Efeito sinergístico da termossonicação na estabilidade dos compostos bioativos e atividade antioxidante em suco de amora

Abstract

Thermosonication, a combination of ultrasound with mild temperatures, is a promising technique for food preservation due to its proven potential in providing an increase in the rate of enzymatic and microbiological inactivation compared to traditional heat treatment, which can considerably minimize product exposure to heat. heat and undesirable nutritional losses. However, studies that investigate the effect of thermosonication on the nutritional stability of foods are still inconclusive. In this context, the aim of the present study was to evaluate the synergistic effect of ultrasound with temperature (thermosonication) on the stability of bioactive compounds and antioxidant activity in blackberry juice. The experiment was conducted based on the Central Composite Rotational (DCCR) design, varying the factors, temperature and time. The samples were submitted to conventional heat treatment, with the binomials of time X temperature defined by the design. To evaluate the effect of the combination of ultrasound and heat, the samples were subjected to thermosonication. After the treatments, the total content of phenolic compounds, anthocyanins, as well as the antioxidant activity was determined by the method of ABTS, DPPH and β-carotene system. The results were submitted to principal component analysis and to estimate the synergistic effect of thermosonication the samples were submitted to the t-student mean test between treatments. As a result, thermosonication processing (60%) contributed to minimize the degradation of antioxidant activity (ABTS and β-carotene) in blackberry juice. The best results for anthocyanins and total phenolic compounds were obtained in thermosonicated juices at 60% amplitude, in the binomial of 75 ºC for 30s. This treatment condition can be considered the best result as it provides the lowest degradation in the content of total phenolic compounds and anthocyanins in the blackberry juice. Thus, thermosonication can be an alternative to traditional conservation methods, however, the potential effects of this technique are highly dependent on the time, temperature and amplitude factors applied to the blackberry juice, which must be investigated to establish the ideal and particular conditions for conservation.