No abstract

The present work evaluated the influence of different thermosonication conditions on the quality improvement of elephant apple (Dillenia indica) juice. The juice was processed under thermosonication at different temperatures (30–50°C) for different time periods (15–60 min). The results of sonication treatments were compared with fresh and thermally treated juices. The objectives of the research work were to determine the effect of thermosonication on the quality attributes such as pH, titratable acidity (TA), total soluble solids (TSS), total phenolic contents (TPC), total flavonoid contents (TFC), antioxidant activity (AA), ascorbic acid levels, microbiological, and sensory properties. pH, TA, and TSS of thermosonicated and pasteurized juice samples did not produce any significant (p < .05) differences. From the experimental results, it was also seen that thermosonication has improved the quality of elephant apple juice by increasing the levels of TPC, TFC, and AA significantly (p < .05) and ensuring the microbial safety of juices. Furthermore, the findings of the present study indicated that the thermosonication can be employed for processing of elephant apple juice as a replacement method for thermal processing with enhanced quality.Practical applicationsUltrasound processing is one of the new method which has been applied widely to improve the shelf life of fruit juices without altering the quality attributes of juices. Commonly, thermal processing technologies are applied to improve the keeping quality of fruit juices, but it has some detrimental effects on the final quality of fruit products. So, ultrasound processing can be utilized as an alternative method to thermal processing. In the present work, ultrasound processing was applied to enhance the quality of elephant apple juices.

In recent years, thermosonication (TS) has been considered as a substitute to conventional heat treatments as it improves the quality characteristics of fruit juices. In the present research work, the impact of pasteurization (90 ± 2 C for 1 min) and TS on the quality of tangor fruit juice was examined and findings of the work were compared with freshly prepared juice. The quality characteristics, such as bioactive compounds, microbial counts and physicochemical properties were checked for all samples. After TS, the levels of total phenolic content (TPC) (683.25-747.84 μg gallic acid equivalents [GAE0/ml]), total flavonoid content (TFC) (61.76-71.51 μg quercetin equivalents [QE]/ml) and anti-oxidant activity (AOA) (73.27-83.63%) of tangor juices were improved as compared to fresh (TPC À 584.84 μg GAE/ml, TFC À 34.65 μg QE/ml and AOA À 49.71%) and pasteurized juices (TPC -471.74 μg GAE/ml, TFC -26.64 μg QE/ml and AOA -38.19%). But, a slight decrement in ascorbic acid content was perceived in thermosonicated juices (24.48-27.26 mg/100 ml) as compared to fresh tangor juice (45.55 mg/100 ml) but higher than pasteurized juice (22.55 mg/100 ml). TS also reduced the microbial populations in tangor juices with minor changes in the physicochemical properties as compared to fresh juices. Therefore, TS may be used effectively for the treatment of tangor juices to produce a product with better levels of bioactive compounds.