engleski

Mathematical modeling of the release of phenolic compounds from encapsulated grape pomace extracts during simulated digestion in vitro

In line with the concept of circular bioeconomy, grape pomace (GP), a solid waste from wineries, has great potential for the production of value- added products with various applications in the pharmaceutical, food, and cosmetic industries. Bioactive phenolic compounds from GP have numerous beneficial effects on human health that depend on their stability, controlled release, and delivery in the digestive system and can be enhanced by encapsulation. Mathematical modeling is an emerging topic and a useful tool to predict the process of release and delivery of active compounds from an encapsulated matrix. The influence of different natural coatings (sodium alginate, and combination of sodium alginate with gelatin, gum Arabic, and chitosan) used for encapsulation of polyphenol-rich GP extract and different drying methods (air-, vacuum-, and freeze-drying) of the encapsulated microbeads (MB) on the release of phenolic compounds during simulated enzyme-free digestion in vitro, was studied. Encapsulation efficiency was calculated from the total phenolic content (TPC) before and after encapsulation. Four mathematical models based on Fick's law of diffusion were tested for predicting the release of phenolic compounds from dry encapsulated microbeads. The adjusted coefficient of determination, model selection criterion, and Akaike information criterion were considered for selection of the most suitable model. The results show that the addition of other coating to the sodium alginate increased the encapsulation efficiency. The highest efficiency was achieved by the addition of gelatin, which was 68.74%, while it was 35.26% for sodium alginate. When comparing the influence of drying methods on the release of phenolic compounds from microbeads, freeze-drying proved to be the best method, as a maximum of 35.47 mgTPC/gMB was released at the end of the intestinal phase for the sodium alginate- chitosan, while vacuum drying and air drying released 31.33 and 27.29 mgTPC/gMB, respectively, for the same sample. The release of phenolic compounds from microbeads followed Fick's law of diffusion. It can also be observed that the microbeads dried in different ways did not behave according to the same model, except for sodium alginate-gelatin, whose release can be described by the Higuchi model for all drying methods, and sodium alginate described by the Korsmeyer-Peppas model.

polyphenol-rich grape pomace extracts ; ionic gelation ; in vitro simulated digestion ; mathematical models

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