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Effects of high pressure extraction on the extraction yield, total phenolic content and antioxidant activity of longan fruit pericarp
Innovative Food Science and Emerging Technologies 10 (2009) 155–159
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Innovative Food Science and Emerging Technologies j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / i f s e t
Effects of high pressure extraction on the extraction yield, total phenolic content and antioxidant activity of longan fruit pericarp K. Nagendra Prasad a, En Yang a, Chun Yi a, Mouming Zhao b, Yueming Jiang a,⁎ a b
South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, People's Republic of China College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510650, People's Republic of China
a r t i c l e
i n f o
Article history: Received 29 July 2008 Accepted 22 November 2008 Keywords: Antioxidant Extraction yield High pressure Longan fruit Phenolics
a b s t r a c t High pressure extraction (HPE) was carried out to extract phenolic compounds from longan fruit pericarp. The influence of different solvents, solvent concentration (25−100%, v/v), solid to liquid ratio (1:25−1:100, w/v) were individually determined using these optimum extraction conditions. HPE was carried out at various pressures (200−500 MPa), durations (2.5−30 min) and temperatures (30−70 °C). The extraction yield, total phenolic contents and scavenging activities of superoxide anion radical and 1,1-dipheny l-2-picrylhydrazyl (DPPH) radical of HPE extract were examined and then compared with those of the conventional extraction (CE). The application of HPE obtained a higher extraction yield and required a less extraction time when compared to CE. Furthermore, the total phenolic contents and the antioxidant activities of HPE extract were higher than CE extract. This study indicated that this new technology can benefit the food and pharmaceutical industries. Industrial relevance: This study focused on the evaluations of the extraction yield, total phenolic content and antioxidant activity of longan fruit pericarp by high pressure treatment. The high pressure extraction technology provided a better way of utilizing longan fruit pericarp as a readily accessible source of natural antioxidants in food and pharmaceutical industries. © 2008 Elsevier Ltd. All rights reserved.
1. Introduction The interest in bioactive components from fruits and vegetables has increased greatly in recent years. Bioactive components from fruits and vegetables are preferred over synthetic ones due to the safety (Namiki, 1990). During processing of longan fruit, great quantity of fruit pericarp is generated. However, these pericarp is still a good and cheap source of high quality bioactive compounds like polyphenols, flavonoids, hydrolysable tannins and polysaccharides (Rangkadilok, Worasuttayangkurn, Bennett, & Satayavivad, 2005; Rangkadilok, Sitthimonchai, Worasuttayangkurn, Mahidol, Ruchirawat, & Satayavivad, 2007; Yang, Zhao, Shi, Yang, & Jiang, 2008) which exhibit antibacterial, antiviral, antioxidant, anti-inflammatory and anti-carcinogenic activities (Bravo, 1998; Soong & Barlow, 2006). Extraction is a very important step in isolating these bioactive compounds. There are many reports about different extraction methods from longan fruit pericarp (LFP), such as soxhlet and microwave extraction (Pan et al., 2008), ultrasonics (Yang et al., 2008) and solid phase microextraction (Zhang & Li, 2007). These methods are largely based on an appropriate selection of solvent and energy input to increase the chemical solubility and the rate of mass transfer. Usually, these methods can require high energy consumption and the extraction yield are relatively low with long extraction time (Zhang, Junjie, & Changzhen, 2004). ⁎ Corresponding author. Tel.: +86 20 37252525; fax: +86 20 37253821. E-mail address: [email protected] (Y. Jiang). 1466-8564/$ – see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.ifset.2008.11.007
High pressure extraction (HPE) as a novel technique is used for extraction of active ingredients from plant materials. High pressure ranging from 100 to 800 MPa or even more up to 1000 MPa is considered as an alternative extraction method, which is proven to be fast and more effective (Zhang et al., 2004). High pressure can cause some structural changes in foods, such as cellular deformation, cellular membrane damage and protein denaturation (Zhang, Xi, & Wang, 2005). High pressure can also improve the mass transfer rate, enhance solvent permeability in cells as well as secondary metabolite diffusion (Dornenburg & Knorr, 1993; Ahmed & Ramaswamy, 2006). Recently, some authors (Zhang et al., 2004, 2005; Corrales, Toepfl, Butz, Knorr, & Tauscher, 2008) have reported that HPE technique can reduce the processing time and obtain higher extraction yield. Thus, HPE has some advantages for extraction of natural products. Furthermore, this technology has been used successfully for the extraction of flavonoids from propolis (Zhang et al., 2005), anthocyanins from grape skin (Corrales, Toepfl, et al., 2008) and ginsenosides from the roots of Panax ginseng (Zhang, Ruizhan, & Changzheng, 2007). Unfortunately, there is no information on the usage of the high pressure extraction (HPE) of LFP. The major objective of this study was to build up and optimize HPE method to extract bioactive compounds from LFP, and then to compare the effectiveness of HPE with conventional extraction (CE) based on their extraction yields, total phenolic contents and antioxidant activities. This study could help better utilize longan fruit pericarp as a readily accessible source of natural antioxidants in food or pharmaceutical industry.
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2. Materials and methods 2.1. Plant materials Fresh fruits of longan (Dimpcarpus longan Lour.) cv. Shixia at the commercial mature stage were chosen from a commercial orchard and then selected for regularity of shape and color. These fruits were washed with tap water before they were manually peeled and separated. Finally, the LFP tissues were dried for 24 h in a hot air oven at 60 °C and powdered using a blender.
solution (1.3 μM riboflavin, 0.02 M methionine and 5.1 μM nitro blue tetrazolium, pH 7.4). The reaction solution was illuminated for 20 min at 25 °C and the absorbance was then measured at 560 nm using a spectrophotometer (UV-2802, Unico Co Ltd, Shanghai, China). Ascorbic acid and butylated hydroxytoluene (BHT) were used as the positive controls while the reaction mixture without any extract was used as a control. The scavenging activity of superoxide anion radical was calculated as the percentage (%) = (1 − absorbance of sample / absorbance of control) × 100. 2.8. DPPH radical scavenging activity
2.2. Chemicals and reagents 1,1-Diphenl-2-picryldydrazyl (DPPH), ascorbic acid, butylated hydroxy toluene (BHT), nitro blue tetrazolium (NBT), methionine, riboflavin and gallic acid were purchased from Sigma Chemical Co. (St Louis, MO, USA). All other chemicals and solvents used for the extraction in this study were of analytical grade and obtained from Tianjin Reagent Company (Tianjin, China). 2.3. High pressure extraction High pressure extraction was performed with high hydrostatic pressure food processor (Kefa Food Equipment Ltd, Baotou, China). The dried LFP powder (10 g) was mixed with 500 mL of 50% ethanol, and then pressurized at a given pressure (200, 300, 400 or 500 MPa), time (2.5, 5, 10, 15 or 30 min.) and temperature (30, 50 or 70 °C). The pressure chamber was controlled at a constant temperature by a water bath device. Pressurization cycle, pressure and time were programmed by a computer. After de-pressurization, the extracted solution was collected and then filtered. The obtained filtrate was stored at 4 °C in refrigerator for further analysis.
