Textural behavior of gels formed by rice starch and whey protein isolate: Concentration and crosshead velocities

Thiago Novaes Silva,Angélica Ribeiro Da Costa,Edwin Elard Garcia-Rojas

doi:10.1590/1413-70542017416012317

Thiago Novaes Silva, Angélica Ribeiro Da Costa + Show 1 more

Open Access

https://doi.org/10.1590/1413-70542017416012317

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Abstract

ABSTRACT Fabricated food gels involving the use of hydrocolloids are gaining polpularity as confectionery/convenience foods. Starch is commonly combined with a hydrocolloid (protein our polyssacharides), particularly in the food industry, since native starches generally do not have ideal properties for the preparation of food products. Therefore the texture studies of starch-protein mixtures could provide a new approach in producing starch-based food products, being thus acritical attribute that needs to be carefully adjusted to the consumer liking. This work investigated the texture and rheological properties of mixed gels of different concentrations of rice starch (15%, 17.5%, and 20%) and whey protein isolate (0%, 3%, and 6%) with different crosshead velocities (0.05, 5.0, and 10.0 mm/s) using a Box-Behnken experimental design. The samples were submitted to uniaxial compression tests with 80% deformation in order to determinate the following rheological parameters: Young’s modulus, fracture stress, fracture deformation, recoverable energy, and apparent biaxial elongational viscosity. Gels with a higher rice starch concentration that were submitted to higher test velocities were more rigid and resistant, while the whey protein isolate concentration had little influence on these properties. The gels showed a higher recoverable energy when the crosshead velocity was higher, and the apparent biaxial elongational viscosity was also influenced by this factor. Therefore, mixed gels exhibit different properties depending on the rice starch concentration and crosshead velocity.

Highlights

Rice starch (RS) is the basic food of almost half of the population worldwide; it has great global, social, and political economic importance (Tan; Sun; Corke, 2002)
90% of the total dry weight of the polished rice grain is composed of starch, which is the main plant polysaccharide that occurs naturally in the form of granules in vegetable cells (Singh et al, 2003)
Due to the increased consumption of gluten-free products, which include RS, and the limited amount of research in this area, the aims of this study were to evaluate the texture properties of mixed gels containing RS and whey protein isolate (WPI) and to elucidate how they are influenced by crosshead velocity

Summary

Introduction

Rice starch (RS) is the basic food of almost half of the population worldwide; it has great global, social, and political economic importance (Tan; Sun; Corke, 2002). 90% of the total dry weight of the polished rice grain is composed of starch, which is the main plant polysaccharide that occurs naturally in the form of granules in vegetable cells (Singh et al, 2003). RS is hypoallergenic, white in color, and has a smooth texture when it is in the form of a gel (Viturawong; Achayuthakan; Suphantharika, 2008). Starch is commonly combined with a hydrocolloid, in the food industry, since native starches generally do not have ideal properties for the preparation of food products. These combinations are used to modify the rheological and texture properties in order to improve humidity retention, control water mobility, and maintain general product quality during food processing and storage (Samutsri; Suphantharika, 2012)

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