Faculty of Agriculture Development, Laboratory of Microbiology, Biotechnology and Hygiene, Democritus Univ. of Thrace, 193 Pantazidou St., GR-68200 Orestiada, Greece.
J Food Sci. 2012 Dec;77(12):C1256-62. doi: 10.1111/j.1750-3841.2012.02985.x. Epub 2012 Nov 21.
The natural mixed culture kefir was immobilized on boiled corn grains to produce an efficient biocatalyst for lactic acid fermentation with direct applications in food production, such as sourdough bread making. The immobilized biocatalyst was initially evaluated for its efficiency for lactic acid production by fermentation of cheese whey at various temperatures. The immobilized cells increased the fermentation rate and enhanced lactic acid production compared to free kefir cells. Maximum lactic acid yield (68.8 g/100 g) and lactic acid productivity (12.6 g/L per day) were obtained during fermentation by immobilized cells at 37 °C. The immobilized biocatalyst was then assessed as culture for sourdough bread making. The produced sourdough breads had satisfactory specific loaf volumes and good sensory characteristics. Specifically, bread made by addition of 60% w/w sourdough containing kefir immobilized on corn was more resistant regarding mould spoilage (appearance during the 11(th) day), probably due to higher lactic acid produced (2.86 g/Kg of bread) compared to the control samples. The sourdough breads made with the immobilized biocatalyst had aroma profiles similar to that of the control samples as shown by headspace SPME GC-MS analysis.
天然混合发酵乳杆菌被固定在煮沸的玉米粒上，制成了一种高效的生物催化剂，可直接应用于食品生产，如酸面团面包制作。该固定化生物催化剂最初在不同温度下通过奶酪乳清发酵来评估其生产乳酸的效率。与游离发酵乳杆菌相比，固定化细胞提高了发酵速度，增强了乳酸的生成。在 37°C 下通过固定化细胞发酵可获得最大乳酸产量（68.8 g/100 g）和乳酸生产速率（12.6 g/L/天）。然后，该固定化生物催化剂被评估为酸面团面包制作的发酵剂。所生产的酸面团面包具有令人满意的特定面包体积和良好的感官特性。具体而言，通过添加 60%w/w 的含有固定化在玉米上的发酵乳杆菌的酸面团制作的面包，在第 11 天的外观方面对霉菌污染的抗性更强，这可能是由于与对照样品相比，产生了更高的乳酸（2.86 g/Kg 的面包）。通过顶空 SPME GC-MS 分析表明，用固定化生物催化剂制作的酸面团面包的香气特征与对照样品相似。