The DPPH radical scavenging activity of each extract was evaluated by the method of Moon and Terao (1998) with some modification. Initially, 0.2 mL of each sample at 50 or 100 μg/mL was mixed with 0.8 mL of Tris–HCl buffer (pH 7.4) and 1 mL of DPPH (500 μM in ethanol) was then added to the mixture. After the mixture was shaken briskly and left to stand for 40 min in dark, the absorbance was measured at 517 nm in a spectrophotometer (UV-2802, Unico Co Ltd, Shanghai, China). All the samples were tested in triplicate while ascorbic acid and BHT were used as the positive controls. The control consisted of all reagents and solvents without any extract while ethanol was used as the blank. The inhibition of DPPH radical by the tested sample was calculated as the scavenging activity (%) = (1 − absorbance of sample / absorbance of control) × 100. 2.9. Statistical analysis Data were expressed as means ± standard deviations (SD) of three replicate determinations and then analyzed by SPSS V.13. Duncan's new multiple-range test was used to determine the significant differences of means at the 5% level.
2.4. Conventional extraction
3. Results and discussion
Conventional extraction (CE) was carried out by the method of Corrales, Toepfl et al. (2008) with minor modification. The dried LFP powder (10 g) was extracted for 12 h using a magnetic stirrer with 500 mL of given solvents in a conical flask at 30 °C. The solvents were replaced periodically every 4 h. The extraction solution was filtered and the filtrate was collected and stored at 4 °C.
The factors concerning the HPE included solvent, solvent concentration, ratio of solid/liquid, pressure, time and temperature. The influence of each factor was analyzed by a single factor experiment.
2.5. Extraction yield The extraction yield was calculated by the method of Zhang, Bi, and Liu (2007). In brief, the obtained filtrate was evaporated to dryness by a rotary evaporator (RE-52A, Shanghai Woshi Co., Shanghai, China) under vacuum at 60 °C and then lyophilized in a freeze-dryer (Savant, Vapornet VN 100, Labequip Ltd., Cannada) to obtain a freeze-dried extract. The dried extract was weighed, and then the extraction yield was calculated and expressed as the percentage of the weight of the crude extract to the raw material (10 g).
3.1. The effects of different solvents on the extraction yield and total phenolic content Conventional extraction was carried out using four various types of solvents (ethyl-acetate, ethanol, methanol and water) to extract phenolic compounds from LFP. Fig. 1 shows that application of ethanol or methanol exhibited the highest total phenolic content, followed by water and ethyl acetate. Ethyl acetate is usually used for extraction of
2.6. Determination of total phenolic content Total phenolic content of each extract was determined using the standard gallic acid calibration curve by the method of Prasad, Divakar, Shivamurthy, and Aradhya (2005). Total phenolic content of each extract was expressed as mg/g on dry weight (DW) basis. 2.7. Determination of superoxide anion radical scavenging activity Superoxide anion radical scavenging activity was analyzed by the method of Duan, Wu, and Jiang (2007) with some modifications. All solutions were prepared in 0.2 M phosphate buffer (pH 7.4). Each extract at 50 or 100 μg/mL was mixed with 3 mL of reaction buffer
Fig. 1. The total phenolic content and extraction yield from longan fruit pericarp by conventional extraction for 12 h using various solvents and 1:50 (w/v) solid/liquid ratio at 30 °C. For each treatment means in a row followed by different letters were significantly different at the 5% level.
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flavonoid aglycones while ethanol, methanol and water are used for medium polar and polar compounds such as flavonoid glycoside, phenolic acids, polysaccharides and sugars depending upon their polarity (Jayaprakasha, Girennavar, & Patil, 2008). Because of difference in polarity of the extraction solvents, the solubility of phenolic compounds and the rate of mass transfer could be different (Bi, Zhang, Liu, & Wang, 2008). As flavonoids and phenolic acids are more soluble in methanol than ethanol, it is reasonable to obtain a higher extraction yield when methanol is used (Markham, 1982). Because ethanol is less toxic than methanol and easy for recycling, it was chosen for the subsequent experiments. 3.2. The effects of ethanol concentrations on the extraction yield and total phenolic content Ethanol at 25−100% (v/v) was used to extract phenolic compounds from LFP by CE. Generally, 40–50% ethanol has a greater effectiveness in extracting polyphenolic compounds compared to pure ethanol (Jayaprakasha et al., 2008). Total phenolic content and extraction yield from LFP was influenced greatly by ethanol concentrations (Fig. 2). When ethanol concentration increased from 25 to 50%, the increases in the phenolic content (14.2 ± 0.2 mg/g) and extraction yield (14.8 ± 0.6%) were observed, which was probably due to the increased solubility of flavonoids, phenolic compounds, hydrolysable tannins and polysaccharides in the mixture of ethanol and water. Spigno, Tramelli, and Faveri (2007) reported higher extraction yield and phenolic content from grape seeds when 50% ethanol was used. However, when ethanol concentration was higher than 75%, the extraction yield decreased. As the solvent may influence cellular structures (Zhang, Ruizhan, et al., 2007), 50% ethanol was used for the subsequent study. 3.3. The effects of solid to liquid ratio on the extraction yield and total phenolic content 50% ethanol was used to extract phenolic compounds from LFP by CE in this study. The total phenolic content and extraction yield increased with increasing solid to liquid ratio (m/v). When the solid to liquid ratio increased from 1:25 to 1:50, the total phenolic content and extraction yield increased from 12.1 ± 0.1 to 14.2 ± 0.2 mg/g DW and 13.5 ± 0.4 to 14.8 ± 0.6%, respectively (Fig. 3), which is probably due to the fact that more solvent can enter cells while more phenolic compounds can permeate into the solvent under the higher solid to liquid ratio condition (Zhang, Bi, et al., 2007). Kojic, Planinic, Tomas, Bilic, and Velie (2007) obtained higher polyphenol content from grape seeds when a solid to liquid ratio of 1:40 (m/v) was used. Although the solid to liquid ratio is useful for increasing the extraction yield, further
Fig. 2. The phenolic content and extraction yield from longan fruit pericarp by conventional extraction for 12 h using various ethanol concentrations and 1:50 (w/v) solid/liquid ratio at 30 °C. For each treatment means in a row followed by different letters were significantly different at the 5% level.
Fig. 3. The phenolic content and extraction yield from longan fruit pericarp by conventional extraction for 12 h using various solid/liquid (w/v) ratios using 50% ethanol at 30 °C. For each treatment means in a row followed by different letters were significantly different at the 5% level.
increase in the solid to liquid ratio did not improve greatly the total phenolic content. Therefore, the solid/liquid ratio of 1:50 (w/v) was used for the subsequent experiment. 3.4. The effects of high pressure on the extraction yield and total phenolic content 50% ethanol and a solid to liquid ratio of 1:50 (w/v) were used to extract phenolic compounds from LFP by HPE for 30 min. As shown in Fig. 4, the extraction yield and total phenolic content were greatly influenced by high pressure treatment. Compared to conventional extraction, the extraction yield increased from 14.8 ± 0.4 to 17.8 ± 0.4% when 500 MPa HPE was used. Also, the total phenolic content increased from 14.6 ± 0.2 to 21 ± 0.6 mg/g DW. High pressure treatment can increase the rate of mass transfer, enhance solvent penetration into the cells by disrupting the cellular walls and hydrophobic bonds in the cell membrane which may lead to a high permeability (BarbosaCanovas, Pothakamury, Palou, & Swanson, 1998; Dornenburg & Knorr, 1993; Oey, Lille, Loey, & Hendrickx, 2008). HPE can also cause deprotonation of charged groups, and distraction of salt bridges and hydrophobic bonds, resulting in conformational changes and denaturation of proteins and then rendering these phenolics compounds more available to extraction up to equilibrium (Barbosa-Canovas et al., 1998). Based on the phase behavior theory, the solubility of these compounds increased as the pressure increased (Richard, 1992). Thus, 500 MPa was used for the subsequent study.
