Abstract:
This research aimed to study on effect of carboxymethyl cellulose from water hyacinth (CMCW) and salicylic (SA) for extend shelf life of rambutan cv. Rongrien. The first experiment, carboxymethyl cellulose from water hyacinth was prepared by boiling dry powder of water hyacinth in 1 and 3% of NaOH with or without 30% H2O2 bleaching and bleaching alone. The second experiment consisted of rambutan fruit coated with 0.5% CMCW, 0.5% CMCC and uncoated (control) stored at 25°C and 85% RH. The third experiment consisted of rambutan fruit coated with 1 and 2% CMCW, 1% CMCC and control stored at 13°C and 90% RH. Then, the best concentration of CMCW was used in combination with 1 mM of SA. The results showed that the best condition in preparing cellulose for CMCW synthesis was boiling with 1% NaOH without bleaching. CMCW had the same chemical functional group (FT-IR) as carboxymethyl cellulose from commercial grade (CMCC), but differed in morphology (SEM), with CMCW having rough surface and had less viscosity than CMCC. The rambutan fruit coated with 0.5% CMCW and 0.5% CMCC maintained vitamin C and reduced skin browning, but the both coatings did not affect weight loss, peel firmness, total soluble solids and titration acid. Rambutan fruit coated with 2% CMCW and 1% CMCC showed similar results in reducing weight loss and skin browning with a shelf life of 10days, while 1% CMCW coated fruit and control had a shelf life only 8 days. Coating rambutan fruit with 2% CMCW + SA was more effective than 2% CMCW or SA alone in maintaining vitamin C content and reducing PAL and PPO enzyme activities.