Characterization of edible film of lesser yam (Dioscorea esculenta Lour. Burkill) starch-plasticizer added with potassium sorbate or cinnamon oil and its utilization as edible coating to strawberry (Fragaria ananassa)
Daftar Isi:
- Lesser yam starch has been used as base for edible film and coating. Potassium sorbate and cinnamon are known as strong antimicrobial agent. This research was aimed to investigate physical and mechanical characteristics of edible film from lesser yam starch-plasticizer formulations added with sorbate or cinnamon oil, and its application as coating to strawberries. In general, incorporation of either sorbate (0.15, 0.20, or 0.25%) or cinnamon oil (0.30, 0.50, or 0.70%) at higher concentration resulted in reduced tensile strength and elongation percentage with higher water vapor transmission rate. For potassium sorbate, the formulations chosen were 6.50% starch-5.50% sorbitol-0.15% sorbate (high tensile strength), 6.50% starch-5.50% sorbitol-0.25% sorbate (high elongation), and 4.50% starch-5.50% sorbitol-0.15% sorbate (low water vapor transmission rate) whereas for oil category, the selected combinations were 6.50% starch- 5.50% sorbitol-0.50% oil (high tensile strength), 4.50% starch-5.50% sorbitol- 0.30% oil (high elongation), and 6.50% starch-5.50% sorbitol-0.30% oil (low water vapor transmission rate). The selected combinations were applied as edible coating on strawberry assigned at two storage conditions: room temperature (28- 30 °C) and refrigeration temperature (5-6 °C). At room temperature storage, control samples (uncoated and coated strawberries with 4.50% starch-5.50% sorbitol) had shelf life only for 2 and 4 days, respectively. Strawberries coated with addition of sorbate exhibited shelf life of 5-6 days, and strawberries coated with addition of cinnamon oil had shelf life for 5-11 days. At refrigeration storage, shelf life of controls was 9 and 18 days while coating formulations incorporated with sorbate further prolonged shelf life of strawberries for 19-21 days, and the ones treated with cinnamon oil had shelf life for 25-26 days. Therefore, all coated strawberries had longer shelf life and more retained strawberries’ quality including lower weight loss, higher hardness, and lower microbial count, but in a higher degree for strawberries coated with incorporation of antimicrobial agent.