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This Brief reviews the chemistry behind the production of yoghurt through acidification of milk. It quantifies the changes in physical and chemical properties of yoghurt during fermentation with microbial organisms (such as Lactobacillus bulgaricus and Streptococcus thermophilus). It has been found that this symbiosis has an optimal development at a temperature of ca. 45°C with the transformation of lactose into lactic acid and small amounts of acetaldehyde, diacetyl and volatile acids. This Brief explains the chemical and physical results of the fermentation process, such as precipitation of proteins and the acid coagulation of milk with a clot formation in the final semi-solid mass. The Brief sheds light on the accomplishments of the fermenting organisms: they are responsible for the biochemical reactions of carbohydrate metabolism, proteolysis, lipolysis and flavour production in the process of yoghurt production. It also briefly reviews formulations and food additives used in the modern yoghurt producing industry.
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SPRINGER BRIEFS IN MOLECULAR SCIENCE CHEMISTRY OF FOODS Ettore Baglio Chemistry and Technology of Yoghurt Fermentation SpringerBriefs in Molecular Science Chemistry of Foods Series editor Salvatore Parisi, Palermo, Italy For further volumes: http://www.springer.com/series/11853 Ettore Baglio Chemistry and Technology of Yoghurt Fermentation 13 Ettore Baglio Food Technologist Catania Italy ISSN 2191-5407 ISSN 2191-5415 (electronic) ISBN 978-3-319-07376-7 ISBN 978-3-319-07377-4 (eBook) DOI 10.1007/978-3-319-07377-4 Springer Cham Heidelberg New York Dordrecht London Library of Congress Control Number: 2014940155 © The Author(s) 2014 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Contents 1 The Modern Yoghurt: Introduction to Fermentative Processes. . . . . . 1 1.1 Fermented Milks: The Peculiarity of Yoghurts . . . . . . . . . . . . . . . . . 2 1.2 Fermentation and Processes. . . . . . . . . . . . . . . . . . . . . . . . . . .