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Total phenolics, carotenoids and antioxidant properties of Tommy Atkin mango cubes as affected by drying techniques
LWT - Food Science and Technology xxx (2014) 1e5
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Research note
Total phenolics, carotenoids and antioxidant properties of Tommy Atkin mango cubes as affected by drying techniques Dalbir Singh Sogi a, b, *, Muhammad Siddiq a, c, Kirk D. Dolan a, d a
Department of Food Science and Human Nutrition, Michigan State University, East Lansing MI 48824, USA Department of Food Science and Technology, Guru Nanak Dev University, Amritsar 143 005, India c Food Science Consultant, Windsor, Canada d Department of Biosystems & Agricultural Engineering, Michigan State University, East Lansing, MI 48824, USA b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 26 June 2013 Received in revised form 22 January 2014 Accepted 4 April 2014 Available online xxx
Mango (Mangifera indica L) cubes were dehydrated using different techniques; lyophilization or freezedrying, cabinet (hot-air), vacuum and Infra-red (FD, CD, VD, IRD, respectively). Total phenolics, carotenoids, ascorbic acid contents and antioxidant properties (ABTS, DPPH, FRAP, ORAC) of mango powder were determined. Mango powder contained high quantity of phenolics (936.2e1725.2 mg GAE/100 g db, with highest in FD and lowest in CD samples), ascorbic acid (97e225 mg/100 g db, highest in FD and lowest in IRD samples) and total carotenoids (3.3e5.2 mg/100 g db). Freezeedried powder had the highest antioxidant properties than those from other drying techniques. ORAC values varied from 408 to 651 m mol TE/100 g db. Solubility of cabinet-dried powder was the highest. Water and oil Absorption Index ranged between 2.54e2.87 and 1.69e2.75, respectively. Freeze dried powders had the lower bulk density than samples from other drying techniques. Physicochemical characteristics of the freeze- and cabinet-dried mango powders offer potential application in food products. Ó 2014 Published by Elsevier Ltd.
Keywords: Mango Drying Powder Antioxidant properties Carotenoids
1. Introduction Mango (Mangifera indica L.) is a widely consumed tropical fruit in fresh or processed form throughout the world. This fruit has limited storage life since it cannot be stored at low temperatures because of its susceptibility to chilling injury. Moreover, mangoes need to be treated with hot water as quarantine requirement which accelerates the ripening process (Kim, Lounds-Singleton, & Talcott, 2009). These limitations lead to substantial postharvest losses creating massive quantity of culled fruit as bio-waste, which offers a potential to be developed into value-added products. Polyphenols, carotenoids, and vitamins impart healthpromoting properties to mango due to their antioxidant activities (Dorta, Lobo, & González, 2012a; Siddiq, Sogi, & Dolan, 2013; Sogi, Siddiq, Roidoung, & Dolan, 2012) and the fiber content of mango offers potential for its use in bakery products (Vergara-Valencia et al., 2007). Since mangoes are susceptible to decomposition because of their high water content and nutrients, drying can
* Corresponding author. Department of Food Science and Technology, Guru Nanak Dev University, Amritsar 143 005, India. Tel.: þ91 183 2258802x3217; fax: þ91 183 2258820. E-mail addresses: [email protected], [email protected] (D.S. Sogi).
effectively preserve this fruit while offering expanded usage in different food products. The method of drying can have a negative impact on quality; for example, hot air drying was shown to have negative effect on the antioxidant properties of mango (Dorta, Lobo, & Gonzalez, 2012b). Currently, mango slices are dried by dipping in sugar for marketing as a snack product; however, presently, dried mangoes for use in various food applications are not available commercially. The objective of this study was to evaluate different methods for drying mango and evaluate the antioxidant and functional properties of dried mangoes powders. 2. Materials and methods 2.1. Materials Market-ripe Tommy Atkin mangoes with green-purple peel, firm texture and light yellow flesh were procured from a local source. Fruits were sorted, washed, and sanitized (5-min dip in Fruit & Vegetable Wash at 3.75 g/L water; SC Johnson Professional, Sturtevant, WI, USA). Mangoes were peeled/diced manually using stainless steel knives to get w10 mm cubes. All chemicals used in this study were of analytical grade and were purchased from SigmaeAldrich (St Louis, MO, USA) and W.W.
http://dx.doi.org/10.1016/j.lwt.2014.04.015 0023-6438/Ó 2014 Published by Elsevier Ltd.
Please cite this article in press as: Sogi, D. S., et al., Total phenolics, carotenoids and antioxidant properties of Tommy Atkin mango cubes as affected by drying techniques, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.04.015
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D.S. Sogi et al. / LWT - Food Science and Technology xxx (2014) 1e5
Grianger, Inc. (Lake Forest, IL, USA). Unless noted otherwise, all extractions/dilutions were made using 80:20 methanolewater (methanol-80). 2.2. Drying of mango cubes Four drying techniques were employed: 1) Freeze drying (FD) e Samples were frozen at 20 C and dried in a pilot-scale lyophilizer (Vertis Company Inc., Gardiner, NY, USA) with the condenser temperature and chamber vacuum at 55 C and 4 Pa respectively; 2) Hot-air/Cabinet dying (CD) e samples were dried in a cabinet dryer (Proctor and Schwartz Inc., Philadelphia, PA, USA) operated at 60 2 C with constant air circulation; 3) Vacuum drying (VD)e Samples were kept in a vacuum oven (Sheldon Manufacturing Inc., Cornelius, OR, USA) set at 60 2 C and vacuum was maintained at 66.7 kilo-Pascal; 4) Infra-red drying (IRD) e The mango cubes were dried in a custom-made IR heating unit consisting of aluminum housing, with two 40-Watt IR bulbs. The drying was terminated based on the appearance of dehydrated mango cubes. The dried mango cubes were ground using a coffee grinder to pass through US40 Sieve (0.5 mm), packaged in polyethylene bags and stored at 20 C until analyzed. The mango powders were used for analyzing antioxidant, physicoechemical and functional properties. 2.3. Total phenolics, ascorbic acid and carotenoids analysis Total phenolics, as gallic acid equivalent (GAE), were determined according to Singleton and Rossi (1965). Briefly, 1 g samples were mixed with 20 mL of methanol-80, agitated on water-bath shaker for 1 h, followed by centrifugation (10,000 g for 10 min). Supernatants were collected and residues were re-extracted twice using 10 mL of methanol-80 by 1-min vortexing and centrifugation (10,000 g for 5 min). Mango powders were extracted and titrated against indophenol dye (2, 6 dichloro indophenol, sodium salt) to determine ascorbic acid content (AOAC, 1991). For total carotenoids, samples were extracted with hexane:acetone (7:3) solution and after phase transfer the absorbance was read at 450 nm using a spectrophotometer (Milton Roy, Pennsylvania, USA) following Davis, Collins, Fish, Tadmor, Webber, & Perkins-Veazie (2007). Total carotenoids were determined as b-carotene equivalent using a standard curve prepared with pure b-carotene (0.5e2.5 mg/mL). 2.4. Antioxidant properties Sample extraction protocol for antioxidant analysis was the same as for total phenolics. The antioxidant capacities were expressed as m mol trolox equivalent (TE)/g db. 2.4.1. ABTS assay The ABTS (2,20 -Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) antioxidant activity was determined using ABTSþ radical cation decolorization assay (Re et al., 1999), with little modification. Briefly, 7 mmol/L ABTS solution and 2.45 mmol/ L potassium persulfate were mixed in 1:1 ratio and allowed to stand in the dark for 12e16 h to produce ABTS radical cation (ABTSþ) stock solution. The ABTSþ working solution (3 mL) and 30 mL of blank, standard or sample were mixed and the absorbance was measured at 734 nm after 6 min using a spectrophotometer. The blank was run with methanol-80 and standard curve was prepared using 0.3e1.5 mmol Trolox/L. 2.4.2. DPPH assay Radical scavenging activity of mango powders was determined following Brand-Williams, Cuvelier, and Berset (1995).
