Effect of Calcium Sulfate and Magnesium Sulfate on Physical Properties of Gluten-Free Instant Noodle Made from Mixed Flours and Pea Protein

The objective of this study was to investigate the effect of calcium and magnesium salts on the physical properties of gluten-free instant noodles made from a mixture of rice flour, corn flour, flaxseed flour, and pea protein. Calcium sulfate and magnesium sulfate were added at concentrations of 0-0.4% (w/w). The ingredients were mixed, and the resulting dough was kneaded and pressed through a noodle maker into boiling water at 97 oC for 2 minutes. The obtained noodles were allowed to rest for 1 hour before being dried in a tray dryer at 70 oC for 3 hours. The results showed that the water activity of the treatment ranged from 0.25-0.32. Noodles containing 0.4% calcium sulfate had the highest water activity (p≤0.05). Cooking time increased with increasing concentration of calcium sulfate, whereas it decreased with increasing concentration of magnesium sulfate. The hardness of noodles increased with increasing concentration of calcium sulfate or magnesium sulfate, with noodles containing 0.4% magnesium sulfate exhibiting the highest hardness (p≤0.05). The addition of calcium sulfate or magnesium sulfate significantly decreased noodle adhesiveness (p≤0.05). The brightness of the noodles containing magnesium sulfate was lower than that of the control (p≤0.05).