Commonly used food preservatives are benzoic acid, sorbic acid, parabens, calcium (sodium) propionate, calcium (sodium) lactate, sodium diacetate, dehydroacetic acid, etc.
Preservatives that have antiseptic effect but are not currently used as food additives and are easily abused include salicylic acid, p-hydroxybenzoic acid, m-hydroxybenzoic acid, etc.
Determination of fresh-keeping and antioxidants include butylated hydroxyanisole (BHA), 2,6-di-tert-butyl-p-cresol (BHT) and tert-butyl hydroquinone (TBHQ), p-tert-butylphenol, 2-benzene phenol, 2-naphthol, 4-phenylphenol, etc.
Food preservatives play a role in preservatives mainly in three ways:
1. Inhibit the formation of microbial cell walls;
2. Affect the function of cell membrane;
3. Inhibit protein synthesis or denature protein.
Each preservative mainly acts on microorganisms in one way. Therefore, if a single preservative is used, the "antibacterial spectrum" will be relatively small, and a relatively large concentration is often required, which is easy to exceed the standard.
Many foods, especially nutrient-rich foods, often use multiple preservatives in combination to expand the "antibacterial spectrum", reduce the concentration of a single preservative, improve the preservative effect, and prolong the preservation time of food. For example, benzoic acid and tripyric acid preservatives are often used in combination to improve the preservative effect.
we divide preservatives into two categories: water-soluble and fat-soluble. Water-soluble preservatives mainly include benzoic acid, hydroxybenzoic acid (illegal preservatives), sorbic acid, small molecule organic acids, etc. (lactic acid, propionic acid, diacetic acid), as long as these preservatives are used for water-soluble or Water-soluble foods, such as drinks, cakes, seasonings, etc.
Fat-soluble preservatives (preservatives) mainly include hydroxybenzoates, butylated hydroxyanisole (BHA), 2,6-di-tert-butyl-p-cresol (BHT) and tert-butyl hydroquinone (TBHQ), p-tert-butylphenol, 2-phenylphenol, 2-naphthol, 4-phenylphenol, etc. These additives are mainly used in foods containing more oil or dried fruits.
Preservatives (preservatives) can only exert their preservative and fresh-keeping effect when they are fully dissolved or evenly distributed in the food medium. Therefore, according to the condition of the food matrix, it is possible to roughly determine which type of preservatives (preservatives) may be contained, and select the appropriate extract. Purification method to measure.
