Gerez C L, Rollán G C, de Valdez G F
Centro de Referencia para Lactobacilos (CERELA-CONICET), Tucumán, Argentina.
Lett Appl Microbiol. 2006 May;42(5):459-64. doi: 10.1111/j.1472-765X.2006.01889.x.
To evaluate the growth and metabolic activity of lactobacilli and pediococci strains in a gluten base medium (GBM), formulated for a proper selection of proteolytic strains to be used in sourdough fermentation.
Proteolytic activity by lactic acid bacteria (LAB) was evaluated by SDS-PAGE and by the amino acids released determined by reversed-phase high-performance liquid chromatography. Only 13 LAB (nine lactobacilli and four pediococci), among the 42 evaluated were able to utilize gluten as nitrogen source and to grow in GBM. Pediococcus pentosaceus CRL 797 showed a similar proteolytic activity to lactobacilli strains. In the majority of the cultures, basic amino acid group increased (c. 80% after 12 h incubation) mainly due to the release of ornithine, a flavour precursor of bread. Lysine, a limiting essential amino acid in wheat flour, increased by 150% in cultures of P. pentosaceus CRL 797.
This study allows selecting P. pentosaceus CRL 797 and L. plantarum CRL 759 as potential starter culture for type III sourdough fermentation. It is shown for the first time that pediococci strains isolated from sourdough are proteolytically active on gluten.
The physiological studies on gluten breakdown by LAB will contribute to the better selection of strains to produce breads with enhanced organoleptic characteristics.
评估乳酸菌和片球菌菌株在面筋基础培养基（GBM）中的生长和代谢活性，该培养基旨在筛选用于酸面团发酵的蛋白水解菌株。
通过SDS-PAGE评估乳酸菌（LAB）的蛋白水解活性，并通过反相高效液相色谱法测定释放的氨基酸。在所评估的42株菌中，只有13株LAB（9株乳酸菌和4株片球菌）能够利用面筋作为氮源并在GBM中生长。戊糖片球菌CRL 797表现出与乳酸菌菌株相似的蛋白水解活性。在大多数培养物中，碱性氨基酸组增加（孵育12小时后约增加80%），主要是由于鸟氨酸的释放，鸟氨酸是面包风味前体。赖氨酸是小麦粉中的一种限制性必需氨基酸，在戊糖片球菌CRL 797培养物中增加了150%。
本研究筛选出戊糖片球菌CRL 797和植物乳杆菌CRL 759作为III型酸面团发酵的潜在发酵剂。首次表明从酸面团中分离出的片球菌菌株对面筋具有蛋白水解活性。
LAB对面筋分解的生理学研究将有助于更好地选择菌株，以生产具有增强感官特性的面包。
