Influence of Wall Material and Inlet Drying Air Temperature on the Microencapsulation of Fish Oil by Spray Drying

Transcription

1 Food Bioprocess Technol (2013) 6: DOI /s ORIGINAL PAPER Influence of Wall Material and Inlet Drying Air Temperature on the Microencapsulation of Fish Oil by Spray Drying Mortaza Aghbashlo & Hossien Mobli & Ashkan Madadlou & Shahin Rafiee Received: 12 November 2011 / Accepted: 25 January 2012 / Published online: 10 February 2012 # Springer Science+Business Media, LLC 2012 Abstract Several single and composite milk-originated wall materials were used to microencapsulate fish oil via spray drying at various inlet drying air temperatures. Skim milk powder (SMP), whey protein concentrate, whey protein isolate (WPI), 80% WPI+20% milk protein concentrate, and 80% WPI+20% sodium caseinate (NaCas) were applied as the wall for capsules generated at drying air temperatures of 140, 160, and 180 C. The higher the drying air temperature, the higher was the particle size, encapsulation efficiency, and peroxide value and the lower was the moisture content and bulk density. The microcapsules prepared with SMP showed the highest encapsulation efficiency and lowest peroxide value for the oil due to the presence of lactose in its chemical composition. Differential scanning calorimetry and Fourier transform infrared analyses indicated the absence of any significant interaction between SMP and fish oil. Keywords Fish oil microencapsulation. Spray drying. Wall material. Encapsulation efficiency. Lipid oxidation M. Aghbashlo (*) : H. Mobli : S. Rafiee Faculty of Agricultural Engineering and Technology, University of Tehran, Karaj, Iran mortazaaghbashlo@yahoo.com A. Madadlou Department of Food Technology, Institute of Chemical Technologies, Iranian Research Organization for Science & Technology (IROST), Tehran, Iran Introduction Fish oil contains a high amount of n-3 polyunsaturated fatty acids (PUFAs) which have documented beneficial effects on human health (Drusch et al. 2007). A successful incorporation of n-3 PUFAs in processed foods is, however, limited due to their low solubility in most food systems and excessive susceptibility to oxidation. Microencapsulation is a technique by which solids, liquids, or even gases may be enclosed in miniature sealed capsules that can release their contents at controlled rates under specific conditions (Klaypradit and Huang 2008; Fang and Bhandari 2010). The main reasons of encapsulation is to isolate the core material from the deteriorating effects of oxygen, retard the evaporation of a volatile core, control the rate at which it leaves the microcapsule, improve the handling properties of a sticky material, mask the taste or odor of the core, isolate a reactive core from chemical attack, and, finally, todilutethecorematerialwhenitshouldbeusedinonlyvery small amounts (Shahidi and Han 1993; Gharsallaoui et al. 2007). Amongst many techniques, such as spray drying, spray cooling/chilling, extrusion, fluidized bed coating, coacervation, liposome entrapment, etc. (Desai and Park 2005; Fang and Bhandari 2010), spray drying is the most commonly used method to encapsulate food ingredients in a few seconds due to its low cost and the availability of equipment (Gharsallaoui et al. 2007). Since lipids are oxidation-sensitive compounds, it is vital to protect them from oxidation reactions during drying. The quality of spray-dried microcapsule is quite dependent on the spray dryer operating parameters and properties and the composition of the feed emulsion. Recently, several studies have been undertaken to encapsulate fish oil via spray drying using different wall materials. The oxidative stability of fish oil encapsulated by skim milk powder (SMP), sodium caseinate (NaCas), and lactose at a drying air temperature of 177 C (Keogh et al. 2001); coated by whey protein isolate (WPI),

