Recycling fruits bio-waste for Pectin methylesterase extraction and its application in food industry

Introduction: Peels and finisher pulp of fruits are the major agricultural wastes in fruit processing industries. Such agricultural wastes are the major underutilized industrial wastes, and they are hazardous to environment. Attention to utilize or recycle the fruit bio-waste is an urgent concern. The bio-waste residues of fruits are abundant sources of significant commercial enzymes such as pectinases. Pectinases are a heterogeneous group of enzymes (biocatalysts) that degrade pectins, the major plant cell wall polysaccharides. Pectinases are important commercially due to their application in textile industry and food industry, like extraction and clarification of juice, beverage and wine fermentation, vegetable oil extraction and in preparation of jams and jellies (1). Among pectinases, pectin methylesterase (PME; EC 3.1.1.11) is used to modify the functional properties of pectins. PME catalyzes the de-methylesterification of pectin by hydrolyzing the ester linkage between galacturonic acid and methanol. Modification of structural features like degree of methylesterification (DM) and the size and frequency of neighboring stretches of demethylesterified blocks, (DMBs) dictate pectin’s functionality (2). The plant PMEs hydrolyze methyl esters in a processive manner (single chain mechanism) to introduce DMBs on pectins, unlike microbial PMEs, which act in random, non-blockwise fashion (multiple chain mechanism). The well-characterized plant PMEs are in great demand to predictably generate novel specialty pectins with enhanced functionality. Keeping in view the importance of plant enzymes in food industry and waste disposal problems, the present study is proposed to utilize musk melon/mango peel and finisher pulp to produce value-added PME enzymes for future food applications. Methods: Pectin methylesterase was isolated and partially purified from peels of mango. Results & Discussions: The relative molecular weight of the enzyme was ~32,000 Da. The enzyme was characterized for different physicochemical factors to check the suitability in food industry applications. The optimum temperature and pH of the enzyme is 30 °C and 7.5 respectively. The de-methylesterified pectin thus prepared was subjected for gelation in presence of Ca2+ ions. With < 0.5% of demethylesterified pectin, stable calcium pectate gels were produced. The enzyme shows efficient gelling property and forms pectin films after drying. Conclusion: The study demonstrates the suitability of musk melon/mango pectin methylesterase extracted from biowaste in food applications with good gelling property. The partially purified enzyme from fruit peels can be used in industries for juice clarification as it decreases cloudiness, and its gelling property can also be used for processing jams and jellies. Keywords: Pectin, pectinase, pectin methylesterase, fruits biowaste, pectin gelation References Prabhudev H, Sneharani AH. Extraction and characterization of pectin methyleterase from muskmelon biowaste for pectin remodelling, J Food Biochem. 2020;44:e13237 Cameron RG, Savary B J, Hotchkiss AT, and Fishman M L. Isolation, characterization, and pectin-modifying properties of a thermally tolerant pectin methylesterase from Citrus sinensis var.Valencia. Journal of Agricultural and Food Chemistry, 2005, 53(6), 2255–2260.