Antioxidant properties of processed cheese spread after freeze-dried and oven-dried grape skin powder addition

Michaela Frühbauerová,František Buňka,Tomáš Hájek,Richardos Nikolaos Salek,Libor Červenka,Helena Velichová

doi:10.5219/1310

Abstract

Processed cheese spread (PCS) is a popular product with high nutritional value and containing protein, fat and minerals. Grape skin is waste from winery processing plants that still has phenolic substances with significant antioxidant activity that could be used for valorisation of processed cheese and increasing the content of nutrients, phenolics and overall antioxidant properties. Both oven-dried (OD) and freeze-dried (FD) grape skin (GS) powder was characterised by the principal ingredients, the content of phenolic compounds and antioxidant capacity. Similarly, the influence of the addition of OD-GS and FD-GS powders on processed cheese spread (PCS) at 1% and 2% (w/w) levels were examined. The OD-GS and FD-GS powders were characterised by protein content, fat content, moisture and dietary fibre, thus showing that drying technique did not affect those parameters. The OD-GS powder exhibited higher content of rutin, (+)-catechin, (-)-epicatechin and total flavonoid content (TFC), while higher total phenolic content (TPC) and ABTS radical cation were observed for freeze-dried GS powder. Fortification of PCS with 1% and 2% (w/w) of GS powder increased protein content. An ANOVA procedure revealed that addition of FD-GS powder to processed cheese spread was superior to TPC values together with rutin, (+)-catechin, and (-)-epicatechin contents. The higher phenolic contents reflected the higher antioxidant capacity of PCS samples fortified with FD-GS powder. Freeze-dried gape skin powder was the better choice for valorisation of processed cheese spread.

Highlights

Processed cheese spread (PCS) is a multi-component mixture made from water, cheese, fat, and emulsifying salts
Freeze-dried grape skin (GS) powder has a higher level of total phenolic content (TPC) (19.97 ±1.60 mg GAE.g-1 Dry matter (DM)) and more than twice as high TEACABTS value (127.10 ±27.28 mg Trolox.g-1 DM) in comparison with the oven-dried GS samples
From eight selected polyphenolic compounds, only the presences of (+)-catechin, (-)-epicatechin and rutin were confirmed in grape skin powder samples using retention time and absorption spectra in the current study

Summary

Introduction

Processed cheese spread (PCS) is a multi-component mixture made from water, cheese, fat, and emulsifying salts (phosphates or citrates). This mix is processed by stirring and melting in temperatures ranging from 85 to 110 °C for up to 20 min (Černíková, et al, 2018). Processed cheeses are products with extended shelf life that deliver bioactive proteins, fats, minerals and vitamins to consumers (Henning, et al, 2006). Despite the high nutritional value, various types of cheese have been enriched by addition of herb or medicinal plant extracts during their preparation, for instance, the addition of rosemary leaves to ripened semi-hard cheese (Marinho, et al, 2015). The authors found that hard low-fat cheese fortified by catechin maintained its antioxidant activity after in vitro digestion experiment

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