Biochemical and bioactive content in fruits of walnut (Juglans Regia L.) genotypes from Turkey

Abstract

Walnuts (Juglans regia L.) are a good source of dietary minerals and contain significant amounts of potassium, phosphorus, magnesium and iron. In Turkey, walnut orchards are found in the coruh Valley and are generally composed of local varieties. Since chemical and physical properties of walnuts are very important in determining their quality, in this study, nut and kernel characteristics, fatty acid composition and phenolic composition were determined for 26 walnut genotypes collected from the valley. Total fat content was found to be between 53.75% and 71.43%, while the crude protein amount ranged from 10.21% to 20.71%. Total carbohydrates were calculated between 14.31-27.52% and ash content was found to be between 1.64% and 3.32%. The oleic acid content and linoleic acid content ranged from 18.34 to 25.58% and 37.09% to 87.51%, respectively. The linolenic acid content was determined between 5.52% and 11.03%. Our study showed that, differences in phenolic component, crude protein and fatty acid content of walnuts were caused by different growing conditions. Genotypes have a rich and stable structure in terms of fruit quality parameters, minerals, organic acids, phenolic composition, antioxidant and fatty acids amounts and amino acids. In other words, these characteristics did not show much variation in genotypes grown in the Valley. However, there was a great variation in hormone levels among genotypes. In terms of the parameters examined, GN2, GNI, ((NIS, GN24, GN25 and GN26 genotypes were determined as rich and stable genotypes.