TN-1171 APPLICATIONS Characterization of Capsaicinoids and Related Pungent Agents in Chili Peppers by LC/MS/MS Seyed Sadjadi, J. Preston, Zeshan Aqeel, and Brian Rivera Phenomenex, Inc., 411 Madrid Ave., Torrance, CA 90501 USA Introduction Experimental Conditions Capsaicin and related compounds are responsible for pungency, the burning sensation associated with chili peppers and other Extraction Procedures spicy foods. In high concentrations, all capsaicinoids produce 250 or 500 g of chili peppers (depending on pepper size) were burning sensations throughout the mouth, throat and mucous blended for an extended period of time (approximately 5 mins membrane; in low concentrations they affect only specific areas of or until all seeds were crushed) with Ethanol to contain appro- the mouth and throat. As a result, low level pungent compounds ximately 60-70% of alcohol. An aliquot of the puree was remo- can enhance the food flavor1-4. Additionally, capsaicin may have ved and filtered using a Phenex™ PTFE Membrane with pore size clinical applications, including antioxidant properties5 and is used of 0.45 µm, 25 mm syringe filter, Part No. AF0-1102-12 prior as the main ingredient in several over-the-counter topical oint- to analysis with LC/MS/MS. The rest of the puree was retai- ments for the treatment of pain and inflammation. ned to prepare purified capsaicinoids by Prep Chromatography. Because the amount of capsaicin produced by chili peppers can LC/MS/MS Conditions vary due to environmental and weather conditions6, it is critically important for the food industry to effectively quantitate capsa- Column: Kinetex® 5 µm C18 Dimensions: 100 x 2.1 mm icinoids. Traditionally, subjective methods were used in this pro- Part No.: 00D-4601-AN cess. In 1912, Wilber Scoville established a scale to demonstrate Mobile Phase: A: 0.1 % Formic acid in Water the pungency of chili peppers based on taste-test1. B: 0.1 % Formic acid in methanol Flow Rate: 0.6 mL/min To more accurately quantitate pungency, concentration values of Gradient: Time (min) B (%) three major capsaicinoids (capsaicin, dihydrocapsaicin, and nor- 0.0 30 7.0 90 dihydrocapsaicin) are determined by HPLC. The concentration 9.0 90 (in ppm) is then multiplied by a pungency factor for each species 9.1 30 and added together to arrive at a corresponding Scoville Heat Unit 12.0 30 value.2 Injection Volume:: 2 µL Temperature: Ambient In this technical note, capsaicinoids were extracted from chili pep- Detection: API 4000™ triple quadrupole LC/MS/MS pers and analyzed by a triple quadrupole LC/MS/MS system to Electrospray ionization (ESI) analyzed in positive mode System: Agilent® 1200SL LC system (Agilent Technologies, identify each capsaicinoid. Ion intensities for different chili pepper Palo Alto, CA, USA), equipped with a binary pump, extracts were then reviewed and evaluated. Autosampler Reconstitute: Reconstitute in 500 µL of mobile phase Materials and Methods Reagents and Chemicals Precursor Method • Capsaicin, dihydrocapsaicin, and nonivaimide were Precursor mass: 136.9 amu ® purchased from ChromaDex , Irvine, CA. Q1 Mass Range: 150 to 350 amu • Methanol, Ethanol and Acetonitrile were purchased from Scan Time: 2 sec Sigma-Aldrich, St. Louis, MO. • Thai, Habanero, Serrano and Jalapeno peppers were Scan mode: Profile @ 0.25 amu step size purchased from various local grocery stores Collision Energy: 25 V Jalapeno Habanero Results and Discussion Capsaicins Fragmentation Profile Capsaicin and dihydrocapsaicin were analyzed by infusion to Thai Chili determine their ionization properties and fragmentation patterns. Serrano The product ion scan revealed similarities in the fragmentati- on pattern of the two compounds. More specifically, the bond breakage between the amine group and the benzene ring appears to be predominant and common. The most abundant fragment (136.9 m/z) is displayed (Figure 1) and was used in the precursor scan analysis. For additional technical notes, visit www.phenomenex.com Page 1 of 4 TN-1171 APPLICATIONS Figure 1. Fragmentation Comparison of Capsaicin and Dihydrocapsaicin Figure 3. Comparison of Chili Pepper Extracts Using a Precursor Ion at CE of 15 V Scan, Mass Assignments: 181.9 1. Octanoic Acid vanillylamide isomers (280.2 m/z) HO 136.9 100% CH3 2. Nordihydrocapsaicin (294.2 m/z) H C NH 80% 3 Capsaicin 3. Capsaicin (306.2 m/z) O CH3 60% 136.9 O 4. Dihydrocapsaisin (308.2 m/z) 40% 5. Homocapsaicin (320.2 m/z) Rel. Int (%) 306.1 20% 181.9 6. Homodihydrocapsaicin (322.2 m/z)z 170.0 138.3 151.0 153.1 0% 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 183.9 136.9 100% HO 3 CH3 100% 4.5 80% 2 Thai H3C NH Dihydrocapsaicin O CH3 50% 60% 6 136.9 O 1 40% 0% Rel. Int (%) 308.1 2.