Physiochemical properties of jet-cooked amaranth and improved rheological properties by processed oat bran

Abstract

The development of innovative gluten-free amaranth and oat bran mixtures using thermomechanical processing is important for producing products for consumers allergic to wheat proteins. This study intended to develop nutritious food ingredients using steam jet-cooked amaranth flour composted with 10-50% jet-cooked oat bran. The protein, ash, and amino acid contents of amaranth and oat bran flour were investigated along with measurements of water-holding capacity (WHC) and rheological properties. Results showed that amaranth and oat bran have higher protein and ash contents compared to wheat flour. The jet-cooked amaranth flour had decreased particle size and bulk density, whereas the jet-cooking process increased WHC and soluble solids, as well as improved viscoelasticity in comparison with untreated amaranth flour. The protein, ash, and amino acid contents were not influenced by jet-cooking process. Significant positive correlations were found between ash and protein, and between WHC, water absorption index (WAI) and swelling point (SP), respectively. In contrast, significant negative correlation was observed between both protein and ash with bulk density (p < 0.01). Results indicated that the hydro-thermal process and additional processed oat bran greatly enhanced WHC and viscoelastic property that are critical for mixing, cooking, and food applications such as smoothies and porridge products.

Keywords

• Amaranth
• Gluten-free
• Jet-cooking
• Oat bran
• Rheology
• Protein