Three novel peptide sequences YGIKVGYAIP, GGIF, and GIFE from papain-generated protein hydrolysate of palm kernel cake proteins were used for stability study against ACE, ACE-inhibition kinetics, and molecular docking studies. Results showed that peptide YGIKVGYAIP was degraded, and its ACE-inhibitory activity decreased after 3 h pre-incubation with ACE, while peptides GGIF and GIFE were resistant. However, although the ACE-inhibitory activity of GIFE increased during this time, the ACE inhibitory activity of GGIF decreased after pre-incubation with ACE, indicating that peptide. YGIKVGYAIP and GGIF are substrate-type, whereas GIFE is a true-inhibitor type. Peptide YGIKVGYAIP showed the lowest Ki (0.054 mM) in the inhibition kinetics study compared to GGIF and GIFE, with Ki of 1.27 m M and 18 mM, respectively. In addition, YGIKVGYAIP revealed the lowest Km and Vmax and higher CE in different peptide concentrations, implying that the enzyme catalysis decreased, and peptides had some binding affinity to the enzyme in lower concentrations, which led to reduced catalytic ability. Furthermore, YGIKVGYAIP showed the lowest docking score of -14.733 and 21 interactions with tACE, while GGIF revealed the higher docking score of -8.006 with 15 interactions with tACE.
Natural slice jam from the citrus peel is a product that enhances the economic value of the waste of citrus fruit peel. The goal of the study was to improve a recipe for a natural jam made entirely from citrus peel and shaped into a square to make it a more convenient and ready-to-eat product. A two-level factorial design was used to investigate the effects of four independent variables; X1: concentration lemon peel (Citrus limonum), X2: concentration orange peel (Citrus sinensis), X3: storage temperature, and X4: sugar. Sample processing was performed at range between 10 and 20 g of lemon and orange peel concentration and sugar (6-10 g) at a constant gelatine weight of 1.6 g. The samples were stored at 2 °C and 25 °C, and textural properties (hardness and adhesiveness) were evaluated. Results indicated that concentrations of lemon peel (10 g), orange peel (15 g), sugar (8 g), and storage temperature (13.5 °C) significantly influenced jam texture. Interaction effects, including AD, BC, and BD, were notable. Optimal conditions favoured higher orange peel concentration. Validation experiments confirmed a maximum 10 g lemon peel concentration with an error below 10%. Despite room temperature storage causing textural quality deterioration due to syneresis, this study contributes valuable insights for food industry applications of natural products, greener and more cost-effective. The factorial design approach effectively optimized citrus peel slice jam formulation, demonstrating the significance of applied sciences in addressing practical challenges.
Fruit and vegetable wastes are linked to the depletion of natural resources and can pose serious health and environmental risks (e.g. eutrophication, water and soil pollution, and GHG emissions) if improperly managed. Current waste management practices often fail to recover high-value compounds from fruit wastes. Among emerging valorization methods, the utilization of fruit wastes as a feedstock for microalgal biorefineries is a promising approach for achieving net zero waste and sustainable development goals. This is due to the ability of microalgae to efficiently sequester carbon dioxide through photosynthesis, utilize nutrients in wastewater, grow in facilities located on non-arable land, and produce several commercially valuable compounds with applications in food, biofuels, bioplastics, cosmetics, nutraceuticals, pharmaceutics, and various other industries. However, the application of microalgal biotechnology towards upcycling fruit wastes has yet to be implemented on the industrial scale due to several economic, technical, operational, and regulatory challenges. Here, we identify sources of fruit waste along the food supply chain, evaluate current and emerging fruit waste management practices, describe value-added compounds in fruit wastes, and review current methods of microalgal cultivation using fruit wastes as a fermentation medium. We also propose some novel strategies for the practical implementation of industrial microalgal biorefineries for upcycling fruit waste in the future.