11 Flavours and spices 11 .I Introduction The flavour of a food is the combined effects of taste, smell and mouthfeel. The taste is the combination of sensations perceived by the tongue and these are limited to sweet, sour, salty and bitter. The smell is the sense by which certain properties of volatile substances can be perceived on the sensitive membranes in the nose. The mouthfeel is the tactile sensation created in the mouth when a food is chewed or dissolved combined with the tasting and smelling sensations. The acceptability of a flavour is also complex. The human brain has an amazing memory for tastes and smells and can recall not only what, but often even where and when, it was previously exposed to them. For example, there are some wine tasters that claim they can identify a wine to a particular vineyard! Thus, when a consumer is tasting a biscuit it is important that their identification of the flavour is a ‘satisfactory’ experience. 11.2 Sources and types of flavour The largest group of flavours originate from plant materials, usually the fruits or leaves of plants. Others come from cooking and these include the crust flavours (associated with the Maillard reaction between amino acids and reducing sugars), burnt flavours and roast flavours which include those from meats. For biscuit manufacturing it is important that flavour ingredients are convenient to use and of standard strengths and qualities. To provide such substances is the challenge for the flavour ingredient industry. 64 Flavours and spices 65 11.3 Spices and herbs These are a basic and valuable source of flavours. The distinction between a herb and a spice is a bit vague but it is commonly considered that a herb flavour accompanies a savoury or non-sweet food and a spice a sweet product. Parts of plants are collected, dried and ground to form a strongly aromatic powder which can be used directly in or on a food. Many of the plants involved grow in tropical countries and it should be remembered that the hygiene conditions associated with harvesting, drying and storage may not be good. Where these materials are to be used in foods which will not be heated to sterilise them it is possible to purchase special grades that have been checked for microbial contamination. Ground herbs and spices carry the aromatic elements in the cells of the plant tissues. The finer the material is ground the more of the flavour is released and will evaporate during storage. All powdered spices and herb materials are particulate and will affect the colour of the product in which they are used. 11.4 Essential oils An essential oil is a volatile mixture of organic compounds derived by some physical process, for example, distillation, expression or solvent extraction, from odorous plant materials. A specific oil is derived from one botanical species with which it agrees both in name and odour. The most commonly used essential oils in biscuits are the citrus oils from lemons and oranges. 11.5 Oleo resins These are solvent-extracted compounds remaining when the solvent has been evaporated. They are very concentrated and often caustic, even more caustic than some of the essential oils. Some commonly used oleo resins in biscuits are bun spice and ginger. As ol& resins are very concentrated they are often treated to form solutions or powders. 11.6 Synthetic flavours-GRAS By sophisticated chemical analysis it is possible to identify the individual compounds that make up a particular scent or flavour. It may be uneconomic to extract the flavour element from the original 66 Biscuit, cookie and cracker manufacturing manuals source but chemically synthesised ingredients can be blended in the same proportions as were found in the natural flavour. Flavours made in this way are described as ‘nature identical flavours’. The inference is that natural flavours are safer than concoctions made up by a flavourist from a library of aromatic chemical compounds but logically this cannot be the case. The chemicals used for flavours must have an acceptability for use in food and the term Generally Accepted As Safe (GRAS) is frequently seen in connection with synthetic flavours. It will be appreciated that there is a never ending possibility of flavour blends that are possible from the various synthetic and natural flavour compounds available to the flavourist. 1 1.7 Other flavouring substances In addition to the broad groups described above there are many other substances commonly used to flavour biscuits. Examples are cheese powders, dried autolysed yeast, dried meats and extracts, vegetable protein hydrolysates, dried and diced nuts and fruits. 11.8 Form of the flavouring material Ground spices and herbs are obviously powders of varying granularity. Extracted oils and most of the synthetic flavours are liquids. Oleo resins are naturally liquids or viscous pastes. It is important that the flavouring material is at a concentration and in a form that is suitable for the application. Liquids can be diluted with a suitable solvent, commonly used solvents are alcohol, propylene glycol, vegetable oil or water. Liquids can also be made into powders by adsorbing them onto salt, rusk or dextrose, etc. The powders can then be weighed, dusted or premixed in a more satisfactory way than small quantities of liquid or paste. It is also possible to microencapsulate liquid flavours with a vegetable fat of suitable melting point. The process is expensive and, at least, for biscuits this form of the flavour is not commonly used. 11.9 Flavouring of biscuits If we concern ourselves principally with the introduction of aromatic ingredients as a contribution to flavour it can be seen that biscuits and other cooked products may be flavoured in three principal ways: Flavours and spices 67 1 By including the flavour in the dough or batter before baking. 