Study On The Refining Technology And Quality Of Bitter Almond Oil

Bitter almond,also known as North almond,is a food resource with high nutritional value.Its protein and amino acid composition are reasonable;its fat content is close to 50%;mineral elements and vitamins are mainly calcium,iron and potassium.Bitter almond has the effect of reducing breath,relieving asthma and relieving cough.It can effectively prevent atherosclerosis and reduce blood lipid.Bitter almond oil has a high content of unsaturated fatty acids and is widely used in food,chemical industry and cosmetics.In this study,the degumming,deacidification and decolorization conditions of bitter almond oil were optimized by measuring the dynamic changes of physical and chemical indexes of oil before and after refining,analyzing the quality and oxidation stability of oil.At the same time,the essential oil of bitter almond was extracted from bitter almond cake,the components of the essential oil were explored,and the antioxidant activity in vitro was analyzed,so as to provide theoretical reference for the further processing of bitter almond.The results are as follows:1.Based on the single factor experiment of water addition,degumming temperature and degumming time,three factors and three levels response surface optimization analysis was designed to explore the optimal process of hydration degumming of bitter almond oil,and to analyze whether the fatty acid composition of oil changed before and after degumming process.The results showed that the optimum conditions for degumming of bitter almond oil were as follows:water content was 3%of oil weight,temperature was 60 C,degumming time was 30 min,and degumming rate was 76.87%.GC-MS analysis showed that the composition and relative content of fatty acids remained unchanged before and after degumming.2.Combining single factor test and response surface analysis,the process conditions of alkali refining deacidification of bitter almond degunming oil were optimized,and the fatty acids of bitter almond oil before and after deacidification were analyzed and compared to explore whether the deacidification process affected the composition change.The results showed that the optimum conditions for alkali refining deacidification of bitter almond oil were 30 minutes of deacidification time,0.25%super alkali content,9.5%NaOH content and 89.42%deacidification rate of bitter almond oil.The composition of oil is basically unchanged before and after deacidification,mainly unsaturated fatty acids,indicating that the alkali refining deacidification process has no effect on the composition of fatty acids.3.The process of alkali refining deacidification of bitter almond degumming oil was optimized.The single factor variable deacidification time,super-alkali content and NaOH mass fraction were set.Combining with single factor test and response surface analysis,the results showed that the optimum conditions for alkali refining deacidification of bitter almond oil were 30 minutes,0.25%super-alkali content,9.5%NaOH mass fraction and 89.42%deacidification rate of bitter almond oil.The composition of oil is basically unchanged before and after deacidification,mainly unsaturated fatty acids,indicating that the alkali refining deacidification process has no effect on the composition of fatty acids.4.After degumming,deacidification and decolorization of crude oil,the physicochemical indexes of bitter almond oil,such as color,transparency,taste and acid value,were compared before and after refining.The fatty acid composition and relative content of bitter almond oil were analyzed by gas chromatography-mass spectrometry(GC-MS).The oxidation stability of bitter almond oil was determined by oven acceleration method.The results showed that the physical and chemical indexes of the refined oil of bitter almond were better than that of crude oil;the overall composition of fatty acids remained basically unchanged before and after refining,and the proportion of unsaturated fatty acids to total fatty acids was close to 95%.At the same time,the change trend of peroxide value and conjugated diene value showed that the oxidation stability of bitter almond oil decreased after refining.5.With degreased bitter almond cake as raw material,the essential oil of bitter almond was collected by self-made steam distillation equipment in laboratory,its composition was determined,and its antioxidant activity in vitro was explored.The results showed that there were 12 components in the essential oil extracted from degreased bitter almond cake,including benzaldehyde(73.8%),benzylethanonitrile(22.43%),benzoic acid(2.30%)and benzyl alcohol(0.52%).DPPH and ABTS free radical scavenging test were used to detect the antioxidant activity of Bitter Almond Essential Oil in vitro.The activity was proportional to the concentration of essential oil.