The annual maize (corn) output of China ranks only behind that of the United States (U.S.), but its maize processing industry, although it is growing rapidly, still lags behind some developing countries in terms of scale, variety and level of processing technology.
At present, the effective utilization and comprehensive processing of maize is of the utmost importance to China. The goal is to create conditions to make processed corn products more functional and meet customer demands both in terms of quality and quantity.
In recent years, China’s maize processing ability improved substantially with an annual growth rate of 20%, particularly in the main maize producing provinces of Jilin, Heilongjiang, Liaoning and Shandong. A government estimate put the country’s maize processing ability at 24.5 million tonnes in 2007, a share of about 20% of maize output.
While progress is being made in the development and growth of the maize processing industry in China, it still has numerous challenges and obstacles to overcome.
Compared with the U.S. and other developed countries, China’s maize conversion is at a lower level. Maize used for feed accounts for more than 65% of all maize production, and 40% of that total is used for feed directly rather than through processing. Therefore, every year a large amount of maize used for feeding livestock and poultry directly leads to enormous waste and reduces the rate of conversion of maize. In addition, the utilization of maize is poor. Because of the technology and equipment constraints, straw and corncobs with high value haven’t been used effectively.
With the maize processing industry growing, the demand for raw materials is also increasing. Planting a single species has become a limiting factor for the Chinese maize processing industry. As the Chinese traditional modes of production only pay attention to the production of maize, some of the special varieties (such as waxy maize for industrial use) have not experienced a good promotion and development.
The Chinese maize quality standard system is not well defined. Compared with other developed countries, there are only a small number of standards that lack detailed provisions, so they have poor practicability.
In addition, the safety and hygiene standards regarding Chinese maize and maize products are minimal. As a result of different maize processing methods for food and feed, their safety and hygiene requirements are not the same. There is still a big gap in this area between China and developed counties.
There are a large number of maize processing enterprises in China, but most are small-scale operations. Due to the lack of human resources in small factories, the low level of management, low levels of production and high costs in the competitive market, it is difficult to form a maize industry chain.
Another obstacle is that the feed industry, livestock industry and maize production areas are geographically incompatible to the pace of development. The maize production regions are mainly located in the north. This causes a waste of maize resources in the north and shortages in the south. At the same time, China’s feed industry has developed rapidly, but the pace of feed production is inconsistent with livestock production.
ANIMAL FEED APPLICATIONS
Since 1982, the livestock industry in China has developed the fastest in the world, and the livestock industry is, of course, a main driver of the feed industry There are three kinds of maize-based feed in China: silage feed, formula feed and special feed.
Maize straw is the main raw material of silage feed. Because of their nutritional value, waxy corn and sweet corn stems are also applied in feed production. After maize is milled, some ingredients are added to make multiple formula feed, such as high-oil feed, high-starch, highlysine and high-fiber feed.
The addition of the special nutritional components improves the milking rate of cows and laying rate of hens, improves the feed utilization rate and increases the antiviral ability of animals, thus improving economic efficiency. The Chinese feed industry also makes use of byproducts to produce multi-functional feed rich in vitamins and protein.
The time when maize was used as staple food in China has passed. At present, the industrial products using maize as raw material are as follows: starch sugar, maize oil, alcohol, monosodium glutamate and xylitol.
Maize provides abundant carbohydrates for China’s fermentation industry. The glucose obtained by enzymatic hydrolysis is an excellent material in the fermentation industry. For example, both corn steep liquor and powder syrup can be used to produce many products, including alcohol and beer. Starch sugar deep processing has developed quickly across the globe in recent years. Starch sugar, one kind of important starch deep-processing products, is prepared by enzymatic hydrolysis of starch. It is also an important raw material for the Chinese food industry, which can be a beneficial supplement to daily consumed sugar.
There are three kinds of products that utilize starch sugar: high fructose syrup, which has taken the place of sugars in many carbonated beverages in the U.S.; Sorbitol, which is applied widely in food, candy, toothpaste, cosmetic and pharmaceutical fields; and oligosaccharide, a healthcare sugar used in health food, infant food and sports beverages.
Maize oil, which is extracted from maize germ, is mainly composed of unsaturated fatty acid. Linoleic acid is an essential unsaturated fatty acid and plays a role in the prevention and treatment of atherosclerosis and cardiovascular disease. Moreover, the sitosterol in maize oil has many kinds of functions, such as cholesterol reduction, antioxidation, xerophthalmia, nyctalopia, dermatitis and bronchitis expansion prevention, etc. As a result of the above advantages, maize oil is very popular in China.
Monosodium glutamate, which is also popular in China, is produced from maize starch.
Xylitol is a new kind of sugar crop extracted from corn cobs. It is a good functional food for dental cavities, diabetes and mellitus hepatitis patients. It can be easily absorbed by the human body without the existence of insulin. Xylitol is also widely applied in beverages, candy and toothpaste.
MEDICINE AND ENERGY
There are many applications for processed maize in China in the medical, biological and energy fields.
In medicine, maize starch products can be made into tablet molding reagent and medicine-release products. The latter are largely used for the infusion of glucose injection, oral glucose and other nutritional supplements. Mannitol for lowering the intraocular pressure and cerebral pressure, aldehyde oxidation starch for the treatment of Uremia, glutamine for the treatment of gastrointestinal ulcer disease, penicillin and other antibiotics are all the starch-based products.
Another trend that’s gaining momentum is maize starch-based products taking the place of petrochemicals. The ethylene glycol (raw material of antifreeze, polyester fibers and polyester plastics) produced by starch has been widely used in PLA plastics, PLA fiber and PTT fiber.
The most potential and promising field of maize amylose is producing degradable plastics, replacing the use of polystyrene. This will be widely used in packaging of agricultural products and the industrial film industry. In many areas of China, mulching has become one of the key measures for increasing food and vegetable production. However, the use of plastic film has caused serious environmental pollution. The development of biodegradable plastics on the protection of the environment is of great significance.
In China’s "the tenth five-year plan outline," it mentioned that developing maize-based fuel ethanol is an effective way to save petroleum resources. The production and use of ethanol gasoline will not only ease the economic pressure caused by petroleum resources shortage, but also open up a new path to solve the aging problem of food.
The maize processing industry is a waste-free, non-polluting, high valueadded and effective industry. As the world’s second largest maize producing country, China’s maize processing industry has a broad prospect for the future.
Liu Zhongdong and Sun Youning are professors at the Henan University of Technology.