Gänzle Michael G, Vermeulen Nicoline, Vogel Rudi F
Department of Agricultural, Food and Nutritional Science, University of Alberta, 4-10 Ag/For Centre, Edmonton, Alta., Canada T6G 2P5.
Food Microbiol. 2007 Apr;24(2):128-38. doi: 10.1016/j.fm.2006.07.006. Epub 2006 Sep 7.
The metabolic pathways of lactic acid bacteria that influence bread quality are coupled to the central carbon flux by the availability of cofactors influencing the cellular and environmental redox potential. Homo- and heterofermentative metabolism differ fundamentally with respect to the requirement for regeneration of reduced cofactors, NADH or NADPH. The utilization of co-substrates such as oxygen or fructose as electron acceptors by obligate heterofermentative lactobacilli is coupled to an increased production of acetate in dough. Recently, several oxidoreductases involved in cofactor regeneration were characterized and glutathione and short-chain aldehydes derived from lipid oxidation were identified as substrates for cofactor regeneration by Lactobacillus sanfranciscensis. Based on the different metabolic requirements for cofactor regeneration, homo- and heterofermentative lactobacilli exert divergent effects on redox-reactions in sourdough that influence bread quality beyond the formation of acetate. Proteolysis, followed by peptide or amino acid metabolism by LAB is one of the key routes of flavour formation in bread flavour, and enables the strain-specific formation of antifungal metabolites. Peptide metabolism as well as the metabolism of cysteine, arginine, and phenylalanine in Lactobacillus plantarum, L. sanfranciscensis, and Lactobacillus pontis is increasingly understood and these insights provide new opportunities for the directed application of sourdough LAB for improved bread quality.
影响面包品质的乳酸菌代谢途径通过影响细胞和环境氧化还原电位的辅因子可用性与中心碳通量相耦合。同型和异型发酵代谢在还原型辅因子NADH或NADPH的再生需求方面存在根本差异。专性异型发酵乳酸菌利用氧气或果糖等共底物作为电子受体与面团中乙酸产量的增加相关联。最近，对几种参与辅因子再生的氧化还原酶进行了表征，并确定谷胱甘肽和脂质氧化产生的短链醛是旧金山乳杆菌辅因子再生的底物。基于辅因子再生的不同代谢需求，同型和异型发酵乳酸菌对酸面团中的氧化还原反应产生不同影响，这些影响超出乙酸形成，对面包品质产生影响。蛋白水解作用，随后由乳酸菌进行肽或氨基酸代谢，是面包风味形成的关键途径之一，并能实现菌株特异性抗真菌代谢物的形成。植物乳杆菌、旧金山乳杆菌和Pontis乳杆菌中的肽代谢以及半胱氨酸、精氨酸和苯丙氨酸的代谢越来越为人所知，这些见解为有针对性地应用酸面团乳酸菌以改善面包品质提供了新机会。
