Preparation And Quality Evaluation Of Idesia Polycarpa Maxim Oil

Idesia polycarpa Maxim is a precious wild resource with high nutritional value and high linoleic acid,high vitamin E and phenolic substances.And it is cold-resistant,drought-resistant and barren-resistant.It is not only suitable for returning farmland to forests,but also has large fruit yield and good oil quality.It can fill the gap of edible oil raw materials in China and effectively alleviate the problem of edible oil supply in China.However,at present,there are still many problems in the production and processing of Idesia polycarpa Maxim oil,which have the disadvantages of imperfect production technology and poor quality of oil.Therefore,this study aims to systematically study the refining of Idesia polycarpa Maxim oil and evaluate its quality.The industrial production of Idesia polycarpa Maxim oil provides theoretical basis and technical guidance,and eases the pressure on China’s edible oil imports to ensure the safe supply of edible oil.(1)In this paper,the physical and chemical properties,including acid value,peroxide value,fatty acid composition,the nutrient content,such as polyphenol content,α-tocopherol,and the effect of antioxidant properties,containing antioxidant capacity and oxidative stability of Idesia polycarpa Maxim pressed oil were studied by drying fresh fruit of different temperatures,from 90 to 130℃.The optimum drying conditions were determined to be 120℃ and the drying time was 54.70 min.(2)The effects of degumming temperature,degumming time,degumming agent ratio and degumming agent volume on the residual amount of phospholipids in Idesia polycarpa Maxim oil were investigated.Based on the single factor experiment,four-factor and three-level response surface optimization experiments were carried out.The degμmming process conditions after optimization were: degumming temperature was 51℃,degumming time 35 min,EDTA-2Na concentration was 125 mmol/L,EDTA-2Na:SDS=2:1,under the above-mentioned process conditions,the phospholipid content of the Idesia polycarpa Maxim degummed oil was0.0102±0.0003%.(3)By comparing the decolorization methods,and investigating the effects of adsorbent type,adsorbent addition amount,adsorption decolorization time,adsorption decolorization temperature and heating decomposition temperature on the decolorization of Idesia polycarpa Maxim oil,the decolorization method determined after optimization for the adsorption-heating combined decolorization method,the adsorption decolorization process conditions were as follows: the adsorption decolorization temperature was 100℃,the activated clay addition amount was 3%(w/w),the adsorption decolorization time was 25 min;the heating decolorization process kept for 10 min at 200℃.Adsorption-heating combined with decolorization could completely remove chlorophyll,carotenoids and decolorizing oil from the Idesia polycarpa Maxim oil.The decolorizing oil as a whole had a clear,transparent yellow color.(4)The types and contents of volatile constituents of Idesia polycarpa Maxim oil were determined by electronic nose and GC-MS,and its characteristic odor components were identified.Among the many volatile components of Idesia polycarpa Maxim crude oil,the substance with the highest content and the greatest influence on the overall odor was(E,E)-2,4-nonadienal,so it was used as a reference for ROAV calculation.The substances with ROAV≥1 were(E,E)-2,4-heptadienal,(E,E)-2,4-decadienal,and the substances of 0.1≤ROAV<1 were(E)-2-Furfural,(E)-2-octenal,hexanal and 2-pentylfuran.As the refining process progresses,the odor substances contributing to the overall odor of Idesia polycarpa Maxim oil changed.The components that contributed to the overall odor in the degummed oil were:(E)-2-octenal,(E)-2-heptenal,(E,E)-2,4-hydradienal,2,4-nonadienal,hexanal,furfural and 2-pentylfuran;the main volatile components in alkali refining were:(E)-2-furfural,(E)-2-Octenal,(E)-2-nonenal,(E,E)-2,4-nonadienal,(E)-2-heptenal,2-non enal,2,4-anthracene dienyl,heptaldehyde,hexanal and 2-pentylfuran.The main volatile components in the decolorized oil were:(E)-2-furaldehyde(E)-2-octenal,(E,E)-2,4-decadienal,(E)-2-heptene aldehyde,2,4-nonadienal,2-decenal,hexanal and anti-α-ionone.In this study,the effects of water vapor deodorization,vacuum deodorization and extraction deodorization were compared.The effects of deodorant type and dosage,deodorization time,deodorizer mixing ratio and deodorization frequency on the deodorization of Idesia polycarpa Maxim oil were investigated.Optimized deodorization process conditions were: deodorizer was methanol and ethanol,deodorization time was 20 min,deodorized for 3 times,deodorizer(m L): oil(g)=2:1,methanol: ethanol=1:2.There were only three kinds of volatile components left in the deodorized oil.(5)After purification,the acid value,peroxide value and carbonyl price were reduced to 0.12mg/g,0.02g/100 g and 35.02meg/kg,reached the national food safety standard GB2716-2018.After decolorization,the content of chlorophyll and carotenoids was significantly reduced,and the oil exhibited a clear yellow color.During the whole refining process,the changes in the types and relative contents of fatty acids in Idesia polycarpa Maxim oil were small,indicating that the refining had little effect on fatty acid composition,and the fatty acid of Idesia polycarpa Maxim oil was highly unsaturated.The α-tocopherol content is relatively stable during the refining process,and only decreases during deodorization.The oxidation-induced temperature and oxidation induction time of the Idesia polycarpa Maxim oil decreased and shortened respectively during the process of degumming,deacidification,and adsorption decolorization,but after heating decolorization and deodorization,both the oxidation induction temperature and the oxidation induction time were increased and prolonged,because the removal of the thermally unstable substance improved the oxidation stability of the oil.The overall odor and volatile components of Idesia polycarpa Maxim oil in different refining stages were determined by electronic nose and GC-MS.The results showed that the main odor components of Idesia polycarpa Maxim oil were(E,E)-2,4-nonadienal,(E,E)-2,4-heptadienal,(E,E)-2,4-nonadienal,2-furfural,(E)-2-octenal,hexanal and 2-pentylfuran.After refining,the Idesia polycarpa Maxim oil had a very light smell and good quality.