Branched chain length distribution of amylopectin in rice flour as a key attribute for determining the quality of extruded rice noodles

Abstract

The objective of this study was to investigate the effects of the branched chain length (BCL) distribution of amylopectin and crystallinity on the gelatinization property and the quality of extruded rice noodle. From the three different types of rice flour (Palbangmi [PBM], Saegoami [SGAM], and Mimyeon [MM]) with high amylose contents, MM displayed higher levels of longer amylopectin branched chain and higher crystallinity than the other flours. Moreover, MM showed higher gelatinization temperature and enthalpy than PBM and SGAM despite their similar amylose contents due to the different structural composition. As a result, dried noodle strands prepared with MM exhibited poor internal structure due to the insufficient gelatinization of rice flour during extrusion. In conclusion, BCL distribution of amylopectin and the crystallinity of rice flour could be important attributes in determining the quality of extruded rice noodles. Novelty impact statement Amylose content is recognized as the most important determinant of the quality of rice noodles; however, other factors also contribute to the production of high-quality noodles. In this study, three different types of rice flour with high amylose contents (more than 25%) were used to investigate the effects of the branched chain length (BCL) distribution of amylopectin on the quality of extruded noodles. The noodles prepared with rice flour containing higher levels of longer amylopectin branched chain showed undesirable texture and high cooking loss, suggesting that amylopectin BCL distribution substantially affected noodle quality.