Doctoral Training Partnerships: a range of postgraduate training is funded by the Research Councils. For information on current funding routes, see the common terminology at https://www.ukri.org/apply-for-funding/how-we-fund-studentships/. Training grants may be to one organisation or to a consortia of research organisations. This portal will show the lead organisation only.

According to the World Heath Organisation, obesity has more than doubled since 1980. Estimates suggest that obesity now affects around 1.5 billion people. This is worrying because the health and economic consequences are very clear. Obesity is a major risk factor for cardiovascular diseases, diabetes, and some cancers. One of the key observations about obesity is that not everyone becomes obese, even when they live in the same community, or even the same family. This means that some people appear to be 'protected.' Obesity researchers are interested in understanding why this is the case because this protection may hold the key to an effective treatment, or even a way to prevent obesity in the first place. For a long time, researchers and health professionals have suspected that obesity is associated with a particular eating style, eating quickly in particular. Indeed, it is sometimes said that we should chew our food several times in order to feel satisfied and to 'aid digestion.' Recently, researchers have begun to explore this idea systematically. The results are striking. For example, under controlled conditions, it would seem that eating at a slower rate produces both an increase in self-reported fullness and a reduction in meal size. Moreover, when we look at people across an entire country, we find that eating rate is a good predictor of bodyweight, even in large-scale studies. In 2010 researchers started to look at ways to reduce eating rate to see if this might be used to lower bodyweight. Their results were impressive. They used device called a mandometer to encourage children to eat at a slower rate. This training produced a clinically significant reduction in bodyweight, which was sustained 12 months post treatment. The prospect that we can manipulate eating behaviour to reduce energy intake is tantalizing because this approach has potential as an effective treatment for obesity. Moreover, an opportunity exists to change our eating behaviour by manipulating the physical characteristics of food. If this can be achieved then we may be able to design foods to encourage behaviours (e.g., slow eating) that reduce our calorie intake from meal to meal. Importantly, for these benefits to be realised, we need to discover the underlying mechanism. This is an important objective of this project. In the first instance we will develop a method to quantify and characterise 'eating topography' - collectively, the pattern of behaviours associated with eating; swallow rate, bite size, eating rate, and so on. With this tool, we will run a series of experiments to identify specific aspects of eating topography that influence our food intake. In a second set of experiments we will focus on the mechanism. Two hypotheses will be tested. Firstly, we will explore the prospect that a causal relationship exists between specific aspects of eating topography and the hunger and fullness that we experience at the end of a meal and during the period between meals. There are two reasons why this relationship might exist. Eating topography may change levels of hormones that control our appetite. Alternatively, it may influence the formation of memory for a meal - a process that is known to influence the amount of food that we eat at a subsequent meal. Our second hypothesis relates to the eating topography that is associated with particular foods. If a food is eaten with a topography that makes us feel full then we may remember this relationship. In future, when we encounter that food again, we may expect the food to be more filling and select a smaller portion. By this account, eating topography influences our energy intake by changing the way we make decisions about portion size, before a meal begins.

Chocolate represents a structured material with a continuous phase of crystallised cacao butter in which sugar crystals, non-fat cocoa solids and milk solids (in case of milk chocolate) are dispersed. In its molten state chocolate can be described as a suspension containing several dispersed, solid phases which affect the flow behaviour with their volume fraction, specific size, shape and surface property characteristics. In conventional chocolate the fat content, is about 30 %wt which equates to a dispersed phase volume of solids of about 0.45. Decreasing the fat content, i.e., increasing the dispersed volume fraction, to obtain a less calorific chocolate is not a viable option since the accompanied increase in viscosity of the chocolate in its molten state will impact negatively on the processing behaviour and sensory characteristics . However, it is possible and has been demonstrated, to modulate the particle size distribution to achieve more efficient packing of the particles and, hence, higher volume fractions without affecting the viscosity behaviour to an undesirable extent. The drawback of this approach is that particles above the generally accepted size limit above which grittiness tends to be observed during consumption is well exceeded. Other methods such as substituting the fat phase by a water-in-oil emulsion, use of fat replacers such as Salatrim for 'direct' removal or replacement of fat, and the use of increased emulsifier levels including emulsifier blends to allow for an increased solids content by increasing interparticle lubrication to maintain an acceptable viscosity level, have sensory properties or consumer acceptance negatives associated with them. In this industrial case project we propose investigating innovative approaches for the dispersed phase design to formulate low calorie chocolate hypothesised on overcoming the limitations outlined above. Initially, we will build on our previous work on modulating the particle size distribution of the filler phase by introducing a novel soft solid filler phase. It is hypothesised that the grittiness threshold for solid filler particles does not apply to soft solid particles. This needs to be tested. The type of soft solid particles we propose introducing are hydrocolloid or protein based dry particles that swell and become 'soft' in mouth. This may be achieved with conventionally available material, or powders that have undergone extrusion processing for physical modification. For example, for a conventional xanthan gum requiring high shear input for dispersion and subsequent dissolution in water, it has been shown extrusion processing imparts a rapid swelling and dispersing characteristics. In this project we propose exploring whether extrusion in a lipophilic phase that may or may not be miscible with cacao butter will produce swellable soft particles. A further novel filler phase that may be introduced into chocolate is a second non-aqueous liquid phase which may or may not need stabilisation by suitable emulsifiers. In its molten state the chocolate then will have a dispersed droplet phase and a dispersed solid phase, i.e., it will be a hybrid between an emulsion and a suspension. We will study the rheological behaviour of such a material, which has scarcely been reported, based on a simplified chocolate model system. Finally, we will investigate whether the non-fat cocoa solids phase has potential for exploitation. There is a lack of understanding of the role non-fat cocoa solids play from a material science point of view which will be addressed. With an enhanced understanding, suitable, preferably physical, modifications may become obvious that will contribute to the design of an improved low calorie chocolate based on dispersed phase innovation design.

Doctoral Training Partnerships: a range of postgraduate training is funded by the Research Councils. For information on current funding routes, see the common terminology at https://www.ukri.org/apply-for-funding/how-we-fund-studentships/. Training grants may be to one organisation or to a consortia of research organisations. This portal will show the lead organisation only.

Doctoral Training Partnerships: a range of postgraduate training is funded by the Research Councils. For information on current funding routes, see the common terminology at https://www.ukri.org/apply-for-funding/how-we-fund-studentships/. Training grants may be to one organisation or to a consortia of research organisations. This portal will show the lead organisation only.