Product reformulation has become a driving force in many manufacturers’ development strategies. Consumers seeking new taste experiences, adopting flexitarian eating habits or choosing sustainable brands are just some of the recent trends influencing new directions. Factor in the added pressure of high-profile health initiatives - such as achieving the 20% sugar content reduction target content set by Public Health England - and it’s not surprising that revamping product portfolios remains firmly on the agenda.
From a technical perspective, however, any change to a product’s formulation can’t be viewed in isolation. Such is the inherently complex nature of product recipes, processing and packaging regimes that an adjustment in just one ingredient can potentially impact any number of product characteristics; from texture and flavour to stability and flow behaviour.
That’s why it is so important to take a holistic view; where every aspect of the impact of the specified ingredient is analysed and understood in the context of the overall product concept, so that any necessary adjustments measures can be taken to ensure consistently positive product performance.
In the world of health and wellness, redesigning products to align with the latest trends is nothing new. But for formulators focused on creating the required nutritional profile or integrating the latest fashion-forward ingredient, understanding how these changes impact overall product quality is essential.
The replacement of highly saturated fats with mono- and poly-unsaturated alternatives has long been supported on health grounds due to their associated benefits with heart and brain functions. In addition, palm oil has come under scrutiny recently due to environmental concerns which has accelerated moves to find sustainable or completely different sources across food applications.
Whatever the rationale for reformulating with lower saturated fats, consideration must be given to two important effects.
Firstly, let’s consider the physical properties of the food. Fat provides a number of functional properties during processing and in the final product, which are dependent on the physical properties of the fat. Unsaturated fats, such as rapeseed and sunflower oil, have a lower melting point and are therefore more liquid at room temperature compared to their saturated counterparts. In bakery products for example, this may require changes in the formulation and process to compensate for the inability to cream liquid oils with sugar during cake making.
Other applications may also need attention. Cereal bars, for example, can appear greasy as a result of oil moving within the food matrix and migrating to the surface, while the use of a softer fat in the creamer in powdered beverages may cause the product to clump and not rehydrate as easily.
Secondly, let’s consider rancidity. Caused by the oxidative deterioration of unsaturated fats in foods, this is one of the major causes of quality deterioration in foods and is marked by unpleasant odours or flavours. Highly saturated fats have a greater resistance to oxidation, so replacement with unsaturated oils will reduce this effect and consequently shorten the shelf-life of the product.
These reformulation issues can be addressed using advanced techniques designed to evaluate the potential impact on product quality and organoleptic characteristics. A Thermal Desorption Unit (TDU) GC-MS, for example, can be used to measure the individual compounds that are responsible for giving the rancid off-notes caused by oxidation of the products. Analysing lipid oxidation markers at concentrations which extend below the perceivable sensory threshold levels for off-odours and off-tastes (in the parts per billion (ppb) to parts per million (ppm) range), enables the early stages of oxidation to be monitored.
In addition, because the TDU method does not involve sample extraction it can be applied directly to both raw ingredients and finished products. This end-to-end evaluation not only improves consistency of results, but is also much quicker than traditional techniques and an ideal way to monitor the oxidation of fats within food over time.
When it comes to reformulating products containing vitamins and minerals, the main problem formulators need to address is stability. Many factors can affect whether vitamins (and any other active ingredients) can survive in the product up to its proposed use-by date. These include the presence of oxygen, light and other vitamins. Even minor modifications to the formulation can have a major impact.
In practice this means that any changes to a fortified product - such as the introduction of a new botanical - can cause interference with the vitamins already present. As a result, the original methods designed to validate their presence in the matrix can be rendered ineffective. This clearly has major implications for brands in terms of labelling and on-pack claims substantiation.
Boosting the nutritional content of a protein shake, for example, may mean that one or more vitamins in the formulation can no longer be analysed using the original extraction method - despite having previously been successful in validating both shelf life and label claims. Similarly, expanding an established beverage range with the introduction of a different flavour can sometimes cause similar interferences. The flavour may degrade over time and the degradants may impact on the original analysis process so that it is not able to accurately quantify vitamins in the new product - even though this aspect of the formulation has not been altered.
