Copy of Self structuring foods with slow burn for control of satiety

Lead Research Organisation: University of Birmingham
Department Name: Chemical Engineering


There is a need to control energy intake of consumers. A problem is that foods have become softer and more easily digestible and are less satiating. This leads to the individual feeling hungry more quickly and wanting to eat again often between meals. It has to be recognised that the consumer however, wants to have foods that are convenient, good tasting and easily prepared. The technical need is therefore to find ways to structure the food so that it is stable during storage and distribution is convenient and tastes good but then is slowly digested resulting in calories being released over hours. One potential way of achieving this is to produce foods that respond to the environment they find themselves in. So a food that is structured with a hydrocolloid that is sensitive to pH and is designed to structure the contents of the stomach (e.g. forms a gel that occupies the whole stomach) is potentially capable of slowing the stomach emptying process. Initial work has shown that this is possible and that the onset of hunger can be delayed by several hours. We intend to extend these initial findings and produce and investigate a range of alginates to control the gelation rate and gel properties under conditions; acidity, salt, temperature corresponding to the stomach. Having developed an understanding of the fine structure control of alginate we will study alternative materials that are acid sensitive (eg pectin, gellan etc) as well as investigating mixtures of these materials with each other and non acid sensitive hydrocolloids for specific kinetic and rheological control. There is a requirement to have temperature and time stable structures so that they can be transported and used in cooked products so we will investigate the use of sheared gels. A significant challenge will be to have materials included that will modulate the energy delivery and slowly release calories after the meal (slow burn) and still be organoleptically acceptable to the consumer. In order to do this we will include starch in different states; which are known to be digested at different rates and so delivers energy to the body over different timescales from minutes to hours. Starch which is highly crystalline can result in sandy or gritty textures in the mouth, particularly as the retrogradation process is not controlled in the manufacturing process. This has in the past limit the applicability of controlling energy release in soft foods using retrograded/resistant starch. We will investigate ways of including starch in other biopolymer and sheared biopolymer systems including 'hydrocolloid shells'. The shell will be designed to protect the starch against the amylase in the mouth and slow down the acid action in the stomach. This may well require a double or even triple shell to be produced with different hydrocolloids making up the shells. The overall dimensions of the particles will be less than ten microns to avoid oral detection. In addition, starch in plants is more slowly digested than raw starch and we will investigate the separation and inclusion of cellular materials that are texturally and orally acceptable. Having investigated routes to obtain self assembling structures and the way to include and modulate breakdown to control calorie release, we will then use our engineering skills to find ways to produce these materials at scale. As we do so we will be aware of potential problems of use in storage and transportation i.e. breakdown of the structures at elevated temperatures or self structuring occurring on storage before the product is used by the consumer. We will develop cyclised hydrocolloid networks, fluid gels (ie calcium cross linked alginate) which are temperature and time stable but dissolve at acid pH's and restructure into acid gels in the stomach. Fluid gels will be constructed by gelling the hydrocolloids or mixed hydrocolloids under well controlled flow fields and temperature profiles eg temperature ramped turbulent flow.

Technical Summary

The project is to construct foods (components) that are sensitive to environmental change and will self structure in the stomach. The gel strength and rate of gelation need to be controlled to gel the majority of the stomach contents and then de-assemble over a period of hours to allow stomach emptying to occur over 5 to 6 hours. The acidity of the stomach will be used as the major trigger for self assembly of a number of polysaccharides (eg alginate, pectin, gellan) and proteins (milk, vegetable). These hydrocolloids are families of molecules and the fine structure of the polysacarides will be selected from different sources or manipulated (eg by enzymes) to give increased or decreased acid sensitivity and manipulate the rates of gelation and the final properties. Combinations of these hydrocolloids will be used to control gelation and gel properties by modifying the phase sense and the phase volumes in the de-mixed systems. In order to make these materials compatible with soft foods and to stabilise them for storage and use we will investigate routes for production of fluid gels based on these self structuring systems ie investigate the use of calcium stabilised alginate fluid gels that are additionally capable of acid gelation so that the fluid gel breaks in the stomach and the released hydrocolloid then forms a bulk acid gel. Having developed ways to gel stomach contents and slow empting process we will encapsulate starch in different formats; crystalline, partially hydrated grains or dispersions, into hydrocolloid shells, emulsion droplets or intact plant cells, so that starch digestion is stopped in the mouth and starch has to be digested in the stomach. The encapsulate will be carefully selected to modulate the rate at which digestion occurs so as to release calories over the time period between meals. We will then investigate ways to produce the self structuring and slow burn components at pilot scale and incorporate them in a demonstrator food.


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Description Work on controlling the structuring process (acid gelation) of acid-sensitive hydrocolloids was initially set out to focus around alginate as the "model" hydrocolloid. The specific hydrocolloid proved rather problematic to work with, as the rate of gelation was too fast and uncontrollable, thus when added to a low pH solution an extensive gel was not formed. A decision was made to move to low acyl (LA) gellan gum as an alternative acid-sensitive hydrocolloid. Work on gellan proved highly successful and all the targets, envisaged for the alginate system, have been fully met.

