干燥温度对2个品种木薯嫩茎叶黄酮提取率的影响

Effects of Drying Temperature on Flavonoids Extraction Rate from Young Stems and Leaves of Two Cassava Varieties

为提高木薯嫩茎叶黄酮资源利用水平,以木薯品种SC09与SC205为研究对象,分析不同干燥温度(40~120℃)对黄酮提取率及干燥后其贮存稳定性的影响,探讨木薯嫩茎叶采后干燥收贮方法。结果表明,随干燥温度增大,总黄酮提取率先升后降再升,黄酮成分芦丁、穗花杉双黄酮或儿茶素、山奈酚、二氢黄酮甙、槲皮素提取程度依次减小。120℃与110℃分别干燥的SC09、SC205嫩茎叶,总黄酮达提取峰值,并120 d贮存期内稳定性最好。干燥嫩茎叶贮存后,二氢黄酮甙提取程度增大,其他5种成分随品种、温度增减不一;山奈酚提取率变异系数(CV)最小,其值为1.03%~6.86%,稳定性最好;110℃干燥后SC205中芦丁和山奈酚的提取程度增加最大,增加率分别为44.89%和7.27%,变异程度小(CV为6.94%、4.59%),提取率稳定性好;儿茶素、穗花杉双黄酮、槲皮素、二氢黄酮甙提取率的最大提升率分别为211.60%、17.60%、186.39%、538.08%,但贮存期内变异程度大(CV=18.47%~50.03%),不稳定。本研究还进一步提出了基于黄酮利用的木薯茎叶干燥贮存预处理方案。

To improve flavonoids resources utilization level of young cassava stems and leaves, using cassava varieties SC09 and SC205 as ob- jects, investigated the effect of different drying temperatures（40N 120 ℃ ） on the flavonoids extraction rate（ FER ） and their stability in 120 d storage period after drying, explored a right drying storage method for postharvest young cassava stems and leaves. The research showed that total FER rised first, and then fell and rised again with the increase of drying temperature. During 40～80 ℃, the total FER was obviously in- fluenced by variety and temperature, but only temperature was main factor affecting total FER during 90～120 ℃. Extract degree of flavonoids include rutin, amentoflavone or eatechin, kaempferol, hesperidin, quercetin minished in order; the effect of cassava variety on tbe extraction rate of eateehin and hesperidin was greater than that of drying temperature, but that contrary to other 4 flavonoids. Variety and temperature had a maximum impact respectively on catechin and rutin extraction rates. Whereas both of variety and temperature had a minimum impact on kaempferol extraction rate. FER reached higher levels of 1.42% and 1.53% respectively in SC09 after 120 ℃ drying and SC205 after 110 ℃ drying, and had best stability during 120 d storage period. The extraction rate of hesperidin increased after drying storage, and that of other 5 ingredients were changing with different varieties and temperatures; the coefficient variation （CV=1.03%～6.86%） of kaempferol was minimum and its stability was best; extraction rates of rutin and kaempferol in SC205 after 110 ℃ drying were maximum, whose increasing rates were 44.89% and 7.27% respectively with a small separate degree（ CV were 6.94%, 4.59% ） and good extraction stability. Maximum in- creasing rates of catechin, amentoflavone, quercetin and hesperidin were 211.60%, 17.60%, 186.39% and 538.08% respectively. However,their stabilities of extraction efficiency were poor（ CV=18.47%-50.03% ） during storage. A right drying temperature after picking youngcassava stems and leaves as flavonoids resource to be utilized depended on the target composition and cassava varieties.