Factors affecting the effect of food thickeners

Release time:

2023-03-13 10:50

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Effect of structure and relative molecular weight on viscosity: Generally, thickeners are colloids that are easy to form a network structure or have more hydrophilic groups in solution, and have higher viscosity. Therefore, the viscosity of thickeners with different molecular structures may vary greatly even under the same concentration and other conditions. With the increase of the average relative molecular weight of the same type of thickener, the probability of forming a network structure also increases, so the viscosity of the thickener is closely related to the relative molecular weight, that is, the greater the relative molecular weight, the greater the viscosity. The viscosity of food decreases during production and storage, which is mainly due to the degradation of thickener and the decrease of relative molecular weight.
Effect of concentration on viscosity: with the increase of the concentration of the thickener, the molecular elastic volume of the thickener increases, the probability of interaction increases, and the adsorbed water molecules increase, so the viscosity increases.
Effect of pH value on viscosity: The pH value of the medium is closely related to the viscosity and stability of the thickener. The viscosity of thickener usually changes with the pH value, for example, the viscosity of sodium alginate is stable when the pH is 5~10; When the pH value is less than 4.5, the viscosity is significantly increased (but under this condition, the viscosity is unstable due to acid catalytic degradation, so it is better to use it under near-neutral conditions). When the pH value is 2~3, the alginate glycerol ester presents the maximum viscosity, while the alginate sodium precipitates. Gelatin has the lowest viscosity at the isoelectric point, while xanthan gum (especially in the presence of a small amount of salt) has little effect on viscosity. The hydrolysis of glycosidic bonds of polysaccharides is carried out under the condition of acid catalysis. Therefore, in foods with strong acid medium, sodium alginate with straight chain and sodium carboxymethylcellulose with small side chain are easy to degrade and cause viscosity reduction. Therefore, in foods such as soda and yoghurt with high acidity, it is advisable to choose alginate glycerol ester and xanthan gum with larger or more side chains, which have a higher steric resistance and are not easy to hydrolyze. However, sodium alginate and CMC should be used in near-neutral foods such as soymilk.
Effect of temperature on viscosity: with the increase of temperature, the speed of molecular motion increases, and the viscosity of general solution decreases. For example, the viscosity of sodium alginate solution under normal use conditions decreases by 12% for every 5-6 ℃ increase in temperature. With the increase of temperature, the chemical reaction speed is accelerated, especially under the condition of strong acid, the hydrolysis speed of most colloids is greatly accelerated. When the polymer colloid is depolymerized, the decrease of viscosity is irreversible: in order to avoid the irreversible decrease of viscosity, try to avoid the colloid solution being heated at high temperature for a long time. In the presence of a small amount of sodium chloride, the viscosity of xanthan gum changes very little in the range of - 4~+93 ℃, which is a special case of thickeners. Xanthan gum and propylene glycol alginate with large steric hindrance have good thermal stability.
The effect of shear force on the viscosity of thickener solution: the viscosity of thickener solution with certain concentration will change with the processing and transmission methods such as stirring and pump pressure.
Synergistic effect of thickeners: if the thickeners are mixed and compounded for use, there will be a viscosity superposition effect between the thickeners. This superposition can be synergistic. After a certain time, the viscosity of the mixed solution is greater than the sum of the viscosity of each component, or a higher strength gel is formed. This superposition can also reduce the effect. For example, gum arabic can reduce the viscosity of tragacanth gum. Sometimes, using only one thickener can not achieve the desired results, so it must be used in combination with other emulsifiers to play a synergistic effect. The thickener has a good synergistic effect with CMC and gelatin, carrageenan, guar gum and CMC, agar and locust bean gum, xanthan gum and locust bean gum, etc.
Influence of other factors on viscosity: In addition to pH value and temperature, there are many factors that affect viscosity. Add non-aqueous solvent or increase the amount of solvent (such as alcohol) that can be miscible with water in the sodium alginate solution, the viscosity of the solution will increase, and eventually lead to the precipitation of sodium alginate. However, the high concentration of surfactant will reduce the viscosity of sodium alginate, and finally make the alginate salt out of the solution, and the monovalent salt will also reduce the viscosity of dilute sodium alginate. Due to the different degree of polymerization, the relative molecular weight also varies greatly, so the thickener has no accurate fixed relative molecular weight, which is generally expressed by the average relative molecular weight or relative molecular weight range.

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Performance comparison of various cold drink stabilizers

1. High-viscosity carboxymethyl starch (CMS) is a new type of thickening and emulsifier used in frozen drinks. It is characterized by instant dissolution and can form a uniform, transparent and stable solution within 5-10 minutes. No odor. 2. Agar: heat-resistant and acid-resistant. Its addition of ingredients can improve the tissue state of cold drinks, improve the coagulation ability, increase transparency and expansion rate, and enhance the melting resistance. 3. Edible gelatin: It has strong foaming property, and can form a gel during freezing and hardening, so it can keep the ice cream soft, loose and delicate. 4. CMC: thicken and coagulate, stabilize the emulsion and suspension, suspend the particles, and inhibit the change of ice crystals or sugar crystals. If a large amount of starch exists, it can prevent dehydration and shrinkage, stabilize the foam, reduce the shrinkage of oils and lipids, and improve the taste. 5. Sodium alginate: It can improve the mixing speed of ingredients and leave a fragrance in the mouth. In addition, it reacts with the calcium ions in milk to generate calcium alginate, and then form a uniform jelly, which can well maintain the shape of ice cream and prevent volume shrinkage and tissue sanding. 6. Xanthan gum: it still has high viscosity and shear resistance at low concentration. When designing soft soft soft cold drinks, it should be added more. When it is necessary to increase the melting resistance of cup ice cream, it should be added appropriately. When designing pure natural ice cream, it should be used skillfully to increase the soft, fresh and delicate feeling. 7. Guar gum: it has strong thickening ability and shear resistance. At the same concentration, its viscosity is much higher than other colloids and only inferior to xanthan gum. It is the main raw material for all kinds of popsicles and ice cream. It is the main emulsification stabilizer for the production of soft cotton lollipop and ice cream. Its soft cotton is different from sodium alginate (brittle) and xanthan gum (soft), but it is smooth, tender, delicate and tastes good. 8. Carrageenan: its main feature is melting resistance. 9. Pectin: acid resistance, color, fragrance and taste are all good. It is also a good raw material for fruit and vegetable ice cream with soft, delicate taste.

Stabilizer -- an indispensable tool in the beverage industry

In the process of storage, the beverage is prone to sedimentation and suspension, which not only affects the sense, but also affects the flavor and quality of the beverage. The stabilizer solves this problem and becomes an indispensable and important additive in the beverage industry.

Factors affecting the effect of food thickeners

Effect of structure and relative molecular weight on viscosity: Generally, thickeners are colloids that are easy to form a network structure or have more hydrophilic groups in solution, and have higher viscosity. Therefore, the viscosity of thickeners with different molecular structures may vary greatly even under the same concentration and other conditions. With the increase of the average relative molecular weight of the same type of thickener, the probability of forming a network structure also increases, so the viscosity of the thickener is closely related to the relative molecular weight, that is, the greater the relative molecular weight, the greater the viscosity. The viscosity of food decreases during production and storage, which is mainly due to the degradation of thickener and the decrease of relative molecular weight.

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