The gel properties have been investigated and mixed gels have been studied. The mixed gel gives routes for both controlling the gelation rate and modifying the final mechanical properties of the gels produced. This is an important consideration as it allows the breakdown of the gel, with mechanical action (similar to that of the human stomach), to be controlled and manipulated to potentially give the optimal effect on further food consumption.

As the use of gellan for acid gelation was previously unknown and the control of gelation for mixed hyrocolloids has never been published, a patent was filed. Additionally, we have shown that this works in alcohol/water mixtures and thus a second patent was filled.

We have shown that fluid gels of acid set gellan gum gels can be produced. The microstructure obtained with a low concentration of gellan gum does not depend on the processing conditions. Texture analysis and rheology showed that at low gellan concentrations, manipulating the processing conditions during production has minimal impact on the material properties of the fluid gels. Calorimetric analysis showed that gelation and melting is unaffected by the fluid gel production. This shows that acid sensitive gellan gels can potentially be incorporated into foods including liquid like foods that can then be triggered in the stomach to give structuring.

One of the major aspects of employing acid-gels for structuring in the human stomach and promoting satiety would be to control energy release from these structures during the 'de-structuring' period. Starch (Maltodextrin) was incorporated into the gellan gel matrix as a source of energy. The results showed that Maltodextrin does not affect the gels' strength and that the Maltodextrin molecules diffuse out the gel matrix by a syneresis mechanism due to the external load. Hence, energy release as a function of time in the human stomach can be controlled and manipulated by the gel strength og the gellan gel or the mixed gellan/hydrocolloid gel.
Exploitation Route There are ongoing discussions with companies for licensing the IP developed from the project. The next stage is to move to testing the effect in humans and we are actively looking for a company to take this forward.

This work can potentially be used in convenient foods and drinks to give structures in the stomach that modify the feeling of hunger and reduce/slow down calorie consumption thus impacting on obesity.

New areas of research have been opened up and grant applications will be submitted.
Sectors Agriculture, Food and Drink

Description The effects found in the project have been used to show impact on human digestion. This has resulted in ongoing discussions with a large multinational company. The findings have been used to file 2 patents. The work has been published in a number of journal articles and review papers/book chapters and has been presented at a number of international conferences. The work was disseminated via DHRINC meetings to the UK food industry.
First Year Of Impact 2011
Sector Agriculture, Food and Drink
Impact Types Societal,Economic

Description Collaboration Prof Yeomans 
Organisation University of Sussex
Country United Kingdom 
Sector Academic/University 
PI Contribution A number of new collaborations have resulted from the DRINC club. These now both have a PhD studentship funded by industry. In addition, academic contacts and small scale collaborations have started with a Professor at the Institute of Nanosciences (Paris) There is potentially two new industrial collaboration (1) with Kraft and (2) with Diageo
Start Year 2010
Description Collaboration with Prof Halford UoLiverpool 
Organisation University of Liverpool
Country United Kingdom 
Sector Academic/University 
PI Contribution A number of new collaborations have resulted from the DRINC club. These now both have a PhD studentship funded by industry. In addition, academic contacts and small scale collaborations have started with a Professor at the Institute of Nanosciences (Paris) There is potentially two new industrial collaboration (1) with Kraft and (2) with Diageo
Start Year 2012
Description Collaboration with Prof Tristan Baumberger (Paris) 
Organisation Paris Diderot University
Country France 
Sector Academic/University 
PI Contribution A number of new collaborations have resulted from the DRINC club. These now both have a PhD studentship funded by industry. In addition, academic contacts and small scale collaborations have started with a Professor at the Institute of Nanosciences (Paris) There is potentially two new industrial collaboration (1) with Kraft and (2) with Diageo
Start Year 2012
Description The application relates to comestible products comprising acid gellable hydrocolloids, such as low acyl gellan gum. These are used for appetite suppression. On ingesting the product the hydrocolloid gels in the stomach. Mixed hydrocolloids, such as pectin and gellan gums are also provided. 
IP Reference WO2011131976 
Protection Patent application published
Year Protection Granted 2011
Licensed No
Impact None
Description The invention provides alcoholic comestible products comprising acid gellable hydrocolloids, such as gellan gum. Methods of suppressing alcohol consumption by consuming the product are also provided. 
IP Reference WO2012123748 
Protection Patent application published
Year Protection Granted 2012
Licensed No
Impact None
Description Dissemination 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact We have publicised the work through the University press office, appearing on BBC TV and in a number of national news papers. This has resulted in international coverage in for instance the USA and South America as well as main land Europe.

no actual impacts realised to date
Year(s) Of Engagement Activity 2009