Optimal conditions for anthocyanins extracting from some food wastes

The aim of this study is to determine the optimum conditions for anthocyanins extracting from the peels of eggplant, onion, red cabbage and pomegranate. The effects of solvent type, ratio of the raw material to solvent, temperature, pH, duration of extraction, and absorbance readings to the range of wavelengths ۳۶۰-۷۰۰ nm were examined. For the solvent types, the results showed that the best extraction solvent was ethyl alcohol acidified with citric acid at a concentration of ۵% with a pH of ۲, followed by ethyl alcohol acidified with hydrochloric acid, then the absolute ethyl alcohol in the third place, and the least was water and acidified water as an extraction solvent. The highest amount of pigment was found in pomegranate peels using ethyl alcohol acidified with citric acid, a value of ۷۶.۱۰ mg ۱۰۰ g-۱ at a wavelength of ۳۹۰ nm, while the water solvent exhibited the lowest amount extracted pigment of ۵.۴۴ mg ۱۰۰ g-۱ at a wavelength of ۵۴۰ nm in red cabbage peels. The optimum raw/solvent ratio for extraction was ۴۰:۱ weight (W)/ volume (V) in onion and eggplant peels with a value of ۱۲۲.۰۱ and ۷۹.۷۲ mg ۱۰۰ g-۱, respectively, while the ratio of ۱:۲۰ (W/V) was the best for extracting both cabbage leaves and pomegranate peels. Temperature results indicated that the highest amount of anthocyanins is extracted at ۶۰ °C for red cabbage, pomegranate and eggplant, with a value of ۷۰.۵۶, ۹۶.۲۱ and ۱۱۸.۴۳ mg ۱۰۰ g-۱, respectively. On the other hand the temperature of ۵۰°C was the best for extracting onion peels, with pigment amount of ۱۲۲.۰۱ mg ۱۰۰ g-۱. Finally, the best time duration to extract the pigment is ۶۰ minutes in all raw materials included in the study.

کلیدواژه ها:

Anthocyanin ، Extract ، Food ، Fruit ، Wastes