Spray-Drying Microencapsulation of Grape Pomace Extracts with Alginate-Based Coatings and Bioaccessibility of Phenolic Compounds

Spray-drying is a common technique for the microencapsulation of bioactive compounds, which is crucial for improving their stability and bioavailability. In this study, the encapsulation efficiency (<i>EE</i>), physicochemical properties and in vitro bioaccessibility of phenolic compound...

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Main Authors: Josipa Martinović, Rita Ambrus, Mirela Planinić, Gabriela Perković, Gordana Šelo, Ana-Marija Klarić, Ana Bucić-Kojić
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Gels
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Online Access:https://www.mdpi.com/2310-2861/11/2/130
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author Josipa Martinović
Rita Ambrus
Mirela Planinić
Gabriela Perković
Gordana Šelo
Ana-Marija Klarić
Ana Bucić-Kojić
author_facet Josipa Martinović
Rita Ambrus
Mirela Planinić
Gabriela Perković
Gordana Šelo
Ana-Marija Klarić
Ana Bucić-Kojić
author_sort Josipa Martinović
collection DOAJ
description Spray-drying is a common technique for the microencapsulation of bioactive compounds, which is crucial for improving their stability and bioavailability. In this study, the encapsulation efficiency (<i>EE</i>), physicochemical properties and in vitro bioaccessibility of phenolic compounds from spray-dried encapsulated phenol-rich extracts of grape pomace, a winery waste, were evaluated. Sodium alginate alone (SA) or in a mixture with gum Arabic (SA-GA) or gelatin (SA-GEL) was used as a coating. SA-GEL achieved the highest <i>EE</i> (95.90–98.01%) and outperformed the intestinal release of phenolics by achieving a bioaccessibility index (<i>BI</i>) for total phenolic compounds of 37.8–96.2%. The release mechanism of phenolics from the microcapsules adhered to Fickian diffusion. Encapsulation significantly improved the <i>BI</i> of individual phenolics, with the highest <i>BI</i> values for gallocatechin gallate (2028.7%), epicatechin gallate (476.4%) and <i>o</i>-coumaric acid (464.2%) obtained from the SA-GEL microcapsules. Structural analysis confirmed amorphous matrices in all systems, which improved solubility and stability. These results suggest that encapsulation by spray-drying effectively protects phenolics during digestion and ensures efficient release in the intestine, which improves bioaccessibility. This study contributes to the understanding of biopolymer-based encapsulation systems, but also to the valorisation of grape pomace as a high-value functional ingredient in sustainable food processing.
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spelling doaj-art-4535a0beb9ee4049984fbd3cf8175fb32025-08-20T03:12:05ZengMDPI AGGels2310-28612025-02-0111213010.3390/gels11020130Spray-Drying Microencapsulation of Grape Pomace Extracts with Alginate-Based Coatings and Bioaccessibility of Phenolic CompoundsJosipa Martinović0Rita Ambrus1Mirela Planinić2Gabriela Perković3Gordana Šelo4Ana-Marija Klarić5Ana Bucić-Kojić6Faculty of Food Technology Osijek, Josip Juraj Strossmayer University of Osijek, F. Kuhača 18, HR-31000 Osijek, CroatiaFaculty of Pharmacy, Institute of Pharmaceutical Technology and Regulatory Affairs, University of Szeged, H-6720 Szeged, HungaryFaculty of Food Technology Osijek, Josip Juraj Strossmayer University of Osijek, F. Kuhača 18, HR-31000 Osijek, CroatiaFaculty of Food Technology Osijek, Josip Juraj Strossmayer University of Osijek, F. Kuhača 18, HR-31000 Osijek, CroatiaFaculty of Food Technology Osijek, Josip Juraj Strossmayer University of Osijek, F. Kuhača 18, HR-31000 Osijek, CroatiaFaculty of Food Technology Osijek, Josip Juraj Strossmayer University of Osijek, F. Kuhača 18, HR-31000 Osijek, CroatiaFaculty of Food Technology Osijek, Josip Juraj Strossmayer University of Osijek, F. Kuhača 18, HR-31000 Osijek, CroatiaSpray-drying is a common technique for the microencapsulation of bioactive compounds, which is crucial for improving their stability and bioavailability. In this study, the encapsulation efficiency (<i>EE</i>), physicochemical properties and in vitro bioaccessibility of phenolic compounds from spray-dried encapsulated phenol-rich extracts of grape pomace, a winery waste, were evaluated. Sodium alginate alone (SA) or in a mixture with gum Arabic (SA-GA) or gelatin (SA-GEL) was used as a coating. SA-GEL achieved the highest <i>EE</i> (95.90–98.01%) and outperformed the intestinal release of phenolics by achieving a bioaccessibility index (<i>BI</i>) for total phenolic compounds of 37.8–96.2%. The release mechanism of phenolics from the microcapsules adhered to Fickian diffusion. Encapsulation significantly improved the <i>BI</i> of individual phenolics, with the highest <i>BI</i> values for gallocatechin gallate (2028.7%), epicatechin gallate (476.4%) and <i>o</i>-coumaric acid (464.2%) obtained from the SA-GEL microcapsules. Structural analysis confirmed amorphous matrices in all systems, which improved solubility and stability. These results suggest that encapsulation by spray-drying effectively protects phenolics during digestion and ensures efficient release in the intestine, which improves bioaccessibility. This study contributes to the understanding of biopolymer-based encapsulation systems, but also to the valorisation of grape pomace as a high-value functional ingredient in sustainable food processing.https://www.mdpi.com/2310-2861/11/2/130grape pomacephenolic compoundsencapsulationspray-dryingbioaccessibility
spellingShingle Josipa Martinović
Rita Ambrus
Mirela Planinić
Gabriela Perković
Gordana Šelo
Ana-Marija Klarić
Ana Bucić-Kojić
Spray-Drying Microencapsulation of Grape Pomace Extracts with Alginate-Based Coatings and Bioaccessibility of Phenolic Compounds
Gels
grape pomace
phenolic compounds
encapsulation
spray-drying
bioaccessibility
title Spray-Drying Microencapsulation of Grape Pomace Extracts with Alginate-Based Coatings and Bioaccessibility of Phenolic Compounds
title_full Spray-Drying Microencapsulation of Grape Pomace Extracts with Alginate-Based Coatings and Bioaccessibility of Phenolic Compounds
title_fullStr Spray-Drying Microencapsulation of Grape Pomace Extracts with Alginate-Based Coatings and Bioaccessibility of Phenolic Compounds
title_full_unstemmed Spray-Drying Microencapsulation of Grape Pomace Extracts with Alginate-Based Coatings and Bioaccessibility of Phenolic Compounds
title_short Spray-Drying Microencapsulation of Grape Pomace Extracts with Alginate-Based Coatings and Bioaccessibility of Phenolic Compounds
title_sort spray drying microencapsulation of grape pomace extracts with alginate based coatings and bioaccessibility of phenolic compounds
topic grape pomace
phenolic compounds
encapsulation
spray-drying
bioaccessibility
url https://www.mdpi.com/2310-2861/11/2/130
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