor accumulated by the cells. Enzymes assayed in nonoptimal conditions had considerably lower enzyme activities than found in laboratory incubation conditions. Based on these results, we hypothesize that these enzymes are not likely to be involved in the formation of compounds associated with off-flavors in Cheddar cheese.
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Affiliation(s)
- M Ummadi
- Center for Microbe Detection and Physiology, Department of Nutrition and Food Sciences, Utah State University, Logan, 84322-8700, USA
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29
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Abstract
AIMS To study the ability of Lactobacillus casei and Lact. plantarum strains to convert methonine to cheese flavour compounds. METHODS AND RESULTS Strains were assayed for methionine aminotransferase and lyase activities, and amino acid decarboxylase activity. About 25% of the strains assayed showed methionine aminotransferase activity. The presence of glucose in the reaction mixture increased conversion of methionine to 4-methylthio-2-ketobutanoate (KMBA) and 4-methylthio-2-hydroxybutanoate (HMBA) in all strains. The methionine aminotransferase activity in Lact. plantarum and Lact. casei showed variable specificity for the amino group acceptors glyoxylate, ketoglutarate, oxaloacetate and pyruvate. None of the strains showed methionine lyase or glutamate and methionine decarboxylase activities. CONCLUSION The presence of amino acid converting enzymes in lactobacilli is strain specific. SIGNIFICANCE AND IMPACT OF THE STUDY The findings of this work suggest that lactobacilli can be used as adjuncts for flavour formation in cheese manufacture.
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Affiliation(s)
- F Amarita
- Department of Dairy Science and Technology, Instituto del Frío, Ciudad Universitaria, Madrid, Spain
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30
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Abstract
Volatile sulfur compounds such as methanethiol, dimethyl disulfide, dimethyl trisulfide, and hydrogen sulfide constitute an important fraction of Cheddar cheese flavor. These compounds are products of the catabolism of methionine and cysteine by bacteria in the cheese matrix. The objectives of this study were to examine the levels and types of volatile sulfur compounds produced from methionine by lactic acid bacteria frequently used in cheese making and to investigate cystathionine degrading activity, which may be responsible for the liberation of these compounds. Gas chromatography with headspace sampling was used to determine volatile sulfur compounds (VSC) produced by whole cells of 24 strains of lactobacilli and 13 strains of lactococci incubated with methionine. Total VSC production varied widely in the species and subspecies tested. Nearly all strains produced VSC from methionine, but the enzyme responsible for this activity remains unclear. Cystathionine-degrading ability and the effect of methionine concentration on this ability of some of the strains was investigated. Increasing the concentrations of methionine inhibited the cystathionine-degrading ability of lactococci, but not of lactobacilli. Lactococci were found to require methionine for growth, while lactobacilli required both methionine and cysteine. Because of the low level of cystathionine-degrading activity in lactobacilli and the inhibition of this activity by methionine in lactococci, VSC production is likely due to enzymes other than cystathionine beta- and gamma-lyase in whole cells.
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Affiliation(s)
- K E Seefeldt
- Center for Microbe Detection and Physiology, Western Dairy Center, Department of Nutrition and Food Sciences, Utah State University, Logan 84322-8700, USA
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31
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Abstract
There have been important milestones in biotechnological practice that have led to the determination and production of superior cheese flavours. Within the past year, the use of gas chromatographic techniques and sensory methodologies has been optimised by several groups in efforts to evaluate the organoleptic properties of a number of mature cheeses. The hydrolysis of milk caseins, small peptides, free amino acids and fatty acids, and the generation of sulfur-containing compounds are uniformly assumed to result in the formation of specific cheese aromas. Giant strides have been taken in molecular technology to aid the dissection and exploitation of the metabolic pathways that lead to the formation of these flavour constituents. Specific advances in molecular technology have included metabolic engineering of lactic acid bacteria for enhanced flavour development.
