Preparation Of Rice Flour Essay

MATERIALS AND METHOD

3.1 Preparation of Rice Flour

Rice samples with high amylose (Bg 360) and low amylose (At 405) was collected from Ambalangoda Rice Research Institute. Dry- milling method was used to both high amylose and low amylose rice. Rice grains were grounded, separately using a pin mill (Alpine, Augsburg, Germany). Then it was sealed in polypropylene plastic bags and stored in a desiccator at room temperature until further analyses.

3.2 Analysis of physicochemical properties of rice flour

3.2.1 Amylose content

Amylose content was measured according to procedure reported by Juliano (1971). Flour sample of 100±0.01 mg (db) was measured into a conical flask and 1.0 ml of 95 % ethanol and 9 ml of NaOH were added. After that, sample was gelatinized by heating on a water bath (Yamato, BS 69, Japan) for 10 minutes. Amount of 5 ml of diluted solution was put in a 100 ml volumetric flask. Then 1.0 ml of 1.0

Approximately 50 g of each sample were placed in a 5‐cm diameter glass petri dish with an opaque cover. After the first color measurement was taken, the sample petri dish was rotated 90° and next measurement was performed. Viscosity of starch Viscosity at different shear rate

Viscosity of starch was measured according to method of ISI. (2002). Starch samples of 8% was heated to 95 ºC at a constant rate of 1.45 ºC /min on the hot plate with continuous stirring. During heating process, sample containing beaker was kept in a water bath to prevent temperature loss. After keeping the sample for 20 min at 95ºC, sample was cooled in running water to 50ºC. Viscosity was measured using spindle 4 of coaxial viscometer (RL,16 BL, Japan) using different shear rate at different temperature 45ºC,55 ºC,65 ºC,75 ºC,85 ºC,95 ºC and 50 ºC after immediate cooling. Alternative method for Visco-amylograph