2 1562 Food Bioprocess Technol (2013) 6: NaCas, and dextrins at a drying air temperature of 150 C (Kagami et al. 2003); microencapsulated within modified cellulose at a drying air temperature of 160 C (Kolanowski et al. 2006); surrounded by n-octenylsuccinate-derivatized starch at an air temperature of 180 C (Drusch et al. 2006a) or by an amorphous matrix containing trehalose at an inlet drying air temperature of 170 C (Drusch et al. 2006b); microencapsulated at a drying air temperature of 180 C using different types of wall materials (Drusch et al. 2007) and at a drying air temperature of 180 C stabilized by blends of chitosan, modified starch, and glucose (Shen et al. 2010) was investigated. In spite of the enormous amount of research carried out, literature survey showed that less effort was made to study the combined effect of inlet drying air temperature and wall material on the quality of fish oil microencapsulated by spray drying. The main objective of this contribution was therefore to encapsulate fish oil using various single and composite milk-originated wall materials under different drying temperatures and select the best drying air temperature and wall material based on the quality of generated microcapsules. Materials and Methods Materials Fish oil was obtained from Qeshm Fish Oil Co. (QFOC, Qeshm, Iran). Table 1 shows the fatty acid composition of the oil. Whey protein concentrate (WPC) and WPI were kindly provided by Alra Foods (Viby, Denmark). Milk protein concentrate (MPC), NaCas, and SMP were purchased from Sundiet SA (Corminboeuf, Switzerland), Iran Caseinate Co. (Tehran, Iran), and Pegah Dairy Co. (Tehran, Iran), respectively. Phosphate buffer, sodium azide, sodium Table 1 Fatty acid composition of the fish oil Common name Shorthand Percentage Myristic acid 14: Palmitic acid 16: Palmitoleic acid 16: Stearic acid 18: Oleic acid 18: Linoleic acid 18:2 (n-6) 1.80 α-linolenic acid 18:3 (n-3) 3.20 Gamma-linolenic acid 18:3 (n-6) 0.11 Arachidic acid 20: Eicosapentaenoic acid 20:5 (n-3) 13.2 Docosadienoic acid 22:2 (n-6) 0.36 Docosahexaenoic acid 22:6 (n-3) 12.2 Others Total 100 citrate, sodium salicylate, acid acetic glacial, and chloroform were purchased from Merck (Darmstadt, Germany). Potassium iodide and 1-butanol were provided by Acros Organics and Applichem, respectively. Hexane and starch were provided by Scharlau Chemie S.A. (Sentmenat, Spain). Preparation of Emulsions Milk-originated wall material solution was prepared by dissolving 20 g powder in 70 g phosphate buffer (5 mm, ph 7.0) and stirring at 500 rpm for 30 min at room temperature; sodium azide (100 mg/l) was added to the solution as an antimicrobial agent. The wall material solution was stored at 4 C for 10 h to allow complete hydration (Madadlou et al. 2009). Ten grams of fish oil was progressively added to the wall material solution while stirring at 3,500 rpm for 2 min using a rotor-stator blender (Ultra-turrax IKA T18 Basic, Wilmington, USA), after which the emulsion was homogenized at 24,000 rpm for 5 min and used as the feed liquid of spray drying. Five single and composite wall materials including WPC, WPI, SMP, 80% WPI+20% MPC, and 80% WPI+20% NaCas were used in the preparation of aqueous solutions. The chemical composition of emulsions is represented in Table 2, in accordance with the reports of the manufacturers of wall materials. Microencapsulation by Spray Drying Spray drying of the feed liquid was done in a Büchi Mini Spray B-191 (Flawil, Switzerland) equipped with a twofluid nozzle atomizer (diameter, 7 mm). The operational conditions of the spray drying were as follows: inlet drying air temperatures, 140, 160, and 180 C; peristaltic pump rate, 10%; aspirator rate, 65%; and spraying air flow rate, 700 L/h. Before each experiment, the dryer was run with distilled water for 15 min in order to achieve desirable steady-state conditions. The finished microcapsules into the product vessel were stored in a sealed plastic bag for further analysis. Sample preparation was replicated twice. Table 2 Composition of emulsion obtained from different wall materials Wall material Water Protein Fat Carbohydrate Fiber Ash WPC WPI SMP % WPI+20% MPC 80% WPI+20% NaCas

