Cow's Milk Cheese Research Articles

Cholesterol contents of U.S. and imported goat milk cheeses as quantified by different colorimetric methods

Cholesterol concentrations of 15 varieties of U.S. and imported commercial goat milk cheeses were evaluated by different extraction and colorimetric determination procedures. The majority of the caprine milk cheeses were high moisture containing soft type varieties, where moisture contents of the products were not exactly equated with cholesterol contents. The range of cholesterol levels (wet basis) in the experimental cheeses was 80–147 mg/100 g. Cholesterol contents of Texas Chevre, U.S. goat milk Gouda, and white hard goat cheeses were: 120.8, 124.8, and 95.4 mg/100 g cheese on a wet basis, and 39.3, 71.5, and 59.2 mg/100 g on a dry basis, respectively. On a wet basis, the Texas Chevre with pepper and herbs variety had the lowest (80.9 mg/100 g), while the imported variety of Royal Province with garlic and herbs contained the greatest amount of cholesterol (146.8 mg/100 g). However, cheese with the highest dry matter (Norwegian Gjetost) showed the greatest cholesterol (107.0 mg/100 g) among all tested goat cheese varieties on a dry basis. Cholesterol in goat milk cheeses of this study determined by the colorimetric method was higher than in cow milk cheeses determined by the gas chromatographic (GC) method in previous reports. It was concluded that the differences in cholesterol between goat and cow milk cheeses may be attributable to the differences in analytical procedure rather than species of milk or cheese, because cow milk reportedly contains slightly higher cholesterol than goat milk. The turbidity of the sample solution in colorimetric procedures might also be partially accountable for differences in cholesterol among different varieties especially in spice added cheeses. The colorimetric method using o-phthalaldehyde was more consistent and about 20% less variable than using FeSO 4-acetic acid as the color developing agent in the determination of cholesterol.

Développement des caractéristiques biochimiques et sensorielles des fromages de chèvre. Étude interespèce par échange de la matière grasse et du lait écrémé de laits de vache et de chèvre

Development of biochemical and sensory characteristics of goat cheese. Inter- species study by exchange of the fatty fraction and the skimmed fraction of cow's and goat's milk, Soft and semi-hard cheeses were manufactured with goat's and cow's milk, either with the original milk, or after exchange of the skimmed and the fatty fractions. The physico-chemical and sensory char- acteristics of the four types of cheeses obtained by both technologies were analyzed. Within the semi-hard cheeses group, more proteolytic activity was observed in goat's skimmed milk cheeses. In both soft and semi-hard cheeses, cow's milk produced more Iipolyzed cheeses. The goaty tlavour of semi-hard cheeses was strongly related to the presence of goat's fatty fraction, whereas in the soft cheeses, the goaty tlavour was intluenced by both milk fractions. The perception of this tlavour in the cheeses was related to the presence of C6:0, C8:0, C9:0, C 10:0, 4MeC8:0 and 4EtC8:0 fatty acids. Milky and buttery odours were related to cow's milk fat, whereas pungent, rancid, acid and bitter attributes differed between soft and semi-hard cheeses. The texture characteristics were only intlu- enced by the skimmed milk fraction in semi-hard cheeses, whereas they were also related to the fatty fraction in soft chee ses. © InralElsevier, Paris. goat's cheese / proteolysis / Iipolysis / volatile compound / flavour / texture

Differential scanning calorimetry of water buffalo and cow milk fat in mozzarella cheese

The thermal profiles of the fat in mozzarella cheeses made from cow milk (CM) and water buffalo milk (WBM) were obtained by differential scanning calorimetry (DSC). The DSC curves of mozzarella cheese made from WBM were distinguishable from those of CM. The curves resembled those of the corresponding milk fats and could be divided into low-, medium-, and high-temperature melting regions. The valley in the curve between the low- and medium-temperature melting regions was at 10.8°C in WBM cheese and below 10°C in CM cheese. In the WBM cheese, the area of the low-melting region was larger than the area of the medium-temperature melting region, but the two areas were equal in the CM cheeses. Mixtures of the two cheeses exhibited temperature and area values between those of the pure cheeses. Milk-fat mixtures showed similar behavior. The contrasting DSC melting profiles provide a way of distinguishing between the two mozzarella cheese types and for detecting mixtures of the two fats in mozzarella cheese.

Microbiological changes in a soft raw goat's milk cheese during ripening

The quantitative evolution of microflora and physicochemical characteristics of a French mold-ripened soft cheese made from raw goat's milk was studied throughout the ripening period. Similarities between the microbial changes in Camembert, a French soft cow's milk cheese and the goat's cheese were observed. Mesophilic Gram positives, mesophilic salt-tolerant bacteria, psychrotrophic salt-tolerant bacteria, and mesophilic Gram negatives were studied closely. Lactococci, Micrococci and Staphylococci showed proteolytic activities. Lactococcus was the dominant genus among the isolated Gram positives; Micrococcus and Staphylococcus were among the psychrotrophic and mesophilic salt-tolerant bacteria, respectively. Lipolytic activities were produced essentially by the salt-tolerant bacteria and the Gram negative microflora. At the end of the ripening process, the species Hafnia alvei dominated in the rind and core among the isolated Gram negative strains.

