脱脂对不同生长期苜蓿膳食纤维含量及其提取得率的影响

Effects of Defatting on Alfalfa Dietary Fiber Content and Extractive Rate in Different Growth Stages

目的:研究脱脂对苜蓿膳食纤维含量、构成及其提取得率的影响,为该方法在苜蓿膳食纤维提取中的合理应用提供科学依据。方法:以初花期和结荚期苜蓿草粉为原料,研究脱脂前后苜蓿草粉中膳食纤维含量、构成及其提取得率的变化规律。结果:苜蓿膳食纤维以水不溶性膳食纤维(IDF)为主,开花后苜蓿IDF含量占膳食纤维总量(TDF)的90%以上;脱脂后的初花期和结荚期苜蓿草粉中,IDF含量分别达72.88%、73.62%,比脱脂前分别提高61.38%、38.12%;IDF在TDF中的比例分别由90.09%、92.82%提高至95.19%、95.71%,IDF提取得率分别达61.52%、72.11%,比脱脂前分别提高69.94%、48.62%;脱脂过程中水溶性膳食纤维(SDF)流失严重、含量降低,SDF提取得率下降92.68%和92.29%。结论:脱脂方法适用于结荚期苜蓿IDF提取原料的前处理,但不适于苜蓿SDF的提取。

【Objective】To study the effect of defatting on the content,composition and extractive rate of alfalfa dietary fiber,and to provide scientific basis for the reasonable application of defatting in alfalfa dietary fiber extraction.【Method】The changes of dietary fiber content,composition and extraction yield of alfalfa meal before and after defatting were studied with alfalfa meal at initial flowering and pod setting stages as raw materials.【Result】Water insoluble dietary fiber(IDF)was the main dietary fiber in alfalfa.After flowering,the content of IDF in alfalfa accounted for more than 90%of total dietary fiber(TDF).After defatting,the content of IDF in alfalfa meal at initial flowering stage and podding stage reached 72.88%and 73.62%respectively,which was 61.38%and 38.12%higher than that before degreasing.The proportion of IDF in TDF increased from 90.09%and 92.82%up to 95.19%and 95.71%respectively.The extraction yield of IDF was 61.52%and 72.11%respectively,which was 69.94%and 48.62%higher than that before degreasing.In the process of defatting,water soluble dietary fiber(SDF)was seriously lost and its’content decreased.The extraction yield of SDF decreased by 92.68%and92.29%at different growth stages.【Conclusion】The defatting method is suitable for the raw material pretreatment of alfalfa IDF extraction,but it is not suitable for the extraction of alfalfa SDF.