EFFECT OF LIPASE ENZYME ON THE RIPENING OF WHITE PICKLED CHEESE

The effect of addition of pregastric lipase enzyme on the accelerated ripening of white pickled cheese was investigated. Commercial pregastric lipase was added to milk before rennet addition at a level of 0,5, 8, 11 g per 100 L of milk and cheeses were made from this milk. Total solids, fat, total nitrogen, salt, titratable acidity, pH and free fatty acids (C₂-C_18:1) were analysed in the samples during 1–90 days of ripening period at 15 days intervals. Total solids, fat, total nitrogen, salt, titratable acidity, and pH of cheeses slightly increased during the ripening period. Free fatty acids and volatile free fatty acid contents in cheeses made from pregastric lipase added milk were affected by pregastric lipase and their contents were increased significantly (P<0.01) during the ripening period. Particularly, when cheese had a high level (11 g per 100 L milk) pregastric lipase, the amounts of butyric, caproic and caprylic acids in white pickled cheese were quite high. The relative amounts of volatile free fatty acids varied with storage time and pregastric lipase levels.     

The effects of carbon dioxide addition to cheese milk on the microbiological properties of Turkish White brined cheese

This study invest0igated the effect of CO₂ added to achieve three pH levels: pH 6.1, pH 6.2 and pH 6.3 for treatments X, Y, Z, respectively, on some microbiological properties of Turkish White (TW) brined cheese. For each pH, four batches of cheese were produced from: raw milk with no added carbon dioxide (UR), raw milk with carbon dioxide (TR), pasteurised milk with no carbon dioxide addition (UP) and pasteurised milk with carbon dioxide addition (TP). The microbiological analysis of TW brined cheeses was carried out for 90 days of maturation period. Total aerobic mesophilic bacteria, mesophilic lactic acid bacteria, yeasts and moulds and coliform group were determined in control and CO₂ treatment groups. Mesophilic bacteria count was determined as 5.14, 5.29, 5.67 log cfu/g for pH 6.1, 6.2 and 6.3, respectively, in CO₂‐treated raw milk cheeses. Yeasts and moulds reduction increased significantly by applying CO₂ (P < 0.01). For TW cheese samples, the most significant microbial inactivation was detected at sample groups of pH 6.1.     

THE LACTIC ACID FERMENTATION OF THREE DIFFERENT GRAPE LEAVES GROWN IN TURKEY

Leaves of three different cultivars of Vitis vinifera L., Ekşikara, Hesapali and Siyah pekmezlik were fermented in 10% brine and 10% brine + 1% citric acid concentration for 5 weeks. Percent dry matter, average weight, protein and dimethyl sulfide content of fresh leaves were determined. During the fermentation time, chemical properties of brine (titratable acidity, pH, salt content) were determined at certain intervals. Fresh leaves of Ekşikara had the highest amount of dry matter (31.69%), followed by Siyah pekmezlik (27.89%) and Hesapali (25.36%).The protein content of fresh leaves decreased approximately 50% as a result of the fermentation. Fermented Hesapali leaves had the highest (2,955 kcal/100 g), while Siyah pekmezlik leaves had the lowest (2,384 kcal/100 g) energy values. Ekşikara leaves in 10% brine + 1% citric acid had the lowest pH value (2.09), while Siyah pekmezlik had the highest pH value (2.57) on the fifth week of the fermentation. The highest titratable acidity was measured in Hesapali (10% brine + 1% citric acid). Hesapali leaves in both types of brine showed the highest taste scores, while Ekşikara leaves were preferred for their more acceptable odor. Siyah pekmezlik leaves are not recommended for brining as the fermented leaves of this cultivar obtained the lowest sensory scores.     

The effects of starter culture on chemical composition, microbiological and sensory characteristics of Turkish Kaşar Cheese during ripening

Kaşar cheese samples were produced from raw milk and starter culture-added pasteurized milk. Chemical, microbiological and organoleptic properties of kaşar cheeses were analysed at certain times during the ripening periods (on the 1st, 7th, 15th, 30th, 60th, 90th days). Generally, chemical parameters were not affected by starter culture. The pH, ripening index, water-soluble nitrogen and non-protein nitrogen did not show significant differences between the cheese samples. The addition of starter affected the microbiological quality of the cheeses. Starter culture-added kaşar cheeses contained low levels of total aerobic mesophilic bacteria, moulds and yeasts, and coliforms, and achieved higher organoleptic scores than those of cheeses made from raw milk. The starter cultures contributed to acidity and microbial quality of the cheese.     

