内缓冲法提高乳清发酵剂活力的研究

在干酪乳清中添加一定量的ｐＨ６；０的柠檬酸钠──柠檬酸缓冲液可大大提高其缓冲能力。当在乳清中添加５％（０．５Ｍ，ｐＨ６．０）并以此为基质制备发酵剂时（发酵剂菌种组成为Ｓｔｒ．ＳａｌｉｖａｒｉｕｓＳｗｂｓｐ．ｔｈｅｒｍｏｐｈｉｌｕｓ和Ｌｂ．ｄｅｌｂｒｕｅｃｋｉｉＳｕｂｓｐ．ｂｕｌｇａｒｉｃｕｓ）可延缓乳酸菌发酵产酸所导致的ｐＨ下降过快而引起的抑制作用，与未添加者相比，制得的乳清发酵剂活力大为提高。当缓冲液添加量达１０％时，由于渗透压的增高抑制了乳酸菌的生长，对提高发酵剂活力没有作用。

Increase of whey Starter Culture Activity by Internal Buffering Methd

Addition of a pH 6.0,0.5M buffer consisted of sodium citrate and citrlc acidinto whey can increase its buffering capacity.When this whey medium was inoculatedwith mmixed lactic bacteria(Str.Salivarius Subsp.thermophilus and Lb.delbrueckiiSubsp.bulgaricus),it can buffer the lactic acid produced by lactic bacteria,ao as to delaythe lowing down of the whey medium PH which can inhibit the regeneration of the lacticbacteria,therefor,it can significantly raise the activity of whey starter culture,Inthisstudy a,5.0%buffer adding was found to be appropriate.When the amount was increased to 10.0%,it had no effect because of the increase of osmotic pressure of theMedium.