Natural Colour Extraction Plants

Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage

Mechotech designs and manufactures turnkey natural colour extraction plants for purple vegetables. In the Mechotech catalogue, Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage is the entry of the Purple Colour group. According to Mechotech’s article on purple colour extraction from vegetables, all four are coloured by anthocyanins, water-soluble flavonoid pigments based on the flavylium ion that appear red in strong acid, purple to violet at mildly acidic to neutral pH and blue under alkaline conditions. The article names cyanidin and peonidin types, much of them acylated, in purple sweet potato and purple potato, cyanidin-based anthocyanins in purple corn kernels and cobs, and a broad set of cyanidin glycosides in red cabbage that shift colour dramatically with pH. The entry lists four raw materials, so the feed and the target shade are confirmed with the client.

Mechotech’s purple vegetables plant is configured around the raw material and the target colour extract. It is built in SS 316L with integrated solvent recovery, automation and full documentation, and is delivered as a commissioned turnkey system. The article describes chopped or pulped vegetable steeped in mildly acidified water or aqueous ethanol (often with a little citric acid), gentle rather than harsh heat, filtration or centrifugation, concentration, and stabilisation by acidic pH around 3 to 5, antioxidant additives and freeze-drying or microencapsulation. The raw material, solvent and conditions for a project are established during process development and pilot validation.

Technical Specifications

Product	Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage Natural Colour Extraction Plant
Raw Material	Purple sweet potato, purple potato, purple corn and red cabbage (catalogue name: Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage)
Botanical Name	Not stated in the product tree; the article names the vegetables by common name only
Plant Part / Feed Form	Tubers (purple sweet potato, purple potato), kernels and cobs (purple corn) and red cabbage, as the article describes them; chopped or pulped before extraction; the exact feed and form are confirmed with the client
Colour Group	Purple Colour (see the Purple Colour page)
Colour-forming Components	Anthocyanins (cyanidin, peonidin and related glycosides, often acylated), pH-sensitive and prone to degradation by heat, light and oxygen; acylated anthocyanins are more stable (per the article)
Process Category	Natural Colour Extraction Plants
Extract Type	Natural colour extract (liquid concentrate or dried powder, per specification)
Extraction Method	Extraction with mildly acidified water or aqueous ethanol in closed jacketed SS 316L vessels at gentle temperature (per the article), then concentration and stabilisation; route confirmed during process development
Product-contact Material	SS 316L
Filtration System	Plate-and-frame filter press with cartridge polish filters
Concentration System	Falling-film / vacuum evaporator with solvent recovery where a solvent is used
Drying System	Spray or vacuum dryer, where a powder is required
Automation	PLC-based
Plant Capacity	Configured to requirement
Utility Requirements	Steam, chilled/cooling water, compressed air and power (project-specific)
Compliance	GMP hygienic design; full documentation for qualification
Final Product Form	Natural colour extract (purple colour group)

Plant Capacities

Plant Scale	Raw Material Throughput	Typical Use
Pilot	Configured to your feedstock and trial plan	Product development, parameter validation
Semi-Commercial	Configured between pilot and commercial scale	Scale-up trials, contract manufacturing
Commercial	Configured to raw-material supply and confirmed buyer volume	Commercial production

Capacity is configured to raw-material supply, confirmed buyer volume and investment timeline; a pilot plant is recommended to validate parameters before scaling.

Manufacturing Process

Raw Material Preparation

The chosen vegetable is authenticated, cleaned, tested for moisture and chopped or pulped so the solvent can reach the tissue; the article names purple sweet potato as a leading commercial source and notes that acylated-rich sources resist fading better.

Extraction

The vegetable is steeped in mildly acidified water or aqueous ethanol, often with a little citric acid, which the article says keeps the pigment in its stable red-purple flavylium form and improves yield. Gentle rather than harsh heat is used because anthocyanins degrade when overheated; the solvent and temperature are set during process development.

Filtration

The liquor is filtered or centrifuged to remove solids, through a plate-and-frame filter press and cartridge polish filters.

Concentration & Solvent Recovery

The clarified extract is concentrated in a falling-film / vacuum evaporator, with solvent recovered through the condenser return system where ethanol is used.

Standardisation & Stabilisation

Colour strength is standardised, and the article names the stabilising controls: acidic conditions around pH 3 to 5 held through processing and in the final product, and antioxidant additives such as citric acid or ascorbic acid.

Drying & Quality Control

The extract is supplied as a liquid concentrate or converted by freeze-drying or microencapsulation into a dry powder that the article says protects the pigment from moisture, light and oxygen, then released after assay, residual-solvent (where ethanol is used), heavy-metal, microbial and moisture testing.

