Analysis and evaluation of seed kernel oil content and fatty acid components of Acer truncatum in Central China
Minhao Han1,2, Liping Yan1,*, Yan Liang1, Yinhua Wang1, Fei Ren1, Dejun Wu1
(1. Shandong Academy of Forestry Sciences/ Shandong Provincial Key Laboratory of Forest Genetic Im-provement, Shandong Jinan 250014, China; wel2080@163.com (M.H.); 1755851513@qq.com (Y.L.); wyh_0322@163.com (Y.W.); lkrenfei@163.com (F.R.); sdlky412@163.com (D.W.)2. Shandong Agicultural University, Shandong Taian 271000, China. * Correspondence: ylp_982@163.com; Tel.: +86-13156103091
Abstract: In order to screen out the high-oil Acer truncatum germplasm resources so as to improve the yield and value of seed oil, this experiment was carried out by analyzing and evaluating a total of 70 samples from natural populations of A. truncatum in nine Central Plains of China, the results were subjected to nested ANOVA and correlation analyses, as well as a comprehensive evaluation of the various groups using principal component analysis and the affiliation function method. The findings demonstrated that the 70 samples ranged in seed kernel oil content from 14.43% to 50.11% (average 33.11%), and that the major fatty acid fractions had coefficients of variation that ranged from 24.13% to 33.40%, with differences between them being significant. According to correlation analysis, latitude, temperature, and precipitation had a greater impact on the seed kernel oil content than they did on the relative content of fatty acid fractions. Altitude, temperature, and precipitation were the primary causes of changes in the content of fatty acid fractions. The principal component analysis reduced the nine indexes to two principal components with a cumulative contribution rate of 84.29%, and ranked them according to the comprehensive evaluation value obtained from the principal component analysis and the transformation of the affiliation function. The analysis screened out the ten germplasm samples with the highest comprehensive quality and the three samples with the highest comprehensive evaluation value.
Keywords: Acer truncatum ; oil content; fatty acid components; neuric acid; correlation analysis
Introduction
Acer truncatum Bunge is a widely used ornamental tree species throughout the world, with lovely leaves and graceful posture. In recent years, A. truncatum has also been found to have high medicinal value; its seeds contain nearly 27% of the protein and eight essential amino acids, and its oil is rich in unsaturated fatty acids, with a content of more than 90%[1-3]. Neurotic acid, also known as shark’s acid, is a long-chain unsaturated fatty acid found in seed kernel oil that has been shown to improve cellular vitality, restore the activity of brain cell endings, and have a therapeutic effect on memory loss, cerebral palsy, and other cerebral disorders, as well as a skin whitening effect[4-6]. Since it is difficult to extract, expensive, and low yield, neurotic acid is typically only obtained from the deep-sea brains of sharks and other mammals. However,A. truncatum seed oil has a high concentration of neurotic acid (up to 4%–9%), which represents a significant new source for the sustainable use of neurotic acid [7-9].
Liu Xiangyi et al [10] analyzed 12 fatty acids from A. truncatum seeds and concluded that the unsaturated fatty acid content of A. truncatum oil reached more than 92%, making it suitable for use as a high-quality raw material in the manufacturing of nutritional and therapeutic oils. Wei Ming et al[11] found 44.3% oil and 16 fatty acids in the seed kernels of A. truncatum in Jiangyou, Mianyang. Qiao Q et al[12] examined 138 A. truncatum seed oils from 14 A. truncatum populations around China and found an average oil content of 28.57% and a fatty acid level of 5.76%. Wu Longkun et al [13] collected and analyzed A. truncatum seed oil from the Changwu area of Liaoning province, found 12 fatty acids, and evaluated the optimal experimental conditions, yielding the greatest oil production of 30.5%. By using fatty acid spectrum profiling and physicochemical testing, Ke Zhang et al[14] were able to identify the constituents and quality of A. truncatum oil. They were able to identify 18 fatty acids, of which the neurotic acid concentration may reach 8%, and 3.51% of flavonoids that can be employed as anti-alcohols. During the maturity phase of A. truncatum seeds, a total of 17 fatty acid components were found by Dai Yanman[15] et al. They came to the conclusion that by testing the seeds at various times throughout the year, the A. truncatum seed kernels would achieve their peak oil and fatty acid concentration by the end of October.
There are currently more studies on woody oilseed species with high oil content and unique components, but there are few studies comparing the oil content and fatty acid composition of seed kernels among populations of A. truncatum . In order to lay a theoretical foundation for the selection and breeding of high-oil A. truncatum germplasm, samples from natural A. truncatum populations in the Central Plains of China were collected and their variations in oil content and fatty acid components of seed kernels were analyzed. By providing a theoretical framework for the selection and breeding of high-oilA. truncatum genetic resources, this study aims to advance the growth of the A. truncatum oil industry.
Materials and Methos
Plant Materials
A total of 70 samples were obtained from nine natural populations ofA. truncatum in the provinces of Shandong, Jiangsu, and Shaanxi through field surveys of the species’ range. The samples were obtained in October when the fruits of the A. truncatum became ripe and yellowish-brown, and they were then allowed to naturally dry in the shade for three to five days after harvesting, and then peeled off the skin by hand to obtain pure seeds for the analysis and determination of seed kernel oil content as well as fatty acid fractions. Each sampling site’s latitude, longitude, and altitude were noted, and the remaining meteorological factors were confirmed with the local meteorological agency while the samples were gathered were numbered and catalogued (Table 1).
Table 1 Geographical location and climatic conditions of 9 collection sites ofAcer truncatum