Emerging Technologies for Food Processing

Da-Wen Sun

• Publisher: Academic Press
• Year: 2005
• ISBN:
  9780080455648
• Topic: Technology & Engineering
• Subtopic: Food Science
• Index: Technology & Engineering

Emerging Technologies for Food Processing presents a comprehensive review of innovations in food processing, stresses topics vital to the food industry today, and pinpoints the trends in future research and development. This volume contains 27 chapters and is divided into six parts covering topics such as the latest advances in non-thermal processing, alternative technologies and strategies for thermal processing, the latest developments in food refrigeration, and current topics in minimal processing of vegetables, fruits, juices and cook-chill ready meals and modified atmosphere packaging for minimally processed foods.* Each chapter is written by international experts presenting thorough research results and critical reviews* Includes a comprehensive list of recently published literature* Covers topics such as high pressure, pulsed electric fields, recent developments in microwave heating, and vacuum cooling

Part 1

High Pressure Processing

Outline

Chapter 1: High Pressure Processing of Foods: An Overview

Chapter 2: High-pressure Processing of Salads and Ready Meals

Chapter 3: Microbiological Aspects of High-pressure Processing

1

High Pressure Processing of Foods: An Overview

Eamonn Hogan¹, Alan L Kelly² and Da-Wen Sun¹, ¹Food Refrigeration and Computerised Food Technology Group, National University of Ireland, Dublin, Ireland; ²Department of Food and Nutritional Sciences, University College Cork, Cork, Ireland

Publisher Summary

The application of any new technology presents significant challenges to food technologists and food researchers. High-pressure (HP) processing offers the food industry a technology that can achieve the food safety of heat pasteurization while meeting consumer demand for fresher-tasting minimally-processed foods. In addition, other favorable organoleptic, nutritional, and rheological properties of foods have been demonstrated following HP, in comparison to heat processing. The retention of color, aroma, and the preservation of nutritive components are enormous benefits for both food processing industry and consumers. Also, from a food processing/engineering perspective, key advantages of high-pressure applications of food systems are the independence of size and geometry of the sample during processing, possibilities for low temperature treatment, and the availability of a waste-free, environment-friendly technology. Application of HP can inactivate microorganisms and enzymes and modify structures while having little or no effects on nutritional and sensory quality aspects of foods. HP food processing today is being used on an ever-increasing commercial basis. Opportunities clearly exist for innovative applications and new food product development. HP can affect the functionality of protein and carbohydrate molecules often in unique ways, which may allow optimization of food manufacturing processes and production of novel foods. The range of commercially available HP-processed products is relatively small at present, but there are opportunities for further development and production of a wide range of HP-treated products.

The quality and safety of food products are the two factors that most influence the choices made by today’s increasingly demanding consumers. Conventional food sterilization and preservation methods often result in a number of undesired changes in foods, such as loss of smell, colour, flavour, texture and nutritional value – in short, a reduction in the apparent freshness and quality of the final product. High-pressure (HP) processing, also sometimes known as high hydrostatic pressure (HHP), or ultra high pressure (UHP) processing, is a relatively new non-thermal food processing method that subjects liquid or solid foods, with or without packaging, to pressures between 50 and 1000 MPa. Extensive investigations have revealed the potential benefits of high pressure processing as an alternative to heat treatments. These benefits are apparent in various areas of food processing, such as the inactivation of microorganisms and enzymes, denaturation and alteration of the functionality of proteins and structural changes to food materials.

1 Introduction

Food processing involves the transformation of raw animal or plant materials into consumer-ready products, with the objective of stabilizing food products by preventing or reducing negative changes in quality. Without these processes, we would neither be able to store food from time of plenty to time of need nor to transport food over long distances (Lund, 2003).

To consumers, the most important attributes of a food product are its sensory characteristics (e.g. texture, flavour, aroma, shape and colour). These determine an individual’s preference for specific products and minor differences between brands of similar products can have a substantial influence on acceptability. A goal of food manufacturers is to develop and employ processing technologies that retain or create desirable sensory qualities or reduce undesirable changes in food due to processing.

Physical (e.g. heating, freezing, dehydration, and packaging) and chemical (e.g. reduction of pH or use of preservatives) preservation methods continue to be used extensively and technological advances to improve the efficiency and effectiveness of these processes are being made at a rapid rate. The basis of these traditional methods involves reducing microbial growth and metabolism to prevent undesirable chemical changes in food. Probably the most common method of food preservation used today is thermal treatment (e.g. pasteurization, sterilization). Although heating food effectively reduces levels of microorganisms such as bacteria, such processing can alter the natural taste and flavour of food and destroy vitamins.

Therefore, alternative or novel food processing technologies are being explored and implemented to provide safe, fresher-tasting, nutritive foods without the use of heat or chemical preservatives. Innovative non-thermal processes for preservation of food have attracted the attention of many food manufacturers. In the search for new processing methods, particularly for certain products, the application of high-pressure (HP) processing has shown considerable potential as an alternative technology to heat treatments, in terms of assuring safety and quality attributes in minimally-processed food products (Palou et al., 2002).

Consumer demand for minimally-processed food products has presented particular challenges to food processors. Most retailers are reporting up to 30 per cent growth in fresh, chilled and healthy food sales. These products all face the same problem: how to keep the food fresh and healthy with high retention of vitamin and nutrient levels, while offering a reasonable shelf-life and convenience and assuring food safety. HP technology potentially answers many, if not all, of these challenges. Unlike heat treatment, HP treatment does not reduce the quality of foods and pressure is evenly and instantaneously transmitted throughout the sample, which allows products without over-treated parts to be obtained. HP processing can thus facilitate the production of foods that have the quality of fresh foods but the convenience and profitability associated with shelf-life extension (McClements et al., 2001).

2 Principles of high pressure processing

Currently, a great deal of research is being directed towards understanding the effects of high pressure (HP) on food and food ingredients. Some key findings in this regard will be summarized in this chapter.

2.1 Background

Studies of the effects of high pressures on foods date back over a century. In 1899, Bert Hite of the Agriculture Research Station in Morganstown, West Virginia, USA, designed and constructed a high-pressure unit to pasteurize milk and other food products (Hite, 1899). Hite constructed a machine that could reach pressures in excess of about 6800 atmospheres (approximately 700 MPa) and he and his co-workers examined the potential use of HP processing for a wide range of foods and beverages, including the pressure inactivation of viruses. The level of sophistication that was accomplished is remarkable, give...

Table of contents

• Cover image
• Title page
• Table of Contents
• About the Editor
• Contributors
• Preface
• Part 1: High Pressure Processing
• Part 2: Pulsed Electric Fields Processing
• Part 3: Other Non-thermal Processing Techniques
• Part 4: Alternative Thermal Processing
• Part 5: Innovations in Food Refrigeration
• Part 6: Minimal Processing
• Index