Fabrication and Characterization of Ultra-High-Pressure (UHP)-Induced Whey Protein Isolate/κ-Carrageenan Composite Emulsion Gels for the Delivery of Curcumin.

Jiaqi Su,Xi Liu,Jiao Wei,Pengjie Wang,Jinxin Yan,Fazheng Ren,Fang Yuan,Linlin Wang,Wenxia Dong

doi:10.3389/fnut.2022.839761

Jiaqi Su, Xi Liu + Show 7 more

Open Access

https://doi.org/10.3389/fnut.2022.839761

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Abstract

The emulsion gels have attracted extensive interests due to their unique physical characters, remarkable stability, and control release properties of flavor and functional components compared to emulsions in liquid. In the current work, whey protein isolate (WPI)/κ-carrageenan (κ-CG) composite emulsion gels were fabricated based on the ultra-high-pressure (UHP) technology, in replacement of the traditional thermal, acid, or enzyme processing. Uniform composite emulsion gels could be fabricated by UHP above 400 MPa with minimum WPI and κ-CG concentrations of 8.0 and 1.0 wt%, respectively. The formation of UHP-induced emulsion gels is mostly attributed to the hydrophobic interaction and hydrogen bonding. The emulsion gels with different textures, rheology properties, and microstructures could be fabricated through adjusting the formulations (WPI concentration, κ-CG concentration, and oil phase fraction) as well as processing under different conditions (pressure and time). Afterward, curcumin-loaded emulsion gels were fabricated and subjected to an in vitro simulated gastrointestinal digestion in order to investigate the gastrointestinal fate of curcumin. In vitro simulated digestion results demonstrated that the UHP treatment significantly retarded the release of curcumin but had little impact on the bioaccessibility of curcumin. The results in this work provide useful information for the construction of emulsion gels through a non-thermal process, which showed great potential for the delivery of heat-sensitive bioactive components.

Highlights

Emulsions with a relatively low oil volume fraction are expected to exhibit liquid-like flow behavior
The results indicated that the α-coil content was significant decreased, while the β-sheet, β-turn, and randomcoil contents were increased when whey protein isolate (WPI) and κ-CG were combined under atmospheric pressure
The WPI/κ-CG composite emulsion gels were successfully prepared through UHP treatment

Summary

Introduction

Emulsions with a relatively low oil volume fraction are expected to exhibit liquid-like flow behavior. When a viscoelastic biopolymer solution or gel functions as a continuous phase, or an emulsion behaves as a viscoelastic material due to the structuring induced by interdroplet attractions between the droplets or crowded arrangement of droplets, a complex colloidal material may formed as both an emulsion and a gel Protein-based emulsion gels can be classified into two types: [1] Emulsion-filled protein gel: Protein in the aqueous phase forms a polymer network in which oil droplets are uniformly dispersed, and the gel properties mainly depend on the nature of the protein matrix and [2] Protein-stabilized emulsion gel: Protein in the aqueous phase does not form a network structure but promotes the aggregation of droplets, while the gel properties mainly depend on the physical properties of the filled oil droplets These two extreme structures typically coexist in a protein-based emulsion gel. A variety of proteins were used to prepare emulsion gels, including whey protein [2], sodium caseinate [3], soy protein isolate [4], porcine serum protein [5], and so on

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