3 Food Bioprocess Technol (2013) 6: Microcapsule Analysis Moisture Content, Particle Size, and Bulk Density Determination For moisture content determination, 2 g of microcapsule was dried in an oven (Memmert, Germany) at 70 C for 24 h (AOAC 1984). The samples were weighted using AAA 250 L balance (Adam, Co., UK) with precision of ± g. The particle size of the microcapsules was measured using a laser diffraction-based particle counter (PC-2000, Spectrex, Co. USA. For this purpose, 0.3 g of the microcapsule was suspended in ethanol under agitation and the particles size was recorded. The bulk density of the microcapsule was determined by transferring 2 g microcapsule into a 10-mL graduated cylinder. Packed bulk density was determined from the volume of the microparticle in the cylinder after being tapped by hand on a bench 50 times (Goula et al. 2004). Encapsulation Efficiency Surface oil was determined by mixing 15 ml hexane with 2 g dried microcapsule and shaking the mixture for 2 min at room temperature. The slurry was then filtered through a Whatman no. 1 filter paper; each filter paper with collected microparticles was rinsed three times with 20 ml hexane (Tonon et al. 2011). The filtrate solution containing the extracted oil was transferred to an oven at 70 C for 6 h for the complete evaporation of hexane. The surface oil of the microcapsule was computed by recording the initial and final weights of the solution container, and then the encapsulation efficiency was calculated as follows: Total oil Surface oil EE ¼ 100 ð1þ Total oil Peroxide Value A de-emulsification reagent followed by heating and centrifugation was applied to release the fish oil from the microcapsules (Ahn et al. 2008). It was prepared by dissolving 10 g sodium salicylate and 10 g sodium citrate separately in reverse osmosis (RO) water, mixing together with 18 ml 1- butanol, and then making up to 90 ml with RO water. Ten grams of the microcapsule was mixed with 20 ml water at 50 C in a 250-mL Erlenmeyer flask with a stopper. Fifteen microliters of the de-emulsification reagent was added to this mixture and magnetically stirred at 70 C for 10 min. The resulting mixture was centrifuged at 5,000 g for 10 min and the extracted oil used for the peroxide value test. The peroxide value of the encapsulated fish oil was determined according to AOCS method (AOCS Official Method 1993). For this purpose, 1 g of extracted fish oil was taken and transferred to a 125-mL Erlenmeyer flask with a stopper, followed by adding 6 ml of 3:2 acid acetic/ chloroform solution to the sample and then swirling the sample container to dissolve the oil. Then, 0.1 ml potassium iodide was added to the oil solution and the Erlenmeyer flask occasionally shaken for exactly 1 min. After this, 10 ml RO water and 0.1 ml starch solution were added to the solution, respectively. Finally, the solution was gradually titrated under constant agitation with N sodium thiosulfate until the gray color of the solution almost disappeared. The peroxide value (milliequivalents peroxide/1,000 g sample) was computed using the following equation: ð POV ¼ S B ÞN 1000 ð2þ W where B is the titration of blank (in milliliters), S is the titration of the sample (in milliliters), N is the normality of the sodium thiosulfate solution, and W is the weight of sample (in grams). Storage Stability Test Microcapsules prepared with SMP as the wall material at an inlet drying air temperature of 180 C (see Discussion ) were stored under environment condition at ~25 C. The peroxide value and the residual encapsulated oil of the stored microcapsule were determined during 4 weeks storage. Differential Scanning Calorimetry (DSC) Differential