Polyphenols: Properties, Recovery, and Applications

Charis M. Galanakis

• Publisher: Woodhead Publishing
• Year: 2018
• Print ISBN: 9780128135723
• eBook ISBN: 9780128135730
• Topic: Technology & Engineering
• Subtopic: Food Science
• Index: Technology & Engineering

Polyphenols: Properties, Recovery, and Applications covers polyphenol properties, health effects and new trends in recovery procedures and applications. Beginning with coverage of the metabolism and health effects of polyphenols, the book then addresses recovery, analysis, processing issues and industrial applications. The book not only connects the properties and health effects of polyphenols with recovery, processing and encapsulation issues, but also explores industrial applications that are affected by these aspects, including both current applications and those under development.- Covers the properties and health effects of polyphenols, along with trends in recovery procedures and applications- Addresses recovery, analysis and processing issues- Concludes with coverage of the industrial applications of polyphenols

Part B

Recovery and Processing of Polyphenols From Target Sources

Outline

5. Target sources of polyphenols in different food products and their processing by-products

6. Polyphenols analysis and related challenges

7. Recovery technologies and encapsulation techniques

8. Emerging technologies for the extraction of polyphenols from natural sources

9. Technological aspects and stability of polyphenols

5

Target sources of polyphenols in different food products and their processing by-products

Urszula Tylewicz¹, Małgorzata Nowacka², Beatriz Martín-García³, Artur Wiktor², and Ana Maria Gómez Caravaca^{3 1}Alma Mater Studiorum-Università di Bologna, Cesena (FC), Italy ²Warsaw University of Life Sciences (WULS-SGGW), Warsaw, Poland ³University of Granada, Granada, Spain

Abstract

This chapter provides a description of the different natural sources of polyphenols, such as fruit and vegetables, cereals and legumes, coffee, tea, olive oil, cocoa, herbs, and spices. Industrial processing of these raw materials leads to the production of a huge amount of by-products, which are a good source of antioxidants, mainly polyphenols. Recently, the recovery of these high added-value compounds from food processing by-products is an important issue. Therefore particular attention in this chapter is focused on the new trend of food processing by-products and plant waste extracts as a source of polyphenols.

Keywords

Food processing by-products; Fruit; Leaves; Plant waste extracts; Polyphenols; Pomace; Seeds

1. Introduction

Polyphenols are the most abundant antioxidants in the human diet, and the largest and best studied class of polyphenols are phenolic acids, flavonoids, and tannins. They can exert a protective action on human health thanks to their antioxidant, immunomodulatory actions and anticancer and antibacterial activity. However, in some cases, polyphenols are considered to decrease the nutritional value since tannins for instance can reduce the digestibility of food.

Raw fruit and vegetables are a good source of polyphenols. However, due to their seasonal nature they are often industrially processed. Consequently, a significant amount of by-products (peel, pulp, seeds, stones, stem) are produced, which contain valuable bioactive compounds, such as flavonols, flavanols, anthocyanins, and phenolic acids (ferulic acid, vanillic acid, caffeic acid, etc.). Cereals (maize, wheat, rice, and also barley, sorghum, oat, and rye) and their by-products (e.g., bran) are rich in a variety of phytochemical compounds, such as phenolic compounds, carotenoids, vitamin E, γ-oryzanols, dietary fibers, and β-glucans. The phenolic compounds in legumes (chickpeas, beans, lentils, and peas) and their by-products (e.g., seed coat) are mainly represented by tannins, phenolic acids, and flavonoids. Another good source of polyphenols is present in beverages such as coffee, tea, wine, and beer and also in their by-products created during their production (e.g., coffee silverskin, spent coffee grains, grape pomace, brewers’ spent grain). Olive oil and by-products (olive leaves, olive mill waste water (OMWW), and pomace) generated during the olive oil industrial processing are rich in secoiridoids, phenyl alcohols, flavonoids, lignans, and phenolic acids. Cocoa and cocoa-derived products contain mainly flavanols such as epicatechin (EC), catechin, and procyanidins. Finally, herbs and spices (e.g., coriander, thyme, sage, rosmarin, etc.) and waste extracts obtained from the essential oil production are also a good source of polyphenols, mainly phenolic acids. This chapter provides a description of the main natural sources of polyphenols, with particular attention focused on the new trend of food processing by-products and plant waste extracts.

1.1. Fruits

Fruits are a rich source of polyphenols, which are natural antioxidant compounds with multiple biological effects. They are present in the fruits, seeds, and leaves and their amount depends on the cultivar, condition of cultivation, maturity of the fruit, type and variety and part of the plant (Kondo et al., 2002; Kalinowska et al., 2014; Díaz-de-Cerio et al., 2017). Polyphenols are the most abundant antioxidants in the human diet and the lack of these compounds leads to health problems. Biochemical studies indicate that free radicals and their reactive products are responsible for the formation of civilization diseases, such as atherosclerosis, Alzheimer disease, Parkinson disease, cancer, faster aging, heart attacks, cardiovascular disease, etc. (Madsen et al., 2000; Heinonen and Meyer, 2002; Sluis et al., 2002; Schirrmacher and Schempp, 2003; Wolfe et al., 2003; Lima et al., 2014; Gowe, 2015; Skrovankova et al., 2015; Helkar et al., 2016; Bondonno et al., 2017).

A very important role in preventing the effects of free radicals is played by the polyphenols provided by food. The best sources of polyphenols are raw fruits and vegetables. However, due to their seasonal nature they are often processed in the industries. Consequently, a significant amount of by-products (peel, pulp, seeds, stones, stem) are produced. It is estimated that from 30% to even 75% of processed fruits and vegetable are wasted. Food production generates a large amount of waste that is used in small quantities as animal feed and the rest cause a growing environmental problem (Dhillon et al., 2013; Kammerer et al., 2014; Lima et al., 2014; Gowe, 2015; Helkar et al., 2016). However, by-products contain valuable components such as bioactive compounds, phytochemicals, flavor compounds, carbohydrates, polysaccharides, proteins, vitamins, minerals, etc., which can be considered as cheap sources of natural food additives and nutraceutical ingredients to produce innovative food products, enriched food, or supplements (Gowe, 2015; Varzakas et al., 2016; Kowalska et al., 2017).

1.1.1. Apple and apple pomace

The world production of apples is the third largest production, just after the bananas and watermelons. In 2014, the apple harvest was more than 84 million tons (FAOSTAT, 2017). Apple is a fruit containing about 85% of water, 14% of carbohydrates, including fiber and sugars, vitamins, minerals, and polyphenols (Bondonno et al., 2017). Apple contains phenolic compounds in a quantity of 296.3 mg GAE/100g FW, which are present mainly in soluble-free form, while only small amounts are represented by bound phenolics (Sun et al., 2002).

The major apple polyphenols are flavonoids such as procyanidins, catechins, ECs, quercetin glycosides, dihydrochalcones (phlorizin), hydroxybenzoic acids (p-hydroxybenzoic acid, protocatechuic acid, gallic acid, syringic acid, gentisic acid), and hydroxycinnamic acids and their derivatives (p-coumaric acid, caffeic acid, ferulic acid, chlorogenic acid [CGA]) (Kalinowska et al., 2014; Bondonno et al., 2017).

The content of bioactive compounds is higher in epider...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of contributors
• Preface
• Part A. Metabolism and Health Effects of Polyphenols
• Part B. Recovery and Processing of Polyphenols From Target Sources
• Part C. Application of Polyphenols in the Industry
• Index