Abstract

Wheat is one of the top three most important foodstuffs and commodities in the world with approximately 600 tonnes harvested each year. Wheat is an important constituent of many products, mainly bread and pasta products. Wheat flour has the ability to form gluten; a protein matrix created from agitation of two proteins, glutenin and gliadin, in the presence of water. The matrix is mostly formed during the mixing and extrusion process. In breads gluten provides elastoplastic properties, in pasta it provides structure and rigidity. An estimated of 0.71% of Americans have Celiac disease, an adverse effect in the small intestine caused by the consumption of gluten. Beyond Celiac disease, many suffer from wheat allergies and gluten intolerances, many more maintain gluten free diets due to sensitivities and millions more do so for weight loss or perceived healthfulness; an estimated 20% of American consumers take active steps towards a gluten free diet. Gluten-free products often have reduced texture and sensory characteristics compared to their glutenous counterparts, often leading to decreased consumption. The objective of this work was to determine sensory aspects of gluten-free and glutenous bread and pasta products and relate them to their chemical properties. For pasta: an acceptance sensory test was conducted between semolina, whole wheat, and protein enriched gluten-free pasta (n=137). Physico-chemical tests were conducted to determine differences in protein matrix formation and structure. For bread: a discriminatory (n=26), descriptive (n=13), and acceptance test (n=53) were conducted between glutenous and gluten-free bread. It was found that differences in texture between products led to both higher discrimination and differences in preference, and that these differences may be viewed at a chemical level. Overall it was determined that glutenous and gluten-free breads have significantly different hedonic scores; however, the addition of protein may mimic the gluten network leading to changed sensorial aspects. 

Abstract

Pasta is a product eaten all over the world. Much of pasta's properties come from gluten, however, those with Celiac disease have an adverse reaction to its consumption. Legume proteins have the possibility of mimicking the gluten network to create gluten-free pasta. The objective of this work was to use legume proteins to create gluten-free pasta enriched with protein. A two component mixture design of pea protein isolate (PPI) and fava bean protein isolate (FPI) was followed (100%PPI, 100%FPI, 50:50, 25:75 and 75:25 PPI:FPI ratios). The PPI and FPI mixtures were added into a base formulation containing rice flour, tapioca starch, and xanthan gum to create pasta using cold extrusion. Samples were tested for extrusion feasibility, optimal cooking time, cooking loss, swelling index, color and hardness. There was a non-significant difference (p>0.05) in extrusion flow rates. FPI addition significantly reduced (p<0.05) cooking loss in all mixtures. It was shown that FPI improves the cooking parameters, while the addition of PPI yields a more structurally rigid pasta. Optimization using Minitab Statistical Software and considering semolina pasta extruded in our laboratory as the standard, resulted in a 30:70 PPI:FPI optimal formulation when all parameters had same importance, and 43:57 PPI:FPI when extrusion flow rate, cooking loss, and hardness had highest importance. This research shows a feasible and efficient way to formulate protein enriched gluten-free products and highlights the use of legumes as a protein source for said products. These types of products meet a growing trend of gluten-free and high-protein foods.