Novel Edible Coating with Antioxidant and Antimicrobial Activities Based on Whey Protein Isolate Nanofibrils and Carvacrol and Its Application on Fresh-Cut Cheese

Qiannan Wang,Bin Jiang,Zhibiao Feng,Dongmei Li,Bo Tian,Chunhong Liu,Hongliang Yu,Jing Xu

doi:10.3390/coatings9090583

Qiannan Wang, Bin Jiang + Show 6 more

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https://doi.org/10.3390/coatings9090583

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Journal: Coatings	Publication Date: Sep 16, 2019
Citations: 41	License type: CC BY 4.0

Affiliation: Northeast Agricultural University

Abstract

The composition and properties of edible coatings (ECs) will significantly influence their effects of food preservation. For the first time, whey protein isolates nanofibers (WPNFs), as a novel material with high hydrophobicity and antioxidant activity, combined with carvacrol (CA) as an antimicrobial agent and glycerol (Gly) as a plasticizer, was used to prepare edible coating (WPNFs-CA/Gly) for preserving fresh-cut Cheddar cheese. The prepared WPNFs and ECs emulsions have been investigated with transmission electron microscopy. Furthermore, the antioxidant activity of ECs emulsions, antimicrobial activity of edible films, and the physical properties of edible films, such as micromorphology, thickness, transparency, and moisture content, have also been evaluated. The weight losses and physical characteristics of both coated and uncoated fresh-cut Cheddar cheese samples have been assessed during storage. The DPPH free radical scavenging rate of WPNFs-CA/Gly emulsion was up to 67.89% and the reducing power was 0.821, which was higher than that of WPI-CA/Gly emulsions. The antimicrobial activity of WPNFs-CA/Gly films was nearly 2.0-fold higher than that of WPNFs/Gly films for the presence of CA. The WPNFs-CA/Gly films had smooth and continuous surfaces, and the transparency reached 49.7% and the moisture content was 26.0%, which was better than that of WPI-CA/Gly films. Furthermore, Cheddar cheese with WPNFs-CA/Gly coatings has shown lower weight losses (15.23%) and better textural properties than those uncoated samples. This in-depth study has provided a valuable and noteworthy approach about the novel edible coating material.

Highlights

Various types of food proteins can be assembled into nanofibers (NFs) under mildly denaturing conditions, such as β-lactoglobulin (β-lg) [1], whey protein isolates [2], ovalbumin [3], soy proteins [4], and pea protein [5]
whey protein isolates nanofibers (WPNFs) could be self-assembled by 5% Whey protein isolates (WPI) at 80 ◦ C incubation for 10 h with constantly 220 rpm magnetic stirring
WPNFs and CA were stable enough to act as edible coatings (ECs) of Cheddar cheese slices

Summary

Introduction

Various types of food proteins can be assembled into nanofibers (NFs) under mildly denaturing conditions, such as β-lactoglobulin (β-lg) [1], whey protein isolates [2], ovalbumin [3], soy proteins [4], and pea protein [5]. Whey protein isolates (WPI), as a traditional industrial product [6], can be used as raw material for preparing whey protein isolates nanofibers (WPNFs) without any pretreatment. WPNFs have improved techno-functional properties, including better foaming and emulsifying properties, self-supporting gelling ability, and increasing viscosity [7,8]. WPI has been more and more frequently used as raw material for preparing NFs. Widely utilized as efficient. The structures (such as fibril morphology, fibril length, and fibril flexibility) as well as functional properties of NFs can be influenced by many factors including raw materials, self-assembly processes, and post-fibrillation processes [10]. High aspect ratios of NFs may lead to an entangled network at a relatively low emulsion concentration, because of their ability of adsorption and unfolding on the interface, and the ability of viscoelastic interfacial film formation through molecular interactions [12]

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