茯苓菌液态发酵改良豆渣风味研究

Flavor improvement of okara by liquid fermentation with Wolfiporia cocos

豆渣是大豆加工过程产生的副产物,但具有强烈的豆腥味,导致其难以大规模应用。该文利用茯苓菌作为发酵菌株液态发酵豆渣,研究不同发酵时间(3、5、7、9 d)对发酵豆渣的风味轮廓和挥发性化合物成分的影响。结果表明,经茯苓菌发酵后,豆渣风味品质提升;顶空固相微萃取-气相色谱-质谱联用(headspace-solid phase microextraction-GC-MS,HS-SPME-GC-MS)检测发现,豆渣中主要不良风味物质为己醛,质量浓度为91.09μg/L;不良风味化合物含量整体随发酵时间的增加而减少,在培养时间为9 d时降幅最大,由77.33%降至14.88%;新具有了花香味、甜香味的风味特征且随发酵时间延长而不断增强,优美风味化合物含量随发酵时间增加而增长,在培养时间为9 d时增幅最大,由原始的6.16%增至69.83%。发酵豆渣中新生成的主要风味物质有芳樟醇、苯乙醇等,在发酵7 d时质量浓度最高,分别为136.51、10.56μg/L。综合来看,茯苓菌对豆渣豆腥味改良具有较好的效果,在培养时间为7 d时感官接受度最高,其能够为豆渣风味改良提供新的选择。

Okara is a by-product with strong beany flavor during soybean processing,and the off-flavor makes it difficult to be widely applied in food industry.In this study,the effects of different incubation durations(3,5,7 and 9 d)on the volatile compounds of okara fermented with Wolfiporia cocos were investigated.The results showed that the flavor of okara was improved after fermentation.By detecting with HS-SPME-GC-MS,the main off-flavor compound in okara was found to be hexanal and the content was 91.09μg/L.The content of off-flavor compounds decreased as the increasing of incubation duration,with the largest decrease at 9 d of fermentation from 77.33%to 14.88%.On the contrary,flower and sweet fragrance was newly generated,and enhanced with the increasing of incubation duration.The levels of pleasant flavor compounds increased with the increasing of incubation duration,and the largest increase was found at 9 d of fermentation from 6.16%to 69.83%.The newly generated flavor compounds were mainly linalool and phenethyl alcohol,which had the highest content of 136.51 and 10.56μg/L at 7 d of fermentation,respectively.In general,W.cocos could improve the flavor of okara,and the degree of sensory acceptance reached the highest at 7 d of fermentation.This study provides a new way for the flavor improvement of okara.