Study On The Extraction Of Hazelnut Shell Brown Pigment And Study Of Its Antioxidant Acticity

In order to make proper use of by-products of hazelnut shells and produce high value-added products such as brown pigment,this paper adopted ultrasound-assisted organic solvent method to extract and purify brown pigment of hybrid hazelnut shells,and the freeze-dried powder samples of hazelnut shell brown pigments were obtained.In addition,the stability of the hazelnut shell brown pigments was examined and the functional groups of brown pigment were analyzed through the antioxidant experiment in vitro and the Fourier infrared spectrum.Through these studies,it helps to lay a scientific theoretical foundation for the further investigation and application of the brown pigment of hybrid hazelnut shells in future.The ultrasound-assisted ethanol extraction method was utilized to extract the brown pigment of the hybrid hazelnut shell,and the response surface experiments and variance analysis were adopted to optimize extraction process parameters.The optimal extraction conditions of the brown pigment of hazelnut shell were obtained as follows:the extraction temperature was 61°C,the ultrasound time was 34 min,the liquid-solid ratio was 24:1?m L/g?and the ethanol concentration was 63%.The absorbance under the condition was 0.5604±0.01 and the color value was 32.07.The results of purification experiment showed that the purification of X-5 macroporous resin was preferable than other methods.The parameters of static adsorption and desorption test were as follows:the adsorption time was 4h,the mass concentration of sample solution was 25mg/m L,the p H value of sample solution was 5,the desorption time was 3h,the ethanol concentration was 70% and the p H value of ethanol solution was 4.As for the dynamic adsorption-desorption test,the parameters of the optimum technological conditions were obtained as follows:the mass concentration of the sample solution was 25 mg/m L,the flow rate was 2.0 mg/min,the ethanol concentration was 70%,the eluting velocity was 2.0 mg/min,and the color value of the purified sample increased from 32.07 to 52.05 after purification.The antioxidant activities of brown pigments and Vc were determined by FRAP methodand·OH and ABTS+·scavenging.The results showed that the higher the concentration of brown pigments was,the stronger of scavenging and reducing ability was.The color reaction and FTIR analysis showed that the brown pigments of the hazelnut shells were flavonoids,and the phenolic hydroxyl groups were the main groups of the antioxidant properties.In addition,functional groups including C=O,C=C,C-O and =C-H were also beneficial to its chemical ability.The stability study found that brown pigment of hazelnut shells could be easily dissolved in the polar solvent such as distilled water,alkali solution,acid solution,ethanol and acetic acid.Furthermore,brown pigment could be stored at room temperature and the acid condition had little influence on it.In addition,brown pigment was stable under the conditions of dark,indoor natural light and outdoor sunlight,K+,Na+,Mg²⁺ and Ca²⁺.However,brown pigment should be avoided to contact with Zn²⁺,Fe³⁺,Al³⁺and Cu²⁺in the industrial production and storage and high volume fraction of oxidant had a certain fading effect on brown pigments.Finally,reducing agent,sodium sorbate,glucose and sucrose were stable to brown pigments.