Utilization of Spirulina platensis microalgae as edible coating to maintain quality of fresh strawberry (Fragaria sp.)

Abstract

The fruit is an important element of daily food but undergoes rapid deterioration due to their high metabolic activity. The edible coating on fruit is one alternative that can be used to improve quality and prolong shelf life. The edible coating can come from microalgae with high protein content, which is Spirulina platensis. Other materials needed are glycerol as a plasticizer to increase flexibility and elasticity and surfactant, which is carboxymethyl cellulose (CMC) as a thickener, stabilizer, and emulsifier. Strawberry (Fragaria sp.) was a sample fruit in this study. The condition of storage temperature is at the fridge temperature of about ± 4-7 °C. This study aims to obtain the appropriate microalgae concentration as the main ingredient in making edible coating to prolong strawberry's shelf life. In this study, what varied are the concentration of S. platensis microalgae, which are 0,5%, 0,75%, and 1% (w/v). There are three tests carried out: protein quantification on edible coating solution, physical properties (weight loss), and chemical properties (pH and vitamin C) on fruit. Based on this study, an edible coating that has the best effect on strawberries is 1% S. platensis with lower weight loss, pH level, and higher vitamin C content up to seven days of storage. With higher protein content, the use of 1% S. platensis with the temperature of ± 4-7 °C achieved the lowest weight loss at 5.21 ± 0.09%, the lowest pH value at 3.29 ± 0.06, and the highest vitamin C content at 37.51 ± 0.78 mg/100g in strawberries in the seventh day of storage.