Abstract
Rice noodles are one of rice products which are widely consumed in Asia. Since amylose
network plays an important role in structure of rice noodles, high amylose rice is usually
used for making rice noodles. However, rice noodles made from different cultivars give
different qualities. Unfortunately, mixed cultivars rice flour was usually used to produce rice
noodles in industry, leading to high variation in noodle qualities. Therefore, the objective
of this research is to investigate the effect of mixed flour made from various high amylose
rice cultivars on chemical composition, pasting properties, and texture of fresh rice noodles.
Simplex-centroid mixture design was applied to mixed 3 rice cultivars (Chainat1 (CNT1),
Pitsanulok2 (PSL2), and Suphanburi1 (SPR1)) into 7 formulas. All rice cultivars had similar
amylose (30.61-31.28%), fat (0.09 – 0.11%), and ash content (0.25 – 0.30%). Protein content of SPR1 (7.77 ± 0.01%) was the highest, following by CNT1 (6.53 ± 0.09%) and PSL2 (6.15 ± 0.16%), respectively (p≤0.05). PSL2-SPR1 mixed rice flour had amylose content (31.95 ± 0.21%) significantly higher than predictive value (31.09 ± 0.20%) (p≤0.05). Even though the amylose content values of all rice cultivars were similar, CNT1 had the highest, while SPR1 had the lowest setback and final viscosity among samples. Setback and final viscosity of all mixed formulas were slightly different from the predictive value (less than 10% difference). Hardness of CNT1-PSL2-SPR1 noodles (18291.20 ± 830.98 g) was obviously lower than predictive value (21040.29 ± 332.11 g). This might be an influence of CNT1 which had the lowest hardness (19323.05 ± 1789.57 g) among all cultivars. CNT-PSL noodles had noticeably lower adhesiveness (154.68 ± 33.55 g.sec) than predictive value (202.90 ± 14.68 g.sec). This might be an influence of PSL 2 which had the lowest adhesiveness (118.54 ± 42.85 g.sec). However, the variation in texture of mixed flour rice noodles was not directly proportional to the ratio of each rice cultivars in mixed flour. It can be said that in order to design the texture of rice noodles from mixed high amylose rice flour, it cannot be calculated based on only the textural data of pure cultivar with the mass percentage of each cultivar. The alteration effect from mixing should be considered.
