Encapsulação de extrato da casca de jabuticaba em fibras de amido de semente de abacate pela técnica de electrospinning: desenvolvimento, caracterização e aplicação

Abstract

Plant extracts rich in anthocyanins can be a good alternative for application in food, due to its antioxidant activity, however, anthocyanins are very unstable pigments and can be degraded during processing. The objective of this work was to encapsulate extract from the bark of jabuticaba using the electrospinning technique and starch obtained from the seed of avocado as wall material, in addition evaluate the application in a food matrix. To the polymeric solutions of avocado seed starch were prepared in concentrations of 10, 20 and 30% in 75% formic acid, and stirred for 24 hours, to ensure complete gelatinization of the starch. After defining the best starch concentration, the jabuticaba extract was incorporated. Extract concentrations of 3, 6 and 9% were tested, in relation to the weight of starch, and the morphology and size of the fibers were evaluated using microscopy scanning electronics; contact angle; infrared spectroscopic profile with Fourier transform; thermogravimetric analysis; encapsulation efficiency; antioxidant activity by capturing DPPH and ABTS radicals; phenolic compounds totals. The fiber with the best characteristics was applied to yogurt, with bioaccessibility studies of phenolic compounds. The extract presented a content of total phenolic compounds and total anthocyanins equal to 1050,16 and 294.53 mg. g-1, respectively, and demonstrated the ability to scavenge free radicals ABTS and DPPH of 93.00 and 53.61%, respectively. The ultrafine fibers presented smooth, continuous and uniform morphology, with average diameters that varied between 328 and 188 nm, with encapsulation efficiency above 50% and thermal resistance up to approximately 300 ºC. The starch fibers of the avocado seed with encapsulated extract exhibited antioxidant activity against free radicals ABTS, DPPH and phenolic compound content between 206 and 260 mgGAE.g-1, increasing with the extract content in the fibers. The bioaccessibility of phenolic compounds significantly increased in the intestinal phase through the encapsulation technique.