Encapsulation as a tool to increase the bioaccessibility of phenolic compounds obtained from tropical fruits and their by-products

Renan Danielski
PhD Student
Department of Biochemistry

Date: February 27, 2023
Time: 1:00 p.m. to 2:00 p.m. 
Room: CSF 1302

Selected tropical fruits (e.g., jerivá and butiá) are undervalued and not currently produced in a large-scale. This is partly due to lack of knowledge about their nutritional potential and bioactive composition. Meanwhile, processing of highly-commercialized fruits, such as guava, generates a high amount of by-products (e.g., seeds, peels, pulp leftover) that can also serve as a rich source of bioactives. However, evidence indicate that some bioactive classes found in these fruits (e.g., phenolic compounds) show poor intestinal absorption due to their low bioaccessibility. Encapsulation may be used to protect the integrity of phenolics and their bioactivities throughout the gastrointestinal (GI) tract passage, while also promoting their controlled release. Therefore, phenolic extracts from guava, butiá, jerivá, and their by-products were encapsulated by freeze-drying using maltodextrin as a wall material. Encapsulated and nonencapsulated extracts were then subjected to in vitro simulated GI digestion consisting of oral, gastric, small intestine, and large intestine phases. The digested extracts were analyzed for their total phenolic (TPC) and total flavonoid (TFC) contents, antiradical activity against DPPH and ABTS radicals, ferric reducing antioxidant power (FRAP), a-glucosidase and pancreatic lipase inhibition, LDL-cholesterol peroxidation inhibition, and hydroxyl radical-induced supercoiled DNA strand scission inhibition. Encapsulation efficiency was moderate to high (65-89%) amongst samples. Phenolic content was significantly increased in the bioaccessible fraction of encapsulated extracts (3.4 – 15.0 mg of gallic acid equivalent (GAE)/g) when compared with the nonencapsulated ones (0.02 - 1.5 mg GAE/g), which was also observed for the antioxidant activity. High levels of a-glucosidase inhibition (84-90%) were recorded for the encapsulated extracts upon small intestine digestion. Several encapsulated samples exhibited an enhancement of their oxidative protection toward LDL and DNA after small intestine digestion. Therefore, encapsulation was shown as a promising tool for retaining the bioactivities related to the health-promoting benefits of polyphenols. Moreover, encapsulated phenolic extracts from tropical fruits show great potential for use as ingredients in functional foods, pending in vivo confirmation.