| Phoenix tree(also named Firmiana or tung ma) is a famous street and courtyard viewing tree. The seed of phoenix tree has many medicinal value, which has often been used as traditional C hinese medicinal material. The oil content of phoenix tree seed is high, which make it become a new kind of woody oil resource. Therefore, the physical and chemical properties, the trace constituent, the composition of fatty acid and the structure of triacylglycerols of phoenix tree oil were investigated in the paper, and the effect of different origins and extraction method were also compared. Secondly, the kinetics and thermodynamics of oil extraction from phoenix tree seed using n- hexane were studied. Finally, Lipozyme TLIM was used as catalyst to prepare the fatty acid of phoenix tree oil using different hydrolysis methods, which can give some advices for fast preparetion of the fatty acid from phoenix tree seed.(1)Phoenix tree seeds from Jiangsu and Anhui were used as raw materials in the study. For phoenix tree seed from Jiangsu, the contents of moisture, ash, crude protein, crude oil were 7.45±0.17%, 4.39±0.02%, 19.67±0.36%, 27.80±0.34%, respectively. For phoenix tree seed from Anhui, the contents of moisture, ash, crude protein, crude oil were 7.12±0.32%, 4.44±0.13%, 19.23±0.45%, 24.97±0.42%, respectively. Using ultrasonic extraction of phoenix tree seed from Jiangsu, the acid value, peroxide value, saponification value, unsaponifiable matter content of phoenix tree seed oil were 2.37±0.42mg/g, 1.54±0.12mmol/kg, 179.96±2.45mg/g, 1.23±0.35%, respectively. And the color of the oil was red 1.6±0.1 and yellow 5.8. For the oil from Anhui using ultrasonic extraction, the acid value, peroxide value, saponification value, and unsaponification matter content were 47.60±1.35mg/g, 0.37±0.04mmol/kg, 188.73±1.76mg/g, and 1.70±0.34%, respectively. And the color of the oil was red 2.5±0.2 and yellow 5.8. While, for the oil from Jiangsu phoenix tree seed using soxhlet extraction method, the acid value, peroxide value, saponification value, unsaponification matter content were 3.73±0.02mg/g, 1.97±0.21mmol/kg, 183.74±2.37mg/g, and 0.90±0.05%, respectively. And the color of the oil was red 2.2±0.1 and yellow 5.8. For the oil from Anhui phoenix tree seed using soxhlet extraction method, the acid value, peroxide value, saponification value, unsaponification matter content were 51.43±0.11mg/g, 1.42±0.21mmol/kg, 195.11±2.46mg/g, 0.93±0.05%, respectively. And the colorof the oil was red 2.9±0.2 and yellow 5.8.(2)The qualitative and quantitative analysis of fatty acid of phoenix tree seed oil were performed by GC-MS. The composition of sn-2 fatty acid was also analyzed and the structure of triacylglycerols were also calculated according to the 1,3-random-2-random hypothesis. Results showed that the major fatty acids were palmitic acid(P, 17.43%), oleic acid(O, 22.23%), linoleic acid(L, 30.16%), and sterculic acid(S, 23.22%). Sterculic acid is a cyclopropene fatty acid. The major fatty acids in sn-2 of triacylglycerols were oleic acid(O, 30.62%) and linoleic acid(L, 48.26%). The major triacylglycerols of phoenix tree seed oil were PLS, LLS, OLS, PLL, PLO and POL.(3) The kinetics and thermodynamics of oil extraction from phoenix tree seed using n-hexane were studied. The Fick,s Law model was used to analyze the extraction process. Effective diffusion coefficients were from 5.18×10-13m2s-1 at 20℃to 1.29×10-12m2s-1 at 50℃. The Gibbs’ free energy(△G0) was from-2.57KJ/mol at 20℃ to-3.56 at 50℃,,and the Enthalpy(△H0) and Entropy(△S0) were 7.15 KJ/mol and 33.17 Jmol-1K-1, respectively.(4)The phoenix tree seed oil was hydrolyzed using Lipozyme TLIM to prepare fatty acids. Effect of reaction variables(reaction time,enzyme load,and reaction temperatures) on the hydrolysis were optimized using response surface methodology(RSM) as follows: reaction time 18.33 h, reaction temperature 44.86 ℃, enzyme load 10.37%(w/w, relative to the weight of total substrates), and substrate ratio of seed oil to water 1:10(w/v). Under these optimum conditions, the hydrolysis rate of oil in phoenix tree seed was 96.4±1.1%. The activation energy(Ea) of the hydrolysis were 39.25KJ/mol, respectively, based on Arrehenius law.(5)For enhancing the hydrolysis efficiency, The phoenix tree seed was directly used as substrate and In-situ method was used for the preparation of fatty acids. The reaction conditions were optimized as follows: reaction time 16.01 min, enzyme load5.59%(w/w, relative to the weight of seed), substrate ratio of seed to water 1:8.04(w/v), and reaction temperature 47.7℃. Under these optimum conditions, the hydrolysis rate was 98.3±0.8%, and the yield of fatty acids was 51.51±1.32%. The effect of variables on the hysrolysis of seed was in the order of enzyme load > reaction time > substrate ratio of seed to water > reaction temperature. |
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