During the extrusion process, the temperature of the food processing environment is high, and at the same time, a large pressure is applied to the related raw materials. These two parameters will damage or reorganize the nutrients therein. Of course, for all kinds of inorganic substances such as sodium chloride, changes in the environment will not affect their chemical and physical properties, so all kinds of inorganic substances are not within the scope of this study, and the object of this study is all kinds of organic substances nutrient content.
1. The influence of extrusion process on carbohydrate composition
(1) The influence of starch composition
In the process of food extrusion and puffing, the added starch contains amylose and amylopectin. In the actual processing process, it will be affected by the environment. After the raw material is expanded, the hydrogen bonds in the starch chain will be broken, and at the same time, the starch granules will be disintegrated, the starch will be fully gelatinized, and a part of the starch in the extrusion and expansion will be Direct "cutting", that is, the molecular chain of starch is cut, making starch gelatinized. After the starch molecular chain is shortened, it is more conducive to the absorption, dissolution and digestion of nutrients by the human body. At the same time, after the gelatinized starch molecules are extruded, the starch molecules will also form a network structure in a weakly related state, which can be extended. Shelf life of food. In addition, if the starch is cross-linked by phosphoric acid esterification, the freeze-thaw stability can be improved to a certain extent, and the water absorption rate and heat loss of the starch can also be reduced.
(2) The influence of sugar
Food usually contains a variety of sugar materials. As a commonly used sweetener, it will be mixed in food raw materials and will appear in a molten state during extrusion and puffing. If the extrusion puffing temperature is higher than 250℃, it will cause caramelization, in addition to darkening the color of the product, it will also produce a bitter taste, and in severe cases, the machine will be blocked. During the extrusion process, if the sugar and oxyacid react, a Maillard reaction will occur, resulting in unnecessary consumption of amino acids, especially lysine. A mild reaction can stimulate appetite, but there is a potential mutagenic effect. .
2. Influence of extrusion process on amino acid and protein composition
(1) Influence of amino acid composition
In the production process of extrusion and puffing of food, Maillard reaction occurs with saccharides for lysine in the process of extrusion and puffing, which increases the content of amino acid in the food. For example, after corn is extruded, the content of protein and fat will be significantly reduced, and the content of water-soluble components and amino acids will be significantly increased. At this time, it can be speculated that during the extrusion and puffing stage, the protein molecules undergo hydrolysis, and the protein is large. The molecules are converted into small amino acid molecules, which are easier for the body to absorb.
(2) The influence of protein composition
The analysis of protein is a research hotspot in the extrusion process of food. After extrusion and puffing, amino acids are more easily absorbed by the body due to protein hydrolysis. There are two explanations for the hydrolysis principle of egg self-quality: one is that the spatial structure of the protein is destroyed and transformed into a peptide chain structure. At this time, it is easy to hydrolyze and become amino acids in the human body. Compared with proteins, peptide chains are easier to It is digested and absorbed by the human body; the second is that it can convert protein into amino acids, that is, protein has been hydrolyzed.
For the extrusion method, it is found that various vegetable proteins are more easily hydrolyzed, and the current food industry has begun to analyze how to improve the quality of food by adding myogenin to the produced food. However, this process requires the selection of a scientific extrusion and puffing process. Through the efficient use of this type of technology, various types of food can increase the nutritional content of the food without losing the original flavor. In addition, the related extrusion puffing process system can also be appropriately upgraded.
In summary, extrusion technology has been moderately used in the current food production and processing process, which means that it is likely to have a certain impact on various nutrients. For the development of carbohydrates, it is mainly to shorten the length of the starch chain, making it easier for the human body to digest and absorb: for the processing of refined ingredients, if the temperature is too high, the sugar will be denatured, affecting the taste and the total amount of nutrients; for protein and amino acids The effect is mainly reflected in the amino acid content, increasing protein conversion and hydrolysis, which is beneficial to human absorption.
