Dairy Science and Technology Handbook Principles and Properties Y K Hui EDITOR VCH Dairy Science and Technology Handbook Product Manufacturing Y H Hui EDITOR VCH Dairy Science and Technology Handbook Applications Science, Technology, and Engineering Y K Hui EDITOR VCH Dr Y H Hui 3006 4 S " Street Eureka, California 95501 U.S.A A NOTC TO THE READER: This book has been electronically reproduced from digital information stored at John Wiley & Sons, Inc We are pleased that the use of this new technology will enable us to keep works of enduring scholarly value in print as long as there is a reasonable demand for them The content of this book is identical to previous printings Copyright O 1993 by Wiley-VCH, Inc Originally published as ISBN -56081 -078-5 No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 and 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 750-4744 Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 605 Third Avenue, New York, NY 10158-0012 (212) 850-6011, fax (212) 850-6008, e-mail PERMREQ@WILEY.COM for ordering, call 1-800-CALL-WILEY Printed in the United States of America 10 Library of Congress Cataloging-in-Publication Data Dairy science and technology handbook / editor, Y.H Hui p cm Includes bibliographical references and index ISBN 1-56081-078-5 Dairy processing Dairy products I Hui, Y H (Yiu H.) SF250.5.D35 1992 637—dc20 92-30191 PREFACE Although there are many professional reference books on the science and technology of processing dairy products, this 3-volume set is unique in its coverage (topics selected, emphasis, and latest development) and its authors (experts with diversified background and experience) Volume I discusses four important properties and applications of milk and dairy ingredients: chemistry and physics, analyses, sensory evaluation, and protein Each chapter is not a comprehensive treatment of the subject, since more than one reference book has been written on each of the four disciplines Rather, each chapter discusses the basic information in reasonable details that are supplemented by new research data and advances This assures that each chapter contributes new information not available in many reference books already published Volume II discusses the manufacture technology for yogurt, ice cream, cheese, and dry and concentrated dairy products The direction of each chapter is carefully designed to provide two types of information Each chapter details the currently accepted procedures of manufacturing the product and then explores new advances in technology and their potential impact on the processing of such products in the future The fifth chapter in this volume discusses microbiology and associated health hazards for dairy products The goal of this chapter is obvious, since there are so much new information on this topic in the last few years The authors have done an excellent job in reviewing available data on this highly visible field Volume III is unique because it covers five topics not commonly found in professional reference books for dairy manufacture: quality assurance, biotechnology, computer application, equipment and supplies, and processing plant designs The length of each chapter is limited by the size of the book As a result, I assume full responsibility for any missing details since I assigned a fixed length to each chapter The appendix to Volume I alphabetically lists products and services in the dairy industry Under each product or service, the appendix describes the names of companies that provide those products and services In Volume III, the appendix provides information for each company listed in Volume I This includes contact data and the types of products and services for each company The appendixes for Volumes I and III are not repeated in Volume II in order to assure a reasonable price for the books As for the expertise of the authors, you are the best judge since most of them are known among scientists, technologists, and engineers in the dairy discipline This three-volume set is a reference book and will benefit dairy professionals in government, industry, and academia The information is useful to individuals engaged in research, manufacturing, and teaching In general, the texts form an excellent background source for professionals who just enter the field For expert dairy professionals, these books serve as a subject review as well as a summary of what is new Any chapter in the three volumes can be used as a supplement material for a class teaching a specific topic in or an overview of the science and technology of processing diary products Y.H Hui October 1992 Contributors Genevieve L Christen, Department of Food Science and Technology, University of Tennessee, Knoxville, TN 37901-1071, U.S.A H D Goff, Department of Food Science, University of Guelph, Guelph, Ontario NlG 2Wl, Canada A R Hill, Department of Food Science, University of Guelph, Guelph, Ontario NlG 2Wl, Canada Lynn V Ogden, Department of Food Science and Nutrition, Brigham Young University, Provo, UT 84602, U.S.A Paul Paquin, Department of Food Science and Technology, University of Laval, Quebec, Province of Quebec, GlK 7P4, Canada Olivier Robin, Department of Food Science and Technology, University of Laval, Quebec, Province of Quebec, GlK 7P4, Canada Sylvie Turgeon, Department of Food Science and Technology, University of Laval, Quebec, Province of Quebec, GlK 7P4, Canada Contributors Marijana Caric, Faculty of Technology, University of Novi Sad, 2100 Novi Sad, Bulevar, Yugoslavia Ramesh C Chandan, James Ford Bell Technical Center, General