Craft Optimization Of Ultrasonic-assisted Extraction Of Apple Polyphenols And Hemicelluloses From Apple Pomace

Fruit and vegetable juice industry has become one of the most important agricultural industry in the world, large numbers of fruit and vegetable pomace was produced as by-product in the fruit and vegetable juice industry. As a daily beverage, apple juice plays an important role in the production and processing of fruit and vegetable juice industry. Dried pomace is rich in functional substances, however most of the apple pomace resource has not been fully utilized nowadays, and most of the resource was used as animal feed or garbage waste, which not only caused great waste of resources, but also polluted the environment. Facing the status of pomace resource, in this study apple pomace was used as raw materials, assisted by ultrasound technology, apple polyphenols and hemicelluloses were extracted from apple pomace, the basic structure and physiological activity of apple polyphenols and hemicelluloses were researched. This study made the efficient use of apple pomace resource and enhanced the value of apple juice industry.This paper mainly including the following aspects:1. Optimized ultrasonic-assisted organic solvents(ethanol) extraction of apple polyphenols from apple pomace, investigated the influences of ultrasonic-assisted extraction(UAE) time, liquid-solid ratio and ethanol volume fraction on the yield of apple polyphenols.Optimized extraction parameters: UAE time of 24.78 min, 60.53% ethanol volume fraction and liquid-solid ratio of 34.96: 1(mL: g) and, the actual yield of apple polyphenols reached 1.357 � 0.09 mg/g under the optimized condition, closed to the predicted value.2. Optimized macroporous resin separation and purification processes of apple polyphenols, investigated antioxidant activity of apple polyphenols.AB-8 macroporous adsorption resin was chosen to purify apple polyphenols, 60% ethanol was used as as desorption solution and dissolvant, the adsorption and desorption time were 60 min, best apple polyphenols concentration of 0.092 mg/mL, adsorption velocity 2.0 BV/h and desorption velocity 3.0 BV/h. DPPH and HRSA method showed that the apple polyphenols extracted by ultrasonic-assisted method has strong antioxidant capacity.3. This part optimized ultrasonic-assisted extraction of hemicelluloses from apple pomace, investigated the influences of ultrasonic-assisted extraction time, liquid-solid ratio and alkaline hydrogen peroxide(H2O2) volume fraction on the yield of apple hemicelluloses.The optimized extraction parameter: UAE time 51.35 min, 6.51% H2O2 volume fraction, liquid-solid ratio of 42.73: 1(mL: g), the actual yield was 113.52�0.13 mg/g, closed to the predicted value.4. This part studied water holding capacity, oil holding capacity and swelling of hemicelluloses and pomaces. Antioxidant activity, infrared chromatography, thermal analysis method and gas chromatography were used to analysis the hemicelluloses.Research results showed that the extracted hemicelluloses has certain antioxidant capacity, the hemicelluloses extracted by ultrasonic-assisted alkaline H2O2 method composed of glucuronic acid, glucose, xylose, mannose, arabinose, rhamnose and galactose.