Phytosterols are important bioactive compounds which have several health benefits including reduction of serum cholesterol and preventing cardiovascular diseases. The most widely used method in the synthesis of its ester analogous form is the use of catalysts and solvents. These methods have been found to present some safety and health concern. In this paper, an alternative method of synthesizing phytosterol ester from soybean sterol and acetic anhydride was investigated. Process parameters such as mole ratio, temperature and time were optimized. The structure and physicochemical properties of phytosterol acetic ester were analyzed. By the use of gas chromatography, the mole ratio of soybean sterol and acetic anhydride needed for optimum esterification rate of 99.4% was 1:1 at 135 °C for 1.5 h. FTIR spectra confirmed the formation of phytosterol ester with strong absorption peaks at 1732 and 1250 cm(-1) , which corresponds to the stretching vibration of C=O and C-O-C, respectively. These peaks could be attributed to the formation of ester links which resulted from the reaction between the hydroxyl group of soybean sterol and the carbonyl group of acetic anhydride. This paper provides a better alternative to the synthesis of phytosterol ester without catalyst and solvent residues, which may have potential application in the food, health-care food, and pharmaceutical industries.

Phytosterols are bioactive components capable of reducing cholesterol level in serum and reducing risk of arteriosclerosis. In this study, conditions for the synthesis of maximum yield of phytosterol linoleic ester (PLE) was optimized and the physicochemical properties and in vitro bioaccessibility of the PLE was assessed. Under the optimized condition of 1:1.1 mole ratio of phytosterol and linoleoyl chloride at 80 o C for 1.5h, the conversion rate of phytosterol reached 96.1%. Its solubility in oil increased 20 times, up to 33.8%. Also, peroxide value of PLE was much lower than linoleic acid (32.9 and 47.0 mmol/kg), which means better oxidative stability. Bioaccessibility of PLE was affected by time, concentration of bile extract, and dissolved medium. It was 4.93% alone, increased by 2.5times compare to phytosterol; or 53.46% in oil, under the condition of 40mg/mL bile extract for 120min. In conclusion, under the tested condition, phytosterol conversion rate, its solubility in oil and bioaccessibility were improved significantly. The method showed great potential in manufacture high quality and quantity of PLE.

No abstract

No abstract

No abstract

Phytosterols are bioactive components capable of reducing the level of cholesterol in serum. In this study, phytosterol acetic ester (PA), phytosterol oleate ester (PO) and phytosterol linoleic ester (PL) were synthesized from phytosterol (PS) and organic acid to improve the solubility of phytosterols in oil. The purities of PA, PO and PL were 98.4, 95.9 and 95.7%, respectively. Caco-2 cell monolayers and Wistar rats were used to research the bioavailability of synthesized esters (PE) in vitro and in vivo. Experiments using the Caco-2 cell monolayer model showed that the transport mechanism of phytosterol esters was passive transport. Experiments in vivo showed that the PS content in rat blood reached the highest level at 3 h, with a value of 21.82 μg/mL. PS content in the liver was the highest at 3 h, with a value of 43.65 μg/g. Bioavailability of PL is the highest, reaching a value as high as 19.57%. Acute study in the rats showed that the PS concentration in blood was at the safe level, and it had no side effects for health. In conclusion, the bioavailability of PL and PO is better than PS, PL and PO have more advantages in application.

This paper presents a method for extracting rice bran oil using magnetic immobilized cellulase (MIC) in a magnetic fluidized bed (MFB). Cellulase was immobilized on Fe3O4/SiO x -g-P (glycydylmethacrylate) with an average grain size of 120 nm. The rice bran was hydrolyzed using MIC combined with magnetic immobilized alkaline protease to extract rice bran oil. Under intermittent conditions, the MIC concentration was 1.6 mg/g, the liquid to material ratio was 4:1, the enzymatic hydrolysis time was 150 min, and the oil yield was as high as 85.6 ± 1.20% at 55 °C. The fluid in the MFB had a magnetic field strength of 0.022 T, a flow velocity of 0.005 m/s, and an oil extraction rate of 90.3%. This provides a theoretical basis for the extraction of rice bran oil using the subsequent MFB hydroenzyme method.

No abstract