Eur Food Res Technol (2009) 229:391–396DOI 10.1007/s00217-009-1064-6 ORIGINAL PAPER Study on microencapsulation of curcumin pigments by spray drying Yu Wang Æ Zhaoxin Lu Æ Fengxia Lv Æ Xiaomei Bie Received: 13 November 2008 / Revised: 25 March 2009 / Accepted: 30 March 2009 / Published online: 18 April 2009 Ó Springer-Verlag 2009 Abstract Curcumin has strong coloring power, safety and innocuity, comprehensive pharmacological function, but its low stability and water insoluble limit its application. Curcumin microcapsules were prepared by spraydrying process using porous starch and gelatin as wall material here. Results showed optimal condition as follows: the ratio of core and wall material of 1/30, embedding temperature of 70 °C, embedding time 2 h, inlet gas temperature of 190 °C, feed flow rate 70 mL/min and drying air flow 70 m3/h, at which the microencapsules had good encapsulation efficiency. The stability of microencapsulation curcumin against light, heat, pH was effectively improved and its solubility was increased greatly. This study would be helpful to the industrial application of curcumin. Keywords Curcumin Pigment Microencapsulation Spray drying Stability Introduction Natural pigment is a vital quality attribute of foods, and plays an important role in sensory and consumer acceptance of products [8, 28, 29].Curcumin is an important permitted natural colorant used in food, nutritious and pharmaceutical preparations among others [22, 26]. It is a fat soluble pigment, while it is insoluble in aqueous medium [10]. It is susceptible to oxidants, light and heat, which can be easily deteriorated when exposed to such factors as Y. Wang (&) Z. Lu F. Lv X. Bie College of Food Science and Technology, Nanjing Agricultural University, 210095 Nanjing, China e-mail:
[email protected] pH, temperature, light, metallic ions, enzymes, oxygen, and ascorbic acid [27]. Because of its low stability, it cannot really be widely used in the food processing industry [10]. Microencapsulation has been widely used for the stabilization of labile compounds [7, 13]. It is defined as a process in which tiny particles or droplets are surrounded by a coating, or embedded in homogeneous or heterogeneous matrix, to give small capsules with many useful properties [17, 21]. In systems, stabilization occurs because the wall material acts as physical and a permeability barrier for molecular oxygen and other molecular diffusion [3, 11, 14, 23], consequently, the shelf life of the encapsulated products could be prolonged. Various kinds of microencapsulation techniques such as spray drying, spray cooling, extrusion, centrifugal extrusion, freeze drying, molecular inclusion among others, have been developed, among which, spray drying is the most commonly used one due to its low cost, available equipment, continuous production and easiness of industrialization, solid dispersions of curcumin in different ratios with PVP prepared by spray drying can improve its bioavailability such as its limited aqueous solubility and degradation at alkaline pH, but it give no further research for its property study, which limits its industrialization[1, 6, 16, 20]. Microencapsulation efficiency and microcapsules stability are largely dependent on wall material composition [15, 16, 30]. Wall materials can be selected from a wide variety of natural and synthetic polymers such as natural gum, proteins and maltodextrins. Among them, gelatin is a good choice due to its good properties of film-formation, water-solubility, edibility, biodegradation and a tendency to form a fine dense network upon drying, results of study indicate that microencapsulation using gelatin simple coacervation method can reduce the color staining effect 123 Eur Food Res Technol (2009) 229:391–396 dissolve in acetone (solution concentration is 10%). Materials and methods Table 1 Orthogonal design for the optimization of curcumin microencapsulation Wall and core materials Number Tet (°C) Mc/Mw tet (h) EE (%) 1 (1) 60 (1) 1:20 (2) 1. Microencapsulation process Gelatin (purity 96%) and porous starch (purity 98%) were dissolved in hot distilled water. 1. and 1/40). the low evaporation rate causes the formation of microcapsules with high density membranes. Tet. Curcumin sample. and 200 °C. Waf. China) and porous starch (Chongqing Taiwei Ecoagriculture Ltd.5 93.4% Wall materials used here included edible gelatin (G200.5 73.8 7 (3) 80 (1) 1:20 (3) 2 67. Ltd. 1/20. preheated to 123 .9% 243. Air outlet temperature depends on the drying characteristics of the material. 