Fig. 4. The phenolic content and extraction yield from longan fruit pericarp using conventional (control) and various high pressure extraction for 12 h and 30 min respectively, 50% ethanol and 1:50 (w/v) solid/liquid ratio at 30 °C. For each treatment means in a row followed by different letters were significantly different at the 5% level.
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K.N. Prasad et al. / Innovative Food Science and Emerging Technologies 10 (2009) 155–159 Table 1 A comparison of scavenging activities of superoxide anion radical and DPPH radical of HPE and CE extracts from longan fruit pericarp
CE extract HPE extract Ascorbic acid⁎ BHT⁎
Superoxide scavenging activity (%)
DPPH scavenging activity (%)
50 μg/mL
100 μg/mL
50 μg/mL
100 μg/mL
48.6 ± 2.9a 50.4 ± 0.9a 30.7 ± 2.7b 20 ± 3.5c
56.6 ± 2.3b 61.6 ± 1.1a 42 ± 2c 23 ± 1.7d
50.1 ± 0.2c 75 ± 0.2 b 80 ± 2 a 77.4 ± 2 a
76.6 ± 0.5b 77.7 ± 0.2a 80.4 ± 0.6a 80 ± 1a
Conventional extraction (CE): 50% ethanol, 1:50 (w/v) solid/liquid ratio and 12 h of extraction time at 30 °C and high pressure extraction (HPE): 50% ethanol, 1:50 (w/v) solid/liquid ratio, 500 MPa pressure and 2.5 min of extraction time at 30 °C. For each treatment means within a column followed by different letters were significantly different at the 5% level. ⁎Positive controls. Fig. 5. The phenolic content and extraction yield from longan fruit pericarp using various extraction time under 500 MPa, 50% ethanol and 1:50 (w/v) solid/liquid ratio at 30 °C. For each treatment means in a row followed by different letters were significantly different at the 5% level.
3.5. The effects of pressure holding time on the extraction yield and total phenolic content 50% ethanol, the solid to liquid ratio of 1:50 (w/v) and 500 MPa were used to examine the effects of various pressure holding time (2.5− 30 min) on phenolic compounds from LFP. Fig. 5 shows the effect of pressure holding time on the total phenolic content and extraction yield from LFP. The result indicated that the extraction yield and total phenolic content did not change significantly when extraction time increased from 2.5 to 30 min. According to the Pascal theory (Chen, Zhang, & Qian, 2005), the pressure transfers to the whole material uniformly and instantly during HPE process. Thus, the equilibrium of pressure between the inside and outside of the cells could occur in a very short time. Under these circumstances, the diffusion speed of the solvent is high while the extraction yield can reach the highest value very rapidly (Antonio & Gonzalo, 2005; Butz, Garcia, Lindauer, Dieterich, Bognar, & Tauscher, 2003). Similar results were reported by Zhang et al. (2005) and Prasad, Yang, Zhao, Wang, Chen, and Jiang (2008) to extract flavonoids from propolis and lychee, respectively. Therefore, an HPE time of 2.5 min was used for the following experiment. 3.6. The effects of high pressure temperature on the extraction yield and total phenolic content 50% ethanol, the solid to liquid ratio of 1:50 (w/v), 500 MPa and 2.5 min of extraction time was used to extract phenolic compounds
from LFP in this study. The extraction yield increased with increasing temperature (Fig. 6). When extraction temperature increased from 30 to 50 °C, the extraction yield increased from 17.6 ± 0.4 to 30 ± 0.8%. Similarly, the total phenolic content also increased from 21 ± 0.6 to 23 ± 0.3 mg/g DW. A rise in extraction temperature can break the phenolicmatrix bonds and influence the membrane structure of plant cells making them less selective by coagulation of lipoproteins (Fernandez, Goodwin, Lemmon, Levelt-sengers, & Williams, 1997). The dielectric constant of water decreases and solvent property and capacity change at higher temperature, resulting in a better extraction of phenolics (Corrales, Garcia, Butz, & Tauscher, 2008). However, further increase in extraction temperature could degrade phenolic compounds (Durling et al., 2007). 3.7. Comparison of HPE and CE In association with the further effectiveness in evaluating these extraction methods, the antioxidant activity was analysed (Table 1). The antioxidant activity of the samples obtained by HPE was higher than CE in the two system tested. The highest scavenging activity of superoxide anion radical was obtained for HPE (61.6 ± 1.1) while the lowest activity (23 ± 1.7) was observed for BHT as a concentration of 100 μl/mL was used. Similarly, the DPPH scavenging activity of HPE extract at 50 μg/mL was 75 ± 0.2%, which was comparable to BHT, whereas CE extract was only 50.1 ± 0.2%. The antioxidant activity of HPE or CE extract is in accordance with the amount of phenolic compounds. The phenolic compounds exhibit extensive free radical scavenging activities through their reactivity as hydrogen or electron-donating agents, and metal ion chelating properties (Rice-Evans, Miller, & Paganga, 1996). LFP contains a high amount of polar compounds like phenolic acids, flavonoids and polysaccharides which are good antioxidant compounds (Soong & Barlow, 2006; Rangkadilok et al., 2007). Using high pressure treatment, these compounds can be extracted efficiently due to increase in solvent power, solvent density and solubility of polar compounds. In addition, high pressure processing can cause enhancement of chemical and biochemical reactions in the cells by both desired and undesired modification (Oey et al., 2008). Moreover, high pressure treatment provides the possibility of inactivating degrading enzymes which may account for higher extraction yield and antioxidant activity compared to other methods. 4. Conclusions
Fig. 6. The phenolic content and extraction yield from longan fruit pericarp using various extraction temperatures under 500 MPa, 2.5 min, 50% ethanol and 1:50 (w/v) solid/liquid ratio. For each treatment means in a row followed by different letters were significantly different at the 5% level.
