Concentrations differences of microalgal extracellular polymeric substances as edible coating in shelf-life extension of Fragaria spp.

Abstract

Fruits belong to a group of perishable commodities that will undergo degradation over short period of time after harvesting. Strawberry (Fragaria spp.) is a fruit with high water contents and need approximately five months from planting to harvesting. Fragaria spp. has a short shelf-life, a week in freezer (0-4°C) and two days in room temperature. Edible coating is one of the substances for slowing degradation process of fruit. This research was conducted to reach better understanding about edible coating made from Extracellular Polymeric Substances (EPSs) produced by microalgae Chlorella sp. cultivated in modified BG-11 medium. Edible coating formulated with 30% and 50% EPSs and applied on Fragaria spp. Control and coated strawberries were incubated in room temperature (37°C) and low temperature (3°C). The EPS yield of Chlorella sp. is 2,628 µg/g biomass. Water contents, vitamin C contents, decay index, and mass shrinkage was measured to determine effectiveness of edible coating. Accelerated Shelf Life Testing (ASLT) method with Arrhenius model was conducted to determine the storage time of Fragaria spp. that is coated with EPSs from microalgae. The result of this research was that edible coating from 50% EPSs Chlorella sp. in temperature 3°C showed the most optimal result than control and another treatment. Thus, this formulation was able to prolong fruit's shelf-life, especially on Fragaria spp. Coated Fragaria spp. reached decaying phase on ten days in low temperature and four days in room temperature. Coated Fragaria spp. had low water contents, high vitamin C contents, and low mass shrinkage.