【作者】 罗艳玲；

【导师】 欧仕益；

【作者基本信息】 暨南大学 ， 食品科学， 2006， 硕士

【摘要】 本论文探讨了采用NaOH碱解玉米皮和蔗渣制备酚酸的工艺，主要结果如下： 碱解玉米皮释放结合于多糖上的阿魏酸的最佳工艺为：采用含1％NaOH的50％乙醇溶液在85℃下回流反应2h提取玉米皮（1：10，W／V）中阿魏酸，溶液添加50mg／100ml的亚硫酸氢钠以防止阿魏酸氧化。碱解液中阿魏酸的纯化工艺为：将碱解液减压浓缩，用盐酸将pH调节至3.0，每次用2倍体积的乙酸乙酯萃取三次，取酯相，减压挥干乙酸乙酯，用碱液溶解，再用盐酸调至pH=2，获得产品为黄色油状物；检测表明，阿魏酸纯度82.69％，收率为148.92mg／10g玉米皮。实验还探讨了利用活性炭吸附分离阿魏酸的工艺。结果表明，粉末活性炭对阿魏酸的吸附能力很强，最大吸附量为325～340mg／g，在低浓度下（≤5mg／100ml）能将溶液中的阿魏酸全部吸附，pH在2.0～9.0范围内，粉末活性炭对阿魏酸的吸附不受pH的影响。乙醇、乙酸乙酯只能将活性炭所吸附的少部分阿魏酸洗脱出来，而2.0％的NaOH溶液能完全洗脱被吸附的阿魏酸。薄层层析结果表明，采用粉末活性炭从玉米皮碱解液中分离的阿魏酸纯度很高。 碱解蔗渣释放、纯化酚酸的最佳工艺为：1％NaOH在30℃下碱解蔗渣4h，并采用阴离子交换树脂和大孔吸附树脂分两步纯化样品，得到精制品主要成分的纯度为93.57％。阴离子交换工艺为：料液pH为9.0，室温条件下以流速1mL／min上柱，水洗至无色后，加洗脱剂洗脱，洗脱剂配比为V_HCl：V_无水乙醇：V_H2O=4：60：36，洗脱速度为1mL／min。大孔吸附树脂纯化工艺为：采用NKA-9树脂对样液静态吸附1h，吸附pH为5，再将大孔吸附树脂装柱，用30％乙醇洗脱，洗脱流速为1mL／min。 采用HPLC制备色谱获得精制样品的主成分，通过HPLC、HPLC／MS、红外光谱和紫外光谱鉴定，得出精制品中的主要成分为对香豆酸。 实验对碱解产物的功能性进行了初步研究。结果表明在离体环境下，蔗渣碱解产物可有效清除羟基自由基、超氧阴离子自由基以及DPPH，其对油脂的抗氧化活性和同浓度的阿魏酸溶液相当。更多还原

【Abstract】 Sodium hydroxide was used to release phenolic acids from maize bran and sugarcane bagasse respectively.For releasing ferulic acid from maize bran, de-starched and deproteined maize bran was suspended in ten volume of 50% of ethanol solution (v/w) containing 1% NaOH and reacted at 85℃ for 2h; and 50mg /100ml of sodium sulfite was added to the extraction solution to prevent oxidation of released ferulic acid. The extracts were concentrated, pH adjusted to 3.0 and extracted three times with two volume of ethyl acetate. HPLC analysis showed that the purity of ferulic acid is 82.69%; the yield of ferulic acid is 148.92mg/10g maize bran. Active charcoal was also investigated to separate ferulic acid in the solution. The results showed that powdered active charcoal had high capacity for adsorbing ferulic acid. Its maximum adsorption capacity was 325~340mg/g and its lowest adsorbing concentration for ferulic acid was less than 5mg/100ml under pH 2.0～9.0. 2.0% of NaOH desorbed almost 100% of adsorbed ferulic acid, however, alcohol and ethyl acetate desorbed less than 30% of the adsorbed ferulic acid. The result of TLC showed that ferulic acid separated by active charcoal from alkali-hydrolyzed products had high purity.Phenolic acids could be fully released from sugarcane bagasse by suspending sugarcane bagasse in ten volume of 1% NaOH(w/v) and reacted at 30℃ for 4h under constant stirring. The phenolic acids in alkaline extracts were purified by NKA-9 macroporous resin after anion chromatography using 717-anion resin. The adsorption condition for anion chromatography was pH 9.0 and the flow rate kept at 1 mL/min; the phenolic acids were desorbed with ethanol:water: HCl 60:36:4 (v:v:v) at elution rate 1mL/min. The eluents were vacuum-evaporated and the crystals were dissolved in deionized water (pH= 5.0) and adsorbed by NKA-9 macroporous resin in a flask for 1h. The mixture was loaded onto a column and desorbed using 30% ethanol at 1 mL/min. After purification, the purity of products reached 93.57%.Preparative liquid chromatography was used to separate the main component of alkali-released products, and HPLC, HPLC/MS, IR and UV analysis showed that the main component was p-coumaric acid rather than ferulic acid in sugarcane bagasse.The antioxidant activity of alkali-released products from sugarcane bagasse for their protection against peroxidation of linoleic acid was also investigated. The results showed that the product had equivalent antioxidant activity to ferulic acid at the same concentration. Moreover, the alkali-released products could effectively scavenge free更多还原