3 Preparation Plant Preparation plant for dehydration is very similar to that used by th canner and freezer, because up to the last stage of conser material is prepared in similar manner, other than to provide for the introduction of certain additives which are not common to either canned or frozen products This chapter defines very briefly the type of preparation plant used in a multi-product operation, the lay-out of which will have to be arranged to suit the production flow of several types of vegetable(or alternatively fruit without too much disturbance to the original positioning of the machines, when changing from one product to another The description of the various machines is accompanied by photographs and the brief outline of their function will be amplified in later chapters, which explain more concisely the processing details for a wide range of fruit, vegetables and liquid products It is stressed that some of the preparation plant described will only be required in a medium to large scale operation, because in a low budget project, full automation would be neither viable nor necessary, as such a plant may be able to be used with the simplest product cleaning facilities, peeler, cutter and some simple conveying equipment. Some old established factories in Eastern Europe, specialising in onion dehydration, have operated for years with a minimum of preparation machinery, being convinced that hand peeling of onions, for example, produces a much better product than a
3 Preparation Plant Preparation plant for dehydration is very similar to that used by the canner and freezer, because up to the last stage of conservation the raw material is prepared in similar manner, other than to provide for the introduction of certain additives which are not common to either canned or frozen products. This chapter defines very briefly the type of preparation plant used in a multi-product operation, the lay-out of which will have to be arranged to suit the production flow of several types of vegetable (or alternatively fruit) without too much disturbance to the original positioning of the machines, when changing from one product to another. The description of the various machines is accompanied by photographs and the brief outline of their function will be amplified in later chapters, which explain more concisely the processing details for a wide range of fruit, vegetables and liquid products. It is stressed that some of the preparation plant described will only be required in a medium to large scale operation, because in a low budget project, full automation would be neither viable nor necessary, as such a plant may be able to be used with the simplest product cleaning facilities, a peeler, cutter and some simple conveying equipment. Some old established factories in Eastern Europe, specialising in onion dehydration, have operated for years with a minimum of preparation machinery, being convinced that hand peeling of onions, for example, produces a much better product than a 39
machine and even their cutters have been substantially fabricated in their own workshops. However, as indicated in Table 1. 1.(imports into the UK), the volume produced in this type of factory is very small, and when world prices were low in the 1970 s many Romanian and Bulgarian factories ceased operations in dehydration and reverted to other forms of vegetable and fruit conservation. It is emphasised that the preparation plant described is'upstreamof the dryer Downstream plant is described in the chapteron selection, packing and sto CUT TERS (a) Dicers The dehydration process requires that produce be reduced to a fairly small particle size, otherwise the removalof water becomes an over-extended operation, with consequent damage to the colour, texture, appearance and general quality of the dried product. Also the rehydration 'factor deteriorates Dicers are cutting machines with three separate knife actions (1)a slicing knife positioned in the machines impeller, which rotates at approximately 190rpm, makes the first lateral slice as the product is fed into the machine. The thickness of the slice is adjustable but the maximum dimension is limited by the spacing of (2)the cross-cut knives, which are fixed to a spindle rotating at about 1400rpm. The impeller thrusts the first cut slices on to these cross-cut knives by centrifugal force, making strips ranging from 7 1mm to 13mm in width pre-determined by the thickness of the first slicing cut (3) The third cut is made with a row of circular knives that can be spaced in 3.2mm increments from 6.4 to 76mm apart. Julienne cuts are produced using circular knives spaced 4mm, 4.8mm or mm For this type of cut, the cross-cut knife spindle is replace with a slice guide roll, and the slice thickness(first cut)is djusted to suit the circular knife spacing A Model G dicer can be used as a slicer to produce any thickness up to 19mm. An inner chute must be used in these circumstances to guide slices across the slicing knife holder into the discharge chute The above description, and those given below, relate to one American designed machine, noted for its high performance and reliability, and it is used internationall