Briefly, one part of stock solution of 2,2-Diphenyl-1picrylhydrazyl or DPPH (0.24 g/100 mL methanol) was diluted with ten parts methanol-80 to get working solution having absorbance of 1.1 0.02 at 515 nm. Blank, standard or samples (0.6 mL) and 3.0 mL of DPPH working solution were mixed, kept in dark for 20 min and absorbance was recorded at 515 nm. Standard curve was prepared to calculate DPPH activity using 50e250 mmol Trolox/L. 2.4.3. Ferrric reducing antioxidant power (FRAP) assay The ferric reducing ability of dried mango powders was measured following Benzie and Strain (1996). The stock solutions 300 mmol/L acetate buffer, 10 mmol/L 2,4,6-Tris(2-pyridyl)-striazine (TPTZ) solution in 40 mmol/L HCl, and 20 mmol/L FeCl3$6H2O solution were prepared. The fresh working solution was prepared by mixing acetate buffer, TPTZ solution, and ferric chloride solution in 10:1:1 ratio respectively. Blank, standard or samples (0.3 mL) were mixed with 3 mL working solution and absorbance was read after 5 min at 595 nm. Methanol-80 and Trolox (50e250 mmol/L) were used for blank and standard curve respectively. 2.4.4. Oxygen radical absorbance capacity (ORAC) assay The analysis was carried out following Huang, Ou, HampschWoodill, Flanagan, and Prior (2002). Briefly, 150 mL of fluorescein (20 nmol/L) was added to the designated wells of a 96-wells black plate, followed by the addition of 25 mL of blank, standard (Trolox 25e100 mmol/L) or samples to the designated wells. The plate was incubated at 37 C for 30 min in Microplate Reader (Biotek Instruments, Winooski, VT, USA). Then, 25 mL of freshly prepared 2, 20 Azobis (2-methylpropionamidine) dihydrochloride (153 mmol/L) was added to all the designated wells. Fluorescence was monitored using 485 nm excitation and 528 nm emissions at 2 min intervals for 180 min. 2.5. Physicoechemical analysis and functional properties Dehydrated samples (w2.5 g) were analyzed for moisture content using IR moisture meter (Denver Instrument, Bohemia, NY, USA). Titratable acidity of dehydrated mango was determined by taking 0.5 g of sample in 20 mL distilled water, adding two drops of phenolphthalein and titrating against standardized 0.1 mol/L NaOH solution. The pH was measured by taking 0.5 g sample in 50 mL distilled water using Oakton pH meter (Eutech Instruments, Singapore). Loose and packed bulk density of the mango powder was determined by transferring 10 g mango powder to a 250 mL measuring cylinder and measuring its loose and packed volume (CRA, 1998). Solubility of mango powder was determined using the method of (Cano-Chauca, Stringheta, Ramos, & Cal-Vidal, 2005) by dispersing 1 g mango powder in 100 mL water, blending, centrifuging (3000 g, 5 min) and drying supernatant at 105 C for 5 h). The water/oil absorption indices (WAI/OAI) were determined using methods described by Beuchat (1977) by mixing 1 g of sample with 10 mL of distilled water or oil for 30 s, standing for 30 min, centrifugation at 5000 g for 30 min, draining and measuring gain in weight. 2.6. Statistical analysis All the experiments were done using three replicates and data reported as mean standard deviation. Data were analyzed using JMP 9.0 software (SAS Institute, Inc., Cary, North Carolina, USA). The significant difference comparisons were made by Tukey’s HSD test (p 0.05).
Please cite this article in press as: Sogi, D. S., et al., Total phenolics, carotenoids and antioxidant properties of Tommy Atkin mango cubes as affected by drying techniques, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.04.015
D.S. Sogi et al. / LWT - Food Science and Technology xxx (2014) 1e5
3. Results and discussion 3.1. Total phenolics, ascorbic acid and carotenoids 3.1.1. Total phenolics Drying methods affected phenolics content, ranging from 963.2 mg GAE/100 g db in VD samples to 1725.2 GAE/100 g db in FD samples (Fig. 1a). The highest content observed in FD samples might be due to no heat used in this method. Statistical analysis revealed that CD and VD samples contained significantly (p 0.05) lower phenolic content as compared to FD and IRD. Ice crystals,
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formed within the tissue matrix during freeze drying, rupture the cell structure facilitating solvent extraction and consequently high extraction of phenolic compounds (Shih, Kuo, & Chiang, 2009). Infrared dried sample had high phenolic content which might be due to non-enzymatic conversion of phenolic precursors to new phenolic compounds as in case of microwave drying (Soong & Barlow, 2004). Total phenolic content of freeze dried powder from Tommy Atkins mangoes has been reported to be 825 mg GAE/ 100 g (Hung, 2012). Our results showed higher values of phenolic content of mango powder than reported by these researchers, which might be attributed differences in fruit maturity or horticultural practices. 3.1.2. Ascorbic acid Dried mango powders contained ascorbic acid varying from 97.59 to 225.38 mg/100 g db (Fig. 1b). Ascorbic content of powders exhibited the negative effect of heat damage. Statistical analysis indicated significantly lower ascorbic acid content in powders of CD, VD and IRD involving heat during drying (p 0.05). Ndawula, Kabasa, and Byaruhanga (2004) reported that ascorbic acid content of ripe mango fruit was 164.3 mg/100 g db, which reduced to 25.4e68.5 mg/100 g db on drying. The ascorbic acid values obtained in present study were in close agreement to those reported previously. 3.1.3. Carotenoids The total carotenoids content was 3.28 and 5.17 mg/100 g db in IRD and FD samples, respectively (Fig. 1c). Drying showed a significant effect of heat on total carotenoids with the highest levels in lyophilized samples (p 0.05). Ndawula et al. (2004) reported bcarotene contents of mango to be 5.9 mg/100 g db, which were degraded on drying to 0.34e1.58 mg/100 g db level. The carotenoids content values were within the range of previously reported and supported the declining trends in values with driers operating at higher temperature. 3.2. Antioxidant properties 3.2.1. ABTS method Antioxidant properties of the dried mango samples varied from 50.7 to 103.8 m mol TE/g db (Fig. 2a). There was significant decrease in antioxidant properties of mango powder with drying technique involving heat during drying (p 0.05). Hung (2012) reported ABTS scavenging activities of dehydrated mango varying from 46.7 to 73.8 m mol TE/g db. Antioxidant activity of dried mango flesh was 27.1 m mol/g db ascorbic acid equivalent using ABTS assay (Soong & Barlow, 2004). The values obtained for antioxidant capacity as Trolox equivalent are within the close range of previously reported results. 3.2.2. DPPH method The DPPH antioxidant values varied from 34 to 88.6 m mol TE/ g db in dehydrated mango powder. The antioxidant capacity significantly changed with the drying techniques employed (p 0.05). DPPH values in green and ripe pulp of mango were 12.2 and 9.8 m mol TE/g db, respectively (Aziz, Wong, Bhat, & Cheng, 2012). The DPPH radical scavenging activity varied from 36.5 to 52.0 m mol TE/g db in dried Tommy Atkin mango flesh (Hung, 2012). The previously reported values support the present data for Tommy Atkin mango.