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Affiliation(s)
- A Forde
- Department of Microbiology, National Food Biotechnology Centre, University College, Cork, Ireland
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32
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Chavagnat F, Meyer J, Casey MG. Purification, characterisation, cloning and sequencing of the gene encoding oligopeptidase PepO from Streptococcus thermophilus A. FEMS Microbiol Lett 2000; 191:79-85. [PMID: 11004403 DOI: 10.1111/j.1574-6968.2000.tb09322.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [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: 11/27/2022] Open
Abstract
The oligopeptidase PepO from Streptococcus thermophilus A was purified to protein homogeneity by a five-step chromatography procedure. It was estimated to be a serine metallopeptidase of 70 kDa, with maximal activity at pH 6.5 and 41 degrees C. PepO has endopeptidase activity on oligopeptides composed of between five and 30 amino acids. PepO was demonstrated to be active and stable at the pH, temperature and salt concentrations found in Swiss-type cheese during ripening. Using a battery of PCR techniques, the pepO gene was amplified, subcloned and sequenced, revealing an open reading frame of 1893 nucleotides. The amino acid sequence analysis of the pepO gene-translation product shows homology with PepO enzymes from other lactic acid bacteria and contains the signature sequence of the metallopeptidase family.
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Affiliation(s)
- F Chavagnat
- Department of Microbiology, Swiss Dairy Research Institute, Liebefeld, CH-3003, Bern, Switzerland.
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33
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Abstract
Several previous reviews have described different ways to enhance the flavor and texture of cheese, including use of live cells and nonviable attenuated cells as adjunct cultures. However, comparisons between viable and nonviable cultures were never discussed in these reviews. In addition, recent publications on adjunct cultures have not been covered in previous reviews. This article will survey the more recent work on adjunct cultures--with particular attention to whether the adjuncts contained viable or nonviable cells--and propose areas where additional research is needed.
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Affiliation(s)
- M El Soda
- Department of Dairy Science and Technology, Faculty of Agriculture, Alexandria University, Egypt
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34
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Gobbettia M, Lanciotti R, De Angelis M, Rosaria Corbo M, Massini R, Fox P. Study of the effects of temperature, pH, NaCl, and aw on the proteolytic and lipolytic activities of cheese-related lactic acid bacteria by quadratic response surface methodology. Enzyme Microb Technol 1999. [DOI: 10.1016/s0141-0229(99)00110-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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35
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Gobbetti M, Lanciotti R, De Angelis M, Rosaria Corbo M, Massini R, F. Fox P. Study of the effects of temperature, pH and NaCl on the peptidase activities of non-starter lactic acid bacteria (NSLAB) by quadratic response surface methodology. Int Dairy J 1999. [DOI: 10.1016/s0958-6946(99)00156-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [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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36
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Drake M, Karagül-yüceer Y, Chen X, Cadwallader K. Characterization of Desirable and Undesirable Lactobacilli from Cheese in Fermented Milk. Lebensm Wiss Technol 1999; 32:433-9. [DOI: 10.1006/fstl.1999.0572] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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38
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Abstract
Physicochemical and microbiological parameters were compared for three brining times (12, 24 and 36 h) for fresh, young, semihard and hard Idiazabal cheese. Longer brining time produced higher salt, dry matter and salt-moisture ratio and lower water activity values for all types of cheese according to ripening time, while non-significant changes were observed for pH. In fresh cheese (1-15 days ripening), non-significant differences for microbiological counts in relation to brining time were observed, except for moulds. In young and hard cheeses, Lactobacillus and Leuconostoc showed lower counts with longer brining times. In contrast, Micrococaceae, yeast and moulds were stimulated by higher salt content in matured cheeses. In addition. this work has proved that there are lower water activity values and lower microbiological counts in longer-matured Idiazabal cheeses. For the different brining and ripening times, positive correlations were observed among most of the microbial groups studied, but a different behavior was established for Enterococcus, Clostridium tyrobutyricum, yeast and moulds.
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Affiliation(s)
- F J Pérez Elortondo
- Facultad de Farmacia, Area de Nutrición y Bromatología, Universidad del País Vasco/Euskal Herriko Unibersitatea, Paseo de la Universidad, Vitoria-Gasteiz, Spain.
