Valorization of persimmon calyx, an industrial biowaste, as a potential resource for antioxidant production

In general, one-third of food produced worldwide is reported to be wasted during processing or distribution, which is one of the major causes of environmental pollution. A biorefinery strategy based on food waste, which uses food waste as a raw material for biomaterial production without landfilling, is attracting attention recently. Prior research on potential raw materials and process design is required to realize this. In particular, plant-based food wastes are valuable as feedstock for antioxidant production due to their abundant phytochemicals with pharmacological benefits. In this study, persimmon calyx (PC) has been used as a potential resource for antioxidant production. We designed the extraction process to efficiently recover antioxidants from PC using a response surface methodology. As a result of the fundamental experiment, the methanolic extracts showed the highest total phenol recovery (TPR, 21.5 mg/g biomass) and total flavonoid recovery (TFR, 13.6 mg/g biomass) from PC compared to several solvents. Based on the methanol extraction process, solvent concentration, temperature, and time were optimized by statistical models as follows: 71.5% methanol, 25 °C temperature, and 2.3 h extraction time. Under these conditions, TPR and TFR were determined to be 21.7 ± 0.5 mg (predicted TPR = 20.4 mg) and 11.7 ± 1.0 mg (predicted TFR = 11.2 mg) per g PC, respectively. The prepared PC extract showed IC50 values of 141.3 ± 8.8 and 42.9 ±3.2μg/mL through ABTS and DPPH assays, respectively. This study highlights the utilization feasibility of PC as a sustainable resource for antioxidant production through process optimization. [Display omitted] •Food waste-based biorefineries are a key strategy to protect the environment.•Persimmon calyx (PC), an industrial biowaste, was used to produce antioxidants.•Optimal extraction conditions were derived as 71.5% methanol, 25 °C temperature, and 2.3 h time.•Under optimal conditions, 21.7 mg of phenolics can be produced from 1 g of PC.•This study highlights the utilization feasibility of PC as a resource for biochemical production.