Conditions for HPE on extraction yield from LFP were investigated. Compared with the conventional extraction method, HPE provided higher extraction yield and required less extraction time. The higher total phenolic content and the stronger antioxidant activity of LFP by HPE were also obtained as compared with the conventional extraction. Thus, HPE could be an alternative method for extracting bioactive compounds from LFP to the conventional extraction. Further investigation of
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a comparison of the operation cost between HPE and CE can be needed for commercial usage. Acknowledgements This work was supported by the National Natural Science Foundation of China (Grant Nos. 30425040 and 30700557). References Ahmed, J., & Ramaswamy, H. S. (2006). High pressure processing of fruits and vegetables. Stewart Postharvest Review, 1, 1−10. Antonio, T. J., & Gonzalo, V. G. (2005). Commercial opportunities and research challenges in the high pressure processing of foods. Journal of Food Engineering, 67, 95−112. Barbosa-Canovas, G.V., Pothakamury, U.R., Palou, E., & Swanson, B.G. (1998). Nonthermal preservation of foods (pp. 9–52, 139–213), New York: Marcel Dekker. Bi, H. M., Zhang, S., Liu, C., & Wang, C. Z. (2008). High hydrostatic pressure extraction of salidroside from Rhodiola Sachalinensis. Journal of Food Process Engineering. doi:10.1111/j.1745-4530.2007.00202 Bravo, I. (1998). Polyphenols: chemistry, dietary sources, metabolism, and nutritional significance. Nutrition Reviews, 56, 317−333. Butz, P., Garcia, A. F., Lindauer, R., Dieterich, S., Bognar, A., & Tauscher, B. (2003). Influence of ultra high pressure processing on fruit and vegetable products. Journal of Food Engineering, 56, 233−236. Chen, E. S., Zhang, X., & Qian, X. M. (2005). Food ultrahigh pressure process technology (pp. 2−3). Beijing: Chemical Industry Publishing House. Corrales, M., Garcia, A. F., Butz, P., & Tauscher, B. (2008). Extraction of anthocyanins from grape skin assisted by high hydrostatic pressure. Journal of Food Engineering, 90(4), 415−421. doi:10.1016/j.jfoodeng Corrales, M., Toepfl, S., Butz, P., Knorr, D., & Tauscher, B. (2008). Extraction of anthocyanins from grape by-products assisted by ultrasonic, high hydrostatic pressure or pulsed electric fields: a comparison. Innovative Food Science and Emerging Technologies, 9, 85−91. Dornenburg, H., & Knorr, D. (1993). Cellular permeabilization of cultured plant tissues by high electric field pulses or ultra high pressure for the recovery of secondary metabolites. Food Biotechnology, 7, 35−48. Duan, X., Wu, G., & Jiang, Y. (2007). Evaluation of antioxidant properties of phenolics from litchi fruit in relation to pericarp browning prevention. Molecules, 12, 759−771. Durling, N. E., Catchpole, O. J., Grey, J. B., Webby, R. F., Mitchell, K. A., Foo, L. Y., & Perry, N. B. (2007). Extraction of phenolics and essential oil from dried sage (Salvia officianlis) using ethanol-water mixtures. Food Chemistry, 101, 1417−1424. Fernandez, D. P., Goodwin, A. R. H., Lemmon, E. W., Levelt-sengers, J. M. H., & Williams, R. C. (1997). A formulation for the static permitivity of water and steam at temperature from 238 K to 873 K at pressures up to 1200 MPa, including derivatives and Deby–Hückel coefficients. Journal of Physical Chemistry, 26, 1125−1166. Jayaprakasha, G. K., Girennavar, B., & Patil, B. S. (2008). Radical scavenging activities of Rio Red grapefruits and sour orange fruit extracts in different in vitro model systems. Bioresource Technology, 99, 4484−4494. Kojic, A. B., Planinic, M., Tomas, S., Bilic, M., & Velie, D. (2007). Study of solid–liquid extraction kinetics of total polyphenols from grape seeds. Journal of Food Engineering, 81, 236−242.
159
Namiki, M. (1990). Antioxidants/antimutagens in foods. Critical Review in Food Science and Nutrition, 29, 273−300. Markham, K. R. (1982). Techniques of flavonoid identification. London: Academic Press. Moon, J. H., & Terao, J. (1998). Antioxidant activity of caffeic acid and dihydrocaffeic acid in lard and human low-density lipoprotein. Journal of Agricultural and Food Chemistry, 46, 5062−5065. Oey, I., Lille, M., Loey, A. V., & Hendrickx, M. (2008). Effect of high pressure processing on colour, texture and flavour of fruit and vegetable-based food products: a review. Trends in Food Science and. Technology, 19, 320−328. Pan, Y., Wang, K., Huang, S., Wang, H., Mu, X., He, C., Ji, X., Zhang, J., & Huang, F. (2008). Antioxidant activity of microwave-assisted extract of longan (Dimocarpus longan Lour.) peel. Food Chemistry, 106, 1264−1270. Prasad, N. K., Divakar, S., Shivamurthy, G. R., & Aradhya, S. M. (2005). Isolation of a free radical scavenging antioxidant from water spinach (Ipomoea aquatica Forsk). Journal of the Science of Food and Agriculture, 85, 1461−1468. Prasad, N. K., Yang, B., Zhao, M., Wang, B., Chen, F., & Jiang, Y. (2008). Effects of high pressure treatment on the extraction yield, phenolic content and antioxidant activity of litchi (Litchi chinensis Sonn.) fruit pericarp. International Journal of Food Science and. Technology. doi:10.1111/j.1365-2621.2008.01768.x Rangkadilok, N., Sitthimonchai, S., Worasuttayangkurn, L., Mahidol, C., Ruchirawat, M., & Satayavivad, J. (2007). Evaluation of free radical scavenging and antityrosinase activities of standardized longan fruit extract. Food and Chemical Toxicology, 45, 328−336. Rangkadilok, N., Worasuttayangkurn, L., Bennett, R. N., & Satayavivad, J. (2005). Identification and quantification of polyphenolic compounds in longan (Euphoria longana Lam.) fruit. Journal of Agricultural and Food Chemistry, 53, 1387−1392. Rice-Evans, C. A., Miller, N. J., & Paganga, G. (1996). Structure antioxidant activity relationship of flavonoids and phenolic acids. Free Radical Biololgy & Medicine, 20, 933−956. Richard, J. S. (1992). High pressure phase behavior of multi component fluid mixtures. Amsterdam: Elsevier. Soong, Y. Y., & Barlow, P. J. (2006). Quantification of gallic acid and ellagic acid from longan (Dimocarpus longan Lour.) seed and mango (Mangifera indica L.) kernal and their effects on antioxidant activity. Food Chemistry, 97, 524−530. Spigno, G., Tramelli, L., & Faveri, D. M. D. (2007). Effects of extraction time, temperature and solvent on the concentration and antioxidant activity of grape marc phenolics. Journal of Food Engineering, 81, 200−208. Yang, B., Zhao, M., Shi, J., Yang, E., & Jiang, Y. (2008). Effect of ultrasonic treatment on the recovery and DPPH radical scavenging activity of polysaccharides from longan fruit pericarp. Food Chemistry, 106, 685−690. Zhang, S., Junjie, Z., & Changzhen, W. (2004). Novel high pressure extraction technology. International Journal of Pharmaceutics, 78, 471−474. Zhang, S., Xi, J., & Wang, C. Z. (2005). Effect of high hydrostatic pressure on extraction of flavonoids in propolis. Food Science and Technology International, 11, 213−216. Zhang, Z. M., & Li, L. (2007). A preliminary study of plant aroma profile characteristics by a combination sampling method coupled with GC-MS. Microchemical Journal, 86, 29−36. Zhang, S., Bi, H., & Liu, C. (2007). Extraction of bio-active components from Rhodiola sachalinensis under ultrahigh hydrostatic pressure. Separation and Purification Technology, 57, 275−280. Zhang, S., Ruizhan, C., & Changzheng, W. (2007). Experiment study on ultrahigh pressure extraction of ginsenosides. Journal of Food Engineering, 79, 1−5.
