6 hydration of Vegetables The vegetable cultivars quoted in the following process data are, in the main, those bred in temperate climates, the USA and Western Europe and, in the case of pulses, the Antipodes. However, with the growth of dehydration in the developing countries, with tropicalorsubtropicalclimates, theseregions, along with Eastern Europe, Egypt and China, who have had a dehydration industry for many years, have, through their Horticultural Institutes and Ministries of Agriculture, developed indigenous varieties which have been processed with considerable success It may not be possible to identify all these varieties but in the author experience, great assistance has been afforded by the field officers working with these Horticultural Institutes in setting up field and seed trials for the benefit of processors, and they are becoming increasingly knowledgeable in the characteristics required in vegetables for processing uiredy have afforded, also, valuable in formation on the infrastructure required for setting up a processing plant, along with the disposition of labour, local building requirements for food factories and the pattern of irrigation practice e processes set out assume an intermediate size operation with a reasonable measure of automation but, of course, in each case the throughput may be cut down to meet capital budgeting requirements, and whilst most of the preparation plant is geared to a raw throughput of some 1.5 to 3 tonnes per hour of prepared material or 300 to 350 tonnes of raw produce per week, adjustments can obviously be made, introducing more hand labour
6 Dehydration of Vege ta b I es The vegetable cultivars quoted in the following process data are, in the main, those bred in temperate climates, the USA and Western Europe and, in the case of pulses, the Antipodes. However, with the growth of dehydration in the developing countries, with tropical or subtropicalclimates, these regions, along with Eastern Europe, Egypt and China, who have had a dehydration industry for many years, have, through their Horticultural Institutes and Ministries of Agriculture, developed indigenous varieties which have been processed with considerable success. It may not be possible to identify all these varieties but in the author’s experience, great assistance has been afforded by the field officers working with these Horticultural Institutes in setting up field and seed trials for the benefit of processors, and they are becoming increasingly knowledgeable in the characteristics required in vegetables for processing. They have afforded, also, valuable information on the infrastructure required for setting up a processing plant, along with the disposition of labour, local building requirements for food factories and the pattern of irrigation practices. The processes set out assume an intermediate size operation with a reasonable measure of automation but, of course, in each case the throughput may be cut down to meet capital budgeting requirements, and whilst most of the preparation plant is geared to a raw throughput of some 1.5 to 3 tonnes per hour of prepared material or 300 to 350 tonnes of raw produce per week, adjustments can obviously be made, introducing more hand labour in 121
preparation and using Stove or Through-Flow Tray Dryers instead of a Conveyor Band Dryer, either single or multi-pass Whilst a product-mix should be arrived at to give the maximum numberof days workin a season, it is wise toconcentrate on those vegetables which are available for several months of the year, either from seasonal sowings, or by having storage facilities at the factory or farm. Too many change-overs from product to product are costly, often entailing moving plantaround, but what is moreimportant is knowing the market demand for those vegetables for which the climate and growing conditions are ideal HORTICULTURE It is difficult to guide the processor in horticultural procedures, as climate and soil conditions will vary considerably from region to region. The company agronomist must assess all the requirements and problems on the spot, and in a new venture it is absolutely essential to carry out field trials for every vegetable to be processed. However the author has appended some horticultural guide lines for seven of the more popular vegetables grown for dehydration, and these follow the processing data in this chapter he guide lines are based on actual field trials and commercial scale cultivation in several locations varying from temperate to subtropical limatic conditions. In most cases irrigation was available, either contour or GREEN BEANS (1)Flow -Sheet Feed to Line P Cluster Cutting(only for machine harvested beans) tie Snipping Blanching
