Comparative Analysis of Nutritional Constituents, Antioxidant and Antimicrobial Activities of Some Common Vegetable Wastes
Swagata Biswas
, Pranabesh Ghosh, Alolika Dutta, Maitrayee Biswas and Sirshendu Chatterjee*
Department of Biotechnology, Techno India University West Bengal, Kolkata, West Bengal, India.
Corresponding Author Email: sirshendu.chatterjee@gmail.com
Abstract:
Vegetables are intrinsic to a healthy diet. But the peels are discarded as food waste, unknowing of their potential as the source of bioactive compounds. The study aims to find the nutritional constituents, antioxidant and antimicrobial activity of these food wastes. Here we make a comparative investigation among the five underutilized vegetable parts namely, Solanum tuberosum (Potato peel), Cucumis sativus (Cucumber peel), Musa acuminata (Unripe Banana peel), Brassica oleracea (Cauliflower stem), Lagenaria siceraria (Bottle gourd peel). After the primary screening, including proximate and qualitative analysis, the quantification of primary and secondary metabolites as well as minerals was estimated by different standard methods. The antioxidant potential was evaluated by both DPPH and H2O2 radical scavenging assays. Antimicrobial activity was analyzed by Kirby Bauer disc diffusion method against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) strains of bacteria compared with positive and negative controls. From the proximate analysis, the highest moisture and water content were found in the peel sample of Lagenaria siceraria. Out of ten qualitative tests, protein, fatty acid, flavonoid, alkaloid and xanthoprotein were detected in all five samples. Among the quantitative estimations, Lagenaria siceraria showed the highest amount of polysaccharides (85.82±0.12 mg DE/g DW), ascorbic acid (2.48±0.14 mg AAE/g FW), thiamine (24.46±0.13 mg TE/g DW), polyphenols (86.36±0.10 mg GAE/g DW), flavonoids (49.59±0.07 mg QE/g DW), minerals like K, Ca and Mg and 72.35±0.40% inhibition by DPPH. Simultaneously a significant amount of protein (63.59±0.13 mg BSAE/g FW), the amino acid (7.84±0.02 mg AAE/g DW), minerals like Na, Zn and B and 88.76±0.10% inhibition by H2O2 were found in Cucumis sativus. At a higher concentration, all samples were exhibited significant antimicrobial activity which laid out a strong correlation with previously screened phytonutrients and antioxidants. The overall findings suggested that these underutilized vegetable parts can be utilized in the processing of potential functional foods as well as pharmaceuticals rather than thrown out as agro-waste.
Keywords:
Antimicrobial Activity; Antioxidants; Mineral; Phytonutrients; Vegetables
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