Hydrocolloids: Practical Guides for the Food Industry PDF
Preview Hydrocolloids: Practical Guides for the Food Industry
Cover: PGA molecules courtesy of Bruno Manunza; Stable Micro Systems Ltd. TA-XT2 Texture Analyser; guar seeds and carob seeds; sandwich courtesy of the Wheat Foods Council; milk drink © 1995 PhotoDisc, Inc.; ice cream cone © 1997 Artville LLC. Library of Congress Catalog Card Number: 2004103901 International Standard Book Number: 1-891127-38-1 ©2004 by the American Association of Cereal Chemists, Inc. All rights reserved. No part of this book may be reproduced in any form, including photocopy, microfilm, information storage and retrieval system, computer database or software, or by any means, including electronic or mechanical, without written permission from the publisher. Reference in this publication to a trademark, proprietary product, or company name is intended for explicit description only and does not imply approval or recommendation of the product to the exclusion of others that may be suitable. Printed in the United States of America on acid-free paper American Association of Cereal Chemists 3340 Pilot Knob Road St. Paul, Minnesota 55121-2097, USA About the Eagan Press Handbook Series The Eagan Press Handbook series was developed for food industry practitioners. It offers a practical approach to understanding the basics of food ingredients, applications, and processes—whether the reader is a research chemist wanting practical information compiled in a single source or a purchasing agent trying to understand product specifications. The handbook series is designed to reach a broad readership; the books are not limited to a single product category but rather serve professionals in all segments of the food processing indus- try and their allied suppliers. In developing this series, Eagan Press recognized the need to fill the gap between the highly fragmented, theoretical, and often not readily available information in the scientific literature and the product-specific information available from suppliers. It enlisted experts in specific areas to contribute their expertise to the development and fruition of this series. The content of the books has been prepared in a rigorous manner, including substantial peer review and editing, and is presented in a user-friendly format with definitions of terms, examples, illustrations, and trouble-shooting tips. The result is a set of practical guides con- taining information useful to those involved in product development, production, testing, in- gredient purchasing, engineering, and marketing aspects of the food industry. 19658 inside cover corr 4/19/04 1:40 PM Page 1 19658_inside cover black Acknowledgment of Sponsors for Hydrocolloids The Eagan Press Handbook Series Eagan Press has designed this handbook series as practical guides serving the interests of the food Colorants, F. J. Francis, 1999 industry as a whole rather than the individual interests of any single company. Nonetheless, corpo- rate sponsorship has allowed these books to be more affordable for a wide audience. Dairy-Based Ingredients, Ramesh Chandan, 1997 Eagan Press thanks the following companies for their financial support of this handbook: Emulsifiers, Clyde E. Stauffer, 1999 Enzymes, Paul R. Mathewson, 1998 AEP Colloids - Division of Sarcom Inc. Gumix International, Inc. Fats and Oils, Clyde E. Stauffer, 1996 Saratoga Springs, NY Fort Lee, NJ +1.800.848.0658 +1.201.947.6300 High-Fiber Ingredients, Amy L. Nelson, 2001 www.aepcolloids.com www.gumix.com Aqualon, A Business Unit of Hercules Ingredients Solutions, Inc. Hydrocolloids, Andrew Hoefler, 2004 Incorporated Searsport, ME Wilmington, DE +1.888.548.4758 Starches, David J. Thomas and William A. Atwell, 1999 +1.800.345.0447 www.isinc.to Sweeteners: Alternative, Amy L. Nelson, 2000 www.aqualon.com Archer Daniels Midland Company Instron Sweeteners: Nutritive, Richard J. Alexander, 1998 Decatur, IL Canton, MA +1.800.553.8411 +1.800.564.8378 Wheat Flour, William Atwell, 2001 www.admworld.com www.instron.com Cargill Food & Pharma Specialties ISP Food Ingredients Cedar Rapids, IA Wayne, NJ +1.877.650.7080 +1.877.389.3083 www.cargillfoods.com www.ispcorp.com CP Kelco Noviant San Diego, CA Arnhem, The Netherlands +1.858.292.4900 +31.