单一菌与复合菌发酵甘草渣产有机酸能力比较

Comparison of organic acid production capacity of licorice residues fermented by single and complex bacteria

为研究单一菌与复合益生菌对甘草渣发酵饲料品质的影响,试验以甘草渣为基础原料,与麸皮、豆粕、糖蜜复配,在此基础上以单菌(植物乳杆菌、酿酒酵母)和复合菌(植物乳杆菌、酿酒酵母、枯草芽孢杆菌)为发酵剂,借助食品检测中的碱滴定法,测定发酵饲料中的总酸含量,通过比较发酵饲料总酸含量及pH结合感官评价,衡量发酵饲料的品质。结果表明:(1)单菌在不同碳氮比条件下发酵,碳氮比为30时生成有机酸含量较碳氮比为25提高了2.8倍。(2)单菌发酵第7天时有机酸含量达到最高值,且pH在发酵第7天时达到最低值。(3)复合益生菌发酵组(E组、F组)与单菌酿酒酵母组(B组)比较甘草渣发酵饲料中有机酸生成量分别提高了52%、52.48%。由此可见,复合益生菌(植物乳杆菌、酿酒酵母、枯草芽孢杆菌)有利于促进甘草渣饲料发酵,无论是气味还是有机酸生成量均比单一菌株甘草渣发酵更优,甘草渣有成为发酵饲料的潜在价值。

The aim of this experiment was to evaluate the effects of single and compound probiotics on the quality of licorice residue fermented feed.The experiment used licorice residue as the basic raw material,compounded with bran,soybean meal and molasses,on the basis of which single bacteria(Lactobacillus plantarum,Saccharomyces cerevisiae)and compound bacteria(Lactobacillus plantarum,Saccharomyces cerevisiae,Bacillus subtilis)were used as the fermentation agents,and the total acid content of fermented feed was determined with the help of the alkali titration method in the food testing,and the quality of fermented feed was measured by comparing the total acid content of the fermented feed with pH combined with the organoleptic evaluation.The results showed that:(1)Single bacteria fermented under different carbon and nitrogen ratios,and the content of organic acid generated at a carbon and nitrogen ratio of 30 increased 2.8 times compared with that at a carbon and nitrogen ratio of 25.(2)The content of organic acid reached the highest value at the 7th day of fermentation of the single bacteria,and the pH reached the lowest value at the 7th day of fermentation.3)Organic acid production in licorice pomace fermented feed was increased by 52%and 52.48%in the complex probiotic fermentation groups(groups E and F)compared with monobacterial brewer's yeast group(group B).It could be seen that the composite probiotics(Lactobacillus plantarum,Saccharomyces cerevisiae,Bacillus subtilis)were conducive to the promotion of licorice residue feed fermentation,both the odor and the amount of organic acid production was better than a single strain of licorice residue fermentation,licorice residue had the potential value of becoming a fermented feed.