Abstract: In order to ascertain the major quality characteristics of macadamia nuts produced in Guangxi so as to establish a comprehensive evaluation method for its economic characteristics, 14 samples of macadamia nuts from major production areas in Guangxi were selected to determine indicators of superior nuts and quality indexes including the composition and content of fatty acids, amino acids and mineral elements in kernels. The quality of macadamia nuts was comprehensively evaluated by factor analysis (FA), cluster analysis (CA) and orthogonal partial least squares-discriminant analysis (OPLS-DA). The results showed that there were significant differences in the quality of macadamia nuts from different producing areas, and marketable fruit percentage was less than 97% for 42.9% of orchards in Guangxi, suggesting the necessity of strengthening orchard management. The main unsaturated fatty acids were oleic acid and palmitoleic acid, the main amino acids in hydrolyzed macadamia nuts were medicinal amino acids, and the contents of phosphorus and calcium were relatively higher than other mineral elements. Systematic cluster analysis showed that the 14 samples could be divided into three categories, and that 22 indicators including marketable fruit percentage, fat, protein, palmitic acid, heptadecanoic acid, stearic acid, arachidic acid, oleic acid, linolenic acid, eicosatrienoic acid, aspartic acid, threonine, serine, glutamic acid, alanine, valine, isoleucine, leucine, tyrosine, phenylalanine, lysine, and phosphorus were found to be useful to discriminate samples from different geographical origins. Factor analysis was used to establish the evaluation model for the economic traits of macadamia nuts, which had very high predictive accuracy verified by stepwise regression analysis. Category 3 (containing samples 12 and 14) had the best quality, followed sequentially by category 1 (containing samples 1, 2, 3, 6, 7, 8, 9, 10, 11, and 13), and category 2 (containing samples 4 and 5). This study can provide a basis for accurate evaluation of macadamia nut quality, establishment of quality evaluation criteria and quality control of macadamia nut produced in Guangxi.

Key words: Macadamia integrifolia; fruit; quality analysis; comprehensive evaluation