Effect of black spot infection on the chemical composition and comprehensive quality of pecan (Carya illinoinensis) kernel oil

Abstract

The changes in the chemical composition of oil from pecan kernels following infection with black spot disease were evaluated herein to determine whether the disease affects the quality of the seed oil. The findings should provide theoretical support for developing the pecan industry and enhancing the risk resistance of the industry. Oil samples from healthy and diseased pecan kernels were obtained using the squeezing method, and the bioactive substances and fatty acid composition of the two types of oil samples were compared. The degree of oxidation and deterioration of the diseased kernel oil was evaluated. Based on supervised orthogonal partial least squares-discriminant analysis, gray correlation analysis, and unsupervised factor analysis, a multivariate evaluation model was established to comprehensively score the quality of the two types of oils. The results showed that compared with the healthy kernel oil, the contents of total polyphenols and flavonoids, as well as the peroxide and acid values, were significantly increased in the diseased kernel oil. The content of oleic acid was also significantly increased in the diseased kernel oil, as was the ratio of monounsaturated fatty acids to polyunsaturated acids. In addition, no aflatoxin was detected. Multivariate analysis showed that there was no significant difference in the quality of the diseased kernel oil compared with the healthy kernel oil. Therefore, following infection, the pecan oil begins to oxidize, but this does not have a significant negative effect on the nutrients, suggesting that oil from diseased kernels has the potential to be further processed and sold as edible-grade vegetable oil.