Extração, purificação e aplicação de compostos fenólicos a partir de folhas de olerícolas orgânicas utilizando resinas macroporosas de adsorção

Abstract

In the last decades, the consumers demand for food with good technological and sensory characteristics and functional properties has increased, due to the search for healthier food. This behavior culminates with a higher consumption of plant food and impacts on the fast development of food processing industries, which increase the wastes and food by-products production. On the other hand, the consumption of non-conventional food and by-products has been studied in the last years. Leaves of vegetable oleraceous present high nutritional value and higher nutrients contents (fibers and phenolic compounds) and antioxidant activity when compared to another parts of the plant. In general, In general, organic vegetables present higher contents of phenolic compounds when compared to conventional ones, because the production of secondary metabolites in organic plants is more expressive. There is a global demand for the use of environmentally sustainable separation techniques, such as microporous adsorption resins, which allows effective separation and good recovery of phytochemicals of interest, as phenolic compounds. However, studies involving the extraction of antioxidant extracts from leaves and their potential use by the food industry are still very incipient. Therefore, the objective of this work is to extract and purify phenolic compounds from leaves of different organic olive groves (sweet potatoes, cassava and arrowroot), using macroporous resins adsorption as a "green separation" technique, with a view to application in food products. It was observed that the organic purple-fleshed sweet potato leaves were the evaluated material that presented more promising results in relation to high antioxidant capacity and content of phenolic compounds. Among the macroporous resins tested, XAD 16 and XAD 7HP presented a better recovery of phenolics from leaves of purple-fleshed sweet potatoes, being related to higher adsorption and desorption capacity. However, XAD 7 HP presented higher efficiency because it provided less time of adsorption process. The results obtained in the adsorption and kinetic desorption assays showed that the flow rates of 3 mL / min and 7 mL / min were chosen for dynamic adsorption and desorption, respectively. This study demonstrated that the addition of phenolic extracts from leaves of purple-fleshed sweet potatoes obtained by separation with macroporous resins was able to provide greater oxidative stability of soybean oils. The high antioxidant capacity of the purified extracts indicated that purification and separation with macroporous resins may be an efficient technique in the development of added food products of compounds of interest obtained from vegetable by-products.