| Camellia seeds contain oil,starch,saponin,polysaccharide,protein and flavonoids,etc.Camellia seed oil extracted from Camellia seeds has high oleic acid content and is rich in sterols,squalene,vitamin E and polyphenols and other active ingredients,which have high edible value.It was found that the shelling rate,storage conditions and compounding process would affect the quality characteristics of Camellia seed oil.In order to improve the quality of Camellia seed oil,this study was conducted using Camellia seeds as raw material,the Camellia seeds were pressed at different shelling rates and the quality indexes of Camellia seed oil with different shelling rates were analyzed.The Camellia seed were stored under refrigeration and room temperature conditions,and the quality indexes of oil contained in Camellia seed under these two storage conditions were analyzed.The Camellia seed oil was refined,and the oxidation stability of Camellia seed oil at different refining stages was measured,and the Camellia seed oil with the strongest oxidation stability was compounded with the refined oil,and the quality analysis of Camellia seed oil with different compounding ratios was performed.The main results were as follows:1.Using camellia seeds as raw material,we investigated the effects of shell content on the quality characteristics of screw-pressed camellia seed oil,including oil yield,physicochemical index,bioactive substances,fatty acid composition,oxidation induction time,and volatile flavor components.The results indicated that as the shell content increased,the oil yield of the screw press increased and stabilized at 20% shell content,with the highest oil yield reaching 26.29%.In addition,when the shell content was 20%,Camellia seed oil showed the lowest acid value,peroxide value,and moisture and volatile matter content,which were 0.82 mg/g,0.37 mmol/kg,and 0.07%,respectively;Camellia seed oil showed the longest oxidation induction time of 22.62 h.Meanwhile,its colour value and phospholipid content were at a low level.The highest polyphenol content of 67.48 mg/kg was found when the shell content was 30%-40%,and the colour of the oil was relatively dark.There was nosignificant effect of shell content on the sterols content,squalene content,vitamin Econtent,and fatty acid composition of Camellia seed oil.Electronic nose and GC-IMS were used to analyze the volatile flavour components in the oil.The results showed that the main volatile compounds in the oil were aldehydes,alcohols,esters,ketones,and heterocyclic substances,and there were significant differences between the volatile components in the oil with higher shell content rates and those with lower shell content rates.When the shell content was less than 20%,the oil contained more volatile components and had a stronger aroma,and as the shell content increased,the volatile content in the oil decreased.2.We investigated the influence of storage temperature on the quality characteristics of the oil contained in the camellia seeds during storage by storing the camellia seeds under refrigeration(4 ℃)and at room temperature,respectively.Our findings show that storing the camellia seeds under refrigeration resulted in stable and low acid value of oil at 0.31mg/kg during storage,whereas the peroxide value of oil in refrigerated camellia seeds after five months of storage was 0.40 mmol/kg,significantly lower than that of camellia seeds stored at room temperature.Additionally,after two months of storage,the squalene content of oil in refrigerated camellia seeds was 166.69 mg/kg,significantly higher than that of camellia seeds stored at room temperature.The polyphenol content of oil in refrigerated camellia seeds was significantly higher than that of camellia seeds stored at room temperature during the first two months of storage.After one month of storage,the sitosterol content of oil in refrigerated camellia seeds was 767.26 mg/kg,compared to only 638 mg/kg under room temperature conditions.The vitamin E content of oil in camellia seeds showed a decreasing trend with the extension of storage period,but there was no significant difference in the vitamin E content of oil in camellia seeds under different storage temperatures.The fatty acid species of oil in camellia seeds were not affected by the storage temperature;however,the percentage of linoleic acid in camellia seeds stored under refrigeration for two months was 9.86%,higher than the 9.42% at room temperature.3.The oxidation stability of the oil was measured by different refining degrees of Camellia seed oil,and the results showed that the oxidation induction time of degummed oil was the longest,30.29 h.The content of squalene,sterols,vitamin E and polyphenols in degummed oil was significantly higher than that in refined oil.The oxidation stability was measured by compounding degum oil and refined oil in different proportions,and the results showed that the oxidation induction time was 25.24 h when the percentage of degum oil was 10%,which was significantly higher than that of the refined oil(21.92 h),and there was no significant difference between the oxidation stability of different compounding proportions of Camellia seed oil when the percentage of degum oil was lower than 40%,and when the percentage of degummed oil reached more than 40%,the oxidation stability of compounded oil started to increase.In summary,in order to obtain high quality oil of Camellia seeds,low temperature storage Camellia seeds can be used to make oil by pressing under the condition of 20% shell content,and the oxidative stability and nutritional quality of oil can be further improved by compounding refined oil and degummed oil.The research results will provide a theoretical basis for enterprises to produce high-quality Camellia seed oil. |
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