多菌种固态发酵法提高燕麦全谷物的蛋白质营养品质

研究植物乳杆菌70810与米根霉在燕麦全谷物基质中共固态发酵特性及对燕麦营养价值的影响，利用平板计数法和高效液相色谱法分别测定乳酸菌的生长情况和真菌麦角固醇含量，利用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、考马斯亮蓝法和邻苯二甲醛法测定发酵过程中燕麦蛋白质的水解情况。结果表明：燕麦全谷物基质中，随着植物乳杆菌70810和米根霉共同发酵时间的延长，乳酸菌活菌数和麦角固醇含量逐渐增加，72?h分别达到（8.46±0.04）（lg（CFU/g））和（137.04±6.13）μg/g，其中活菌计数结果比植物乳杆菌70810单独发酵时提高了7.14%；pH值由5.34±0.12降低至3.74±0.04，总酸质量分数由（0.23±0.02）%增加至（1.08±0.08）%；蛋白质发生明显水解，发酵至72?h，可溶性蛋白（以牛血清白蛋白当量计）含量为（11.58±0.16）mg/g，分子质量小于10?kDa肽（以胰酪蛋白胨当量计）含量为（366.51±1.30）mg/g。发酵后的燕麦蛋白具有更高的营养价值，氨基酸组成更为合理，赖氨酸含量显著增加，必需氨基酸指数提高至75.63±0.10，蛋白质生物价提高至70.74±0.13。

Improved Protein Nutritional Quality of Whole Oat Grains by Solid State Fermentation with Mixed Strains

In this paper, the solid state fermentation of whole oat grains was carried out by simultaneous inoculation with Lactobacillus plantarum 70810 (L. plantarum 70810) and Rhizopus oryzae (R. oryzae). Our aim was to evaluate fermentation characteristics and the effect of mixed fermentation on the protein nutritional quality of oat. Bacterial growth and ergosterol content were investigated by plate count method and high-performance liquid chromatography (HPLC), respectively. Proteolysis during the fermentation process was measured using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), the Bradford assay and the o-phthaldialdehyde (OPA) method. Results showed that the number of viable bacterial cells and ergosterol content gradually increased during mixed culture fermentation, reaching (8.46 ± 0.04) (lg(CFU/g)), 7.14% higher than that of pure culture fermentation with L. plantarum 70810, and (137.04 ± 6.13) μg/g at 72 h, respectively. pH value decreased from 5.34 ± 0.12 to 3.74 ± 0.04, and total acidity increased from (0.23 ± 0.02)% to (1.08 ± 0.08)%. As significant proteolysis occurred at 72 h , the soluble protein content (calculated as bovine serum albumin equivalent) was raised to (11.58 ± 0.16) mg/g, and the content of peptides (calculated as casein tryptone equivalent) with molecular mass lower than 10 kDa reached its highest value of (366.51 ± 1.30) mg/g. Fermented oat had higher protein nutritional value and improved amino acid composition with a significant increase in lysine content. In addition, the essential amino acid index (EAAI) increased to 75.63 ± 0.10, and the protein biological value (BV) to 70.74 ± 0.13 after mixed culture fermentation as compared to pure culture fermentation.