糯米发酵前后成品粽子风味物质变化分析

Changes of Flavor Substances in Finished Zongzi before and after Glutinous Rice Fermentation

以糯米为原料,25~30℃非控温进行自然发酵15 d后制成粽子。利用顶空固相微萃取-气质联用法,以粽子风味物质的数量和相对含量为指标,采用单因素试验确定粽子风味物质的萃取条件,并以此萃取条件测定发酵前后粽子中的风味物质数量和相对含量,探究糯米发酵前后风味变化的原因。结果表明,适宜的萃取条件为粽子25 g,以CAR/PDMS萃取头进行萃取,萃取温度60℃、萃取时间45 min;在此萃取条件下,发酵后的成品粽子中检测到89种风味物质,相对含量为80.55%,在未发酵的糯米成品粽子中检出80种风味物质,相对含量为87.88%;糯米发酵后成品粽子的风味物质中醛类、醇类分别比发酵前增加9种、5种;醛类、酮类相对含量分别减少9.54%、3.22%,呋喃类、醇类分别增加6.86%、5.49%;单体中,相对含量增加相对较大的有2-戊基呋喃、2-己烯醛、1-己醇、2-乙基呋喃、1-丁醇、1-辛醇,减少较显著的有己醛、2-庚酮、1-辛烯-3-醇,并检出丁酸。醛类、醇类、呋喃类及酸类在种类和相对含量上的较大变化是糯米发酵前后成品粽子风味变化的主要原因。

Glutinous rice was fermented naturally 15 d at 25-30℃.After that,the rice was washed until it tasted light and wrapped into zongzi with frozen Ruo leaves.Using headspace solid-phase microextraction com-bined with gas chromatography-mass spectrometry(HS-SPME-GC-MS)and taking the quantity and relative content of flavor substances in zongzi as indicators,the extraction conditions of the flavor substances were de-termined by single factor experiment.Under the above extraction conditions,the quantity and relative content of flavor substances in fermented and unfermented zongzi were determined to explore the causes of flavor change.The results showed that the optimum extraction conditions were follows:sample 25 g,carbon/PDMS,extraction temperature 60℃,and extraction time 45 min.Under these conditions,89 flavor substances were detected in the fermented zongzi with relative content of 80.55%,while 80 were detected in the unfermented zongzi with relative content of 87.88%.Aldehydes and alcohols in the flavor substances of finished zongzi after fermentation increased by 9 and 5 kinds,respectively,compared with those before fermentation.The relative content of aldehydes and ketones decreased by 9.54%and 3.22%,respectively,and the relative content of fu-rans and alcohols increased by 6.86%and 5.49%,respectively.In the monomers,2-pentylfuran,2-hexenal,1-hexanol,2-ethylfuran,1-butanol,and 1-octanol rose relatively significantly,while hexanal,2-heptanone,and 1-octene-3-ol decreased relatively significantly,and butyric acid was detected.Varied types and relative content of aldehydes,alcohols,furans and acids were the main reasons for the flavor change of glutinous rice.