Total phenolic concentration and browning susceptibility in a collection of different varietal types and hybrids of eggplant: implications for breeding for higher nutritional quality and reduced browning.

摘要

Phenols have numerous beneficial effects on human health. Consequently, the development of new varieties with higher contents of phenols is of interest for improving the nutritional quality of egg plants (aubergines). However, the oxidation of egg plant phenols causes browning of cut surfaces and reduces quality. Relationships among, as well as the variation and heritability of, the content of phenols, ascorbic acid and soluble solids, pH, and the degree of browning and colour difference of the cut surface of flesh in 69 egg plant varieties were determined. These included landraces from different origins, commercial varieties, experimental hybrids and 4 accessions of the related Solanum aethiopicum and S. macrocarpon. Analyses of variance revealed significant differences among the materials studied for all traits considered. Concn. of phenols in S. melongena spanned a 3-fold range, although the highest (1122 mg kg-1) and lowest (134 mg kg-1) concn. were found in S. macrocarpon and S. aethiopicum, respectively. Concn. of ascorbic acid were very low, a mean 27x lower than those of phenols, and soluble solids content ranged from 3.60 to 6.60% with a pH that ranged from 5.01 to 5.93. Commercial varieties had, as a mean, a 20% lower concn. of phenols than landraces, as well as a lower degree of browning and colour difference. Positive correlations existed between phenols concn. and degree of browning (r = 0.388) and colour difference (0.477), although only 15.1 and 22.8% of the total variation in degree of browning and colour difference, respectively, could be attributed to variation in phenols. Ascorbic acid, soluble solids content and pH were not correlated to either degree of browning or colour difference. Heritability was moderate for phenols concn. (0.50) and high for degree of browning (0.71) and colour difference (0.82). Results suggest there are opportunities for the development of new varieties with a high concn. of phenols and low or moderate browning.