关键词: 长柄扁桃, 毛乌素沙地, 脂肪酸, 变异

Abstract:

[Objective] Amygdalus pedunculata is naturally distributed in Mu Us Desert. The tree has strong resistance, and its kernel has high oil content, therefore A. pedunculata is classified as a new type of woody edible oil plant resources. [Method] Understanding nutritional quality characteristics of A. pedunculata kernel, particularly fatty acids, will provide scientific basis for the breeding. In this paper, 31 A. pedunculata representative samples were selected according to their nut characteristics from Mu Us Desert. The variations of crude fat content and fatty acid composition were studied. The samples were extracted using Soxhlet extraction and the GC analysis based on AOAC996.06 method was used to analyze the fatty acid composition and oil content. [Result] The results showed that the crude fat content ranged from 46.08% to 61.61%, the average content was 54.58%. The kernel oil contained seven kinds of fatty acids: Palmitic, Palmitoleic, Stearic, Oleic, Linoleic, α-Linolenic and cis-11-Eicosenoic, among which the major fatty acids were oleic acid (34.94%) and linoleic acid (15.87%). The percentage of total unsaturated fatty acids in the oil varied from 96.44% to 98.31%, while percentage of oleic acid and linoleic acid content was as high as 93.09%. The percentage of saturated fatty acid was reached to 3.56%, and its major composition was palmitic acid. The lipid content was relatively stable, and the variation coefficient was only 8.10%. However fatty acid content changed greatly, coefficients of variation was 37.02% for linoleic acid and 8.77% for oleic acid. The variation coefficient of fatty acid components among different individuals in A. pedunculata population from high to low was linolenic acid (37.02%), cis-11-Eicosenoic (29.34%), stearic acid (25.39%), palmitoleic acid (21.83%), linoleic acid (20.34%), palmitic acid (14.44%), oleic acid (8.77%). This result indicated that the content of oleic acid and linoleic acid was not only high, but also stable, while the content of linolenic acid and cis-11-Eicosenoic was comparatively low and unstable. The total crude fat content was significantly correlated with the content of oleic acid, linoleic acid and unsaturated/saturated ratio, with the correlation coefficient of 0.68, 0.70, and 0.74, respectively. The total crude fat content was highly and negatively correlated with the content of linolenic acid and SFA, with the correlation coefficient of -0.52 and -0.68. MUFA was significantly correlated with the content of oleic acid, while PUFA was significantly correlated with the content of linoleic acid and the correlation coefficient were closed to 1.00. [Conclusion] A. pedunculata nuts have high content of crude lipid. The fatty acid composition was relatively simple, and mainly of oleic acid and linoleic acid. The content of oleic acid and linoleic acid was relatively stable, and positively correlated with the total crude fat content. These results would provide some guidance for breeding new oil varieties.

Key words: Amygdalus pedunculata, Mu Us desert, fatty acid, variation