Hydrophilic colloid refers to a solution or colloid that can be dissolved in water and hydrated under certain conditions to form a viscous, slippery solution or colloid. According to different raw materials, it can be divided into animal glue , plant glue, Seaweed glue, microbial glue, chemically modified glue, etc. Hydrocolloids/edible gums are widely used in various common foods in life such as soft candies, meat products, jams, jellies, etc. Different hydrocolloids have different gel properties. The following are the xanthans brought by edible gum nets Comparison of the properties of several hydrophilic colloid gels such as gum, gellan gum, agar, carrageenan, sodium alginate, and gelatin.
Hydrocolloids are widely used as food additives, mainly as thickeners, stabilizers, etc. Among them, agar can be used as a gelling agent in soft candies to increase the taste and transparency of the soft candies; xanthan gum can be added to meat products as a stabilizer to increase the water holding capacity of the product; pectin and gellan gum also Can be used as a gelling agent for jams and jellies.
1. Xanthan gum
In terms of gel properties, xanthan gum solution has good heat resistance, salt resistance and acid and alkali resistance stability; the viscosity of xanthan gum solution is proportional to the concentration and rises with the concentration; the viscosity of the gum solution containing NaCl is PH2 It is slightly affected by pH between .5 and 12.
2. Gellan gum
Gellan gum is a newly developed microbial hydrocolloid in recent years. It has incomparable advantages over other hydrophilic colloids. Its gel characteristics mainly include the following points:
(1) High-quality gel can be formed at low concentrations (0.05%-0.25%);
(2) It is very stable under heating and low pH conditions, and can form gels between PH3.5-7.0;
(3) Gels formed by sodium or potassium ions can be restored after addition, but gels formed by magnesium or calcium salts cannot be restored;
(4) It can be used in combination with other hydrophilic colloids such as xanthan gum, modified starch, locust bean gum, etc. to achieve better results;
Agar, carrageenan, and sodium alginate all belong to seaweed gum. The characteristics of its gel system are: agar is a thermally unstable gel with poor thermal stability and acid stability. The texture is smooth but opaque. In general systems The dosage is higher.
Carrageenan is stable under both neutral and alkaline conditions, but under acidic conditions (PH ≤ 3.5), the carrageenan molecules will degrade, and heating will also accelerate the degradation rate.
Carrageenan can form a gel at a concentration of more than 0.5% in the water system, and can be as low as 0.1%-0.2% in the milk system.
Carrageenan can interact with proteins, and the result depends on the isoelectric point of the protein and the pH value of the solution. For example, in neutral drinks, carrageenan can form a weak gel with milk protein to maintain the suspension of particles and avoid rapid deposition of particles; The interaction with proteins can also be used to remove unwanted proteins from the system; some carrageenans also have the function of rapidly forming proteoglycan flocculent deposits, but the deposits are easily redispersed in flow.
5. Sodium alginate
The main characteristics of the sodium alginate gel system are: the gel formed is thermally irreversible; the transparency is slightly poor; it can form a gel with calcium salt; it cannot gel in systems with high solid content.
Gelatin is a hydrophilic colloid derived from animals. Its gel system characteristics are: gelatin is a very elastic colloid; gelatin has a low dissolution and solidification temperature, and it is a thermally unstable gel. , poor acid stability and will harden in a refrigerated environment.