Department of Food Science and Technology, College of Agricultural and Environmental Sciences, The University of Georgia, 100 Cedar Street, Athens, Georgia 30602-2610, United States.
J Agric Food Chem. 2011 Nov 23;59(22):12083-92. doi: 10.1021/jf203187v. Epub 2011 Oct 27.
Uncharacteristic of most whole foods, the major component of tree nuts is lipid; surprisingly, information on the lipid constituents in tree nuts has been sporadic and, for the most part, not well reported. Most published papers focus on only one nut type, or those that report a cultivar lack a quality control program, thus making data comparisons difficult. The present study was designed to quantify the healthful lipid constituents of 10 different types of commercially important tree nuts (i.e., almonds, black walnuts, Brazil nuts, cashews, English walnuts, hazelnuts, macadamias, pecans, pine nuts, and pistachios) according to standardized, validated methods. The total lipid content of each nut type ranged from 44.4 ± 1.9% for cashews to 77.1 ± 1.7% for macadamias. As expected, the major fatty acids present in the tree nuts were unsaturated: oleic (18:1 ω9) and linoleic (18:2 ω6) acids. A majority of the lipid extracts contained <10% saturated fatty acids with the exceptions of Brazil nuts (24.5%), cashews (20.9%), macadamias (17.1%), and pistachios (13.3%). The total tocopherol (T) content ranged from 1.60 ± 1.27 mg/100 g nutmeat in macadamias to 32.99 ± 0.78 in black walnuts. The predominant T isomers in the nut types were α- and γ-T. Tocotrienols were also detected, but only in 6 of the 10 nut types (i.e., Brazil nut, cashews, English walnuts, macadamias, pine nuts, and pistachios). In most cases, total phytosterol contents were greater in the present study than reported in peer-reviewed journal papers and the USDA National Nutrient Database for Standard Reference, which is attributed to total lipid extraction and the inclusion of steryl glucosides in the analysis; the levels were highest for pistachios (301.8 ± 15.4 mg/100 g nutmeat) and pine nuts (271.7 ± 9.1 mg/100 g nutmeat). Minor sterols were also quantified and identified using GC-FID and GC-MS techniques.
与大多数全食物不同，树坚果的主要成分是脂质；令人惊讶的是，关于树坚果脂质成分的信息一直很零散，而且在很大程度上没有得到很好的报道。大多数已发表的论文仅关注一种坚果类型，或者那些报告特定品种的研究缺乏质量控制程序，因此很难进行数据比较。本研究旨在根据标准化、经过验证的方法，定量分析 10 种商业上重要的树坚果（杏仁、黑胡桃、巴西坚果、腰果、山核桃、澳洲坚果、胡桃、美洲山核桃、山核桃、松子和开心果）的有益脂质成分。每种坚果类型的总脂质含量范围从腰果的 44.4±1.9%到澳洲坚果的 77.1±1.7%。正如预期的那样，树坚果中存在的主要脂肪酸是不饱和脂肪酸：油酸（18:1 ω9）和亚油酸（18:2 ω6）。大多数脂质提取物的饱和脂肪酸含量低于 10%，只有巴西坚果（24.5%）、腰果（20.9%）、澳洲坚果（17.1%）和开心果（13.3%）除外。总生育酚（T）含量范围从山核桃中的 1.60±1.27mg/100g 果仁到黑胡桃中的 32.99±0.78mg/100g 果仁。在坚果类型中，主要的 T 异构体是 α-和 γ-T。生育三烯酚也被检测到，但只在 10 种坚果类型中的 6 种（即巴西坚果、腰果、山核桃、澳洲坚果、松子和开心果）中检测到。在大多数情况下，本研究中的总植物甾醇含量高于已发表的同行评议期刊论文和美国农业部国家营养数据库标准参考值，这归因于总脂质提取和甾醇糖苷在分析中的包含；含量最高的是开心果（301.8±15.4mg/100g 果仁）和松子（271.7±9.1mg/100g 果仁）。使用 GC-FID 和 GC-MS 技术还定量和鉴定了少量甾醇。