scanning calorimetry (DSC) thermograms of the SMP-coated microcapsule at a drying temperature of 180 C were obtained by a differential scanning calorimeter (DSC Pyris 6, Perkin Elmer Co., Norwalk, CT, USA) at a heating rate of 10 C/min from 30 to 200 C under oxygen injection as a purge gas with a flow rate of 20 ml/min with a sample weight of 3 mg. Fourier Transform Infrared (FTIR) Spectroscopy The Fourier transform infrared (FTIR) spectra of fish oil, SMP-, and SMP-coated microcapsules at a drying air temperature of 180 C were obtained on a Perkin Elmer 2000 FTIR system (Perkin Elmer) using the KBr disk method. The scanning range was 450 4,000 cm 1. Scanning Electron Microscopy (SEM) The SMP microcapsule prepared at an inlet drying air temperature of 180 C was sprinkled onto a two-sided adhesive tape and sputter-coated with gold. Then, the morphological

4 1564 Food Bioprocess Technol (2013) 6: features of the capsule were observed by SEM (VEGA, TESCAN Co., Czech Republic) with an accelerated voltage of 15 kv. Statistical Analysis One-way analysis of variance was performed using SPSS (ver. 15) software to evaluate the effect of drying temperatures and wall materials on the parameters studied. Differences among mean values were examined using the LSD and Duncan test at the p<0.05 significance level. Results and Discussion Moisture, Size, and Density of Capsules The characteristics of the generated microcapsules are reported in Table 3. The moisture content of the capsules varied from a minimum value of 1.41% to a maximum value of 4.36% (Aghbashlo et al. 2012). Increasing the inlet drying air temperature accelerated the moisture evaporation rate, resulting in a lower moisture content for the finished microcapsule (p<0.05). Similar findings have been reported by Goula et al. (2004) in the spray drying of tomato pulp, by Chegini and Ghobadian (2005) for orange juice powder, and by Quek et al. (2007) for spray-dried watermelon. SMP-coated microcapsules had the highest moisture content (p<0.05), due probably to the presence of lactose in the chemical composition of SMP. Lactose may form a continuous glass phase at droplet surface in which protein chains are dispersed, resulting in the formation of a tough leather-like skin, leading to virtual halt of drying. Case hardening entrapped the moisture inside the particle, and therefore capsules with higher moisture content were produced. SMP-coated capsules were also larger than those with other treatments (Tale 3), followed by those with WPI, WPC, 80% WPI+20% MPC, and 80% WPI+20% NaCas. A similar observation for the effect of lactose on formation was reported by Rosenberg and Sheu (1996) during the microencapsulation of volatiles in whey protein-based wall systems. Moreover, according to Moreau and Rosenberg (1996), the lactose glass phase increases the hydrophilic nature of the wall matrix and limits the diffusion of the solvent through the wall. The particle size of capsules varied from a minimum value of 1.37 μm to a maximum value of 4.59 μm(aghbashloetal. 2012). Increasing the inlet drying air temperature increased (p<0.05) the particle size of microcapsules (Table 3). Higher drying air temperature speeds up the drying rate and therefore accelerates the migration of crust-forming soluble materials to the surface of the atomized droplets. The rapid formation of a dried crust layer on the surface of the droplets hindered the shrinkage of microparticles, and therefore larger capsules were produced (Chegini and Ghobadian 2005; Reineccius 2004). A similar trend was reported by Tonon et al. (2011) while studying the effect of emulsion composition and inlet air temperature on the microencapsulation of flaxseed oil by spray drying. Table 3 Characteristics of the generated microcapsules using different wall materials at different drying air temperatures Wall material Inlet drying temperatures ( C) Moisture content Particle