HPMC的持水性能及其对面包酵母抗冻性的影响

Water-Holding Capacity of HPMC and Its Antifreeze Effect on Baker's Yeast Cells

摘要:

为研究羟丙甲纤维素醚（HPMC）的持水性能及其对提高酵母细胞抗冻性的作用，采用差示扫描量热法测定多种型号HPMC和其他抗冻剂抗冻活性AF（-）；再将HPMC添加到面团中，测定冻藏45 d后面团中可冻结水比例的变化；最后对比在冻藏过程中不同抗冻剂对酵母细胞存活率（η，%）的影响。结果表明HPMC的AF随取代聚合度的增大而增大，可高达9.82，较海藻糖、谷氨酸AF分别为5.99和3.98有明显优势；冻藏45 d后，添加质量分数1% HPMC面团的可冻结水质量分数由空白面团的65.2%降至51.3%；酵母菌液冻藏0~6 d内，η下降迅速，8 d后稳定，添加质量分数1%的HPMC的样品的η相比于空白样由23.2%提高至55.5%，且在0~1.0%范围内，η随抗冻剂质量分数增大而显著增大。

Abstract:

In order to study water holding capacity of HPMCand its antifreeze effectonbaker's yeast cells，the method of DSC was used to measure the antifreeze active of HPMC and other cryoprotectants. HPMC was used into frozen dough to detect the frozen watercontent after 45 d. Finally，the yeast cellsviability（η） in samples with different cryoprotectants was investigated in different frozen days and concentration. The experimental results showed that the AF of HPMC changes with its degree of substitution and polymerization，up to 9.82，has a significant advantage than Glutamate and Trehalose，which were 5.99 and 3.98. After being frozen for 45d，the frozen water in the dough with 1% HPMC decreased to 51.3% compared with the 65.2% of control samples. The yeast cellsviability（η） decreased quickly in the first 6d，and was stable after 8d，but the η was increased from 23.2% to 55.5% by adding 1% of HPMC，and η was increasing by theincreasing concentration of HPMC from 0 to 1%.