Physico-chemical, textural and microstructural properties during the cheese curds manufacturing with different commercial rennets

Abstract

In this study, it was aimed to determine the physico-chemical, textural and microstructural changes of the cheese curd produced using different commercial rennet. Methods and Results: After the milk was thermizated (60 °C for 15s), it was divided into 3 parts after pre-acidification up to a pH of about 6.02. Microbial fermented rennet (M), 100% calf rennet (C1) and recombinant fermented rennet (C2) were added to each portion of milk at 33 °C in proportions calculated according to the rennet strength and coagulation was achieved. Sampling was carried out for analysis from the gels before gel cutting and after milk gelation. After the pressing process was applied to milk gels to remove whey, the cheese curd was cut into molds of 6x6x6 cm 3 . The molds were dipped in hot (60 °C) whey and heat treated for 30 minutes. The internal temperature of the molds, which reached 55 °C with the heat treatment, were sampled for analysis after cooling to 22 °C. As a result, the highest dry matter was detected in C1 curd; however, total organic acid and total carboxylic acids were detected in the lowest amount. Propionic acid and hexanoic acid and hexanal were the highest in M and C2 curds; less voids were observed in the microstructure. Conclusions: While gels produced using different coagulants [microbial rennet (M), calf rennet (C1), and recombinant fermented rennet (C2)] showed similar textural qualities, they differed in the percentages of volatile compounds. Although cheese curds have similar color values; they differed significantly in terms of textural parameters, organic acids, volatile compounds, acidity and pH values, which play an important role in the acceptability of products by consumers. Therefore, it can be stated that the coagulant type plays an important role on curd quality. Significance and Impact of the Study: Texture and microstructure are highly related qualities. The structural organization of the constituents in the curd, independent of the total dry matter contents, can affect the texture. Recombinant fermented rennet can be preferred to other coagulants due to its protective effect and its contribution to taste, because it contains high lactic and propionic acids and the highest volatile carboxylic acid percentage, the highest yield, the lowest pH value and the highest hardness value.

Pastörize Koyun Sütü Kullanmanın Siirt Otlu Peynirinin Üretimi ve Olgunlaşması Üzerine Etkileri

“…The unique qualities of cheese are shaped by many factors. Milk constituents, microbiota composition, process parameters used, ripening regimes and many other factors are prevailed effective on the quality characteristics of the cheese (29)(30)(31)(32)(33)(34). Developing raw milk cheese technology is very difficult due to the risk of pathogenic bacteria (35).…”