In recent years, consuming "black food" has become a fashion in the international market. The so-called black food mainly refers to foods whose natural pigments are black or purplish red, such as black rice, black beans, black sesame seeds, black fungus, mushrooms and Nostoc flagelliforme. The nutrition is particularly rich and comprehensive, the structure is reasonable, and the natural color, smell, taste and health care functions are integrated. The experiment shows that with the increase of natural pigments from shallow to deep, the more nutrients and contents, the more reasonable the food structure. Take beans as an example. White beans contain about 22% protein, 36% soybeans, 37% mung beans and 49% black beans. Another example is black rice, which contains carotene and vitamin C that white rice lacks. Its protein and plant fat are 0.5 ~ 1 times higher than that of white rice, and B vitamins and minerals are 0 ~ 3 times higher than that of white rice.

Black food with health care function is a fashionable food in the world today. Integrating color, smell, taste and health care, it has broad development prospects and huge economic and social benefits in bioengineering, agricultural product processing and comprehensive utilization of food industry, which has attracted great attention at home and abroad.

Green, blue and white agriculture

Agricultural production based on soil and water is called "green agriculture". Green revolution is a slogan put forward by developed capitalist countries to develop agriculture and increase grain output. At present, it is to cultivate high-quality and high-yield crop varieties, increase grain output at a faster speed, improve human famine caused by food shortage, and improve the increasingly damaged environment. With the rapid increase of population, the load of green agriculture has reached the critical line, so "blue agriculture" and "white agriculture" have become the focus of global attention.

Blue agriculture refers to the agricultural production of developing marine waters. Abundant marine resources are known as "the second granary of mankind in 2 1 century". If seaweed is processed into food, the annual output can be equivalent to more than 15 times of the total wheat output in the world today.

White agriculture is also called microbial agriculture or biological cell agriculture. The so-called "white" is mainly because there is no environmental pollution in its production process, which requires production in a clean environment. As early as 1000 years ago, farmers in China knew that planting beans can fertilize fields, land leisure can restore soil fertility, and crop rotation can reduce pests and diseases. They mastered technologies directly related to microorganisms such as fertilizer storage, fertilizer making, wine making, vinegar making and sauce making. With the development of science and technology, the role of microorganisms is more impressive. For example, with only 2% of the world's total oil production, 25-30 million tons of single-cell protein can be produced, which can feed 2 billion people 1 year; For another example, there are 500 million tons of crop straw in China every year. As long as 20% of the straw is fermented into feed, you can get 40 billion Jin of feed grain, which is equal to half of the national feed grain. It can be seen that "blue and white agriculture" is promising.