小麦制酒精残渣发酵菌种筛选及其产物小肽的抗氧化活性

Screening of the strains and antioxidant activity of small peptide from solid-state fermentation of the residue from wheat alcohol processing

研究了小麦制酒精残渣固态好氧发酵菌种的筛选以及发酵过程中产生的小肽的抗氧化活性。选用地衣芽孢杆菌D-1和枯草芽孢杆菌KG109与公司现行的酒曲进行比较,试验了接种量、含水量不同水平,以物料水分高和产小肽多为最优组合,并测定其小肽清除1,1-二苯基-2-三硝基苯肼(DPPH)自由基和羟自由基(·OH)活性及总还原力。结果表明,D-1性能最优,接种量3%,含水量70%时,发酵产物中酸溶蛋白和粗蛋白均极显著高于酒曲对照组(P<0.01),其酸溶蛋白含八肽、七肽、五肽、四肽和三肽共5种小肽,除八肽外,其他4种小肽均具有一定的·OH和DPPH清除能力,且5 mg/mL的四肽与0.5 mg/mL谷胱甘肽的总还原力相当。结论:D-1是提高小麦制酒精残渣饲用品质的高效发酵菌种,其固态发酵过程中产生的小肽大部分具有较强抗氧化活性。

Screening of the strains for solid-state aerobic fermentation of the residue from wheat alcohol progress- ing and the antioxidant activity of small peptide from the fermentation were studied. Using Bacillus licheniformis D-1 and Bacillus subtilis KG109 as strains to ferment and compare with koji used by the company at present, the amount of inoculum and levels of moisture content were tested. The result with higher moisture and more small peptides was opti- mum combination. Then DPPH scavenging activity, hydroxyl radical scavenging activity and the total reducing capaci- ty of its small peptides were measured. The results showed that D-1 was the best when inoculums was 3% and mois- ture content was 70% , and the content of acid soluble proteins and crude proteins in the product were both signifi- cantly higher than those in the control （ P 〈 0.01 ）. Five peptides with 8, 7, 5,4 and 3 amino acids respectively were separated from the acid soluble proteins. The other four peptides all had DPPH radical scavenging activity and hydrox- yl radical scavenging activity except peptide with 8 amino acid residues, and the total reducing capacity of 5 mg/mL of peptide with 4 acid residues was equivalent to 0.5 mg/mL glutathione. These results implied that D-1 was an efficient strain to improve the forage quality of the residue from wheat alcohol progressing and most of small peptides had strong antioxidant activity.