Acetylated Starch
Acetylated starch, also called starch acetate or mono starch acetate, is a starch in which a small proportion of the hydroxyl groups on the glucose units have been esterified with acetic acid. Only a low degree of substitution is used in food, typically well under one acetyl group per hundred glucose units, so the material remains a starch in composition and is digested as one.
The bulky acetyl groups act as spacers between starch chains. They weaken the hydrogen bonding that holds the granule together, so gelatinisation begins at a lower temperature and the granule swells more readily, and they physically obstruct the re association of amylose and amylopectin chains as a cooked paste cools. That second effect is the commercial point of the modification: an acetylated starch paste stays clear, smooth and fluid where a native starch paste would cloud, firm up and release water during chilled or frozen storage. Freeze thaw stability is markedly improved for the same reason.
What acetylation does not provide is mechanical strength. The granule is not cross linked, so it still ruptures under retort temperature, prolonged high shear or strong acid, and viscosity falls away when it does. Acetylated starch is therefore used where storage stability matters and process severity is moderate; where both are severe, a dual modified acetylated distarch phosphate or adipate is used instead. The material comes as a white to off white free flowing powder, and as a pregelatinised instant powder for cold water use.
We source bulk Acetylated Starch from top China manufacturers for our partners, working with several of them. The manufacturers are in Jiangsu, Shandong and Zhejiang. A smaller requirement can ship in a combined container with other ingredients.
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- Function
- Texturisers
Specifications
| Item | Specification |
|---|---|
| Appearance | White to off white free flowing powder, free of foreign matter |
| Odour and taste | Bland, no vinegar or off odour |
| Identification | Iodine stain and granule microscopy conform to starch reference |
| Total starch, dry basis | 97.0 percent minimum |
| Acetyl groups | 2.5 percent maximum |
| Free acetic acid | 0.1 percent maximum |
| Residual vinyl acetate | 0.1 mg/kg maximum |
| Moisture | 14.0 percent maximum |
| Ash, dry basis | 0.5 percent maximum |
| pH, 10 percent slurry | 4.5 to 7.0 |
| Sulphur dioxide | 50 mg/kg maximum |
| Lead | 0.5 mg/kg maximum |
| Arsenic | 0.5 mg/kg maximum |
| Total plate count | 10000 cfu/g maximum |
| Yeast and mould | 500 cfu/g maximum |
| E. coli | Absent in 1 g |
| Salmonella | Absent in 25 g |
Common Markets Grades
Base starch is the first variable. Waxy maize gives the clearest and most stable pastes and is the usual choice where freeze thaw performance is the objective; tapioca gives a clean flavour and a short smooth body suited to dairy; potato gives high viscosity and clarity; regular maize gives an opaque, firmer paste at lower cost. Acetyl content is set within the permitted ceiling, with lightly acetylated grades used where only mild storage stability is needed and grades at the upper limit used for frozen products.
Two reagents are used, acetic anhydride and vinyl acetate, and they give products that can be told apart, with the choice generally driven by plant configuration and by the residual reagent specification rather than by function. Physical forms are cook up granular starch, which needs a heat step, and pregelatinised drum dried or extruded starch, which hydrates cold and is used in instant desserts and dry mixes. Agglomerated instant grades are made to improve dispersion. Grades are bought on a rapid visco analyser curve as much as on acetyl content.
Applications
- Frozen sauces, gravies and ready meals, where acetylation prevents the retrogradation and water release that follow freeze thaw cycling
- Chilled dairy desserts, yoghurt and fromage frais, holding a smooth body without weeping over shelf life
- Bakery fillings and fruit preparations, staying clear and glossy rather than clouding during storage
- Instant pudding and dessert mixes, in the pregelatinised form that thickens in cold milk or water
- Soups and sauces held chilled, where a native starch would firm up and turn short in the pack
- Noodles and pasta products, contributing softness and limiting the staling that comes with amylose retrogradation
- Meat and poultry brines, holding water through cooking and chilled storage
- Batters and coatings, where the lower gelatinisation temperature gives faster viscosity development during frying
- Paper coating and textile sizing outside food, using the improved film clarity and flexibility
China Manufacturers of Acetylated Starch
Top Acetylated Starch manufacturers in China.
- Dezhou Bailixin Biological Co., Ltd.3 ingredients in the directory
- Hangzhou Starpro Starch Co., Ltd.6 ingredients in the directory
NanTong GaoFeng Biotechnology Co., Ltd.10 ingredients in the directory
Suzhou Gaofeng Biotechnology Co., Ltd.11 ingredients in the directory
Company names and logos are the property of the manufacturers themselves. They are listed here because our own directory records them as producing this ingredient. A listing is not an endorsement by them, and we do not represent them or speak on their behalf.
Regulatory Status
In the United States 21 CFR 172.892 permits acetylated starch as a food starch modified, lists acetic anhydride and vinyl acetate among the permitted treatment agents, caps the acetyl content of the finished starch and limits residual reagent and by product. It is declared on United States labels as modified food starch or food starch modified rather than by its chemical name.
In the European Union it is authorised as E 1420, acetylated starch, under the food additives framework and is permitted quantum satis in most food categories, with purity criteria including an acetyl group limit and a residual vinyl acetate limit set out in the specifications regulation. As a chemically modified starch it must be declared as a food additive rather than simply as starch. JECFA has evaluated the modified starches as a group and maintains a specification monograph for starch acetate, and Codex lists it among the permitted additives in the General Standard for Food Additives.
Manufacturing Process
Native starch is slurried in water at around 35 to 40 percent solids and the pH is raised to about 8 to 9 with dilute sodium hydroxide, since the esterification proceeds on the alkoxide form of the starch hydroxyl. The reaction is run below the gelatinisation temperature, usually at 25 to 35 degrees Celsius, so the granule remains intact and the modified starch can be recovered by filtration afterwards. A neutral salt is often present to further suppress swelling.
Acetic anhydride or vinyl acetate is metered into the agitated slurry over a controlled period while sodium hydroxide is dosed continuously to hold the pH, because each acetyl group transferred releases an acid that would otherwise drop the pH and stall the reaction. When the target acetyl content is reached, usually within one to two hours, the slurry is neutralised to about pH 5.5 to 6.5 with dilute hydrochloric or sulphuric acid. The starch is then washed on a countercurrent hydrocyclone battery or a rotary vacuum filter train to remove the sodium acetate formed, any unreacted reagent and the acetaldehyde by product where vinyl acetate has been used. The washed cake is dewatered and flash dried in hot air, then cooled, milled, sieved, passed over a magnet and metal detector and packed. For a pregelatinised grade the washed slurry is cooked and dried on a heated drum and the film milled to powder.
