【摘要】 将合格的新鲜牛乳置于常温下(20~25℃),让其发酵酸败,然后加碱调酸、再酸败、再加碱调酸,分别测定各阶段乳样煮沸前后的酸度和碱性物质。结果表明,合格的新鲜乳和首次酸败乳煮沸前后酸度变化不大,酸败调碱乳和调碱酸败乳煮沸前后酸度发生了很大的变化;煮沸前后碱性物质检测结果也不一致。因此,牛乳新鲜度的判定要通过牛乳煮沸前后的酸度、酸度值差以及煮沸后碱性物质检测等指标来综合判定。更多还原

【Abstract】 Put the qualified fresh milk at the room temperature(20~25℃) and it will be naturally fermented and rancid and adding alkali for acidity regulating.It will naturally fermented and rancid again then using alkali for acidity regulating again. Acidity and alkaline substance detection, for not boiling milk samples and boiled milk samples, is carried out at different stages in this experiment.Result shows there is little change between qualified fresh milk and the not boiling or boiled milk sample which is first time being rancid.But the rancid milk with alkali regulating and the later alkali regulating rancid milk shows a significant acidity change before and after bolied.Mean while the alkaline substance is also different.In conclusion, the freshness of cow milk should be evaluated comprehensively by the acidity, acidity before and after bolied, acidity difference between before and after bolied, detected alkaline substance,etc.更多还原