Elaboration of orange juice concentrate by vacuum‐assisted block freeze concentration

Abstract

Vacuum-assisted freeze concentration is a technology allows produces high-quality concentrates and thus achieves the protection of heat-labile components in fresh samples. The aim of this study was to investigate the use of vacuum-assisted block freeze concentration in the elaboration of orange juice. Fresh juice was unidirectional frozen at −20 °C for 12 hr and vacuum was performed at 80 kPa. The results showed, 20 min of suction, an increased in concentrated fraction and ascorbic acid content by 4.4 and 4.1 times, respectively, compared with the fresh juice. The cryoconcentrates were darker than the initial sample, with ΔE* values >10 CIELAB units in all treatments. In addition, achieved high values with 84% in efficiency and 35% of concentrate. It was concluded that vacuum in freeze concentration of orange juice was effective for obtaining a high-quality concentrate with a higher concentration of solids and ascorbic acid content compared with the fresh sample. Practical applications The block freeze concentration assisted by vacuum allows producing an orange juice concentrate with excellent physicochemical properties (increase solid content, darker color, and higher ascorbic acid content compared with the initial sample), which can draw attention to consumers looking foods rich in bioactive components for a healthy life. The vacuum as an assisted technique improve the process parameters of block freeze concentration, obtaining promissory results for adaptability to commercial scale in the elaboration of concentrated orange juice.