pubs.acs.org/JAFC Published on Web 12/02/2010 © 2010 American Chemical Society J. Agric. Food Chem. 2011, 59, 163–173 163 DOI:10.1021/jf103434u Antioxidant Activity of Fresh and Processed Jalapen ˜ o and Serrano Peppers EMILIO ALVAREZ-PARRILLA, †,^ LAURA A. DE LA ROSA, †,^ RYSZARD AMAROWICZ, § AND FEREIDOON SHAHIDI* ,# † Universidad Auto´ noma de Ciudad Jua´rez, Instituto de Ciencias Biome´dicas, Departamento de Ciencias Quı´mico-Biolo´ gicas, Anillo Envolvente del PRONAF y Estocolmo s/n, Ciudad Jua´rez, Chihuahua, CP 32310, Mexico, § Division of Food Science, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, ul. Tuwima 10, 10-747 Olsztyn, Poland, and # Department of Biochemistry, Memorial University of Newfoundland, St. John’s, NL, Canada A1B 3X9. ^ Sabbatical leave at Memorial University of Newfoundland. In this research, total phenols, flavonoids, capsaicinoids, ascorbic acid, and antioxidant activity (ORAC, hydroxyl radical, DPPH, and TEAC assays) of fresh and processed (pickled and chipotle canned) Jalapen ˜o and Serrano peppers were determined. All fresh and processed peppers contained capsaicin, dihydrocapsaicin, and nordihydrocapsaicin, even though the latter could be quantified only in fresh peppers. Processed peppers contained lower amounts of phytochemicals and had lower antioxidant activity, compared to fresh peppers. Good correlations between total phenols and ascorbic acid with antioxidant activity were observed. Elimination of chlorophylls by silicic acid chromatography reduced the DPPH scavenging activity of the extracts, compared to crude extracts, confirming the antioxidant activity of chlorophylls present in Jalapen ˜o and Serrano peppers. KEYWORDS: Capsicum annuum; total phenols; flavonoids; ascorbic acid; capsaicinoids; antioxidant activity; chlorophylls INTRODUCTION Hot peppers (Capsicum annuum) are widely produced and consumed in Mexico as raw, cooked, or processed products. The northern state of Chihuahua is among the main producers of hot peppers in Mexico, especially of Jalapen˜ o varieties, with >35% of the national production ( 1 ). Hot peppers are known to be good sources of different phytochemicals, including vitamins A and C, phenolic compounds, flavonoids, and carotenoids, among others ( 2 -5 ). They are the only plants that are able to produce capsaicinoids, responsible for their characteristic hot taste. The concentrations of these compounds depend on cultivar, maturity, growing conditions, and postharvest manipulation ( 6 ). They have been described as the vegetables with the highest vitamin C content ( 7 ). Thus, they are known to present high antioxidant activity ( 4 ). Green peppers are also known to serve as a good source of chlorophylls, which, under certain conditions, may act as radical scavengers, increasing the antioxidant activity of high chlorophyll content vegetables ( 8 ). It has been estimated that hot peppers are the second most consumed vegetable by the Mexican population after tomatoes ( 1 ), with a consumption of approximately 7-9 kg/person per year ( 9 ). From this amount, approximately 75% is consumed as fresh product for the preparation of different dishes. Other commonly consumed presentations of hot peppers include pickled, dried, and smoked and in sauces. There are several varieties of hot peppers consumed in Mexico; two of the most popular varieties are Jalapen˜ o and Serrano, in both fresh and processed forms. The main processed presentations are pickled and chipotle. Chipotle is a red Jalapen˜ o pepper (last ripe state) that has been dried and smoked for a period of 4-7 days. Even though it can be sold dried, typically it is rehydrated and canned. It has been described that heat processing has a great impact on the content of phyto- chemicals and, consequently, on the antioxidant activity of fresh peppers ( 2 ). To determine the beneficial effect of the consumed fruits and vegetables in each region, it is important to characterize the main phytochemicals consumed in the diet, paying special attention to the loss of these phytochemicals in the products due to food manipulation. For this reason, the aim of the present work was to evaluate total phenols, flavonoids, ascorbic acid, capsaicinoids, and antioxidant activity of fresh and processed (pickled and chipotle canned) Jalapen˜ o and Serrano peppers. Considering that Chihuahua is the main Jalapen˜ o producer in the country, fresh Jalapen˜ os from three of the main production regions were also analyzed. Finally, the effect of chlorophylls on DPPH scavenging activity of all samples was analyzed. MATERIALS AND METHODS Chemicals. 2,2 0 -Azobis(2-methylpropionamidine) dihydrochloride (AAPH), 1,1-diphenyl-2-picrylhydrazyl (DPPH), 5,5-dimethyl-1-pyrroline- N-oxide (DMPO), 2,2 0 -azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS 2- ), 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), Folin-Ciocalteu phenol reagent, sodium carbonate, monobasic potassium phosphate, dibasic potassium phosphate, gallic acid, human low-density lipoprotein (LDL) cholesterol, ethylenediaminetetraacetic acid *Author to whom correspondence should be addressed (e-mail fshahidi@mun.ca).