Main microbial flora present as natural starters in Cebreiro raw cow's-milk cheese (northwest Spain).

Thirty samples of Cebreiro, a fresh or short-time-ripened raw cow's-milk cheese produced in Northwest Spain, were analyzed for the presence of aerobic mesophilic bacteria, (AMC) lactic acid bacteria (LAB), enterococci and Micrococcaceae. Mean AMC and LAB counts exceeding 10(9)/g were higher than those reported for other fresh or short-time-ripened cheeses, although Micrococcaceae occurred in lower numbers (< 10(5)/g) than reported for other raw-milk cheeses. Out of a total of 126 LAB representation isolates, 59 were identified as enterococci (38 as Enterococcus faecalis) 30 as lactococci (24 as Lactococcus lactis subsp. lactis), 25 as leuconostocs (14 as Leuconostoc mesenteroides) and 6 were identified as mesophylic lactobacilli. The enterocci in general were more proteolytic and produced more diacetyl/acetoin than the other LAB groups lactic acid bacteria isolated. It seems that a starter for making Cebreiro cheese should contain these microorganisms so as to reproduce the typical characteristics of traditional raw milk Cebreiro cheeses.

Effects of variousMicrococcus strains on the ripening and organoleptic characteristics of Arz�a cow's-milk cheese

Ten batches of Arzua, a soft cow's-milk cheese produced in northwest Spain, were prepared from pasteurized milk. Two (control) batches (CB) were made with a commercial starter containingLactococcus lactis subspecieslactis andcremoris. Another eight batches (MB) were made with the commercial starter plus one of eightMicrococcus spp. strains previously isolated from raw-milk Arzua cheeses. In all MB, β-casein degradation over the 30-day ripening period was more pronounced (mean 31%) than in the CB (mean 12%). αS1-Casein degradation was highly variable in the MB, though mean degradation over the ripening period (75%) was similar to that observed in the CB (73%). Similarly, volatile fatty acid (VFA) content was highly variable in the MB, with the mean content at 30 days (3.8 mEq per 100 g) being higher than in the CB (1.6 mEq per 100 g). Rheological characterization of the cheeses (by uniaxial compression) revealed significant differences between batches, with some samples fracturing under the compression pressure applied and others not. Sensory evaluation also revealed significant differences. “Non-milk” aromas were more frequently detected in batches made with lipolytic micrococcal strains. Betweenbatch differences in tastes and texture were also detected. Multiple correlation analysis of the data obtained at day 15 of ripening revealed statistically significant positive correlations (r>0.70) between αS1-casein content and dry matter content, between αS1-casein content and sensorially evaluated firmness, and between VFA content and sensorially evaluated rancidity. Statistically significant negative correlations between sensorially evaluated firmness and the ratio of αS1-I content to αS1-casein content were detected. The results of this study suggest a need for further studies aimed at selecting those strains which could be most suitable for the production of Arzua cheeses; due to their effects on texture, αS1-caseinolytic strains seem to be more appropriate than β-caseinolytic ones.

Microbiological Study of León Raw Cow-Milk Cheese, a Spanish Craft Variety

The levels of several microbial groups (aerobic mesophilic flora, aerobic psychrotrophic flora, lactic acid bacteria, Micrococcaceae, enterococci, Enterobacteriaceae, and molds and yeasts), and some biochemical parameters were investigated during the manufacture and ripening of four batches of León cow cheese produced from raw milk without the addition of starter cultures. The study of the microbial characteristics of this cheese constitutes the first step towards the establishment of a starter culture which would allow the making of a product both more uniform and safer from the point of view of health. The total microbial counts were high throughout the elaboration and ripening. Almost all the microbial groups reached their maximum counts in curd and afterwards dropped throughout the ripening process. The greatest drop was shown by Enterobacteriaceae, which had disappeared after 3 months of ripening. Lactic acid bacteria were the major microbial group, reaching counts similar to the total aerobic mesophilic flora at all sampling points. Lactococcus lactis subsp. lactis dominated in milk (62.5% of the isolates obtained in de Man-Rogosa-Sharpe (MRS) agar at this sampling point), curd (82.5% of the isolates obtained at this sampling point) and one-week-old cheese (85% of isolates obtained at this sampling point), while Lactobacillus casei subsp. casei was the most predominant species in eight-week-old cheese (55% of isolates obtained at this sampling point) and twelve-week-old cheese (47.5% of isolates obtained at this sampling point). According to our data, a starter suitable for the production of León cow cheese would be made up of these two species. Some species of Leuconostoc or enterococci could also be added to this starter with the aim of improving the organoleptic characteristics of the final product or to emphasize the characteristics of this variety.

