Basic introduction to food thickeners(2)

2 Classification

So far the world has more than 40 kinds of food thickeners for the food industry, according to its source, can be broadly divided into four categories: thickeners made from plant exudates, thickeners made from exudates of different plant epidermal damage is the function of synthetic products can not reach; thickeners made from plant seeds, seaweed, thickeners made from land, marine plants and their seeds, in many cases, where the The water-soluble polysaccharides are similar to the exudate of plants after stimulation; thickeners made from animal raw materials containing proteins, which are extracted from animal skins, bones, tendons, milk and other raw materials, the main component of which is protein; semi-synthetic thickeners based on natural substances, which can be further divided into two categories according to their processing: cellulose and starch as raw materials, under the action of chemical raw materials such as acids, bases and salts This type of thickener can be divided into two categories according to its processing process: cellulose, starch as raw material, under the action of acid, alkali, salt and other chemical raw materials, after hydrolysis, condensation, purification process. The representative varieties are sodium carboxymethyl cellulose, modified starch, propylene glycol alginate, etc.; fungi or bacteria (especially the enzymes produced by them) and starch substances produced when the role of another type of widely used food thickeners, such as xanthan gum.

3 Functions

Food thickeners play an important role in maintaining the colour, flavour, taste, structure and stability of fluid foods and jellied foods.

The main purpose of thickeners in food is to give the food the required rheological properties, change the texture and appearance of the food, form the liquid, pulpy food into a specific form and make it stable and homogeneous, and improve the quality of the food in order to make the food have a sticky and smooth taste. For example, the quality of ice cream and snacks depends to a large extent on the state of formation of ice crystals, adding thickeners can prevent the formation of too large ice crystals, so as not to feel rough and crumbly tissue.

Thickeners have water solubility and stabilising properties, which allow the ice crystals generated during the freezing process to be fine-tuned and contain a large number of tiny air bubbles, resulting in a fine and uniform structure, smooth texture and neat appearance. When thickeners are used in jams, granulated foods, various canned foods, soft drinks and margarines, they give the products a satisfactory consistency. When organic acids are added to milk or fermented milk, they cause coagulation and precipitation of milk proteins, which is a serious problem in yoghurt drinks, but when thickeners are added, they make the products uniform and stable.

The gel effect of the thickener is to use its gelling properties. When the system is dissolved with a specific molecular structure of the thickener, the concentration reaches a certain value, and the composition of the system also reaches certain requirements, the system can form a gel. The gel is a spatial three-dimensional network structure, the mutual cross-linking and chelation between these macromolecular chains and the strong affinity between the thickener molecules and the solvent, are conducive to the formation of this spatial network structure,; conducive to the formation of gel. Some of the thickeners.