Microencapsulação de probióticos e extrato bioativo de casca de cebola roxa (Allium cepa L.) por gelificação iônica externa

Abstract

The development of products containing one or more bioactive compounds has become an attractive way to the consumer as a way to establish a better quality of life. Among the bioactive compounds, probiotics and antioxidant compounds stand out, however, their application in food matrices becomes limited as they are extremely sensitive to adverse conditions. Therefore, new alternatives to introduce these compounds to the consumer's daily life are needed. Microencapsulation is a promising, safe and effective technology for the delivery of several bioactive compounds. Among the various microencapsulation techniques, there is the external ionic gelation. The objective of this work was to develop alginate microparticles containing the probiotic Lactobacillus casei LC03 in combination with red onion (Allium cepa L.) peel extract at different concentrations (5, 20 and 40%), using the external ionic gelation technique (Article II), for later application in a food matrix (Article III). Article II evaluated the viability of probiotics under simulated gastrointestinal conditions, during storage at -18, 7 and 25 °C for 90 days and resistance of microparticles to heat treatment (72 °C / 15 sec and 63 °C / 30 min). In addition to the morphology, average diameter and encapsulation efficiency of microparticles. Finally, in Article III, microparticles were added to strawberry pulp, where microbiological and physicochemical analyzes of the pulp, gastrointestinal viability and shelf life of the probiotics in the product were performed, as well as size, morphology and encapsulation efficiency of the microparticles. The microparticles varied in size from 149.29 t to 167.05 μm in Article II and from 136.00 to 305.00 μm in Article III. The encapsulation efficiency of probiotics and compounds present in the extract was satisfactory in both manuscripts. The microparticles were able to protect the probiotics against heat treatment at different temperatures (Article II). In Article II, the microparticles of the treatment containing alginate + 20% extract showed better survival of the probiotic under simulated gastrointestinal conditions, as the different microparticles were applied to the strawberry pulp, the formulations with alginate and alginate + 5% extract demonstrated more satisfactory results (Article III). As for the shelf life of probiotics during storage, in Article II, when evaluating temperatures of 25, 7 and -18 °C, all microparticle formulations remained viable until the end of the experiment (90 days) at -18 °C C, which justifies the choice of frozen strawberry pulp for the application of microparticles. When applied to the pulp (Article III), the treatments containing alginate and alginate + 5% extract reached the longest period of viability (60 days). Thus, the microparticles developed in this study are viable for the development of a new functional and vegan matrix, allowing to increase the diversification of products that contain probiotics.