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Onion & Garlic Dehydration Plants
Specialty Food, Beverage & By-Product Processing

Onion & Garlic Dehydration Plants

An onion and garlic dehydration plant peels, slices and dries bulbs into slices, flakes, granules or powder, and the slice size, dryer and moisture target decide the design.

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Onion & Garlic Dehydration Plants

The feed is cured, undamaged bulbs, so harvest, curing and storage are part of the raw material specification. A buyer should settle the product form first, since flakes, granules and powder need different downstream mills and packing. Next come the moisture target, for powder expressed as water activity, the variety and season of supply, and the heat source. Onion and garlic dry differently: onions are normally dried without blanching, while garlic needs gentle heat to protect its flavour. Both give off a strong sulphur smell, and garlic dust is a workplace hazard, so air handling and dust control are part of the plant, not extras. Capacity is stated in kilograms of wet feed per hour, with the weight lost in peeling and trimming counted in the feed.

Bulbs are topped, peeled and trimmed, washed, and cut into slices of even thickness. Even thickness matters because slices of mixed size dry at different rates, leaving some over-dried and some damp in the same lot. Slices are dried in hot air on a belt or tray dryer, usually in several zones with falling temperature, and then cooled and collected. Garlic is dried at a low temperature because the enzyme that gives its flavour is easily inactivated by heat, so the dryer's temperature limit is a quality parameter, not only a speed setting. Dried slices can be sold whole, flaked, or milled and sieved to granules and powder. Powder is the sensitive product: below a water activity of about 0.4 it does not cake at ambient temperature, above 0.45 caking sets in faster as moisture rises, and anti-caking agents stop working. Hot air can be raised from a steam or hot-water coil, a thermal-oil exchanger or a clean-burning furnace, chosen by local fuel cost. Exhaust must be ducted away and treated for odour.

Indicative Capacity Range

  • 100–5,000 kg wet feed/hour

Key Specification Inputs

Slice size, moisture target, heat source, food hygiene.

Technical Specifications

TechnologyHot-air dehydration of sliced onion and garlic, with optional milling to granules and powder
FeedCured, undamaged bulbs; variety, size and moisture affect dryer loading and smell
Slice ThicknessSet by product form and dryer type, and held constant within one drying lot
Dryer TypeBelt dryer or tray dryer with several temperature zones, chosen by scale and automation level
Garlic Temperature LimitLow drying temperature to protect flavour, set separately from the onion setting
Heat SourceSteam or hot-water coil, thermal oil, or clean-burning furnace, chosen by local fuel cost
Product FormsSlices, flakes, granules or powder, with grades set by sieving
Moisture TargetSet by product form; for powder it is expressed as water activity
Contact MaterialFood-grade stainless steel on belts, trays, chutes and mills that touch product
Air and Dust HandlingExhaust ducting with odour treatment, plus dust extraction and bag filters on the mill and pack-off
UtilitiesWash water, a heat source, electric power and a route for peels, trimmings and effluent

Typical Process Route

1

Receiving and checking bulbs

Bulbs are sorted for curing, damage and size on arrival. Well-cured bulbs with sound outer scales dry and store better, so poor material should be rejected before it enters the plant.

2

Topping, peeling and trimming

Tops and roots are cut, and the dry skin is removed by abrasive or air peeling. For garlic, cloves are first separated from the head. Excess trimming wastes feed, and too little leaves skin in the product.

3

Washing and draining

Peeled bulbs or cloves are washed to remove grit and drained so that surface water does not load the dryer.

4

Slicing to even thickness

A slicer cuts to a set thickness, and a screen or grader removes ends and fines. Slices of one thickness dry together, so slicer sharpness and setting are checked often.

5

Hot-air drying

Slices are spread on a belt or trays and dried in hot air, with temperature falling as moisture drops. Garlic must stay within a low temperature limit, and onion is dried without a blanching step.

6

Moisture measurement

Moisture is measured on the dried product, with water activity checked for anything to be milled to powder. Over-dried slices waste energy, and damp ones cake or spoil in the pack.

7

Cooling and collection

Dried slices are cooled before handling, because warm product packed in a sealed bag releases moisture and clumps. They are collected from the dryer by conveyor.

8

Milling, sieving and grading

For granules and powder, dried slices go through a mill and sieves into sized grades. This area makes dust and needs extraction, particularly for garlic.

9

Hygienic packing

Product is packed in moisture-proof liners and sealed in a dry, clean room. Onion and garlic powders take up moisture quickly, so the pack barrier is part of the product specification.

