BS EN ISO 6647-1:2020 pdf free.Rice – Determination of amylose content Spectrophotometric method with a defatting procedure by methanol and with calibration solutions of potato amylose and waxy rice amylopectin.
BS EN ISO 6647-1 Weigh (6.9) 100 mg土0,5 mg of the defatted and conditioned potato amylose into a 100 ml conical flask (6.8]. Carefully add 1 ml of ethanol (5.2), rinsing down any potato amylose adhering to the walls of the flask. Add 9,0 ml of 1 mol/1 sodium hydroxide solution (5.3) and mix. Then heat the mixture on a boiling water bath (6.7) for 10 min to disperse the potato amylose. Allow to cool to room temperature and transfer into a 100 ml volumetric flask [6.6].Make up to volume with water and mix vigorously.1 ml of this stock suspension contains 1 mg of potato amylose.If the test samples, the amylose and the amylopectin are conditioned in the same environment, no correction for moisture content is necessary and the results are obtained on a dry milled rice basis. If the test samples and the stocks are not prepared under the same conditions, the moisture content of both the samples and the stocks shall be determined as specified in ISO 712 and the results should be corrected accordingly. Stock amylopectin suspension, 1 g/L.Prepare the stock from milled glutinous (waxy) rice with a starch content known to consist of at least 99 % by mass of amylopectin. Steep the milled glutinous rice and blend in a suitable laboratory blender (6.1) to a finely divided state. Remove protein by exhaustive extraction with a detergent solution (5.5) or, alternatively, with a sodium hydroxide solution (5.6. Wash and then defat by refluxing with methanol (5.1) as described in 5.9.1. Spread the deproteinated and defatted amylopectin on a tray and leave for two days to allow evaporation of residual methanol and for moisture content equilibrium to be reached.
Carry out the procedure given in 5.9.3, but with amylopectin instead of amylose. 1 ml of this stock suspension contains 1 mg of amylopectin. The iodine binding capacity of amylopectin should be less than 0,2 % (see Annex A).Usual laboratory apparatus and, in particular, the following.BS EN ISO 6647-1 pdf download.
BS EN ISO 6647-1:2020 pdf free
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