| Monoacylglycerols (MAGs) are extensively used as emusifiers in food, pharmaceutical, cosmetic and many other fields. Glycerol monooleate (GMO), a MAG which has distinct properties, is used as antifoaming agent in juice processing and as a lipophilic emulsifier for water-in-oil applicatins. It also serves as a moisturizer and flavoring agent. Wild applications of various forms of GMO were found in cosmetics ang as a common excipient in antibiotics and other drugs. The objective of this study was to assess the opportunity for producing GMO by glycerolysis of high oleic sunflower oil (HOSFO) in organic solvents. The main topics of this paper were just as follow:(1) The synthesis of GMO by glycerolysis of high oleic sunflower oil in a pure solvent had been studied. In tert-butanol, Novozym 435 was selected to catalyze the reaction. The optimum condition for GMO production was found to be the mole ratio of HOSFO to glycerol 1:3, the amount of NOVO 435 3% (w/w) of oil, water content in glycerol 5% (w/w) and 40% (w/v) of HOSFO in tert-butanol. The temperature was controlled at 50℃. Under these conditions, the yield of 71.35% MAG was obtained at 8 h. Then a packed-bed reactor (PBR) system was employed in continuous production, the yield of 63% MAG was obtained at a flow rate of 0.2 ml/min. The long-term operation of the PBR showed that the system was stable.(2) The binary solvent mixtures had been studied to overcome the weakness of tert-butanol. A binary mixture of TB/TP (80/20 v/v), whose melting and boiling points were 6.9℃, 85℃respectively, was found to be efficient in producing MAG. The optimum condition for GMO production was found to be the mole ratio of HOSFO to glycerol 1:3, the amount of NOVO 435 3% (w/w) of oil, water content in glycerol 3% (w/w) and 30% (w/v) of HOSFO in tert-butanol. The temperature was controlled at 50℃. Under these conditions, the yield of 71.35% MAG was obtained at 8 h. The NOVO 435 was stable.(3) Molecular distillation (MD) was used to purity GMO synthesized by lipase-catalyzed reaction. The technique was made up of two stages: first glycerol and fatty acid were distilled with operating pressure at 0-5Pa, condensation temperature at 40℃, feed temperature at 100 ℃, preheat temperature at 80℃, rotational speed 200 r/min, evaporator temperature at 140℃; then GMO was distilled with evaporator temperature at 180℃. High-purity GMO (93.3%) was achieved, and the recovery of GMO was 81.45%.(4) A pilot-plant test was conducted. 20 kg HOSFO, 6 kg glycerol and 60L binary mixture of TB/TP (80/20 v/v) were added into the reactor. 100g enzyme was installed in a column, whose temperature was controlled at 50℃. The flow rate was 1L/min, to control the pre-column pressure at 0.2Mpa. The yield of 68.17% MAG was obtained after 12h.(5) Physical and chemical analysis of products indicated that, the GMO products contained MAG 93.4%, free glycerin 0.6%, acid value 0.4, hydroxyl value 321, iodine value 77, lead 0.08mg/kg, arsenic 0.06mg/kg, residue on ignition 0.03%, saponification value 174, which met the requirements of FCC-V very well. It melt at 35℃, and was more convenient. The storage test showed that the most effective antioxidants were TBHQ200 mg/kg; VE 500 mg/kg; Citric acid 250 mg/kg.
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