2.2.3. Textural properties
The dried rice noodle is fully gelatinized during steaming process, so the cooking process is actually the rehydration process. A cooking time at 100 °C for 4 min is considered as the optimum cooking time because the water content of the cooked rice noodle at 4 min is equal to the water content of the fresh rice noodle (data not shown). Thus, the dried rice noodles were boiled at 100 °C for 4 min for textural measurement in this work. The cooked rice noodle was wound twice around parallel rollers for spaghetti-noodle testing (Lloyd Instruments Ltd, Fareham, U.K.). The maximum force (N) and extension maximum load were determined at a test speed of 100 mm/min and an extension limit of 70 mm. At least, 10 cooked noodle strands were measured for a replicate. This experiment was done in triplicate. The tensile strength (Pa) and elongation at break (%) were calculated according to Yalcin and Basman (2008) as shown Eq. (1) and Eq. (2).
equation(1)
View the MathML sourceTensilestrength=Force(N)/Thecross-sectionalareaofthenoodlestrand(m2)
equation(2)
View the MathML sourceElongation(%)=((Initiallengthofnoodlestrand−Lengthofnoodleatbreak)/Initiallengthofnoodlestrand)×100