The impact of glucono delta‐lactone (GDL) on rice flour pasting properties and GDL’s dipping effects on the quality of rice noodles

In this study, fresh rice noodles were treated by glucono delta‐lactone (GDL) dipping and in‐pack pasteurization. Rice flour pasting analysis showed that the final viscosity and setback values increased with a progressive increase in GDL concentration, indicating that acid addition promotes rice gel retrogradation. This was substantiated by the texture profile analysis results, where the hardness value of the gel formed with GDL was harder than the control. It was found that when rice noodles were subjected to the treatments, the noodle strands were easily detached from one another. It is speculated that starch molecules present on the surface retrograded faster than those counterparts present in the core of the noodles strand. Thus, a dry protective layer might form to prevent the moisture migration. Desorption analysis results support this explanation, where treated noodles were found to show a higher moisture retention level and had a lower retrogradation index. Practical applications Fresh rice noodles have a short shelf life due to microbial risk and starch retrogradation. So, it is common that fresh rice noodles can only be made available in certain areas near the manufacturers. By dipping fresh rice noodles in an acidic glucono delta‐lactone bath followed by in‐pack pasteurization, the quality of noodles was dramatically improved. The treatment has successfully delayed the onset of long‐term retrogradation of fresh rice noodles. These findings bring great benefits to the manufacturers as the distribution network of fresh rice noodles might be extended to both new and existing customers.