Bitter Almond Oil Extraction Process And Its Corrosion

China’s oil consumption is growing year by year with the rapid development of China’s economy.At present,China’s self-sufficiency rate of cooking oil is only about 40%.The yield of bitter almond increased year by year with the popularized of the policy of returning farmland to forest.The oil content of bitter almond was about 50%,and it is an important source of edible oil.But the bitter almond contains amygdalin will produce cyanide in the process of processing.And it will cause significant corrosion of the iron during the oil extraction.The reason for above that limited its promotion and application.In this study,bitter almonds were used as raw material to optimize the detoxification process,the extraction of bitter almond oil was optimized by SAAE,and the determination method of cyanide in bitter almond oil was established.At the same time,the reason of the corrosion of bitter almond oil on the iron was studied.The main results are summarized as follows:(1)In this study,bitter almond was detoxification used baking method,boiling method,microwave method and ultrasonic method.The effect of detoxification efficiency and detoxification technology on the physichemical properties of bitter almond oil were considered,and the orthogonal optimization was carried out by ultrasonic method.The detoxification rate was 97.59% when the ultrasonic power was 700 W,the ultrasonic treatment time was 30 min and the ultrasonic starting temperature was 20 ℃,and among the factors,ultrasonic power and ultrasonic treatment time had a significant effect on the detoxification rate.The physichemical characteristics of bitter almond oil were no significant change after ultrasonic treatment.(2)The present study describes the efficient salt-aided aqueous extraction(SAAE)of bitter almond oil and adopting RSM to optimize.The optimized concentration of sodium bicarbonate solution,solution-to-flour ratio,extraction time,and extraction temperature were found to be 0.4 mol/L,5:1,84 ℃ and 60 min,respectively,which corresponded to an oil recovery of 90.9%.The physiochemical characteristics of extracted oil can be suggested that the quality conforms the national standards.Moreover,the content of hydrocyanic acid(HCN)in bitter almond oil was found to be less than 5 mg/kg,which was lower as compared to otherreported methods.Results of micro-analysis indicated that SAAE leads to significant improvement in oil yield by allowing the release of oil and decreasing the emulsion fraction.Therefore,bitter almond oil extracted by SAAE is feasible.(3)A method for the determination of cyanide in bitter almond oil was established based on colorimetry.The results shown: the volume of HCl was 1.5 times of sample,the hydrolysis time was ≥120 min,the volume of distillation was 53% of the regent added,the time of distillation was ≥120 min,and relative standard deviations were <10%.And verify the method,the results of experiment were correlated with the results of predicted values,and the coefficient value was 0.92,so this method to determine the content of cyanide in bitter almond oil is feasibility.(4)The content of benzaldehyde and benzoic acid in crude bitter almond oil was higher than that of refined oil and oil extracted by SAAE.At the same time,content of cyanide in crude bitter almond oil is also much higher than the refined oil and oil extracted by SAAE.The concentration of iron ion,aluminum ion and zinc ion in oil increased by 428%,283%,43% respectively after adding KCN,and there was no significant change in concentration of magnesium ion and calcium ion.The concentration of iron ion,aluminum ion and zinc ion in the oil increased by 276%,500%,140%,respectively after adding benzoic acid.But the concentration of magnesium ion,and calcium ion did not change significantly after adding benzoic acid.When the content of benzoic acid is more than 1.0%,the cyanide content is more than 5 mg/L,prolonged contact will cause corrosion of iron products.Crude bitter almond oil is mainly through take the surface of the protective film of iron products off,thereby speeding up corrosion of iron,zinc and aluminum of the iron products,resulting in corrosion of iron products.