| In the processing industry of apricot kernels,removing the kernels skin is the first indispensable procedure due to its influence on the color,quality and commercial value of the processed products,and debitterizing is the second step due to the high content of amygdalin(a potentially toxigenic compound).Some water-soluble substances in the apricot kernels such as protein,amygdalin and polyphenols are also transferred to the water under the condition of skin removing and debitterizing,thus causing great loss of nutritional compounds and weights for the apricot kernels,simultaneously bringing about the environmental problems if directly discharged.The wastewater is discharged into the sewage treatment system,and the active substances are not used at present.Considering the above-mentioned aspects in production,the aim of this study was to analyze the compositions,the phenolic profiles and antioxidant capacity of the by-products recycled from the peeling/blanching and de-bitterizing wastewater during the processing of apricot kernels,combined with modern separation methods to recycle the amygdalin.The main purpose was to verify the byproducts' potential for utilization,improve its added-value and reduce the pollution to the environment in the apricot kernels processing industry.The main results of this research are as follows:1.Analyze the compositions and the phenolic profiles of the by-products recycled from the peeling/blanching and de-bitterizing wastewater during the processing of apricot kernels.The present study demonstrated that the by-products obtained from the industrial processing of apricot kernels contain a great amount of bioactive compounds,such as protein,polysaccharides,amygdalin,phenols and so on.Three antioxidant evaluation methods(reducing power,Hydroxyl radical and DPPH-radical scavenging capacity)and principle component analysis(PCA)results shows that the strong antioxidant capacity of the by-products including the reducing power and the scavenging effect on DPPH· and OH· free radicals.In addition,the antioxidant capacity highly correlated with the identified phenolic compounds as shown in the PCA figures.2.It was indicated that the macroporous resin of XDA-1 was the suitable resin for adsorption to amygdalin.The result shows that the adsorptions by XDA-1 resin for amygdalin is exothermic adsorption process,can be carried out spontaneously at room temperature and has physical adsorption characteristics,The Freundlich adsorption law is applicable to the adsorptions of amygdalin on XDA-1 adsorbents within the concentration in our study;The results for dynamic adsorptions shows 80%ethanol was the suitable de-adsorption solvent,it was good for attaining the adsorption equilibrium at the concentration of 78.05 mg/mL,with the resin of XDA-1,the purity of amygdalin,determined by HPLC,was increased from 34.04%to 61.58%,with 88.75%average recovery.3.Several aqueous two-phase such as EtOH/(NH4)2SO4 ware formed using the ethanol as salts phase substances.The formation,properties and extraction characteristics were studied and compared in detail for several systems mentioned.EtOH/(NH4)2SO4 could form fastly to stable in the wide phase range,and extract amygdalin to the top phase containing ethanol with higher extraction rate.The experiments of optimum extraction conditions were perfomed.The results shows that the optimum extraction conditions were 18%of(NH4)2SO4 and 30%of ethanol,pH=7,35? of temperature.The extraction rate of the amygdalin was 90.37%,Using the EtOH/(NH4)2SO4 system to extract amygdalin,The results indicated that the the purity can increase from 32.82%to 68.44%. |
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