Chitosan effects on physical properties, texture, and microstructure of flat rice noodles

- Acetic acid induced the formation of protein networks in flat rice noodles.
- The induced protein networks restricted the interference effects of chitosan.
- Chitosan decreased the whiteness of rice flour noodles.
- Chitosan retarded the increase of rice flour gel hardness during storage.
- Chitosan retarded the decrease of rice flour gel springiness during storage.

The use of chitosan as a natural preservative has increased for rice-based products, but little is known about chitosan effects on product quality. This work elucidated chitosan effects on the physical properties (moisture content, pH, and color), texture, and microstructure of flat rice noodles. Chitosan solutions (0.33 and 0.50 g chitosan/100 mL acetic acid) were added to rice flour noodles. Chitosan exhibited no effect on moisture contents, but it decreased the rice noodle pH and whiteness. Confocal laser scanning micrographs revealed that acetic acid caused protein network formation in rice noodles. Chitosan did not affect textural properties of rice flour gel because the acetic-acid-induced protein networks inhibited chitosan effects. During storage at 30 °C for 5 d, chitosan retarded increases in the hardness and gumminess and decreases in the cohesiveness and springiness of rice flour gel. Results show that chitosan is useful as a preservative in rice flour noodles without adversely affecting noodle quality.