扣囊复膜酵母Y11固态发酵对麦麸理化特性的影响

Effects of solid-state fermentation with Saccharomycopsis fibuligera Y11 on physicochemical properties of wheat bran

[目的]本文旨在筛选固态发酵能提高麦麸抗氧化的酵母菌,并探究该菌固态发酵前、后麦麸理化特性的变化。[方法]使用酸面团中分离出的14株酵母菌分别对麦麸进行固态发酵,以总酚含量(TPC)和1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除率为指标,筛选具有最佳抗氧化效果的酵母菌并进行鉴定。采用扫描电镜观察发酵前、后麦麸的微观结构,并通过测定固态发酵前、后麦麸中可溶性蛋白、多肽、氨基酸、膳食纤维、烷基间二苯酚、黄酮及8种酚酸含量,探究固态发酵对麦麸理化特性的改善效果,并对麦麸总抗氧化性与麦麸活性物质含量(可溶性膳食纤维、多肽、水解氨基酸、总酚、黄酮、烷基间苯二酚及总游离酚酸)进行Spearman相关性分析。[结果]使用菌株Y11固态发酵后的麦麸,DPPH自由基清除率是未处理麦麸的2.53倍;TPC达2.84 mg·g^(-1),是未处理麦麸的1.70倍。经过内部转录间隔区(ITS)序列比对确定Y11菌株为扣囊复膜酵母菌(Saccharomycopsis fibuligera)。经扣囊复膜酵母Y11固态发酵后麦麸微观结构变得疏松粗糙,表面空隙增多。固态发酵后麦麸的可溶性膳食纤维含量显著增加,可溶性蛋白含量显著下降;多肽含量和17种游离氨基酸含量增加,总酚、黄酮、烷基间苯二酚及酚酸含量显著增加;8种游离酚酸中绿原酸含量增加最为显著,是未处理麦麸的3.70倍。此外,麦麸总酚、游离酚酸、可溶性膳食纤维及多肽含量与麦麸总抗氧化能力存在正相关性。[结论]扣囊复膜酵母Y11对麦麸进行固态发酵可显著改善麦麸的抗氧化能力及其理化特性。

[Objectives]This article aimed to screen the yeast which could improve the anti-oxidation of wheat bran by solid-state fermentation,and explore the differences in physicochemical properties of wheat bran before and after solid-state fermentation.[Methods]For solid-state fermentation of wheat bran,14 yeast strains isolated from sourdough were employed.The yeast with the best antioxidant effect was chosen and identified based on the total phenol content(TPC)and 1,1-diphenyl-2-picrylhydrazyl(DPPH)free radical scavenging rate.The microstructure of wheat bran was studied using scanning electron microscopy before and after solid-state fermentation.The improvement effect of solid-state fermentation on the physicochemical properties of wheat bran was investigated by measuring the contents of soluble protein,peptides,amino acids,dietary fiber,alkylresorcinols,flavonoids,and eight kinds of phenolic acids in wheat bran before and after solid-state fermentation.Moreover,Spearman correlation analysis was used to assess the correlation between the total antioxidant activity and the contents of active substances(soluble dietary fiber,peptides,hydrolyzed amino acids,total phenols,flavonoids,alkylresorcinols,and total free phenolic acids)in wheat bran.[Results]DPPH free radical scavenging rate was 2.53 times that of untreated wheat bran after solid-state fermentation by strain Y11,and the TPC reached 2.84 mg·g^(-1),which was 1.70 times that of untreated wheat bran.Y11 strain was classified according to its internal transcribed spacer(ITS)as Saccharomycopsis fibuligera.The microstructure of wheat bran became loose and rough,and the surface voids increased after S.fibuligera Y11 solid-state fermentation.The soluble dietary fiber content of wheat bran significantly increased and the soluble protein content significantly decreased after solid state fermentation.The content of peptides and 17 free amino acids increased,and the contents of total phenols,flavonoids,alkylresorcinols and phenolic acids significantly increased.Among the eight free phenolic acids,chlorogenic acid content significantly increased,which was 3.70 times higher than that of untreated wheat bran.Furthermore,the total antioxidant capacity of wheat bran was favorably correlated with the contents of total phenols,free phenolic acids,soluble dietary fiber,and polypeptides.[Conclusions]The solid-state fermentation by S.fibuligera Y11 can significantly improve antioxidant capacity and physicochemical properties of wheat bran.