1) Starch exists in the endosperm in the form of starch granules of different sizes.
(2) The size and shape of starch granules have an important influence on the function and properties of starch.
(3) The characteristics of amylose and amylopectin during heat treatment are very different:
The anti-retrograde properties of amylopectin are better than amylose.
(4) The straight/branch ratio of corn and the storage conditions after puffing have an influence on the starch digestibility and the formation of resistant starch
Experiments have shown that the longer the storage time, the higher the resistant starch; the lower the storage temperature and the higher the humidity, the more resistant starch.
The digestible starch content of puffed corn was significantly negatively correlated with resistant starch; the resistant starch content was positively correlated with fat and crude protein but not significantly.

Nutritional Value Characteristics of Feed Maize
(1) Corn is the most important energy feed in livestock and poultry feed, accounting for 60%-70% of the formula.
(2) High content of unsaturated fatty acids: the fat content of corn seeds is 3.5%-4.5%, which is twice that of barley and wheat; corn linoleic acid is as high as 2%.
(3) Low protein content and poor quality: generally corn crude protein is 7.2%-8.9%, lower than barley and wheat. The main protein types are gliadin, followed by gluten, and the digestibility is poor; the amino acid composition is unbalanced.
(4) The content of vitamins and minerals is low.

Factors Affecting Nutritional Value of Feed Maize
1) Corn is the most important energy feed material in monogastric animal diets.
(2) The traditional indicators for evaluating corn quality include test weight, dry matter, dry grain weight, total energy, total starch, and crude protein content as a supplement to the quality of feed corn.
(3) In the past, it was believed that corn is a grain with relatively stable feeding value, but this view has been proved to be incorrect in pig and poultry experiments, and starch, oil, and protein have certain changes.
(4) Differences in varieties and growth conditions result in the variation of corn nutrition indicators. According to Adisseo’s research, Hubei corn has the lowest total energy, and the crude fat content is significantly lower than that of corn in other regions.
(5) Starch content and digestibility are different
There are differences in amylose content, starch digestibility and starch granule diameter in different varieties of corn.
The total energy value and starch content varied little, but the branch/straightness ratio varied greatly among different cultivars.