Biochemical characteristics of two types of unripe Spanish cow's milk cheese (Cebreiro and Pasiego varieties)

A detailed study of two varieties of unripe Spanish cheeses (Cebreiro and Pasiego) has been carried out for the first time. The overall chemical composition, the most relevant physicochemical parameters and the classical nitrogen fractions were determined in 24 batches of each variety. The chemical compositions of both varieties are fairly similar to those described in the literature for other unripe cheese varieties. Their low NaCl and ash contents are, above all, outstanding. The low pH of Cebreiro cheese (4.29 ± 0.20) is worth noting. The pH value of Pasiego cheese (5.59 ± 0.60) is similar to that found in other unripe cheeses obtained by enzymatic coagulation. Both varieties show very high Aw values which is to be expected in cheeses with a high moisture content, low NaCl content and very little protein degradation. The values determined for the different nitrogen fractions in both types of cheese indicate a very slight proteolysis. Linear discriminant analysis was applied to analytical data in order to differentiate both varieties. According to this statistical technique, d-lactic acid, NaCl, Ca, P, and ammonia nitrogen contents and pH and Aw values were the major discriminating variables involved in the differentiation. The correctly classified cases were 100%.

RHEOLOGICAL PROPERTIES OF GOAT MILK CHEESE: METHOD OF TRUE AXIAL STRESS VERSUS APPARENT AXIAL STRESS

Compressive moduli of elasticity and stress relaxation characteristics of soft goat milk cheese were compared with those of cow milk judged to be of comparable consistency. The true stress applied to a cheese sample was calculated from the variation of cross-sectional area of a cylindrical specimen during compression. Stress relaxation data were developed by measuring the force decay resulting from imposed compression of 5, 10, 20 and 40. The compressive elastic moduli for goat milk cheese were found to be lower than those for cow milk cheese. For cheese prepared from fresh goat milk, at least two distinct periods of stress relaxation were found for each compression level. Cheese prepared from reconstituted dehydrated goat milk showed one period of stress relaxation for each compression level.

Contributions of Cow, Sheep, and Goat Milks to Characterizing Branched-Chain Fatty Acid and Phenolic Flavors in Varietal Cheeses

Selected goat milk (fresh, semi-soft), sheep milk (Pyrenees, Roquefort), and cow milk (Blue, Cheddar) cheeses were analyzed for FFA using a sensitive gas chromatographic technique. Qualitative profiles for most FFA were similar in the samples, except that 4-ethyloctanoic acid was not found in cow milk cheese. Milk fat of cows contained low concentrations of 4-methyloctanoic acid, but milk fat of sheep and goat contained significant amounts of both 4-methyloctanoic and 4-ethyloctanoic acids, which contributed mutton-like and goat-like flavors, respectively. Pyrenees sheep milk cheese contained significant amounts of methyland ethyl-substituted phenols, which contributed characterizing sheep-like flavor notes to this cheese variety.

Contribution à l'étude de la flore levure de quelques grands types de fromages de chèvre

Summary - Study of the yeast flora composition of sorne wide varieties of goat cheese. A collection was made of 879 yeast strains isolated at different stages of cheese ripening in several types of cheese. Identification of these strains showed a rather wide diversity in the nature of flora. However, an important proportion of Kluyveromyces marxianus ssp, Debaryomyces hansenii, Saccharomyces cerevisiae species and their anascosporogenous forms was found. These species together represent between 20 and 80% of identified strains depending on the cheese groups concerned. For most selected cheese an important proportion of flora is represented by species rarely encountered in cow's milk cheese, Candida intermedia and Candida lipolytica, for instance, which are both found in highly significant proportions (about 20%) in 5 of the studied cheese types. Some specificity in goat cheese yeast flora was displayed and in particular when considering proportions of Candida strains including imperfect forms of sporogenous species. Candida as a whole was found in more than 60% of the identified population.

Detection of Adulteration in Cow, Goat, and Sheep Cheeses Utilizing Gas-Liquid Chromatographic Fatty Acid Data

The fatty acid profiles of 134 cheeses of foreign and domestic origin were examined by programmed temperature GLC of the fatty acid butyl esters. Goat milk and sheep milk cheeses exhibited a characteristically different lower chain length fatty acid pattern than did the cow milk cheeses. The mean lauric:capric fatty acid (12:10) ratio for cow cheeses was 1.16, this is the same mean value previous calculated for 140 butters. The mean ratio for 10 goat milk cheeses was .46. The mean ratio for sheep cheeses (Roquefort) was .58. The 12:10 ratio was used to determine the presence of cow's milk in cheeses labeled goat or sheep milk cheeses. The ratio becomes proportionally larger with increased substitution of cow's milk in lieu of goat's or sheep's milk in the manufacture of cheeses.