Modifying Food Texture

Novel Ingredients and Processing Techniques

Jianshe Chen, Andrew Rosenthal

• Publisher: Woodhead Publishing
• Year: 2015
• Print ISBN: 9781782423331
• eBook ISBN: 9781782423515
• Topic: Technology & Engineering
• Subtopic: Food Science
• Index: Technology & Engineering

Modifying Food Texture, Volume 1: Novel Ingredients and Processing Techniques discusses texture as an important aspect of consumer food acceptance and preference, and the fact that specific consumer groups, including infants, the elderly, and dysphagia patients require texture-modified foods.Topics covered include ingredients and processing techniques used in texture modification of foods, an overview of food texture issues, the novel use of processing techniques for texture modification, and the uses of food ingredients in texture-modified foods.- Discusses texture as an important aspect of consumer food acceptance and preference- Presents findings and tactics that address the special needs of infants, the elderly, and dysphagia patients- Topics covered include ingredients and processing techniques used in texture modification of foods, along with an overview of food texture issues, amongst others

Part One

Food texture: an overview

1

Food texture and structure

J. Chen¹; A. Rosenthal^{2 1} Zhejiang Gongshang University, Hangzhou, China
² Coventry University, Coventry, UK

Abstract

As an introduction to the book, this chapter has two main aims: to introduce the concept of food texture and to highlight the determining roles of food structure. The chapter begins with a detailed discussion about the definitions and classifications of food texture and textural features. The discussion was further expanded to examine core textural features for three major food categories: solid, semisolid and fluid. Major mechanical characteristics associated with these textural properties were also discussed. Texture evolution and structure creation during food preparation have been discussed based on food ingredient interactions. With the help of structure mapping, solid and semisolid foods can be further grouped into three dimensions (degree of water content, degree of fat content and degree of structure openness). To set links among food physics, oral physiology and sensory psychology, physiological and psychophysical principles of texture sensation and perception are outlined in the last section of the chapter.

Keywords

Food texture

Food structure

Food sensory

Psychophysics

Food processing

1.1 Introduction

Texture used to be a term for the sensory description of the structure, feel and appearance of fabric materials. It was not until the middle of last century, when food production turned into industrial scale and a food science and technology degree was introduced for the first time, that texture became a sensory term for food description. The earliest literature record of food texture was made in 1949 by Carlson and Hoelzel (1949) in the journal Science. In the 1960s, food texture was commonly accepted as a key quality factor and was recognised as an important research area of the food science and technology discipline. The textbook Food Texture, published in 1962 by Matz (1962) was probably the most representative work of the early stage food texture studies. Since then, research activities in food texture have grown so fast that Journal of Texture Studies was launched in 1969 to disseminate research findings in this area. A quick search on Scoups shows a fast-growing number of published articles on food texture and related topics. In the entire decade of the 1960s, there were only 18 publications. This number increased to 107 in the 1970s, 217 in the 1980s, 741 in the 1990s and 3711 in the 2000s. In the past 5 years, over 700 food texture-related research articles were published each year.

The continuously growing activities in food texture research have been first driven by the need for fundamental understanding of human sensory perception towards food, in which food physics (in particular food rheology) and sensory psychology have been the most active areas. Another major factor in the study of food texture came from the food industry, driven by the need for functional ingredients and innovative technologies for improved textural quality of food and the need for reliable instrumental characterisation of textural properties for quality assurance and consumer preference prediction. In recent years the food industry is under a growing pressure to produce healthy food for the needs of some specific consumer groups: the fast-growing population of obese and overweight and the fast-growing population of elderly people. For the former, healthy food with significantly reduced energy density is required. However, for elderly and other vulnerable consumers, safety and convenience of food consumption is the top priority. Texture modification plays a key role in the design and manufacturing of quality food for both consumer groups.

Food texture study in the last half century has led to some major achievements that can be summarised in three areas. The first major achievement is on the fundamental understanding of the physical (mechanical) nature of food texture (van Vliet, 2002). Structure and structural deformation have been recognised as the core of texture sensation, and how a food material resists deformation is the key determining factor. Based on this recognition, food rheology was once seen as a base of texture study, but limitations of the approach were later pointed out by Bourne (1974). Fundamental physical principles associated with food fracture and deformation have now been superbly explained by van Vliet in his recent book (van Vliet, 2013). The second major achievement is the quantitative and semiquantitative methods for the characterisation of texture properties for a wide range of food materials, from thin liquid beverage to very cohesive paste, from a wobbly gel to a hard solid candy. The latest progresses in this area have been nicely summarised by Kilcast in his latest textbook, in which various instrumental approaches are discussed for texture characterisation for a wide range of food categories (Kilcast, 2013). The third major development has been on texture modification, a hot topic that emerged in the past decade driven by consumers’ needs. The use of alternative ingredients and the application of novel processing techniques are probably the two main approaches adopted by the food industry for both texture creation and texture modification.