size (μm) Bulk density (kg/m 3 ) Encapsulation efficiency Peroxide value (meq/kg) WPC ±0.02 a 2.62±0.007 a ±3.96 ab 49.60±1.29 a 9.90±0.20 a ±0.05 bc 2.39±0.014 b ±2.07 abc 44.22±0.88 b 8.50±0.10 b ±0.14 d 2.26±0.029 c ±4.59 d 40.59±1.28 c 7.50±0.10 c WPI ±0.04 a 3.10±0.004 e ±1.95 a 75.65±1.19 d 6.95±0.05 d ±0.05 bc 2.76±0.014 f ±2.19 cd 70.27±0.97 ef 6.65±0.05 de ±0.00 cd 2.38±0.005 b ±2.26 d 68.36±0.66 eh 6.40±0.10 eg SMP ±0.07 bc 4.59±0.017 g ±1.54 f 81.94±0.24 g 6.15±0.05 gh ±0.02 d 3.78±0.010 h ±1.70 g 74.22±0.60 di 6.00±0.10 h ±0.17 e 3.09±0.004 e ±1.95 a 71.26±0.34 f 5.55±0.15 i 80% WPI+20% NaCas ±0.12 a 1.53±0.012 i ±2.64 h 72.19±0.36 fi 7.45±0.05 c ±0.10 bf 1.41±0.010 j ±3.02 i 68.44±0.75 eh 6.85±0.05 de ±0.14 d 1.37±0.007 j ±3.49 j 65.33±0.14 j 6.35±0.15 gh 80% WPI+20% MPC ±0.22 af 2.41±0.011 b ±4.20 bc 75.72±1.20 d 7.35±0.15 c ±0.49 bc 2.04±0.024 k ±2.26 d 70.51±0.89 ef 6.85±0.15 d ±0.03 e 1.68± ±4.88 k 66.28±0.67 hj 6.35±0.15 egh Different letters in the same column indicate significant differences (p<0.05)

5 Food Bioprocess Technol (2013) 6: As the inlet drying air temperature increased, the bulk density of the capsules decreased (Table 3), most probably because larger capsules were obtained at higher air temperatures. According to Goula et al. (2004), the higher drying air temperatures associated with lower bulk densities because particle size increased with increasing drying air temperatures. Tonon et al. (2011) also verified that the higher drying rate obtained at a higher drying temperature probably produces larger volume spray-dried capsules, resulting in a lower bulk density. The SMP-coated microcapsule had the lowest (p<0.05) bulk density, possibly due to the large particle size. The highest bulk density belonged to the composite WPI and NaCas microcapsules because of the smaller particle sizes obtained using this type of wall material. Encapsulation Efficiency The encapsulation efficiency varied from 40.59% to 81.94% and was significantly influenced (p<0.05) by the drying air temperature. As the drying air temperature increased, the efficiency of fish oil encapsulation increased (Table 3). Higher drying air temperatures accelerated the drying rate of droplets, promoting the fast formation of particle crust. The crust, as soon as formed, provided a firm membrane around the particles, preventing further leaching of oil from the droplet. The same behavior was observed by Bhandari et al. (1992) in the encapsulation of citral and linalyl acetate by spray drying. Liu et al. (2000) also verified the positive effect of higher drying air temperature for retention of flavor during spray drying. SMP-surrounded capsules had the highest encapsulation efficiency (p<0.05), followed by those coated with 80% WPI+20% MPC, WPI, 80% WPI+20% NaCas, and WPC. It is argued that the presence of disaccharide lactose in the chemical composition of SMP could alter the properties of the wall, therefore facilitating crust formation and reducing the diffusion of the entrapped oil to the surface of the particles. Development of nitrogenous polymers and melanoidins as a result of the reaction between the amino groups of proteins and the carbonyl group of lactose (Millard reaction) might also have a significant contribution in the formation of the tough skin. Protein carbohydrate conjugates formed by the Maillard reaction have a good potential for the stabilization of fish oil microcapsules (Augustin et al. 2006) by changing the physical properties of the wall. On the other hand, according to Gharsallaoui et al. (2007), lactose in its amorphous state acted as a hydrophilic sealant that significantly limited the diffusion of the hydrophobic core through the wall, thus leading to high microencapsulation efficiency values. It was expected that treatment prepared with 80% WPI+20% NaCas, which had the smallest particle size, would have the lowest encapsulation efficiency due to