The intensification of processes is essential for the sustainability of the biorefinery concept. Enzyme catalysis assisted by ultrasound (US) may offer interesting opportunities in the agri-food sector because the cavitation effect provided by this technology has been shown to improve the efficiency of the biocatalysts. This review presents the recent advances in this field, focused on three main applications: ultrasound-assisted enzymatic extractions (UAEE), US hydrolysis reactions, and synthesis reactions assisted by US for the manufacturing of agri-food produce and ingredients, enabling the upgrading of agro-industrial waste. Some theoretical and experimental aspects of US that must be considered are also reviewed. Ultrasonic intensity (UI) is the main parameter affecting the catalytic activity of enzymes, but a lack of standardization for its quantification makes it unsuitable to properly compare results. Applications of enzyme catalysis assisted by US in agri-foods have been mostly concentrated in UAEE of bioactive compounds. In second place, US hydrolysis reactions have been applied for juice and beverage manufacturing, with some interesting applications for producing bioactive peptides. In last place, a few efforts have been performed regarding synthesis reactions, mainly through trans and esterification to produce structured lipids and sugar esters, while incipient applications for the synthesis of oligosaccharides show promising results. In most cases, US has improved the reaction yield, but much information is lacking on how different sonication conditions affect kinetic parameters. Future research should be performed under a multidisciplinary approach for better comprehension of a very complex phenomenon that occurs in very short time periods.
Demand for minimally processed fruits have increased due to their nutritional value and an increasing change in consumption habits. Physicochemical, microbiological, structural and sensory changes were determined in minimally processed mangoes (MPM) with chitosan (CH) edible coatings and lemon and orange essential oils (EOL). The MPM was first dipped in citric acid and a texturizing solution and then dipped in CH and lemon or orange EOL coatings. Weight loss, sensory acceptance, total soluble solids, total acidity, ascorbic acid, color changes, firmness and elasticity, and microbiological changes were quantified for 11 days of refrigerated storage. The CH and lemon EOL coating had more acceptance than the other treatments. No differences were found (p>0.05) for weight loss, total acidity, ascorbic acid, firmness or elasticity. There was a high amount of total phenols due to the EOL composition, as well as a high antioxidant capacity in the early days of storage. This characteristic decreased in the final days of the study. There was a decrease in the microbial charge for the lemon EOL treatment, as compared to the other samples. The CH and lemon EOL coating helped to maintain the shelf-life of the MPM for 11 days of storage without affecting the sensory acceptance. The CH and Orange EOL coating did not have an effect on the MPM physicochemical attributes; however, the sensory acceptance was negatively affected with off-flavors conferred to the MPM.