Extraction Of Polyphenols From Walnut Byproduct And Its Influence On The Stability Of Lipid Oxidation

Natural antioxidant will replace synthetic antioxidant in the food industry in the future,so antioxidant research will still focus on developing practical,efficient and low-cost natural antioxidant.In recent years,as China adjusts agricultural industrial structure,it has become instant to make the mass production of walnut oil considering the forestry and fruit industry develops rapidly.And it is urgent to study and solve the problem that natural antioxidants replace synthetic antioxidants.To comprehensively apply Xinjiang walnut in a higher level through modern high-tech technology and turn waste into wealth can provide theoretical basis for walnut development.In order to make clear external antioxidant activity of different walnut parts and improve walnut comprehensive development and utilization,this research extracts the polyphenols substance and flavones substance from different walnut parts through different solvents,optimizes the ways to extract the polyphenols substance and flavones substance,measures their content,and evaluates the total external antioxidant activity based on the elimination of DPPH free radical and ABTS free radical.According to the results,the polyphenols substance and flavones substance in different walnut parts were respectively0.838-53.89 mg/g and 0.07-0.997mg/g in content.Among them,walnut diaphragm contained the highest polyphenols and flavones and antioxidant activity,followed by walnut capsule.Walnut shell was with the lowest.Based on the correlation analysis,in addition to walnut kernel,other walnut parts focused on polyphenols and flavones in anti-oxidation,and the polyphenols and flavones content were positively correlated with antioxidant activity.Different walnut parts were with rich polyphenols substance,so it was feasible to develop different walnut parts into new functional food.The research extracts polyphenols from walnut peel,capsule,diaphragm,and shell and adds them to walnut oil at different ratios,and screens out the best additions and addictive amount according to the POV change in walnut oil during the storage period.It discusses the oxidation stability of walnut oil under the condition of adding different antioxidants through Schaal oven accelerated method.It studies the influence of antioxidants extracted from different walnut parts on the oxidative stability of walnut oil based on thedetermination of oxidation value,acid value and iodine value,the change in refractive index,relative density,chromaticity,conjugated diene,conjugated triene,fennel value,fatty acid and VE content,and the comparison of walnut oil without any antioxidants and synthetic antioxidant TBHQ,and thus infers the storage period of oil products.According to experimental results,polyphenols in walnut capsule,diaphragm,and peel were superior to those in walnut shell.If a certain amount of polyphenols substance was added to walnut oil,peroxide value and acid value in walnut oil increased at a slow pace as time went on.The test results about other indexes also showed TBHQ,Peel polyphenols diaphragm polyphenols,capsule polyphenols,and blank comparison were in sequence in antioxidant activity from high to low;the shelf life of walnut oil with additional 0.05 %walnut peel polyphenols was extended to 6.5 from 4 months.