Functionality, flavour and colour are only a few of the obstacles that could limit the viability of this sector. L Steven Young, PhD, surveys packaging, functionality, nutritional efficacy and cost considerations
Beverages offer unique fortification opportunities. These include ease of use, convenience, multiple types and formulation variety, packaging and manufacturing options, choices of distribution conditions, and relatively large serving sizes (g or ml per serving basis) compared to other foods. Given this latter fact, a small per cent use of any dietary-fibre ingredient could potentially deliver more than just a significant amount of dietary fibre on a per serving basis. To do this requires balance of nutritional efficacy; use rates; consumption need; manufacturing and packaging options; formulation needs; and retention of appealing sensory attributes such as visual appeal, viscosity, flavour and mouthfeel.
Select dietary fibres can function to allow formulation of fibre-enhanced beverages of virtually all types. Beyond simply adding dietary fibre to achieve 'good' (2.5g/serving dietary fibre), 'excellent' (5.0g/serving), or 'enhanced' levels (>5.0g/serving), beverages can take advantage of the nutritional efficacy of dietary fibre that can typically include structure/function claims and some qualified health claims ranging from low-glycaemic to healthful serum lipid levels.
There are many key considerations when selecting a dietary fibre for use in beverages. These include:
- Solubility: Simply, dietary fibre can be soluble or insoluble. It is pretty obvious that your first selection of any given dietary fibre should be based on solubility of not only the dietary element but all components of any given ingredient.
- Dietary-fibre content: The higher the per cent dietary fibre, the less ingredient need be used. This becomes critical relative to function (eg, retaining refreshing viscosity) and stability (eg, maintenance of dietary-fibre content).
- Flavour and effect on flavour: As with colour, dietary fibre for beverages should not have any inherent flavour or effect added or naturally occurring flavours.
- Viscosity and effect on viscosity: Because beverages feature low-to-mid-range viscosities and also may require controlled viscosity, any given dietary-fibre ingredient should have minimal or no direct or indirect effect on viscosity.
- Use rate: Use rates can be determined with great specificity. Becuase many times a packaging or other claim is to be made relative to the amount and/or type of dietary fibre used, typical use rates reflect directly back to the specific claim to be made and the relative amount of dietary fibre in any given ingredient.
- Labelling: With multiple sources of dietary fibre available, choices for ingredient declarations also vary. Common and usual name(s) for any given ingredient must be used, but creating an ingredient statement that is both consumer friendly and scientifically correct, and reflects directly to nutrition facts statements is also important. Disconnects between ingredient statements, nutrition facts panels and claims are not all that uncommon.
- Stability to applied processes: Dietary fibres are typically indigestible carbohydrates. However, they may also not be stable to formulation chemistry, thermal processes or distribution abuse in the final beverage. What this means is that breakdown of any given dietary fibre could result in loss of dietary-fibre content and an increase in lower molecular weight sugars across formulation, processing and distribution. This can limit shelf-life expectations so that nutrition facts are correct and no adverse nutritional effects are passed to any given consumer. In instances where dietary fibre is not stable, shelf life is determined based on when the beverage fails to deliver the compositional or nutritional claim(s) being made.
- Cost: As with all foods, costs impact all that we do as food technologists. Cost per kg of ingredient is not the whole story and it is highly recommended to consider cost per unit of dietary fibre and, then, cost per unit of finished beverage.
There are more than 60 dietary fibres on the market, with more being commercialised daily, so selection of the right ingredient for the right purpose can be daunting. Composition (soluble and insoluble dietary fibre) is critical, as are minor constituents such as sugars, fats/oils, proteins, salts, etc., that could limit utility of any given ingredient (See Table 1). Functionality is measured in terms of water binding, flavour, colour and texture of not only the ingredient itself but also how that ingredient affects the functionality of the finished beverage. As beverages have specific functionality needs, not all dietary fibres may meet the specific needs of any given beverage.
Dry mix formats. Flavour, colour, solubility and dispersibility of all ingredients and the final blend can be critical to success.
Ready-to-drink (RTD). Room temperature distribution and ultra-long shelf lives are typical requirements of these type beverages. RTD formats can be executed in a number of ways both single strength or as concentrates.
Drink concentrates. Depending on need, drink concentrates can be made by creating systems to which water would be added to create single-strength beverage. Essentially, technical considerations in formulating and delivering drink concentrates are much the same as for single-strength beverages.