the postponed crust formation. In contrast, this treatment provided a relatively high efficiency. This can be explained by the higher emulsion viscosity observed visually for this treatment, which rebated the oil diffusion inside the sprayed droplets and made the oil penetration to the particle surface difficult, therefore raising the encapsulation efficiency. Peroxide Value The peroxide value of pure fish oil was 5.00±0.20 meq/kg and increased during spray drying with increasing drying air temperature (Table 3). The higher the process temperature, the higher was the amount of generated peroxides, owing to the rapid oxidation of lipids which occurred due to the intensive energy provided at higher drying temperatures. Serfert et al. (2009) found that the hydroperoxide content of microencapsulated fish oil at inlet/outlet temperatures of 210/90 C was three times higher than that produced at 160/ 70 C. Tonon et al. (2011) also verified that the use of a higher inlet drying air temperature increased the peroxide value. Microcapsules prepared with SMP possessed the lower peroxide value for all drying air temperatures (Table 3). It is argued that the early formation of particle crust and the higher encapsulation efficiency for this treatment could most probably shield the oil from oxidation attacks. The lower the encapsulation efficiency, the higher was the amount of lipid at the surface of the particle subjected to oxidation due to the direct contact with the oxygen of drying air. Tonon et al. (2011) reported the lowest peroxide value of meq peroxide per kilogram oil for the highest encapsulation efficiency when investigating the effect of emulsion composition and inlet drying air temperature on the microencapsulation characteristics of flaxseed oil. Young et al. Fig. 1 Effect of storage time on the peroxide value and residual encapsulated oil of fish oil microencapsulated within SMP at a drying air temperature of 180 C

6 1566 Food Bioprocess Technol (2013) 6: (1993) have found that the peroxide value of crude fish oil was between 3 and 20 meq/kg. The values obtained for the produced microparticles in this research were well below the acceptable limit of 20 meq/kg oil. Fig. 2 DSC scans of fish oil, SMP, and fish oil microcapsules, respectively

7 Food Bioprocess Technol (2013) 6: Fig. 3 FTIR spectra of pure fish oil, SMP, and fish oil microcapsules, respectively Storage Stability Test SMP-coated fish oil capsules produced at a drying air temperature of 180 C were selected as having the best treatment according to the encapsulation efficiency and the peroxide value. Capsules were stored for 4 weeks at room temperature and their peroxide value and residual encapsulated oil (the amount of oil retained within the capsules) were monitored, as shown in Fig. 1. The residual encapsulated oil decreased from 82.00% to 59.35%, and the peroxide value of the encapsulated oil increased from 6.4 to 8.35 meq/kg oil. The longer the storage time, the lower was the amount of retained oil inside the capsules and the higher was the peroxide value. Oil could be released to the surface of the microcapsule during storage, leading to a poorer oil protection against oxidation. It could be related to the physical and chemical change of the capsule wall and the molecular diffusion of oil. The released oil, when in contact with oxygen, is much more susceptible to oxidation than its encapsulated form. On the other hand, by progressing the storage time, the amount of permeated oxygen from the wall to the inside of the particle dramatically increased, and therefore the peroxide formation prompted, accordingly. DSC Analysis DSC scans of pure fish oil, SMP, and fish oil microcapsule produced at an inlet drying air temperature of 180 C are shown in Fig. 2. The DSC analysis of pure fish oil showed a Fig. 4 SEM image of the SMP-coated fish oil produced by spray drying at a drying air temperature of 180 C.