60. Mc/Mw.4 4 (2) 70 (1) 1:20 (1) 1 92. 50. The ideal air outlet temperature for the microencapsulation of food ingredients such as flavors has been reported to be 50–80 °C [24].2% 256.8 8 (3) 80 (2) 1:30 (2) 1. Optimal spray-drying conditions must also be considered.1 6 (2) 70 (3) 1:40 (2) 1.0% 252. 27]: EE(% ) ¼ CE 100 CT ð1Þ where CT refers to total added curcumin mass and CE refers to the mass of curcumin in the microencapsulated. Samples of the spray-dried particles were collected during the experiments. Core materials used here were curcumin samples (Hangzhou Lvtian Biotechnology Ltd.4% K2 282. Air inlet temperature and flow rate is important. tet. 12. 70. high water content.9% 234. 60. air inlet temperature.5 and 2 h.2 9 (3) 80 (3) 1:40 (1) 1 57. The objective of this study is to develop a spray-drying method for preparation of curcumin microcapsules using gelatin as wall materials and to determine the effects of different spray-drying operational variable on the curcumin microcapsules to evaluate the effects on the properties of spray-dried powders and their stability. 1/30. feed rate. was dripped into the aqueous solution by stirring to form a coarse emulsion at the following conditions (shown in Table 1): embedding temperature.8% 241. a high-speed centrifugal atomizer. a cyclone separator.0 2 (1) 60 (2) 1:30 (1) 1 83. When the feed temperature is increased. Among the main factors that must be optimized are feed temperature. viscosity and droplets size should be decreased but high temperatures can cause volatilization or degradation of some heat-sensitive ingredients. Shanghai Chemical Reagent Corporation. embedding time. plus a hot air blower and an exhaust blower. 1. The emulsion was then fed to the spray dryer at the following conditions (shown in Table 2): feed flow rate of microencapsulating composition. low rate and air outlet temperature [2]. The rate of feed is adjusted to ensure that each sprayed droplet reaches the desired drying level before it comes in contact with the surface of the drying chamber [25].392 and enhance the stability of curcumin. 60 and 70 m3/h. and 80 mL/min. and easiness of agglomeration [18]. to form an aqueous solution containing different ratios of gelatin and porous starch (mass ratio of core to wall material. 190. Tgi. poor fluidity. When the air inlet temperature is low. Wff. Shanghai.6 K1 252.5 3 (1) 60 (3) 1:40 (3) 2 94. being stirred.1 5 (2) 70 (2) 1:30 (3) 2 96.3% 16. 9. China).5 75. but it give no technological parameter for its industrialization [5. Analysis The encapsulation efficiency The encapsulation efficiency (EE) was calculated as follows [4. drying air flow. which are valuable for the advancement of drying technology and give technological parameter for its industrialization in the food industry.9% K3 Range 208. The air inlet temperature which can safely be used without damaging the product or creating operating hazards and the comparative cost of heat sources. 70.8% 73. China). 180.1% 258.0% 21. 19]. inlet gas temperature. China) equipped with a spray-drying chamber with dimensions of 150 cm height and 80 cm diameter. and 80 °C.. Spray-drying process The emulsion were carried out on a Model YC-105 Spray Dryer (Pilotech Instrument & Equipment Co. Effect of illumination time on light stability The mixture of the powder in the water solution (0.0.0% 267.0% K3 272. 16 and 30 days. the standard curcumin solution was obtained. 1.2 7 8 (3) 200 (3) 200 (1) 60 (2) 70 (3) 70 (1) 50 90. by which the mass of curcumin in the encapsulated was calculated.8 4 (2) 190 (1) 60 (2) 60 86. 3. respectively.1% Range 38. which restricts its application in acid food. 4.1% 251. the absorbance values of them were determined at 425 nm. 40 and 50 min. 70.4% K2 277.8 5 (2) 190 (2) 70 (3) 70 98. 1. 1.5% w/v) was prepared. When it is in alkali condition. 60. ti.0. The solubility of curcumin The curcumin solubility in water was determined as follows. its R2 was 0. Absorbance values were determined using the previously described technique. 2. 6. respectively.9 93. 90 and 100 °C. Its standard curve and regression equation were then achieved. The results were conducted in triplicate.34% 279. 20.1% is in the 123 . 10.4% 263. Ten-milliliter solutions were regulated to pH 1.1 K1 239. Th. respectively.7% Quantification of curcumin Twenty milligrams of microcapsule sample was dissolved in absolute alcohol to form homogeneous solution (solution concentration is 20%). the absorbance value of them were determined by the spectrophotometry at kmax = 425 nm. 80.0. 