MICROENCAPSULATION OF FISH OIL BY Corresponding Author Hiep Nguyen Xuan Pharm.nxh@gmail.com MICROENCAPSULATION OF FISH OIL BY COMPLEX COACERVATION Hiep Nguyen Xuan*, Chien N. Nguyen ; Department of Industrial Pharmacy; Hanoi University of Pharmacy; 13-15 Le Thanh Tong Street, Hanoi city, Vietnam RESULTS INTRODUCTION Table 2: Effects of processing variables on the properties of fish oil microcapsules Fish oil which contains a lot of vitamin A, vitamin D, and omega-3 fatty acids, has been used popularly as a medicine or a food supplement. Fish oil, however, can be degraded easily by environmental factors. One of the methods that protect fish oil is microencapsulation. The aim of our study was to investigate the processing parameters on fish oil encapsulation. The core/ wall ratio Stirring speed ( rpm) Treatment Particle size (μm) Microcapsule yield (%) Encapsulation efficiency ( % ) 1:1 300 A X 87.82 59.42 400 B 82.37 60.73 500 C 50.41 ± 12 80.25 62.95 750 D 40.13 ± 10.2 81.94 64.11 1000 E 26.46 ± 9.1 79.33 63.27 1:2 C12 51.27 ± 11.4 82.09 65.32 C11 50.42 ± 12 2:1 C21 50.13 ± 9.2 72.20 61.89 MATERIALS Vitamin A palmitate (stabilized with tocopherol (E307), Roche, USA), gelatin (GE) ( type B, 250 bloom, 30 mesh ) and gum Arabic ( GA ) powder, fish oil, polyvinyl alcohol, 2-propanol, butylated hydroxytoluene (BHT), formaldehyde solution (37%–40% w/w), 10% v/v acetic acid solution, and 10% w/v sodium hydroxide solution (Sela Co, Ltd - Hanoi, Vietnam). METHODS Table 1: Formulations of fish oil microcapsules No. Ingredient 1 Gelatin 3.75 g 2 Gum arabic 3 Polyvinyl alcohol 0.50 g 4 Butylated hydroxytoluene (BHT) 0.04 g 5 Fish oil 2.10 g for the core/ wall ratio 1: 2 4.20 g for the core/ wall ratio 1: 1 8.40 g for the core/ wall ratio 2: 1 6 10 % v/v acetic acid solution To pH 4.5 7 10 % w/v sodium hydroxide solution To pH 9.7 8 20 % w/w formaldehyde solution 20 ml 9 Distilled water The effects of emulsification stirring speed (Fig 1) and the ratio of core to wall (Fig 2) on particle size, microcapsule yield and encapsulation efficiency Microcapsule yield (MY) At a constant ratio of core to wall (1: 1), MY got its maximum value at the stirring speed of 300 rpm, and its minimum value at the stirring speed of 1000 rpm. At a constant stirring speed of 500 rpm, the different ratio of core to wall showed significant difference in MY. Preparation of microcapsules The mixture of fish oil, polyvinyl alcohol and water was added into the solution of gelatin (12.5 %w/w) and gum arabic (12.5 %w/w) at 400C to make an oil in water emulsion. The emulsion was stirred at a range of 100-1000 rpm for 30 min and then adjusted to pH of 4.5-5 by adding 10 % acetic acid solution. The mixture was agitated at 250 rpm at 5–80C for 60 min and then changed to pH of 9.5–9.7 by using 10 % sodium hydroxide solution. Formaldehyde was added to the obtained mixture to form the cross–link gelatin with gum arabic. The mixture was stirred at 250 rpm for 22 h and then centrifuged at 4000 rpm for 15 min. The collected microcapsules were washed and dried. Chromatograms of standard (retinol palmitate) (Fig 3) and n – hexane extract of fish oil in microcapsules (Fig 4) (retention time: 4.322 min). Encapsulation efficiency (EE) EE increased with the homogenization rate and got its peak at the stirring speed of 750 rpm, but decreased at the stirring speed of 1000 rpm. The ratio of core to wall 1: 2 produced the best EE Microscopic photographs of fish – oil gelatin – acacia microcapsules using an optical microscope (x 100). The conditions for microencapsulation procedure were (A) 500 rpm, (B, C) 1000 rpm, (D) 300 rpm of stirring speed and 1 : 1 for the ratio of core to wall. Vacuum filter pH adjustment Centrifugation Determination of properties of microcapsules The average particle size was determined by using an 100X optical microscope and imaged using a Nikon camera. The vitamin A (retinol) content determined by HPLC was used to evaluate encapsulation efficiency. (HPLC Shimadzu system, Supelco Discovery, C8, 150 mm x 4.6 mm (5 μm) Column with a guard column 2 cm x 4.6 mm (5 μm) (Germany) was used with a mobile phase of 97: 3, methanol: water (v/v). The flow rate was 1 ml/ min. The wavelength of the UV detector was 325 nm) Encapsulation efficiency (EE) was calculated as percentage of the amount of retinol encapsulated in microcapsules compared to the total amount of retinol in fish oil material added. Microcapsule yield (MY) of the complex coacervation procedure in this study was determined by dividing weight of the coavervate prepared, by the initial weight of the materials used. Properties of microcapsules As the stirring speed increased, the particle size decreased At a constant stirring speed of 500 rpm, difference in the core to wall ratio had no significant change in particle size CONCLUSIONS The study showed the effects of the ratio of core to wall and emulsification stirring speed on encapsulation efficiency, microcapsule yield, particle size and morphology of microcapsules. The stirring speed was proved to be the most important parameter in fish oil microencapsulation among the studied parameters.