8 1568 Food Bioprocess Technol (2013) 6: characteristic, sharp endothermic peak at 1 C corresponding to its glass transition temperature. The initial (T gi ), mid (T gp ), and final (T ge ) structural glass transition temperatures of fish oil were 17, 8, and 1 C, respectively. The DSC analysis of pure SMP showed a sharp endothermic peak at 52 C corresponding to its glass transition temperature. The T gi, T gp,andt ge of SMP were 47, 49, and 52 C,respectively. The DSC analysis of fish oil microcapsule indicated two sharp and weak endothermic peaks at 0 and 55 C corresponding to the glass transition temperature of fish oil and SMP, respectively. At the first and second endothermic peaks, the T gi, T gp, and T ge were 15, 7, and 0 C and 45, 49, and 55 C, respectively. The DSC analysis revealed a negligible change in the glass transition temperature of fish oil, indicating no modification or interaction between the fish oil and SMP in the structure of fish oil microcapsule. FTIR Analysis As shown in Fig. 3, the virtual mixture of pure SMP and fish oil exhibited almost the same FTIR spectrum compared with fish oil microcapsule, which demonstrates that there was no chemical interaction between oil and SMP in the structure of the microcapsule. The FTIR spectral study confirmed that the good encapsulating characteristic of SMP completely related to the physical properties of its compositions. SEM Image Figure 4 shows the SEM image of the SMP-coated microcapsule generated at an inlet drying air temperature of 180 C. The SEM image shows well-separated microparticles with a spherical shape and smooth surface. Also, it is obvious from this figure that the fresh microcapsule is like a smooth ball and has no cracks and pores, which is vital in preventing the oil from oxidation reactions and the undesired release of oil droplets to the surface of the particles. Conclusion Spray drying is a suitable method to encapsulate fish oil within milk-originated wall materials without significant deterioration of oil quality. Increasing the inlet drying air temperature increased the encapsulation efficiency, peroxide value, and particle size, but decreased the residual moisture content and bulk density. SMP would provide an inexpensive, easily accessible and highly efficient wall for the capsules owing to its chemical composition. The presence of disaccharide lactose in the composition of SMP improves the encapsulating capability, suggesting the addition of lactose or other (reducing) sugars to the formulation of wall materials. The FTIR and DSC analyses revealed no chemical interaction between fish oil and SMP in the structure of fish oil microcapsule. The microcapsules were regular round spheres without any cracks and fissures. Acknowledgement The authors would like to extend their appreciation for the financial support provided by the University of Tehran. References Aghbashlo, M., Mobli, H., Rafiee, Sh, & Madadlou, A. (2012). Energy and exergy analyses of the spray drying process of fish oil microencapsulation. Biosystems Engineering, 111(2), Ahn, J.-H., Kim, Y.-P., Lee, Y.-M., Seo, E.-M., Lee, K.-W., & Kim, H.-S. (2008). Optimization of microencapsulation of seed oil by response surface methodology. Food Chemistry, 107(1), AOAC. (1984). AOAC Official analytical methods. Gaithersburg, MD: AOAC International. AOCS. (1993). AOCS Official method Cd In F. Gunstone (Ed.), Official methods and recommended practices of the American Oil Chemists Society method Cd Peroxide value acetic acid chloroform method (4th ed.). Champaign, IL: AOCS Press. Augustin, M. A., Sanguansri, L., & Bode, O. (2006). Maillard reaction products as encapsulants for fish oil powders. Journal of Food Science, 71(2), Bhandari, B. R., Dumoulin, E. D., Richard, H. M. J., Noleau, I., & Lebert, A. M. (1992). Flavor encapsulation by spray drying Application to citral and linalyl acetate. Journal of Food Science, 57(1), Chegini, G. R., & Ghobadian, B. (2005). Effect of spray-drying conditions on physical properties of orange juice powder. Drying Technology, 23(3), Desai, K. G. H., & Park, H. J. (2005). Recent