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40
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Chavagnat F, Casey MG, Meyer J. Purification, characterization, gene cloning, sequencing, and overexpression of aminopeptidase N from Streptococcus thermophilus A. Appl Environ Microbiol 1999; 65:3001-7. [PMID: 10388695 PMCID: PMC91448 DOI: 10.1128/aem.65.7.3001-3007.1999] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/1998] [Accepted: 04/09/1999] [Indexed: 11/20/2022] Open
Abstract
The general aminopeptidase PepN from Streptococcus thermophilus A was purified to protein homogeneity by hydroxyapatite, anion-exchange, and gel filtration chromatographies. The PepN enzyme was estimated to be a monomer of 95 kDa, with maximal activity on N-Lys-7-amino-4-methylcoumarin at pH 7 and 37 degrees C. It was strongly inhibited by metal chelating agents, suggesting that it is a metallopeptidase. The activity was greatly restored by the bivalent cations Co2+, Zn2+, and Mn2+. Except for proline, glycine, and acidic amino acid residues, PepN has a broad specificity on the N-terminal amino acid of small peptides, but no significant endopeptidase activity has been detected. The N-terminal and short internal amino acid sequences of purified PepN were determined. By using synthetic primers and a battery of PCR techniques, the pepN gene was amplified, subcloned, and further sequenced, revealing an open reading frame of 2,541 nucleotides encoding a protein of 847 amino acids with a molecular weight of 96,252. Amino acid sequence analysis of the pepN gene translation product shows high homology with other PepN enzymes from lactic acid bacteria and exhibits the signature sequence of the zinc metallopeptidase family. The pepN gene was cloned in a T7 promoter-based expression plasmid and the 452-fold overproduced PepN enzyme was purified to homogeneity from the periplasmic extract of the host Escherichia coli strain. The overproduced enzyme showed the same catalytic characteristics as the wild-type enzyme.
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Affiliation(s)
- F Chavagnat
- Department of Biochemistry, Swiss Dairy Research Institute, 3097 Liebefeld-Bern, Switzerland.
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41
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Abstract
Brevibacterium linens is a major surface microorganism that is present in the smear of surface-ripened cheeses. The enzymology and biochemical characteristics of B. linens influence the ripening and final characteristics of smear surface-ripened cheeses. Proteolytic, peptidolytic, esterolytic, and lipolytic activities, which are of particular importance in the ripening process, are discussed in detail. This review also describes the production of volatile compounds, especially sulfur-containing ones, by B. linens, which are thought to be important in respect to the flavor of smear surface-ripened cheeses. The unique orange-colored carotenoids and the factors effecting their production by B. linens are also presented. The catabolism of aromatic amino acids, bacteriocin production, plasmids, and miscellaneous biochemical and physiological properties (peptidoglycan type, antibiotic resistance, insecticide degradation, and biotechnological applications) of B. linens are discussed. The problem associated with the current taxonomical classification of B. linens strains caused by strain variation is evaluated. Finally, the application of B. linens cell extracts or its proteolytic enzymes as cheese ripening accelerants for semi-hard or hard cheese varieties is considered.
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Affiliation(s)
- F P Rattray
- Department of Food Chemistry, University College, Cork, Ireland
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Stuart MR, Chou LS, Weimer BC. Influence of carbohydrate starvation and arginine on culturability and amino acid utilization of lactococcus lactis subsp. lactis. Appl Environ Microbiol 1999; 65:665-73. [PMID: 9925598 PMCID: PMC91077 DOI: 10.1128/aem.65.2.665-673.1999] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two strains of Lactococcus lactis subsp. lactis were used to determine the influence of lactose and arginine on viability and amino acid use during carbohydrate starvation. Lactose provided energy for logarithmic-phase growth, and amino acids such as arginine provided energy after carbohydrate exhaustion. Survival time, cell numbers, and ATP concentrations increased with the addition of arginine to the basal medium. By the onset of lactose exhaustion, the concentrations of glycine-valine and glutamate had decreased by as much as 67% in L. lactis ML3, whereas the serine concentration increased by 97% during the same period. When no lactose was added, the concentrations of these amino acids remained constant. Similar trends were observed for L. lactis 11454. Without lactose or arginine, L. lactis ML3 was nonculturable on agar but was viable after 2 days, as measured by fluorescent viability stains and intracellular ATP levels. However, L. lactis 11454 without lactose or arginine remained culturable for at least 14 days. These data suggest that lactococci become viable but nonculturable in response to carbohydrate depletion. Additionally, these data indicate that amino acids other than arginine facilitate the survival of L. lactis during carbohydrate starvation.
