the flask, with 10ml of concentrated hydrochloric acid. Heat is applied to bring about boiling in 2-3min. The distillate is collected in 200ml of water in the beaker at the bottom of the condenser, and n/100 iodine is titrated from a burette to maintain a slight excess of iodine. A little starch solution indicator is added to the beaker A marked reduction in the rate of evolution of iodine combining substances is taken as the end-point, or when more than one minute is required to decolorise 0. 2mI N/100 iodine. The distillation should be complete in 5-10min Calculations: Iml N/100 iodine titrated =0.32mgm sulphur dioxide Peroxidase Test for Vegetables During blanching, the enzymes present in active form become progressively inactivated by heat. Of these enzymes, the peroxidase complex is readily perceived because of the colour reaction it promotes with a reagent A suitable reagent is a solution of Guaiacol and hydrogen peroxic made as follows: (1)1 per cent w/v Guaiacol dissolved in distilled water )Mix 25ml of 20 volume hydrogen peroxide in 75ml of water, and add 100ml of 1 per cent Guaiacol solution. The sample for analysis is liberally wetted by the above solution, and the development of a brown colour indicates active, or positive, peroxidase. If the colour is not apparent in one minute, the result is negative, and it can be assumed that blanching is adequate If the result is positive, it is necessary to adjust the blanching conditions, either by increase of temperature or product immersion time Blemish Count A limited number of minor blemishes is often permitted, commercially, in dehydrated vegetables but the tolerance must be rigorously controlled Blemish may arise from disease in the fresh vegetable, skin, root or growth defect, or can stem from a processing fault, such as scorching, under or overblanching, or inefficient peeling Obvious blemish should not be present, and the only tolerated blemish is what is described as ', ie, slight blemish in the dry state, which mainly isappears on reconstitution. The standard will obviously vary from processor to processor but, on of dehydrated vegetable. A similar standard applies to meat in a 50g sample average the permitted tolerance is from 5-7 minor blemishesthe flask, with 10ml of concentrated hydrochloric acid. Heat is applied to bring about boiling in 2-3min. The distillate is collected in 200ml of water in the beaker at the bottom of the condenser, and N/100 iodine is titrated from a burette to maintain a slight excess of iodine. A little starch solution indicator is added to the beaker. A marked reduction in the rate of evolution of iodine combining substances is taken as the end-point, or when more than one minute is required to decolorise 0.2ml N/100 iodine. The distillation should be complete in 5-l0min. Calculations: lml N/100 iodine titrated = 0.32mgm sulphur dioxide. Peroxidase Test for Vegetables During blanching, the enzymes present in active form become progressively inactivated by heat. Of these enzymes, the peroxidase complex is readily perceived because of the colour reaction it promotes with a reagent. A suitable reagent is a solution of Guaiacol and hydrogen peroxide made as follows: (1) 1 per cent w/v Guaiacol dissolved in distilled water: (2) Mix 25ml of 20 volume hydrogen peroxide in 75ml of water, and add 100ml of 1 per cent Guaiacol solution. The sample for analysis is liberally wetted by the above solution, and the development of a brown colour indicates active, or positive, peroxidase. If the colour is not apparent in one minute, the result is negative, and it can be assumed that blanching is adequate. If the result is positive, it is necessary to adjust the blanching conditions, either by increase of temperature or product immersion time. Blemish Count A limited number of minor blemishes is often permitted, commercially, in dehydrated vegetables but the tolerance must be rigorously controlled. Blemish may arise from disease in the fresh vegetable, skin, root or growth defect, or can stem from a processing fault, such as scorching, under or overblanching, or inefficient peeling. Obvious blemish should not be present, and the only tolerated blemish is what is described as ‘minor’, ie, slight blemish in the dry state, which mainly disappears on reconstitution. The standard will obviously vary from processor to processor but, on average, the permitted tolerance is from 5-7 minor blemishes in a 50g sample of dehydrated vegetable. A similar standard applies to meats. 235