Refining of β-cryptoxanthin from the extract of Satsuma-mandarin by-products using component solvent solubility differences

Abstract

A large amount of by-product is generated from Satsuma-mandarin (Citrus unshiu Marc.) juice processing, and Satsuma mandarin is a notable source of β-cryptoxanthin. Therefore, pulp produced during sieving and centrifugation processes contains large quantities of β-cryptoxanthin. We developed a process to refine β-cryptoxanthin from raw pulp materials. First, the pulp was subjected to enzymatic degradation, and the resultant precipitate was recovered by centrifugation. The water contained in the precipitate was then replaced with acetone, and the acetone-substituted pulp was directly extracted with hexane. After removal of the hexane, the extract was sequentially separated to soluble and insoluble fractions with hexane, acetone, ethanol, and a hexane/ethanol (4:6 or 3:7) mixture at -30°. β-Cryptoxanthin was concentrated in the hexane soluble, acetone soluble, ethanol insoluble, and hexane/ethanol-insoluble fractions. Using alkaline hydrolysis, the hexane/ethanol-insoluble fraction produced non-esterified β-cryptoxanthin crystals. In the case of the isolation of β-cryptoxanthin from Satsuma-mandarin peel, after removal of essential oils in the hexane extract of dried peel under reduced pressure steam distillation, the ethanol-insoluble fraction during the sequential separation was hydrolyzed and subjected to a silica gel flash column chromatography to afford β -cryptoxanthin. The above procedure was also successfully applied to carotenoid-containing materials, and Persimmon peel produced a carotenoid mixture in high yield.