soursop. Those that had the lowest AOC were carrots, lettuce, black sapote, cucumbers and celery. Hydrophilic extracts of most commodities had higher AOC.
Antioxidant Capacity and Correlation with Phenolic Compounds and Carotenoids in 40 Horticultural Commodities E.M. Yahia and A. Barrera Facultad de Ciencias Naturales Universidad Autonoma de Queretaro Ave de las Ciencias, Juriquilla Queretaro, 76230, Qro. Mexico Keywords: fruit, vegetables, nutrition, health, FRAP, DPPH Abstract The consumption of fresh fruits and vegetables has been correlated with better health and prevention of several illnesses. Fruits and vegetables contain many phytochemicals, such as phenolic compounds and carotenoids, many of them are antioxidants. The objective of this work was to determine the antioxidant capacity (AOC) of 40 horticultural commodities sampled from the markets in Queretaro, Mexico, and correlate it with their phenolic and carotenoid content. AOC was determined by FRAP (ferric ion reducing antioxidant power) and DPPH (2,2-difenil1-picril-hidrazil). Total carotenoids and total phenolic compounds were measured spectrophotometrically. Results showed great variations between the different commodities. Fruits that had the highest AOC were red bell pepper, guava, ‘Ataulfo’ mango, yellow bell pepper, ‘Manila’ mango, green bell peppers, and soursop. Those that had the lowest AOC were carrots, lettuce, black sapote, cucumbers and celery. Hydrophilic extracts of most commodities had higher AOC than the lipophilic extracts. Commodities that had the highest carotenoids content were carrots, celery, yellow and red bell peppers, and papaya. Commodities with the lowest carotenoid content were radish, prickly pear, pineapples, pears, onions, black sapote, banana and apples. Most commodities had high phenolic content. Those with low phenolic content were carrots, limes and white onions. AC measured by FRAP correlated positively with total carotenoids content in red bell peppers, ‘Red Delicious’ apples, limes and guava, and correlated positively with total phenolic content in avocados, soursop, tomato, ‘Manila’ mango, papaya and pears. AOC measured with DPPH correlated positively with total phenolic content in hot peppers, limes, ‘Tommy Atkins’ mangoes, melons, oranges and papaya, and correlated positively with carotenoids content in guava, tomatoes, lettuce, limes and yellow bell peppers. INTRODUCTION The consumption of fresh fruits and vegetables has been correlated with better health and prevention of several illnesses. Fruits and vegetables contain many phytochemicals, such as phenolic compounds and carotenoids, many are antioxidants (Yahia, 2009). Clinical and epidemiological studies have shown that the consumption of natural antioxidant-rich foods such as fruits and vegetables are beneficial to health due to their capacity to prevent some health problems, such as heart diseases and cancer, cataracts, macular degeneration, and neurological diseases, and the beneficial effects of fruits and vegetables are attributed to their high content of antioxidant compounds that diminish the free radical oxidative stress, which is responsible for cellular damage (Yahia, 2009; Garcia-Solis et al., 2008, 2009). However, there is a lack of information regarding the bioactive compounds content and antioxidant capacity (AOC) of many fruits and vegetables. Various methods have been developed to measure the AOC of fruits and vegetables, but results usually vary depending on type of product and the method used. For this reason it is recommended that at least two different methods be used to measure AOC in any given sample. In this study, the content of total soluble phenols (TSP) and Proc. 6th International Postharvest Symposium Eds.: M. Erkan and U. Aksoy Acta Hort. 877, ISHS 2010
