以来源于葡萄天然发酵液的酿酒酵母(Saccharomyces cerevisiae)、乳酸明串珠菌(Leuconostoc lactis)和植物乳杆菌(Lactobacillus plantarum)制备一种优良的新型天然复合发酵剂以提高面包的烘焙品质。发酵剂中3株菌的最适配比为1∶1.5∶1.5,此时面包比容和硬度均优于普通酵母面包;采用质构仪(texture anylyzer,TA)、差示量热扫描仪(differential scanning calorimetry,DSC)以及固相微萃取-气相色谱-质谱联用(solid phase micro-extraction-gas chromatographic-mass spectrometry,SPME-GC-MS)技术,考察天然复合发酵剂面包的老化性能及风味。结果表明,天然复合发酵剂发酵能显著降低储藏期内面包芯硬度和老化焓,延缓面包老化,面包中挥发性风味物质的种类增加11种,相对含量提高4.81%;天然复合发酵剂在4 ℃储藏90 d后菌株存活率仍有81.78%。此发酵剂具有活菌数高、发酵能力强、货架期长且能显著改善面包品质和风味的优点。
Saccharomyces cerevisiae, Leuconostoc lactis and Lactobacillus plantarum, which were screened from grape natural fermentation broth, were used to prepare an excellent natural mixed starter to improve the baking quality of bread. The optimal ratio of three strains in the starter was 1∶1.5∶1.5, meanwhile, the specific volume and hardness of the bread were better than those of the common yeast bread. The texture analyzer (TA), differential scanning calorimetry (DSC) and solid phase micro-extraction-gas chromatographic-mass spectrometry (SPME-GC-MS) were used to determine the aging properties and flavor of bread fermented by natural mixed starter, and the results showed that the natural mixed starter could reduce the hardness and aging enthalpy of bread during storage and delay the staling of the bread, thus the number and the relative content of volatile flavor compounds in bread increased by 11 species and 4.81%, respectively. The survival rate of natural mixed starter was 81.78% after 90 days of storage at 4 ℃. The starter with the advantages of high viability and fermentation ability could be applied in bakery industry to improve quality, flavor and shelf life of bread.