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Affiliation(s)
- M R Stuart
- Western Dairy Center, Center for Microbe Detection & Physiology, Department of Nutrition and Food Sciences, Utah State University, Logan, Utah 84322-8700, USA
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43
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Abstract
Methanethiol has been strongly associated with desirable Cheddar cheese flavor and can be formed from the degradation of methionine (Met) via a number of microbial enzymes. Methionine gamma-lyase is thought to play a major role in the catabolism of Met and generation of methanethiol in several species of bacteria. Other enzymes that have been reported to be capable of producing methanethiol from Met in lactic acid bacteria include cystathionine beta-lyase and cystathionine gamma-lyase. The objective of this study was to determine the production, stability, and activities of the enzymes involved in methanethiol generation in bacteria associated with cheese making. Lactococci and lactobacilli were observed to contain high levels of enzymes that acted primarily on cystathionine. Enzyme activity was dependent on the concentration of sulfur amino acids in the growth medium. Met aminotransferase activity was detected in all of the lactic acid bacteria tested and alpha-ketoglutarate was used as the amino group acceptor. In Lactococcus lactis subsp. cremoris S2, Met aminotransferase was repressed with increasing concentrations of Met in the growth medium. While no Met aminotransferase activity was detected in Brevibacterium linens BL2, it possessed high levels of L-methionine gamma-lyase that was induced by addition of Met to the growth medium. Met demethiolation activity at pH 5.2 with 4% NaCl was not detected in cell extracts but was detected in whole cells. These data suggest that Met degradation in Cheddar cheese will depend on the organism used in production, the amount of enzyme released during aging, and the amount of Met in the matrix.
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44
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Abstract
L-Methionine gamma-lyase (EC 4.4.1.11) was purified to homogeneity from Brevibacterium linens BL2, a coryneform bacterium which has been used successfully as an adjunct bacterium to improve the flavor of Cheddar cheese. The enzyme catalyzes the alpha,gamma elimination of methionine to produce methanethiol, alpha-ketobutyrate, and ammonia. It is a pyridoxal phosphate-dependent enzyme, with a native molecular mass of approximately 170 kDa, consisting of four identical subunits of 43 kDa each. The purified enzyme had optimum activity at pH 7.5 and was stable at pHs ranging from 6.0 to 8.0 for 24 h. The pure enzyme had its highest activity at 25 degreesC but was active between 5 and 50 degreesC. Activity was inhibited by carbonyl reagents, completely inactivated by DL-propargylglycine, and unaffected by metal-chelating agents. The pure enzyme had catalytic properties similar to those of L-methionine gamma-lyase from Pseudomonas putida. Its Km for the catalysis of methionine was 6.12 mM, and its maximum rate of catalysis was 7.0 &mgr;mol min-1 mg-1. The enzyme was active under salt and pH conditions found in ripening Cheddar cheese but susceptible to degradation by intracellular proteases.
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45
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Broadbent JR, Strickland M, Weimer BC, Johnson ME, Steele JL. Peptide Accumulation and Bitterness in Cheddar Cheese Made Using Single-Strain Lactococcus lactis Starters with Distinct Proteinase Specificities. J Dairy Sci 1998. [DOI: 10.3168/jds.s0022-0302(98)75581-x] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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