Technical And Stability Study On Extraction Of Pigment From Buckwheat Hull

Buckwheat hull has a great proportion in the buckwheat. Due to the differences of varieties and growing environment and the color of buckwheat hull also has differences. For example, gray bitter buckwheat hull, prolific from Yun Nan and Gui Zhou province. Brown bitter buckwheat hull, mostly found in Si Chuan, Gan Su province and so on. Black sweet buckwheat hull, prolific from An Hui, Inner Mongolia and others. In recent years, the basic composition of buckwheat hull, applications and development prospects have been widely reported. Because that the buckwheat hull contains polysaccharide, dietary fiber flavonoids compounds and many other kinds of components, by intensive research, scientists have found that buckwheat hull can purify oil in the water, which may solve pollution problems. Besides, buckwheat hull can act as a filler used in household items such as pillow mat, mattress and so on. The brown pigment in the buckwheat hull has stability to light, heat, sugars and metal ions and can be used in the production of candy, wines, cakes and other kinds of food and drinks. In the production practice, buckwheat hull can also be used as the raw material in making oxalic acid, which, can be widely used in pharmaceutical and organic industries. By this way, the byproducts of agricultural industry can be used effectively and also can gain economic benefits.Our country has a rich resource of natural pigments. Natural pigment exists widely in many organisms, mainly including plant pigments, animal pigments and microbial pigment. In recent years due to the reason of people’s physical health and the improvements of benefits of agricultural byproducts the requirement of natural pigments by consumers has been increased ever since. Along with the technological progress in food pigment, natural pigments will gradually replace artificial pigments. For example, lycopene has the function of anti-cancer, oxidation resistance and postpone senility.Turmeric pigment has the function of the anti-infection, anti-inflammatory and promoting blood circulation Zeaxanthin in the human body is a strong antioxidant, and has the function of anti-cancer, and preventing cataracts or cardiovascular disease. Therefore, research and development of functional pigment having medical and nutrient use will be of great importance.We use buckwheat hull as test materials and ethanol-extraction and ultrasonic extraction as experimental methods to extract pigments from buckwheat hull. We analyze the influence of light, temperature, pH value, sugar, metal ions, commonly used additive, antioxidants and reducing agent for the study of stability of buckwheat hull. This research provide a reasonable and effective use of pigments in buckwheat hull and a basis for development of functional pigments.The test results showed that the best experiment conditions in alcohol extraction are:material/liquid ratio,1:50, extraction temperature of80℃, soaks raises liquid density of70%, soaks raises time for2hours. In the experiment by ultrasonic extraction, the best extraction conditions are:material/liquid ratio with1:40, purified liquid concentration of75%and extracting time of6min By the study of different conditions in extraction of pigments in buckwheat hulls, we can get the result that with the proper light, temperature, additive agent, cane sugar and metal ions of Na+、Zn2+、Mg2+、K+、Ca2+, we can get the buckwheat hull pigments with good stability.