The effect of pasteurisation temperature on the CLA content and fatty acid composition of white pickled cheese

In this study, the effect of pasteurisation temperature on fatty acid composition of cheese was investigated. The fatty acid composition of raw and different heat‐treated milk, salt and salt‐free cheese were determined using cheese made from raw milk at temperatures varying between 70 and 90°C for 5 min. Generally, C 16:0 palmitic acid was the major fatty acid present in all milk and cheese samples. C 18:1 t11 vaccenic acid was the major trans fatty acid (TFA) in all samples. C 18:2 cis‐9, trans‐11 (Rumenic acid) was the major CLA isomer in these samples. Pasteurisation temperatures had no effect on TFA, CLA and fatty acid composition of the milk and cheese samples.     

A note on control system model simplification

A computer-oriented procedure for the simplification of control systems models for an algebraic method of systems design is presented. The accuracy and simplicity of the algorithm are illustrated. The proposed procedure greatly enhances the practical usefulness of various algegraic design techniques.     

Effects of sunflower honey on the physicochemical,microbiological and sensory characteristics in set type yoghurt during refrigerated storage

The primary purpose of this research was to monitor the influence of sunflower honey addition (2%, 4% and 6% w/v) to yoghurt milk on survival of the microbial flora of yoghurt and the physicochemical and sensory characteristics during refrigerated storage for 4 weeks. The water activity decreased according to the addition of honey with higher concentrations in the storage period (4°C). At the end of fermentation, pH values of yoghurt samples ranged between 4.33 (without honey) and 4.52 (addition of honey with 6%). The highest water holding capacity, consistency and the lowest brightness values were determined in the groups produced with 6% honey addition. The water holding capacity and a* (redness) values of the honey incorporated yoghurt samples increased during storage. Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus values of the yoghurt with honey increased compared with the control group samples (P < 0.01). Addition of honey to yoghurt milk has affected the vitality of the characteristics starters in the incubation and storage time of the yoghurt samples (P < 0.01). Optimum sweetness was obtained with the samples containing 4% honey level.     

Influence of different exopolysaccharide-producing strains on the physicochemical, sensory and syneresis characteristics of reduced-fat stirred yoghurt

Reduced-fat stirred yoghurts were prepared by using ropy and nonropy exopolysaccharide (EPS)-producing strains or nonexopolysaccharide-producing strains. Yoghurts were evaluated for pH, titrable acidity, acetaldehyde, whey separation, viscosity, EPS concentration, sensory and microbiological analyses. Determinations of these parameters were made at 1, 7, 14 and 21 days of storage. Reduced-fat yoghurts made with EPS⁺ strains exhibited lower syneresis and acetaldehyde contents, but higher viscosity than those made with the EPS ⁻ strain. Physico-chemical results correlated with the sensory results in that panellists scored the EPS⁺ yoghurts as having an overall better mouthfeel, but a worse flavour than EPS ⁻ yoghurt.     

BUTTER STABILITY AS AFFECTED BY EXTRACTS OF SAGE, ROSEMARY AND OREGANO

Effects of methanolic extracts of sage ( Salvia fruticosa L.), rosemary ( Rosmarinus officinalis L.) and oregano ( Origanum vulgare L.) on butter stability were investigated. All extracts were individually added to butter at 0.02 or 0.05%. For comparison, 0.02% butylated hydroxyanisole (BHA) and control group were also prepared and tested. The samples were stored at 25 or 5C. The peroxide value, free fatty acids and thiobarbituric acid value were determined at regular intervals for all samples. Spice extracts and their combinations exhibited a better effect than that of BHA in stabilizing butter against oxidation. The most effective extract was that of sage. The extracts significantly stabilized butter (P<0.05). Butter samples stored at 5C were more stable (P<0.05) than those kept at 25C.