A Polyphenolic Extract from Olive Mill Wastewaters Encapsulated in Whey Protein and Maltodextrin Exerts Antioxidant Activity in Endothelial Cells.

Efthalia Kerasioti,Dimitrios Stagos,Demetrios Kouretas,Christos Mantas,Paschalis Gkoutsidis,Aristidis S Veskoukis,Konstantinos Petrotos,Konstantina Kreatsouli,Dimitrios Ladas,Konstantinos Zampakas,Zinovia Fousteri

doi:10.3390/antiox8080280

Efthalia Kerasioti, Dimitrios Stagos + Show 9 more

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https://doi.org/10.3390/antiox8080280

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Abstract

The aim of the present study was to compare maltodextrin and whey protein as encapsulation carriers for olive mill wastewater (OMWW) phenolic extract for producing antioxidant powder, by using spray drying under 17 different conditions. In some samples, gelatin was also added in the encapsulation mixture. The antioxidant activity was assessed in vitro by using the DPPH•, ABTS•+, reducing power and DNA plasmid strand breakage assays. The results showed that both materials were equally effective for producing antioxidant powder, although by using different conditions. For example, inlet/outlet temperature of the spray drying did not seem to affect the maltodextrin samples’ antioxidant activity, but whey protein samples showed better antioxidant activity at lower temperatures. Gelatin use decreased antioxidant activity, especially in whey protein samples. The two most potent samples, one encapsulated in maltodextrin and the other in whey protein, were examined for their antioxidant effects in human endothelial cells by assessing glutathione (GSH) and reactive oxygen species (ROS) levels. Both samples significantly enhanced the antioxidant molecule of GSH, while maltodextrin sample also decreased ROS. The present findings suggested both materials for encapsulation of OMWW extract for producing antioxidant powder which may be used in food products, especially for the protection from ROS-induced endothelium pathologies.

Highlights

Olive mill wastewaters (OMWWs) are byproducts of the olive oil production process, causing significant problems such as soil contamination and eutrophication, when they are discarded in the environment
17 powders produced by encapsulation of an OMWW polyphenolic extract by spray drying under different conditions in whey protein, maltodextrin, and gelatin were tested for their free-radical scavenging activity against DPPH and ABTS+ radicals
Maltodextrin and whey protein have been used for the encapsulation of OMWW polyphenolic extracts [21,22,23,24]

Summary

Introduction

Olive mill wastewaters (OMWWs) are byproducts of the olive oil production process, causing significant problems such as soil contamination and eutrophication, when they are discarded in the environment. OMWWs have been extensively considered as a byproduct, several studies have shown that they are rich in polyphenolic compounds (e.g., oleuropein, tyrosol, hydroxytyrosol, coumaric acid, caffeic acid, vanillic acid, ferulic acid, kaempferol, and quercetin) with important biological activities [1]. Our research group has previously demonstrated that administration of feed supplemented with polyphenols from OMWW improves the redox status in farm animals [3,4,5]. Polyphenolic extracts from OMWW may be used as food supplements or preservatives, but their unpleasant bitter taste is a significant problem. The encapsulation of polyphenolic extracts is an effective way to preserve their stability and bioactivity, Antioxidants 2019, 8, 280; doi:10.3390/antiox8080280 www.mdpi.com/journal/antioxidants

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