IMPACT OF CALCIUM HYDROXIDE ON THE TEXTURAL PROPERTIES OF BUCKWHEAT NOODLES

The effects of calcium hydroxide on the textural properties of buckwheat noodles were studied to elucidate the mechanism of textural improvement for commercial production. The addition of calcium hydroxide significantly (P < 0.05) affected the textural parameters in a dose-dependent manner. The highest values of tensile strength and cutting force of cooked buckwheat noodles were obtained simultaneously with a mass fraction of 0.4% calcium hydroxide. Further increases in the quantity of calcium hydroxide resulted in decreases in both parameters. Low mass fractions of calcium hydroxide (=0.4%) might promote swelling and rupturing of the starch granules through formation of Ca2+-starch and Ca(OH)+-starch complexes. Release of amylose from the starch granules enhanced formation of a compact and homogeneous buckwheat noodle. Scanning electron microscopy observations confirmed that the microstructure of the cooked noodles containing 0.4% calcium hydroxide was more compact and homogeneous, and less porous than that of control. PRACTICAL APPLICATIONS Because of their lack of gluten, pure buckwheat noodles are difficult to produce and their sensory characteristics are not fully acceptable compared with common wheat noodles. Introduction of calcium hydroxide into buckwheat noodles can greatly improve their textural properties. Because calcium is essential in the human diet, calcium hydroxide is an ideal additive for the manufacture of buckwheat noodles. The results of this work will provide a theoretical basis for commercial production of pure buckwheat noodles and improvement of the textural properties of other gluten-free foods.