酵母菌和乳酸菌发酵老面团过程中对可溶性糖的代谢

Metabolism of soluble sugars in old dough fermented by yeast and lactic acid bacteria

采用Saccharomyces cerevisiae CGMCC2.0562和/或Lactobacillus brevis CGMCC1.0579纯菌接种发酵老面团,研究老面团发酵过程中微生物对可溶性糖的代谢作用。本实验确定了高效液相色谱(HPLC)-蒸发光散射检测器(ELSD)检测老面团中可溶性糖(麦芽糖、蔗糖、葡萄糖和果糖)的方法为流动相乙腈/水(70∶30,V/V),流速1.0mL/min,柱温25℃;ELSD漂移管温度83.5℃,载气空气流速2.2L/min。结果显示,S.cerevisiae2.0562能快速消耗麦芽糖、蔗糖和葡萄糖,对果糖的消耗较慢;接种单一L.brevis1.0579时,麦芽糖、葡萄糖的浓度增大,总体而言蔗糖浓度呈下降趋势,果糖呈上升趋势;接种S.cerevisiae2.0562和L.brevis1.0579时,麦芽糖、葡萄糖和果糖的浓度前几个小时降低,随后开始增加,而乳酸菌的存在减慢了酵母菌对蔗糖的消耗。由此看出接种不同菌种对可溶性糖的消耗不同,所以对老面团特性及代谢物的产生会有不同的影响,最终将影响馒头的品质。

The old dough were prepared using Saccharomyces cerevisiae（CGMCC 2. 0562）and/or Lactobacillus brevis（CGMCC 1. 0579）. The microbial metabolism of soluble sugars was studied during old dough fermentation. The method for detecting soluble sugars,which include maltose,sucrose,glucose,and fructose,was established by high efficiency liquid chromatography evaporative light scattering. The chromatographic condition：mobile phase was acetonitrile/water which was 70∶ 30（v/v）,flow rate was 1. 0mL/min,column temperature was 25℃. ELSD condition：The temperature of drift tube was 83. 5℃,flow rate of carrier gas was 2. 2L/min. The results showed that maltose,sucrose and glucose were fast consumed by S. cerevisiae 2. 0562,but the consumption of fructose was slower;when old dough fermented by single L. brevis 1. 0579,the concentration of maltose,glucose and fructose increase,in general the concentration of sucrose decreased;when old dough fermented by S. cerevisiae 2. 0562 and L. brevis 1. 0579,the concentration of maltose,glucose and fructose decreased in the initial hours,then increased,however the consumption of sucrose by yeast was slower with existence of L. brevis 1. 0579. Thus the consumption of soluble sugars was different when old dough were inoculated by different strains,so they would have different affection on the characteristic of old dough and production of metabolites. This will finally affect the quality of steamed bread.