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Innovative Food Science and Emerging Technologies j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / i f s e t
Effects of high pressure extraction on the extraction yield, total phenolic content and antioxidant activity of longan fruit pericarp K. Nagendra Prasad a, En Yang a, Chun Yi a, Mouming Zhao b, Yueming Jiang a,⁎ a b
South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, People's Republic of China College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510650, People's Republic of China
a r t i c l e
i n f o
Article history: Received 29 July 2008 Accepted 22 November 2008 Keywords: Antioxidant Extraction yield High pressure Longan fruit Phenolics
a b s t r a c t High pressure extraction (HPE) was carried out to extract phenolic compounds from longan fruit pericarp. The influence of different solvents, solvent concentration (25−100%, v/v), solid to liquid ratio (1:25−1:100, w/v) were individually determined using these optimum extraction conditions. HPE was carried out at various pressures (200−500 MPa), durations (2.5−30 min) and temperatures (30−70 °C). The extraction yield, total phenolic contents and scavenging activities of superoxide anion radical and 1,1-dipheny l-2-picrylhydrazyl (DPPH) radical of HPE extract were examined and then compared with those of the conventional extraction (CE). The application of HPE obtained a higher extraction yield and required a less extraction time when compared to CE. Furthermore, the total phenolic contents and the antioxidant activities of HPE extract were higher than CE extract. This study indicated that this new technology can benefit the food and pharmaceutical industries. Industrial relevance: This study focused on the evaluations of the extraction yield, total phenolic content and antioxidant activity of longan fruit pericarp by high pressure treatment. The high pressure extraction technology provided a better way of utilizing longan fruit pericarp as a readily accessible source of natural antioxidants in food and pharmaceutical industries. © 2008 Elsevier Ltd. All rights reserved.
1. Introduction The interest in bioactive components from fruits and vegetables has increased greatly in recent years. Bioactive components from fruits and vegetables are preferred over synthetic ones due to the safety (Namiki, 1990). During processing of longan fruit, great quantity of fruit pericarp is generated. However, these pericarp is still a good and cheap source of high quality bioactive compounds like polyphenols, flavonoids, hydrolysable tannins and polysaccharides (Rangkadilok, Worasuttayangkurn, Bennett, & Satayavivad, 2005; Rangkadilok, Sitthimonchai, Worasuttayangkurn, Mahidol, Ruchirawat, & Satayavivad, 2007; Yang, Zhao, Shi, Yang, & Jiang, 2008) which exhibit antibacterial, antiviral, antioxidant, anti-inflammatory and anti-carcinogenic activities (Bravo, 1998; Soong & Barlow, 2006). Extraction is a very important step in isolating these bioactive compounds. There are many reports about different extraction methods from longan fruit pericarp (LFP), such as soxhlet and microwave extraction (Pan et al., 2008), ultrasonics (Yang et al., 2008) and solid phase microextraction (Zhang & Li, 2007). These methods are largely based on an appropriate selection of solvent and energy input to increase the chemical solubility and the rate of mass transfer. Usually, these methods can require high energy consumption and the extraction yield are relatively low with long extraction time (Zhang, Junjie, & Changzhen, 2004). ⁎ Corresponding author. Tel.: +86 20 37252525; fax: +86 20 37253821. E-mail address: [email protected] (Y. Jiang). 1466-8564/$ – see front matter © 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.ifset.2008.11.007
High pressure extraction (HPE) as a novel technique is used for extraction of active ingredients from plant materials. High pressure ranging from 100 to 800 MPa or even more up to 1000 MPa is considered as an alternative extraction method, which is proven to be fast and more effective (Zhang et al., 2004). High pressure can cause some structural changes in foods, such as cellular deformation, cellular membrane damage and protein denaturation (Zhang, Xi, & Wang, 2005). High pressure can also improve the mass transfer rate, enhance solvent permeability in cells as well as secondary metabolite diffusion (Dornenburg & Knorr, 1993; Ahmed & Ramaswamy, 2006). Recently, some authors (Zhang et al., 2004, 2005; Corrales, Toepfl, Butz, Knorr, & Tauscher, 2008) have reported that HPE technique can reduce the processing time and obtain higher extraction yield. Thus, HPE has some advantages for extraction of natural products. Furthermore, this technology has been used successfully for the extraction of flavonoids from propolis (Zhang et al., 2005), anthocyanins from grape skin (Corrales, Toepfl, et al., 2008) and ginsenosides from the roots of Panax ginseng (Zhang, Ruizhan, & Changzheng, 2007). Unfortunately, there is no information on the usage of the high pressure extraction (HPE) of LFP. The major objective of this study was to build up and optimize HPE method to extract bioactive compounds from LFP, and then to compare the effectiveness of HPE with conventional extraction (CE) based on their extraction yields, total phenolic contents and antioxidant activities. This study could help better utilize longan fruit pericarp as a readily accessible source of natural antioxidants in food or pharmaceutical industry.
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2. Materials and methods 2.1. Plant materials Fresh fruits of longan (Dimpcarpus longan Lour.) cv. Shixia at the commercial mature stage were chosen from a commercial orchard and then selected for regularity of shape and color. These fruits were washed with tap water before they were manually peeled and separated. Finally, the LFP tissues were dried for 24 h in a hot air oven at 60 °C and powdered using a blender.
solution (1.3 μM riboflavin, 0.02 M methionine and 5.1 μM nitro blue tetrazolium, pH 7.4). The reaction solution was illuminated for 20 min at 25 °C and the absorbance was then measured at 560 nm using a spectrophotometer (UV-2802, Unico Co Ltd, Shanghai, China). Ascorbic acid and butylated hydroxytoluene (BHT) were used as the positive controls while the reaction mixture without any extract was used as a control. The scavenging activity of superoxide anion radical was calculated as the percentage (%) = (1 − absorbance of sample / absorbance of control) × 100. 2.8. DPPH radical scavenging activity
2.2. Chemicals and reagents 1,1-Diphenl-2-picryldydrazyl (DPPH), ascorbic acid, butylated hydroxy toluene (BHT), nitro blue tetrazolium (NBT), methionine, riboflavin and gallic acid were purchased from Sigma Chemical Co. (St Louis, MO, USA). All other chemicals and solvents used for the extraction in this study were of analytical grade and obtained from Tianjin Reagent Company (Tianjin, China). 2.3. High pressure extraction High pressure extraction was performed with high hydrostatic pressure food processor (Kefa Food Equipment Ltd, Baotou, China). The dried LFP powder (10 g) was mixed with 500 mL of 50% ethanol, and then pressurized at a given pressure (200, 300, 400 or 500 MPa), time (2.5, 5, 10, 15 or 30 min.) and temperature (30, 50 or 70 °C). The pressure chamber was controlled at a constant temperature by a water bath device. Pressurization cycle, pressure and time were programmed by a computer. After de-pressurization, the extracted solution was collected and then filtered. The obtained filtrate was stored at 4 °C in refrigerator for further analysis.
