Fresh grapefruit juice samples were subjected to ultrasound treatment at various treatment times (30, 60 and 90 min) in a bath type sonicator at a frequency of 28 KHz, radiating power of 70% (420 W) and 20 oC. Grapefruit juice samples were stored in sterilized polypropylene tubes at 4±1 oC for a period of 28 days. This study was initiated with the objective of calculating the effect of ultrasound treatment and storage time on acidity, pH, ºBrix, electrical conductivity (EC), hunter color values (L*, a* and b*), non-enzymatic browning (NEB), cloud value (CV) and bioactive compounds of grapefruit juice. Results showed that there was no change in pH, ºBrix and acidity, while a significant decrease in all the color values (L*, a* and b*) and significant increase in EC, cloud value, total antioxidant capacity (TAC), DPPH free radical scavenging activity, total phenolics (TP), total flavonoids (TF) and total flavonols was observed in all the juice samples sonicated for 30, 60 and 90 min as compared to control. During storage, NEB and hunter color values (L*, a* and b*) were increased, while CV, DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity, TAC, TP, TF and total flavonols were decreased significantly in all the ultrasound treatments, but more stability was determined in sonication treatment of 90 min as compared to control during storage period of 28 days. The findings of this study suggested that sonication for 90 min may be employed successfully in the processing of grapefruit juice at industrial scale.

Author Name: Rana Muhammad Aadil, Xin-An Zenga, Arshad Mehmood Abbasi, Muhammad Saeed Khan, Saud Khalid, Saqib Jabbar, Muhammad Abid

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Keywords: Ultrasound processing; grapefruit juice; storage; cloud value; polyphenols; antioxidant capacity.

ISSN: 2311-3219

EISSN: 2311-3219

EOI/DOI:

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