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uickly in mild steel or galvanised equipment. taining the blanching liq arises from the necessity to reduce leaching losses, which have also been referred to in the context of lye peeling. Retention of blanching liquor permits solids leached out, at the beginning of the blanching process, to build up fairl kly to a level where fresh material up its solids so readily, and a liquor of relatively high density is created. By using the buffering technique hitherto described, it has been proved conclusively that the solids content in blanched vegetables can be in excess of that in raw, unblanched material, and this can affect the ultimate yield of the dry material dramatically n exception to this procedure is in the blanching of potatoes. Here the solids are in the form of free starch released from the cut surface of the potato, and it is necessary that this be washed away, as it creates drying problems by causing a condition of impermeability to arise in the bed of material in the dryer, with serious detriment to the air flow. Also, an ccumulation of starch in the blancher sometimes sets up uncontrollable foaming. In this case an anti-foaming agent can be used Blanchers should be selected only after careful consideration has been given to their design features relating to hygiene and easy cleaning. Unlike quipment used in canneries, which may operate on a day shift basis, the blancher in a dehydration factory has to work continuously for some 150h week, and it is absolutely essential that its construction takes this into account, and that raw material is not left behind in augers, crevices and inaccessible parts of the machine. The inside of the blancher should be easily and quickly accessible for weekend cleaning and sterilisation CONVEYORS The approach plant and conveying systems should all be constructed in stainless steel, wherever contact with the prepared vegetables takes place Where gooseneck elevators are used, the buckets should be of plastics or moulded rubber Conveyor belts should be PVC-covered and manufactured to the highest sanitary standards The conveying system from the blancher to the dryer should be rranged to allow as little delay as possible in transferring blanched material to the first stage of drying, as a high bacterial count can build up at this point, if this precaution is not taken. This condition is aggravated where cooling does not take place after blanching. Where it is desirable to retain the additive level in blanched vegetables with a minimum of loss, water cooling after blanching is often omitted but it is essential, in these circumstances, that the drying process starts immediately and the blanched vegetables are not leftquickly in mild steel or galvanised equipment. The desirability of retaining the blanching liquor for long periods arises from the necessity to duce leaching losses, which have also been refed to in the context of lye peeling. Retention of blanching liquor permits solids leached out, at the beginning of the blanching process, to build up fairly quickly to a level where fresh material passing thmugh no longer gives up its solids so readily, and a liquor of relatively high density is created. By using the buffering technique hitherto described, it has been proved conclusively that the solids content in blanched vegetables can be in excess of that in raw, unblanched material, and this can affect the ultimate yield of the dry material dramatically. An exception to this prpcedure is in the blanching of potatoes. Here the solids are in the form of free starch, released from the cut surface of the potato, and it is necessary that this be washed away, as it creates drying problems by causing a condition of impermeability to arise in the bed of material in the dryer, with serious detriment to the air flow. Also, an accumulation of starch in the blancher sometimes sets up uncontrollable foaming. In this case an anti-foaming agent can be used. Blanchers should be selected only after careful consideration has been given to their design features relating to hygiene and easy cleaning. Unlike equipment used in canneries, which may operate on a day shift basis, the blancher in a dehydration factory has to work continuously for some 150hr a week, and it is absolutely essential that its construction takes this into account, and that raw material is not left behind in augers, crevices and inaccessible parts of the machine. The inside of the blancher should be easily and quickly accessible for weekend cleaning and sterilisation. CONVEYORS The approach plant and conveying systems should all be constructed in stainless steel, wherever contact with the prepad vegetables takes place. Where gooseneck elevators are used, the buckets should be of plastics or moulded rubber. Conveyor belts should be PVC-covered and manufactured to the highest sanitary standards. The conveying system from the blancher to the dryer should be arranged to allow as little delay as possible in transferring blanched material to the first stage of drying, as a high bacterial count can build up at this point, if this precaution is not taken. This condition is aggravated where cooling does not take place afterblanching. Where it is desirable to retain the additive level in blanched vegetables with a minimum of loss, water cooling after blanching is often omitted but it is essential, in these circumstances, that the drying process starts immediately and the blanched vegetables are not left 53
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