Characterization of edible film from lesser yam (dioscorea esculenta lour. burkill) starch and its utilization as edible coating to strawberry (fragaria ananassa)
Daftar Isi:
- It was shown before that lesser yam (Dioscorea esculenta) polysaccharides could be utilized as basic material to create starch-based edible film. This study was aimed to determine highest lesser yam starch extraction yield and three best concentrations of lesser yam starch and plasticizer in producing good mechanical and physical characteristics of edible film, i.e. tensile strength, elongation, thickness, and water vapor transmission rate (WVTR). The application of edible coating was also done to determine the shelf life of strawberry at room temperature storage (24-26 C, RH 52%) and cold storage (4-5 C). Lesser yam starch was extracted using different concentrations of sodium metabisulfite (0, 0.02, 0.04, and 0.06%). Extraction using 0.02% sodium metabisulfite exhibited the highest yield (65.33% db) and the purest (98.50%) starch powder. Combinations of lesser yam starch (3.5, 4.5, 5.5, and 6.5%) and glycerol as plasticizer (1, 2, and 3%) was used to prepare edible film. Three best combinations were selected as the best formulation representing each physical and mechanical characteristic. The combination of 4.5%-2% was selected due to the low WVTR, 6.5%-2% due to the high tensile strength and elongation, and 4.5%-3% due to the intermediate physical and mechanical characteristics. These combinations were formulated and applied to strawberry fruits which were then stored at room temperature (24- 26 C, RH 52%) and cold storage (4-5 C) alongside with uncoated strawberries which served as control. Coated strawberry (all concentrations) stored in room temperature had three days shelf life while control had less than 36 h shelf life. Coated strawberries by combinations of 6.5% starch-2% plasticizer, 4.5%-3%, and 4.5%-2% in cold storage exhibited shelf life of 20, 24, and 26 days, respectively, whereas the control in cold storage had only 10-day shelf life.