Gravitational assisted three-stage block freeze concentration process for producing enriched concentrated orange juice (Citrus sinensis L.): Multi-elemental profiling and polyphenolic bioactives

Abstract

A three-stage block freeze concentration process using minimal instrumental apparatus was studied to concentrate minerals and polyphenols in orange juice, obtaining one cryoconcentrate and one ice fraction at each stage. The process parameters were designed, and the cryoconcentrates and ice fractions were analyzed for physicochemical properties, polyphenolic composition, and mineral profile. The three-stage process obtained high concentrations of polyphenols and minerals in orange juice, with the third stage cryoconcentrate obtaining a 429% increase in polyphenols compared to the initial juice. This cryoconcentrate had the highest K, Mg, and Ca levels, while most of the minerals were significantly retained in the ice fractions. The antioxidant activity of concentrated juices increased sequentially by 168, 272, and 343% across process stages. The last two stages of cryoconcentration using only gravitational force led to high concentrations of polyphenols, minerals, soluble solids, and vitamin C in concentrated juices. • The three-stage block freeze concentration process was applied for the enrichment of the orange juice. • Process parameters showed excellent performance and efficiency. • The three-stage process retained a high concentration of polyphenols and minerals in the samples. • Concentrated orange juice showed high concentrations of soluble solids, vitamin C and color intensity.