In Vitro Bioaccessibility Assessment of Phenolic Compounds from Encapsulated Grape Pomace Extract by Ionic Gelation

Abstract

Grape pomace is a by-product of winemaking characterized by a rich chemical composition from which phenolics stand out. Phenolics are health-promoting agents, and their beneficial effects depend on their bioaccessibility, which is influenced by gastrointestinal digestion. The effect of encapsulating phenol-rich grape pomace extract (PRE) with sodium alginate (SA), a mixture of SA with gelatin (SA-GEL), and SA with chitosan (SA-CHIT) on the bioaccessibility index (BI) of phenolics during simulated digestion in vitro was studied. A total of 27 individual phenolic compounds (IPCs) were quantified by UHPLC. The addition of a second coating to SA improved the encapsulation efficiency (EE), and the highest EE was obtained for SA-CHIT microbeads (56.25%). Encapsulation affected the physicochemical properties (size, shape and texture, morphology, crystallinity) of the produced microbeads, which influenced the delivery of phenolics to the intestine and their BI. Thus, SA-GEL microbeads had the largest size parameters, as confirmed by scanning electron microscopy (SEM), and the highest BI for total phenolic compounds and IPCs (gallic acid, 3,4-dihydroxybenzoic acid and o-coumaric acid, epicatechin, and gallocatechin gallate) ranged from 96.20 to 1011.3%. The results suggest that encapsulated PRE has great potential to be used as a functional ingredient in products for oral administration.

Microencapsulation of Grape Pomace Extracts with Alginate-Based Coatings by Freeze-Drying: Release Kinetics and In Vitro Bioaccessibility Assessment of Phenolic Compounds

“…In order to determine the statistical significance of the differences between the arithmetic means of the samples, a one-way analysis of variance (ANOVA) was performed using TIBCO Statistica software. After determining significant differences, a subsequent post-hoc analysis was performed using Duncan's multiple range test to determine the specific sample groups that showed significant differences (p < 0.05) [68]. In the figures samples from identical populations are identified by uniform alphabetical letters.…”

“…According to the INFOGEST protocol [54], in vitro enzyme-free release and simulated digestion of extracts (CSE, CFE, ME) and freeze-dried powders was performed, with some modifications described by Martinović et al [40] and Martinović et al [68]. The protocol consists of three phases: oral (OP), gastric (GP), and intestinal (IP).…”

“…4.9.2. Simulated Digestion In Vitro and Bioaccessibility Index (BI) Simulated digestion in vitro was performed according to the modified INFOGEST protocol described by Martinović et al [68] using test tubes, each of which presented a specific time interval of each phase (OP3, GP63, GP123, IP163 and IP243). These test tubes were placed on a vertical multifunction rotator (PTR-60, Grant-bio Instruments, UK) in a thermostat (TC 135 S, Lovibond, Dortmund, Germany) heated at 37 °C.…”

The Effects of Drying and Grinding on the Extraction Efficiency of Polyphenols from Grape Skin: Process Optimization

“…Phenolic compounds are abundant and diverse natural products found in plants, exhibiting a wide range of physiological properties, including anti-allergic, anti-inflammatory, antimicrobial, antioxidant, cardioprotective, and vasodilating effects [20]. Many phenolic compounds have been identified in grape pomace, with anthocyanins, hydroxybenzoic and hydroxycinnamic acids, flavan-3-ols, flavonols, and stilbenes being the most prevalent [21,22].…”

Effect of Fungal Solid-State Fermentation on the Profile of Phenolic Compounds and on the Nutritional Properties of Grape Pomace

“…However, not all phenolic compounds from grapes are extracted into the wine during production, leaving about 70% of these bioactive compounds in GP [3]. In order to utilize the bioactive compounds and their benefits, many researchers deal with finding alternative uses of GP, such as obtaining extracts with antioxidant properties, composting and use as biomass for energy production, use in the sustainable production of food enriched with polyphenols and fiber, use in encapsulation techniques, use as fermentation substrates and feed for ruminants [6,[10][11][12][13][14].…”