Modificação de bentonita por ultrassom-assistido para adsorção de antocianinas de açaí (Euterpe precatoria Mart.)

Abstract

Assisted-ultrasound is one of the most promising technologies for non-thermal processing in food, less energy and water consumption, excellent preservation of nutritional characteristics and sensory profile. In addition to being effective in inactivating enzymes and microorganisms in fruit juices and pulps. The research is based on the analysis of the efficiency of bentonite in the anthocyanin adsorption process. Clays have been applied in industries for adsorption of pigments, pharmaceutical industry as carriers of active ingredients and food as in the bleaching of oils. The objective of this study was to evaluate the inclusion of the clarified açaí juice anthocyanins in Custom Clarifying Clay (ACC) seeking to determine the effect of processing operations (homogenization by magnetic stirring and assisted ultrasound) in different clay concentrations (0–8% in m / m, dry basis). Clay and clay / anthocyanin complexes were characterized by XRF, XRD, UV-VIS, pH Assessment and Total Anthocyanins Content. For the development of the methodology, açaí juice clarification was first used through ultracentrifugation in order to obtain anthocyanins. The mixture of the clarified juice with the ACC was carried out by magnetic stirring and homogenized in an Ultra-Turrax, centrifuged to separate the supernatants from the precipitates, later lyophilized, generating powder complexes containing the anthocyanins. With variation of clay modification by assisted ultrasound. The results obtained were characterized by RXF which made it possible to determine and quantify the elements found in pure clay the following average levels of minerals where the major element is silicon (56.06%), iron (20.48%), aluminum (12, 84%) and others (10.62%). By X-ray diffraction (XRD) where it was possible to observe in the diffractogram the peaks containing phases, such as Mnt, which refers to the crystallographic plane (0 0 1) and quartz, characteristic of sodium bentonites. The basal spacing of Mnt increased due to anthocyanins/clay reason, corroborating the anthocyanins intercalation. The identified compound was cyanidin-3-glycoside through total anthocyanin content. The total soluble solids of the açaí pulp were evaluated and showed me 16.3% ºBrix and the pulp yield was 40%. Thus, this work showed that the complex obtained at 8% clay was the most stable. And it allowed to conclude that the anthocyanins intercalation occurred in the Mnt lamellae, becoming a potential nanocomposite or natural nanopigment.