Development of gluten-free pasta using amaranth flour and pea protein flour

Abstract

<p>About 40 million people in the U.S. are suffering from gluten-related diseases, resulting in the increased demand for gluten-free products. However, the challenge in developing a gluten-free product is to produce a viscoelastic network in the absence of gluten. The present study aimed to develop a gluten-free pasta using pea protein flour (PPF) and amaranth flour (AF).</p> <p>The effect of the addition of pea protein flour at concentrations of 5%, 10%, 15% and 20% to 95%, 90%, 85% and 80% AF respectively were studied. The effect of extruder screw speeds 110 rpm, 450 rpm, and 900 rpm was studied as well. As it has been reported that high-temperature drying has a positive effect on wheat pasta, gluten-free pasta was also studied at various temperature-time combinations. The effect of drying temperatures of 60°C, 80°C, and 100°C for both 12hr and 24hr was studied. To observe the effect of all the parameters, tests such as water absorption capacity, cooking loss, unit density, and color were conducted on the obtained products.</p> <p>The addition of PPF at 20% concentration to AF increased the protein content from 17.3g to 25.6g. For 20% addition of pea protein flour, cooking losses decreased by 31% and firmness increased by 74.34%.</p> <p>As drying temperature increased from 60°C to 100°C, water absorption capacity increased by 16.46% and cooking loss decreased by 59.09%. However, with an increase in drying temperature to 100°C, L* (lightness) value and b* (yellowness) value decreased by 32.35% and 18.69%, respectively, while a* (redness) value increased by 20.54% resulting in a darker product. Negative impact on product unit density was observed as well as it decreased by 32.35% with increase in temperature from 60°C to 100°C.</p> <p>The significant negative effect of high screw speed was observed on pasta unit density, water absorption capacity and cooking loss. High screw speeds resulted in unacceptable puffed products resulting from the flash off process. Water absorption decreased by 90% and cooking loss increased by 110.9% with an increase in screw speed from 110 to 900 rpm. Only, pasta prepared at 110 rpm was unpuffed (acceptable).</p> <p>According to this study, we conclude that high protein content and drying temperature have a positive effect on pasta firmness, cooking properties, and unit density. On the other hand, pasta of low density was obtained at a very high screw speed. Overall, results showed that firmer pasta with compact structure was obtained when formulated using 80% AF and 20% PPF, drying at 80°C for 12 hrs and extruding at 110 rpm.</p> <p>Even though various aspects of pasta manufacturing were studied, the pasta characteristics were still found to be inferior to the benchmark (Barilla gluten-free pasta. Further studies with emulsifier addition should be done to improve the pasta texture. To avoid the puffing of the product, an extruder with controlled barrel temperature should also be used in the future to study the effect of screw speed. To obtain pasta of a better appearance, the effect of drying pasta at various temperatures should be studied, instead of drying at a constant temperature for the whole drying cycle.</p>