developments in microencapsulation of food ingredients. Drying Technology, 23(7), Drusch, S., Serfert, Y., & Schwarz, K. (2006). Microencapsulation of fish oil with n-octenylsuccinate-derivatised starch: Flow properties and oxidative stability. European Journal of Lipid Science and Technology, 108(6), Drusch, S., Serfert, Y., Van Den Heuvel, A., & Schwarz, K. (2006). Physicochemical characterization and oxidative stability of fish oil encapsulated in an amorphous matrix containing trehalose. Food Research International, 39(7), Drusch, S., Serfert, Y., Scampicchio, M., Schmidt-Hansberg, B., & Schwarz, K. (2007). Impact of physicochemical characteristics on the oxidative stability of fish oil microencapsulated by spraydrying. Journal of Agricultural and Food Chemistry, 55(26), Fang, Z., & Bhandari, B. (2010). Encapsulation of polyphenols A review. Trends in Food Science & Technology, 21(10), Gharsallaoui, A., Roudaut, G., Chambin, O., Voilley, A., & Saurel, R. (2007). Applications of spray-drying in microencapsulation of food ingredients: An overview. Food Research International, 40, Goula, A. M., Adamopoulos, K. G., & Kazakis, N. A. (2004). Influence of spray drying conditions on tomato powder properties. Drying Technology, 22(5), Kagami, Y., Sungimura, S., Fujishima, N., Matsuda, K., Kometani, T., & Matsumura, Y. (2003). Oxidative stability, structure, and physical characteristics of microcapsules formed by spray drying of fish oil with protein and dextrin wall materials. Journal of Food Science, 68(7), Keogh, M. K., O Kennedy, B. T., Kelly, J., Auty, M. A., Kelly, P. M., Fureby, A., & Haahr, A. M. (2001). Stability to oxidation of spray-

9 Food Bioprocess Technol (2013) 6: dried fish oil powder microencapsulated using milk ingredients. JournalofFoodScience,66(2), Klaypradit, W., & Huang, Y.-W. (2008). Fish oil encapsulation with chitosan using ultrasonic atomizer. LWT- Food Science and Technology, 41(6), Kolanowski, W., Ziolkowski, M., Weißbrodt, J., Kunz, B., & Laufenberg, G. (2006). Microencapsulation of fish oil by spray drying Impact on oxidative stability. Part 1. European Food Research and Technology, 222(3 4), Liu, X. D., Furuta, T., Yoshii, H., & Linko, P. (2000). Retention of emulsified flavor in a single droplet during drying. Food Science and Technology Research, 6(4), Madadlou, A., Mousavi, M. E., Emam-djomeh, Z., Ehsani, M., & Sheehan, D. (2009). Sonodisruption of re-assembled casein micelles at different ph values. Ultrasonics Sonochemistry, 16(5), Moreau, D. L., & Rosenberg, M. (1996). Oxidative stability of anhydrous milk fat microencapsulated in whey proteins. Journal of Food Science, 61(1), Quek, S. Y., Chok, N. K., & Swedlund, P. (2007). The physicochemical properties of spray-dried watermelon powders. Chemical Engineering and Processing, 46(5), Reineccius, G. A. (2004). The spray drying of food flavors. Drying Technology, 22(6), Rosenberg, M., & Sheu, T.-Y. (1996). Microencapsulation of volatiles by spray-drying in whey protein-based wall systems. International Dairy Journal, 6(3), Serfert, Y., Drusch, S., Schmidt-Hansberg, B., Kind, M., & Schwarz, K. (2009). Process engineering parameters and type of n-octenylsuccinate-derivatised starch affect oxidative stability of microencapsulated long chain polyunsaturated fatty acids. Journal of Food Engineering, 95(3), Shahidi, F., & Han, X. Q. (1993). Encapsulation of food ingredients. Critical Reviews in Food Science and Nutrition, 33(6), Shen,Z.,Augustin,M.A.,Sanguansri,L.,&Cheng,L.J.(2010). Oxidative stability of microencapsulated fish oil powders stabilized by blends of chitosan, modified starch, and glucose. Journal of Agricultural and Food Chemistry, 58(7), Tonon, R. V., Grosso, C. R. F., & Hubinger, M. D. (2011). Influence of emulsion composition and inlet air temperature on the microencapsulation of flaxseed oil by spray drying. Food Research International, 44(1), Young, S. L., Sarda, X., & Rosenberg, M. (1993). Microencapsulating properties of whey proteins. 2. Combination of whey proteins with carbohydrates. Journal of Dairy Science, 76(10),