Fig. 1. Effect of different drying methods on total phenolics, ascorbic acid, and total carotenoids content of dried mango powder (FD e Freeze drying; CD e Cabinet drying; VD e Vacuum drying; IRD e Infrared drying).
3.2.3. FRAP method The values obtained by FRAP assay were lower than those obtained by ABTS or DPPH methods but the pattern was similar (Fig. 2c). FRAP values varied from 41 to 81 m mol TE/g db for the
Please cite this article in press as: Sogi, D. S., et al., Total phenolics, carotenoids and antioxidant properties of Tommy Atkin mango cubes as affected by drying techniques, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.04.015
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Fig. 2. Effect of drying techniques on the antioxidant properties (a) ABTS, (b) DPPH, (c) FRAP, (d) ORAC, of dried mango powder (FD e Freeze drying; CD e Cabinet drying; VD e Vacuum drying; IRD e Infrared drying).
dried mango powder. Drying techniques were shown to have a significant impact on FRAP values of powders (p 0.05). Soong and Barlow (2004) reported mango cubes had antioxidant activity of 36.6 m mol/g db, ascorbic acid equivalent, using FRAP assay. Mango pulp from green and ripe fruit showed FRAP value of 16.42 and 15.30 m mol TE/g db, respectively (Aziz et al. 2012). Our data on antioxidant activity for mango powder were comparable to those reported previously. 3.2.4. ORAC method The antioxidant activity measured by ORAC for dried powders from different drying methods was 408e651 m mol TE/g db (Fig. 2d). Statistical analysis indicated significant change in ORAC values of powders with different dryers used (p 0.05), however, FD and IRD samples values did not vary significantly. Hung (2012) reported that hydrophilic ORAC values varied from 32 to 62.1 m mol TE/g db whereas lipophilic ORAC values varied from 1.2 to 2.5 m mol TE/g db in dehydrated mango flesh using sun, air, freeze, vacuum and microwave techniques. The ORAC value obtained in present study are higher than reported values in literature which might be due to variability in material used.
3.3. Physicoechemical analysis 3.3.1. Moisture content, pH, titratable acidity and solubility Dehydrated mango powders were analyzed for selected physicochemical properties that are important for handling and utilization of dried ingredients. 3.3.1.1. Moisture content. The initial moisture content of raw mango cubes was 86.85 g/100 g. The final moisture content varied from 5.86 to 10.61 g/100 g on wet basis after dehydration (Table 1). The variation in the final moisture was statistically significant (p 0.05), which was due to the subjective method used to terminate drying process based on appearance of the product. The results are therefore given on the dry basis (db) to offset any variations due to moisture content. The initial moisture content values reported in the literature were lower than those observed in the present study which might be due to the variation in fruit maturity and method of analysis employed. 3.3.1.2. pH and titratable acidity. It is an important parameter for blending with pH sensitive food like milk and other dairy products.
Table 1 Effect of drying techniques on the physicoechemical properties of mango powder. Parameters Moisture (g/100 g wb) PH Titratable acidity (g/100 g db) Solubility (g/100 g db) Water Absorption Index, WAI (g/g db) Oil Absorption Index, OAI (g/g db) Bulk density, loose (g/mL wb) Bulk density, packed (g/mL wb)
FD 9.83 3.65 7.86 77.60 2.76 2.75 0.17 0.39
CD
bc
0.22 0.03bc 0.57a 1.69a 0.16ab 0.19a 0.02c 0.05c
7.24 3.72 6.74 78.69 2.87 1.93 0.44 0.63
VD
ab
1.77 0.04b 0.41ab 0.34a 0.17ab 0.07b 0.01b 0.02ab
5.86 3.83 6.22 74.17 2.54 1.69 0.54 0.69
IRD
a
0.74 0.02a 0.52b 1.00a 0.07b 0.18b 0.06a 0.03a
10.61 3.63 7.52 66.80 3.14 1.95 0.41 0.57
0.48c 0.03c 0.55ab 5.09b 0.29a 0.15b 0.08b 0.05b
FD e Freeze drying; CD e Cabinet drying; VD e Vacuum drying; IRD - Infrared drying. Values are given as Mean SD. Means sharing different letters in rows are significantly different from each other (p 0.05). wb e wet weight basis; db e dry weight basis.
