The effect of microbial lipase on the lipolysis during the ripening of Tulum cheese

Preparation of pH-responsive chitosan microspheres containing aminopeptidase and their application in accelerating cheese ripening

Microencapsulated enzymes have been found to effectively accelerate cheese ripening. However, microencapsulated enzyme release is difficult to control, often resulting in enzyme release during cheese processing and causing texture and flavor defects. This study aims to address this issue by developing aminopeptidase-loaded pH-responsive chitosan microspheres (A-CM) for precise enzyme release during cheese ripening. An aminopeptidase with an isoelectric point (pH 5.4) close to the pH value of cheese ripening was loaded on chitosan microspheres through electrostatic interaction. Turbidity titration measurements revealed that pH 6.5 was optimal for binding aminopeptidase and microspheres, affording the highest loading efficiency of 58.16%. Various characterization techniques, including scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier-transform infrared spectroscopy confirmed the successful loading of aminopeptidase molecules on the chitosan microspheres. In vitro release experiments conducted during simulated cheese production demonstrated that aminopeptidase release from A-CM was pH responsive. The microspheres retained the enzyme during the coagulation and cheddaring processes (pH 5.5-6.5) and only released it after entering the cheese-ripening stage (pH 5.0-5.5). By loading aminopeptidase on chitosan microspheres, the loss rate of the enzyme in cheese whey was reduced by approximately 79%. Furthermore, compared with cheese without aminopeptidase and cheese with aminopeptidase added directly, the cheeses made with A-CM exhibited the highest proteolysis level and received superior sensory ratings for taste and smell. The content of key aroma substances, such as 2/3-methylbutanal and ethyl butyrate, in cheese with A-CM was more than 15 times higher than the others. This study provides an approach for accelerating cheese ripening through the use of microencapsulated enzymes.

The influence of ripening of semi-hard goat cheese in oil on its physicochemical composition and sensory properties

The aim of this paper was to determine the influence of ripening of semi-hard goat cheese in oil (mixture of Mljet's extra-virgin olive oil and refined sunflower oil; 50:50) on its physicochemical composition and sensory properties, as well as to determine the optimal time of immersion of the cheese in oil. Five batches of cheeses were produced, and the cheeses of the same batch were randomly divided into 3 groups according to the ripening method: (1) ripening in air (control group, treatment 1), (2) ripening in oil after 10 d of ripening in air (treatment 2), (3) ripening in oil after 20 d of ripening in air (treatment 3). Cheeses were sampled during ripening at d 0, 10, 20, 30, 45, and 60, and physicochemical analyses were performed. Oil as a ripening medium for cheese prevented water loss from the cheese (groups 2 and 3), and the significantly lowest contents of dry matter, protein, fat, saturated fatty acids (SFA), unsaturated fatty acids (UFA), oleic acid, and salt were found in group 2. Group 3 had the highest contents of fat, SFA, UFA, and oleic acid. Prolonged ripening of the cheese in air before immersion in oil resulted in greater water loss and the formation of such cheese structure that allowed oil to penetrate the cheese. Water retention and oil penetration into the cheese altered the physicochemical composition of the goat cheese, having a significantly positive effect on the sensory characteristics, particularly color, texture, and taste, allowing the cheese to be consumed even when goat milk is not produced due to seasonality.

Effects of the Autochthonous Probiotic Bacteria Lactobacillus plantarum B and Lactococcus lactis Subsp. lactis S1 on the Proteolysis of Croatian Cheese Ripened in a Lambskin Sack (Sir iz Mišine)

This study aims to determine the effects of the autochthonous probiotic bacteria Lactobacillus plantarum B (currently Lactiplantibacillus plantarum) and Lactococcus lactis subsp. lactis S1 on proteolysis during the ripening of Sir iz mišine—a Croatian cheese which ripens in a lambskin sack. Sir iz mišine was produced in four different variants: (1) from raw milk without starter cultures, and from pasteurized milk with added (2) Lactococcus lactis ssp. lactis S1, (3) Lactobacillus plantarum B, or (4) a starter culture consisting of a mixture of Lactococcus lactis ssp. lactis S1 and Lactobacillus plantarum B (1:1). The addition of Lactobacillus plantarum B alone or in combination with Lactococcus lactis subsp. lactis S1 noticeably increased the alpha and beta indices because of the synergistic activity between the enzymes responsible for primary proteolysis and added autochthonous bacteria. Cheese produced from raw milk had the lowest (12.16%) content of WSN%TN. The highest WSN%TN content was found in cheese produced with combined probiotic bacteria (30.40%) and Lactococcus lactis ssp. lactis S1 (29.74%). Cheese with added combined probiotic bacteria had a noticeably higher content of TCA-SN%TN, indicating a synergistic performance among autochthonous probiotic bacteria. In conclusion, autochthonous probiotic bacteria, in addition to having a functional value, can improve the ripening properties of cheese.

