Modified starch is produced from natural starch as a result of physical, enzymatic and chemical changes. Thanks to these processes, it is possible to use it in a variety of ways, not only in the food industry. Modified starch is a safe food additive that improves the features of products, but its presence is not always necessary, and is sometimes used by producers as a "filler".
Natural and modified starch
Starch is a carbohydrate composed of glucose molecules that form two fractions: linear amylose and branched amylopectin. Properties and the possibility of industrial use depend on the proportion of both fractions in starch from a given plant. Starch is a natural substance found in almost all plants and widely used in industrial production, not only in food. The most economically important starches, accounting for over 99% of world production, come from maize, wheat, cassava and potatoes. Potato starch is considered the cleanest and the best quality.
Natural starches extracted directly from the plant and untreated are used in industry, but they are not very resistant to physical conditions in modern food processing technology. Modified starches have been used in the food industry since the 1940s. Modifications of starch allow to give it new features and improve functional properties, which affects the quality of end products with the addition of starch. Modified starch in food gives it the right texture, thickens it, prevents them from clumping in loose products, and also allows you to prepare instant dishes, e.g. jelly, which you just need to pour boiling water over and stir.
ImportantModified starch and genetically modified food
It should be noted that modified starch has nothing to do with GMOs and genetic modifications, and changes in its properties are made through physical, enzymatic and chemical methods. Various types of modified starch are safe food additives that can be found in the composition of products under the symbols E1400 to E1500. The methods of their production are specified in the recommendations of the FAO / WHO Expert Committee for Food Additives and are used in industry on the basis of Polish and European standards.
Starrymodified are safe food additives, but when choosing a food product, you should pay attention to the full composition and rationally assess whether a given product will not harm your he alth in the long run. Often, modified starch-containing foods also contain large amounts of s alt, monosodium glutamate and unhe althy hydrogenated vegetable fats such as palm oil. There are also products in which starch is unnecessary, and the manufacturer adds it, for example, to increase the weight of the product or adjust the density to consumer preferences, which applies to some natural yoghurts or cold meats.
Starch modification methods
Starch is subject to three basic types of modification, which enable its more effective use in industrial production and provide better properties of the finished product.
Physical modifications- natural starch is subjected to heating at high temperature, initial pasting and then drying on drying rolls. The starch crystal structure disappears during the process. Thanks to this treatment, starch gains the ability to dissolve in cold water or milk, and it dissolves faster in hot water. In the light of food law, physically modified starch is not a food additive, but a foodstuff like natural starch.
Enzymatic modifications- as a result, starch is hydrolyzed, i.e. decomposed into compounds with a lower molecular weight. This is the main direction of starch processing, resulting in m altodextrins and syrups. Starch breaks down into other chemical compounds, so enzymatic methods are not strictly modified.
Chemical modifications- during chemical modifications, hydroxyl (-OH) groups present in the starch rings are replaced with other chemical substituents. Starch is modified in the processes of oxidation, esterification and etherification. The structure of starch macromolecules is changing, which has a great impact on its physicochemical properties.
Properties of modified starch
Modified starches obtained as a result of transformations differ significantly in properties from natural starch. The rheological properties obtained in starch modification processes, which are widely used in industry, are:
- binding of very large amounts of water with substances dissolved in it,
- wide viscosity range,
- variable gelatinization temperature from room temperature to over 100 ° C,
- creating different types of gels,
- not succumbing to the retrograde process (precipitationstarch molecules from the resulting structure),
- clarity and transparency of pastes and gels,
- absorbing various compounds, e.g. flavors, fragrances, alcohols,
- ability to stabilize emulsions and suspensions,
- ability to form elastic membranes.
Use of modified starch in the food industry
Depending on the modifications, starches have specific features and are used differently in food processing. Also, the different botanical origin of the starch and the intensity of the applied process result in the production of a very wide range of starch derivatives with different properties. They are divided into general categories that determine the best possible uses for each type of modified starch.
Oxidized starches- the gels they create have low viscosity, high hardness and are stable over time. They are used in the production of puddings, pudding creams, whipped cream and powdered cake mixes. They are a component of confectionery shells and fillings, e.g. in soft candies. They can also be used for coating, sprinkling and breading products, because they adhere well to the product's coating, and after roasting and cooling they are crispy.
Acid starches- their use in the technological process allows the introduction of large amounts of starch into the product without the difficulties of mixing and pumping. After cooling, they form a compact and flexible gel. As a result, acid starches are used as an ingredient of confectionery bodies and fillings, and as a partial replacement for wheat flour in confectionery cakes.
Mono-starch esters- the most widely used in the food industry are acetylated starches, which do not undergo retrogradation, show high stability and clarity of pastes and a lower pasting temperature. They are used in the production of traditional and instant noodles.
Mon starch phosphatesare good emulsion stabilizers, e.g. in vinegar-oil systems, as well as freeze-thaw-resistant thickeners. They are used to thicken soups, sauces and dressings.
Cross-linked starches- they are most often used in food processing. Cross-linked starches are resistant to temperature changes, mechanical treatment and the pH of the manufactured and finished product. They are mainly used as a thickener in many products, e.g. sausages and cold cuts.
Agglomerated and instant starches- are physically modified starches that dissolve perfectly even in cold water and milk. They are usually used for cold preparationsmilk desserts, jelly, sauces, milk drinks and cottage cheese. They enable instant dissolution of kissel or soup after pouring boiling water. Modifying starch by forming complexes with fat allows it to be used as a fat substitute in ice cream.
Other uses of modified starch
The properties of modified starch are also used by other industries, not only food. Thanks to the enormous possibilities of changing the characteristics of starch, the list of applications is over 1000 and is still expanding. The most popular directions for the use of modified starch include: production of high-quality paper, corrugated cardboard, biodegradable plastics, adhesives, production of superabsorbents used in agriculture to improve soil quality, production of disposable dressings and diapers, microcapsules used in medicine and cosmetics, production of explosives.
Sources:
1. Walkowski A., Lewandwowicz G., Modified starches. Technological properties and scope of application, Przemysł Spożywczy, 2004, 5, 49-51 2. Walkowski A., Olesienkiewicz A., Selection criteria for modified starches in food processing, Przemysł Spożywczy, 2005, 8, 54-573. Leszczyński W., Application of modified starches in the food industry, Przegląd Piekarski i Cukierniczy, 2006, 5, 54-56 4. Krępulec A., Possibilities of using grain starches in industries other than food, Przegląd Zbożowo-Młynarski, 2008, 9, 61-62