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The pH of powders was in the range of 3.63e3.72 (Table 1) and varied significantly due to drying method used (p 0.05). The titrable acidity as anhydrous citric acid equivalents in powder ranged from 6.22 to 7.86 g/100 g db (Table 1). The acidity decreased in heated samples during drying as compared to lyophilized sample. The heat might induce Maillard’s reaction involving acid and proteins resulting in slight decrease in acidity. Statistical analysis revealed that VD mango powder had significantly lower acidity values than freeze dried samples. 3.3.1.3. Solubility. Results indicated solubility values of 67e79 g/ 100 g db in mango powders due to the presence of sugars and other soluble matters. Statistical analysis indicated significant change in solubility with types of drying techniques used (p 0.05). Solubility of mango powder was observed to be 89.70, 94.38, 95.31 and 90.79 g/100 g in freeze, drum, spray and refractive window dried samples, respectively (Caparino et al., 2012). The solubility values observed in the present study were lower than those reported in the literature previously, which might be due to different ripening stage and cultivar type since Caparino et al. (2012) used 95e100% ripe mangoes of ‘Carabo’ cultivar whereas in current study slightly ripe ‘Tommy Atkin’ mangoes were used. 3.3.2. Water/oil absorption index (WAI, OAI) The WAI shows the amount of the water uptake by per unit mass of dried powder. The WAI of dried mango powder was 2.54e3.14 g/ g db (Table 1). Statistical analysis revealed WAI varied significantly with types of drying systems in three samples (p 0.05). Present results revealed lower WAI values for mango powder as compared to those reported previously. Statistical analysis revealed that OAI of dried powders (1.69e2.75 g/g db) differed significantly with the drying method used. 3.3.3. Bulk density The loose and packed bulk density values were lower for FD mango powder (0.17 and 0.39 g/mL, respectively) indicating a fluffy product (Table 1). Other drying techniques yielded products with higher bulk density values, which might be due to excessive shrinkage during dying. The packed and loose bulk density can be correlated with the solubility indicating lower density products were more soluble. Bulk density of mango powder was observed to be 0.44, 0.76, 0.46 and 0.68 g/mL in freeze, drum, spray and refractive window dried samples, respectively (Caparino et al., 2012). Bulk density of green and ripe mango pulp dehydrated in hot air dryer was 0.69 and 0.68 g/g db respectively (Aziz et al., 2012). The values of bulk densities in present investigation were comparable with those reported in the literature. 4. Conclusion Mango cubes can be preserved by dehydration for use in different food applications. Total phenolics, ascorbic acid, carotenoids and antioxidant properties of dehydrated powders were lower in hot air, vacuum and IR drying technique involving heat compared to freeze drying. Solubility, water and oil absorption values of dried mango powders were adequate for their utilization. The dehydrated mango can be utilized for enhancing flavor and added fiber and antioxidant-rich phytochemicals for preparing healthy and nutritious food products, especially snacks.
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Acknowledgment Authors thank the U.S. Fulbright Program for Dalbir S. Sogi’s Research Fellowship and Project GREEEN at Michigan State University for partial financial support of this research. References AOAC. (1991). Association of official analytical chemists. Washington, DC. Aziz, N. A. A., Wong, L. M., Bhat, R., & Cheng, L. H. (2012). Evaluation of processed green and ripe mango peel and pulp flours (Mangifera indica var Chokanan) in term of chemical composition, antioxidant compounds and functional properties. Journal of Science of Food & Agriculture, 92, 557e563. Benzie, I. F. F., & Strain, J. J. (1996). The ferric reducing ability of plasma (FRAP) as a measure of “antioxidant” power: the FRAP assay. Analytical Biochemistry, 239, 70e76. Beuchat, L. R. (1977). Functional and electrophoretic characteristics of succinylated peanut flour protein. Journal of Agriculture & Food Chemistry, 25, 258e 261. Brand-Williams, W., Cuvelier, M. E., & Berset, C. (1995). Use of a free radical method to evaluate antioxidant activity. LebensmitteleWissenschaft und Technologie, 28, 25e30. Cano-Chauca, M., Stringheta, P. C., Ramos, A. M., & Cal-Vidal, J. (2005). Effect of the carriers on the microstructure of mango powder obtained by spray drying and its functional characterization. Innovative Food Science & Emerging Technologies, 5, 420e428. Caparino, O. A., Tang, J., Nindo, C. I., Sablani, S. S., Powers, J. R., & Fellman, J. K. (2012). Effect of drying methods on the physical properties and microstructures of mango (Philippine ‘Carabao’ var.) powder. Journal of Food Engineering, 111, 135e 148. CRA. (1998). Bulk density (B-16). Analytical methods. Washington, DC, USA: Corn Refiners Association, Inc. Davis, A. R., Collins, J., Fish, W. W., Tadmor, Y., Webber, C. L., & Perkins-Veazie, P. (2007). Rapid method for total carotenoid detection in canary yellow-fleshed watermelon. Journal of Food Science, 72, S319eS323. Dorta, E., Lobo, M. G., & González, M. (2012a). Using drying treatments to stabilise mango peel and seed: effect on antioxidant activity. LWT e Food Science & Technology, 45, 261e268. Dorta, E., Lobo, M. G., & Gonzalez, M. (2012b). Reutilization of mango byproducts: study of the effect of extraction solvent and temperature on their antioxidant properties. Journal of Food Science, 71, 80e88. Huang, D. J., Ou, B. X., Hampsch-Woodill, M., Flanagan, J. A., & Prior, R. L. (2002). High-throughput assay of oxygen radical absorbance capacity (ORAC) using a multichannel liquid handling system coupled with a microplate fluorescence reader in 96-well format. Journal of Agriculture & Food Chemistry, 50, 4437e 4444. Hung, L. M. (2012). Antioxidative effects of mango wastes on shelf life of pork products. PhD thesis. New Zealand: Lincoln University. Kim, Y., Lounds-Singleton, A. J., & Talcott, S. T. (2009). Antioxidant phytochemical and quality changesassociated with hot water immersion treatment of mangoes (Mangifera indica L.). Food Chemistry, 115, 989e993. Ndawula, J., Kabasa, J. D., & Byaruhanga, Y. B. (2004). Alterations in fruit and vegetable b-carotene and vitamin C content caused by open-sun drying, visqueen-covered and polyethylene-covered solar-dryers. African Health Sciences, 4(2), 125e130. Re, R., Pellegrini, N., Proteggente, A., Pannala, A., Yang, M., & Rice-Evans, C. (1999). Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free Radical Biology & Medicine, 26, 1231e1237. Shih, M. C., Kuo, C. C., & Chiang, W. (2009). Effects of drying and extrusion on colour, chemical composition, antioxidant activities and mitogenic response of spleen lymphocytes of sweet potatoes. Food Chemistry, 117(1), 114e121. Siddiq, M., Sogi, D. S., & Dolan, K. (2013). Antioxidant properties, total phenolics, and quality of fresh-cut ‘Tommy Atkins’ mangoes as affected by different pretreatments. LWT-Food Science & Technology, 53, 156e162. Singleton, V. L., & Rossi, J. A. (1965). Colorimetry of total phenolics with phosphomolybdic-phosphotungstic acid reagents. American Journal of Enology and Viticulture, 16, 144e158. Sogi, D. S., Siddiq, M., Roidoung, S., & Dolan, K. D. (2012). Total phenolics, carotenoids, ascorbic acid and antioxidant properties of fresh-cut mango (Mangifera indica L., cv. Tommy Atkin) as affected by infra-red heat treatment. Journal of Food Science, 77, C1197eC1202. Soong, Y. Y., & Barlow, P. J. (2004). Antioxidant activity and phenolic content of selected fruit seeds. Food Chemistry, 88, 411e417. Vergara-Valencia, N., Granados-Pérez, E., Agama-Acevedo, E., Tovar, J., Ruales, J., & Bello-Pérez, L. A. (2007). Fibre concentrate from mango fruit: characterization, associated antioxidant capacity and application as a bakery product ingredient. LWT e Food Science & Technology, 40, 722e729.
