Development of microparticles containing pitanga (Eugenia uniflora) and mate tea (Ilex paraguariensis) bioactives by the ionic gelation technique: evaluation of stability and application in food matrices

Abstract

Pitanga extract (Eugenia uniflora) has been attracting attention from the food and pharmaceutical industries for the health benefits (anti-inflammatory, antifungal, antidiarrheal, hypoglycemic and antihypertensive effects) and as a natural source of dyes, with strong antioxidant activity and high content of anthocyanins (delphinidin-O-glucoside and cyanidin-3-O-glucoside). Mate tea (Ilex paraguariensis) is known for the high content of polyphenols that may be related to hypocholesterolemia and hepatoprotective functions, central nervous system stimulation and its diuretic properties. Consumers are better aware of the effects of these and various other natural substances in their body and have been looking for alternatives to consume them, such as processed foods containing these substances. This demand creates a challenge for the food industry to be able to add these substances (often sensitive to industrial processing conditions) to their products and keep them "functional" after processing and to last the storage. Microencapsulation is a way of guaranteeing bioactive compounds greater stability to adverse conditions of processing and storage, besides the possibility of release of content in a controlled way and under specific conditions. Encapsulation by ionic gelation occurs by the electrostatic interaction between opposite charges of a polymer and an electrolyte that, when ionically bonded, form a stable complex that retains the compound of interest (active) in the formed matrix. Its main advantages are the mild process conditions and the possibility of enteric release of the substances of interest. In this context, the objective of this work is to employ ionic gelation as a method of microencapsulation of pitanga and mate tea extracts, using as wall material the anionic polymer pectin (amidated or conventional), evaluating the best concentration and mechanical characteristics for dripping technique (Encapsulator Büchi B-390).The two microparticles will be evaluated for the most relevant process and physical and chemical characteristics. Under the best process conditions they will undergo fluid bed drying and the stability of the encapsulated bioactives, the application in food matrix and the stability during the shelf life of the food will be investigated. In addition to the expected technical results, the project reinforces the line of research in microencapsulation in ITAL as well as the partnership with the School of Food Engineering of Unicamp, with the possibility of providing innovative technology for the national food ingredients sector. (AU)