| p-Coumaric acid and octacosanol are the main functional ingredients existing in sugar cane stalk. p-Coumaric acid crosslink with the cell wall polysaccharide or lignin, and octacosanol exists in the cuticle of the stalk. After production of sugarcane juice, the former deposits in the sugarcane bagasse, while the later are included both in sugarcane bagasse and the filter mud. Sugarcane bagasse and filter mud are the byproducts in sugar cane processing factories, which are mainly burnt or disposed as waste. The aim of this research is to extract p-coumaric acid and octacosanol from these byproducts. The main results were as follows:(1)A rapid determination method for p-coumaric acid and ferulic acid was established. A ratio spectra derivative spectrophotometry was developed for the simultaneous determination of p-coumaric acid and ferulic acid. In the solvents of ethanol or water or their mixtures with pH adjusted to 2.0, the UV spectra of the two phenolic acids were stable and showed the absorbance peak at 308nm for p-coumaric acid and at 320 nm for ferulic acid respectively. In the mixture of ferulic acid and coumaric acid, the recovery of this method was 93% to 103%; in the extracts of sugarcane bagasse alkaline hydrolysate, coumaric acid, the main phenolic acid, could be determined accurately. However, detection of ferulic acid (its content was much less than that of coumaric acid) is not satisfactory.(2)An improved technology for separation of p-coumaric acid from the alkaline hydrolysates from sugarcane bagasse was obtained.Firstly, activated charcoal was used to decolor the permeats of ultrafiltration of alkaline hydrolysates. FT-IR primarily proved that the brown substances in the alkaline hydrolysates were lignin or its monomers and activated charcoal was used to remove them. The results showed that addition of 3%(w/v) of activated charcoal decreased the color value by 78.1%, while only 14.36% of p-coumaric acid was lost. The decoloration technology significantly increased the purity of the final product,p-coumaric acid, and reduced the contamination of the resin by the brown substances, thus ensure the recycle of the resin.Secondly, the technology for adsorption of p-coumaric acid and reuse of the resin was established.717 and D201 anion exchange resin were compared for their adsorption and desorption of coumaric acid, the results proved that D201 was the better one. The optimal technology was:3 volume of resin was added into 100 volume of alkaline extracts and kept at room temperature for 50 min under constant stirring, the resin was recovered using 200-mesh nylon cloth,30 volume of eluents containing ethanol, HCl and water in a ratio of 60:4:36 was used to desorb p-coumaric acid from the resin..Thirdly, crystallization of p-coumaric acid was established. The solubility test of coumaric acid in aqueous ethanol solution proved that the concentration of ethanol should be kept at lower than 10%.In summary, after alkaline hydrolysis, decoloration by activated charcoal, adsorption by anion exchange resin, elution and crystallization, an average of 8255 mg of crystal coumaric acid from4 patches was obtained from one kilogram of sugarcane bagasse.(3) Preparation of octacosanol from sugarcane bagasse and filter mud.Extraction of octacosanol from sugarcane bagasse and filter mud by direct extraction using hot ethanol, ultrasonic treatment, reflux flow and supercritical fluid extraction (SFE) was compared and the results showed that extraction efficiency ranged in a decreasing order as follows: supercritical fluid extraction, reflux flow extraction, ultrasonic-aided extraction and hot ethanol extraction.5.687% of rough extract was obtained which contained 19.53% of octacosanol; after recrystallization using petroleum ether,1.614g product which contained 38.93% of octacosanol was obtained.
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