Effect of molar weight of gelatin in the coating of alginate microparticles

Joelma Correia Beraldo,Carlos Raimundo Ferreira Grosso,Gislaine Ferreira Nogueira,Ana Silvia Prata

doi:10.1590/0104-1428.20210027

Joelma Correia Beraldo, Carlos Raimundo Ferreira Grosso + Show 2 more

Open Access

https://doi.org/10.1590/0104-1428.20210027

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Abstract

Abstract The protein adsorption on the porous alginate microparticles was evaluated in regards to the coating ability and this protective effect during gastrointestinal assay. The coating was performed at suitable pH for optimized electrostatic interaction between protein and alginate. Concentrations of gelatin (HGE) and their hydrolysates (Collagel® (MGE) (> 10 kDa) and Fortigel® (LGE) (3 kDa)) from 1 to 10% (w/w) were tested. Higher protein adsorption was observed in the highest concentration of protein in solution and the amount adsorbed was inversely proportional to the degree of hydrolysis with 47.3, 41.4 and 29.3% of protein adsorbed when HGE, MGE and LGE were used, respectively. The particles that showed higher protein adsorption were submitted to gastrointestinal in vitro assay. In gastric simulation, 39.1, 41.8 and 49.0% of protein from HGE, MGE and LGE were solubilized while 81.3, 61.5 and 95.2% were solubilized after 5 h under enteric conditions.

Highlights

Ionic gelation (IGEL) is one of the most used techniques for encapsulation of sensitive, bioactive, and functional compounds[1,2,3,4], cells and probiotic bacteria[5,6], due to the mild conditions employed, ie, absence of heating or organic solvents and moderated stirring rate conditions[1]
Gelatin (HGE) has a positive charge below its isoelectric point (IEP) and can interact with alginate, an anionic polysaccharide, above its pKa values[11]. It is obtained from collagen through acid or alkaline hydrolysis[12] and its molecular weight (MW) varies from 300-200.000 Da depending on the raw material and the process conditions[13]
Appropriate range of interaction between gelatin and their hydrolisates was found to promote their adsorption on the alginate microparticles

Summary

Introduction

Ionic gelation (IGEL) is one of the most used techniques for encapsulation of sensitive, bioactive, and functional compounds[1,2,3,4], cells and probiotic bacteria[5,6], due to the mild conditions employed, ie, absence of heating or organic solvents and moderated stirring rate conditions[1]. Layer-by-layer protein deposition onto gelled particles has been successfully employed aiming to increase the resistance in gastric conditions[8,9,10] or to reduce the losses of hydrophilic compounds to the product[1]. Gelatin (HGE) has a positive charge below its isoelectric point (IEP) and can interact with alginate, an anionic polysaccharide, above its pKa values[11]. It is obtained from collagen through acid (type A, IEP, 7.0-9.0) or alkaline hydrolysis (type B, IEP, 4.6-5.2)[12] and its molecular weight (MW) varies from 300-200.000 Da depending on the raw material and the process conditions[13]. The conditions for EI between type A HGE and two commercial hydrolysates of collagen, Collagel® (MGE, > 10 kDa) and Fortigel® (LGE, 3kDa)

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Conclusion