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total carotenoids (TC) have been measured and correlated with the AOC in 40 fresh horticultural crops sampled in Queretaro, Mexico. MATERIALS AND METHODS Forty fresh horticultural commodities (Tables 1 and 2) were studied. All products were sampled from supermarkets in Queretaro, Mexico, and taken to the laboratory of Phytochemicals and Nutrition of the Faculty of Natural Sciences of the Autonomous University of Queretaro. Upon arrival, they were washed, physically and chemically characterized by measuring weight, internal and external color and total soluble solids content (TSS). All products were used at the maturity preferred by consumers for their fresh consumption. AOC was determined by FRAP (ferric ion reducing antioxidant power), DPPH (2,2-difenil-1-picril-hidrazil), and total carotenoids and total phenolic compounds were measured spectrophotometrically (Corral-Aguayo et al., 2008; Yahia et al., 2006). RESULTS AND DISCUSSION Physical and chemical characteristics of the forty tested horticultural products were determined at the beginning of the experiment to establish the ripeness stage and quality based on internal and external color, and total soluble solids (TSS) (data not shown). Lettuce had the lowest TSS (2%), while mamey sapote had the highest TSS (19.44%). Color data corresponded with the stage of maturity for each product, indicating for example that papaya, guava, avocado, mango, and prickly pear fruit were ripe, black sapote was over-ripe and nopal was at its horticultural maturity stage as commonly used for human consumption (data not shown). Results showed great variations between the different commodities with regard to AOC (Fig. 1). Fruits that had the highest AOC were red bell pepper, guava, ‘Ataulfo’ mango, yellow bell pepper, ‘Manila’ mango, green bell peppers and soursop. Those that had the lowest AC were carrots, lettuce, black sapote, cucumbers and celery. Hydrophilic extracts of most commodities had higher AOC than the lipophilic extracts. Table 1 shows the classification of fruits and vegetables according to their antioxidant capacity measured by DPPH or FRAP. Commodities that had the highest carotenoids content were carrots, celery, yellow and red bell peppers and papaya. Commodities with the lowest carotenoid content were radish, prickly pear, pineapples, pears, onions, black sapote, banana and apples (data not shown). Most commodities had high phenolic content. Those with low phenolic content were carrots, limes and white onions (data not shown). AOC measured by FRAP correlated positively with total carotenoids content in red bell peppers, ‘Red Delicious’ apples, limes, and guava, correlated positively with total phenolic contents in avocados, soursop, tomato, ‘Manila’ mango, papaya and pears (Table 2). AOC measured with DPPH correlated positively with total phenolic contents in hot peppers, limes, ‘Tommy Atkins’ mangoes, melons, oranges, and papaya, and correlated positively with carotenoids content in guava, tomatoes, lettuce, limes, and yellow bell peppers (Table 2). CONCLUSIONS It is very important to determine the antioxidant contribution of different foods such as fresh horticultural commodities. Horticultural commodities vary greatly in their AOC, and total phenolic content and carotenoid content correlate with AOC only in few of these commodities. This indicates that although total phenolic and carotenoid content are important, and many of them contribute to the antioxidant capacity of foods, several other antioxidants are also important. Literature Cited Corral-Aguayo, R., Yahia, E.M., Carrillo-Lopez, A. and Gonzalez-Aguilar, G. 2008. Correlation between some nutritional components and the total antioxidant capacity 1216
measured with six different assays in eight horticultural crops. Journal of Agricultural and Food Chemistry 56:10498-10504. García-Solís, P., Yahia, E.M. and Aceves, C. 2008. Study of the effect of ‘Ataulfo’ mango (Mangifera indica L.) intake on mammary carcinogenesis and antioxidant capacity in plasma of N-Methyl-n-Nitrosourea (MNU)-treated rats. Food Chemistry 111(2):309-315. García-Solís, P., Yahia, E.M., Morales-Tlalpan, V. and Díaz-Muñoz, M. 2009. Screening of antiproliferative effect of aqueous extracts of plant foods consumed in México on the breast cancer cell line mcf-7. International Journal of Food Science and Nutrition (in press). Yahia, E.M. 2009. The contribution of fruit and vegetable consumption to human health. In: L. De la Rosa et al. (eds.). Fruit and vegetable phytochemicals: Chemistry, nutritional value and stability. Blackwell Publishing (in press). Yahia, E.M., Ornelas-Paz, J. de J. and Gardea, A. 2006. Extraction, separation and partial identification of ‘Ataulfo’ mango fruit carotenoids. Acta Hort. 712:333-338.