Process & Equipment Modules

  • Bulb cleaner and topping station
  • Abrasive or air peeler
  • Washer and draining conveyor
  • Slicer with adjustable thickness
  • Slice grading screen
  • Belt or tray dryer
  • Hot-air generator or heating coil
  • Cooling section and product conveyor
  • Mill and sieve set for granules and powder
  • Dust extraction and bag filter
  • Moisture and water-activity meters
  • Packing station with moisture-proof liners

Plant Output

Dried onion slices and flakesDried garlic slices and flakesOnion and garlic granules and powderPeels and trimmings for compost or feed

Applications

  • Dehydrated onion flakes for soups, sauces and instant noodles
  • Onion powder for seasoning blends and snack coatings
  • Garlic flakes and granules for sauces and ready meals
  • Garlic powder for spice mixes and meat seasonings
  • Onion and garlic pieces for bouillon and dry soup bases
  • Bulk dried ingredient for food manufacturers and export
  • Onion and garlic powder as a base for seasoning sachets

Key Features

  • Even Slice Thickness

    A slicer that holds its setting, followed by sorting of cut pieces, makes dryer performance uniform from the first belt to the last.

  • Low Temperature for Garlic

    A dryer with a controlled temperature ceiling protects the flavour enzyme in garlic, so the control range matters more than the top speed.

  • Water-Activity Control for Powder

    Onion powder keeps without lumping only if its final moisture is held below a set water activity, which is measured, not guessed.

  • Odour and Exhaust Handling

    Strong sulphur compounds leave with the exhaust air, so ducting and treatment are laid out so that smell does not reach neighbours or other products.

  • Dust Extraction in Milling

    Garlic powder and dust can cause allergic reactions, including asthma, in workers, so the mill and packing area need extraction and operator protection.

Country Pages for Onion & Garlic Dehydration Plants

This product is listed on the pages of the countries below, each with its own enquiry route. Where Kadali has no office in a country, enquiries are handled from the Accra office.

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Frequently Asked Questions

What information is needed to size Onion & Garlic Dehydration Plants?
The kilograms of fresh bulbs per hour and the hours of operation, the share of onion and garlic, the product form (slices, flakes, granules or powder) and the moisture or water activity wanted. Also give the heat source and its cost, how long the season of supply runs, and whether the bulbs are peeled by the plant or bought pre-peeled.
What capacity range does Onion & Garlic Dehydration Plants cover?
The indicative capacity range is 100–5,000 kg wet feed/hour. It is stated on a wet feed basis per hour, so restate your own volume on that basis and say how many hours a day the plant will run.
Do onions need blanching before they go into the dryer?
Onions are normally dried without blanching, unlike green beans, carrots, okra and cabbage. For an onion line this means no blanching stage is needed in the basic design, though a customer's specification may ask for other preparation steps. Ask the proposal to show what happens between slicing and the dryer so that no unneeded step is added.
Why is garlic dried at a lower temperature than onion?
Garlic's flavour depends on an enzyme that is released when cloves are crushed, chopped or chewed. Heat can inactivate it, so garlic slices are dried at a low temperature. The dryer's temperature limit is therefore a quality control for garlic. If one dryer will process both crops, check that it can run at two separate temperature settings and be cleaned in between.
Are preservatives such as sulphite normally added when drying onion and garlic?
As a general rule preservatives are not used on onions, garlic, leeks, chillies and herbs, even though many other fruits and vegetables are treated to hold their colour. The treatment depends on the product specification and the customer's requirements, so confirm them with the buyer of the powder or flakes before the process is fixed.
Can an anti-caking agent fix lumpy onion powder?
Not at higher moisture. Caking did not occur at ambient temperature below a water activity of about 0.4, while above 0.45 the time to caking shortened as water activity rose and anti-caking agents were completely ineffective. Control of the moisture in the powder, through the dryer end point and the pack barrier, is therefore the control that works.
How should dust and smell be handled?
Onion and garlic release strong sulphur compounds that can travel and taint other products, so exhaust air needs ducting and odour treatment. Garlic dust can trigger allergic reactions, including asthma, in workers who handle the powder. Put dust extraction, bag filters and operator protection on the milling and packing area, and keep it separate from other food lines.
Which dryer suits an onion and garlic line?
A multi-zone belt dryer is the usual choice for slices at industrial scale because it gives continuous flow and even air contact, while tray dryers suit small and seasonal operations. Where the same hot-air dryer also dries other vegetables, see industrial hot-air drying systems and fruit and vegetable dehydration plants.
How do I request a proposal for Onion & Garlic Dehydration Plants?
Use the Request a Quote page and describe your project. State the product form (slices, flakes, granules or powder), the moisture and colour you need, the produce supply and the volumes.

Enquire about Onion & Garlic Dehydration Plants

Send your raw material, target product and capacity to Kadali Africa Ventures for a technical proposal.

Request a QuoteWhatsApp