Mills, Inc., 9000 Plymouth Avenue North, Minneapolis, MN 55427, U.S.A Maribeth A Cousin, Department of Food Science, Purdue University, Lafayette, IN 47906, U.S.A Rafael Jimenez-Flores, Agricultural Bioprocessing Laboratory, University of Illinois, Urbana, IL 61801-4726, U.S.A Norman J Klipfel, Baskin-Robbins International Company, Glendale, CA, U.S.A K Rajinder Nath, Kraft General Foods, 801 Waukegan Road, Glenview, IL 60025, U.S.A Khem Shahani, Department of Food Science and Technology, Food Industry Complex, University of Nebraska, Lincoln, NE 68583-0919, U.S.A Joseph Tobias, Agricultural Bioprocessing Laboratory University of Illinois, Urbana, IL 61801-4726, U.S.A P.C Vasavada, Department of Animal and Food Science, University of Wisconsin, River Falls, WI 54022 Contributors Jeffrey R Broadbent, Department of Nutrition and Food Science, Utah State University, Logan, UT 84322-8100, U.S.A Vance Caudill, Lockwood Greene Engineers, Inc., Spartanburg, SC 29304, U.S.A Thomas Gilmore, Dairy and Food Industries Supply Association, 6245 Executive Boulevard Drive, Rockville, MD 20852-3938, U.S.A Jeffrey K Kondo, Marschall Products, Rhone-Poulenc, Inc., 601 Science Drive, Madison, WI 53711, U.S.A Robert L Olsen, Department of Research and Development, Schreiber Foods, Inc., Green Bay, WI 54307-9010, U.S.A Jim Shell, Consultant, Ellicott City, MD 21043, U.S.A John E Stauffer, Stauffer Technology, Pecksland Road, Greenwich, CT 06831, U.S.A Contents Preface vii Contributors (Volume 1.) ix Contributors (Volume 2.) x Contributors (Volume 3.) xi Volume Principles and Properties Chemistry and Physics 1:1 1.1 Introduction 1:2 1.2 Composition 1:5 1.2.1 Proteins 1:9 1.2.2 Lipids 1:18 1.2.3 Lactose 1:26 1.2.4 Minor Components 1:28 Structure 1:30 1.3.1 Casein Micelles 1:30 1.3.2 Fat Globules 1:41 Physical Properties 1:49 1.4.1 Density 1:49 1.4.2 Viscosity 1:50 1.4.3 Freezing Point 1:52 1.3 1.4 This page has been reformatted by Knovel to provide easier navigation v 36 Scott, P M 1990 Natural poisons In K Helrich (ed.), Official Methods of Analysis, 15th edit., Chapter 49 Association of Official Analytical Chemists, Arlington, VA 37 Stubblefield, R D., and W F Kwolek 1986 Rapid liquid chromatographic determination of aflatoxins M1 and M2 in artificially contaminated fluid milks: collaborative study J Assoc Off Anal Chem 69:880-885 38 Park, D L., B M Miller, S Neshein, M W Trucksess, A Vekich, B Bidigare, J L McVey, and L H Brown 1989 Visual and semiquantitative spectrophotometric ELISA screening method for aflatoxin B1 in corn and peanut products: followup collaborative study J Assoc Off Anal Chem 72:638-643 39 AOAC 1990 Changes in Official Methods of Analysis of the Association of Official Analytical Chemists, First Supplement, 1990, to the 15th edit Association of Official Analytical Chemists, Arlington, VA 40 EPA 1969 EPA Compendium of Registered Pesticides U.S Government Printing Office, Washington, D.C 41 FDA 1990 Pesticide Analytical Manual U.S Dept of Health and Human Services, Washington, D.C 42 Sawyer, L D., B M McMahon, W H Newsome, and G A Parker 1990 Pesticide and industrial chemical residues In K Helrich (ed.), Official Methods of Analysis, 15th edit., Chapter 10 Association of Official Analytical Chemists, Arlington, VA 43 Hinz, C W., G L Hein, S Hinckley, J Althaus, and H Bengsch 1992 Methods to detect abnormal milk In R T Marshall (ed.), Standard Methods for the Examination of Dairy Products, 16th edit., Chapter 11 American Public Health Association, Washington, D.C 44 Marshall, R T., and J E Edmondson 1962 Value of California mastitis test records to the practioner JAVMA 140:45-49 45 Okigbo, L M., M A Shelaih, G H Richardson, C A Ernstrom, R J Brown, and E L Tippetts 1984 Portable conductivity meter for detecting abnormal milk / Dairy Sci 67:1510-1516 46 Sheldrake, R F., G D McGregor, and R J T Hoare 1983 Somatic cell count, electrical conductivity, and serum albumin concentration for detecting bovine mastitis / Dairy ScL 66:548-555 47 Packard, V S., Jr., S Tatini, R Fugua, J Heady, and C Gilman 1992 Direct microscopic methods for bacteria or somatic cells In R T Marshall (ed.), Standard Methods for the Examination of Dairy Products, 16th edit., Chapter 10 American Public Health Association, Washington, D.C 48 Pettipher, G L., and U M Rodrigues 1980 Rapid membrane filtration epifluorescent microscopic technique for the direct enumeration of somatic cells in fresh and formalin-preserved milk / Dairy Res 48:239-246 49 Pettipher, G L., and U M Rodrigues 1983 Semi-automated counting of bacteria and somatic cells in milk using epifluorescence microscopy and television image analysis Appl Environ Microbiol 53:323-329 50 Houghtby, G A., L J Maturin, and E K Koenig 1992 Microbiological count methods In R T Marshall, (ed.), Standard Methods for the Examination of Dairy Products, 16th edit., Chapter American Public Health Association, Washington, D.C 51 U.S Dept of Health and Human Services 1980 Grade A Pasteurized Milk Ordinance, no 017-001-00419-7 U.S Government Printing Office, Washington, D.C 52 Byrne, R D., Jr., J R Bishop, and J W Boling 1989 Estimation of potential shelf-life of pasteurized fluid milk utilizing a selective preliminary incubation J Food Prot 52:805-807 53 Peeler, J T., J E Gilchrist, C B Donnelly, and J E Campbell 1977 A collaborative study of the spiral plate method for examining milk samples / Food Prot 40:462-464 54 Andrews, W H., and J Messer 1990 Microbiological methods In K Helrich (ed.), Official Methods Of Analysis, 15th edit., Chapter 17 Association of Official Analytical