ODOUR AND FLAVOUR IN THE WORLD OF PACKAGING

Transcription

1 ODOUR AND FLAVOUR IN THE WORLD OF PACKAGING

2 The scent of a flower, the bouquet of a fine wine, or all the flavours and odours which we enjoy while partaking of a well-prepared dinner are important aspects of quality of life. THE LABORATORY FOR SENSORY AND CHEMICAL ANALYSES Sensory analysis using statistical calibration and a gas chromatograph with an odour detector (GC sniff). Chemical analysis using gas chromatography and mass spectrometry. Unique equipment for taking gas samples at room temperature. Measurements of the effects of aromas on packaging materials/permeability. The laboratory is accredited for sensory measurement by the Swedish national accreditation authority, SWEDAC (the Swedish Board for Accreditation and Conformity Assessment). This guarantees that tests are objectively carried out using approved and tested methods. Many of the events we look back on with pleasure are closely related to odours. Not that we always remember them, but when we recognise an odour the memory returns. Although the human sense of smell is much less developed than a dog s, for example, it is of great importance in our daily life. Much more so than we normally admit. We generally deal with odours and tastes in our subconscious; we are affected by them without always being aware of them. We also use our senses of smell and taste in another way than just for rich, sensual experiences. It is equally important to be able to determine if food is suitable for human consumption or not. Most modern people have great faith in today s food production and packaging techniques, but they nevertheless rely on smell and a little taste to decide whether the product can be eaten or not. Iggesund Paperboard is a leading manufacturer of paperboard for packaging. Our task is to manufacture paperboard that neither adds nor removes flavours or odours from the food or medicine in the package. And that is something that requires knowledge. A package is more than just paperboard. It is a construction which is glued together, on which information is printed, and which may have an added barrier in the form of plastic or foil. Even more knowledge is needed to be able to see how the different aspects of packaging affect each other and, in the end, the consumer s perception of the package s contents.

3 FLAVOUR A SIMPLE MATTER? Our senses of smell and taste are intimately connected. What we usually call flavour is actually a combination of signals coming from our taste buds on the tongue and olfactory cells in the nasal epithelium. You realise how important your sense of smell is for flavour if you eat your favourite dish when you have a cold. Suddenly what usually tastes so good has almost no flavour at all. Senses such as vision, hearing and touch react to external stimulation in the form of light and sound waves, temperature and pressure. The senses of smell and taste, however, are chemical senses since they react to chemical substances in the environment. The receptors of taste are the taste buds on the tongue. When a substance is dissolved in saliva, the cells in the taste buds react to the properties of the new substance and send a message to the brain. The taste buds determine the flavour, based on six taste sensations: SWEET BITTER SALTY UMAMI SOUR METALLIC For a long time scientists believed that the first four were the only basic taste sensations, but gradually they also discovered that umami and metallic are also basic tastes. Umami is usually associated with monosodium glutamate, the taste that is often a base in oriental dishes.

4 ODOURS THAT AFFECT US MORE THAN WE THINK To taste soup, at least one drop is needed that can be mixed with saliva to stimulate the taste buds. But the sense of smell does not need any drops to know that soup is being cooked in the house all that is needed is a few volatile molecules in the air of the room. A human being has a few million olfactory cells which are used to capture odours. A dog has 200 to 300 million, which partly explains why dogs have such a well-developed sense of smell. But the human tool for recognising smells is sufficient for us to identify and remember up to ten thousand odours. The olfactory cells reach into the part of the brain that is called the limbic system, the seat of feelings and memory. That partly explains why there is a strong connection between odours and memory. The fact that we are often affected by odours without being aware of them also means that we have not developed a way to describe them. This, in turn, is because the link between the sense of smell and the brain s language centre seems to be weak. Nevertheless, odours are very important for our well-being. In both humans and animals with a much better developed sense of smell, odours are an important part of our perception. In animals, the sense of smell is important in controlling procreation; in people this is perhaps not so pronounced even if our perception of other people s odours may be very strong. It is definitely a fact that we release odours that reflect our mood, even though humans lost the ability to consciously register such olfactory messages a long time ago. Any dog, however, can recognise the odour of a frightened human.

5 SENSES AND CHEMISTRY IN AN AROMATIC COMBINATION Rose blossoms on a summer s day. The leather of new shoes. Spices in the soup bubbling on the stove. We live in a world of odours and flavours. Gradually we develop methods to identify and describe them in a more scientific way than the poets do. But the dilemma of odour and flavour is that no matter how we refine our techniques for discovering and describing odours, different individuals perceive them in different ways. Our perception of odours depends on many subjective factors. Our general mood, our momentary concentration, our surroundings, our previous experience these are all factors that affect our perception of odour. Men and women may be sensitive to different odours; age is another variable, as are stress, personal situation, even the time of day. An uncomfortable experience in association with a particular odour may affect our reaction to it all our life, even if the correlation between the odour and the experience is not very rational. In other words, the perception of an odour is subjective and can vary from time to time. But we are also influenced by so much more. The visual impression of a dish of food and its consistency, for example, may also affect how we react to its flavour. A further complication is that different substances have different degrees of odour, and the concentration required for our noses to discover or recognise a substance varies greatly. Even worse three substances that separately have a strong odour may seem to smell less when they are mixed. More than a sensitive nose is required to distinguish the various elements. Since smell and taste have both chemical and sensory dimensions, we must work in both these fields when trying to add to our knowledge. A sensory analysis determines that something smells or tastes. A chemical analysis determines what it is that smells or tastes. These techniques must be combined in order to work systematically with questions of odour and flavour.

