Effect of lipid extraction methods on total dietary fiber and nonstarch polysaccharide contents of selected nuts and seeds.
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.
Li
B W
BW
U.S. Department of Agriculture, Food Composition Laboratory, Beltsville Human Nutrition Research Center, ARS, MD 20705, USA.
Zhao
Z
Z
Jekot
J J
JJ
D019342:Acetic Acid / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry; D004043:Dietary Fiber / Q000032:analysis / Q000378:metabolism*; D000431:Ethanol; D006368:Helianthus; D006586:Hexanes / Q000737:chemistry; D006868:Hydrolysis; D008055:Lipids / Q000302:isolation & purification; D000432:Methanol / Q000737:chemistry; D009754:Nuts / Q000378:metabolism*; D011134:Polysaccharides / Q000032:analysis / Q000378:metabolism*; D012015:Reference Standards; D012639:Seeds / Q000378:metabolism*
D004043:Dietary Fiber; D006586:Hexanes; D008055:Lipids; D011134:Polysaccharides; D002245:Carbon Dioxide; C026385:n-hexane; D000431:Ethanol; D019342:Acetic Acid; D000432:Methanol