Chemists, Arlington, VA 55 Ginn, R E., V S Packard, and T L Fox 1984 Evaluation of the 3M dry medium culture plate (Petrifilm® SM) method for determining numbers of bacteria in raw milk / Food Prot 47:753-755 56 Ginn, R E., V S Packard, and T L Fox 19S6 Enumeration of total bacteria and conforms in milk by dry rehydratable film methods: collaborative study / Assoc Off Anal Chem 69:527-531 57 Firstenberg-Eden, R A., and M K Tricarico 1983 Impedimetric determination of total mesophilic and psychrotrophic counts in raw milk J Food Sci 48:1750-1754 58 Firstenberg-Eden, R A 1984 Collaborative study of the impedance method for examining raw milk samples / Food Prot 47:707-712 59 Frank J F., G L Christen, and L B Bullerman 1992 Tests for groups of microorganisms In R T Marshall (ed.), Standard Methods for the Examination of Dairy Products, 16th edit., Chapter American Public Health Association, Washington, D.C 60 Entis, P 1986 Hydrophobic grid membrane filter method for aerobic plate count in foods: collaborative study / Assoc Off Anal Chem 69:671-676 61 Entis, P., and P Boleszczuk 1986 Use of Fast Green FCF with tryptic soy agar for aerobic plate count by the hydrophobic grid membrane filter J Food Prot 49:278-279 62 Roth, J N 1988 Temperature-independent pectin gel method for aerobic plate count in dairy and nondairy food products: collaborative study J Assoc Off Anal Chem 71:343-349 63 Richardson, G H., R Grappin, and T C Yuan 1988 A reflectance colorimeter instrument for measurement of microbial and enzymatic activities in milk and dairy products / Food Prot 51:778-785 64 Zmarticki, S., T C Yuan, and G H Richardson 1991 Improved estimations of total and psychrotrophic microflora in raw milk using reflectance colorimetry / Food Safety 11:189-196 65 Christen, G L., P M Davidson, J S McAllister, and L A Roth 1992 Coliform and other indicator bacteria In R T Marshall (ed.), Standard Methods for the Examination of Dairy Products, 16th edit., Chapter American Public Health Association: Washington, D.C 66 Roth, L A., M E Stiles, and L F L Clegg 1973 Reliability of selective media for the enumeration and estimation of Escherichia coli Can Inst Food Sci Technol J 6:230-234 67 Mayou, J 1976 MPN—most probable number In M L Speck (ed.), Compendium of Methods for the Microbiological Examination of Foods, 2nd edit., Chapter American Public Health Association: Washington, D.C 68 McCrady, M H 1915 The numerical interpretations of fermentation-tube results / Infect Dis 17:183-212 69 Ginn, R E., V S Packard, and T L Fox 1986 Enumeration of total bacteria and coliforms in milk by dry rehydratable film methods: collaborative study J Assoc Off Anal Chem 69:527-531 70 Nelson, C L., T L Fox, and F F Busta 1984 Evaluation of dry medium film (Petrifilm VRB) for coliform enumeration J Food Prot 47:520-525 71 Roth, J N., and G L Bontrager 1989 Temperature-independent pectin gel method for coliform determination in dairy products: collaborative study / Assoc Off Anal Chem 72:298-302 72 Firstenberg-Eden, R., M L Van Sise, J Zindulis, and P Kahn 1984 Impedimetric estimation of coliforms in dairy products / Food ScL 49:1449-1452 73 Marshall, R T 1992 Media In R T Marshall (ed.), Standard Methods for the Examination of Dairy Products, 16th edit., Chapter American Public Health Association, Washington, D.C 74 Entis, P 1989 Hydrophobic grid membrane filter/MUG method for total coliform and Escherichia coli enumeration in foods: collaborative study / Assoc Off Anal Chem 72:936-950 75 Feng, P C S., and P A Hartman 1982 Fluorogenic assays for immediate confirmation of Escherichia coli Appl Environ Microbiol 43:1320-1329 76 Moberg, L J 1985 Fluorogenic assay for rapid detection of Escherichia coli Appl Environ Microbiol 50:1383-1387 77 Oehlrich, H K., and R C McKellar 1983 Evaluation of an 18°C/45-hour plate count technique for the enumeration of psychrotrophic bacteria in raw and pasteurized milk J Food Prot 46:528529 78 Griffiths, M W., J D Phillips, and D D Muir 1980 Rapid plate counting techniques for enumeration of psychrotrophic bacteria in pasteurized double cream / Soc Dairy Technol 33:8-10 79 International Dairy Federation 1967 Standard method for the count of lipolytic organisms FlLIDF 41: 1966 80 Smith, J L., and J L Alford 1984 Lipolytic microorganisms In M L Speck (ed.), Compendium of Methods for the Microbiological Examination of Foods, 2nd edit., Chapter 11 American Public Health Association, Washington, D.C 81 Henson, O E., P A Hall, R E Arends, E A Arnold, Jr., R M Knecht, C A Johnson, D J Pusch, and M G Johnson 1982 Comparison of four media for the enumeration of fungi in dairy products—a collaborative study J Food ScL 47:930-932 82 Mikolajcik, E M., and N T Simon 1978 Heat resistant psychrotrophic bacteria in raw milk and their growth at 7°C / Food Prot 41:93-95 83 Schlech, W F., Ill, P M Lavigne, R A Bortolussi, A C Allen, E V Haldane, A J Wort, A W Hightower, S E Johnson, S H King, E S Nicholls, and C V Broome 1983 Epidemic listeriosis—evidence for transmission by food N Engl J Med 308:203-206 84 Wolcott, M J 1991 DNA-based rapid methods for the detection of foodborne pathogens / Food Prot 54:387-401 85 Lovett, J., and A D Hitchins 1989 Listeria isolation In R B Read, Jr (ed.), Bacteriological Analytical Manual, 6th edit., Chapter 29 Association of Official Analytical Chemists, Arlington, VA Supplement, 2nd printing 86 FDA 1990 Fed Regist 55:38953-38954 87 Mattingly, J A., B T Butman, M C Plank, and R J Durham 1988 Rapid monoclonal antibodybased enzyme-linked immunosorbent assay for detection of Listeria in food