0.0 mL standard solutions were up to 10 mL constant volume. 6 and 7 with 1 mol/L hydrochloric acid. Effect of pH on acid fastness stability Curcumin can easily be deposited at the acidity condition.9998. 12.0% 258. the alkali fastness stability have not studied because of it. Curcumin concentration in the sample was calculated using absorption value of the standard solution. The powder was considered soluble when the time of solubilization was not greater than 5 min.Eur Food Res Technol (2009) 229:391–396 393 Table 2 Orthogonal design for the optimization of spray-drying operation conditions Number Tgi (°C) Wff (mL/min) Waf (m3/h) EE (%) 1 (1) 180 (1) 60 (1) 50 73. its color turns into russety. whose absorbances were determined by the 752 UV spectrophotometry at kmax = 425 nm. Furthermore. 8.0 9 (3) 200 (3) 80 (2) 60 88.1 3 (1) 180 (3) 80 (3) 70 77. The best of EE 96. Its regression equation was as follows: Y ¼ 12:278X þ 0:3281 ð2Þ where X referred to the absorbance value and Y referred to the concentration of curcumin.4 6 (2) 190 (3) 80 (1) 50 92. China) at kmax = 425 nm.0.3% w/v) was gently stirred until solid solubilization. The mixture of the powder in the water solution (0.3 2 (1) 180 (2) 70 (2) 60 88. In all. Ten-milliliter solutions were kept at 100 °C for a certain heating time. Ten-milliliter solutions were heated 10 min at a certain temperature. tht. Optimization of curcumin encapsulation process To determine the optimal condition of curcumin encapsulation process. respectively. 100 mL solutions were exposed in daylight for certain days (illumination time). The time necessary for complete microcapsule solubilization was recorded. Experimental design and results The standard curve is shown in Fig. Ten milligram of pure curcumin was dissolved in absolute alcohol and up to 100 mL constant volume.5. 2.5% w/v) was prepared. 4.3% 28. the absorbance values were also determined by the instrument. and 5. Improvement of its acid fastness is necessary. Evaluation of the curcumin stability Effect of heating temperature and heating time on heat resistance stability The mixture of the powder in the water solution (0.4% 8.0% 258. The mixture of the powder in the water solution (0. Its absorbance and mass was determined by a Model 752 UV spectrophotometry (Shanghai jinghua Instrument Ltd. the results of its orthogonal system was also shown in Table 1. 3.5% w/v) was prepared. 4. When it was up to 100 mL constant volume again. from which 10 mL solution was fetched. 30. Compared their absorbance values variation of curcumin at the temperature from 0 to 100 °C.258 Effects of heating temperature for 10 min on the stability of free curcumin.4 0.2 0.2 and 0. respectively. micro-encapsulated curcumin before and after spray drying were shown in Fig. along with increasing heating time. From pH 6 . Compared their K1. When encapsulated curcumin turned into powders after spray-drying process.266 0. Wff = 70 mL/min and Waf = 70 m3/h. absorbance values of free curcumin decreased rapidly while those of microencapsulated curcumin before and after spray drying leveled off. the optimal condition was Tgi = 190 °C.268 0. drying air flow was minor. powders was immediately resolved after 2 min. For three forms of curcumin. 2 h.274 absorbance value (A) 0. 0. free curcumin was not solved with water as solvent at normal temperature while encapsulated curcumin was resolved immediately after 4 min. 2.270 0. respectively. 70 °C. 3.8%. 2 Effect of heating temperature on curcumin stability 123 100 Effects of pH on the stability of free and microencapsulated curcumin before and after spray drying were shown in Fig. Effects of heating time at temperature 100 °C on the stability of free curcumin.3281 2 R = 0.9%.278x + 0. Optimization of curcumin spray-drying process The results of spray-drying operation condition were shown in orthogonal table (Table 2). tet.256 Effect of pH on acid fastness stability 0. There was no deposit in solution. 