Major Plant Equipment

Vegetable cleaning, chopping and pulping system
Closed jacketed SS 316L extraction vessels
Acid (citric acid) dosing and pH-control system
Solvent storage tanks (ethanol, where used)
Plate-and-frame filter press or centrifuge
Cartridge polish filtration
Falling-film / vacuum evaporator
Solvent recovery unit and condensers
Standardisation / blending vessel
Spray dryer, freeze dryer or microencapsulation unit
CIP system
Automation and instrumentation

Plant Output

Natural colour extract (purple colour group), as a liquid concentrate or dried powder per specification

Applications

Clean-label natural purple and red-purple colour for food and beverage (per the article)
Cosmetic natural colour (per the article)
Textile dyeing of wool, cotton and silk with alum, copper sulphate or iron sulphate mordants (per the article)
Pharmaceutical use of anthocyanin extracts (per the article)

Key Features

SS 316L Construction
Electropolished SS 316L product-contact surfaces with CIP operation between batches.
Acidified Anthocyanin Route
The plant follows the article’s mildly acidified water or aqueous ethanol extraction, which keeps anthocyanins in their stable form.
pH-Controlled Stabilisation
Acidic processing around pH 3 to 5, antioxidant additives and freeze-drying or microencapsulation are the stabilising steps the article names.
Four Sources, One Colour Family
Purple sweet potato, purple potato, purple corn and red cabbage share the anthocyanin family but differ in base hue and stability, so the source is chosen with the client.
Scalable Batch Capacity
Plants are configured to requirement from pilot scale upward, with modular expansion.

Frequently Asked Questions

Does Mechotech supply the complete machinery for Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage?

Yes. Mechotech supplies the complete turnkey plant for Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage — engineered, fabricated at our Hyderabad facility, installed and commissioned as a single integrated system. Final process parameters are established during process development and pilot validation.

What specification can the Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage plant achieve?

The plant is configured to the client’s target specification for Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage; the specification achieved is established during process development and pilot validation, and batch-release testing with certificate-of-analysis documentation is defined with the client.

What production capacities are available for the Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage plant?

Capacity for the Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage plant is configured to raw-material supply, confirmed buyer volume and investment timeline, starting at pilot scale; a pilot plant is recommended to validate parameters before scaling.

Which industries use the Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage plant?

The end-use areas listed for Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage are given under Applications. The end use, the colour shade and the target specification are confirmed with the client before the plant is configured.

Which vegetables and which parts are covered?

The catalogue entry combines four raw materials: purple sweet potato, purple potato, purple corn and red cabbage. Mechotech’s article describes tubers, purple corn kernels and cobs, and red cabbage, without a plant part for the cabbage. The raw material to be processed and its form are confirmed with the client before the plant is configured.

What pigment makes these vegetables purple?

According to the article, anthocyanins, water-soluble flavonoid pigments built on the flavylium cation, as glycosides of anthocyanidins such as cyanidin, peonidin, delphinidin and pelargonidin, often acylated with organic acids. Read more in Purple Colour Extraction from Vegetables.

Why does the colour change with pH?

The article says anthocyanins appear red in strong acid, purple to violet at mildly acidic to neutral pH and blue to blue-green under alkaline conditions, which is both their signature and their main formulation challenge. The target shade and pH window for a product are set in application trials.

How is anthocyanin purple kept from fading?

The article names acidic conditions around pH 3 to 5, antioxidant and preservative additives such as citric acid, ascorbic acid or sodium benzoate, and freeze-drying or microencapsulation to protect the pigment from moisture, light and oxygen. The stabilising steps for a project are set during process development.

Can anthocyanin extracts dye fabric?

The article says metal mordants such as alum, copper sulphate and iron sulphate fix the pigment on the fabric and can shift and deepen the hue, improving wash- and light-fastness on wool, cotton and silk. This describes dyeing; the extract specification for a product is agreed with the buyer.

How does this page differ from the red vegetable page and the other sweet potato pages?

Red cabbage also appears on Vegetables - Raddish / Red Cabbage / Strawberry / Beetroot in the Red Colour group, so the two entries overlap on that vegetable. Mechotech’s Sweet Potato Orange Flesh Beta-Carotene Extract and Sweet Potato Tuber Starch Extract are separate extraction products with other targets. Confirm which raw material and target are wanted.

Where does this page sit in the Purple Colour range?

Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage is part of the Purple Colour group (hub page: Purple Colour); the product tree lists it as the only entry in that group. The overall catalogue hub is Natural Colour Extraction Plants.

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Vegetables - Purple sweet Potato / Purple potato / Purple corn / Red Cabbage