With this background in mind, this book aims to address the concerns of the food industry in terms of the use of novel food ingredients and new processing techniques for food texture modification. The emphasis of the book is on the needs of specific consumer groups, in particular those disadvantaged users such as elderly, hospital patients and infants. As an introduction, this chapter will discuss concepts of food texture, what it means and how it is defined. Food structure and its important implications to texture sensation and texture characterisation will also be discussed in this chapter.

1.1.1 Food texture, definition and classification

The real sensory meaning of food texture varies hugely among consumers as well as among food researchers. There has been a great effort from food researchers to agree on the definitions of texture terms. Based on the general consensus that texture is about the constitution, structure or substance of anything with regard to its constituents and formative elements, a number of definitions have been produced. A few of the most commonly referenced ones are given here:

• “All the mechanical, geometrical and surface attributes of a product perceptible by means of mechanical, tactile and, where appropriate, visual and auditory”. International Organisation for Standardization (1992)

• “Primarily the response of the tactile senses to physical stimuli that result from contact between some part of the body and the food. The tactile sense (touch) is the primary method for sensing texture but kinesthetics (sense of movement and position) and sometimes sight (degree of slump, rate of flow), and sound (associated with crisp, crunchy and crackly textures) are also used to evaluate texture”. Bourne (2002)

• “Texture is the sensory and functional manifestation of the structural, mechanical and surface properties of foods detected through the senses of vision, hearing, touch and kinaesthetic”. Szczesniak (2002)

All these descriptions indicate that food texture is a sensory experience of multiple sensory stimuli working in combination and synchronisation. The texture of a food originates from its structure or microstructure (from the molecular level to the microstructure and macroscopic level). The sensation of food texture depends highly on how the structure deforms and breaks when handled and eaten. Therefore, any factor (e.g., ingredient interactions, processing conditions, storage and packaging, etc.) that influences the structural properties of the food will affect its texture.

According to the preceding definitions, textural properties of food can be categorised into three groups depending on the sensation mechanisms: the visual, the acoustic and the tactile. For visual texture, properties such as smoothness, glossiness, thin and viscous are the most common examples. The appearance and light reflection of the food determine visual texture (Chen, 2007). Texture properties associated with hearing are typically represented by the crispness and crunchiness, the two most beloved texture features linked to the noise produced during the fracture of a solid food. Such texture features are closely associated with other sensory stimuli detected by mechanoreceptors. Internal scull vibration has also been shown to be important to the sensation of these texture features (van der Bilt et al., 2010). Of all texture features, tactile texture is probably the most common and often the core focus of texture study. Tactile texture features are sensed by the direct contact between the food and human skin (hand or oral surfaces).

It has recently been proposed that sensation of food texture could be made through two very different physical principles: oral rheology and oral tribology (Chen and Stokes, 2012). Based on this theory, texture properties could also be categorised as texture associated with bulk deformation (rheology-originated; e.g., firmness, springiness, cohesiveness), texture associated with relative surface movement (tribology-originated; e.g., smoothness, roughness) and those sensed through combined rheology and tribology mechanisms (e.g., slipperiness, creaminess) (Chen and Stokes, 2012).

A big difficulty of texture analysis is the very wide range of texture terminologies and the very different use of textural vocabularies among different cultures and consumer groups. Hayakawa et al. (2013) conducted a comprehensive study of texture terms among Japanese consumers and noted as many as nine major categories, each consisting of a long list of textural terms and descriptions. More detailed analysis of texture terminologies and classification can be seen in Chapter 1, volume 2 of this work.

It is also a common knowledge that texture sensation occurs simultaneously with the appreciation of the taste and aroma. However, which of these three contributes most to one’s sensory experience and liking of a food product has caused disput...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• Woodhead Publishing Series in Food Science, Technology and Nutrition
• Preface
• Part One: Food texture: an overview
• Part Two: Novel use of food ingredients for food texture modification
• Part Three: Novel processing techniques for food texture modification
• Part Four: Modifying the texture of specific food commodities
• Index