along the length. The angle of the paddles to the line of the shaft is variable so that the flow of material can be accelerated or decelerated, as may be required, to thoroughly mix the product Mashing, and mixing in the add-back granules or'seed powder at this point must be gentle to avoid cell rupture, and the speed of the mixer is critical. The seed powder is continuously fed into the mixer at the point where the cooked potatoes enter, at a rate in excess, by weight, of the potatoes The average proportions might be 35 percent potato to 65 percent seed powder but this can only be established by practice, and will vary according to the solid matter in the raw potato, and, conversely, the moisture content of the seed. The ultimate objective is to obtain a blend with 35-40 percent moisture; the arrangement whereby the seed powder is available continuously at the mixer is described later The blend of cooked potato and add-back seed fills up the trough mixer, and is then allowed to fall over a weir, through an aperture in the end plate, into a second mixer of longer but shallower proportions. The purpose of this second mixer is to extend the mixing period, at the same time allowing the blend to cool as it travels along the trough. As stated before, the rate of travel is controlled by the of the paddles, and thor will take 25-35 min Sulphite and other additives, which may be required, are added to the blend by a suitable metering device, during the mixing Process No general rule can be applied as to the additives, as Food Laws differ from country to country, and the processor must familiarise himself with what is permitted, and what is not, in his own particular market. Additiv may include sodium metabisulphite, acid sodium pyrophosphate monostearates, anti-oxidants, flavourings and milk powde Sulphur Pyrophosphate, anti-oxidants, and sometimes milk powder are mixed with potato granules to make a ' master mix whereby the metering into the mash can be more accurately gauged and, by dilution, can be assimulated more evenly than small quantities of separate ingredient Glycerol monostearate in solution is metered in At the end of the second mixer, the blend again falls over a weir and passes to a conditioning bin, where the material cools to about 24"C in our wo bins are normally used, one being filled whilst the other is conditioning. This conditioning is a most important stage in the process, as it assists granulation and retrogradation of the starch From the bottom of the conditioning bin, the blend feeds into the first stage of drying. The primary dryer can be either (a)a pneumatic ring dryer, or(b)a thermal venturi dryer, both of which were described in Chapter IV a suitable feeding arrangement is required for the particular type of dryeralong the length. The angle of the paddles to the line of the shaft is variable, so that the flow of material can be accelerated or decelerated, as may be required, to thoroughly mix the product. Mashing, and mixing in the add-back granules or ‘seed’ powder at this point must be gentle to avoid cell rupture, and the speed of the mixer is critical. The seed powder is continuously fed into the mixer at the point where the cooked potatoes enter, at a rate in excess, by weight, of the potatoes. The average proportions might be 35 percent potato to 65 percent seed powder but this can only be established by practice, and will vary according to the solid matter in the raw potato, and, conversely the moisture content of the seed. The ultimate objective is to obtain a blend with 35-40 percent moisture; the arrangement whereby the seed powder is available continuously at the mixer is described later. The blend of cooked potato and add-back seed fills up the trough mixer, and is then allowed to fall over a weir, through an aperture in the end￾plate, into a second mixer of longer but shallower proportions. The purpose of this second mixer is to extend the mixing period, at the same time allowing the blend to cool as it travels along the trough. As stated before, the rate of travel is controlled by the angle of the paddles, and thorough granulation will take 25-35 min. Sulphite and other additives, which may be required, are added to the blend by a suitable metering device, during the mixing process. No general rule can be applied as to the additives, as Food Laws differ from country to country, and the processor must familiarise himself with what is permitted, and what is not, in his own particular market. Additives may include sodium metabisulphite, acid sodium pyrophosphate, monostearates, anti-oxidants, flavourings and milk powder. Sulphur Pyrophosphate, anti-oxidants, and sometimes milk powder are mixed with potato granules to make a ’master mix‘ whereby the metering into the mash can be more accurately gauged and, by dilution, can be assimulated more evenly than small quantities of separate ingredients. Glycerol monostearate in solution is metered in. At the end of the second mixer, the blend again falls over a weir and passes to a conditioning bin, where the material cools to about 24°C in an hour. Two bins are normally used, one being filled whilst the other is ‘conditioning’. This conditioning is a most important stage in the process, as it assists granulation and retrogradation of the starch. From the bottom of the conditioning bin, the blend feeds into the first stage of drying. The primary dryer can be either (a) a pneumatic ring dryer, or (b) a thermal venturi dryer, both of which were described in Chapter IV. A suitable feeding arrangement is required for the particular type of dryer I09