Centro de Referencia para Lactobacilos (CERELA)-CONICET, Chacabuco 145, 4000 San Miguel de Tucumán, Argentina.
J Dairy Res. 2012 May;79(2):201-8. doi: 10.1017/S0022029912000040.
The high nutritional value of whey makes it an interesting substrate for the development of fermented foods. The aim of this work was to evaluate the growth and proteolytic activity of sixty-four strains of lactic acid bacteria in whey to further formulate a starter culture for the development of fermented whey-based beverages. Fermentations were performed at 37 °C for 24 h in 10 and 16% (w/v) reconstituted whey powder. Cultivable populations, pH, and proteolytic activity (o-phthaldialdehyde test) were determined at 6 and 24 h incubation. Hydrolysis of whey proteins was analysed by Tricine SDS-PAGE. A principal component analysis (PCA) was applied to evaluate the behaviour of strains. Forty-six percent of the strains grew between 1 and 2 Δlog CFU/ml while 19% grew less than 0·9 Δlog CFU/ml in both reconstituted whey solutions. Regarding the proteolytic activity, most of the lactobacilli released amino acids and small peptides during the first 6 h incubation while streptococci consumed the amino acids initially present in whey to sustain growth. Whey proteins were degraded by the studied strains although to different extents. Special attention was paid to the main allergenic whey protein, β-lactoglobulin, which was degraded the most by Lactobacillus acidophilus CRL 636 and Lb. delbrueckii subsp. bulgaricus CRL 656. The strain variability observed and the PCA applied in this study allowed selecting appropriate strains able to improve the nutritional characteristics (through amino group release and protein degradation) and storage (decrease in pH) of whey.
乳清的高营养价值使其成为开发发酵食品的有趣基质。本工作的目的是评估 64 株乳酸菌在乳清中的生长和蛋白水解活性，以进一步制定发酵乳清基饮料的起始培养物。在 37°C 下，在 10%和 16%（w/v）复水乳清粉中进行发酵 24 小时。在 6 和 24 小时孵育时测定可培养菌数、pH 值和蛋白水解活性（邻苯二甲醛试验）。通过 Tricine SDS-PAGE 分析乳清蛋白水解。应用主成分分析（PCA）评估菌株的行为。46%的菌株在两种复水乳清溶液中生长 1 至 2 Δlog CFU/ml，而 19%的菌株生长少于 0.9 Δlog CFU/ml。关于蛋白水解活性，大多数乳酸菌在最初的 6 小时孵育期间释放氨基酸和小肽，而链球菌消耗乳清中最初存在的氨基酸以维持生长。研究菌株降解了乳清蛋白，尽管程度不同。特别关注主要的乳清过敏原β-乳球蛋白，它被嗜酸乳杆菌 CRL 636 和保加利亚乳杆菌亚种 CRL 656 降解最多。本研究中观察到的菌株变异性和应用的 PCA 允许选择适当的菌株，这些菌株能够改善乳清的营养特性（通过氨基基团释放和蛋白降解）和储存特性（降低 pH 值）。
