Chemical Composition in Kernels of Ten Grafted Pecan (Carya illinoensis) Varieties in Southeastern China

Abstract

As woody oil crop, pecan [Carya illinoinensis (Wangenh.) K. Koch] may be a solution to the shortage of edible oil in the future. In this study, fruit traits, kernel nutrition and fatty acid composition of 10 pecan varieties were determined to assess the potential of pecans for exploitation as edible oil, as well as to further screen varieties that could be used as edible oil resources and to understand their development prospects for cultivation in mountainous hills. The study showed that all the fruit trait indicators measured, including green-fruit weight (mean 28.47 g), nut weight (10.33 g), kernel weight (5.25 g), nut percentage (36.83%) and kernel percentage (50.50%), showed highly significant differences among the 10 varieties. Among the main nutritional indicators of the kernels, the crude fat content was stable (mean 70.01%) with non-significant differences, while protein (67.50 mg·g−1), soluble sugar (10.7 mg·g−1) and tannin (6.07 mg·g−1) showed highly significant differences between varieties. The oil percentage of nuts (kernel percentage * crude fat) averaged 35.36%, with highly significant differences between varieties. The fatty acid composition was dominated by unsaturated fatty acids (mean 91.82%), with unsaturated fatty acids being 11.24 times more abundant than saturated fatty acids. Among the monounsaturated fatty acids, oleic acid was the highest (mean 70.02%), with highly significant differences between varieties, followed by cis-11-eicosanoic acid (0.25%), with non-significant differences between varieties; among the polyunsaturated fatty acids, linoleic acid was the highest (19.58%), followed by linolenic acid (0.97%), both of which showed highly significant differences between varieties; monounsaturated fatty acids were 2.42 times more abundant than polyunsaturated fatty acids. Compared to other oilseed crops, pecan has the potential to produce “nutritious, healthy and stable” edible oil, while its wide habitat and good productivity benefits offer broad prospects for development in the hills and mountains of subtropical China.