Effect of microbial lipase and transglutaminase on the textural, physicochemical, and microbial parameters of fresh quark cheese

In this study, the addition of microbial transglutaminase (MTG) and lipase in quark cheese samples was studied during storage (21 d). Four types of cheese were made using 3 different levels of MTG (T1, 0.1 g/L; T2, 0.2 g/L; T3, 0.3 g/L) and lipase (T1, 0.02 g/L; T2, 0.04 g/L; T3, 0.06 g/L), and one cheese was made without any treatment as a control sample. The physicochemical, textural, microbial, and sensory properties of cheese samples were monitored at 1, 7, 14, and 21 d of storage period. The results showed that the treated samples had higher proteolysis and lipolysis activities during storage than the control sample. The textural analysis indicated an insignificant increase in the hardness value of the enzyme-treated sample. Also, the sensory analysis exhibited that the treated samples had higher texture acceptability. The higher concentration of enzymes resulted in lower color, odor, taste, and overall acceptability, and higher microbial population. Finally, the addition of microbial MTG and lipase in preparation of quark cheese samples could be recommended for a short storage time.

The effects of packaging materials on the fatty acid composition, organic acid content, and texture profiles of Tulum cheese

In this research, Erzincan Tulum cheese was packaged in its original packaging material, the skin bag, small intestine, and appendix to observe the changes in its physical, chemical, and textural properties during storage day. Lactic acid% values increased in all Tulum cheeses throughout storage stage. At the end of the storage period, the highest value was determined in the sample filled in the small intestine (20.10%). All fatty acid values were increased, and the highest increase was identified in oleic acid (C 18:1) (skin bag 2.18%), linoleic acid (18:2) (appendix 0.41%), and palmitic acid (C 16:0) (small intestine 0.34%), respectively. All organic acids increased in stored sample. The highest increase among organic acids was determined to be 4.47% in lactic acid. As a result of the Texture Profile Analyses (TPA), the hardness, and adhesiveness of Tulum cheeses increased during storage periods, whereas the springiness, cohesiveness, and chewiness values decreased. Gumminess value declined in the sample filled into the appendix (with a value of 36.01), whereas it increased in the other two samples. The highest increase in hardness values was 2,520.27 N at given storage time was in the samples filled into appendix while the highest adhesive values of -49.82 were determined in the sample filled into small intestine. PRACTICAL APPLICATION: Tulum cheese is usually produced by filling sheep or goat skin bag. Goat or sheep skin bag are not always available, and the amount of cheese produced in them is excessive. Therefore, cheeses were also filled to small intestine and appendix. At the end of the study, there were no negative effects on cheeses filled with intestine and appendix. The use of small intestine and appendix has helped to develop a product that will be appreciated by the consumers with no adverse effects in the physicochemical and textural properties of cheese.

Diversity of non-starter lactic acid bacteria in autochthonous dairy products from Western Balkan Countries - Technological and probiotic properties

The aim of this review was to summarize the data regarding diversity of non-starter lactic acid bacteria (NSLAB) isolated from various artisanal dairy products manufactured in Western Balkan Countries. The dairy products examined were manufactured from raw cow's, sheep's or goat's milk or mixed milk, in the traditional way without the addition of commercial starter cultures. Dairy products such as white brined cheese, fresh cheese, hard cheese, yogurt, sour cream and kajmak were sampled in the households of Serbia, Croatia, Slovenia, Bosnia and Herzegovina, Montenegro, and North Macedonia. It has been established that the diversity of lactic acid bacteria (LAB) from raw milk artisanal dairy products is extensive. In the reviewed literature, 28 LAB species and a large number of strains belonging to the Lactobacillus, Lactococcus, Enterococcus, Streptococcus, Pediococcus, Leuconostoc and Weissella genera were isolated from various dairy products. Over 3000 LAB strains were obtained and characterized for their technological and probiotic properties including: acidification and coagulation of milk, production of aromatic compounds, proteolytic activity, bacteriocins production and competitive exclusion of pathogens, production of exopolysaccharides, aggregation ability and immunomodulatory effect. Results show that many of the isolated NSLAB strains had one, two or more of the properties mentioned. The data presented emphasize the importance of artisanal products as a valuable source of NSLAB with unique technological and probiotic features important both as a base for scientific research as well as for designing novel starter cultures for functional dairy food.

Acceleration of Swiss cheese ripening by microbial lipase without affecting its quality characteristics

The effect of exogenous microbial lipase enzyme on the ripening of Swiss cheese (0, 200, and 800U lipase in 30 L milk) was investigated for the physico-chemical, textural and sensory properties, along with its microstructure. The aim of this study was to investigate the application of microbial lipase to accelerate the ripening without affecting its original desirable quality characteristics. The effect of the microbial lipase was studied at different time periods (2, 30, 45, and 60 days) of the Swiss cheese ripening stages. Statistical analysis of the results showed that the physico-chemical parameters of cheese slightly increased during the ripening. Also, at all stages of the ripening hardness of Swiss cheese increased while the brittleness decreased. The number and size of the fat globules were also affected by the addition of the lipases. This study also showed that increase in the lipase amount had no significant change in quality and sensory parameters. Therefore, 200U of lipase was found to be sufficient to reduce the ripening time from 90 to 60 days by maintaining its genuine quality. Thus, this study suggested that the addition of microbial lipase may significantly reduce the cost of the cheese production by lowering the ripening period by 1 month and maintaining the quality of the final product.

