Skim milk powder is one of the high protein products (High Protein Products), therefore, in addition to structural parameters such as grain size, solubility and temperature given during the process, as well as microbial parameters, the protein content of this product is of particular importance. Which can somehow play the most important role in the biological value and final price of the product. The minimum amount of protein in lean dry matter of this product is 31% in the National Standard of Iran No. (2012). In this short paper, using experimental data as well as mathematical equations, it is tried to explain that the minimum protein in the dry matter of skim milk powder according to Iranian milk produced in industrial and semi-industrial farms should be Be at least 33%. Therefore, consumers of milk powder should not accept numbers lower than this number from suppliers.
According to the studies of inputs to Shammeh Agriculture and Industry and Animal Husbandry Company, the average weight of non-fat dry matter of inputs to this factory during the last year is 8.49 ۵ 0.52 and the average protein is 0.07-0.21. It is 3%. Also, in another study on 231 thousand shipments of milk entering one of the factories in the country, the average fat-free dry matter was 0.27.28 ۴ 0.48 and the average protein was 0.055 ۱۹ 0.05.
According to the above data, which is an approximate representation of the amount of lean dry matter and milk protein in Iran, and considering an average of 3 to 5% of lean dry matter in cream, which will be deducted from lean dry matter of milk (high in opnions have been asked). Even if the average lean dry matter is considered to be 2.8% and the protein content is 3%, the total protein content (not in lean dry matter) of dry milk will be at least 33%. Considering the humidity between 3 to 5% in the milk powder produced with the lowest conditions, the amount of protein in the dry matter of skim milk powder should be at least 34%.
In cases where the amount of protein and dry matter in milk is higher than the standard set in Iran, for example, if the amount of dry fat in a milk is 8.7 and its protein is 3.2%, and even the amount of dry fat input To cream, it should be 3 to 5%. The amount of protein in the dry matter in skim milk powder, if the humidity is between 3 to 5%, with a minimum of at least 35%.
Now consider a weak milk with a protein and fat-free dry matter content of 2.8 and 8%, respectively. In the least cases, the protein in the dry matter of skim milk powder is 33.5.
The question may be asked why, despite the large changes in the amount of lean dry matter and raw milk protein, the rate of change in dry milk protein is not high? The reason can be attributed to the conversion factor so that when the amount of lean dry matter followed by raw milk protein is high, the conversion factor of raw milk to powdered milk decreases, in other words, less than a small amount of raw milk per kilogram of powdered milk. It is produced as a result of which the amount of milk powder protein is somewhat higher. And when the raw milk input is weak, it means that the dry matter is fat-free and its protein is very low. More raw milk is needed to produce one kilogram of powdered milk, so in practice raw milk protein will be multiplied by a larger factor. And in this way, the protein in the dry matter of skim milk powder (if the milk powder is between 3 to 5% in terms of moisture content) is always a number between 33 to 36%.
It should be noted that in this study, in all cases, minimal cases in favor of reducing the amount of protein in milk powder have been considered. The minimum amount of protein in lean dry matter produced in dry milk is calculated.