Li B W, Zhao Z, Jekot J J
U.S. Department of Agriculture, Food Composition Laboratory, Beltsville Human Nutrition Research Center, ARS, MD 20705, USA.
J AOAC Int. 1997 Jan-Feb;80(1):98-101.
Three extraction methods were used to remove lipid materials from 8 edible nuts and seeds before analysis for their total dietary fiber (TDF) and nonstarch polysaccharide (NSP) contents. Portions of ground materials were extracted by: n-hexane, followed by 80% methanol, n-hexane-acetic acid (95 + 5, v/v), and supercritical carbon dioxide. Defatted samples were gelatinized in water and incubated with amyloglucosidase; 95% ethanol was added to the hydrolyzates, and the residues were collected on tared glass crucibles. TDF was calculated according to a simplified enzymatic-gravimetric method developed in our laboratory, and NSP was determined as described by Englyst and coworkers. Dietary fiber values obtained with any of the extraction methods range from 3.47 g/100 g for cashews to 28.56 g/100 g for sunflower seeds. Nonstarch polysaccharide values range from 2.43 g/100 g for pecans to 5.56 g/100 g for peanuts. With the exception of sunflower seeds, samples extracted with supercritical carbon dioxide had lower TDF contents but similar amounts of NSP compared with samples extracted by the other 2 methods.
在分析8种可食用坚果和种子的总膳食纤维（TDF）和非淀粉多糖（NSP）含量之前，使用了三种提取方法去除其中的脂质物质。将磨碎的样品部分分别用正己烷提取，然后用80%甲醇、正己烷 - 乙酸（95 + 5，v/v）和超临界二氧化碳提取。脱脂样品在水中糊化，并用淀粉葡萄糖苷酶孵育；向水解产物中加入95%乙醇，将残渣收集在已称重的玻璃坩埚上。TDF根据我们实验室开发的简化酶重量法计算，NSP按照Englyst及其同事所述的方法测定。用任何一种提取方法获得的膳食纤维值范围为：腰果为3.47 g/100 g，向日葵籽为28.56 g/100 g。非淀粉多糖值范围为：山核桃为2.43 g/100 g，花生为5.56 g/100 g。除向日葵籽外，与用其他两种方法提取的样品相比，用超临界二氧化碳提取的样品TDF含量较低，但NSP含量相似。