The DPPH radical scavenging activity of each extract was evaluated by the method of Moon and Terao (1998) with some modification. Initially, 0.2 mL of each sample at 50 or 100 μg/mL was mixed with 0.8 mL of Tris–HCl buffer (pH 7.4) and 1 mL of DPPH (500 μM in ethanol) was then added to the mixture. After the mixture was shaken briskly and left to stand for 40 min in dark, the absorbance was measured at 517 nm in a spectrophotometer (UV-2802, Unico Co Ltd, Shanghai, China). All the samples were tested in triplicate while ascorbic acid and BHT were used as the positive controls. The control consisted of all reagents and solvents without any extract while ethanol was used as the blank. The inhibition of DPPH radical by the tested sample was calculated as the scavenging activity (%) = (1 − absorbance of sample / absorbance of control) × 100. 2.9. Statistical analysis Data were expressed as means ± standard deviations (SD) of three replicate determinations and then analyzed by SPSS V.13. Duncan's new multiple-range test was used to determine the significant differences of means at the 5% level.
2.4. Conventional extraction
3. Results and discussion
Conventional extraction (CE) was carried out by the method of Corrales, Toepfl et al. (2008) with minor modification. The dried LFP powder (10 g) was extracted for 12 h using a magnetic stirrer with 500 mL of given solvents in a conical flask at 30 °C. The solvents were replaced periodically every 4 h. The extraction solution was filtered and the filtrate was collected and stored at 4 °C.
The factors concerning the HPE included solvent, solvent concentration, ratio of solid/liquid, pressure, time and temperature. The influence of each factor was analyzed by a single factor experiment.
2.5. Extraction yield The extraction yield was calculated by the method of Zhang, Bi, and Liu (2007). In brief, the obtained filtrate was evaporated to dryness by a rotary evaporator (RE-52A, Shanghai Woshi Co., Shanghai, China) under vacuum at 60 °C and then lyophilized in a freeze-dryer (Savant, Vapornet VN 100, Labequip Ltd., Cannada) to obtain a freeze-dried extract. The dried extract was weighed, and then the extraction yield was calculated and expressed as the percentage of the weight of the crude extract to the raw material (10 g).
3.1. The effects of different solvents on the extraction yield and total phenolic content Conventional extraction was carried out using four various types of solvents (ethyl-acetate, ethanol, methanol and water) to extract phenolic compounds from LFP. Fig. 1 shows that application of ethanol or methanol exhibited the highest total phenolic content, followed by water and ethyl acetate. Ethyl acetate is usually used for extraction of
2.6. Determination of total phenolic content Total phenolic content of each extract was determined using the standard gallic acid calibration curve by the method of Prasad, Divakar, Shivamurthy, and Aradhya (2005). Total phenolic content of each extract was expressed as mg/g on dry weight (DW) basis. 2.7. Determination of superoxide anion radical scavenging activity Superoxide anion radical scavenging activity was analyzed by the method of Duan, Wu, and Jiang (2007) with some modifications. All solutions were prepared in 0.2 M phosphate buffer (pH 7.4). Each extract at 50 or 100 μg/mL was mixed with 3 mL of reaction buffer
Fig. 1. The total phenolic content and extraction yield from longan fruit pericarp by conventional extraction for 12 h using various solvents and 1:50 (w/v) solid/liquid ratio at 30 °C. For each treatment means in a row followed by different letters were significantly different at the 5% level.
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flavonoid aglycones while ethanol, methanol and water are used for medium polar and polar compounds such as flavonoid glycoside, phenolic acids, polysaccharides and sugars depending upon their polarity (Jayaprakasha, Girennavar, & Patil, 2008). Because of difference in polarity of the extraction solvents, the solubility of phenolic compounds and the rate of mass transfer could be different (Bi, Zhang, Liu, & Wang, 2008). As flavonoids and phenolic acids are more soluble in methanol than ethanol, it is reasonable to obtain a higher extraction yield when methanol is used (Markham, 1982). Because ethanol is less toxic than methanol and easy for recycling, it was chosen for the subsequent experiments. 3.2. The effects of ethanol concentrations on the extraction yield and total phenolic content Ethanol at 25−100% (v/v) was used to extract phenolic compounds from LFP by CE. Generally, 40–50% ethanol has a greater effectiveness in extracting polyphenolic compounds compared to pure ethanol (Jayaprakasha et al., 2008). Total phenolic content and extraction yield from LFP was influenced greatly by ethanol concentrations (Fig. 2). When ethanol concentration increased from 25 to 50%, the increases in the phenolic content (14.2 ± 0.2 mg/g) and extraction yield (14.8 ± 0.6%) were observed, which was probably due to the increased solubility of flavonoids, phenolic compounds, hydrolysable tannins and polysaccharides in the mixture of ethanol and water. Spigno, Tramelli, and Faveri (2007) reported higher extraction yield and phenolic content from grape seeds when 50% ethanol was used. However, when ethanol concentration was higher than 75%, the extraction yield decreased. As the solvent may influence cellular structures (Zhang, Ruizhan, et al., 2007), 50% ethanol was used for the subsequent study. 3.3. The effects of solid to liquid ratio on the extraction yield and total phenolic content 50% ethanol was used to extract phenolic compounds from LFP by CE in this study. The total phenolic content and extraction yield increased with increasing solid to liquid ratio (m/v). When the solid to liquid ratio increased from 1:25 to 1:50, the total phenolic content and extraction yield increased from 12.1 ± 0.1 to 14.2 ± 0.2 mg/g DW and 13.5 ± 0.4 to 14.8 ± 0.6%, respectively (Fig. 3), which is probably due to the fact that more solvent can enter cells while more phenolic compounds can permeate into the solvent under the higher solid to liquid ratio condition (Zhang, Bi, et al., 2007). Kojic, Planinic, Tomas, Bilic, and Velie (2007) obtained higher polyphenol content from grape seeds when a solid to liquid ratio of 1:40 (m/v) was used. Although the solid to liquid ratio is useful for increasing the extraction yield, further
Fig. 2. The phenolic content and extraction yield from longan fruit pericarp by conventional extraction for 12 h using various ethanol concentrations and 1:50 (w/v) solid/liquid ratio at 30 °C. For each treatment means in a row followed by different letters were significantly different at the 5% level.
Fig. 3. The phenolic content and extraction yield from longan fruit pericarp by conventional extraction for 12 h using various solid/liquid (w/v) ratios using 50% ethanol at 30 °C. For each treatment means in a row followed by different letters were significantly different at the 5% level.
increase in the solid to liquid ratio did not improve greatly the total phenolic content. Therefore, the solid/liquid ratio of 1:50 (w/v) was used for the subsequent experiment. 3.4. The effects of high pressure on the extraction yield and total phenolic content 50% ethanol and a solid to liquid ratio of 1:50 (w/v) were used to extract phenolic compounds from LFP by HPE for 30 min. As shown in Fig. 4, the extraction yield and total phenolic content were greatly influenced by high pressure treatment. Compared to conventional extraction, the extraction yield increased from 14.8 ± 0.4 to 17.8 ± 0.4% when 500 MPa HPE was used. Also, the total phenolic content increased from 14.6 ± 0.2 to 21 ± 0.6 mg/g DW. High pressure treatment can increase the rate of mass transfer, enhance solvent penetration into the cells by disrupting the cellular walls and hydrophobic bonds in the cell membrane which may lead to a high permeability (BarbosaCanovas, Pothakamury, Palou, & Swanson, 1998; Dornenburg & Knorr, 1993; Oey, Lille, Loey, & Hendrickx, 2008). HPE can also cause deprotonation of charged groups, and distraction of salt bridges and hydrophobic bonds, resulting in conformational changes and denaturation of proteins and then rendering these phenolics compounds more available to extraction up to equilibrium (Barbosa-Canovas et al., 1998). Based on the phase behavior theory, the solubility of these compounds increased as the pressure increased (Richard, 1992). Thus, 500 MPa was used for the subsequent study.