products / Assoc Off Anal Chem 71:679-681 88 King, W., S Raposa, J Warshaw, A Johnson, D Halbert, and J D Klinger 1989 A new colonmetric nucleic acid hybridization assay for Listeria in foods Int J Food Microbiol 8:225-232 89 Peterkin, P L, E S Idziak, and A N Sharpe 1989 Screening DNA probes using the hydrophobic grid-membrane filter Food Microbiol 6:281-284 90 Bennett, R W 1984 Staphylococcus aureus In R B Read, Jr (ed.), Bacteriological Analytical Manual, 6th edit., Chapter 14 Association of Official Analytical Chemists, Arlington, VA 91 Bergdoll, M S 1990 Analytical methods for Staphylococus aureus Intl J Food Microbiol 10:91-100 92 Symposium of the EFT Food Microbiology Division (1985) 44th Annual Meeting Recent developments in the detection of Salmonella in foods Food Technol 39:75-108 93 Andrews, W H., P L Poelma, and C R Wilson 1984 Isolation and identification of Salmonella species In R B Read, Jr (ed.), Bacteriological Analytical Manual, 6th edit., Chapter Association of Official Analytical Chemists, Arlington, VA 94 Fantasia, L D., J P Schrade, J F Yager, and D Debler 1975 Fluorescent antibody method for the detection of Salmonella: development, evaluation, and collaborative study J Assoc Off Anal Chem 58:828-844 95 Entis, P 1985 Rapid hydrophobic grid membrane filter method for Salmonella detection in selected foods: collaborative study / Assoc Off Anal Chem 68:555-564 96 Flowers, R S., K Eckner, D A Gabis, B J Robison, J A Mattingly, and J H Silliker 1986 Enzyme immunoassay for detection of Salmonella in foods: collaborative study / Assoc Off Anal Chem 69:786-798 97 Flowers, R S., M J Klatt, B J Robison, J A Mattingly, D A Gabis, and J H Silliker 1987 Enzyme immunoassay for detection of Salmonella in low-moisture foods: collaborative study J Assoc Off Anal Chem 70:530-535 98 Curiale, M S., M J Klatt, B J Robison, and L T Beck 1990 Comparison of colorimetric monoclonal enzyme immunoassay screening methods for detection of Salmonella in foods J Assoc Off Anal Chem 73:43-50 99 Flowers, R S., M J Klatt, and S L Keelan 1988 Visual immunoassay for detection of Salmonella in foods: collaborative study / Assoc Off Anal Chem 71:973-980 100 Flowers, R S., M J Klatt, S L Keelan, B Swaninathan, W D Gehle, and H E Chandonnet 1989 Fluorescent enzyme immunoassay for rapid screening of Salmonella in foods: collaborative study J Assoc Off Anal Chem 72:318-325 101 Flowers, R S., M J Klatt, M A Mozola, M S Curiale, D A Gabis, and J H Silliker 1987 DNA hybridization assay for detection of Salmonella in foods: collaborative study J Assoc Off Anal Chem 70:521-535 102 Curiale, M S., M J Klatt, and M A Mozola 1990 Colorimetric deoxyribonucleic acid hybridization assay for rapid screening of Salmonella in foods: collaborative study J Assoc Off Anal Chem 73:248-256 103 Kay, H D., and W R Graham, Jr 1933 The effect of heat on milk phosphatase A simple method for distinguishing raw from pasteurized milk, raw from pasteurized cream, and butter made from raw cream from that made from pasteurized cream J Dairy Res 5:63-74 104 Murthy, G K., D H Kleyn, and T Richardson 1992 Alkaline phosphatase methods In R T Marshall (ed.), Standard Methods for the Examination of Dairy Products, 16th edit., Chapter 14 American Public Health Association, Washington, D.C 105 Sanders, G P., and O S Sager 1946 Modification of the phosphatase test as applied to Cheddar cheese and application of the test to fluid milk / Dairy Sci 29:737-749 106 Sanders, G P., and O S Sager 1947 Phosphatase test of various dairy products / Dairy ScL 30:909-920 107 Sanders, G P 1948 Report on the phosphatase test in pasteurization of dairy products / Assoc Off Anal Chem 31:306-327 108 Scharer, H 1953 Scharer modified phosphatase methods / Milk Food Technol 16:86-88 109 Kleyn, D H., and S H C Lin 1968 Collaborative study of a new alkaline phosphatase assay system for milk / Assoc Off Anal Chem 51:802-807 110 Rocco, R M 1990 Fluorometric analysis of alkaline phosphatase in fluid dairy products / Food /Vor 53:588-591, 630 111 Rocco, R M 1990 Fluorometric determination of alkaline phosphatase in fluid dairy products: collaborative study J Assoc Off Anal Chem 73:842-849 112 Stone, C B 1935 Report on cheese J Assoc Off Anal Chem 18:401-402 113 Stone, C B 1937 Report on cheese / Assoc Off Anal Chem 20:339-341 114 Poortvliet, L J., and W Horwitz 1982 Determination of chloride concentration in cheese: collaborative study J Assoc Off Anal Chem 65:1350-1356 115 Horwitz, W (ed.) Official Methods of Analysis, 13th edit Association of Official Analytical Chemists, Washington, D.C 116 Fazio, T 1990 Food additives: direct In K Helrich (ed.), Official Methods of Analysis, 15th edit., Chapter 47 Association of Official Analytical Chemists, Arlington, VA CHAPTER Sensory Evaluation of Dairy Products Lynn V Ogden 3.1 The Senses, 158 3.1.1 Introduction, 158 3.1.2 Taste, 159 3.1.3 Smell, 162 3.1.4 Sight, 163 3.1.5 Hearing, 165 3.1.6 Touch, 166 3.2 Sensory Evaluation Techniques, 166 3.2.1 Introduction, 166 3.2.2 Affective Testing, 168 3.2.3 Discrimination Testing, 170 3.2.4 Descriptive Analysis, 171 3.3 Application of Sensory Analysis to Dairy Products, 174 3.3.1 The Philosophy of Judging of Dairy Products, 175 3.4 Descriptive Sensory Defects of Dairy Products, 175 3.4.1 Fluid Milk and Cream, 175 3.4.2 Cottage Cheese, 185 3.4.3 Butter, 198 3.4.4 Ice Cream and Related Products, 214 3.4.5 Cheese, 229 3.4.6 Cultured Products, 243 3.4.7 Yogurt, 254 3.4.8 Dry Milk, 267 3.5 References, 274 3.1 The Senses 3.1.1 Introduction Human senses are classified into five primary modalities: sight, hearing, touch smell, and taste.1'2 These have been further subclassified to include temperature sensation, pain, hunger, thirst, fatigue, balance, loudness, pitch, hue, brightness, and contrast to name a few A total of 22 subdivisions of the senses are generally recognized.3 Specialized organs on and in the human body respond to stimuli and send messages about the stimuli via the central nervous system to specialized areas of the brain The retina in the eye with its rods and cones is the visual receptor, the taste buds in the tongue are the taste receptors, and the olfactory tissue at the top of the nasal cavity detects smells The organ of Corti in the ear is the hearing receptor, and the nerve network that branches into human tissue is responsible for the sense of touch.4 It is by these senses that what we know about our environment has been received into our consciousness.5 The term modality is a more technically precise term for sense A group of impressions detected by one organ combine to form a sense The sense of smell, for example, is a modality Dudel classifies not only the five senses as modalities but also the subsenses temperature, vibration, pain, equilibrium, thirst, hunger, shortness of breath, and visceral sensation within each modality.4 The subsenses are known as qualities Vision for example has the qualities of hue and brightness, while taste has the qualities of sweet, sour, salty, and bitter The term stimuli refers to environmental, chemical, or physiological factors that elicit sensory impression of certain qualities.4 A combination of sensory impressions is integrated into a sensation Interpretation of those sensations with respect to experience is perception For example, judgment as to the ideality of the intensity of a quality in a particular setting is a perception.5 Two products may have an equal intensity of the quality sweetness but one product, such as bread, will be perceived as too sweet whereas a cake will be perceived as not sweet enough In analyzing human response, scientists have distinguished between objective and subjective physiology Responses of the nervous system to a stimulus are objective sensory physiology whereas perceptions and expressions of those perceptions are subjective sensory information.4 Sensory analysis of foods involves the use of statistics to treat data obtained from those subjective judgments Quantitative relationships have been developed relating objective and subjective responses.4 As the intensity of a stimulus increases various types of threshold values can be detected objectively and subjectively These have been valuable tools in establishing the relationship between the magnitude of a stimulus and sensations perceived The amount of stimulus that is required to perceive sensation is the detection threshold, stimulus threshold, or absolute threshold designated as RL.3 In objective measurements, the amount of stimulus needed to achieve this threshold is the reference unit Stimulus levels for other degrees of sensation are expressed as multiples of that.4 Above the absolute threshold, the difference threshold can be determined It is the stimulus difference necessary to produce a change in sensation and is often desig- Taste Pore Epithet Microvilti Sensory cells Synapse Perigemmal cell Basal cell Supporting cell Neural afferencies id Figure 3.1 A human taste bud and its structure and innervation The microvilli of the sensory cells protrude into a fluid-filled space in the taste pore Only two afferent fibers are drawn, while actually about 50 fibers branch within just one taste bud, which has its cells (about 40 to 70) assembled like the slices of an orange (Reproduced with permission from ref 7.) nated as DL The minimum amount of stimulus that results in correct recognition of the quality of the stimulus is the recognition threshold The magnitude of stimulus above which increases in intensity are not detected is the terminal threshold.3 The subjective measurements are the verbal or written information obtained from the taster whereas the objective measurements are obtained by measuring the frequency of action potentials of neurons The RL is the weakest stimulus intensity that results in a change in frequency of action potentials and the DL is amount of stimulus change that produces a frequency change of the action potentials of a neuron.6 Taste and smell are chemical senses in that the organs that sense taste and smell respond to chemical stimuli Sight, hearing, and touch are physical senses responding to physical stimulation such as electromagnetic radiation, sound waves, and contact or pressure 3.1.2 Taste Taste receptors are flower-bud-shaped groups of 30 to 70 sensory cells at different stages of maturity plus basal and supporting cells (Fig 3.1) located on moist surfaces in the oral cavity and pharynx A fluid-filled pore is lined with microvilli that are attached to the ends of the sensory cells Each of the active sensory cells in the taste bud have microvilli that are exposed to the pore The cells of the taste bud are Papillae foliataePap fili formeP s ap vallataPap fungifor mis Taste budsVallatedRinsing glandsTaste Striated (vonEBNERI nerves muscles ditch Figure 3.2 Taste papillae on the human tongue from surface and sectioned view (Reproduced with permission from ref 9.) innervated with about 50 afferent nerve fibers.7'8 Most of these taste buds are on the tongue, usually on the surface of or in the folds around papillae (nipplelike protrusions) (Fig 3.2) There are four types of papillae The filiform papillae are most