(0).26.365.3200 www.cpkelco.com www.noviantgroup.com Danisco USA Inc. PL Thomas & Co., Inc., Gums Division New Century, KS Morristown, NJ +1.913.764.8100 +1.973.984.0900 www.danisco.com www.plthomas.com Degussa Texturant Systems Polypro International, Inc. Atlanta, GA Minneapolis, MN +1.800.241.9485 +1.800.POLYPRO www.texturantsystems.com www.polyprointl.com Gum Technology Corp. Tate & Lyle Tucson, AZ Decatur, IL +1.800.369.4867 +1.800.526.5728 www.gumtech.com www.tlna.com Acknowledgments Eagan Press thanks the following individuals for their contributions to the preparation of this book: Ross Clark, CP Kelco US, San Diego, CA Martin Glicksman, Valley Cottage, NY Florian Ward, TIC Gums Inc., Belcamp, MD Contents 1. Introduction to Food Hydrocolloids • 1 Water “Organizing” Effects of Hydrocolloid Structure Gum Combinations Formulating with Gums 2. Hydrocolloid Sources, Processing, and Characterization • 7 Seed and Root Hydrocolloids:guar gum • locust bean gum • Tara gum • konjac flour Exudate Hydrocolloids:gum arabic • gum tragacanth • gum karaya Extract Hydrocolloids:seaweed extracts • plant and animal extracts Microbiological Hydrocolloids:xanthan gum • gellan gum Cellulose Derivative Hydrocolloids Other Derivative Hydrocolloids 3. Functions and Properties • 27 Hydrocolloid Dispersion and Hydration Thickening Agents Versus Gelling Agents:gelling agents • thickening agents Importance of the Uniformity of Substitution Compatibility of Hydrocolloid Combinations Relative Cost of Hydrocolloids 4. Testing and Rheological Measurement • 43 A Quick Lesson in Rheology Types of Rheological Measurement Devices:viscometers • gel strength mesuring devices • other rheological instruments Hydrocolloid Specifications 5. Selecting Hydrocolloids for Food Applications • 55 Improving Stability:heat stability • separation over time • undesirable crystal growth over time • syneresis • dairy products containing protein Creating and Improving Texture:thickening agents • gelling agents Improving Both Texture and Stability Improving Nutrition v 6. Dairy Products and Related Applications • 67 Frozen Desserts Cultured Milk Products Yogurt–Juice and Milk–Juice Drinks Chocolate and Flavored Milks Cheese Spreads Ready-to-Eat Milk-Based Desserts Troubleshooting 7. Processed Fruit, Confectionery, and Beverages • 77 Processed Fruit:jam, jellies, and preserves • yogurt fruit and ice cream ripples • bakery fillings Confectionery Nondairy Fruit-Flavored Beverages Troubleshooting 8. Other Food Applications • 91 Salad Dressings Tomato- and Mustard-Based Products Processed Meat Products Baked Goods Hydrocolloid-Based Fat Replacers Pancake Syrup Pet Food Water Gel Desserts Troubleshooting Glossary • 105 Index • 107 vi CHAPTER 1 Introduction to Food Hydrocolloids Hydrocolloids, or gums, are substances consisting of hydrophilic, long-chain, high molecular weight molecules, usually with colloidal In This Chapter: properties, that in water-based systems produce gels, i.e, highly vis- Water “Organizing” cous suspensions or solutions with low dry -substance content. In Effects of Hydrocolloid addition to their primary purpose of thickening and/or gelation, Structure hydrocolloids often exhibit related secondary functions, such as emulsifying, whipping, suspending, and encapsulating. They are gen- Gum Combinations erally polysaccharides, but gelatin (a protein) is included because its Formulating with Gums functionality is very similar to that of the polysaccharide-based gums. Hydrocolloids have been used since at least as far back in time as Hydrophilic—Having an affin- ancient Egypt. The exudate of a plant in the genus Acanthusfound in ity for water; readily absorbing that region was used as an adhesive in the wrapping of mummies and or dissolving in water. as a medium for water-based paints. Many hydrocolloids have been part of the human diet for several thousand years. For example, lo- Colloid—A system in which cust bean gum (LBG) was known as “Saint John’s bread” and is still finely divided particles are dis- persed within a continuous called by that name in several European countries. medium in such a way that Over time, many useful, natural plant exudates were discovered they are not filtered easily and and designated “gums,” including rubber, rosin, chicle (“chewing” do not settle rapidly. gum), and other resinous materials. Eventually, the nomenclature for these natural materials became very confused, and it has been only Polysaccharide—A carbo- during the last 50 years that an effort has been made to clarify the ter- hydrate containing several hun- minology. In this book, “gums” refers only to the water-soluble type. dred, thousand, or hundred thousand sugar units (from the The water-insoluble (but oil- or organic solvent-soluble) materials are Greek poly, meaning “many”). referred to as “resins.” “Hydrocolloid,” a contraction of hydro- philic colloid, is the more scientific name for gums. Hydrocolloids are not really colloids, because they are truly water soluble. They are polymers of colloidal size (10–1,000Å) and ex- hibit certain of the colloidal properties, such as the ability to remain suspended in water under the influence of gravity. Hydrocolloids can have linear or branched molecules (Fig. 1-1). The linear type (such as cellulose, amylose, alginates, and pectin) are the most abundant in nature and have sugar units that repeat over the entire length of the Fig. 1-1. Comparison of linear and branched hydrocolloid polymer. They usually have side units, which molecules. 