Effect of Sonication on the Functional Properties of Different Citrus Fruit Juices

ABSTRACT The present study was conducted to evaluate the effect of ultrasound on the functional properties of citrus juices. Citrus fruits and juices were analyzed for physico-chemical properties. The ‘Pamelo’ excelled in terms of average fruit weight (451.83 ± 7.1 g), fruit volume (543.33 ± 9.1 cm3) and rag percentage (68.64 ± 1.1%). ‘Valencia late’ (48.67 ± 0.3%), ‘Flame’ (48.38 ± 1.3%) and ‘Kinnow’ (35.95 ± 4.9%) were good in juice %. The juice was subjected to sonication treatment at 15°C for 5 min keeping pulse duration 5 s on and 5 s off (70% amplitude level and 20 kHz frequency). Total phenol, flavonoids, free radical scavenging activity, antioxidant capacity, and reducing power increased in fruit juices as a result of sonication. The total phenolic contents in the juices of all citrus cultivars ranged from 223.49 ± 4.5 to 590.47 ± 5.5 µg gallic acid equivalent/g and increased from 315.18 ± 6.1 to 645.44 ± 7.1 µg GAE/g after ultrasonic processing. The DPPH values of juices of all citrus cultivars ranged from 791.54 to 1251.93 µmol equivalent of trolox/mL and increased from 1001.54 to 1336.77 µmol equivalent of trolox/mL after applying ultrasound. The sonication is highly feasible for practical use in the industry for the production of citrus fruit juices with improved quality in terms of nutrients.