| Camellia oleifera seed oil is known as"oriental olive oil",which is rich in unsaturated fatty acids,also contains squalene,vitamin E,sterols,flavonoids and other active substances,is C hina's unique woody oil.In recent years,due to the intensification of the contradiction between supply and demand of edible oil market in China,camellia oil products are increasingly supported by the government and consumers,camellia acreage grow rapidly,camellia oleifera seed production increased year by year,and thus the processing of camellia oleifera seed more and more important.In this paper,the fresh camellia oleifera fruit was studied by retting,and the oleifera oleifera seed was used as the object,heat pump drying and microwave heat treatment were carried out to study the heat pump drying characteristics of camellia oleifera seed,and a scientific and reasonable heat pump drying model was established.The process conditions were compared with the three kinds of hea t treatment methods such as roasting,baking and wet steam.At the same time,camellia oil was prepared by ancient method,spiral and hydraulic pressure,and the effects of different pressing techniques on the quality of camellia oil and camellia oleifera seed meal,aiming at providing the data support for the application of new technology in the processing of camellia oleifera seed,and to provide the theoretical basis for improving the processing technology of camellia oleifera seed.The main research contents and results are as follows:(1)Study on the retting of camellia oleifera fruitsIn order to find the appropriate heap conditions and time to improve the oil rate,the changes of the main components of camellia oleifera seed and the quality of camellia oil were researched after the retting of camellia oleifera fruits in the constant temperature and humidity conditions and natural conditions.The results showed that:the retting was conducive to improve the oil content.The maximum oil content could reach 45.89%after 5days under constant temperature and humidity conditions,and the maximum oil content could reach 45.01%after 7 days under natural conditions.The content of total sugar in the two conditions showed a decreasing trend,and the protein content remained at 17%~15%.The acid value and the peroxide value of camellia oil were between 0.50~0.78 mg/g and0.38~0.80 mmol/kg respectively.The result of correlation analysis showed that there was a significant negative correlation between crude fat and total sugar content.The consumption of carbohydrate was the basis of the synthesis of oil.The optimum retting times of two contions were 5 days and 7 days.(2)Study on the heat pump drying of camellia seedIn order to improve the drying efficiency and reduce the energy consumption,the characteristics of heat pump drying for camellia oleifera seeds under different temperature and relative humidity were studied.Drying curves were fitted by seven kinds of drying mathematical models and the BP neural network model.The results showed that the deceleration stage was the main stage in the process.The higher the drying temperature and the lower relative humidity,the shorter drying time and the greater effective water diffusion coefficient would be.The activation energy of camellia oleifera seed was 32.01KJ/mol.The Midilli model was the optimum mathematical model describing the process of heat pump drying of camellia oleifera seed,and the average relative error between the theoretical va lue and the experimental value was 8.97%.The fitting degree(R~2)of BP neural network model was more than 0.999,and the average relative error between the simulation results and the actual values was 4.57%,which indicated the BP neural network model was more accurate than the Midilli model in predicting the moisture content during the heat pump drying process.Compared to natural,hot air,vacuum and frozen four drying methods,heat pump drying needed shortest time and lowest energy consumption,it also had a little impact on the quality of camellia oil.(3)Study on the heating treatment of camellia seedThe effects of microwave treatment conditions on the extraction rate of oil and the qualities of camellia oil were studied.For the optimization of the microwave treatment process,an orthogonal test was designed on the basis of single factor experiments.The results showed that the moisture content of camellia oleifera seeds,microwave power density and microwave treatment time had a certain impact on the residual oil rate,the physical and chemical indexes and the content of nutritional function ingredients.The yield and quality of oil are high and good when the microwave treatment conditions were as follows:the moisture content of camellia oleifera seeds is between 11%and 13%,microwave power density is between 3 W/g to 5 W/g,and microwave treatment time is between 4 min and 6 min.In order to explore the suitable heating treatment process of camellia oleifera seed,microwave,roasting,baking and steaming,four different heating methods were used.Yield efficiency of seeds and the quality of oil were determined.Fuzzy mathematical evaluation method,gray correlation method and principal component analysis were used to make a comprehensive evaluation.The results showed that the four methods could significantly improve the yield efficiency of seed and the sensory quality of oil.The storage stability,volatile components and content of nutrition functional ingredients in oil such as flavone,polyphenol,sterol and so on also increased.There has little effect on fatty acid composition of oil.Acid value and peroxide value increased slightly,but still conform to the requirements of the national first-degree standard.In general,microwave is the best,and the effects of roasting,baking and steaming are relatively small.(4)Comparative study on the method of pressingFor the purpose of exploring the appropriate processing methods of camellia oil,the effects of different pressing methods on the quality of camellia oil were analyzed.The results showed that the pressing method could significantly affect the sensory quality,characteristic index,physical and chemical indexes,nutritional function components and storage stability of camellia oil,however,the impact on the fatty acid composition was small.The oil obtained by the ancient method had the best sensory,physical and chemical quality,storage stability and the highest nutritional value.Camellia oleifera seed meal is the byproduct which has a huge development and utilization value.The residual oil rate and the main components of camellia oleifera seed meals were determined.The results showed that the residual oil rate of the meal obtained by the ancient pressing method was the lowest.Pressing methods had significant effects on the content of protein,total sugar,reducing sugar,tea saponin,polyphenol and flavonoids in the seed meals,however,all of these were highest in the meal obtained by the ancient squeezing method.Not only that the functional characteristics of the protein extracted from the meal obtained by the ancient method was better than the other two methods.Taking into account the quality of camellia oil and camellia oleifera seed meal,the ancient pressing method was a better method for processing camellia oil. |
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