Introduction
Bromelain (CAS 9001-00-7) is a proteolytic enzyme preparation obtained from the pineapple plant (Ananas comosus). It is a mixture of cysteine proteases that hydrolyse peptide bonds in proteins, releasing smaller peptides and amino acids. Because bromelain is a biological product rather than a single small molecule, it is not described by a molecular formula or a SMILES string: instead it is specified and traded by its enzymatic activity, most commonly in GDU/g (gelatin digesting units per gram). Commercial bromelain is used in food processing, nutrition and dietary supplements, cosmetics and several industrial processes.
Chemical and Physical Properties
Bromelain is a complex of several proteases, dominated by stem bromelain (EC 3.4.22.32) and fruit bromelain (EC 3.4.22.33). The individual enzyme components have molecular weights in the roughly 20-50 kDa range and share a cysteine (thiol) active site, which is why reducing agents and heavy-metal ions can affect their activity.
| Property | Value |
|---|---|
| CAS number | 9001-00-7 |
| EC number (stem bromelain) | 3.4.22.32 |
| Product type | Proteolytic enzyme preparation (mixture) |
| Appearance | Light yellow powder |
| Odour | Light pineapple smell |
| Active site | Cysteine (thiol) protease |
| pH range for activity | About 4.5 to 8.0 |
| Temperature range for activity | About 45 to 55 C, with loss of activity above about 60 C |
| Typical activity unit | GDU/g (gelatin digesting units per gram) |
Because enzymes are proteins, their activity – not a melting point or a molecular formula – is the defining property. Prolonged heat or extreme pH denatures the enzyme irreversibly and drives the activity down, so temperature and pH are the most important variables in storage and in process design.
Enzymatic Activity and How It Is Measured
The commercial value of bromelain is set by its activity, which is measured by a standardised assay rather than by mass. The most widely used unit is the GDU (gelatin digesting unit): a defined amount of enzyme is allowed to digest a gelatin substrate under controlled conditions, and the activity is reported as GDU per gram. Buyers also meet other units in the market, such as the milk-clotting unit (mcu) and the FCC papain unit (PU).
Two practical points follow from this:
- Activity is not the same as purity. A material can be “pure” by protein content and still have low enzymatic activity if it has been partly denatured.
- Standardisation matters. Manufacturers blend batches to a target activity, so that a grade such as 2400 GDU/g behaves consistently from lot to lot.
Production Process
Bromelain is recovered from pineapple material and then purified and standardised. The pineapple stem is the usual industrial source because it carries a high concentration of the enzymes.
1. Harvesting and preparation
Mature pineapple stems are collected, separated from the fruit and washed to remove surface contaminants before processing.
2. Extraction
The stems are ground or mashed to break down the plant cell structure, and the soluble enzymes are extracted into a buffered aqueous solution. Mild warming (kept well below the denaturation temperature) can improve recovery.
3. Purification
The extract is clarified by filtration, centrifugation or ultrafiltration to remove plant debris and large particulates, and the protease fraction is then purified by techniques such as ion-exchange or affinity chromatography.
4. Concentration, standardisation and drying
The purified concentrate is concentrated (for example by vacuum evaporation or freeze-drying) and dried to a powder. The powder is then standardised to the target GDU activity and packed, so that each batch meets the agreed specification.
Applications
Bromelain’s ability to hydrolyse proteins under mild conditions is the basis of its use across several industries.
Food processing
Bromelain is used to hydrolyse and tenderise proteins in meat processing and in pre-marinated products, where controlled proteolysis improves texture. It is also used in protein hydrolysate production and in some beverage and juice applications.
Nutrition and dietary supplements
As a digestive enzyme, bromelain is formulated into enzyme supplements and blends, where the product is standardised on activity (for example 2400 GDU/g) and combined with other proteases and excipients.
Pharmaceutical and medical
Bromelain has a long history of investigation for its anti-inflammatory and related properties. It is studied in the context of swelling and inflammation management and wound care. As with any active material, claims must be supported by appropriate evidence and handled in line with applicable pharmaceutical and nutraceutical regulations; this article does not make medical claims.
Cosmetics and personal care
In cosmetics, bromelain is used for its mild exfoliating action, helping to break down protein components of dead skin cells, and in skin-soothing formulations. It appears in masks, peels and after-sun products.
Textile and biotechnology
In textiles, proteases such as bromelain are applied in bio-finishing to soften natural fibres and to help remove protein stains, offering a milder alternative to aggressive chemistry. In biotechnology it is studied as a biocatalyst and in the treatment of protein-rich waste streams.
Quality, Grades and Specifications
Bromelain is bought against a specification that combines activity with microbiological and heavy-metal limits. The grade below is typical of a 2400 GDU/g food-grade material.
| Parameter | Specification |
|---|---|
| Appearance | Light yellow color |
| Odor | Light pineapple smell |
| Activity (GDU/g) | ≥2400 |
| Moisture (%) | ≤8 |
| Mesh (%) | 100% pass 80 mesh |
| Pb (mg/kg) | ≤5 |
| As (mg/kg) | ≤3 |
| Total plate count (CFU/g) | ≤10000 |
| Salmonella (25g) | Absent |
| E. coli (MPN/g) | Absent |
| Coliform group (MPN/g) | ≤30 |
| Molds & Yeasts (CFU/g) | ≤100 |
The activity value is the headline parameter; the microbiological and heavy-metal limits decide whether the material is suitable for food, supplement or cosmetic use. More detail on units, grades and quality control is covered in the companion article on bromelain activity and grades, and the commercial side is covered in the bromelain buying guide.
Handling, Storage and Stability
Bromelain is a protein, so it must be protected from the conditions that denature enzymes:
- Store cool, dry and tightly sealed, away from heat and humidity.
- Keep it within the recommended temperature and pH range; avoid prolonged exposure above about 60 C.
- Limit dust and follow the safety data sheet for personal protective equipment, since enzyme powders can be respiratory sensitisers.
- Use material within its shelf life and re-check activity if storage conditions were not controlled.
Frequently Asked Questions about Bromelain
What is bromelain?
Bromelain (CAS 9001-00-7) is a proteolytic enzyme preparation from pineapple, supplied as a light yellow powder standardised on activity.
Is bromelain a single chemical compound?
No. It is a mixture of cysteine proteases, which is why it has no single molecular formula or SMILES and is specified by enzymatic activity (for example GDU/g).
What does GDU/g mean?
GDU/g stands for gelatin digesting units per gram; it is a standardised measure of how much protein the enzyme can hydrolyse under defined assay conditions.
How should bromelain be stored?
Cool, dry and tightly sealed, away from heat and humidity, and within the recommended temperature and pH range to avoid loss of activity.
Where can I buy bromelain?
PolyBlueChem supplies bromelain (CAS 9001-00-7) with COA and MSDS. Contact our team for specifications, packaging and a quotation.
References
- PubChem and enzyme database entries for bromelain (CAS 9001-00-7), including EC 3.4.22.32.
- Manufacturer specification sheets for food-grade bromelain standardised at 2400 GDU/g.
- General reference material on proteolytic enzymes and enzyme activity units.
Disclaimer: This article is provided for general informational purposes only and does not constitute technical, medical, regulatory or safety advice. Always refer to the current safety data sheet and applicable regulations before handling or using this material.
PolyBlueChem, as the chemical supplier of all categories, is the supplier of bromelain (CAS 9001-00-7) as well. Contact our team for specifications, packaging and a quotation.