Please cite this article in press as: Sogi, D. S., et al., Total phenolics, carotenoids and antioxidant properties of Tommy Atkin mango cubes as affected by drying techniques, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.04.015
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Research note
Total phenolics, carotenoids and antioxidant properties of Tommy Atkin mango cubes as affected by drying techniques Dalbir Singh Sogi a, b, *, Muhammad Siddiq a, c, Kirk D. Dolan a, d a
Department of Food Science and Human Nutrition, Michigan State University, East Lansing MI 48824, USA Department of Food Science and Technology, Guru Nanak Dev University, Amritsar 143 005, India c Food Science Consultant, Windsor, Canada d Department of Biosystems & Agricultural Engineering, Michigan State University, East Lansing, MI 48824, USA b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 26 June 2013 Received in revised form 22 January 2014 Accepted 4 April 2014 Available online xxx
Mango (Mangifera indica L) cubes were dehydrated using different techniques; lyophilization or freezedrying, cabinet (hot-air), vacuum and Infra-red (FD, CD, VD, IRD, respectively). Total phenolics, carotenoids, ascorbic acid contents and antioxidant properties (ABTS, DPPH, FRAP, ORAC) of mango powder were determined. Mango powder contained high quantity of phenolics (936.2e1725.2 mg GAE/100 g db, with highest in FD and lowest in CD samples), ascorbic acid (97e225 mg/100 g db, highest in FD and lowest in IRD samples) and total carotenoids (3.3e5.2 mg/100 g db). Freezeedried powder had the highest antioxidant properties than those from other drying techniques. ORAC values varied from 408 to 651 m mol TE/100 g db. Solubility of cabinet-dried powder was the highest. Water and oil Absorption Index ranged between 2.54e2.87 and 1.69e2.75, respectively. Freeze dried powders had the lower bulk density than samples from other drying techniques. Physicochemical characteristics of the freeze- and cabinet-dried mango powders offer potential application in food products. Ó 2014 Published by Elsevier Ltd.
Keywords: Mango Drying Powder Antioxidant properties Carotenoids
1. Introduction Mango (Mangifera indica L.) is a widely consumed tropical fruit in fresh or processed form throughout the world. This fruit has limited storage life since it cannot be stored at low temperatures because of its susceptibility to chilling injury. Moreover, mangoes need to be treated with hot water as quarantine requirement which accelerates the ripening process (Kim, Lounds-Singleton, & Talcott, 2009). These limitations lead to substantial postharvest losses creating massive quantity of culled fruit as bio-waste, which offers a potential to be developed into value-added products. Polyphenols, carotenoids, and vitamins impart healthpromoting properties to mango due to their antioxidant activities (Dorta, Lobo, & González, 2012a; Siddiq, Sogi, & Dolan, 2013; Sogi, Siddiq, Roidoung, & Dolan, 2012) and the fiber content of mango offers potential for its use in bakery products (Vergara-Valencia et al., 2007). Since mangoes are susceptible to decomposition because of their high water content and nutrients, drying can
* Corresponding author. Department of Food Science and Technology, Guru Nanak Dev University, Amritsar 143 005, India. Tel.: þ91 183 2258802x3217; fax: þ91 183 2258820. E-mail addresses: [email protected], [email protected] (D.S. Sogi).
effectively preserve this fruit while offering expanded usage in different food products. The method of drying can have a negative impact on quality; for example, hot air drying was shown to have negative effect on the antioxidant properties of mango (Dorta, Lobo, & Gonzalez, 2012b). Currently, mango slices are dried by dipping in sugar for marketing as a snack product; however, presently, dried mangoes for use in various food applications are not available commercially. The objective of this study was to evaluate different methods for drying mango and evaluate the antioxidant and functional properties of dried mangoes powders. 2. Materials and methods 2.1. Materials Market-ripe Tommy Atkin mangoes with green-purple peel, firm texture and light yellow flesh were procured from a local source. Fruits were sorted, washed, and sanitized (5-min dip in Fruit & Vegetable Wash at 3.75 g/L water; SC Johnson Professional, Sturtevant, WI, USA). Mangoes were peeled/diced manually using stainless steel knives to get w10 mm cubes. All chemicals used in this study were of analytical grade and were purchased from SigmaeAldrich (St Louis, MO, USA) and W.W.
http://dx.doi.org/10.1016/j.lwt.2014.04.015 0023-6438/Ó 2014 Published by Elsevier Ltd.
Please cite this article in press as: Sogi, D. S., et al., Total phenolics, carotenoids and antioxidant properties of Tommy Atkin mango cubes as affected by drying techniques, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.04.015
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Grianger, Inc. (Lake Forest, IL, USA). Unless noted otherwise, all extractions/dilutions were made using 80:20 methanolewater (methanol-80). 2.2. Drying of mango cubes Four drying techniques were employed: 1) Freeze drying (FD) e Samples were frozen at 20 C and dried in a pilot-scale lyophilizer (Vertis Company Inc., Gardiner, NY, USA) with the condenser temperature and chamber vacuum at 55 C and 4 Pa respectively; 2) Hot-air/Cabinet dying (CD) e samples were dried in a cabinet dryer (Proctor and Schwartz Inc., Philadelphia, PA, USA) operated at 60 2 C with constant air circulation; 3) Vacuum drying (VD)e Samples were kept in a vacuum oven (Sheldon Manufacturing Inc., Cornelius, OR, USA) set at 60 2 C and vacuum was maintained at 66.7 kilo-Pascal; 4) Infra-red drying (IRD) e The mango cubes were dried in a custom-made IR heating unit consisting of aluminum housing, with two 40-Watt IR bulbs. The drying was terminated based on the appearance of dehydrated mango cubes. The dried mango cubes were ground using a coffee grinder to pass through US40 Sieve (0.5 mm), packaged in polyethylene bags and stored at 20 C until analyzed. The mango powders were used for analyzing antioxidant, physicoechemical and functional properties. 2.3. Total phenolics, ascorbic acid and carotenoids analysis Total phenolics, as gallic acid equivalent (GAE), were determined according to Singleton and Rossi (1965). Briefly, 1 g samples were mixed with 20 mL of methanol-80, agitated on water-bath shaker for 1 h, followed by centrifugation (10,000 g for 10 min). Supernatants were collected and residues were re-extracted twice using 10 mL of methanol-80 by 1-min vortexing and centrifugation (10,000 g for 5 min). Mango powders were extracted and titrated against indophenol dye (2, 6 dichloro indophenol, sodium salt) to determine ascorbic acid content (AOAC, 1991). For total carotenoids, samples were extracted with hexane:acetone (7:3) solution and after phase transfer the absorbance was read at 450 nm using a spectrophotometer (Milton Roy, Pennsylvania, USA) following Davis, Collins, Fish, Tadmor, Webber, & Perkins-Veazie (2007). Total carotenoids were determined as b-carotene equivalent using a standard curve prepared with pure b-carotene (0.5e2.5 mg/mL). 2.4. Antioxidant properties Sample extraction protocol for antioxidant analysis was the same as for total phenolics. The antioxidant capacities were expressed as m mol trolox equivalent (TE)/g db. 2.4.1. ABTS assay The ABTS (2,20 -Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) antioxidant activity was determined using ABTSþ radical cation decolorization assay (Re et al., 1999), with little modification. Briefly, 7 mmol/L ABTS solution and 2.45 mmol/ L potassium persulfate were mixed in 1:1 ratio and allowed to stand in the dark for 12e16 h to produce ABTS radical cation (ABTSþ) stock solution. The ABTSþ working solution (3 mL) and 30 mL of blank, standard or sample were mixed and the absorbance was measured at 734 nm after 6 min using a spectrophotometer. The blank was run with methanol-80 and standard curve was prepared using 0.3e1.5 mmol Trolox/L. 2.4.2. DPPH assay Radical scavenging activity of mango powders was determined following Brand-Williams, Cuvelier, and Berset (1995).
