Quality parameters and bioactive compound bioaccessibility changes in probiotics fermented mango juice using ultraviolet-assisted ultrasonic pre-treatment during cold storage

Fermentation processes involve the participation of enzymes and organic catalysts, generated by range of microorganisms to produce chemical transformations. Ultrasound can be used in such processes to either monitor the progress of fermentation or to influence its progress. High frequency ultrasound (>2MHz) has been extensively reported as a tool for the measurement of the changes in chemical composition during fermentation providing real time information on reaction progress. Low frequency ultrasound (20-50kHz) can influence the course of fermentation by improving mass transfer and cell permeability leading to improved process efficiency and production rates. It can also be used to eliminate micro-organisms which might otherwise hinder the process. This review summarises key applications of high and low frequency ultrasound in food fermentation applications.

Strong interest of consumers in acquiring minimally processed foods that conserve the different micronutrients has raised the need to study the effect of food processing methods on quality attributes. The aim of the study was to determine the effect ultrasound treatment on color, and the bioactive compounds (ascorbic acid, total phenols, carotenoids, and provitamin A) of Cape gooseberry juice. Color values, ascorbic acid, total phenols, carotenoids, and Retinol Activity Equivalent (RAE) were measured. The results indicate significant reductions (p<0.001) in the chromaticity, yellowing index (IY), and acid ascorbic content was observed in all the juice samples sonicated. But there were significant increases (p<0.001) in hue, the total color differences (TCD), total phenols, carotenoids, and RAE value as compared to control. The results demonstrated that ultrasound processing increase the availability of carotenoids, total phenols and RAE in Cape gooseberry juice.