numerous, with about 1000 on the surface of the tongue No taste buds are associated with them About to 14 vallate papillae each about to mm in diameter are located in a V-shaped line between the anterior surface and the base of the tongue (Fig 3.3) As many as 200 taste buds are located in the vallated ditch around each papillae About a hundred fungiform papillae, mm high and 0.3 to mm in diameter, are located over the surface of the tongue except for an area in the center Fungiform papillae may have several taste buds on their surface but half of the fungiform papillae have no taste buds associated with them Foliate papillae are located on the side edges of the tongue Each person has 15 to 20 of these papillae with about 10 taste buds each (Table 3.1) 10 A few taste buds not associated with papillae are located on the soft palate, pharynx, and larynx embedded in the mucous membrane.11 The four qualities that can be sensed by the taste receptors are sweet, sour, salt, and bitter.5 Different areas of the tongue vary in sensitivity to these qualities Bitter is best sensed on the back of the tongue, the sides of the tongue are most sensitive to the sour taste, and sweet and salty are best sensed on the tip of the tongue (Fig INNERVATED BY: N lingualis (tngeminus N Y Chorda tympani.N.Ml v SWEET SALTY fungiform papillae SOUR filiform papillae BITTER foliate papillae vallate papillae "Tonsilla lingualis" I= bottom or base of the tongue I N.glossopharyng.( N.IX) N vagus ( N X N laryng sup.) Figure 3 Scheme of the tongue surface showing the distribution of the taste papillae, the innervation, and the areas of maximal sensitivity for each taste quality (Reproduced with permission from ref 10.) Table 3.1 HUMAN TONGUE PAPILLAE AND THEIR TASTE BUDS IN ADULTS Circumvallate (P vallatae) Foliate Number of Papillae Taste Buds per Papilla Taste Buds in AU Papillae 8-12 (7-14) 15-20 100-200 1000-1500 =-10 150-200 0-4 300-400 0 (P.foliatae) Fungiform -100 (P.fungiformes) Filiform (P filiformes) =-1000 Reproduced with permission from ref 10 THE SENSE OF SMELL Olfactory nerve Trigeminal nerve Trigeminal nerve Figure 3.4 A representation of the lateral wall of the human nasal cavity showing the nasal turbinates and distributions of olfactory and trigeminal nerves (Reproduced with permission from ref 13.) 3.3) Taste receptors are able to sense multiple qualities but they are somewhat specialized in that they respond better to some qualities than others.10 Some individuals are taste-blind to some qualities Blakesly and Fox demonstrated that approximately 30% of subjects are blind to the bitter taste of phenylthiocarbamide (PTC) and the lack of taste acuity for that quality is an inherited trait.12 They also demonstrated taste-blindness for other substances 3.1.3 Smell The sense of smell in man results from stimulation of chemoreceptors on the olfactory and trigeminal nerve systems The olfactory epithelium is located in the dorsoposterior or upper rear of the nasal cavity (Fig 3.4) and is yellow in color as opposed to the pink color of the respiratory epithelium The olfactory epithelium is covered with cilia that extend into the mucous layer Four types of cells make up the tissue: receptor neurons, microvillar cells, supporting cells, and basal cells (Fig 3.5) A ciliated protrusion of the receptor neuron at the mucosal surface is called the olfactory knob.15 The microvillar cells also appear to be sensory neurons with microvilli extending into the mucosal layer.14 The basal cells give rise to new receptor cells Bowman's glands below the olfactory epithelium secrete mucous through ducts to the mucosal layer The supporting cells also secrete fluid.16 Volatile odorant molecules smaller than 400 MW dissolve in the mucus before reacting with the receptor Cilia Mlcrovllli Olfactory knob Mlcrovillar ceil Olfactory receptor neuron Supporting cell Basal cell Lamina Axon propria Figure 3.5 A representation of the structure of the human olfactory epithelium (Reproduced with permission from ref 14.) cells.17'18 The axons of the olfactory receptor neurons from each nasal cavity travel through the cribriform plate to the olfactory bulb in the brain.19-20 This olfactory system is very sensitive, responding to very low concentrations of some chemicals A typical threshold for allyl mercaptan is 107 molecules per milliliter It is also very discriminating A trained perfumer can distinguish 150 to 200 odor qualities.21 Because the olfactory tissues are out of the mainstream of nasal airflow, odorants reach them by turbulent eddies that are maximized by "sniffing." Odor sensations are not noticed when the breath is held To enhance the sense of smell, a subject must " s n i f f air that has been in contact with the food It also helps to move air out through the nose while food is in the mouth.5 The trigeminal nerves respond to chemical irritants such as ammonia, ginger, horseradish, onion, chili peppers, and menthol Sensations experienced in the mucosa of the mouth and nose include coolness, heat, and pungency Usually the concentrations required are much higher than those required by the olfactory system, but it is difficult for subjects to separate trigeminal sensations from olfactory and gustatory ones 3.1.4 Sight Vision is an extremely important component of sensory perception of foods Attractive appearance of dairy products enhances acceptability Colors are almost inseparably associated with flavors Coloring some flavors atypically makes recognition difficult The eye is a complex instrument complete with a clear cornea to protect the