Briefly, one part of stock solution of 2,2-Diphenyl-1picrylhydrazyl or DPPH (0.24 g/100 mL methanol) was diluted with ten parts methanol-80 to get working solution having absorbance of 1.1 0.02 at 515 nm. Blank, standard or samples (0.6 mL) and 3.0 mL of DPPH working solution were mixed, kept in dark for 20 min and absorbance was recorded at 515 nm. Standard curve was prepared to calculate DPPH activity using 50e250 mmol Trolox/L. 2.4.3. Ferrric reducing antioxidant power (FRAP) assay The ferric reducing ability of dried mango powders was measured following Benzie and Strain (1996). The stock solutions 300 mmol/L acetate buffer, 10 mmol/L 2,4,6-Tris(2-pyridyl)-striazine (TPTZ) solution in 40 mmol/L HCl, and 20 mmol/L FeCl3$6H2O solution were prepared. The fresh working solution was prepared by mixing acetate buffer, TPTZ solution, and ferric chloride solution in 10:1:1 ratio respectively. Blank, standard or samples (0.3 mL) were mixed with 3 mL working solution and absorbance was read after 5 min at 595 nm. Methanol-80 and Trolox (50e250 mmol/L) were used for blank and standard curve respectively. 2.4.4. Oxygen radical absorbance capacity (ORAC) assay The analysis was carried out following Huang, Ou, HampschWoodill, Flanagan, and Prior (2002). Briefly, 150 mL of fluorescein (20 nmol/L) was added to the designated wells of a 96-wells black plate, followed by the addition of 25 mL of blank, standard (Trolox 25e100 mmol/L) or samples to the designated wells. The plate was incubated at 37 C for 30 min in Microplate Reader (Biotek Instruments, Winooski, VT, USA). Then, 25 mL of freshly prepared 2, 20 Azobis (2-methylpropionamidine) dihydrochloride (153 mmol/L) was added to all the designated wells. Fluorescence was monitored using 485 nm excitation and 528 nm emissions at 2 min intervals for 180 min. 2.5. Physicoechemical analysis and functional properties Dehydrated samples (w2.5 g) were analyzed for moisture content using IR moisture meter (Denver Instrument, Bohemia, NY, USA). Titratable acidity of dehydrated mango was determined by taking 0.5 g of sample in 20 mL distilled water, adding two drops of phenolphthalein and titrating against standardized 0.1 mol/L NaOH solution. The pH was measured by taking 0.5 g sample in 50 mL distilled water using Oakton pH meter (Eutech Instruments, Singapore). Loose and packed bulk density of the mango powder was determined by transferring 10 g mango powder to a 250 mL measuring cylinder and measuring its loose and packed volume (CRA, 1998). Solubility of mango powder was determined using the method of (Cano-Chauca, Stringheta, Ramos, & Cal-Vidal, 2005) by dispersing 1 g mango powder in 100 mL water, blending, centrifuging (3000 g, 5 min) and drying supernatant at 105 C for 5 h). The water/oil absorption indices (WAI/OAI) were determined using methods described by Beuchat (1977) by mixing 1 g of sample with 10 mL of distilled water or oil for 30 s, standing for 30 min, centrifugation at 5000 g for 30 min, draining and measuring gain in weight. 2.6. Statistical analysis All the experiments were done using three replicates and data reported as mean standard deviation. Data were analyzed using JMP 9.0 software (SAS Institute, Inc., Cary, North Carolina, USA). The significant difference comparisons were made by Tukey’s HSD test (p 0.05).
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3. Results and discussion 3.1. Total phenolics, ascorbic acid and carotenoids 3.1.1. Total phenolics Drying methods affected phenolics content, ranging from 963.2 mg GAE/100 g db in VD samples to 1725.2 GAE/100 g db in FD samples (Fig. 1a). The highest content observed in FD samples might be due to no heat used in this method. Statistical analysis revealed that CD and VD samples contained significantly (p 0.05) lower phenolic content as compared to FD and IRD. Ice crystals,
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formed within the tissue matrix during freeze drying, rupture the cell structure facilitating solvent extraction and consequently high extraction of phenolic compounds (Shih, Kuo, & Chiang, 2009). Infrared dried sample had high phenolic content which might be due to non-enzymatic conversion of phenolic precursors to new phenolic compounds as in case of microwave drying (Soong & Barlow, 2004). Total phenolic content of freeze dried powder from Tommy Atkins mangoes has been reported to be 825 mg GAE/ 100 g (Hung, 2012). Our results showed higher values of phenolic content of mango powder than reported by these researchers, which might be attributed differences in fruit maturity or horticultural practices. 3.1.2. Ascorbic acid Dried mango powders contained ascorbic acid varying from 97.59 to 225.38 mg/100 g db (Fig. 1b). Ascorbic content of powders exhibited the negative effect of heat damage. Statistical analysis indicated significantly lower ascorbic acid content in powders of CD, VD and IRD involving heat during drying (p 0.05). Ndawula, Kabasa, and Byaruhanga (2004) reported that ascorbic acid content of ripe mango fruit was 164.3 mg/100 g db, which reduced to 25.4e68.5 mg/100 g db on drying. The ascorbic acid values obtained in present study were in close agreement to those reported previously. 3.1.3. Carotenoids The total carotenoids content was 3.28 and 5.17 mg/100 g db in IRD and FD samples, respectively (Fig. 1c). Drying showed a significant effect of heat on total carotenoids with the highest levels in lyophilized samples (p 0.05). Ndawula et al. (2004) reported bcarotene contents of mango to be 5.9 mg/100 g db, which were degraded on drying to 0.34e1.58 mg/100 g db level. The carotenoids content values were within the range of previously reported and supported the declining trends in values with driers operating at higher temperature. 3.2. Antioxidant properties 3.2.1. ABTS method Antioxidant properties of the dried mango samples varied from 50.7 to 103.8 m mol TE/g db (Fig. 2a). There was significant decrease in antioxidant properties of mango powder with drying technique involving heat during drying (p 0.05). Hung (2012) reported ABTS scavenging activities of dehydrated mango varying from 46.7 to 73.8 m mol TE/g db. Antioxidant activity of dried mango flesh was 27.1 m mol/g db ascorbic acid equivalent using ABTS assay (Soong & Barlow, 2004). The values obtained for antioxidant capacity as Trolox equivalent are within the close range of previously reported results. 3.2.2. DPPH method The DPPH antioxidant values varied from 34 to 88.6 m mol TE/ g db in dehydrated mango powder. The antioxidant capacity significantly changed with the drying techniques employed (p 0.05). DPPH values in green and ripe pulp of mango were 12.2 and 9.8 m mol TE/g db, respectively (Aziz, Wong, Bhat, & Cheng, 2012). The DPPH radical scavenging activity varied from 36.5 to 52.0 m mol TE/g db in dried Tommy Atkin mango flesh (Hung, 2012). The previously reported values support the present data for Tommy Atkin mango.