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 min 20% 183.9 155.0 172.0 309.2 App ID 21863 0% 3 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 100% 4.5 mz/, Da Habanero 50% 2 1 6 0% Analysis of Chili Pepper Extract Comparison 2.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 min Extracts from Habanero, Serrano, Jalapeno and Thai chili peppers 3 100% 4.5 were analyzed by a precursor scan method. In this scan function, Serrano the first quadrupole scans a predetermined mass range, in this 50% 2 6 0% 1 case, 50-350 m/z. The selected ions enter the collision cell and 2.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 min undergo fragmentation at a specific energy or rolling energy, in 3 this case, 20 V. The resulting ion fragments enter the last qua- 100% drupole stage and scanned for a specific ion mass, in this case 4.5 Jalapeno 50% 2 136.90 m/z. The detected ions will be reported as corresponding 1 6 App ID 21859 0% to the mass of the ions that were selected by the first quadrupole. 2.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 min A secondary dynamic product ion scan was collected as further confirmation of capsaicinoid compounds Figure( 2). All common- ly referenced capsaicinoids are listed in Table 1. Surprisingly, Table 1. Identified Capsaicinoids in Chili Peppers based on ion intensities, in our sample set, Thai chili pepper had the highest overall concentration of capsaicinoids. In addition, Monoisotopic Prec. Mass Compound MW, Da (M+H+)+, m/z Structure nordihydrocapsaicon ratio to capsaicin was highest in the Thai chili pepper sample (Figure 3.) HO CH3 Capsaicin 305.2 306.2 H3C NH O CH3 Figure 2. Precursor Scan of Nordihydrocapsaicin in Serrano Chili Pepper O HO and MS/MS Spectrum of Nordihydrocapsaicin at CE = 20 V H3C NH CH Homocapsaicin 319.2 320.2 O 3 O H3C 5.74 5.3e7 6.22 HO CH 4.0e7 3 H3C NH O CH 2.0e7 Dihydrocapsaicin 307.2 308.2 3 6.69 O 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 min HO 27 56 85 114 142 168 196 225 254 284 313 342 H3C NH CH Homodihydrocapsaicin 321.2 322.2 O 3 294.3 9.5e4 O H3C HO 5.0e4 H3C NH CH3 0.0 Nordihydrocapsaicin 293.2 294.2 O 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 O CH3 HO 137.0 HO 2.3e5 Nonivamide 293.2 294.2 H3C NH 2.0e5 O CH3 H3C NH CH 3 O 1.5e5 O HO 1.0e5 CH3 O H3C H3C NH O 5.0e4 CH3 170.0 141.0 158.0 247.5 262.0 276.8 294.0 App ID 21864 O 0.0 The presence of multiple peaks for some of these compounds, 100 120 140 160 180 200 220 240 260 280 300 320 340 mz/, Da most notably nordihydrocapsaicin, suggest the presence of iso- mers, possibly on the fatty acid tail side. The presence of branched (e.g. isopropyl tail) and straight chain acid could possibly be one isomeric form (Figure 4). Further confirmation will require addi- tional techniques such as H-NMR data. Such an endeavor will be pursued in future work. Page 2 of 4 TN-1171 Figure 4. Isomeric Forms of Nordihydrocapsaicin and Octanoic Acid References Vanillylamide21861 Isomers in Thai Chili Pepper Extract 1. Capsaicin. Wikipedia. 28 Mar. 2014. Wikimedia Foundation. 29 Mar. 2014 6.0e7 http://en.wikipedia.org/wiki/Capsaicin. 5.0e7 4.0e7 2. Krajewsska, Anna M., and John J. Powers. “Sensory Properties of Naturally 3.0e7 Occurring Capsaicinoids.” Journal of Food Science 53 (1988): 902-05. Intensity, cps Intensity, 2.0e7 3. Reilly, Christopher A., Dennis J. Crouch, Garold S. Yost, and Alim A. Fatah. 1.0e7 “Determination of capsaicin, dihydrocapsaicin, and nonivamide in self- 0.0 defense weapons by liquid chromatography–mass spectrometry and liquid 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 min chromatography–tandem mass spectrometry.” Journal of Chromatography A 5.8e6 912 (2001): 259-67. 5.0e6 Nordihydrocapsaicin 4.0e6 4. Choi, SH, Suh, BS, Kozukue, E, Kozukue, N, Levin, CE, Friedman, M, Analysis of contents of pungent compounds in fresh korean peppers and in 3.0e6 pepper-containing foods, Journal of Agricultural and Food Chemistry, 2006, Intensity, cps Intensity, 2.0e6 54, pp 9024-9031 1.0e6 Octanoic acid App ID 21861 vanillylamide isomers Nonivamide 0.0 5.