machine, and even their cutters have been substantially fabricated in their own workshops. However, as indicated in Table 1 .l. (imports into the UK), the volume produced in this type of factory is very small, and when world prices were low in the 1970‘s many Romanian and Bulgarian factories ceased operations in dehydration and reverted to other forms of vegetable and fruit conservation. It is emphasised that the preparation plant described is ‘upstream’ of the dryer. Downstream plant is described in the chapter on selection, packing and storage. CUTTERS (a) Dicers. The dehydration process requires that produce be reduced to a fairly small particle size, otherwise the removal of water becomes an overextended operation, with consequent damage to the colour, texture, appearance and general quality of the dried product. Also the rehydration ‘factor‘ deteriorates. Dicers are cutting machines with three separate knife actions: (1) a slicing knife positioned in the machine’s impeller, which rotates at approximately 19Orpm, makes the first lateral slice as the product is fed into the machine. The thickness of the slice is adjustable but the maximum dimension is limited by the spacing of (2) the cross-cut knives, which are fixed to a spindle rotating at about 1400rpm. The impeller thrusts the first cut slices on to these cross-cut knives by centrifugal force, making strips ranging from 7.lmm to 13mm in width, pre-determined by the thickness of the first slicing cut. (3) The third cut is made with a row of circular knives that can be spaced in 3.2mm increments from 6.4 to 76mm apart. Julienne cuts are produced using circular knives spaced 4mm, 4.8mm or 6.4mm apart. For this type of cut, the cross-cut knife spindle is replaced with a slice guide roll, and the slice thickness (first cut) is adjusted to suit the circular knife spacing. A Model G dicer can be used as a slicer to produce any thickness up to 19mm. An inner chute must be used in these circumstances to guide slices across the slicing knife holder into the discharge chute. The above description, and those given below, relate to one American designed machine, noted for its high performance and reliability, and it is used internationally. 40
There are other Continental makes built on similar lines, and the processor must judge which marque serves his purpose best in performance The dicer is perhaps the most flexible cutter available, and will handle quite a range of products but, with a wide product mix, other types of cutter will doubtless be needed Cutter knives require constant attention and should be sha every eight hour shift, especially when used on tough vegetables, such as carrots,swedes, turnips, cabbage, celeriac, etc. Failure to do this will give rise to a ragged product which will matt on the drying surface, whether it be a tray or a conveyor slat. This creates an impermeable mass which the air flow will not penetrate, and these conditions will delay drying or, at worst, will make even drying impossible achines are available for both cross-cut knives circular knives and slicing knives, and these can usually be supplied by the cutter manufacturers In a medium to large operation, it is obviously wise to duplicate all cutters, so that by having two in parallel, the knife change will not hold up the production flow and the product can be switched immediately, without any hold-up from one cutter to the stand-by machine. Each knife assembly can be removed with all the knives (ie cross-cut and circular) in situ, and indeed can be sharpened as a unit, without dismantling each knife separately or servicing This facility of course makes it possible for the smaller operator to remove and exchange a knife assembly, so long as he carries a spare assembly, nd in this way he can avoid having to duplicate the whole machine but, of course, there will be some delay in the actual removal of the old machinery and replacement by the spare one, and some production time will be lost The shift fitter must, as a priority, watch the condition of the cutting knives throughout his shift, very much as the seamer fitter in a cannery watches the quality of the double seam cans passing through a high speed can seamer at 1000 cans per minute. In both cases a lapse of attention at this point can spell trouble. Disposable knives avoid honing cost Where cutters are duplicated, it is obviously wise to install two of identical make, so that economy in carrying spare parts is achieved (b)J Cutter This is eminently suitable for bulb and leafy products, such as spinach, leeks, spring cabbage, bell peppers, parsley and other herbs, celery and citrus fruit and the peel The machine operates on the principle of a high speed belt carrying
