Influence of In Vitro Digestion on Antioxidant Activity of Enriched Apple Snacks with Grape Juice.

Constanza Pavez-Guajardo,Jorge Moreno,Guido Sáez-Trautmann,Simone Mazzutti,María Estuardo Guerra-Valle,Sandra R S Ferreira

doi:10.3390/foods9111681

Constanza Pavez-Guajardo, Jorge Moreno + Show 4 more

Open Access

https://doi.org/10.3390/foods9111681

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Abstract

Fruits are sources of bioactive compounds (BACs), such as polyphenols. This research aimed to study the in vitro bioaccessibility of polyphenols from enriched apple snacks with grape juice and determine their antioxidant capacity. Impregnation (I) treatments were carried out at atmospheric pressure and in a vacuum (IV) at 30, 40, and 50 °C and their combinations with ohmic heating (OH), I/OH, and IV/OH. Later, samples were dehydrated by forced convection at 40, 50, and 60 °C. Enriched samples were subjected to in vitro digestion. The total polyphenols, monomeric polyphenols, and antioxidant activities were determined from recovered extracts. Results showed that total polyphenols present in higher concentrations in the gastric phase, 271.85 ± 7.64 mg GAE/100 g d.m. Monomeric polyphenols’ behavior during in vitro digestion for the VI/OH 50 °C and dried treatment (60 °C) was descending, mainly in quercetin, which decreased by 49.38% concerning the initial concentration, before digestion. The cyanin, catechin, epicatechin, and epigallocatechin decreased by 26.66%, 20.71%, 23.38%, and 21.73%, respectively. Therefore, based on obtained results, the IV/OH 50 °C treatment (dried 60 °C) is the best combination to incorporate polyphenols from grape juice.

Highlights

To achieve products with health-promoting characteristics, food enrichment strategies, such as vacuum impregnation [1], vacuum ultrasonication [2], ultrasound-assisted, and osmotic impregnation [3], are widely applied
Through the combination of vacuum impregnation (VI) and ohmic heating (OH), an apple snack enriched with grape juice was created
During the in vitro digestion procedure, the highest total polyphenol content was identified in the gastric phase for apple snacks enriched with grape juice

Summary

Introduction

To achieve products with health-promoting characteristics, food enrichment strategies, such as vacuum impregnation [1], vacuum ultrasonication [2], ultrasound-assisted, and osmotic impregnation [3], are widely applied. Another technology used is ohmic heating, which converts electrical into thermal energy, allowing an even and rapid increase, resulting in a more effective process guaranteeing nutrient retention [4]. Antioxidants’ effects depend on their concentrations in fruits and vegetables and their bioaccessibility and bioavailability after ingestion. In vitro digestion allows us to determine those nutrients’ bioaccessibility once the food is ingested [7] In vitro digestion has often been used to simulate gastrointestinal conditions because it can be considered relatively simple when compared to in vivo models in addition to being safe and not presenting ethical restrictions [5].

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