_MNL_13-1992.pdf

Manual on Descriptive Analysis Testing for Sensory Evaluation Robert C.Hootman,editor ASTM Manual Series:MNL 13#1916 Race Street.Philadelphia,PA 19103 Library of Congress Cataloging-in-Publication Data Manual on descriptive analysis testing for sensory evaluation/Robert C.Hootman,editor.(ASTM manual series:MNL 13)Includes bibliographical references and index.ISBN 0-8031-1756-6 1.FoodSensory evaluation.I.Hootman,Robert C.II.Series.TX546.M36 1992 664.07dc20 92-13840 CIP 1992 by American Society for Testing and Materials ASTM Publication Code Number(PCN):28-013092-36 NOTE:The Society is not responsible,as a body,for statements and opinions advanced in this publication.Printed in Baltimore,MD/IMay 1992 Foreword The Manual on Descriptive Analysis Testing for Sensory Evaluation was sponsored by Com-mittee E-18 on Sensory Evaluation.Descriptive analysis is a sensory method by which the attributes of a food or product are identified and quantified,using human subjects who have been specifically trained for this purpose.The analysis can include all parameters of the prod-uct,or it can be limited to certain aspects,for example,aroma,taste,texture,and aftertaste.Many descriptive analysis methods and method variations are currently employed by sensory professionals.This forthcoming book will only be concerned with four,which have been pub-lished and are widely used:flavor profile,quantitative descriptive analysis(QDA),Spectrum,and texture profile.An overview of each method will be presented,with examples and differ-ences among the methods and how they are used.Committee E-18 believes this manual will be unique in that these four descriptive analysis methods have never before been put together in one book.We hope it is a useful reference for sensory professionals,laboratories,and management.Contents Introduction 1 Chapter 1The Ravor Profile 5 by Patricia Keane Chapter 2Quantitative Descriptive Analysis(QDA)15 by Herbert Stone Chapter 3The Spectrum Descriptive Analysis Method 22 byAlejandra M.Munoz and Gail Vance Civille Chapter 4The Texture Profile 35 by Alejandro M.Munoz,Alina S.Szczesniak,Margery A.Einstein,and Naomi O.Schwartz Index 51 MNL13-EB/May 1992 Introduction Descriptive analysis is the sensory method by which the attributes of a food or product are identified and quantified using human subjects who have been specifically trained for this pur-pose.The analysis can include all parameters of the product,or it can be limited to certain aspects,for example,aroma,taste,texture,and aftertaste.While the principles of descriptive analysis are applied by many sensory professionals,overviews of four currently published methods will be presented.Many variations of these methods are in current use.This publi-cation will be concerned only with the following:flavor profile,quantitative descriptive anal-ysis(QDA),spectrum,and texture profile(Table 1).The following information is intended as a description of each method,not as a manual to be used for training of this type of panel.Descriptive analysis is appropriate for use when detailed information is required on indi-vidual characteristics of the product or material or both.Some examples of application of descriptive analysis are as follows:Documenting product sensory characteristics Identifying and quantifying sensory characteristics for research guidance,product main-tenance,and matching Correlating instrumental and chemical measurements with sensory responses Monitoring product quality Interpreting consumer responses In many cases this sensitive method of descriptive analysis provides information that cannot be obtained by other analytical means.For example,analysis of salt content or pH does not indicate how salty or how sour a product may taste.Nor is it usually possible to monitor subtle changes in shelf Ufe or package stability using analytical instruments.The only effective way to monitor complex changes in oxidation,rancidity,or flavor intensity,as well as the intro-duction of new attributes that so often occur with storage,is by using descriptive analysis methods.Establishing a trained panel to perform descriptive analysis is not a casual matter.This method requires that the panel be carefully trained and maintained under the supervision of a sensory professional who has training and experience in the analytical method being applied.Because of the expense(in actual dollars and personnel time)of training and maintaining a panel,as well as the possible need for capital investment of a special facility,company man-agement must provide a long-term commitment.Without such support it is almost impossible to successfully develop and maintain the panel.However,the benefits of having this important analytical method usually outweigh the disadvantages.For this reason,many companies have found the method of descriptive analysis to be an essential part of their sensory evaluation program.1 Copyright 1992 byASTM International www.astm.org DESCRIPTIVE ANALYSIS TESTING FOR SENSO