1 2 / CHAPTER ONE TABLE 1-1.Two Main Methods of Classifying Food Hydrocolloids Method Hydrocolloids Raw material source Seedsa Guar, locust bean gum, tara gum Roota Konjac Exudates Gum arabic, tragacanth, gum karaya Seaweed extracts Red Agar, carrageenan Brown Sodium alginate, propylene glycol alginate Plant extracts Pectin, amylose Animal extracts Gelatinb Microbiological Xanthan gum, gellan gum, pullulan Cellulose derivatives Cellulose gum, methylcellulose, hydroxypropylcellulose, methylhydroxypropylcellulose, microcrystalline cellulose Other derivatives Propylene glycol alginate, low ester amidated pectin Structure Linear Neutral Microcrystalline cellulose, methycellulose, hydroxypropyl- cellulose, amylose, guar, locust bean gum, tara, konjac Charged Pectin and low ester pectin, alginate andpropylene glycol alginate, carrageenan, cellulose gum, agar, xanthan gum, gellan gum Branched Neutral Amylopectin Charged Gum arabic, tragacanth, karaya aThe galactomannans and glucomannans. bAlthough chemically gelatin is a protein rather than a carbohydrate, it is classified here as a hydrocolloid on the basis of its functionality and behavior in food systems. can be composed of single or multiple sugar units, or they can be as simple as carboxyl groups, sulfate groups, or a methyl ether group. Generally, these side units greatly influence the properties of the hy- drocolloid. Most hydrocolloids occur naturally, but there are also sev- eral natural hydrocolloids that have been chemically modified, such as carboxymethyl cellulose (CMC), also known as cellulose gum, and propylene glycol alginate. Throughout this book, different types of classification systems based on chemical, functional, and physical properties are mentioned. In Table 1-1, hydrocolloids are classified by source and by structure and charge characteristics. Water “Organizing” When hydrocolloids are in solution, one can visualize a cylinder of “organized” water surrounding the molecule. The water molecules are oriented with respect to the hydroxyl groups found on the indi- vidual sugar units of the hydrocolloid molecule (Fig. 1-2). The main effects of hydrocolloids result from their ability to organize water INTRODUCTION TO FOOD HYDROCOLLOIDS \ 3 Thixotropic—Describing a gel that decreases in viscosity with time while undergoing shear. Organized Water Layer Yield point—Point at which a plastic fluid under stress begins to flow. Junction zone—An area of binding of segments of mo- lecular chains produced by intermolecular attractions re- sulting from hydrogen bond- ing, hydrophobic associations, ionic cross-bridges, and/or entanglements. Hydrocolloid Molecule Syneresis—The separation of liquid from a gel; weeping. Fig. 1-2.Hydrocolloid molecules surrounded by ”organized” water. and/or form networks. Visualize a hydrocolloid molecule as looking like a long, flexible piece of yarn. Now visualize a cylinder of water surrounding the yarn, to some arbitrary distance, such that this layer of organized water of hydration actually moves around with the gum molecule. This water is organized in the sense of being associated with the long, thin gum molecule, particularly at the hydroxyl groups along the polysaccharide chain and at any of the anionic groups that are present on some gums, and moves around with the gum molecule to some extent. Increased associa- tions generally lead to increases in volume and swelling. It is helpful to divide hydrocolloids roughly into two functional categories: the thickeners and the gelling agents. Thickeners consist of individual hydrated mole- cules that exhibit little interaction with each other, ex- cept for random collisions in solution. They move about randomly, with their layer of organized water “follow- ing” them. Some gums do not merely thicken, but cross-link or otherwise form associations using various types of bonds at junction zones to form a three-dimensional network called a gel (Fig. 1-3). This forms a viscoelastic structure, often after cooling from applied heat. Some gels are ther- mally reversible; that is, the gel goes back into solution Fig. 1-3. Network structure of a gel, known with reheating. Some gels, such as low ester pectin or gel- as a fringed micelle structure. Molecules are joined at junction zones; the areas between the lan, require divalent cations, such as calcium, to form a molecules contain an aqueous solution. (Re- gel. Thixotropic gums are thought to form weak gels that printed from Whistler, R.L., and BeMiller, J.N., are broken after applied shear reaches the yield point. If the 1997, Carbohydrate Chemistry for Food Scien- junction zones expand with time, the structure contracts, tists, American Association of Cereal Chemists, squeezing out the bound water and resulting in syneresis. St. Paul, MN)
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