Fig. 4. The phenolic content and extraction yield from longan fruit pericarp using conventional (control) and various high pressure extraction for 12 h and 30 min respectively, 50% ethanol and 1:50 (w/v) solid/liquid ratio at 30 °C. For each treatment means in a row followed by different letters were significantly different at the 5% level.
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K.N. Prasad et al. / Innovative Food Science and Emerging Technologies 10 (2009) 155–159 Table 1 A comparison of scavenging activities of superoxide anion radical and DPPH radical of HPE and CE extracts from longan fruit pericarp
CE extract HPE extract Ascorbic acid⁎ BHT⁎
Superoxide scavenging activity (%)
DPPH scavenging activity (%)
50 μg/mL
100 μg/mL
50 μg/mL
100 μg/mL
48.6 ± 2.9a 50.4 ± 0.9a 30.7 ± 2.7b 20 ± 3.5c
56.6 ± 2.3b 61.6 ± 1.1a 42 ± 2c 23 ± 1.7d
50.1 ± 0.2c 75 ± 0.2 b 80 ± 2 a 77.4 ± 2 a
76.6 ± 0.5b 77.7 ± 0.2a 80.4 ± 0.6a 80 ± 1a
Conventional extraction (CE): 50% ethanol, 1:50 (w/v) solid/liquid ratio and 12 h of extraction time at 30 °C and high pressure extraction (HPE): 50% ethanol, 1:50 (w/v) solid/liquid ratio, 500 MPa pressure and 2.5 min of extraction time at 30 °C. For each treatment means within a column followed by different letters were significantly different at the 5% level. ⁎Positive controls. Fig. 5. The phenolic content and extraction yield from longan fruit pericarp using various extraction time under 500 MPa, 50% ethanol and 1:50 (w/v) solid/liquid ratio at 30 °C. For each treatment means in a row followed by different letters were significantly different at the 5% level.
3.5. The effects of pressure holding time on the extraction yield and total phenolic content 50% ethanol, the solid to liquid ratio of 1:50 (w/v) and 500 MPa were used to examine the effects of various pressure holding time (2.5− 30 min) on phenolic compounds from LFP. Fig. 5 shows the effect of pressure holding time on the total phenolic content and extraction yield from LFP. The result indicated that the extraction yield and total phenolic content did not change significantly when extraction time increased from 2.5 to 30 min. According to the Pascal theory (Chen, Zhang, & Qian, 2005), the pressure transfers to the whole material uniformly and instantly during HPE process. Thus, the equilibrium of pressure between the inside and outside of the cells could occur in a very short time. Under these circumstances, the diffusion speed of the solvent is high while the extraction yield can reach the highest value very rapidly (Antonio & Gonzalo, 2005; Butz, Garcia, Lindauer, Dieterich, Bognar, & Tauscher, 2003). Similar results were reported by Zhang et al. (2005) and Prasad, Yang, Zhao, Wang, Chen, and Jiang (2008) to extract flavonoids from propolis and lychee, respectively. Therefore, an HPE time of 2.5 min was used for the following experiment. 3.6. The effects of high pressure temperature on the extraction yield and total phenolic content 50% ethanol, the solid to liquid ratio of 1:50 (w/v), 500 MPa and 2.5 min of extraction time was used to extract phenolic compounds
from LFP in this study. The extraction yield increased with increasing temperature (Fig. 6). When extraction temperature increased from 30 to 50 °C, the extraction yield increased from 17.6 ± 0.4 to 30 ± 0.8%. Similarly, the total phenolic content also increased from 21 ± 0.6 to 23 ± 0.3 mg/g DW. A rise in extraction temperature can break the phenolicmatrix bonds and influence the membrane structure of plant cells making them less selective by coagulation of lipoproteins (Fernandez, Goodwin, Lemmon, Levelt-sengers, & Williams, 1997). The dielectric constant of water decreases and solvent property and capacity change at higher temperature, resulting in a better extraction of phenolics (Corrales, Garcia, Butz, & Tauscher, 2008). However, further increase in extraction temperature could degrade phenolic compounds (Durling et al., 2007). 3.7. Comparison of HPE and CE In association with the further effectiveness in evaluating these extraction methods, the antioxidant activity was analysed (Table 1). The antioxidant activity of the samples obtained by HPE was higher than CE in the two system tested. The highest scavenging activity of superoxide anion radical was obtained for HPE (61.6 ± 1.1) while the lowest activity (23 ± 1.7) was observed for BHT as a concentration of 100 μl/mL was used. Similarly, the DPPH scavenging activity of HPE extract at 50 μg/mL was 75 ± 0.2%, which was comparable to BHT, whereas CE extract was only 50.1 ± 0.2%. The antioxidant activity of HPE or CE extract is in accordance with the amount of phenolic compounds. The phenolic compounds exhibit extensive free radical scavenging activities through their reactivity as hydrogen or electron-donating agents, and metal ion chelating properties (Rice-Evans, Miller, & Paganga, 1996). LFP contains a high amount of polar compounds like phenolic acids, flavonoids and polysaccharides which are good antioxidant compounds (Soong & Barlow, 2006; Rangkadilok et al., 2007). Using high pressure treatment, these compounds can be extracted efficiently due to increase in solvent power, solvent density and solubility of polar compounds. In addition, high pressure processing can cause enhancement of chemical and biochemical reactions in the cells by both desired and undesired modification (Oey et al., 2008). Moreover, high pressure treatment provides the possibility of inactivating degrading enzymes which may account for higher extraction yield and antioxidant activity compared to other methods. 4. Conclusions
Fig. 6. The phenolic content and extraction yield from longan fruit pericarp using various extraction temperatures under 500 MPa, 2.5 min, 50% ethanol and 1:50 (w/v) solid/liquid ratio. For each treatment means in a row followed by different letters were significantly different at the 5% level.