4. their orange color and lustre were stable.9998 5 4 3 2 1 0 The stability of curcumin 0.272 0. Along with increasing temperature.260 0. microencapsulated curcumin before and after spray drying were shown in Fig. The best of EE 98. the second was feed flow rate. so the optimal condition was as following: Tet.4% was in the experiment number 5.252 0 20 40 60 80 heating temperature ( ) Fig. whose color and luster of solution was vivid and transparent. K3 and range. when heating temperature was 100 °C.9 and 2. while these for microencapsulated curcumin before and after spray drying were 5.394 Eur Food Res Technol (2009) 229:391–396 The solubility of curcumin curcumin concentraiton (mg/L) 7 6 In the water-solubility experiment. K2. When their solutions were in condition from pH 6 to pH 1. while these for microencapsulated curcumin before and after spray drying were 1. absorbance values of free curcumin fell off rapidly while those of microencapsulated curcumin before and after spray drying declined tardily.5 Effect of heating temperature and heating time on heat resistance stability of curcumin aborbance value (A) Fig. microencapsulated curcumin had better heat resistance stability.262 0. the best important factor was inlet gas temperature. K2. Furthermore. the reducing ratio of absorbance value for free curcumin was 6. the reducing ratio of absorbance value for free curcumin was 25.276 0.254 0. Compared their absorbance values variation of curcumin from 10 to 50 min. 0.2%.264 microencapsulated curcumin before spray drying primary curcumin microencapsulated curcumin after spray drying 0.3 0.0 0. it demonstrated that the embedding temperature was the best important factor which effected on the encapsulation. Mc/Mw. the variation of temperature had no effect on curcumin stability. 1/30. When curcumin was microencapsulated. 1 The standard curve of curcumin solution experiment number 5. the heat resistance stability had been improved obviously. For curcumin. K3 and range. The solubility of encapsulated curcumin has further improved. while mass ratio of core to wall material and embedding time was relatively minor. when heating temperature was below 70 °C. y = 12. compared their K1.8%.1 0. 30 0.24 0.6%. Int J Pharm 271:281–286 123 . Mahadik K (2004) Characterization of curcumin-PVP solid dispersion obtained by spray dry.20 primary curcumin microencapsulated curcumin after spray drying 0. When their solutions were exposed to light. embedding time of 2 h. 5. Microencapsulation of curcumin had better acid fastness stability. This study would be helpful to promote the application of curcumin and the food industry.14 0 heating time (min) 10 15 20 25 30 illumination time (day) Fig. which were 1.21 0. 4 Effect of pH on acid fastness stability of curcumin to pH 4. while that of free curcumin is 15. Conclusion Curcumin microcapsules were successfully prepared by a spray-drying method using a wall system consisting of gelatin and porous starch. From 1 to 15 days. Anant P.25 0.18 microencapsulated curcumin after spray drying 0.18 10 20 30 40 50 0. feed flow rate of 70 mL/min and drying air flow of 70 m3/ h.16 microencapsulated curcumin before spray drying 0.Eur Food Res Technol (2009) 229:391–396 395 0.24 0. orange color was stable.22 0. it cut down. while from pH 4 to pH 1. References 1.3 and 2. the whole reducing ratio from 1 to 30 days was about 17.4%.22 0.19 0. absorbance value of free curcumin was invariable. Effect of illumination time on light stability Effects of illumination on the stability of free curcumin. 29972020). embedding temperature.7%. such as heat resistance stability.25 absorbance value (A) absorbance value (A) 0.26 0.9%. embedding temperature of 70 °C. Anshuman A.4 and 0. Acknowledgments This work was supported by the Youthful Scientific Innovation Foundation of Nanjing Agricultural University(no.23 1 2 3 4 5 6 pH Fig.27 0.23 0. while those of microencapsulated curcumin before and after spray drying were minor. Microencapsulation of curcumin also had better stability to illumination for a long time. inlet gas temperature and feed flow rate. at which microencapsulated curcumin before and after spray drying showed good solubility and stability. along with increasing illumination time from 15 to 30 days.29 absorbance value (A) 5 0. 3 Effect of heating time on curcumin stability at temperature 100 °C Fig. absorbance value of free curcumin kept stable. inlet gas temperature of 190 °C. From pH 6 to pH 1. the reducing ratio of absorbance value for microencapsulated curcumin before and after spray drying were 3.24 0. microencapsulated curcumin before and after spray drying were shown in Fig.28 microencapsulated curcumin before spray drying primary curcumin microencapsulated curcumin after spray drying 0. Bhimrao K.26 0. The optimal condition was determined as follows: the ratio of core and wall material of 1/30. acid fastness stability and light stability. 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