The biological introduction of peanuts
Peanut is one of China’s six major oil crops, production is also very large. China is rich in peanut resources. Every year, more than 3.5 million tons of peanuts are used to make oil. About 1.2 million tons of peanut meal is produced every year, which is rich in protein The amino acid composition is close to that of animal protein, which is an ideal source of edible plant protein.
The chemical composition of peanuts
●Peanut kernel contains protein 26-30%, fat 35-36%, sugar 13-19% and crude fiber 2.7-4.1%;
●Peanut protein is mainly globulin, its amino acid composition ratio is close to animal protein, absorption rate is up to 90%;
●The contents of peanut kernels including VA0.26IU per gram, VB18.5-14 µg, VB21.05-1.57 µg, niacin 88-200 µg, biotin 0.3 µg, inositol 1800 µg, and the trypsin inhibitor that can reduce the nutritional value of protein were only 1/20 of soybean;
●Roasted peanuts produce a pleasant and special aroma. The volatile aroma contains more than 230 kinds of components, among which aliphatic, aromatic and heterocyclic compounds are particularly abundant;
●The protein content of peanut cake after oil pressing is as high as 60%, which contains 8 kinds of amino acids that human body needs is complete protein.
●Peanut oil is a non-drying oil, containing a large number of fatty acids, especially unsaturated fatty acids, which can be processed into salad oil, luzhou-scented oil, pure peanut oil and other advanced edible oils.
Peanut Oil Industry in China
At present, high-temperature pressing and solvent extraction are basically adopted in peanut oil production in China. One of the problems is protein production and denaturation. Water-soluble protein content, V group elements and ammonia-soluble index (NSI) are all reduced in varying degrees, resulting in loss of nutritional value. Second,in the high-temperature pressing process, 10-18% peanut shells must be added so that the friction coefficient of the oil press chamber can meet the conditions of peanut kernel oil extraction. The peanut shell is composed of crude fiber. The addition of peanut shell not only absorbs oil, but also makes the rate of peanut cake separation impossible. Groundnut cake was used as cheap for fertilizer and feed. Not only the low processing efficiency of peanut oil, but also the added value of peanut cannot be applied and improved. From the perspective of macro benefits, the major protein resources of 1.3 billion Chinese people have not been properly utilized.
The advantage of cold pressing of peanut kernel to make oil
Compared with the current high-temperature pressing or extraction process, the technology of cold-pressed oil from peanut kernels has the advantages of simple process, energy saving, less investment in equipment and small occupation area.
First, the double screw cold press does not need to add peanut shell as an auxiliary material, so better peanut kernel cake can be obtained.
Secondly, the whole process realized the low temperature press, in the process, the high temperature value is less than 80°C, under this condition. high quality peanut oil can be obtained.
Thirdly, the protein content of 50 to 60% high quality crude protein powder can be obtained after the cold pressed peanut cake is crushed, which lays the foundation for the further transformation of protein into food protein.
Comparison of Peanut Oil production process
- Traditional technological process
10-18% peanut shells – peanut kernels – cleaning and removing – crushing – steaming – frying – wool oil – scouring – product – cake
- Cold pressing process
Groundnut kernels – cleaning and removing impurities – conditioning – cold pressing oil – crude filtration – cleaning – high quality cold pressed oil – high quality groundnut cake – grinding – peanut crude protein powder