Changes may also be made to the vitamin format. A move from liquid to encapsulated, for example, may be deemed advantageous in terms of improved solubility or product stability. But again, such steps could impact on the analysis of the vitamin in the product; the method may no longer be fit for purpose and result in the need to optimise the extraction procedure of the analytical method in order to support label claims.
One of the hottest food trends of recent years, the plant-based revolution shows no signs of slowing and product developers are naturally keen to capitalise on this growing market. Achieving a formulation with the desired characteristics, however, is often not an easy task and requires a high level of technical expertise due to the inherent problems associated with these ingredients.
Using plant proteins in place of dairy sources, for example, in a bid to appeal to growing vegetarian and flexitarian audiences raises issues of texture and flavour. Soya and pea are well-known for their distinctive taste and careful selection of the cleanest tasting protein source together with flavour masking may be required to optimise acceptability. Some of the newer proteins on the market can be even more challenging in this respect and some bring the added issue of a visually unappealing colour.
Gritty sedimentation caused by the lower solubility of these plant protein ingredients may also be an issue, but this can be minimised by modifying any hydrocolloids present to improve suspension and create the desired creamy texture - a measure which is particularly important in beverage applications.
In addition, the lower quality of some plant proteins compared to milk based options - as determined by the PDCAAS method of evaluation which assesses both the amino acid profile and digestibility - means that different sources may need to be blended together to achieve the required protein profile. For example, in sports nutrition products, this may translate to a formulation containing a careful combination of three different plant proteins; pea protein (high in lysine but low in cysteine and methionine) with rice and oat proteins (low in lysine but relatively high in cysteine and methionine).
Indeed, this ability to draw on specialist ingredients expertise is vital when working with different sources and types of plant protein; each of which has individual characteristics which must be understood in the context of each application, so that compensatory steps can be taken to create a well-balanced product.
With so much attention focused on plant-based ingredients, keeping pace with developments in order to capitalise on emerging trends requires an agile approach to formulation. New ingredients, come with new challenges which need to be understood. One of the most recent examples is CBD oil. Although its use in food and drinks has not yet secured regulatory approval, this hemp derived extract is already gathering momentum as some manufacturers seek to make the most of consumer interest by incorporating CBD flavours into beverages.
This is just one emerging trend but it demonstrates the need for product developers to be able to adapt formulations - and underlines the importance of having access to technical specialists capable of developing analytical methods to target novel ingredients.
Formulating a strategy
Of course, reformulating a product can also lead to new challenges in the manufacturing process. Understanding how the modified product is likely to behave under existing processing conditions is a critical part of any development project.
Any problems in terms of texture, taste, appearance or quality, resulting from changes to the formulation, will need to be resolved at key points in the production process. For example, changes may affect:
- Flow behaviour: Due to a difference in particle size distribution or moisture absorption. A liquid oil, for example, would reduce viscosity in a cake batter. Solutions may include measuring flow powder behaviour and tailoring the design of common equipment such as silos, hoppers, dosers and screw feeders
- Product caking and re-crystallisation: Potential risks of this unwanted phenomena can be identified and prevented using techniques such as Dynamic Vapour Sorption (DVS) which investigates moisture absorbance of powders - and so helps to determine critical processing and relative humidity. Sugar and salts are also important ingredients for regulating free water
- Shelf-life: The evaluation of water activity on a formulation over time or in conditions that accelerate aging can be used to estimate the shelf life of the new formulation. Knowledgeable selection of ingredients can also help to prevent rancidity, such as the use of sugar and hard fat in cereal bars.
Only by building a detailed picture of the many factors involved with the production of a reformulated concept - from manufacturing to distribution, storage and use by the consumers - can developers be confident that the repositioned product will deliver on every level. A strategy which requires an extensive range of scientific techniques and expertise in order to ensure an efficient development process.
Originally published by Nutraceuticals Now, April 2019.