Reference has already been made to the role that diet plays in the incidence of chronic disease (section 13.4.2). One of the major challenges to face the modern food industry is the need to develop products that can contribute to the customers' desire for a healthy diet and the additional benefits such a diet provides. Alldrick (1998, 2001) has previously discussed the general principles underlying the design and marketing of these types of products both in general terms and with specific regard to cereal products.
A number of foods designed to meet the consumers' aspiration of improving their health through diet might be described as 'Functional Foods'. Ichikawa (1994) defined these products as: 'Processed foods containing ingredients that aid specific bodily functions in addition to being nutritious.' A key point to remember about functional foods is that they are not medicines. Thus while health claims (e.g. 'as part of a low fat diet our product may help to reduce blood cholesterol concentrations') might be permitted, medical claims, in other words claims to the effect that the food could cure, prevent or alleviate a disease, are generally prohibited.
Over the last few years, an increasing number of cereal-based products have come onto the functional-foods market. Some have been marketed on the basis of elevated vitamin or mineral content. What has been more novel is the devel opment of products containing pharmacologically active compounds. One group of compounds that has attracted interest is the phyto-oestrogens. These are plant compounds which bear a structural similarity to the female sex hormone oestra-diol and fall into three broad chemical categories: isoflavones, coumestans and lignans. They are thought to have beneficial health effects with regard to cardiovascular disease, certain cancers and the menopause (Bingham et al, 1998). A number of baked products, for example breads containing soya, linseed and/or flax and with high contents of phyto-oestrogens, have been released (Dalais et al, 1998; Payne, 2000). These have sometimes been referred to as 'Sheila' breads, reflecting their Australian origin.
Arguably, however, the key growth area has been fibre-enriched products. These products may be enriched with cereal-based dietary fibre or fibre derived from other plants, for example psyllium. As discussed in more detail elsewhere in this book, dietary fibre has been shown, or is thought to be, beneficial in managing the risk of a number of diseases. From classical times (British Nutrition Foundation, 1990) the beneficial effects of cereal fibre and in particular insoluble fibre on colonic function have been known. More recent work, such as the meta-studies of Ripsin et al (1992) have demonstrated that soluble fibres may have beneficial blood cholesterol lowering effects, particularly when eaten as part of a reduced fat diet.
Within the context of this chapter, a fundamental aspect that must be addressed in the design, development and manufacture of any nutritionally enhanced cereal food, is that of functionality. Here the term functionality not only applies to achieving the desired physiological consequences of eating the food in question, but also to the way ingredients behave during processing, together with their effects on product attributes. In developing this type of product, therefore, two questions need to be addressed.
These questions can be best examined looking at specific examples using one particular physiologically active dietary component. Here the component discussed is dietary fibre.
The two questions raised above can be intimately linked, and in unexpected ways. For example, the introduction by the animal feed industry of 'High Temperature Short Time' (HTST) processing (e.g. use of expanders), particularly for poultry feed, in the early 1990s led to a reduction in feed efficiencies. This was related to an increase in the proportion of soluble dietary fibre in the feed and consequent increased viscosity of the animal's digesta (Sundberg et al, 1995). In the previous decade, it had been demonstrated that processing cereals in equipment such as expanders led to a solubilisation of the fibre component (Ralet et al, 1990). The degree to which this occurred was dependent on the energy input. The problem was overcome eventually by the addition of appropriate dietary-fibre degrading enzymes (Sundberg et al, 1995).
Although extreme, the above example does highlight the need to consider other physiological effects that may impact on the consumer. This can be in the form of unpleasant side effects, such as, in the case of dietary fibre, large bowel complaints such as flatulence (Bolin and Stanton, 1998) or impaired eating qualities in certain subgroups of the population, such as the elderly (Laurin et al, 1994). A simple moral can be derived from these examples. Failing to have a detailed understanding of both the links between the effects of food processing on the physiologically functional ingredient and all of the roles played by that ingredient on the consumer's physiology and/or sensory expectations can be prejudicial to the product's commercial success.
In addition to the needs of the customer, any new product design process must also take into account the need for the product to be compatible with existing manufacturing technology. This is particularly true for high dietary fibre products. One such example is the manufacture of wholemeal (100% extraction) flour bread using 'no-time' dough making processes (e.g. Chorleywood Bread Making Process). Studies performed at the Flour Milling and Baking Research Association (Collins and Hook, 1991) have demonstrated that production of a loaf with those characteristics preferred by the consumer is dependent on a number of parameters. Particle size distribution within the flour was important not only for baking quality but also for the overall appearance of the crust and crumb. Addition of dried gluten protein was found to be a suitable method for improving hedonic parameters including loaf volume and crumb-score.
Increasing the content of a physiologically desirable component within an existing product can have consequences with regard to the behaviour of intermediate products and/or the appearance of the finished product. Work with bread containing elevated amounts of dietary fibre has shown that the addition of extra dietary fibre could lead to changes in dough rheology and handling characteristics as well as product appearance and texture (Pomeranz et al, 1977; Laing et al, 1990).
In marketing any cereal product with enhanced physiological benefits, it will be necessary to ensure that the product contains sufficient active ingredients to meet local regulatory requirements. However, it will also be important to ensure that the food is physiologically functional and has acceptable sensorial properties. Any advertising campaign for the product should be, 'legal, honest and truthful' (Advertising Standards Authority, 1999). Enthusiasm for the product should not be allowed to diminish the accuracy of advertisements. The functional foods area is a growing market. Young (1999) valued the European market at USD 1.24 billion in 1997, with bakery and cereal products commanding a 9% share. Consequently, functional foods also attract attention from consumer protection groups. Winkler (1998) reported that during the period 1994-1997, the UK Advertising Standards Authority upheld 21 complaints concerning advertisements for functional foods.
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