Sonication improves kasturi lime (Citrus microcarpa) juice quality

Freshly squeezed kasturi lime fruit juice was sonicated (for 0, 30 and 60 min at 20 degrees C, 25 kHz frequency) to evaluate its impact on selected physico-chemical and antioxidant properties, such as pH, degrees Brix, titratable acidity, Hunter color values (L*, a*, b*), ascorbic acid, DPPH radical scavenging activity, total phenolics, antioxidant capacity, flavonoids and flavonols. Additionally, the effect of sonication treatments on the microbial load (TPC, yeast and mold) were also evaluated. Sonication of juice samples for 60 min showed enhancement in most of the bioactive compounds compared to samples treated for 30 min and control samples (untreated). Significant reductions in the microbial load corresponding to sonication time were also recorded. Results of the present study indicate that sonication may be employed as a suitable technique for kasturi lime juice processing, where antioxidant and other bioactive compound retention or enhancement is desired, along with the achievement of safety and quality standards. (C) 2011 Elsevier B.V. All rights reserved.