Studies On Extraction, Purification And Antioxidative Effect Of Brown Pigment From Chestnut Shell

With the improvement of our life and personal consciousness of health care, we pay more and more attention to food security. It is confirmed by toxicology and analytic technology that many synthesized pigments are harmful, and some of them can even cause cancer. So they are prohibited from being used in food industry.Natural pigments,which are safe and functional, are now widely concerned, and become a research focus.Brown pigment can be extracted from Castanea mollissima shell which is the castoff processed chestnut. The pigment is worthwhile being investigated and applied by virtue of its good water-solubility,stability and high color value.The technological conditions for ultrasonic extraction of pigment from chestnut shell was studied. The effects on the extraction yield of extractant, extracting time, extracting temperature, ultrasonic power,the ratio of solid to solvent and extracting times were studied.Orthogonal test was carried out , and the optimum technological parameters of ultrasonic-assisted extraction were as followed: extracting temperature 70℃,time 90min,ratio of solid to solvent was 1:15,ultrasonic power was 500W and extraction times was two. Extracting temperature and time among them were notable. With ultrasonic method, the extraction yield could reach 11.64%. Compared with the traditional method, ultrasonic extraction of pigment from chestnut shell had the advantages of short time, high efficiency and high yield.The adsorption and desorption of the brown pigment from chestnut shell with macroporous adsorption resin were studied.The results showed that among 11 types of macroporous adsorption resin,the DA-201 was the best for adsorbing and separating the brown pigment from chestnut shell under the following technological conditions: pH5, the concentration of the pigment sample was 2.0mg/mL, the flow rate of adsorption was 1.8mL/min, wet resin showed an adsorbing capacity of 19.5 mg pigment per gram, the eluent was 80% ethanol, recovery rate of the pigment was 75%. The DA-201 resin could be used 5 times repeatedly. The colour value and the content of total flavonoids of the pigment by this method were increased 74.1% and 17.8% respectively.Effect on scavenging active oxygen radicals of rough and purificatory pigment from chestnut shell was studied.The results showed that the brown pigment had scavenging effects on hydroxyl radical,superoxide anion radical and aliphatic radicals on lipid-peroxidation. In the range of test concentration, the maximum scavenging or inhibition rate of the brown pigment to hydroxyl radical generated by Fenton reaction,superoxide anion radical generated by illuminating riboflavin system and linoleic acid auto-oxidation was 83.0%, 83.6% and 88.5% respectively. The results suggested that the brown pigment from chestnut shell was an excellent natural antioxidant and free radicals scavenger.The results can provide theoretical basis and technology parameters for the extraction of natural brown pigment from castanea mollissima shell,and the application in food,medicine,and cosmetic and so on.And it also provided a new method to utilize the castoff of processed chestnut.