Inhibitory effect of natural anti‐browning agents on polyphenol oxidase from pearl brinjal ( Solanum melongena var. serpentinum L.)

Abstract

Food browning is an undesirable phenomenon caused by the enzyme polyphenol oxidase that led to food wastage and eventually deteriorates the market value. In this study, the effect of natural inhibitors including red grapefruit, key lime, red chili pepper, and pineapple on polyphenol oxidase extracted from pearl brinjal was investigated. As for the effects of chemical inhibitors, L-cysteine exhibited stronger inhibition (IC50: 0.29 mM), as compared to citric acid (IC50: 50.73 mM). Meanwhile, red chili pepper was found to be the best natural inhibitor (IC50: 65.78 mg/ml), followed by red grapefruit, key lime, and lastly pineapple (IC50: 145.90, 206.78, and 216.86 mg/ml, respectively). All the natural inhibitors showed an increase in inhibition percentage along with an increase in inhibitor concentration (13.33 ± 3.82–48.93 ± 3.05%). The present findings suggested the potential of red grapefruit, key lime, red chili pepper, and pineapple to replace chemical inhibitors in the future to inhibit browning. Novelty impact statement The use of natural inhibitors does safeguard health-concerned consumers on obtaining both browning and chemical-free food. Red chili pepper was found to be a potential natural inhibitor to replace chemical inhibitors to inhibit the browning of pearl brinjal. Both red chili pepper and pearl brinjal are also compatible in terms of palatability, which makes them a good combination for food industries to produce for consumers to taste with minimal browning.