iris and lens, a clear liquid called the aqueous humor between the cornea and the lens, an adjustable lens that focuses an image on the retina at the back of the orb, an iris Optic array Fovea Blind spot Pupil Cornea Lens Iris Optic nerve Retina Retinal image Rod Retina Cone Optic arr^y (distribution of light ^i the eye): the proximal stimulus distribution Light Connective cells Figure 3.6 The eye, showing the lens, retina, blind spot, and optic nerve The fovea is a small region, central in the retina, that is highly sensitive to detail and consists entirely of cones (Reproduced with permission from ref 22.) to adjust the amount of light falling on the retina, and a clear liquid medium called the vitreous humor through which the light passes from the lens to the retina (Fig 3.6) The retina, which covers much of the back of the eye, contains rods which detect 400 to 700 nm light and cones which are sensitive to the wavelength of light enabling us to see color When the rhodopsin pigment in the rods is exposed to light, it produces a nerve impulse as it is chemically changed Color vision of the cones is explained by the Young-Von Helholtz theory that three types of receptors are present each of which is sensitive to one of the primary colors Stimulation of the three receptors at different relative intensities results in color sensation Impulses from the rods and cones travel through the optic nerve to the brain where the sensation is perceived and interpreted.22"24 Cone vision is trichromic and the color of any light can be matched by mixing red, green, and blue monochromatic primary light in a suitable blend of intensities 25 There is also an opposing mechanism in which green is opposite red, blue is opposite yellow, and black is opposite white 26 Modem colorimeters use these three coordinates to define the hue (color), value (lightness), and chroma (saturation) of the light coming into the eye from an object 27 The eye adapts to the level of light supplied by constriction or dilation of the pupil and adjustment of the sensitivity of the retina.23 It also adapts to the wavelength When the eye is exposed to bright monochromatic light, sensitivity to that hue is suppressed and it begins to appear more dull When this occurs, a white surface will appear momentarily to be the opposite hue For example, after several seconds of exposure to bright blue it will begin to appear more dull At a glance, white will momentarily appear to be yellow Appearance of objects will be affected by the extent to which objects transmit, diffuse, or reflect light Clear materials allow light to pass through them (water) Auricle Cartilage Mastoid Ceils Malleus Semicircular Canals Incus Vestibule Vestibular N Facial N Cochlear N Internal Auditory Canal Cochlea External Auditory Canal Round Window Stapes Drum Membrane Mastoid Tip Cross Section of Eustachian Tube Figure 3.7 A semidiagrammatic drawing of the ear (Reproduced with permission from ref 29.) Colored clear materials absorb some wavelengths of light and alter color (colored gelatin dessert) Translucent materials allow the passage of light but diffuse it (fruit juices) and opaque materials reflect diffused light (milk) and may absorb some wavelengths to alter color (cheese) Some light may be reflected to the eyes without diffusion, resulting in highlights and giving a glossy appearance.79 3.1.5 Hearing A diagram of the human ear is shown in Figure 3.7 Vibrations carried through air or through the bones of the head cause the eardrum or tympanic membrane to vibrate, and the vibrations are transmitted via the small bones in the middle ear to the inner ear where the vibrations are converted to hydraulic motion in the fluid of the cochlea The spiral-shaped cochlea is divided along its length by the basilar membrane and the vestibular membrane Numerous hair cells are located along the basilar membrane The vibrations cause the basilar membrane to move as a traveling wave That motion stimulates the hair cells, causing them to send impulses to the brain The impulses travel along the auditory nerve to the brain In an adult the detectable frequency range is 30 to 15,000 Hz but the most sensitive range is 500 to 4000 Hz 30 ' 31 When crisp or crunchy foods are consumed, it is expected that the sounds that are generated will be an important factor in texture perception of that food Loudness and discontinuity of the sound have been established as the two basic criteria for distinguishing food sounds "Loud," "snap," and "crackly" were shown to be related to crispness Loudness was closely associated with crispness but not so closely associated with firmness.32 The sound is helpful but not essential to the perception of crispness Subjects had no difficulty in judging crispness when a blocking noise was used to mask the sounds and they were able to judge the crispness accurately when listening to a recording of the sounds Biting a crisp food gives auditory and tactile sensations which can both be used to judge crispness.3334 Few dairy products produce snapping or crunching noises as they are consumed so contributions of hearing to their sensory evaluation are probably minor Experienced judges can sometimes determine the number and size of eyes in Swiss cheese by tapping the outside of the cheese and the amount of free water in "leaky" butter by the "slushing" sound made as the plug is reinserted into the hole from which it was drawn.5 3.1.6 Touch A variety of types of nerve endings are responsible for the sensation of touch Figure 3.8 shows the free nerve endings in the skin, epidermis, dermis, and