Degradation Kinetics Of Defatted Oil Palm Mesocarp Fiber In Sub-critical Water And The Antioxidant Of Products

The study of oil palm fruit mesocarp that is a co-product of oil palm fruit after shelling and oil extraction is almost blank. The researches of oil palm fruit are mainly concentrated on the palm oil in our country. In order to better use of agricultural and sideline products, develop new materials of energy. In present, the degradation kinetics of oil palm fruit mesocarp by means of the hydrolysates in sub-critical water was studied. The active ingredients in empty fruit bunch extracted by sub-critical water, ultrasonic-assisted and reflux method were studied, obtained the corresponding extractive. The antioxidant activity of those extractions was assessed by5kinds of antioxidant system. The effects of liquid ratio, extracting temperature and time on the extraction amount of polyphenols extracted by sub-critical water were studied, and the optimum extraction parameters were confirmed by response surface methodology. The antioxidant activity of extractions from oil palm fruit mesocarp in Sub-critical water was studies. The morphologic changes of degradation residues were investigated, the best extraction conditions of different target products were found out, and the mechanism of sub-critical water degradation (extraction) was explored by the above studies. The specific studies and results were as follows:1. To clarify the degradation kinetics of oil palm fruit mesocarp in sub-critical water, the degradation process yield of reducing sugar was studied for different degradation conditions, establish the corresponding kinetic model. It turned out that the pathway of oil palm fruit mesocarp fiber degradation in sub-critical water could explain by the Seaman model. The yield of reducing sugar was affected significantly by the degradation temperature and reaction time in sub-critical water. The activation energy of oil palm fruit mesocarp fiber degradation was49.48kJ/mol, the reducing sugar was62.68kJ/mol corresponding. The stability reducing sugar was produced at180℃for30min in this degradation process.2. In this study, the contents of xylose, furfural and PH in the degradation were determinate in sub-critical water, during the different temperature and time. The results show that the catabolites were varying by time and temperature during the degradation of sub-critical water. The xylose was518.8mg/L which produced at180℃for30minutes similar to the furfural was352.9u g/L which created at220℃for10minutes during the degradation of sub-critical water from oil palm fruit mesocarp. Therefore, the products which based on demands could manufacture by adjusted temperature and time in sub-critical water.3. Author selected three kinds of methods to extract the antioxidant activity constituent of oil palm fruit mesocarp. The results of the activity of extractions by different extracted methods were evaluated by5kind’s determination methods of antioxidation coincide exactly with the results. The antioxidant activity of extractions were sub-critical water extraction> hot reflux extracts> ultrasonic extract. The polyphenols content extracted by sub-critical water was6.1times to ultrasonic assisted extraction,5times of refluxing extraction from oil palm fruit mesocarp.4The effects of liquid ratio, extracting temperature and time on the extraction amount of polyphenols extracted by sub-critical water were studied. And the response surface analysis was used to optimize the technological conditions for polyphenols extraction from oil palm fruit mesocarp in sub-critical water. The optimum conditions were liquor to material50mL/g,40minutes,250℃by response surface methodology. Under the optimum operating conditions, the optimal predicted extraction percentage of polyphenols was6.26g/100g.This was of great theoretical significance in guiding the subsequent research on polyphenols manufactured in sub-critical water from oil palm fruit mesocarp.5To study on the antioxidant activity of extractions from oil palm fruit mesocarp in Sub-critical water. The polyphenols was abundant in extractions of ethyl acetate, is almost double what those in water extraction, barely in n-butyl alcohol. The antioxidant activity of all extractions was positively correlated to the content of polyphenols. The antioxidant activity of extractions of ethyl acetate were inferior to ascorbic acid, but superior to the extractions of sub-critical water which indicated that the antioxidants from oil palm fruit mesocarp were mainly polyphenols which could enrich by ethyl acetate.6The morphology of residues after degradation in sub-critical water from oil palm fruit mesocarp was studied. Calculate the liquefaction yield of oil palm fruit mesocarp in sub-critical water at140℃to260℃. Morphological changes of residues were observed. The hydrolization means the status of material had changed solid into liquid was extended by the rise of temperatures and the increase of liquefied rate. Scanning electron microcopy images showed that different physical forms of hydrolytic residues caused by different conditions the damage of structure of fiber in oil palm fruit mesocarp was remarkable to the temperature in sub-critical water.