Chemical Properties of PGA

Chemical Properties of PGA

PGA (propylene glycol alginate) is processed from alginate by esterification. Compared with alginate, it has more advantages and unique application in the food industry. propylene glycol alginate can be soluble in water to form a viscous colloid and soluble in organic acid solutions. In the acid solutions with pH3-4, it can form gel but won’t generate sedimentation. It also has strong salt resistance and even in concentrated electrolyte solution, salt-out phenomenon won’t occur. It is stable under metal ions like calcium and sodium, that is, PGA helps to improve the stability of acids in food and to prevent the sedimentation in food and beverages caused by calcium and other high-valent metal ions.

Under weak base conditions, propylene glycol alginate PGA can generate a cross-linking reaction with protein and other polymer molecules like starch. When the pH value rises to 8-9 and the temperature remains relatively low, changes of rheological properties can be observed such as the increase of viscosity. At temperature 40-50℃, PGA can react with gelatin to form a kind of rapid solidification gel, which is thermal irreversible at the boiling point.

Apart from colloidal properties, propylene glycol alginate PGA has high lipophilicity and good emulsion stability because its molecules contain propylene glycol. Consequently, propylene glycol alginate PGA can be effectively used in such food and beverages of low pH value as lactic acid drinks and juice beverage. The lipophilicity of PGA solution can be effectively used as a stabilizing agent of cream, syrup, beer, beverages and salad oil. When lipophilicity of PGA is used, products of high esterification degree should be chosen because the higher the esterification degree is, the stronger the lipophilicity and the surface activity of PGA are. In addition, low-viscosity products should be chosen as possible.

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