Evaluation of amaranth flour processing for noodle making

Abstract

Amaranth is an ancient grain that is high in gluten-free protein and is a drought tolerant crop. Due to growing consumer interest in nutrition and environment, there is a renewed interest in ancient crops such as amaranth. The objective of this study was to evaluate processing methods such as dry roasting and jet-cooking of amaranth flours for making high protein, gluten-free noodles. Commercial amaranth flour was processed by dry roasting and excess steam jet-cooking. The raw and processed flours were evaluated for proximate and amino acid composition, physical properties such as bulk density, water absorption, and pasting and properties and compared to wheat flour. The noodle dough and noodles made using the three amaranth flours and wheat flour were evaluated for texture, color, and cooking quality. Raw amaranth flour had higher protein, ash, and fat content but lower starch content when compared to wheat flour. Processing of amaranth flour did not affect the protein, starch, and ash content of amaranth flours. Bulk density of raw amaranth flour was significantly lower than wheat flour roasting did not affect the bulk density, but jet-cooking decreased the bulk density. Raw amaranth flour had higher peak viscosity than wheat flour. The jet-cooked amaranth flour had a shorter hydration time, lower peak viscosity, and low setback. Raw Amaranth noodle dough was softer but roasted amaranth flour did not significantly differ in dough hardness from wheat flour dough. The noodles made from raw and processed amaranth flours were softer than wheat flour noodles. Amaranth flour noodles had a softer bite than wheat flour noodles, roasting increased the hardness of the amaranth flour noodles. Raw and roasted amaranth flours had similar cooking yields as wheat flour, but jet-cooked amaranth flour noodles had higher cooking losses and partially disintegrated during cooking. Roasted amaranth flour has potential for replacing wheat flour in the preparation of acceptable gluten-free, nutritive noodles. Practical Application Roasted amaranth flour has potential for replacing wheat flour in the preparation of acceptable gluten-free, nutritive noodles. Amaranth crop is drought tolerant, and amaranth grain is high in protein, rich in essential amino acids and is gluten- free. Roasting a simple dry heat process and jet-cooking a high heat and shear process was applied to improve the nutrition and digestibility of amaranth flour. The raw, roasted, and jet-cooked amaranth flour was evaluated, and characteristics compared to wheat flour. Noodles made from amaranth flours were compared to wheat flour noodles. This work demonstrates that roasting improved the cooking yield and texture of cooked noodles. This will expand utilization of amaranth and contribute to the sustainability of U.S. agriculture in the era of climate change.