subcutaneous tissue They include the tactile discs, Meissner corpuscles, end bulbs of Krause, Ruffini endings, Pacinian corpuscles, and the nerve endings around the hair follicle These nerve endings are responsible for the "somesthesis" sensations we call touch, pressure, heat, cold, itching, and tickle These nerves are sensitive in the mouth, lips, and tongue, making detection of small forces and pressures easy during eating Deep pressure or "kinesthesis" is felt through the nerve fibers in the joints, tendons, and muscles They sense tension resistance and relaxation These nerves in the hand, tongue, and jaw are used to sense the pressure and tension used to manipulate, deform, rupture, and masticate food These nerves combined are very good at distinguishing particle size, crispness, hardness, elasticity, brittleness, fluid viscosity, and temperature and are significant in our sensory perception of foods.30 The trigeminal nerves which have already been covered and are so important to our taste and smell could properly be considered part of our sense of touch 3.2 Sensory Evaluation Techniques 3.2.1 Introduction For hundreds of years, the quality of dairy products has been known to be linked to feeding and milk handling practices A relationship between certain feeds and milk flavor was established early Turnips for example were known to give an "ill" flavor to butter.36 Product grades and score cards were developed Attention was drawn to sensory quality of dairy products in 1916 when a collegiate butter judging contest was initiated with nine teams participating Milk and cheddar cheese were added to the contest the next year Over the years, vanilla ice cream, cottage cheese, and [...]... navigation 1: 146 viii Contents 2.9 3 Summary 1: 148 2 .10 Future Developments 1: 148 2 .11 References 1: 149 Sensory Evaluation of Dairy Products 1: 157 3 .1 The Senses 1: 158 3 .1. 1 Introduction 1: 158 3 .1. 2 Taste 1: 159 3 .1. 3 Smell 1: 162 3 .1. 4 Sight 1: 163 3 .1. 5 Hearing 1: 165 3 .1. 6 Touch 1: 166 Sensory Evaluation Techniques 1: 166 3.2 .1. .. Hypochlorites 1: 113 2.4.7 Aflatoxins 1: 113 2.4.8 Pesticides 1: 114 Tests for Abnormal Milk 1: 115 2.5 .1 “Cow-Side” Tests 1: 115 2.5.2 Wisconsin Mastitis Test 1: 116 2.5.3 Somatic Cell Count 1: 117 Microbiological Methods 1: 120 2.6 .1 Aerobic Plate Count 1: 1 21 2.6.2 Coliform Count 1: 126 2.6.3 Tests for Specific Spoilage Bacteria 1: 1 31 2.6.4 Tests for... CHAPTER 1 Chemistry and Physics H D GoffandA R Hill 1. 1 Introduction, 2 1. 2 Composition, 5 1. 2 .1 Proteins, 9 1. 2 .1. 1 Caseins, 9 1. 2 .1. 2 Whey Proteins, 14 1. 2 .1. 3 Enzymes, 15 1. 2.2 Lipids, 18 1. 2.2 .1 Chemical Properties, 18 1. 2.2.2 Physical Properties, 19 1. 2.2.3 Lipolysis, 22 1. 2.2.4 Oxidation, 24 1. 2.3 Lactose, 26 1. 2.3 .1 Biochemical Properties, 26 1. 2.3.2 Physicochemical Properties, 26 1. 2.4 Minor... Components, 28 1. 2.4 .1 Vitamins, 28 1. 2.4.2 Minerals, 29 1. 3 Structure, 30 1. 3 .1 Casein Micelles, 30 1. 3 .1. 1 Properties, 30 1. 3 .1. 2 Stability, 35 1. 3 .1. 3 Aggregation, 38 1. 3.2 Fat Globules, 41 1.3.2 .1 Native Fat Globule Membrane, 41 1.3.2.2 Recombined Membranes, 44 1. 3.2.3 Stability, 46 1. 3.2.4 Destabilization, 48 1. 4 Physical Properties, 49 1. 4 .1 Density, 49 1. 4.2 Viscosity, 50 1. 4.3 Freezing Point, 52 1. 4.4... Transformations 2: 213 3 .10 .4 Flavor Development 2: 213 3 .11 Microbiological and Biochemical Changes in Cheddar Cheese 2: 215 3 .11 .1 Fate of Lactose 2: 215 3 .11 .2 Fate of Casein 2: 216 3 .11 .3 Microbiological Changes 2: 217 3 .11 .4 Fate of Fat 2: 218 3 .11 .5 Flavor of Cheddar Cheese 2: 219 3 .12 Microbiological and Biochemical Changes in Swiss Cheese 2: 219 3 .12 .1 Fate of Lactose... Lactose 1: 99 2.3.5 Ash 1: 1 01 2.3.6 Vitamins 1: 1 01 2.3.7 Minerals 1: 102 This page has been reformatted by Knovel to provide easier navigation Contents 2.4 2.5 2.6 2.7 Tests for Milk Quality 1: 102 2.4 .1 Titratable Acidity 1: 102 2.4.2 Added Water 1: 105 2.4.3 Sediment 1: 106 2.4.4 Antibiotics 1: 107 2.4.5 Acid Degree Value 1: 112 2.4.6 Iodine... 1. 4.4 Electrochemistry 1: 54 1. 4.5 Surface Tension 1: 56 1. 4.6 Acid-Base Equilibria 1: 57 1. 4.7 Heat Capacity and Thermal Conductivity 1: 60 Optical Properties 1: 60 1. 5 Summary 1: 61 1.6 Future Developments 1: 62 1. 7 References 1: 62 Analyses 1: 83 2 .1 1:85 1. 4.8 2 Introduction 2 .1. 1 2.2 2.3 Purpose of Analysis of Dairy Products 1: 85... 2 :14 9 2.9 .12 Defects Due to Storage of Ice Cream 2 :14 9 2.9 .13 Defects of Frozen Dessert Novelties 2 :15 0 2 .10 Plant Management 2 :15 1 2 .11 Active Areas of Research in Ice Cream 2 :15 3 2 .11 .1 Ice Cream Mix 2 :15 3 2.6 2.7 2.9.9 This page has been reformatted by Knovel to provide easier navigation xiv 3 Contents 2 .11 .2 Ice Cream Structure 2 :15 5 2 .11 .3 Processing and Freezing 2 :15 6... Introduction 1: 166 3.2.2 Affective Testing 1: 168 3.2.3 Discrimination Testing 1: 170 3.2.4 Descriptive Analysis 1: 1 71 Application of Sensory Analysis to Dairy Products 1: 174 3.2 3.3 3.3 .1 3.4 3.5 The Philosophy of Judging of Dairy Products 1: 175 Descriptive Sensory Defects of Dairy Products 1: 175 3.4 .1 Fluid Milk and Cream 1: 175 3.4.2 Cottage Cheese 1: 185 3.4.3... Ices 2 :11 7 2.4.9 Direct-Draw Shakes 2 :11 8 2.4 .10 Frozen Yogurt 2 :11 9 2.4 .11 Other Frozen Desserts 2 :11 9 2.4 .12 Nonstandardized Products 2 :12 0 Mix Processing 2 :12 1 2.5 .1 2 :12 1 2.4.4 2.5 2:92 Pasteurization This page has been reformatted by Knovel to provide easier navigation Contents xiii 2.5.2 Homogenization 2 :12 5 2.5.3 Mix Cooling and Storage 2 :12 7 Flavoring