Sensory Analysis for Food and Beverage Quality Control

A Practical Guide

David Kilcast

• Publisher: Woodhead Publishing
• Year: 2010
• ISBN:
  9781845699512
• Topic: Technology & Engineering
• Subtopic: Food Science
• Index: Technology & Engineering

Producing products of reliable quality is vitally important to the food and beverage industry. In particular, companies often fail to ensure that the sensory quality of their products remains consistent, leading to the sale of goods which fail to meet the desired specifications or are rejected by the consumer. This book is a practical guide for all those tasked with using sensory analysis for quality control (QC) of food and beverages.

Chapters in part one cover the key aspects to consider when designing a sensory QC program. The second part of the book focuses on methods for sensory QC and statistical data analysis. Establishing product sensory specifications and combining instrumental and sensory methods are also covered. The final part of the book reviews the use of sensory QC programs in the food and beverage industry. Chapters on sensory QC for taint prevention and the application of sensory techniques for shelf-life assessment are followed by contributions reviewing sensory QC programs for different products, including ready meals, wine and fish. A chapter on sensory QC of products such as textiles, cosmetics and cars completes the volume.

Sensory analysis for food and beverage quality control is an essential reference for anyone setting up or operating a sensory QC program, or researching sensory QC.

• Highlights key aspects to consider when designing a quality control program including sensory targets and proficiency testing
• Examines methods for sensory quality control and statistical data analysis
• Reviews the use of sensory quality control programs in the food and beverage industry featuring ready meals, wine and fish

Part I

Designing a sensory quality control program

1

Designing a sensory quality control program

M.A. Everitt, ME Consultancy Ltd, UK

Abstract:

This chapter provides an overview of some of the main areas that need due consideration when planning to establish a sensory quality control program. Particular attention is given to the importance of management commitment, sensory specifications and common failings, approaches used to set sensory targets, and training regime.

Key words

sensory specifications

consumer focus

sensory training program

quality grading

1.1 Introduction

Gaining and maintaining a quality advantage have become primary competitive issues within the food and drink industry. As the range within sectors plus the overall standard of food available to consumers continues to increase so has the need for businesses to review their policies towards quality versus production volume. Defining product quality and setting the parameters by which it is measured and controlled has been and remains a major challenge with regard to the sensory element of the product specification.

The approach taken by a company in the way it defines and subsequently measures quality can have a major influence on the degree to which a sensory program is incorporated into the overall quality monitoring system. Gavin (1984) discusses five classical approaches that can be used to define product quality:

1. Transcendent approach based on philosophy which states that quality is recognised only through experience and cannot be precisely defined.

2. Product-based approach founded on economics which views quality as a precise and measurable property relating to variation in the amount of a specified characteristic or ingredient.

3. Manufacturing-based operations management approach which judges quality primarily by the level of conformance with a defined specification; any deviation is seen as a reduction in quality.

4. Value-based operations management approach which uses cost and price to define quality; a quality product would provide performance at an acceptable price or conformance at an acceptable cost.

5. User-based approach combines economics, marketing and operations management principles with the focus being on consumer satisfaction; a quality product would achieve greatest satisfaction for a specified group of consumers.

A sensory quality control (QC) program will be most readily accepted and effectively incorporated into businesses that take the last approach. This approach also helps companies maintain a realistic balance between product quality, production volume and cost.

A consumer-focused route is therefore advocated as most effective for setting up the sensory component of a QC program although other approaches based more on the use of internal business expertise are discussed.

1.1.1 Principle and objective of a sensory QC program

The main aims of QC are to ensure:

• legal requirements are met;

• the product is safe and fit for use;

• there is compliance with nutritional guidelines and tolerances;

• the agreed/declared weight is provided;

• deviation from expected quality is kept within an acceptable tolerance.

The last area tends to be the most difficult to define and measure within a food or beverage program as the criteria typically used to judge ‘expected quality’ will primarily relate to a product’s sensory aspects (i.e. appearance, flavour and, texture) which are more prone to subjective interpretation due to personal perceptions and preferences.

This can lead to the sensory part of a product quality specification being inadequately or in some instances inappropriately defined owing to insufficient appreciation of the sensory features that have most affect on the target consumers’ perception of quality.

