Influence of Hydrocolloids as Coating on Physicochemical Properties of Averrhoa Carambola L.

Abstract

Averrhoa carambola also known as starfruit is a common fruit in tropical and a rich source of minerals and vitamins. Starfruit contains high water content and easily rots thus affecting its physicochemical characteristic and diminishing its quality if stored at normal temperature. To overcome this issue, hydrocolloids can be used as a coating that acts as a protective barrier in minimizing transpiration and respiration in addition to improving the quality characteristics of starfruit. In this study, three different types of hydrocolloids namely carboxymethyl cellulose (CMC), xanthan and guar gums were used in producing coating solutions. The aim of this study is to determine the influence of hydrocolloids coating in response to the physicochemical properties of starfruit. In this study, the coating solutions that contained CMC-guar gum (CMC:GG) and CMC-xanthan gum (CMC:XG) at concentrations of 0.5% and 1.5% were prepared. All hydrocolloids were mixed and heated at 60^oC for 40 minutes with the addition of 3% glycerol.  Starfruits were dipped into solutions coating for 2 minutes, air dried and stored for 12 days at 20^oC. Weight loss, firmness, color differences, pH of starfruit, moisture content, total soluble solids, sugar concentration, ascorbic acid and total phenolic content were analyzed during 12 days of storage. Results from this study demonstrated that the combination of 1.5%CMC:1.5%GG exhibited better results in terms of weight loss with 30.67%, pH of 3.67, moisture content of 91.16%, firmness with 2017.61 N and the lowest value of total color difference. On the other hand, a similar combination exhibited an ascorbic acid content of 16.71 mg/ 100 ml and a total phenolic content of 0.0089 mg GAE of fresh sample. As a conclusion, a coating made from different combinations of hydrocolloids can be an alternative protective barrier for starfruit as it could improve the physicochemical properties as well as preserve the freshness of fruits.