preparation and using Stove or Through-Flow Tray Dryers instead of a Conveyor Band Dryer, either single or multi-pass. Whilst a product-mix should be arrived at to give the maximum number of days work in a season, it is wise to concentrate on those vegetables which are available for several months of the year, either from seasonal sowings, or by having storage facilities at the factory or farm. Too many change-overs from product to product are costly, often entailing moving plant around, but what is more important is knowing the market demand for those vegetables for which the climate and growing conditions are ideal. HORTICULTURE It is difficult to guide the processor in horticultural procedures, as climate and soil conditions will vary considerably from region to region. The company agronomist must assess all the requirements and problems on the spot, and in a new venture it is absolutely essential to carry out field trials for every vegetable to be processed. However, the author has appended some horticultural guide lines for seven of the more popular vegetables grown for dehydration, and these follow the processing data in this chapter. The guide lines are based on actual field trials and commercial scale cultivation in several locations varying from temperate to subtropical climatic conditions. In most cases irrigation was available, either contour or overhead spray. GREEN BEANS (1) Flow-Sheet Feed to Line I Pneumatic Separator I Washing I Cluster Cutting (only for machine harvested beans) I Inspection I Snipping I Inspec tion I Blanching I22
Sulphating Slicing (long cut Dewatering Drying onditioning reening Inspection (2)Varieties Tendergreen, Processor, Bush Blue Lake (3)Product Handling The bean pods are either harvested by hand or, in the case of large acreages, by mobile bean harvesters. They are fed to the line in a bulk feeder from where the po delivered into a pneumatic separator to remove extraneous matter They are then transferred to a reel washer which, in the case of machine harvested beans, feeds in to cluster cutters, to 'single any beans not separated from their stalks in the harvester. This machine is not necessary for hand harvested beans After inspection on a conveyor belt, the beans are conveyed on a vibratory trough belt and ploughed off into a battery of shippers. The numberof snipers willdepend on throughput, as each machine will handle about 1000kg per hour. At the exit end of each snipper an unshipped bear removal reel takes care of any beans not topped and tailed and returns them to the snippets Snipped beans are then visually inspected on a conveyor belt and delivered into the blancher. This can be either a hot water or steam type, depending on what other products are to be catered for. For example, if cabbage or leaf vegetables are included in the product mix, it would be d visable to opt for steam blanching as this is more suitable for brassicas. Sulphiting is effected by pumping from sulphite make-up pans into the blanching water, in the case of hot water blanching. If steam blanching is
I Sulphiting I Slicing (long cut) I Dewatering I Drying I Conditioning I Screening I Inspection I Packing (2) Varieties (3) Product Handling The bean pods are either harvested by hand or, in the case of large acreages, by mobile bean harvesters. They are fed to the line in a bulk feeder from where the pods are delivered into a pneumatic separator to remove extraneous matter. They are then transferred to a reel washer which, in the case of machine harvested beans, feeds in to cluster cutters, to 'single' any beans not separated from their stalks in the harvester. This machine is not necessary for hand harvested beans. After inspection on a conveyor belt, the beans are conveyed on a vibratory trough belt and ploughed off into a battery of snippers. The number of snippers willdepend on throughput,as each machine will handle about lOOOkg per hour. At the exit end of each snipper an unsnipped bean removal reel takes care of any beans not topped and tailed and returns them to the snippers. Snipped beans are then visually inspected on a conveyor belt and delivered into the blancher. This can be either a hot water or steam type, depending on what other products are to be catered for. For example, if cabbage or leaf vegetables are included in the product mix, it would be advisable to opt for steam blanching as this is more suitable for brassicas. Sulphiting is effected by pumping from sulphite make-up pans into the blanching water, in the case of hot water blanching. If steam blanching is Tendergreen, Processor, Bush Blue Lake I23
