The Impact of Formalin on Postharvest Quality, Shelf Life, and Nutritive Properties of Carrot, Papaya, Plum, Apple Plum, and Guava

Abstract

As per the news and articles published in mass media in recent years, the usage of formalin in fruits and vegetables has become a worrisome condition in Bangladesh. In this context, this study was conducted to observe the effect of formalin on postharvest quality, shelf life, and nutritional profile of carrot, papaya, plum, apple plum, and guava. Fruits and vegetables sample were treated with different concentrations of formalin solutions (1%, 10%, 20%, and 30%) in two different modes (dipping and spraying) and stored for seven days. Physical parameters (color, texture, and flavor), weight loss, and shelf life were observed on every alternate day during the study period. Furthermore, 20% formalin-treated samples were used to find out the changes in nutritional profile (moisture, ash, carbohydrate, fat, and protein), pH, and vitamin C content. The study results revealed that different concentrations of formalin and treatment methods (dipping and spraying) did not bring up any positive effect in increasing the shelf-life and physical characteristics of selected fruits and vegetables during storage. Moreover, formalin treatment with higher concentration went in faster deterioration in color, texture, and flavor of samples compared to the control. The weight loss of fruits and vegetables is not dependent on formalin application. Formalin treatment worked negatively on the shelf life of samples. A significant reduction (P<0.05) trend on some nutritional parameters (carbohydrate, protein, fat, vitamin C) was observed in formalin-treated apple plum and guava when compared with the control. No significant differences in the pulp pH content were seen as a result of formalin treatment. The overall results suggest that formalin is not a useful preservative to improve the post-harvest qualities and shelf-life of carbohydrate-rich fruits and vegetables at any concentration and mode of application and it has also a negative effect on the nutritional properties of fruits and vegetables.