Impact of power ultrasound on chemical and physicochemical quality indicators of strawberries dried by convection

Abstract

A study on the quality parameters of strawberries dehydrated by convection assisted by power ultrasound (US) at 40-70°C and 30 and 60W has been carried out for the first time. In general, the quality of US-treated samples was higher than that of commercial samples. Even under the most severe conditions used (US at 70°C and 60W), high values of vitamin C retention (>65%) and scarce advance of Maillard reaction (2-furoylmethyl derivatives of Lys and Arg<90mg 100g(-1) protein) were observed. Rehydration ratio was not affected by the power applied and the obtained values were similar to those of convectively-treated samples. According to the results here presented, US is a suitable example of an emerging and environmentally friendly technology that accelerates convective drying, allowing the obtainment of dried strawberries with premium quality.

Keywords: Convective dehydration; Maillard reaction; Quality parameters; Strawberry; Ultrasound; Vitamin C.