Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1997 Influence of solvent extraction, maturity stage, and thermal treatment on the determination of capsaicin in capsicums (Capsicum annuum spp.) and their products Alfonso Rafael Rocha-Herrera Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Agriculture Commons, and the Food Science Commons Recommended Citation Rocha-Herrera, Alfonso Rafael, "Influence of solvent extraction, maturity stage, and thermal treatment on the determination of capsaicin in capsicums (Capsicum annuum spp.) and their products " (1997). Retrospective Theses and Dissertations. 12240. https://lib.dr.iastate.edu/rtd/12240 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. 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UMI A BeU & Howell Information Conq)any 300 North Zetb Road, Ann Aitx)r MI 48106-1346 USA 313/761-4700 800/521-0600 Influence of solvent extraction, maturity stage, and thermal treatment on the determination of capsaicin in capsicums {Capsicum armuum spp.) and their products ty Alfonso Rafael Rocha-Herrera A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Food Science and Technology Major Professor: Lester A. Wilson Iowa State University Ames. Iowa 1997 Cop5night © Alfonso Rafael Rocha-Herrera, 1997. All rights reserved. UMI Number; 9737753 Copyright 1997 by Rocha-Herrera, Alfonso Rafael All rights reserved. UMI Microform 9737753 Copyright 1997, by UMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 ii Graduate College Iowa State University This is to certify that the Doctoral Dissertation of Alfonso Rafael Rocha-Herrera has met the dissertation requirements of Iowa State University Signature was redacted for privacy. Committee Member Signature was redacted for privacy. bmmittee "^emLer Signature was redacted for privacy. Committee Member Signature was redacted for privacy. Committee Mem Signature was redacted for privacy. Major Professor Signature was redacted for privacy. For the Major Program Signature was redacted for privacy. For the Graduate College iii To my loving wife, Irma, and my tliree hearts, Alfonso Salvador, Javier, and Sandra Mireille iv TABLE OF CONTENTS ABSTRACT vi GENERAL INTRODUCTION 1 Introduction 1 Dissertation Organization 3 Literature Review 4 References 48 EVALUATION OF DIFFERENT ORGANIC SOLVENTS ON THE EXTRACTION EFFICIENCY OF CAPSAICINOIDS IN HOT SALSAS 60 Abstract 60 Introduction 61 Materials and Methods 63 Results and Discussion 67 Conclusions 76 References 77 EVALUATION OF COMPOSITION, AROMA, AND PUNGENCY IN COMMERCIAL SERRANO PEPPERS (CAPSICUM ANNUUM) AT THREE MATURITY STAGES: GREEN, YELLOW, AND RED 91 Abstract 91 Introduction 91 Materials and Methods 95 Results and Discussion 103 Conclusions 109 References 110 THERMAL DEGRADATION OF CAPSAICIN IN DIFFERENT MATRIXES UNDER CONVENTIONAL AND MICROWAVE HEATING 124 Abstract 124 Introduction 124 Materials and Methods 127 V Results and Discussion 134 Conclusions 142 References 142 GENERAL CONCLUSIONS 154 Conclusions 154 Recommendations 157 ACKNOWLEDGMENTS 160 vi ABSTRACT The rapid increase and consumption of ethnic foods has motivated the search for improved methods to evaluate the quality and pungent characteristics of capsicum products. In addition, little information is available about pungenc/ changes during the ripening stage of capsicums, as well as changes during their heating. Accordingly, the objectives were: a) to evaluate different organic solvents on the extraction e£5cien<y of capsaicinoids in hot salsas; b) to evaluate the composition, aroma, and pungency in commercial Serrano peppers [Capsicum anrvuum] at three maturity stages: green, yellow, and red; and c) to evaluate the thermal degradation of capsaicin in different matrixes under conventional and microwave heating. Magnetic stirring for 10 min extracted 95% of capsaicin in Cayenne pepper compared with a 1-h Goldfish extraction using 95% ethanol. No difference was found among different solvents on the extraction efficiency of diy Cayenne pepper, but diverse results were obtained from hot salsas. Extraction efficiency was affected by texture, capsaicin content, and sample preparation. Salsas labeled as "mild", "medium", and "hot" covered a broad range of pungency levels with some of them overlapping independent of the label In Serrano peppers, the red stage contained more soluble solids. vii The sugar/acid ratio was higher for the yellow and red stages. No difference was found in titratable acidity or the capsaicin content in different maturity stages. The three stages showed differences in the electronic nose mapping. Untrained panelists were unable to identify different stages and discriminate which sample had the highest intensity in aroma. Thermal degradation of capsaicin was evaluated in different matrixes (pure capsaicin, palmitic acid, soybean oil, a mixture of palmitic acid-soybean oil, and Cayenne pepper in soybean oil) heated in conventional and microwave ovens. Degradation of pure capsaicin and capsaicin in palmitic acid during conventional heating followed a pseudo first-order reaction rate. Activation energy was calculated as 9,3 Kcal/mol. No degradation was observed during the conventional heating of capsaicin and Cayenne pepper in a soybean oil matrix. In the mixed palmitic acid-soybean oil, capsaicin degradation was observed at high concentrations of palmitic acid. No degradation was detected in any matrix during microwave heating. 1 GENERAL INTRODUCTION Introdnction The production and consumption of capsicums, chiles, or hot peppers [Capsicum armuum spp.) has increased tremendously during the last 6 years in the U.S. Two reasons exist for this: consumers are adapting to new types of low-calorie diets, where spices are added to overcome the loss of flavor because of the reduction in fat content. The other reason is related to the success of new ethnic cuisines, like Asian or Mexican. The important characteristic of these foods is the spicy notes and, as in Mexican foods, the hotness or pungency. Another important trend in the U.S. is the fact that many people spend less time cooking their own meals. This has promoted the development of ready-to-cook products. With 95% of the households having a microwave oven, the trend is to design products with a dual- cooking characteristic: they can be cooked in either a conventional oven or a microwave oven. Many studies have been made to evaluate changes in food flavors due to microwave or conventional heating. However, information about the effects of these processes on the compounds responsible for the pungency in capsicums is very limited. In fact, no previous reports exist about the effect of microwave heating on these compounds, called capsaicinoids. 2 The initial goal of this work was to evaluate the effect of conventional and microwave cooking on capsaicinoids. However, soon we realized that capsicums and their products, in most of the cases, present a great variability in pungency levels. No precise data has been reported about how the variety and maturation stage, to cite some examples, affect the content of capsaicinoids. Besides this, no general agreement exits about how to extract these compounds for further analysis. Numerous authors have reported different methodologies for this extraction, with very variable results. This information is, at present, very important for the food industries who are developing capsicum products. A precise quantification of the pungency is vital to keep good quality control practices, as weU as to produce an homogeneous product which could satisfy the consumer demand. The scientific literature has reported very little information