Conditions for HPE on extraction yield from LFP were investigated. Compared with the conventional extraction method, HPE provided higher extraction yield and required less extraction time. The higher total phenolic content and the stronger antioxidant activity of LFP by HPE were also obtained as compared with the conventional extraction. Thus, HPE could be an alternative method for extracting bioactive compounds from LFP to the conventional extraction. Further investigation of
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a comparison of the operation cost between HPE and CE can be needed for commercial usage. Acknowledgements This work was supported by the National Natural Science Foundation of China (Grant Nos. 30425040 and 30700557). References Ahmed, J., & Ramaswamy, H. S. (2006). High pressure processing of fruits and vegetables. Stewart Postharvest Review, 1, 1−10. Antonio, T. J., & Gonzalo, V. G. (2005). Commercial opportunities and research challenges in the high pressure processing of foods. Journal of Food Engineering, 67, 95−112. Barbosa-Canovas, G.V., Pothakamury, U.R., Palou, E., & Swanson, B.G. (1998). Nonthermal preservation of foods (pp. 9–52, 139–213), New York: Marcel Dekker. Bi, H. M., Zhang, S., Liu, C., & Wang, C. Z. (2008). High hydrostatic pressure extraction of salidroside from Rhodiola Sachalinensis. Journal of Food Process Engineering. doi:10.1111/j.1745-4530.2007.00202 Bravo, I. (1998). Polyphenols: chemistry, dietary sources, metabolism, and nutritional significance. Nutrition Reviews, 56, 317−333. Butz, P., Garcia, A. F., Lindauer, R., Dieterich, S., Bognar, A., & Tauscher, B. (2003). Influence of ultra high pressure processing on fruit and vegetable products. Journal of Food Engineering, 56, 233−236. Chen, E. S., Zhang, X., & Qian, X. M. (2005). Food ultrahigh pressure process technology (pp. 2−3). Beijing: Chemical Industry Publishing House. Corrales, M., Garcia, A. F., Butz, P., & Tauscher, B. (2008). Extraction of anthocyanins from grape skin assisted by high hydrostatic pressure. Journal of Food Engineering, 90(4), 415−421. doi:10.1016/j.jfoodeng Corrales, M., Toepfl, S., Butz, P., Knorr, D., & Tauscher, B. (2008). Extraction of anthocyanins from grape by-products assisted by ultrasonic, high hydrostatic pressure or pulsed electric fields: a comparison. Innovative Food Science and Emerging Technologies, 9, 85−91. Dornenburg, H., & Knorr, D. (1993). Cellular permeabilization of cultured plant tissues by high electric field pulses or ultra high pressure for the recovery of secondary metabolites. Food Biotechnology, 7, 35−48. Duan, X., Wu, G., & Jiang, Y. (2007). Evaluation of antioxidant properties of phenolics from litchi fruit in relation to pericarp browning prevention. Molecules, 12, 759−771. Durling, N. E., Catchpole, O. J., Grey, J. B., Webby, R. F., Mitchell, K. A., Foo, L. Y., & Perry, N. B. (2007). Extraction of phenolics and essential oil from dried sage (Salvia officianlis) using ethanol-water mixtures. Food Chemistry, 101, 1417−1424. Fernandez, D. P., Goodwin, A. R. H., Lemmon, E. W., Levelt-sengers, J. M. H., & Williams, R. C. (1997). A formulation for the static permitivity of water and steam at temperature from 238 K to 873 K at pressures up to 1200 MPa, including derivatives and Deby–Hückel coefficients. Journal of Physical Chemistry, 26, 1125−1166. Jayaprakasha, G. K., Girennavar, B., & Patil, B. S. (2008). Radical scavenging activities of Rio Red grapefruits and sour orange fruit extracts in different in vitro model systems. Bioresource Technology, 99, 4484−4494. Kojic, A. B., Planinic, M., Tomas, S., Bilic, M., & Velie, D. (2007). Study of solid–liquid extraction kinetics of total polyphenols from grape seeds. Journal of Food Engineering, 81, 236−242.
159
Namiki, M. (1990). Antioxidants/antimutagens in foods. Critical Review in Food Science and Nutrition, 29, 273−300. Markham, K. R. (1982). Techniques of flavonoid identification. London: Academic Press. Moon, J. H., & Terao, J. (1998). Antioxidant activity of caffeic acid and dihydrocaffeic acid in lard and human low-density lipoprotein. Journal of Agricultural and Food Chemistry, 46, 5062−5065. Oey, I., Lille, M., Loey, A. V., & Hendrickx, M. (2008). Effect of high pressure processing on colour, texture and flavour of fruit and vegetable-based food products: a review. Trends in Food Science and. Technology, 19, 320−328. Pan, Y., Wang, K., Huang, S., Wang, H., Mu, X., He, C., Ji, X., Zhang, J., & Huang, F. (2008). Antioxidant activity of microwave-assisted extract of longan (Dimocarpus longan Lour.) peel. Food Chemistry, 106, 1264−1270. Prasad, N. K., Divakar, S., Shivamurthy, G. R., & Aradhya, S. M. (2005). Isolation of a free radical scavenging antioxidant from water spinach (Ipomoea aquatica Forsk). Journal of the Science of Food and Agriculture, 85, 1461−1468. Prasad, N. K., Yang, B., Zhao, M., Wang, B., Chen, F., & Jiang, Y. (2008). Effects of high pressure treatment on the extraction yield, phenolic content and antioxidant activity of litchi (Litchi chinensis Sonn.) fruit pericarp. International Journal of Food Science and. Technology. doi:10.1111/j.1365-2621.2008.01768.x Rangkadilok, N., Sitthimonchai, S., Worasuttayangkurn, L., Mahidol, C., Ruchirawat, M., & Satayavivad, J. (2007). Evaluation of free radical scavenging and antityrosinase activities of standardized longan fruit extract. Food and Chemical Toxicology, 45, 328−336. Rangkadilok, N., Worasuttayangkurn, L., Bennett, R. N., & Satayavivad, J. (2005). Identification and quantification of polyphenolic compounds in longan (Euphoria longana Lam.) fruit. Journal of Agricultural and Food Chemistry, 53, 1387−1392. Rice-Evans, C. A., Miller, N. J., & Paganga, G. (1996). Structure antioxidant activity relationship of flavonoids and phenolic acids. Free Radical Biololgy & Medicine, 20, 933−956. Richard, J. S. (1992). High pressure phase behavior of multi component fluid mixtures. Amsterdam: Elsevier. Soong, Y. Y., & Barlow, P. J. (2006). Quantification of gallic acid and ellagic acid from longan (Dimocarpus longan Lour.) seed and mango (Mangifera indica L.) kernal and their effects on antioxidant activity. Food Chemistry, 97, 524−530. Spigno, G., Tramelli, L., & Faveri, D. M. D. (2007). Effects of extraction time, temperature and solvent on the concentration and antioxidant activity of grape marc phenolics. Journal of Food Engineering, 81, 200−208. Yang, B., Zhao, M., Shi, J., Yang, E., & Jiang, Y. (2008). Effect of ultrasonic treatment on the recovery and DPPH radical scavenging activity of polysaccharides from longan fruit pericarp. Food Chemistry, 106, 685−690. Zhang, S., Junjie, Z., & Changzhen, W. (2004). Novel high pressure extraction technology. International Journal of Pharmaceutics, 78, 471−474. Zhang, S., Xi, J., & Wang, C. Z. (2005). Effect of high hydrostatic pressure on extraction of flavonoids in propolis. Food Science and Technology International, 11, 213−216. Zhang, Z. M., & Li, L. (2007). A preliminary study of plant aroma profile characteristics by a combination sampling method coupled with GC-MS. Microchemical Journal, 86, 29−36. Zhang, S., Bi, H., & Liu, C. (2007). Extraction of bio-active components from Rhodiola sachalinensis under ultrahigh hydrostatic pressure. Separation and Purification Technology, 57, 275−280. Zhang, S., Ruizhan, C., & Changzheng, W. (2007). Experiment study on ultrahigh pressure extraction of ginsenosides. Journal of Food Engineering, 79, 1−5.