Study On Preparation Of Hydroxy Tyrosol From Olive Pomace And It's Vitro Antioxidant Activity

Longnan,Gansu Province,as the main olive crop producing area in China,is also the main producing area of edible olive oil.Every autumn,olive pomace abandoned after olive picking and processing.These pomaces contain abundant active substances,which can be recycled as industrial raw materials,food,cosmetics and other additives.This olive pomace have a lot of economic value.It hasn't been fully utilized.Traditionally,a small amount of olive pomace is generally used as an additive ingredient of livestock feed.However,these huge amount of olive pomace after process of extracting olive oil is actually stored in the open air and accumulated mostly,which emits an unpleasant odor after microbial fermentation.It not only causes a lot of waste of effective resources,but also causes the environment Pollution.How to properly handle these olive pomace is a major problem faced by olive oil production and processing enterprises.This experiment provides a new way for enterprises to recycle olive pomace by recovering a kind of active ingredient in olive pomace,named hydroxy tyrosol.The waste olive residue from Longnan olive oil production enterprise was divided into liquid and solid components in this experiment.Established a method which based on Ultra-high performance liquid chromatography(UPLC)for separation and determination of polyphenols in olive residue The experiment also established a Folin phenol colorimetry which was used to determination of total phenols.The contents of hydroxy tyrosol,olivopicrin and total phenol in the wastewater of the miracle olive residue were determined by the above two methods.The results showed that the retention time of hydroxy-tyrosol and olivopicrin were 3.319 min and 13.387min,and the average contents of the three were about 208 mg/kg,324 mg/kg and3780 mg/kg.These two components using macroporous resin enrichment and direct hydrolysis to extracting total polyphenols and hydroxy tyrosol from olive residue.A pretreatment process for enriching polyphenols in olive wastewater by alkaline hydrolysis solid olive residue-D101 macroporous resin was established.In the hydrolysis part,sodium hydroxide solution was used to hydrolyze the solid part of olive pomace in water bath,the concentration of sodium hydroxide solution was 0.31mol/L,the water bath time was 23 minutes,the water bath temperature was 80.5?,and the ratio of material to liquid was 1:28.Under these conditions,the yield of hydroxy tyrosol was 837 mg/kg,and D101 macroporous resin was used for the dynamic adsorption-desorption part.The optimum adsorption-desorption conditions are 12 g resin,sample volume 120 mL,sample concentration 3780 mg/L,adsorption flow rate 1 BV eluent 80%ethanol aqueous solution,eluent Volume 45 mL,elution rate 1 BV,63.7%polyphenols in olive wastewater can be recovered.Each liter of olive wastewater can recovered about 2400 mg olive polyphenols.The conversion rate of hydroxy tyrosol was 30%,and the total yield of hydroxy tyramol from olive pomaces was 818 mg/kg.The crude hydrolysate of hydroxy tyrosol was purified by ethyl acetate extraction.The purity of hydroxy tyrosol was 66.81%that increased 3.7 times compared to initial.The antioxidant activity of purified hydroxy tyrosol was tested by DPPH,ABTS and hydroxyl radical methods.The results showed that the antioxidant capacity of hydroxy-tyrosol preparation solution for DPPH·was worse than gallic acid and ascorbic acid,but for ABTS·and·OH,the scavenging capacity was 2.53times and 1.88 times of gallic acid,7.17 times and 4.39 times of ascorbic acid,and there was a close correlation between them.Based on the comparison of retention time and spectra,a triple-relocation method was established for the preparation by ultra-high performance liquid chromatography-tandem mass spectrometry.Comparing the mass spectra of molecular ions and fragments of standard and preparations,the final product was ensured hydroxy tyrosol.The results of methodological investigation showed that there was a good linear relationship between olivopicrin and hydroxy-tyrosol in the range of 5 mg/L-1000 mg/L,R~2<0.9995,RSD of stability,intra-day precision and inter-day precision were all below 2%;the recovery of target substances in high,medium and low concentrations was indicated by the method.The rate is above 95%,RSD<4%,which is in line with the practical application requirements.