ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Effect of harvest maturity on pectic substances, internal conductivity, soluble solids and gel breakdown in cold stored `Songold' plums

M. A. Taylor, E. Rabe, G. Jacobs and M. C. Dodd

Postharvest Biology and Technology Vol: 5 Issue: 4 Pages: 285-294

1995

บทคัดย่อ

`Songold' plums (Prunus salicina Lindl.) were harvested at optimum and post-optimum maturity with a flesh firmness of 64 and 44 N, respectively. After cold storage for 10 days at -0.5°C, followed by 18 days at 7.2°C, the plums were ripened for 14 days at 10°C. The fruit was analysed for soluble solids, internal conductivity, pectic composition and viscosity of water soluble pectin at eight examination stages during storage and ripening. Insoluble pectin levels declined during cold storage and ripening while soluble pectin levels increased to make up the difference. Neither harvest maturity nor storage time had a significant effect on the concentration of calcium pectate, and this pectic fraction did not appear to influence development of gel breakdown (GB). Water soluble pectin and availability of cell fluids, as indicated by viscosity and internal conductivity, respectively, indicated a high gel potential in plums of both maturities, but at different stages during storage and ripening. Significant levels of GB developed only in plums harvested at post-optimum maturity. In this fruit, significantly higher sugar levels and loss of cell membrane integrity early in storage probably enhanced formation of pectin-sugar gels as cell fluids bind with pectins in cell walls.