Still. 'Still' beverages do not have added carbonation to provide both effervescence and microbiological stability. Thus, without carbonation, these beverages must be formulated and processed to meet the demands of either refrigerated or room-temperature distribution.
Carbonated. Carbonation provides not only mouthfeel refreshment but also stability to limit and control microbial growth. Carbonation must be done with ultra-clean ingredients and pre-treated water (low microbiological counts and free from pathogens). If pHs are not sufficiently low enough, ingredients that help control microbiological growth may be necessary.
Retorted. Beverages, particularly low-acid beverages (> pH 4.6), can be rendered commercially sterile by applying appropriate thermal processes to retortable metal cans or glass. This is the same process as used for canned foods. Times and temperatures are long and high, respectively, putting pressure on proper selection, stability and performance of any given dietary-fibre ingredient.
Pasteurised. If a formula is a low acid food (> pH 4.6), then pasteurisation followed by refrigerated packaging and distribution is an option. Because pasteurisation is effective and mild, sensory properties can be retained but shelf-life expectations are relatively short and distribution is costly.
Extended shelf life (ESL). ESL applies ultra-high temperature (UHT) processing well beyond simple pasteurisation to allow extended shelf life from a few weeks to a few months depending on formula, process, and packaging and supply-chain conditions.
Aseptic. Using UHT thermal processing and packaging under sterile conditions and retaining the beverage as sterile can extend beverage shelf life to 12 months (or more) at room temperature. Again, this all depends on the specific nature of the beverage and how termination of shelf life is defined. Although room-temperature distribution is desirable, cost of UHT/aseptic execution can be high.
Shelf life of any given food, including beverages, is defined for each formula made and packaged a specific way and distributed under specific conditions. End of shelf life will depend on what key feature of the beverage fails first. This could be colour, flavour, viscosity, mouthfeel, fortification levels and more. In beverages, dietary fibre must be stable to all applied processes and supply-chain demands. If not, the fibre content will decline (many times with an increase in simple-sugar content, sweetness, browning and other undesirable attributes) with time, and end of shelf life could be determined by failure to maintain any given dietary-fibre claim. Key consideration of this will determine which dietary fibre to choose.
The cost of dietary-fibre ingredients, of course, depends on availability. The per- unit raw-material cost is important but does not tell the whole story. In most applications the dietary-fibre cost per unit and/or the functionality cost per unit should be considered. In fibre-enhanced beverages where dietary fibre may have little functional importance, the dietary-fibre cost per unit is most important. Many times, raw-material costs may seem excessive, but the dietary-fibre cost per unit may, in fact, be the lowest-cost option. Care is necessary when considering costs, but extremely critical to success.
Key ingredient functionalities necessary to take into account include colour, flavour, particle size, density, solubility, contribution of food structure, dispersibility (or lack thereof), water binding (moisture retention), sugar content, fat content, calorie content, and effect on overall shelf life and acceptability.
A number of formulation approaches can be applied. Much is determined by what the finished beverage is to be, what needs to be said, process/packaging options selected, and distribution abuse expected. Table 2, above, demonstrates one such concept. (For five different concepts, from relatively simple to more complex, visit www.ffnmag.com) Certainly, use of multiple dietary fibres is allowed, but again, only if ingredients of choice are compatible with the beverage formula, its processing and each other.
Matching science with claims
Adding dietary fibre to beverages is desirable, and demand for these products is real and sustainable. Claims and opportunities are market and applications dependent. The utility of any given dietary-fibre ingredient is a function of its flavour, colour, performance and cost. Not all dietary fibres are meant for all beverage applications. Combinations of dietary-fibre ingredients are fine and many times desirable to overcome individual limitations of use. However, in all cases the dietary fibre(s) of choice must first be compatible with beverage type, processing options, desired packaging and supply-chain demands. It is critical to match the specific beverage execution, dietary fibre and use rates with available sound nutrition science. Matching science with any appropriate claim to be made can help a formulator get to the finish line more efficiently and more accurately.
Finally, it is all about flavour and taste. However, matching product features (facts) to consumer benefits (reasons to buy) across the entire intended shelf life of any beverage is critical to ultimate product development success and to the ultimate good of providing consumers the fibre they need.
L. Steven Young, PhD, is principal of Steven Young Worldwide in Houston, Texas, a technical and nontechnical consulting firm specialising in the development and use of novel new food ingredients. www.stevenyoung.net
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