Effect of rate of addition of starter culture on textural characteristics of buffalo milk Feta type cheese during ripening

Possibility of Using Different Calcium Compounds for the Manufacture of Fresh Acid Rennet Cheese from Goat's Milk

Calcium can be added to cheese milk to influence the coagulation process and to increase cheese yield. Calcium compounds used in the dairy industry show substantial differences in their practical application. Therefore, this study aimed to evaluate the potential use of 0, 5, 10, 15, and 20 mg Ca 100 g-1 of milk in the form of calcium gluconate, lactate, and carbonate as alternatives to calcium chloride in manufacturing fresh acid rennet cheese from high-pasteurized (90 °C, 15 s) goat's milk. The pH value of the cheese was reduced most strongly by the addition of increasing doses of calcium lactate (r = -0.9521). Each cheese sample showed increased fat content with the addition of calcium. Only calcium chloride did not reduce protein retention from goat's milk to cheese. The addition of 20 mg Ca 100 g-1 of milk in the form of gluconate increased cheese yield by 4.04%, and lactate reduced cheese yield by 2.3%. Adding each calcium compound to goat's milk significantly increased Ca and P levels in the cheese (p ≤ 0.05). The highest Ca levels were found in cheese with the addition of 20 mg Ca 100 g-1 of milk in the form of lactate. In all groups, similar contents of Mn, Mo, and Se were found. Calcium addition significantly affected cheese hardness, while higher calcium concentrations increased hardness. Carbonate caused the greatest increase in the cohesiveness of cheese. The addition of calcium compounds increased the adhesiveness and springiness of cheese compared to controls. The cheese with calcium chloride had the highest overall acceptability compared to the other cheese samples. The addition of calcium carbonate resulted in a lower score for appearance and consistency, and influenced a slightly perceptible graininess, sandiness, and stickiness in its consistency, as well as provided a slightly perceptible chalky taste.

Compositional and textural properties of goat’s milk cheese prepared using dahi (yogurt) as the starter culture

Abstract This study aimed to develop goat’s milk cheese to conserve the major milk constituents. Household dahi (yoghurt) is an inexpensive source of starter cultures that contains several types of microorganism of which most are thermophilic in nature and can be used in the production of goat’s milk cheese. Different concentrations of dahi (0.5%, 1.0%, 1.5%, 2.0% and 2.5%) were used to prepare the cheeses following the standard procedure for cheese manufacturing. The cheeses were analysed for their physicochemical, textural and organoleptic parameters. The highest yield was recorded for T1.0% (17.33%) and the lowest for T2.5% (15.58%). Significant (p < 0.05) differences were found for the pH, acidity and moisture content of the different goat’s milk cheese samples. The moisture content was highest in T0.5% (59.30) and lowest in T2.5% (52.20). The texture profile was significant (p < 0.05) for firmness, adhesiveness, gumminess and chewiness between the treatments. The sensory scores indicated that T1.0% was preferred by the panellists, followed by T1.5% and then the other treatments. It was concluded that goat’s milk cheese could be prepared with good quality characteristics using 1% dahi as the starter culture.

Performance evaluation of bulk freeze dried starter cultures of dahi and yoghurt along with probiotic strains in standardized milk of cow and buffalo

Performance of bulk freeze dried (BFD) cultures of dahi (D) and yoghurt (Y) either with or without probiotic cultures (AB -Lactobacillus acidophilus and Bifidobacterium bifidum) in standardized milk of cow and buffalo was evaluated. In buffalo milk, significantly (p < 0.05) low viable count of probiotic culture combination of dahi cultures (DAB) over non probiotic combination (D) was noticed; whereas, difference in counts of yoghurt culture combinations Y and YAB was not significant. The culture activity of D and DAB was similar in both types of milk, however, the volatile acidity (VA) produced by combination D was higher (32.5 ml/50 g sample) in buffalo milk than in cow milk (29.2 ml/50 g sample). Whereas, DAB produced very low amount of VA (16 ml/50 g sample) both in cow and buffalo milk. The diacetyl and tyrosine contents produced by either D or DAB in cow or buffalo milk were in the same order. Although Y and YAB produced slightly more VA in buffalo milk than in cow milk, significant change in the performance of yoghurt cultures (Y or YAB) both in cow and buffalo milk was not noticed. However, the VA and acetaldehyde produced by YAB either in cow and buffalo milk was higher than that by combination Y. Addition of probiotic cultures significantly enhanced the production of acetaldehyde content in both types of milk. Difference in tyrosine content in yoghurt made either with cow or buffalo milk was not significant. Overall, the present study indicated that the BFD cultures can be used to prepare dahi or yoghurt either from cow or buffalo milk, without affecting the biochemical profile of these products.

Yoghurt with candied chestnut: freeze drying, physical, and rheological behaviour

As a novel product, yoghurt powder was produced by freeze drying and with added candied chestnut puree at ratios of 5, 10, and 20 % by weight. During the freeze drying process, mass loss, water activity, and the moisture content of the samples were determined and the colour (Hunter L, a, b) of the yoghurt powder products was measured. Results showed that increasing the percentage of candied chestnut puree resulted in an increase in water activity, moisture content, and colour change values of the end product. The drying behaviour, drying rate versus free moisture content, was also investigated. It was observed that yoghurt with or without added candied chestnut puree could be satisfactorily freeze-dried. Moreover, the performance of the dried product was observed in a ready-to-use, reconstituted form. For this purpose, the obtained powders were reconstituted to their original moisture contents. Shear stress and apparent viscosity against shear rate in a range of 1-1,000 (1/sec) was then measured by a Haake-Mars rotary viscometer. According to the results, the apparent viscosities of reconstituted products, as plain yoghurt and the one with an added 5 % chestnut puree were lower than that of fresh yoghurt. However, reconstituted yoghurts containing 10 % and 20 % chestnut puree had apparent viscosities higher than fresh yoghurt. Power Law explained well the rheological behaviour of reconstituted yoghurt samples for the applied shear rate range. Based on rheological data and sensory analysis, it was concluded that the freeze dried yoghurt containing 10 % (w/w) candied chestnut puree was an acceptable novel product.