科研之友
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摘要
Buffalo milk contains (40-60 %) more protein, fat and calcium than cows%26apos; milk. These constituents were enhanced by ultrafiltration (UF) of cows%26apos; milk to give a product with similar levels to those found in the buffalo milk. Mozzarella-type curd was made from buffalo, cows%26apos; and UF cows%26apos; milk to compare the overall curd yield and quality. The curd yield on both dry and wet weight basis, curd moisture content and overall curd fat retention were found to be higher in the UF cows%26apos; milk than for either the buffalo or the cows%26apos; milk preparations. The minimum whey fat losses occurred in the UF cows%26apos; curd when compared to the cows%26apos; and the buffalo curd. The whey protein losses were found to be higher in the UF cows%26apos; curd than those for the buffalo and the cows%26apos; curds. The total mineral content of the curd was also higher in the UF cows%26apos; milk than that found in either the buffalo or the cows%26apos; milk. SEM micrographs showed that casein micelles sizes were different in the two different types of milk. Casein micelles were also observed to be deformed in the UF cows%26apos; milk samples. UF cows%26apos; milk contained higher amounts of both the alpha(s1)- and alpha(s2)-casein moieties than either the buffalo or the cows%26apos; milk. Buffalo milk was found to contain a higher concentration of beta-casein than either the UF cows%26apos; or untreated cows%26apos; milk samples. Gel strength was found to be higher in the resultant buffalo curd than for curds made from either native cows%26apos; milk or those made from UF cows%26apos; milk. The mineral distribution was also different in the three different types of bovine milk, measured by energy-dispersive X-ray (EDX) analysis. Differences in the curd quality observed between the buffalo and the cows%26apos; milk appear to result from the differences in casein composition and overall micelle structure, rather than casein concentration alone.
- 出版日期2013-7