Effects of High Pressure Treatments on the Ripening of Hard Cheeses

The effects of high-pressure (HP) treatments (200, 300, 400 and 500MPa for 10 min, 2P to 5P) applied on day 1 to accelerate the ripening of hard cheeses. The proteolysis, lipolysis, texture and sensory properties were studied in 90 days at 10°C. HP treatments increased proteolysis and sensory properties at all stages of ripening in all treated cheeses, furthermore, higher hydrolysis and sensory properties were found in 3P cheeses. However, HP treatments had no positive effects on cheeses lipolysis development, especially, in 5P cheeses.

Influence of lamb rennet paste on the lipolytic and sensory profile of Murcia al Vino cheese

The influence of lamb rennet paste (71.1% chymosin, 177 international milk-clotting units/mL, 4.57U/g of lipase activity) during the ripening of Murcia al Vino goat cheese was studied. The aim of this study was to improve the knowledge of the effect of lamb rennet paste on the lipolytic patterns in this type of cheese by reference to the evolution of total and free fatty acids. A sensory analysis was carried out to compare cheeses made with commercial and paste rennet. The rennet paste showed higher lipolytic activity, enhancing the production of short-chain free fatty acids. In addition, the cheese produced with lamb rennet paste had a slightly more bitter and piquant taste, making it an attractive commercial alternative that can be used to develop new varieties of goat cheese.

Effects of frozen storage and vacuum packaging on free fatty acid and volatile composition of Turkish Motal cheese

Effects of vacuum packaging and frozen storage were studied on the formation of free fatty acids (FFAs), volatile compounds and microbial counts of Motal cheese samples stored for a period of 180 days. The FFA concentration of Motal cheese samples increased throughout the storage period of 180 days. However, the FFA contents of samples stored at —18 °C showed considerably lower values than those of the samples stored at 4 °C. Palmitic (C16:0) and oleic (C18:1) acids were the most abundant FFAs in all the treatments. The volatile compounds detected by headspace solid-phase microextraction (HS-SPME) profile of Motal cheese consisted of 16 esters, 10 acids, 6 ketones, 4 alcohols, 3 aldehydes, styrene, p-cresol and m-cresol. Results showed that storage at —18 °C can limit the excessive volatile compound formation. Samples stored at 4°C with vacuum packaging showed comparatively high concentration of esters, ketones and alcohols. Samples stored without vacuum packaging at 4°C showed 2-nonanone as the most abundant volatile compound toward the end of storage period. Storage at 4°C under vacuum packaging decreased the mold—yeast counts of samples. Frozen storage could be a suitable method for storing the Motal cheese.

Trace metal levels and some chemical parameters in herby cheese collected from south eastern Anatolia-Turkey

Due to the consumption of the herby cheese in south eastern Anatolia-Turkey is at high ratio, chemical parameters such as dry matter, pH, acidity, aCl, protein, fat and trace metal contents in 50 different herby cheeses produced at this region have been determined in the presented study. The content of lead, copper, cobalt, nickel, chromium, cadmium, and iron have been analyzed by flame atomic absorption spectrometer in air/acetylene flame after combination ash digestion method and wet digestion method. The mean concentration of lead, copper, cobalt, nickel, chromium and cadmium in our samples are higher than literature values except iron.

Microbiology, Biochemistry, and Volatile Composition of Tulum Cheese Ripened in Goat's Skin or Plastic Bags

Tulum cheeses were manufactured from raw ewe's milk and ripened in goat's skin bags (tulums) or plastic containers to understand the effect of ripening container on the chemical composition, biochemistry, microbiology, and volatile composition of Tulum cheeses during 150 d of ripening. Chemical compositions of the cheeses ripened in tulums were significantly different and the moisture contents decreased rapidly in those cheeses because of the porous structure of the tulum. Higher microbial counts were detected in the cheeses ripened in plastic than in cheeses ripened in tulums. Differences in nitrogenous compounds and total free AA of the cheeses were not significant. Total concentrations of free AA in cheeses increased with age and Glu, Ala, Val, Leu, and Phe were the most abundant AA in the cheeses. Urea-PAGE of pH 4.6-insoluble fractions of the cheeses during ripening showed similar degradation patterns in all cheeses. Peptide profiles by reversed-phase HPLC of pH 4.6- and ethanol-soluble or ethanol-insoluble fractions of the cheeses revealed only minor differences in the concentrations of some peptides among the cheeses; however, age-related changes in peptide concentrations were significantly different among the cheeses. Cheeses were analyzed at 90 d of ripening for volatile compounds by solid-phase microextraction gas chromatography-mass spectrometry. One hundred volatile components were identified, including 11 acids, 16 esters, 12 methyl ketones, 7 aldehydes, 22 alcohols, 7 sulfur compounds, 6 terpenes, and 19 miscellaneous compounds. The main components were short-chain fatty acids, 2-butanone, diacetyl, and primary alcohols. Quantitative differences in several volatile compounds were evident among the cheeses. Cheeses ripened in tulums or plastic had similar aroma patterns, but the concentrations of some components were different.