Preface

Pectin is one of the main constituents of the cell wall of vegetables and it is an important part of the characteristic components of citrus fruits. These macromolecules are highly hydrophilic polysaccharides that can absorb several times their weight in water. Pectins are obtained mainly from citrus fruits. The pectin industry is one of the most important worldwide, where the products generated are for human consumption. Pectin is best known as a gelling agent, as a texturizer, emulsifier, thickener, and stabilizer. This biopolymeric extract, unlike others, develops a gel in the presence of water, sugar, and acid. The main application of pectins in the food industry is in the manufacture of sweets, jellies, and jams. It is also used as a gelling agent in puddings, as a stabilizer of emulsions and suspensions, a thickening agent in drinks, a stabilizing agent in ice cream and cold desserts, and in solutions for coating sausages and canned meats. In the pharmaceutical field, pectins are used for their protective and regulatory action in the gastrointestinal system. Their detoxifying, anti-cholesterol, immunological, anti-hemorrhagic, anti-cancer and healing effects prolong the therapeutic action by increasing the release times of the active ingredients. It is also used in the formation of films for coating paper and giving softness characteristics in wrapping paper, and as a vehicle in the preparation of barium sulfate suspensions for application in X-ray radiographs. As substitutes for petroleum derivatives, mixtures of pectin and polyvinyl alcohol are used in the manufacture of biodegradable films. These films are biodegradable, recyclable, and allowed for prolonged release of pharmaceutical forms and as protectors or adhesives in pharmaceutical preparations. The pectin industry is a very important engine in the global economy of biopolymers, mainly because of its availability and abundance given in citrus farming.

This book aims to study the use of pectins obtained from citrus and other sources, to obtain food and pharmaceutical additives.

This book consists of the following sections and chapters:

### **Section 1: Pectin Extractions**

**II**

**Chapter 7 147**

Flavonoids and Pectins

*by Zhiping Zhang, Yanzhi He and Xinyue Zhang*

*Chapter 1:* **Extraction and Characterization of Pectins from Peels of Criolla Oranges (***Citrus sinensis***). Experimental Reviews.** Authored by P. Ruano, L. Lazo Delgado, S. Picco, L. Villegas, F. Tonelli, M. E. Aguilera Merlo, J. Rigau, D. Diaz, M. Masuelli.

In this chapter the authors study pectin extraction of criolla orange peel (*Citrus sinensis*) by basic or acid hydrolysis and purification and clarification. Once it is purified, it is characterized in aqueous solution to determine its physicochemical properties such as molecular weight, hydrodynamic radius, hydration value, shape factor, etc. Finally, the product is characterized as a film forming with mechanical and thermal tests.

*Chapter 2:* **Extraction and Purification of Pectin from Agro-Industrial Wastes.**  Authored by E. Venkatanagaraju, N. Bharathi, R. H. Sindhuja, R. R. Chowdhury, Y. Sreelekha.

This chapter focuses on extraction and purification of pectin from various agroindustrial wastes, considered to be main environmental pollutants. The authors explore other sources of pectin or modify the existing sources to obtain pectin with the desired quality attributes. The large variety of applications as well as the increasing number of studies on pectin suggests that the potential of pectin as a novel and versatile biomaterial will be even more significant in the future.