Fig. 1. Effect of different drying methods on total phenolics, ascorbic acid, and total carotenoids content of dried mango powder (FD e Freeze drying; CD e Cabinet drying; VD e Vacuum drying; IRD e Infrared drying).
3.2.3. FRAP method The values obtained by FRAP assay were lower than those obtained by ABTS or DPPH methods but the pattern was similar (Fig. 2c). FRAP values varied from 41 to 81 m mol TE/g db for the
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Fig. 2. Effect of drying techniques on the antioxidant properties (a) ABTS, (b) DPPH, (c) FRAP, (d) ORAC, of dried mango powder (FD e Freeze drying; CD e Cabinet drying; VD e Vacuum drying; IRD e Infrared drying).
dried mango powder. Drying techniques were shown to have a significant impact on FRAP values of powders (p 0.05). Soong and Barlow (2004) reported mango cubes had antioxidant activity of 36.6 m mol/g db, ascorbic acid equivalent, using FRAP assay. Mango pulp from green and ripe fruit showed FRAP value of 16.42 and 15.30 m mol TE/g db, respectively (Aziz et al. 2012). Our data on antioxidant activity for mango powder were comparable to those reported previously. 3.2.4. ORAC method The antioxidant activity measured by ORAC for dried powders from different drying methods was 408e651 m mol TE/g db (Fig. 2d). Statistical analysis indicated significant change in ORAC values of powders with different dryers used (p 0.05), however, FD and IRD samples values did not vary significantly. Hung (2012) reported that hydrophilic ORAC values varied from 32 to 62.1 m mol TE/g db whereas lipophilic ORAC values varied from 1.2 to 2.5 m mol TE/g db in dehydrated mango flesh using sun, air, freeze, vacuum and microwave techniques. The ORAC value obtained in present study are higher than reported values in literature which might be due to variability in material used.
3.3. Physicoechemical analysis 3.3.1. Moisture content, pH, titratable acidity and solubility Dehydrated mango powders were analyzed for selected physicochemical properties that are important for handling and utilization of dried ingredients. 3.3.1.1. Moisture content. The initial moisture content of raw mango cubes was 86.85 g/100 g. The final moisture content varied from 5.86 to 10.61 g/100 g on wet basis after dehydration (Table 1). The variation in the final moisture was statistically significant (p 0.05), which was due to the subjective method used to terminate drying process based on appearance of the product. The results are therefore given on the dry basis (db) to offset any variations due to moisture content. The initial moisture content values reported in the literature were lower than those observed in the present study which might be due to the variation in fruit maturity and method of analysis employed. 3.3.1.2. pH and titratable acidity. It is an important parameter for blending with pH sensitive food like milk and other dairy products.
Table 1 Effect of drying techniques on the physicoechemical properties of mango powder. Parameters Moisture (g/100 g wb) PH Titratable acidity (g/100 g db) Solubility (g/100 g db) Water Absorption Index, WAI (g/g db) Oil Absorption Index, OAI (g/g db) Bulk density, loose (g/mL wb) Bulk density, packed (g/mL wb)
FD 9.83 3.65 7.86 77.60 2.76 2.75 0.17 0.39
CD
bc
0.22 0.03bc 0.57a 1.69a 0.16ab 0.19a 0.02c 0.05c
7.24 3.72 6.74 78.69 2.87 1.93 0.44 0.63
VD
ab
1.77 0.04b 0.41ab 0.34a 0.17ab 0.07b 0.01b 0.02ab
5.86 3.83 6.22 74.17 2.54 1.69 0.54 0.69
IRD
a
0.74 0.02a 0.52b 1.00a 0.07b 0.18b 0.06a 0.03a
10.61 3.63 7.52 66.80 3.14 1.95 0.41 0.57
0.48c 0.03c 0.55ab 5.09b 0.29a 0.15b 0.08b 0.05b
FD e Freeze drying; CD e Cabinet drying; VD e Vacuum drying; IRD - Infrared drying. Values are given as Mean SD. Means sharing different letters in rows are significantly different from each other (p 0.05). wb e wet weight basis; db e dry weight basis.
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The pH of powders was in the range of 3.63e3.72 (Table 1) and varied significantly due to drying method used (p 0.05). The titrable acidity as anhydrous citric acid equivalents in powder ranged from 6.22 to 7.86 g/100 g db (Table 1). The acidity decreased in heated samples during drying as compared to lyophilized sample. The heat might induce Maillard’s reaction involving acid and proteins resulting in slight decrease in acidity. Statistical analysis revealed that VD mango powder had significantly lower acidity values than freeze dried samples. 3.3.1.3. Solubility. Results indicated solubility values of 67e79 g/ 100 g db in mango powders due to the presence of sugars and other soluble matters. Statistical analysis indicated significant change in solubility with types of drying techniques used (p 0.05). Solubility of mango powder was observed to be 89.70, 94.38, 95.31 and 90.79 g/100 g in freeze, drum, spray and refractive window dried samples, respectively (Caparino et al., 2012). The solubility values observed in the present study were lower than those reported in the literature previously, which might be due to different ripening stage and cultivar type since Caparino et al. (2012) used 95e100% ripe mangoes of ‘Carabo’ cultivar whereas in current study slightly ripe ‘Tommy Atkin’ mangoes were used. 3.3.2. Water/oil absorption index (WAI, OAI) The WAI shows the amount of the water uptake by per unit mass of dried powder. The WAI of dried mango powder was 2.54e3.14 g/ g db (Table 1). Statistical analysis revealed WAI varied significantly with types of drying systems in three samples (p 0.05). Present results revealed lower WAI values for mango powder as compared to those reported previously. Statistical analysis revealed that OAI of dried powders (1.69e2.75 g/g db) differed significantly with the drying method used. 3.3.3. Bulk density The loose and packed bulk density values were lower for FD mango powder (0.17 and 0.39 g/mL, respectively) indicating a fluffy product (Table 1). Other drying techniques yielded products with higher bulk density values, which might be due to excessive shrinkage during dying. The packed and loose bulk density can be correlated with the solubility indicating lower density products were more soluble. Bulk density of mango powder was observed to be 0.44, 0.76, 0.46 and 0.68 g/mL in freeze, drum, spray and refractive window dried samples, respectively (Caparino et al., 2012). Bulk density of green and ripe mango pulp dehydrated in hot air dryer was 0.69 and 0.68 g/g db respectively (Aziz et al., 2012). The values of bulk densities in present investigation were comparable with those reported in the literature. 4. Conclusion Mango cubes can be preserved by dehydration for use in different food applications. Total phenolics, ascorbic acid, carotenoids and antioxidant properties of dehydrated powders were lower in hot air, vacuum and IR drying technique involving heat compared to freeze drying. Solubility, water and oil absorption values of dried mango powders were adequate for their utilization. The dehydrated mango can be utilized for enhancing flavor and added fiber and antioxidant-rich phytochemicals for preparing healthy and nutritious food products, especially snacks.
