Technologies for Value Addition in Food Products and Processes

Sankar Chandra Deka, Dibyakanta Seth, Nishant Rachayya Swami Hulle, Sankar Chandra Deka, Dibyakanta Seth, Nishant Rachayya Swami Hulle

• Publisher: Apple Academic Press
• Year: 2019
• Print ISBN: 9781771887984
• eBook ISBN: 9780429515996
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Science General
• Index: Technology & Engineering

The new volume looks at some important emerging food processing technologies in light of the demand for functional food products and high-value and nutritionally rich products. Technologies for Value Addition in Food Products and Processes covers a selection of important recent developments in food processing that work to enrich or maintain nutritional value of food products, including such applications as non-thermal plasma, refractance window drying, extrusion, enzyme immobilization, and dry fractionation.

Dry fractionation, in particular, has emerged as a sustainable alternative to wet processes in last three decades for producing protein concentrates from legumes. Several chapters on fish processing cover both traditional knowledge and advances in fish processing technologies. A chapter on bioethanol production discusses the past and present status of the industry, focusing on economic feasibility and environmental viability. A chapter also discusses traditional fermentation process and nutritional aspects of ethnic foods followed by the Rabha-Hasong, Mishing and Karbi communities of Assam, India.

With the contribution from experts in their respective fields, this volume provides new information on novel food processing technologies.

Chapter 1

Rheology: A Tool to Predict Quality of Foods

Mamta Bhardwaj, Renuka Singh, and D. C. Saxena

Department of Food Engineering and Technology, Sant Longowal Institute of Engineering and Technology, Longowal-148106, Punjab, India, E-mail: [email protected] (Mamta Bhardwaj), [email protected] (Renuka Singh), [email protected] (D. C. Saxena)

ABSTRACT

The word “food” in itself is a complex system comprising of a wide range of biological components with various rheological characteristics. The diversity in these biological components in different food systems impart various compositional and structural variability to the food, thus, exhibiting different types of rheological behaviors viz. low viscosity fluids (e.g., milk), high viscosity fluids (e.g., ketchup) and hard solids (e.g., candies, and gel). The rheological behavior of food decides the stability and appearance of foods such as in the form of emulsions, pastes, and spreads, etc. Moreover, food quality, apart from its nutritional value, is a function of its rheological properties viz. structure and texture. The rheological characterization of food and food forming components is vital for predicting the food quality. Depending upon the form of a specific product (e.g., suspension, emulsion, gel, paste, liquid, solid, etc.) to be analyzed, a range of rheological techniques, tests, and equipments are available. Processing the rheological data in the form of models is vital to infer its physical significance in relation to the flow behavior. Therefore, the present chapter gives an insight into the application of rheological techniques, tests, and theoretical models to predict the quality of foods.

1.1 Introduction

Rheology is the study of flow and deformation of matter in response to the applied force wherein the relationship between applied stress or strain, deformation, and time is described. Viscosity and elasticity are two principle rheological parameters indispensable for describing the consistency of any material/product. Viscosity is “the resistance to flow,” whereas elasticity is “the ability of a material to resist distortion and come back to its original shape.” Apart from viscous and elastic materials, there is a third category viz. viscoelastic material exhibiting both viscous and elastic character. Food is a complex system, both compositionally and structurally. The difference in the proportion of major food constituents such as carbohydrates, proteins, fibers, fats, and others impart diverse rheological flow and deformation patterns. Therefore, food systems can range from low viscosity fluids (e.g., fruit juice) to hard solids (e.g., candy); the intermediate ones such as bread dough. Rheological tools may be detrimental for deciding the quality of the final food product as its quality is influenced by the majority of factors such as composition, processing parameters, engineering processes, etc. Moreover, the sensory attributes of any food product as perceived by the consumer are influenced by rheological properties such as creaminess, tenderness, hardness, juiciness, smoothness, etc. Thus, rheological characterization is exclusively important starting from the raw materials to the finished food product, i.e., prior to processing (raw materials), during processing (intermediates) and after processing (finished food product) (Tabilo-Munizaga, 2005). Apart from food quality, the rheological data are necessary for plant designs, heat, and mass transfer calculations, designing of mixers, extruders, pumps, etc. (Joshi and Ranade, 2003). Another area where rheology is of utmost concern is the new product development, in the last decade. An emphasis had been laid on the development of functional foods, edible films and coatings, low fat and diet foods, weaning foods and nutraceuticals foods, etc. To achieve this we are playing with the ingredient composition, addition or subtraction of some components, altering the concentrations such as use of fat replacer inulin to develop low fat ice cream (Akalin et al., 2008), addition of mango peel powder to develop high fiber biscuits (Ajila et al., 2008) and many more. These additions or subtractions have a direct influence on the textural properties, mouthfeel, and other characteristics detrimental for the acceptance of the product by the consumers. Hence, the rheological evaluation of food products can be applied for the selection of raw materials and process type, and most importantly, the quality control of the final product.

Putting in a nutshell, the study of rheology and its techniques are necessary for:

• Establishing a relationship between rheological properties and sensory perception;
• Selection of food ingredients for end uses;
• Effect on food quality due to compositional changes;
• Elucidating the textural quality;
• New product development;
• Effect on quality of final food product due to processing.

For rheological characterization, various tools and techniques are available. Also, a range of theoretical and empirical models are available in order to predict the material’s performance during the course of processing and experimental conditions. Foods can be liquids, semi-solid, solid solids, and hard solids (Van Vliet et al., 2009; Foegeding et al., 2011). So as to effectively study the role of rheological tools in food quality prediction, it is imperative to have knowledge of basics of rheology, their classification, different models, and rheological tests. The following chapter, apart from these topics, covers the application of rheological tests in the prediction of food quality and its processes.

1.2 Basics of Rheology

Basic stress (τ) and strain (γ) relationships are keys to all rheological determinations and classifications. Stress is the force per unit area of a material, given by,

$\tau ={\displaystyle \frac{F}{A}}$

where ‘τ’ is the stress and ‘F’ is the force, and ‘A’ is an area on which force is applied. The unit of stress is N/m² or Pa.

The strain is the deformation induced in the material in response to the applied stress, i.e., the relative change in dimensions of the material due to the externally applied force; and it is dimensionless. Rheological materials on the basis of stress-strain behavior can be classi...

Table of contents

• Cover
• Halftitle Page
• Title Page
• Copyright Page
• About the Editors
• Contents
• Contributors
• Abbreviations
• Preface
• 1. Rheology: A Tool to Predict Quality of Foods
• 2. Food Extrusion Technology and Products
• 3. Non-Thermal Plasma (NTP) Applications for Food Decontamination Technology
• 4. Refractance Window Drying and Its Applications in Food Processing
• 5. Enzyme Immobilization in Food and Agriculture: Principles, Practices, and Future Prospects
• 6. Aonla: Composition, Medicinal Properties, Processing, and Food Applications
• 7. Traditional Technology of Fish Preservation in Northeast India
• 8. Advances in Fish Processing Technology
• 9. Nutritional Values and Processing of Tropical Tuber Crops
• 10. Bioethanol Fermentation: The Path Forward for Eco-Friendly and Sustainable Development
• 11. Traditional Fermentation by the Rabha-Hasong, Mishing, and Karbi Communities of Assam and Prospects of Value Addition for Enhancement of Nutritional Qualities in Ethnic Foods
• 12. Rice Protein: Properties, Extraction, and Applications in Food Formulation
• 13. Application of Natural Biopolymer Films as Edible Coatings on Cut Fruits and Vegetables
• 14. Dry Fractionation of Legumes
• Index