There are other Continental makes, built on similar lines, and the processor must judge which marque serves his purpose best in performance and cost effectiveness. The dicer is perhaps the most flexible cutter available, and will handle quite a range of products but, with a wide product mix, other types of cutter will doubtless be needed. Cutter knives requk constant attention and should be sharpened every eight hour shift, especially when used on tough vegetables, such as carmts, swedes, turnips, cabbage, celeriac, etc. Failure to do this will give rise to a ragged product which will matt on the drying surface, whether it be a tray or a conveyor slat. This creates an impermeable mass which the air flow will not penetrate, and these conditions will delay drying or, at worst, will make even drying impossible. Honing machines are available for both crosscut knives, circular knives and slicing knives, and these can usually be supplied by the cutter manufacturers. In a medium to large operation, it is obviously wise to duplicate all cutters, so that by having two in parallel, the knife change will not hold up the production flow and the product can be switched immediately, without any hold-up from one cutter to the stand-by machine. Each knife assembly can be removed with all the knives (ie, cross-cut and circular) in situ, and indeed can be sharpened as a unit, without dismantling each knife separately for servicing. This facility of course makes it possible for the smaller operator to remove and exchange a knife assembly, so long as he carries a spare assembly, and in this way he can avoid having to duplicate the whole machine but, of course, there will be some delay in the actual removal of the old machinery and replacement by the spare one, and some production time will be lost. The shift fitter must, as a priority, watch the condition of the cutting knives throughout his shift, very much as the seamer fitter in a cannery watches the quality of the double seam cans passing through a high speed can seamer at lo00 cans per minute. In both cases a lapse of attention at this point can spell trouble. Disposable knives avoid honing costs. Where cutters are duplicated, it is obviously wise to install two of identical make, so that economy in carrying spare parts is achieved. (b) J Cutter This is eminently suitable for bulb and leafy products, such as spinach, leeks, spring cabbage, bell peppers, parsley and other herbs, celery and citrus fruit and the peel. The machine operates on the principle of a high speed belt carrying 41
the product to the cutting parts. A 152mm diameter feed roll is fitted at the feed end of the belt to the knives. This flattens the vegetable before entering the knives and forces them into the cutting area By the arrangement of the circular and cross-cut knives, the j cutter roduces square cuts ranging from 6 by 6mm to 13 by 13mm, the thickness of this square being the thickness of the original product. For example a capsicum with flesh 4mm thick would emerge as a square flake 6 by 6 by 4mm or a larger square if the knives were adjusted. Strip cuts can be made by removing the cross cut knives (c)cc slicer This machine will slice products up to 100mm in diameter. Anything larger will need a heavy duty machine, such as the Model Y slicer, or the G dicer with the cross cut and stripping knives removed The standard slice for the CC slicer is 3. 2mm thick but special parts are supplied to make thicker slices, such as onions at 4mm. One benefit of the CC slicer is that the knives are disposable, and this avoids honing and sharpening and, in effect, these knives are cheaper than the cost of sharpening those fitted to other machines and the cost of down-time. They will operate for 8-12hr with normal usage and are ideal when handling (d)oV Slicer This is a transverse slicer for fruit and vegetables which are not more than 70mm in diameter. Slice thickness is controlled by using a different slicing wheel which can be selected to give a slice length (or thickness ranging from 1.6mm to 32mm The slicer will not handle sticky products but can be used for leeks bananas, carrots,rhubarb, celery and asparagus. The feed must be controlled (e) Comtrol This is a cutter which will produce a wide range of cuts, and will comminute by flaking, slicing, shredding and dicing from 13mm down to microscopic sizes. It handles equally efficiently meat, fish, vegetables and fruit. It would have a special cation in comminuting soup ingredients down to a size suitable for instant or rapid rehydration (f)SC Scarifier This is used in dehydration specifically for slitting the skin or membrane of fresh peas. Peas are normally scarified before blanching, and
