Effect of selected preservatives on nutritional indices of kidney beans (Phaseolus vulgaris)

Abstract

Preservatives are most often used to maintain the quality of foods for longer time periods. It has been reported that chemicals, which are used as preservatives have some effects (positive or negative) on the nutritive indices of foods. This research was carried out to investigate the effect of some selected preservatives on the nutritive indices of kidney beans (Phaseolus vulgaris). The matured P. vulgaris used for this research were collected in bags from the area of cultivation. Following the established research guidelines, the seeds were prepared and sent to laboratory for analysis prior to storage with selected preservatives. The selected preservatives were procured and prepared for the experimental purpose under standard protocols. The kidney beans were divided into airtight containers and labeled in group 1 to 5, which were preserved with selected preservatives; (DDVP) (sniper), birds eye pepper and Aluminium phosphide, while the fourth group was mixed with ash and the fifth group was left without mixing with any preservative to serve as control. The beans mixed with preservative were left to stay on standard research procedure for 6 months. Standard procedures were used to assess the effect of the preservatives on the proximate compositions, mineral contents, and amino acid concentrations, respectively compared with the control group, which was not mixed with the preservatives. Results of the research showed varying effects of the different preservatives on the beans mixed with preservatives when compared with the control group. There was an observed improvement on the proximate composition of the beans preserved with some of the selected preservatives while some beans were negatively affected as the preservative affected the nutritive quality as compared to control groups; same results were observed for the mineral nutrient constituents and amino acid concentrations. The observed improvements in the experimental parameters showed that the chemicals in some groups were more effective for some aspects while natural preservatives were better for other measured criteria. The effectiveness of the preservatives for a longer shelf life and stop or delay the growth of bacteria, suppress the reaction when food comes in contact with oxygen or heat, they also prevent the loss of some essential amino-acids and some vitamins enhance the food flavors and colors. The results of this study showed that some of the selected preservatives used on the kidney beans suggested that kidney beans could improve the shelf life and improve nutritive value. Key words: Preservatives, Nutrition, Nutritive index, Shelf-life, Storage, proximate analysis, amino acid, minerals