The structure changes of water-soluble polysaccharides in papaya during ripening

Papaya is a fruit mainly grown in tropical and subtropical regions. The structural changes of polysaccharides are highly involved in the organoleptic property change of papaya. However, it remains unclear how the structure characteristics of water-soluble polysaccharides are changed during postharvest ripening. It is interesting to work on this topic. In this work, the dominant water-soluble polysaccharide in papaya was purified. It was identified to be α-(1 → 4)-D-galacturonan by NMR. It remained stable during postharvest ripening. β-(1 → 4)-D-galactan was only detected in fully green papaya. Once the postharvest ripening initiated, this polysaccharide was rapidly degraded. There were no significant differences in the structure changes of water-soluble polysaccharides for the naturally ripening papaya and ethylene-treated papaya. These results extended the understanding about the relationship between polysaccharide structure and papaya ripening during postharvest storage.