Relationship between Texture and Cell Wall Polysaccharides of Fruit Flesh in Various Species of Citrus

Abstract

Various species and cultivars of citrus were studied to determine the relationship between texture and cell wall polysaccharide content of fruit flesh. Among those tested cultivars, navel orange ( Citrus sinensis Osbeck) and hassaku ( C. hassaku Hort. ex Tanaka) were firmest, `Fukuhara orange' ( C. sinensis Osbeck) was intermediate, and satsuma mandarin ( C. unshiu Marc.) was softest. There was a 3-fold difference in firmness among the 12 citrus cultigens measured. Cohesiveness values ranged from 0.30 to 0.49 and were not correlated with fruit firmness. Sugar content in each cell wall fraction was highest in the water and EDTA fractions, followed by the hemicellulose fraction, and was lowest in the cellulose fraction. Correlation coefficients between firmness and sugar content ranged from 0.69 to 0.88 and were highest in the cellulose fraction. This study suggests that firmness of fruit flesh among the cultigens is influenced by cell wall polysaccharide composition. Chemical name used: ethylenediaminetetraacetic acid (EDTA).