不同处理对发酵红枣汁键合态香气化合物释放的影响

Effects of different treatments on the release of bonded aroma compounds from fermented jujube juice

摘要:

乳酸菌发酵改变了红枣汁的香气组成,这可能与键合态香气化合物(GBVs)的释放有关。采用Amberlite XAD-2树脂吸附洗脱分离得到发酵红枣汁GBVs,研究在β-D-葡萄糖苷酶酶解(38 ℃,48 h)、酸解(pH 1.0,38 ℃,4 d)和超声(280 W,30 min)3种处理条件下GBVs的释放规律,利用电子鼻和顶空固相微萃取-气质联用(HS-SPME-GC-MS)技术对释放得到的GBVs物质进行鉴定。结果显示,3种处理得到的GBVs的种类及含量均有较大的差异。具体表现为：在数量上,超声处理共检出16种键合态香气物质,酸类是键合态组分中含量最高的物质；酸法水解后共检出22种键合态香气物质,主要为酸类和其它类物质；酶法水解后共检出32种键合态香气物质,主要为酯类、醇类和酸类物质。此外,对发酵红枣汁特征性香气成分进行了香气活度值OAV值分析,发现大马士酮和壬醛对发酵红枣汁香气起主要贡献作用。超声处理和酸解处理主要释放发酵红枣汁的醛酮类物质,酶解处理则主要释放发酵红枣汁的酯类、醇类和醛酮类。因此,β-D-葡萄糖苷酶酶解处理有利于释放更多种类的键合态香气化合物。

Abstract:

Lactic acid bacteria fermentation changed the aroma composition of jujube juice, which may be related to the release of glycosidically bound volatiles (GBVs). The GBVs of fermented jujube juice was obtained by adsorption and elution with Amberlite XAD-2 resin, and the release regularity of GBVs was investigated under three treatment conditions: β-D- glucosidase enzymolysis (38 ℃, 48 h), acid hydrolysis (pH 1.0, 38 ℃, 4 d) and ultrasound treatment (280 W, 30 min), respectively, by electronic nose and headspace solid-phase microextraction-gas chromatography-mass spectrometry (GC-MS). The results showed that the types and contents of GBVs obtained by the three treatments were quite different. The specific manifestations were as follows: in quantity, a total of 16 aroma compounds were identified by ultrasonic treatment, and acids were the most abundant aroma compound. A total of 22 aroma compounds, mainly including acids and other components, were identified after acid hydrolysis of bound components compared to 32 ones with enzymatic hydrolysis, mainly including esters, alcohols and acids. In addition, the valuable aroma components of fermented jujube juice were analyzed by odor activity value (OAV), and it was found that damascenone and nonanal played a major role for the aroma of fermented jujube juice. Aldehydes and ketones were the main aroma components of fermented jujube juice by ultrasonic treatment and acidolysis treatment, while the esters, alcohols, aldehydes and ketones were the main aroma components for enzymatic hydrolysis. Therefore, β-D- glucosidase enzymatic treatment was more conducive to the release of many bonded aroma components in fermented jujube juice.