6 THE PACKAGER S DILEMMA A package must protect and preserve its contents. It must not add or remove odours or flavours from what it contains. There are laws to say that packages must not modify their contents, and the market especially makes demands on the properties of packaging. The more vulnerable the contents of a package are, the greater are the demands made on the packaging. Smell and taste affect packaging in different ways, usually described as one of the following: MIGRATION. Odours and flavours from the packaging material are transferred to the product in the package. FLAVOUR SCALPING. Odours and flavours from the product are transferred to the packaging material. PERMEATION. Odours and flavours from the surrounding environment pass through the packaging material to the product inside, and vice versa. These models do not suffice to describe entirely the complexity of what the packaging manufacturer or packager faces. A modern paperboard package consists not only of paperboard. In the package, paperboard, glue, printing ink, varnish, plastic coatings and foils must together form a rational package with sales potential. Even if all components have their own individual odour-neutral and taste-neutral properties, this may not be true when they are combined. The consumer does not care in the least whether the glue or the paperboard individually has a neutral odour. He or she wants the chocolate or other food in the package to be untainted. Therefore it is extremely important for all those who work in the chain of distribution between producer and consumer to be aware of the odour and flavour issue. This is especially true since odours and flavours are processed by our subconscious to such an extent. An off-taste in food may be so weak that few consumers, or none, make a complaint, but the result may still be reduced sales, or none at all.

7

8 L A B O R AT O RY F O R S E N S O RY A N D C H E M I C A L A N A LY S E S THE GUARDIAN OF GOOD TASTE Strömsbruk, Sweden, is the site of the Laboratory for Sensory and Chemical Analyses, part of the Development department, Iggesund Paperboard s centre of excellence for odour and taste. The laboratory carries out a number of tasks related to its specialist competence: PRODUCTION CONTROL TROUBLESHOOTING CLAIMS PROCESSING RESEARCH DEVELOPMENT Production control means that the laboratory analyses samples of incoming raw materials out of production. The pulp and the latex that is used as a binder when coating the paperboard are tested regularly. PE granules for plastic coating are also checked at the laboratory on arrival at Strömsbruk. Paperboard leaving production at Iggesund, Strömsbruk and Workington is inspected with reference to odour and taste. In the chemical analysis, ageing of the sample is simulated and the result is analysed using gas chromatography. This allows us to predict if a batch deviates from the normal grade and if there is a risk of unwanted odour or taste in the future. Gas chromatography, both hot and cold headspace testing, is used to register and identify the volatile substances released by the paperboard down to the smallest detail. In combination with a sensitive human nose, the intensity of substances is determined, the extent to which they smell and what the characteristics of the odour are. Claustro is a unique combination of measuring equipment and methodology which has been developed at the laboratory. With its help it is possible to study the simultaneous effect on packaging material of up to four aroma substances or their ability to permeate the material. Claustro gives packaging designers new possibilities of optimising barrier functions and thereby of creating even more appropriate forms of packaging.

9 EXPERIENCED NOSES For the sensory part of the tests, the laboratory has established a panel for odour and flavour testing. People are chosen for the panel who have a good ability to distinguish odours and flavours, and who also have the ability to translate their impressions into words. Over thirty persons are engaged in the panel, and it takes an average of one year to train a person s ability to the point at which he or she can become a fully participating member of the panel. Panellists take part in both odour and flavour testing. The tests are designed so that the individual panellist s precision on the particular day can be checked statistically. Because the panel can be calibrated statistically, the results from an individual who is not performing well that day can easily be spotted and isolated. In this way a high degree of reliability can be achieved. The Laboratory for Sensory and Chemical Analyses has been an accredited laboratory for sensory measurement since The accreditation requires absolute quality standards which are guaranteed and inspected by the Swedish Board for Accreditation and Conformity Assessment (SWEDAC). The accreditation is also a guarantee that tests and measurements are done objectively using approved and tested methods.

10 QUALITY AND KNOWLEDGE NOW AND IN THE FUTURE Iggesund Paperboard is Europe s leading manufacturer of high-quality paperboard for packaging. Our products are used to a great extent in the packaging of food and medicine fields in which the odour and taste properties of the paperboard are at least as important as other measures of quality. Thanks to a long-range emphasis on control, research and development, we are assured of our own quality and can also offer customers our unique knowledge. Copyright Iggesund Paperboard AB The cover is printed on Invercote Albato 250g/m 2. The inside pages are printed on Tom&Otto Silk 170g/m 2. Photo Rolf Andersson/Bild-bolaget, Jörgen Lorentzon/Studiobild, Vince Reichardt. Design and production Position. Print Gävle Offset AB.

11 CO05013E