Colour Additives for Foods and Beverages

Michael J. Scotter

• Publisher: Woodhead Publishing
• Year: 2015
• Print ISBN: 9781782420118
• eBook ISBN: 9781782420200
• Topic: Technology & Engineering
• Subtopic: Food Science
• Index: Technology & Engineering

Food colour additives have been the focus of much research in the last few years, and there is increasing consumer demand for natural and safer synthetic colours. This book reviews the natural and synthetic colours available, their properties and applications, as well as regulatory, sensory and analytical issues. Part one covers the development and safety of food colour additives. Part two covers properties and methods of analysis, and part three focuses on specific food product applications and future trends.- Reviews the natural and synthetic colour additives available for foods and beverages, looking at their properties and applications as well as regulatory, sensory and analytical issues- Expert analysis of natural origin colours, synthetic origin colours, overview of regulations, safety analysis and consumer health- Comprehensive coverage of properties and development in food colours: chemical purity, colour stability, and consumer sensory perception

Part One

Development and regulatory issues for food colourings

1

Food colour additives of natural origin

K. Solymosi¹; N. Latruffe²; A. Morant-Manceau³; B. Schoefs³ [email protected] ¹ Eötvös Loránd University, Budapest, Hungary
² University of Burgundy, Dijon, France
³ University of Le Mans, Le Mans, France

Abstract

Colour is an often overlooked sensory character that certainly influences flavour perception. Pigments colouring food are generally unstable and are modified during processing. To maintain or restore product colour uniformity, colouring agents, considered worldwide as food additives, are intentionally added to food products. The natural food additives market has been growing extensively since the last century due to the potential hazards of artificial food additives and the potential benefits of biologically active compounds. In this chapter, a fairly compressed overview of the most important colours of natural origin as well as information about less common or/and promising colouring molecules are provided.

Keywords

Artificial

Colour additives

Food

Molecules

Natural

1.1 Introduction

Food colour is an often overlooked sensory character that certainly influences flavour perception (Hutchings, 2003). Fashioning the colour and/or the taste of vegetables seems today attainable using LED illumination as pre- or post-harvest treatment (reviewed in Darkó et al., 2014) but would be totally inoperant with processed food. Actually, pigments colouring food products are generally unstable (reviewed in Schoefs, 2002, 2005) and the harsh conditions applied during food processing often destroy them (reviewed in Schoefs, 2003). Therefore, to maintain or simply restore product colour uniformity, colouring agents are intentionally added to food products. Thus, these agents belong to the food additive category of compounds (European Commission and the Council, 2008). The food additives market has been affected by two major events – namely, the progressive growth of the processed food market after World War II and, more recently, the preference of consumers for natural food additives over synthetic dyes. The former has mostly impacted the amounts of food additives required, whereas the latter relies at the same time on the strong concerns about the potential hazards of artificial food additives in food and on the idea that natural products are biologically active compounds and, therefore, can promote good health conditions (Hutchings, 2003). Natural substances must fulfill the three following criteria: (i) exist in nature, (ii) raw material must be natural, and (iii) extraction processes must be nonchemical (Bomgardner, 2014). Food additives are generally divided into six categories: taste enhancers, preservatives, stabilisers, emulsifiers, antioxidants, and colouring agents (Rangan and Barceloux, 2009; Shim et al., 2011). This chapter is dedicated to this last category. Besides the generally approved and strictly regulated food colourings of natural origin, such as anthocyanins, betalains, caramel colours, carminic acid, carotenoids, chlorophyll and chlorophyll derivatives, curcumins, and riboflavin (Scotter, 2011), some information about promising or less common colouring molecules are also provided. It has to be mentioned that depending on their manufacturing, use, and properties different food extracts with colouring properties may be either classified as colours (food additives, ‘food colourants’, see above) (European Commission and the Council, 2008) or as foods (or food ingredients) with colouring properties (also termed ‘colouring foods’) (Matulka and Tardy, 2014). Saffron, tomato concentrate, cherry juice, and squid ink belong to this latter, recently established, and less strictly regulated category in the EU (European Commission and the Council, 2009; Matulka and Tardy, 2014; Melchor and Di Mario, 2014). However, other countries (United States, China, Russia, etc.) have different regulations for food extracts with colouring properties (reviewed in Matulka and Tardy, 2014), but discussion of this issue is beyond the scope of this chapter.

From a chemistry perspective, food colouring agents share the property to absorb light due to the conjugated double bonds they contain, creating a delocalised electron system. The number of conjugated double bonds is indicative of the wavelength of the absorbed light (Schoefs, 2002). Traditional sources for natural food colour additives are essentially plants, plant extracts, and, to a lesser extent, other sources such as animals (most importantly insects), algae, fungi, and bacteria (including cyanobacteria) are also used. For the purposes of this chapter, inorganic colours derived from minerals are not treated as they are usually considered as non-natural (e.g. Mortensen, 2006; Scotter, 2011).

It has been shown that the influence of colour on food acceptability, choice, and preference comes more from education than any inherent psychophysical characteristics (Clydesdale, 1993). Considering that (i) the brain associates colour with flavour, (ii) the initial food perception occurs within the first 90 s of observation, and (iii) approximately 75% of the assessment is based on colour (Singh, 2006), it is clear that if food colour differs from the consumer's expectation, flavour identification is decreased. This means that the subjective colour-flavour association becomes stronger under such conditions, and the colour has a dominant effect on food acceptance (Roth et al., 1988). This is true for simple and complex food as well (Pangborn et al., 1963). In other words, if colour is unacceptable or unappealing, the other factors important for consumers' liking (i.e. flavour and texture) are unlikely to be judged at all (Francis, 1995). Consequently, a deep and renewed knowledge of food colour additives is requisite. This is even more important because (i) toxic compounds can be formed during food colour additive production (e.g. in case of caramel colours), (ii) colour additives can be subjected to fraudulent practices (Murphy, 2009), (iii) they are added to new products, and/or (iv) they may be at the origin of the development of sensitivity or adverse reactions in the population (Madsen, 1994; Fuglsang et al., 1994). Conversely, the health promoting potential of many of these natural food colourants remains to be (re)discovered, especially when diseases connected with longer life expectancy are concerned, including, among others, cancer, Parkinson's disease, memory failure, dementia, and Alzheimer's disease. To highlight the importance of such diseases, it is enough to recall the huge progression of Alzheimer's disease: the number of patients diagnosed was 35 million in 2010; the projection for 2030 is 65 million and is 115 million in 2050. Although, the exact mechanisms in which food microcomponents are involved in human health may remain obscure, several experimental studies have reported positive effects on health. For instance, experiments revealed a decrease of the aberrant proteins thought to be involved in Alzheimer's disease in the presence of polyphenols a...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• List of contributors
• Woodhead Publishing Series in Food Science, Technology and Nutrition
• Introduction
• Acknowledgement
• Part One: Development and regulatory issues for food colourings
• Part Two: Properties and analysis of food colours
• Index