馒头发酵过程中酵母菌和乳酸菌的代谢作用

和制馒头面团时，添加20% 由酵母菌(Saccharomyces cerevisiae CGMCC 2.0562)和/ 或乳酸菌(Lactobacillus brevis CGMCC 1.0579)发酵的老面团进行混合发酵，通过检测pH 值、总酸度及可溶性糖含量的变化，研究老面团馒头发酵过程中微生物生长及代谢特性。采用高效液相色谱 (HPLC)- 蒸发光散射检测器(ELSD)检测可溶性糖(麦芽糖、蔗糖、果糖、葡萄糖)含量，其流动相为乙腈- 水体积比70:30，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：与对照组相比，添加老面团的样品pH 值较低，TTA 值较高，尤其是添加单一乳酸菌发酵老面团的样品酸度最低；不同样品发酵过程中各种可溶性糖的含量及变化趋势存在差异。由此看出，不同菌种对原料的利用不同，所以馒头面团发酵过程中代谢产酸及可溶性糖含量变化存在差异，这很可能会影响到馒头的品质。

Metabolism of Yeast and Lactic Acid Bacteria during Dough Fermentation of Mantou

When mixing dough of Mantou, 20% Laomiantuan fermented by Saccharomyces cerevisiae (CGMCC 2.0562) and/ or Lactobacillus brevis (CGMCC 1.0579) was added in dough. The pH, total acidity and soluble sugars were determined to explore the growth and metabolism characteristics of microorganisms during dough fermentation of Laomian Mantou. Soluble sugars including maltose, sucrose, fructose and glucose were determined using high performance liquid chromatography (HPLC) with evaporative light scattering detector (ELSD). The detection conditions were as follows: mobile phase, acetonitrile/water mixture (70:30, V/V); flow rate 1.0 mL/min; column temperature, 25 ℃; ELSD drift tube temperature, 83.5 ℃; and flow rate of carrier gas, 2.2 L/min. Compared with the control group, the samples with the addition of Laomian exhibited a lower pH and higher total acidity, especially the samples with addition of Laomian derived solely from Lactobacillus brevis (CGMCC 1.0579). The contents of soluble sugars and corresponding change trend differed in different samples with the addition of different Laomian starters during the fermentation. Therefore, acid-producing metabolism and soluble sugar content during the fermentation of dough may affect the quality of Mantou.