used, sulphiting is carried out in a sulphite dip tank situated at the discharge end of the blancher, and the solution of sodium sulphite is made up in the pans alongside. Anhydrous sodium sulphite is always used for green vegetables and sodium metabisulphite forroot vegetables, where sulphiting is permitted under prevailing Food Laws Whole beans are fed on a vibratory conveyor to slicing machines(long cut)with a capacity of 2000kg per hour each, the slicing taking place after blanching to prevent theseed of the pod being washed away in theblanching roces pr After dewatering, the cut beans pass into the dryer, thence to conditioning bins The dried slices are elevated to the screen for sifting to remove broken pieces and fines, and then to the final inspection tables acking should be in poly-lined cartons or drums, rather than paper bags, to avoid breakage Conveyor Band dryer scaled to throughput Temperatures(input): 85/77/60C Conditioning:50·52℃ CRy to6% Overall ratio: 13.1 Drying ratio: 9.1 Cultivation Guidelines for Geen Beans (1)Sowing: oOkg per Ha. Sow in singlerow 7.5-10cm apartat4lcm centres Sow 50mm 2)Fertilisers. On irrigated land use N40/P80/K60 plus 2.5 tonnes of organic per Ha., if 3)Herbicides Preforan or gramoxone or Dachtal (4)Pesticides. Dimethoate or Diazinon; for caterpillar attack, use Folithon or Diazinon 5) Disease Control Botrilex against Southern Blight or Root Rot Afucan or Benlate every 7 days against powdery mildew Kocide, Perenox or Cupravit against bacterial blight or rust (6)Maturity Pick every second day to avoid over-maturity 8mm is the maximum pod diameter (measured across a section of the bean)fo t processIn Harvest is about 60-70 days from sowing Plant population: 430,000 per Ha
used, sulphiting is carried out in a sulphite dip tank situated at the discharge end of the blancher, and the solution of sodium sulphite is made up in the pans alongside. Anhydrous sodium sulphite is always used for green vegetables and sodium metabisulphite for root vegetables, where sulphiting is permitted under prevailing Food Laws. Whole beans are fed on a vibratory conveyor to slicing machines (long cut) with a capacity of 2000kg per hour each, the slicing taking place after blanching to prevent the seed of the pod being washed away in the blanching process. After dewatering, the cut beans pass into the dryer, thence to conditioning bins. The dried slices are elevated to the screen for sifting to remove broken pieces and fines, and then to the final inspection tables. Packing should be in poly-lined cartons or drums, rather than paper bags, to avoid breakage. (4) Drying Conveyor Band dryer scaled to throughput Temperatures (input): 85"/ 77"/ 60°C Conditioning: 5Oo-52"C Dry to 6% Overall ratio: 13.1 Drying ratio: 9.1 Cultivation Guidelines for Geen Beans (1) Sowing: 150kgperHa. Sowinsinglerows7.5-lOcmapartat4lcmcentres. Sow50mm deep in fine tilth. (2) Fertilisers. On irrigated land use N40/P80/K60 plus 2.5 tonnes of organic per Ha., if available. (3) Herbicides. Preforan or Granoxone or Dachtal. (4) Pesticides. Dimethoate or Diazinon; for caterpillar attack, use Folithon or Diazinon. (5) Disease Control. Botrilex against Southern Blight or Root Rot. Afucan or Benlate every 7 days against powdery mildew. Kocide, Perenox or Cupravit against bacterial blight or rust. (6) Maturity Pick every second day to avoid over-maturity. 8mm is the maximum pod diameter (measured across a section of the bean) for processing. Harvest is about 60-70 days from sowing. Plant population: 430,000 per Ha. I 24
BEETROOT (1)Flow-Sheet emi-Continuous Process Feed to Line Destoner-Washer Batch process Autoclave cooking emi-Continuous Pressure Cooking Washing Skin removal Inspection Cutting Dewatering Drying Conditioning Screening Inspection acking Detroit Red Globe (3)Product Handling cut off) at the farm. Care must be taken to avoid bruising and bleedin i Beets should be selected 50-75mm in diameter, with the tops wrung off(n From the bulk feeder they pass through a dry cleaning plant to remove soil, then to a destoner-washer or alternatively a flood washer, if free of stones Two options are open to the processor: (a)to feed the beets into a batch thermoscrew operating at 1. 2atm steam pressure. A Thermoscrew 6m long by Im diameter should batch-cook young beets in a 20-40 minute cycle at a
BEETROOT (1) Flow-Sheet Semi - Continuous Process I Feed to Line a I Autoclave cooking Destoner-Washer Batch Process Semi-Continuous Pressure Cooking Skin Washing Removal 2 I Inspection I Cutting I Dewatering I Drying I Conditioning I Screening I Inspection I Packing (2) Varieties (3) Product Handling Beets should be selected 50-75mm in diameter, with the tops wrung off (not cut off) at the farm. Care must be taken to avoid bruising and 'bleeding'. From the bulk feeder they pass through a dry cleaning plant to remove soil, then to a destoner-washer or alternatively a flood washer, if free of stones. Two options are open to the processor: (a) to feed the beets into a batch thermoscrew operating at 1.2atm steam pressure. A Thermoscrew 6m long by lm diameter should batch-cook young beets in a 20-40 minute cycle at a Detroit Red Globe I25