Edema Mojisola O, Sanni Abiodun I
Department of Microbiology, College of Natural Sciences, University of Agriculture, P.M.B. 2240, Abeokuta, Nigeria.
Food Microbiol. 2008 Jun;25(4):616-25. doi: 10.1016/j.fm.2007.12.006. Epub 2008 Jan 29.
This paper focuses on the functional properties of maize sour-dough microflora selected and tested for their use as starter cultures for sour maize bread. Lactic acid bacteria and yeasts isolated from spontaneously fermented maize dough were selected based on dominance during fermentation and presence at the end of fermentation. Functional properties examined included acidification, leavening and production of some antimicrobial compounds in the fermenting matrix. The organisms previously identified as Lactobacillus plantarum, Lb. brevis, Lb. fermentum, Lb. acidophilus, Pediococcus acidilactici, Leuconostoc mesenteroides and Leuconostoc dextranicum and Saccharomyces cerevisiae were used singly and as mixed cultures in the fermentation (fermentation time: 12h at 28+/-2 degrees C) of maize meal (particle size >0.2mm). The pH fell from an initial value of 5.62-3.05 in maize meals fermented with Lb. plantarum; 4.37 in L. dextranicum+S. cerevisiae compared with the value for the control (no starter) of 4.54. Significant differences (P <or =0.05) were observed in values obtained for the functional properties tested when starters were inoculated compared with the control (no starter) except for leavening. Bivariate correlations at 0.01 levels (two-tailed) showed that significant correlations existed among pH and production of antimicrobial compounds in the fermenting meals, the highest correlation being between production of diacetyl and acid (0.694), a positive correlation indicating that production of both antimicrobial compounds increase together with time. Antimicrobial activities of the fermented maize dough were confirmed by their abilities to inhibit the growth of Salmonella typhi, Escherichia coli, Staphylococcus aureus and Aspergillus flavus from an initial inoculum concentration of 7 log cfu ml(-1)) for test bacteria and zone of inhibition of up to 1.33 cm for aflatoxigenic A. flavus. The findings of this study form a database for further studies on the development of starter cultures for sour maize bread production as an alternative bread specialty.
本文聚焦于为酸玉米面包筛选并测试用作发酵剂的玉米酸面团微生物区系的功能特性。从自发发酵的玉米面团中分离出的乳酸菌和酵母，是根据其在发酵过程中的优势地位以及发酵结束时的存在情况来挑选的。所检测的功能特性包括发酵基质中的酸化、膨松以及一些抗菌化合物的产生。先前鉴定为植物乳杆菌、短乳杆菌、发酵乳杆菌、嗜酸乳杆菌、嗜酸片球菌、肠系膜明串珠菌、右旋糖酐明串珠菌和酿酒酵母的微生物，被单独以及混合用于玉米粉（粒度>0.2毫米）的发酵（发酵时间：28±2℃下12小时）。在用植物乳杆菌发酵的玉米粉中，pH值从初始值5.62降至3.05；在右旋糖酐明串珠菌+酿酒酵母发酵的玉米粉中，pH值为4.37，而对照（无发酵剂）的pH值为4.54。与对照（无发酵剂）相比，接种发酵剂时所测试的功能特性值存在显著差异（P≤0.05），但膨松特性除外。在0.01水平（双侧）的双变量相关性表明，发酵玉米粉中的pH值与抗菌化合物的产生之间存在显著相关性，最高相关性存在于双乙酰和酸的产生之间（0.694），正相关表明这两种抗菌化合物的产生都随时间增加。发酵玉米面团的抗菌活性通过其抑制伤寒沙门氏菌、大肠杆菌、金黄色葡萄球菌和黄曲霉生长的能力得到证实，对于测试细菌，初始接种浓度为7 log cfu ml(-1)，对于产黄曲霉毒素的黄曲霉，抑菌圈直径可达1.33厘米。本研究结果为进一步研究用于生产酸玉米面包这一替代面包品种的发酵剂奠定了数据库基础。
