Characteristic Of Grape Anthocyanins And Its Application In Identification Of Pigment In Red Wine

In order to find the maximum physical and chemical factors on affecting color of anthocyanins, anthocyanins were extracted from grape skins by ultrasound assisted extraction, and then the effects of different physical and chemical factors on the stability of anthocyanins color were explored. The stability of the pigment from market and that from laboratory were compared. Meanwhile, The characteristic on coloration and its fundamental application of the anthocyanins of red wine were studied systemically by GB/T15038-2006 and HPLC method, NFQS02-2005, RM200 QC color value tester, UV visible spectrophotometer, revealing the characteristic on coloration under different p H values and oxidizing conditions, and illustrating the principle and regularities of characteristic on coloration under alkaline condition or exposes to the air for red wine and simulate wine prepared by artificial or nature. By combining the results of the studies above, a fast and simple method for identifying the pigment in red wine was established. More details are as follows:Firstly, the optimal conditions of extracting anthocyanins from grape skin were analyzed. They were as follows: 0.15% hydrochloric acid concentration of extraction solvent, 60% ethyl alcohol concentration of extraction solvent, extraction temperature 15 ℃, solid-liquid ratio of 1 g : 20 ml.Secondly, the effect of different factors on the anthocyanins stability were investigated. The results showed that p H value would change the structure and color of anthocyanins, hydrogen peroxide and the light are the biggest effects factor on the anthocyanins stabilities, temperature and sodium sulfite are less effects factor. The effect of sodium sulfite on anthocyanins is changed with the different concentration, low concentrations can improve the anthocyanins stabilities and high concentrations can reduce the anthocyanins stabilities. Preservatives, sugar, organic acid and metal ions are least factors affecting anthocyanins stability. Compare with anthocyanins from laboratory, anthocyanins from market have a stronger antioxidant capacity and ability of anti-light.Thirdly, the characteristic on coloration of red wine and simulate wine prepared by artificial or nature pigment under different p H values and oxidation conditions were revealed. The results showed that the color of simulate wine prepared by nature pigment and red wine changed from red to blue, with the increasing of p H values. while the color of simulate wine papered by artificial pigment was almost unchanged. red wine, Simulate wine prepared by artificial pigment or nature pigment have been oxidized to varying degrees with increasing of concentration of hydrogen peroxide. When the volume fraction of hydrogen peroxide was 8%, red wine reached the inflection point on oxidation. When the volume fraction of hydrogen peroxide was 40%, simulate wine with artificial pigment reach the inflection point on oxidation. The absorbance of simulate wine with artificial pigment have slight oscillations between 0.099 and 0.105, and the color simulate wine with artificial pigment keep red. So, the order of antioxidant capacity is as follow: red wine < simulate wine with nature pigment < simulate wine with artificial pigment.Fourthly, the optimum condition of preparation test paper was investigated. The 10 cm ×10cm qualitative filter paper is impregnated with 1.0% sodium hydroxide solution for 2-10 s. After the paper dried, there is a distance of 1 cm out of the edge of the paper should be snipped off. Then the rest paper is cut into 1 cm × 4 cm.Finally, a simple and easy method to identify artificial pigment or natural pigment in red wine was provided. Take a test paper, drip 2-3 drops of red wine on the test paper or remove out the test paper after dripping the test paper in red wine last 0.5 second, then observe the color of the test paper. If the test paper is red, then there is artificial pigments in red wine. If the test paper is blue and almost unchanged for 5 min exposed to the air, then there is nature pigment in red wine. If the test paper is blue and turns yellow gradually in 5mins, there is no artificial or nature pigment in red wine. This method is simple and fast, and it is suitable for the consumers to identify the pigment in red wine in daily life.