Fruit peels are often produced as a byproduct of processing and are usually disposed of as industrial waste. We conducted a study on the effective use of peels for the food industry using persimmons and mandarins as models. The production of persimmon and mandarin peel pastes, their flavor components, color, polyphenol contents, physical properties, and uses in foods (jam, cookies, and madeleines) were studied. The effects of heat treatment for sterilization, to effectively use persimmon and mandarin peels, were also investigated. The amount of water added to produce the optimum persimmon and mandarin peel pastes was 0.5× and 2.0× the weight of the respective peel samples. The main flavor components, as per GC-MS spectra of persimmon and mandarin peel pastes, were 4 and 1, respectively. The Folin assay showed the polyphenol contents of persimmon and mandarin pastes as 33.9 mg and 236.3 mg of catechin equivalent per 100 g of fresh fruit, respectively. The persimmon paste specifically improved the physical properties of cookies, whereas the mandarin paste was well suited to all the processed food forms. Heat treatment for sterilization decreased cohesiveness but increased breaking strength and adhesiveness in persimmon and mandarin pastes.
Keywords: folin assay; fruit peel pastes; mandarin; persimmon.
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