the product to the cutting parts. A 152mm diameter feed roll is fitted at the feed end of the belt to the knives. This flattens the vegetable before entering the knives and forces them into the cutting area. By the arrangement of the circular and cross-cut knives, the J cutter produces square cuts ranging from 6 by 6mm to 13 by 13mm, the thickness of this square being the thickness of the original product. For example a capsicum with flesh 4mm thick would emerge as a square flake 6 by 6 by 4mm or a larger square if the knives were adjusted. Strip cuts can be made by removing the cross cut knives. (c) CC Slicer This machine will slice products up to lOOmm in diameter. Anything larger will need a heavy duty machine, such as the Model Y slicer, or the G dicer with the cross cut and stripping knives removed. The standard slice for the CC slicer is 3.2mm thick but special parts are supplied to make thicker slices, such as onions at 4mm. One benefit of the CC slicer is that the knives are disposable, and this avoids honing and sharpening and, in effect, these knives are cheaper than the cost of sharpening those fitted to other machines and the cost of down-time. They will operate for 8-12hr with normal usage and are ideal when handling onions. (d) OV Slicer This is a transverse slicer for fruit and vegetables which are not more than 70mm in diameter. Slice thickness is controlled by using a different slicing wheel which can be selected to give a slice length (or thickness) ranging from 1.6mm to 32mm. The slicer will not handle sticky products but can be used for leeks, bananas, carrots, rhubarb, celery and asparagus. The feed must be controlled very evenly. (e) Comitrol This is a cutter which will produce a wide range of cuts, and will comminute by flaking, slicing, shredding and dicing from 13mm down to microscopic sizes. It handles equally efficiently meat, fish, vegetables and fruit. It would have a special application in comminuting soup ingredients down to a size suitable for instant or rapid rehydration. (f) SC Scarifier This is used in dehydration specifically for slitting the skin or membrane of fresh peas. Peas are normally scarified before blanching, and 42
are fed into the scarifier hopper from which they fall in a controlled stream between a rubber roller and a row of serrated wheels, revolving at a different speed. The peas pass through in a single layer so that each pea makes contact with the slitting wheel. The slit is made at a controlled depth -usually about 3mm as the peas pass between the rubber roller and the knives The purpose of scarifying is fully amplified in the Chapter 5 on the processing of vegetables(green peas) Bean Slicer Model w It is recommended in Chapter 5, on the subject of processing Green Beans, that slicing should be carried out after blanching, to avoid the loss of bean'seed'in the blanching water. Round pod beans are normally used for dehydration,and the Model w slicer gives a Julienne or French-style long cut rather than a transverse cut. the beans are fed by a belt incorporated in the machine to the cutting head, and kept in a straight line by oscillating parallel guides. The head consists of a circular knife spindle, a stripper plate assembly and a stationary knife The beans are cut lengthways by the circular knives, removed from between the knives by the stripper plate and guided on to a horizontal stationary knife at high speed, causing them to be cut through the centre at right angles to the cuts made previously by the circular knives A green bean snibbing line, cluster cutters and spill proof elevator
alp fed into the scarifier hopper from which they fall in a conhdled stream between a rubber roller and a row of serrated wheels, revolving at a different speed. The peas pass through in a single layer so that each pea makes contact with the slitting wheel. The slit is made at a contmlled depth - usually about 3mm as the peas pass between the rubber roller and the knives. The purpose of scarifying is fully amplified in the Chapter 5 on the ptucessing of vegetables (green peas). (g) Bean Slicer Model W It is recommended in Chapter 5, on the subject of processing Green Ekans, that slicing should be carried out after blanching, to avoid the loss of bean 'seed' in the blanching water. Round pod beans are normally used for dehydration, and the Model W slicer gives a Julienne or French-style long cut rather than a transverse cut. The beans alp fed by a belt incorporated in the machine to the cutting head, and kept in a straight line by oscillating parallel guides. The head consists of a circular knife spindle, a stripper plate assembly and a stationary knife. The beans a= cut lengthways by the cirrular knives, removed from between the knives by the stripper plate and guided on to a horizontal stationary knife at high speed, causing them to be cut through the centre at right angles to the cuts made previously by the circular knives. A grm ban snibbing line, cluster cutters and spill proof elevator 43