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Tables
Table 1. Classification of fruits and vegetables according to their antioxidant capacity measured by DPPH or FRAP. DPPH 1. Bell pepper (red) 2. Guava 3. Mango (Ataulfo) 4. Bell pepper (yellow) 5. Mango (Manila) 6. Bell pepper (green) 7. Lime 8. Papaya 9. Plums 10. Mango (Tommy Atkins) 11. Grapefruit 12. Mamey 13. Soursop 14. Mandarin 15. Apples (Red Delicious) 16. Nopal 17. Peppers (Poblano) 18. Avocado 19. Onions (red) 20. Melon (cantaloup) 21. Pepper (Habanero) 22. Watermelons 23. Apples (Golden Delicious) 24. Celery (leaf) 25. Peppers (Jalapeño) 26. Prickly pear fruit 27. Lettuce 28. Peppers (Serrano) 29. Radish 30. Banana 31. Tomato (red) 32. Pineapples 33. Oranges 34. Pears 35. Tomato (green) 36. Onions (white) 37. Celery (stem) 38. Cucumbers 39. Black sapote 40. Carrots
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FRAP 1. Bell pepper (red) 2. Guava 3. Bell pepper (yellow) 4. Mango (Ataulfo) 5. Sour sop 6. Black sapote 7. Avocado (Hass) 8. Bell pepper (green) 9. Mango (Manila) 10. Plums 11. Mamey 12. Papaya 13. Oranges 14. Celery (leaf) 15. Peppers (Jalapeño) 16. Peppers (Serrano) 17. Banana 18. Mandarin 19. Radish 20. Grape fruit 21. Peppers (Habanero) 22. Lime 23. Prickly pear fruit 24. Peppers (Poblano) 25. Apples (Red Delicious) 26. Melon (cantaloup) 27. Onions (red) 28. Cucumber 29. Apples (Golden Delicious) 30. Mango (Tommy Atkins) 31. Tomato (red) 32. Pineapples 33. Tomato (green) 34. Onions (white) 35. Pears 36. Nopal 37. Watermelons 38. Celery (stem) 39. Carrots 40. Lettuce
Table 2. Correlations between antioxidant capacity and phenolic and phenolic and carotenoid content. Total phenolic content Total carotenoids content FRAP DPPH FRAP DPPH Apple (Golden Delicious) 0.286 -0.351 0.095 0.116 Apple (Red Delicious) 0.394 -0.008 0.554 0.123 Avocado (Hass) 0.58 0.1581 -0.196 -0.334 Banana 0.571 0.116 0.375 -0.48 Bell pepper (green) 0.222 0.582 0.23 -0.07 Bell pepper (red) -0.127 0.001 0.653 -0.121 Bell pepper (yellow) -0.08 0.08 -0.06 0.553 Black sapote -0.0793 0.071 0.0217 0.481 Carrots 0.13 0.292 -0.595 0.351 Celery (stem) - 0.115 0.166 0.204 0.102 Celery (leaf) 0.1006 -0.134 -0.298 -0.284 Cucumber -0.1137 -0.0575 0.0603 0.0179 Grapefruit -0.12 0.0267 -0.007 -0.126 Guava -0.307 0.0747 0.52 0.911 Lettuce 0.348 -0.427 0.456 0.434 Lime 0.205 0.417 0.57 0.438 Mamey 0.251 0.198 -0.791 -0.571 Mandarin -0.254 0.284 0.32 0.368 Mango (Ataulfo) -0.22 -0.105 -0.623 -0.08 Mango (Tommy Atkins) -0.307 0.569 -0.193 -0.593 Mango (Manila) 0.627 0.096 -0.542 -0.312 Melon (cantaloup) -0.05 0.64 -0.61 0.301 Nopal -0.08 0.329 0.148 0.446 Onion (red) -0.23 0.007 -0.045 0.142 Onion (white) 0.05 -0.05 -0.07 0.31 Oranges 0.004 0.759 0.035 -0.105 Papaya 0.793 0.581 -0.01 -0.07 Pears 0.419 0.217 0.259 0.211 Pepper (Poblano) 0.142 0.081 0.39 -0.24 Pepper (Serrano) 0.083 -0.484 0.15 -0.434 Pepper (Habanero) 0.14 0.025 0.0009 0.209 Pepper (Jalapeño) 0.353 0.495 -0.48 0.219 Pineapples -0.28 0.16 0.344 -0.017 Plum 0.007 -0.286 0.138 0.143 Prickly pear fruit -0.23 0.035 -0.217 -0.519 Radish 0.353 -0.0252 -0.235 0.335 Soursop 0.618 0.399 -0.34 -0.304 Tomato 0.497 -0.209 0.251 0.511 Tomato (green) 0.402 -0.387 0.658 -0.05 Watermelon 0.322 0.336 0.059 0.194 Fruits and vegetables
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Appl e olden App(G le (R D ed Delicious ) e l ic Avocious) Bell a do p B B eppe anan Bell ell peppr e(Greena) pepp e r (Red) Blacr (Yellow k sap ) ot Cele Carre r y Cele (Leaot ry f) Cuc(uStem) m Grap ber ef Guarvuit Lettu a ce Mam ey saLime Man Mandpote g a Man Mangoo (Ataulfrin o g o (T ( M a Melo omy nila)) n (Ca Atkin ntalo s) upe Onio Nopa)l n Onio (Red n (W h ) Oranite) Papage Pepp ya e Pepp r (Hab Pear Pepper (Jalaanero) Pepper (Pobpeño) er (S lano) e Pinerrano) apple Plum Prick (Red) ly p Radei ar Tom Sour sh a s Tomto (Greeop ato ( n) Wate Red) rmel on
Figures
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Fig. 1. Comparison between the total antioxidant capacity (hydrophilic and lipophilic) of 40 horticultural commodities measured by the DPPH and FRAP assays.
