LAUSR

PurposeTo evaluate the potential of the industrial waste of Rojo Brillante persimmon as a source for value-added products. The antioxidant compounds present in persimmon industrial waste (peel and calyx) and the suitability of this bagasse to be used as a substrate second-generation bioethanol production are studied and discussed. Both value-added products would contribute to the valorization of persimmon fruit residues, which are expected to increase to a higher extent in subsequent years, thus contributing to the food industry sustainability and circular economy.MethodsAntioxidant properties were evaluated by analyzing total phenol content, soluble tannins, flavonoids and antioxidant capacity of the waste, consisting of the peel and calyx of the fresh-cut persimmon industry. In a different approach, several fermentation and saccharification processes were assayed in order to valorize the waste as a substrate for bioethanol production: direct fermentation (DF) of the waste (with water addition, sterilized or not) was carried out and compared with simultaneous saccharification and fermentation (SSF) of the waste (with and without water addition).ResultsThe amount of phenols (59.2 ± 0.4 mg AGE/100 g FW), flavonoids (7.5 ± 0.4 mg QE/100 g FW) and tannins (11.43 ± 0.08 g AGE/100 g FW), as well as the antioxidant capacity (16.67 mg TE/100 g FW) of persimmon industrial waste were in the range of the pulp values. Persimmon waste was especially rich in carotenoids: β-carotene (400 ± 7 µg/100 g FW) and lycopene (194.3 ± 0.7 µg/100 g FW), these being values higher than in the whole fruit or pulp. Bioethanol production was more successful when a simultaneous saccharification and fermentation process was directly applied on the grinded waste (0.36 ± 0.010 gethanol/gsugar), as compared to the other DF and SSF assayed.ConclusionsPersimmon waste can be considered a good candidate for obtaining value-added products. Carotenoids could be extracted from this waste, but it is recommended to develop food ingredients in the form of flours of powders to be used as functional ingredients. Persimmon waste is also recommended as a substrate for second-generation bioethanol production, either alone or mixed with other food residual biomass.