发芽糙米乳中双株复合乳酸菌的发酵特性研究
Study on characters of fermented germinated brown rice milk prepared with combination of two lactic acid bacteria
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摘要: 以发芽糙米为基质,将植物乳杆菌(Lactobacillus plantarum)、鼠李糖乳杆菌(L.rhamnosus)、嗜酸乳杆菌(L.acidophilus)、干酪乳杆菌(L.casei)4种乳酸菌经两两组合后,对发芽糙米乳进行发酵。通过对酸度、活菌数、脱水收缩作用敏感性、蛋白分解力、流变学性质等指标的测定来进行发酵特性评价,最终筛选出适合发酵发芽糙米乳的最佳菌株组合。实验结果表明:各组合在发芽糙米乳中的发酵特性不尽相同,其中嗜酸乳杆菌和干酪乳杆菌对各自组合贮藏过程中酸度的变化起主导作用,每组产品的活菌数均达8 lg cfu/m L以上,发酵特性的组间差异较为明显。综合考虑鼠李糖乳杆菌和干酪乳杆菌以1∶1的体积比组合所得产品品质较好,该发酵乳在4℃贮藏21 d后酸化程度较弱,p H下降了0.65个单位;乳清析出较少,7 d以后低于20%;活菌数变化小且冷藏期间数量一直高于8.5 lg cfu/m L,游离氨基酸增加0.08 mmol/L,流变学性质显示其黏稠度较高,相对易于储运。Abstract: Lactobacillus plantarum,L. rhamnosus,L. acidophilus and L. casei were used for germinated brown rice milk fermentation on pairwise combination. The best group was selected by evaluating their properties including acidity,viable count,susceptibility to syneresis,proteolytic activity and rheological property. Results showed that fermentation characteristics of these combinations in germinated brown rice milk were different,while L.acidophilus and L.casei dominated the acidity trend of each combination at 4 ℃ during a 21 d storage. Viable count of each groups were more than 8 lg cfu / m L,and the differences of processing properties were obvious between the two groups.The product fermented with L.rhamnosus and L.casei displayed weak post acidification which reduced 0.65 units p H and lower amount of whey was separated out.The viable count of the product was more than 8.5 lg cfu / m L and the free amino acid increased 0.08 mmol / L.Rheological measurement indicated that its viscosity was better.
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