Preface

Starch is a natural, cheap, available, renewable, and biodegradable polymer produced by many plants as a source of stored energy. It is the second most abundant biomass in nature. It is found in plant leaves, stems, roots, bulbs, nuts, stalks, crop seeds, and staple crops such as rice, corn, wheat, cassava, and potato. It has wide use in the food, textiles, cosmetics, plastics, adhesives, paper, and pharmaceutical industries. For example, in the food industry starch has a wide range of applications ranging from being a thickener, gelling agent, to being a stabilizer for making snacks, meat products, and fruit juices. It is either used as an extract from the plant in which case it is called "native starch", or it undergoes one or more modifications to reach specific properties and is called "modified starch". Worldwide, the main sources of starch are maize (82%), wheat (8%), potatoes (5%), and cassava (5%). Nine years ago, the world starch market was estimated to be 70.0 million tons, based on an annual global growth of 2.2%. The value of the output is worth €15 billion per year. It is worthy to note that, as far back as the first century, Celsus, a Greek physician, had described starch as a wholesome food. Starch was added to rye and wheat breads during the 1890s in Germany and to beer in 1918 in England. The 1930s saw the use of starch as components of salad dressings in mayonnaise. Starch is also used as sweeteners. Acid-catalyzed hydrolysis of starch is used in the improvement of wines in Germany in the 1830s. The leading users of starch are believed to be the brewing, baking powder, and confectionery industries. In fact, the versatility of starch applications is unparalleled. The need for starch continues to increase especially as this biopolymer finds application in other industries including medicine and pharmacy. From serving as a source of food for man, starch has been found to be effective in drying up skin lesions (dermatitis), especially where there are watery exudates. Consequently, starch is a major component of dusting powders, pastes, and ointments meant to provide protective and healing effect on skins. Starch mucilage has also performed well as an emollient and major base in enemas. Because of its ability to form complexes with iodine, starch has been used in treating iodine poisoning. Acute diarrhea has also been effectively prevented or treated with starch-based solutions due to the excellent ability of starch to take up water. In pharmacy, starch appears indispensable. It is used as excipients in several medicines. Its traditional role as a disintegrant or diluent is giving way to the more modern role as drug carrier; the therapeutic effect of the starch-adsorbed, starch-encapsulated, or starch-conjugated drug largely depends on the type of starch. Starch and starch derivatives also play very important roles in environmental management, agriculture, biomedical engineering and textiles, and this appears to be driving the starch industry in the utilisation of raw materials other than maize and potato.

Chemically, starch is a carbohydrate polymer consisting of two inherently incompatible molecules: amylose and amylopectin. Although starch is generally considered inert, the controversy over its inertness rages due to its chemical properties and attendant reactivity. Some have argued that starch has moved from its traditional role as food to being an indispensable medicine. To continually consider starch as an ordinary inert excipient, therefore, is to be oblivious of the influence this important biopolymer plays in various fields of human endeavor; roles which are directly or indirectly related to its chemical properties. Starch is very

sensitive to acid attack, and this is equally attributed to its chemical properties. The chemical properties of starch as conferred by the presence, amount and/or quality of amylose and amylopectin molecules, granule structure, and the nature and amounts of the lipid and protein molecules vary with the botanical source of the starch. Therefore, what has been discovered about the structural features of one type of starch does not necessarily apply to other types of starch.

*Chemical Properties of Starch* is a collective project that brings together authors of varying backgrounds, experience, and expertise in starch.

In order to simplify and enable the reader to appreciate the interesting perspectives brought to bear by this team, this book has been organised into four major parts;


This book comprises 10 chapters, arranged in an ordered sequence, starting with the basics of starch; micrometry, i.e. the qualitative and quantitative morphological, chemical, and genetic properties of starch. It continues with starch as food and how the chemical properties influence the delicacies peculiar to the Indian community. Following this are the chapters on resistant starches, which comprehensively examine the benefits of resistant starch to human health by promoting a balanced blood sugar and beneficial gut bacteria. There are also special articles on the modification and applications of starch and starch derivatives as well as the role of starch chemistry on its properties, written by authors based on their practical experience in the industry and academia, making this book a very rich compendium. In general, this book provides the reader with an excellent and rich knowledge of the role the botanical or biological source of starch play in determining its chemical properties and the influence of the chemical properties on starch functionalities and roles in various fields. The book will be useful to pharmacists, agriculturists, chemists, biologists, chemical engineers, and health research scientists. University professors, research professors, researchers, and their undergraduate and postgraduate students will find this multi-authored, multi-dimensional book useful when preparing their thesis on starch-related projects.

Finally, I wish to express my gratitude to the authors for agreeing to share their wealth of experience in their contributions, my excellent Author Service Manager, Marijana, and to my wife, Comfort, who endured my late nights in the course of editing the contributions for this book.

> **Martins Emeje** National Institute for Pharmaceutical Research and Development, Abuja, Nigeria

Section 1