2 By dusting or spraying the flavour after baking. 3 By flavouring a non-baked portion such as cream filling, icing, jam or mallow which is applied later. The conditions experienced during baking are very severe for aromatic compounds. They are easily removed by heat because, by definition, they are at least slightly volatile at mouth temperatures. In general, liquid flavours are not to be recommended in baked products especially those with doughs containing high levels of water such as crackers and hard sweet types. Some means of protection is needed and the sealed cells of plant tissues are somewhat successful in this. Thus, ground ginger is better than a liquid ginger extract. There are some flavours that are found to be better than others in baked products; notable are vanilla (or synthetic ethyl vanillin), butter, cheese, almond essence and roasted materials like chocolate, coffee, caramel and also smoke flavours. Flavours that are protein based such as hydrolysates are more stable to baking temperatures but can be drastically changed if even slightly burnt. Cheese is an example of this. Spices generally survive baking better than blended flavours or extracts. 1 1.10 Flavours applied after baking These can be of any type but more savoury types find use in this area than flavours associated with sweetness. The flavours may be dispersed on a cereal or dextrose base and dusted onto an adhesive surface, like an oil film, over the product or sprayed on as a solution in edible oil. Either way the system tends to be messy and cause strong odours in the vicinity. The techniques generally are not ideal for products like biscuits, which have lower surface areas for a given weight than potato crisps or extruded snack products. 11 .I 1 Normally, essential oils and other liquid flavours find their best use in these components of biscuits. Advances in the flavour industry have resulted in excellent reproductions (or nature identical Flavours in creams and jams 68 Biscuit, cookie and cracker manufacturing manuals mixtures) of fruit, nut and other exotic flavours and their use in non- heated parts of a product are in general extremely successful. Points to remember in the use of flavours in these situations include: 1 The acidity and colour of the base is of great importance to the acceptance of the flavour when eaten. 2 The correct strength is important. Often there is a saturation level to the taste. Conversely, too great a concentration may result in lingering and unpleasant aftertastes. 3 The texture of the base, especially if it is not readily soluble in water is most important. The dispersion of the flavour if it is a powder must he watched. 4 Acids, flavour enhancers, sugars or salt should be of the correct particle size to allow correct solution speed in the mouth relative to the sensation given by the flavour compounds. 5 Where fats form an important part of the product, as for example, in biscuit creams, melting characteristics must be matched to body temperatures and ambient conditions to allow optimum flavour release on eating. 11.12 Flavour enhancers These fall into two main groups, simple salts and acids that on their own are relatively unacceptable, and complimentary ingredients or colours that enhance the suggestion of the flavour. The most important flavour enhancer is common salt. Used at about 1.0% of the flour weight, salt has a remarkable enlivening effect on most flavours, it may also be used in chocolate and biscuit creams. Monosodium glutamate (MSG) is a commonly used savoury flavour enhancer. This chemical is usually purchased in a fie white crystalline form. It is readily soluble in water and should be used at a concentration of about 0.5% of the product weight. For fruit flavours, sugar or some other sweetener, is an important complimentary ingredient. An excellent strawberry aroma tastes very strange, for example, on a bland non-sweet base. Also, nearly all fruits are relatively sharp in taste, the sharpness derived from the naturally occurring fruit acids (see Section 12.6). Flavours and spices 69 11.13 Storage and critical quality points By definition, all flavours are at least partially volatile. It is therefore important to store them in a sealed container, away from light, heat and oxygen that may cause some degradation. Flavour may decay with age so minimum stocks should be held and stocks that have been opened and held for more than about two months should be sampled and tasted against a control. As a matter of standard procedure a sample should be taken from a delivery and checked against a control sample. The control sample can be stored in a dark bottle in a refrigerator but be sure to compare a new sample with the control at the same temperature.