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Acknowledgment Authors thank the U.S. Fulbright Program for Dalbir S. Sogi’s Research Fellowship and Project GREEEN at Michigan State University for partial financial support of this research. References AOAC. (1991). Association of official analytical chemists. Washington, DC. Aziz, N. A. A., Wong, L. M., Bhat, R., & Cheng, L. H. (2012). Evaluation of processed green and ripe mango peel and pulp flours (Mangifera indica var Chokanan) in term of chemical composition, antioxidant compounds and functional properties. Journal of Science of Food & Agriculture, 92, 557e563. Benzie, I. F. F., & Strain, J. J. (1996). The ferric reducing ability of plasma (FRAP) as a measure of “antioxidant” power: the FRAP assay. Analytical Biochemistry, 239, 70e76. Beuchat, L. R. (1977). Functional and electrophoretic characteristics of succinylated peanut flour protein. Journal of Agriculture & Food Chemistry, 25, 258e 261. Brand-Williams, W., Cuvelier, M. E., & Berset, C. (1995). Use of a free radical method to evaluate antioxidant activity. LebensmitteleWissenschaft und Technologie, 28, 25e30. Cano-Chauca, M., Stringheta, P. C., Ramos, A. M., & Cal-Vidal, J. (2005). Effect of the carriers on the microstructure of mango powder obtained by spray drying and its functional characterization. Innovative Food Science & Emerging Technologies, 5, 420e428. Caparino, O. A., Tang, J., Nindo, C. I., Sablani, S. S., Powers, J. R., & Fellman, J. K. (2012). Effect of drying methods on the physical properties and microstructures of mango (Philippine ‘Carabao’ var.) powder. Journal of Food Engineering, 111, 135e 148. CRA. (1998). Bulk density (B-16). Analytical methods. Washington, DC, USA: Corn Refiners Association, Inc. Davis, A. R., Collins, J., Fish, W. W., Tadmor, Y., Webber, C. L., & Perkins-Veazie, P. (2007). Rapid method for total carotenoid detection in canary yellow-fleshed watermelon. Journal of Food Science, 72, S319eS323. Dorta, E., Lobo, M. G., & González, M. (2012a). Using drying treatments to stabilise mango peel and seed: effect on antioxidant activity. LWT e Food Science & Technology, 45, 261e268. Dorta, E., Lobo, M. G., & Gonzalez, M. (2012b). Reutilization of mango byproducts: study of the effect of extraction solvent and temperature on their antioxidant properties. Journal of Food Science, 71, 80e88. Huang, D. J., Ou, B. X., Hampsch-Woodill, M., Flanagan, J. A., & Prior, R. L. (2002). High-throughput assay of oxygen radical absorbance capacity (ORAC) using a multichannel liquid handling system coupled with a microplate fluorescence reader in 96-well format. Journal of Agriculture & Food Chemistry, 50, 4437e 4444. Hung, L. M. (2012). Antioxidative effects of mango wastes on shelf life of pork products. PhD thesis. New Zealand: Lincoln University. Kim, Y., Lounds-Singleton, A. J., & Talcott, S. T. (2009). Antioxidant phytochemical and quality changesassociated with hot water immersion treatment of mangoes (Mangifera indica L.). Food Chemistry, 115, 989e993. Ndawula, J., Kabasa, J. D., & Byaruhanga, Y. B. (2004). Alterations in fruit and vegetable b-carotene and vitamin C content caused by open-sun drying, visqueen-covered and polyethylene-covered solar-dryers. African Health Sciences, 4(2), 125e130. Re, R., Pellegrini, N., Proteggente, A., Pannala, A., Yang, M., & Rice-Evans, C. (1999). Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free Radical Biology & Medicine, 26, 1231e1237. Shih, M. C., Kuo, C. C., & Chiang, W. (2009). Effects of drying and extrusion on colour, chemical composition, antioxidant activities and mitogenic response of spleen lymphocytes of sweet potatoes. Food Chemistry, 117(1), 114e121. Siddiq, M., Sogi, D. S., & Dolan, K. (2013). Antioxidant properties, total phenolics, and quality of fresh-cut ‘Tommy Atkins’ mangoes as affected by different pretreatments. LWT-Food Science & Technology, 53, 156e162. Singleton, V. L., & Rossi, J. A. (1965). Colorimetry of total phenolics with phosphomolybdic-phosphotungstic acid reagents. American Journal of Enology and Viticulture, 16, 144e158. Sogi, D. S., Siddiq, M., Roidoung, S., & Dolan, K. D. (2012). Total phenolics, carotenoids, ascorbic acid and antioxidant properties of fresh-cut mango (Mangifera indica L., cv. Tommy Atkin) as affected by infra-red heat treatment. Journal of Food Science, 77, C1197eC1202. Soong, Y. Y., & Barlow, P. J. (2004). Antioxidant activity and phenolic content of selected fruit seeds. Food Chemistry, 88, 411e417. Vergara-Valencia, N., Granados-Pérez, E., Agama-Acevedo, E., Tovar, J., Ruales, J., & Bello-Pérez, L. A. (2007). Fibre concentrate from mango fruit: characterization, associated antioxidant capacity and application as a bakery product ingredient. LWT e Food Science & Technology, 40, 722e729.
Please cite this article in press as: Sogi, D. S., et al., Total phenolics, carotenoids and antioxidant properties of Tommy Atkin mango cubes as affected by drying techniques, LWT - Food Science and Technology (2014), http://dx.doi.org/10.1016/j.lwt.2014.04.015