Efficacy of ascorbic acid, citric acid, ethylenediaminetetraacetic acid, and 4-hexylresorcinol as inhibitors of enzymatic browning in osmo-dehydrated fresh cut kiwis

The aim of the present study was to investigate the effects of osmo-dehydration using four anti-browning agents (ascorbic acid (AA), citric acid (CA), EDTA and 4-Hexylresorcinol (4-HR) on physico-chemical, color and browning phenomenon in commonly consumed fresh cut kiwis (var. Hayward) of Kashmir region. Osmo-dehydration was carried out using 60 % glucose + 1 % calcium chloride solution under ambient conditions and concentration of anti-browning agents- ascorbic acid, citric acid, EDTA and 4-HR were varied between 0.5 and 2.5 %, 0.5-1.5 %, 0.25-1.25 and 0.01-0.05 %, respectively, using central composite rotatable design. Browning index, polyphenol oxidase activity, and yellowness (b*) were significantly (p < 0.05) decreased, whereas brightness (L*) and greenness (-a*) were significantly (p < 0.05) increased with the increase in concentration of each anti-browning agent. Out of all the anti-browning agents tested, 4-HR recorded dominant linear effect on each parameter. Design expert predicted optimum concentrations of AA as 2 %, CA as 1.3 %, EDTA as 1 % and HR as 0.04 % for reducing browning and preserving color parameters during osmotic-dehydration of kiwifruit slices. Kiwifruit slices osmo-dehydrated with optimum concentration of anti-browning agents showed significantly (p < 0.05) higher water loss and lower water activity than fresh kiwifruits. Anti-oxidant activity and ascorbic acid of kiwi slices increased significantly (p < 0.05) when osmo-dehydrated with optimum concentration of anti-browning agents than kiwi slices osmo-dehydrated without anti-browning agents.