Fruit softening in banana: correlation among stress-relaxation parameters, cell wall components and starch during ripening
1994
Kojima, K. | Sakurai, N. | Kuraishi, S. (Hiroshima Univ. (Japan))
Bananas, Musa (AAA group, Cavendish subgroup) 'Giant Cavendish', were ripened in a biotron at 25 deg C with ethylene during 4 days. Changes in mechanical properties of pulp were detected by a stress-relaxation technique. The decrease in T, the parameter for minimum stress-relaxation time, began between day 0.5 and 1, while the decrease in initial stress began between day 0 and 0.5, suggesting that the decrease in elasticity and viscosity of pulp is a crucial physical event of pulp softening. Cellulose and moisture contents were about 3 and 780 sh weight-1, respectively, which were unchanged during ripening. The decrease in starch content of cell materials and in uronic acid content of the pectic polysaccharides of the cell walls began between day 0.5 and 1. As regards the sugar composition of the hemicellulose fraction, decreases in arabinose, mannose and galactose contents began between day 0 and 0.5. The results show that the partial decrease in hemicelluloses preceded the breakdown of starch and suggest that the coordinated degradation of pectic and hemicellulosic polysaccharides and starch is the main cause for the pulp softening process
显示更多 [+] 显示较少 [-]