酸奶营养品质提升的加工工艺研究

牛奶中含有丰富的活性营养物质,包括乳铁蛋白、免疫球蛋白、乳过氧化物酶、α-乳白蛋白、β-乳球蛋白等。传统工艺生产的酸奶经过高温杀菌,活性营养物质几乎完全损失。为了避免这一情况,本文推出一种新的酸奶生产工艺,生产出的酸奶可保留大部分活性营养物质。首先将牛奶的乳脂进行分离,乳脂部分进行125 ℃、5 s杀菌,脱脂牛奶部分进行75 ℃、15 s杀菌,将两部分料液混合后加入菌种发酵至酸度75~85°T,破乳后冷却后熟8 h以上。经测定,新工艺酸奶中α-乳白蛋白、β-乳球蛋白、乳铁蛋白、免疫球蛋白、乳过氧化物酶含量分别为966 mg/L、1 963 mg/L、23.4 mg/L、102 mg/L、1 025 U/L,远高于传统工艺酸奶的68 mg/L、200 mg/L、0.7 mg/L、14 mg/L、0 U/L。通过对比新工艺与传统工艺酸奶保质期内的活菌数、黏度、酸度和口感,并无显著差异。

Study on the Processing Technology of Improving the Nutritional Quality of Yogurt

Milk is rich in active nutrients,including lactoferrin,immunoglobulin,lactoperoxidase,α- Lactalbumin,β- Lactoglobulin,and so on. After high temperature sterilization,the active nutrients of yogurt produced by traditional technology are almost completely lost. In this experiment,a new yogurt production process was used to produce high active nutritional yogurt. Firstly,the milk fat was separated,the milk fat part was pasteurized at 125 ℃ for 5 s,and the skim milk part was pasteurized at 75 ℃ for 15 s. After the mixture of the two parts,the Lactobacillus bulgaricus and Streptococcus lactis were added to ferment to the acidity of 75~85° T,and then cooled and postripenessd for more than 8 hours. After determination,the contents of α-lactalbumin,β-lactoglobulin,lactoferrin,immunoglobulin,and lactoperoxidase in the new craft yogurt are 966 mg/L,1 963mg/L,23.4 mg/L,102 mg/L,1 025 U/L,respectively,which were much higher than 68 mg/L,200 mg/L,0.7 mg/L,14 mg/L and 0 U/L of traditional yogurt. There was no significant difference in the number of viable bacteria,viscosity,acidity and taste between the new process and the traditional process yoghurts during their shelf life.