1.1.2 Common failings in defining the sensory specification

Visual characteristics

Because visual characteristics are the most ‘tangible’ of all the sensory attributes these tend to receive the most attention with physical features (e.g. depth of a sponge layer, number of nuts on top of a Dundee cake) often taking precedence over the true sensory attributes such as depth and uniformity of colour, degree of clarity and brightness.

Flavour, texture and mouth-feel characteristics

Descriptions relating to these modalities are often written in vague, generalised terms (e.g. ‘typical flavour’, ‘freshness of flavour’, ‘standard texture’) which can lead to varied assumptions being made across assessors about the interpretation. Even when individual attributes are listed, issues can still arise, especially if the author of the specification is not familiar with sensory evaluation principles and the need for precise, unambiguous terminology.

Terms can remain bundled and confusing (e.g. confectionery flavour, ripe flavour) or be too technical for general application (e.g. diacetyl instead of ‘buttery’, dimethyl sulphide instead of ‘cabbagey’, 2,4,6-trichloroanisole instead of ‘musty’).

Relevance and priority of sensory attributes

To aid initial focus when defining the specification, the sensory quality attributes can be considered as falling into two main groupings: those which relate to the key characteristics that affect consumers’ acceptance of a product and those which are of internal importance to a business in order for it to maintain cost-effective control of the production process and avoid unnecessary wastage of materials.

The relevance of the attributes under the ‘internal’ listing does not ordinarily pose an issue as the association within a business of a defined term with a specific processing factor or raw material is usually readily understood and its need accepted. Visual defects and also off-flavour characteristics are typically most relevant in the ‘internal’ attribute list. Particular visual defects can, for example, indicate the need to reset peeling, cutting or slicing equipment which if left unchecked would lead to increased waste of raw material. The monitoring of specific off-flavours can aid suitable control of factors such as processing temperatures and flow rates, water conservation, fats and oil quality, etc.

Failings are more common regarding specification of the characteristics that relate to consumer acceptance. Attributes that are of no particular importance are often specified whilst those that are key to consumers’ degree of liking can be given low priority or completely overlooked. To ensure that the most appropriate attributes are specified and avoid the risk of subjective influences, the key features that relate to a target market’s expectations of the sensory quality need to be understood by those responsible for setting and applying the specification. The most reliable way to achieve this is for the information gained from consumer and sensory research conducted during a products development or re-development to be communicated to the Quality and Production teams before routine production commences. Unfortunately a common failing is that this information is not transferred, even after the running of detailed and lengthy product development programs. This increases the risk of the sensory quality of routinely produced product deviating from its quality and hence eroding any quality advantage originally established at launch.

Attribute weighting

In addition to defining an appropriate set of sensory characteristics priorities can also be given to specific attributes to aid the most effective and efficient use of the specification. Again if a consumer-focused approach has been used to determine the main sensory criteria this will also enable weightings of importance to be designated more objectively for each and identify which are the most critical to control.

1.2 Company culture and commitment to quality

Without question companies that have established the most effective and successful sensory QC programs are those that have full management support from senior levels down, and view the control of sensory quality as an essential part of the overall QC system. These companies are commonly consumer-focused with a commitment to understanding customer/consumer needs and achieving their total satisfaction, along with an aim for continuous improvement. The internal culture is usually one that encourages team working and ownership of quality across the workforce; it is not seen just as a function of the QC manager and operatives.

Muñoz (2002) lists some of the main reasons that limit or prevent the development of a sound sensory QC program; the key issue running through relates to lack of support, interest and respect within an organisation, in particular from Plant, Quality and R&D management.

1.2.1 Winning management support

As Lawless and Heymann (1998) state, ‘Without management support, especially from manufacturing, a QC program is bound to fail. In a typical case the program will amount to nothing more than “rubber stamping” of supervisory opinion thus supporting a management policy that maximises productivity at the expense of producing unacceptable products’. Production volume will...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributor contact details
• Woodhead Publishing Series in Food Science, Technology and Nutrition
• Preface
• Part I: Designing a sensory quality control program
• Part II: Methods for sensory quality control and analysis of results
• Part III: Sensory quality control in practice
• Appendix: Going forward – Implementing a sensory quality control program
• Index