Production of stable fat-reduced emulsions with improved quality

Research project ”Structurisation of food emulsions”

Responding to the consumer trend towards fat-reduced food is quite a challenge for the food industry. Within the scope of an FEI-sponsored project, it was shown that emulsifier system and dispersion process cannot be considered separately if oil-in-water emulsions shall be optimally adjusted and produced. The results from this project can be applied by the industry immediately and to many different products. This way, quality, stability and safety of food products can be optimized.

Total delicatessen sales in Germany accounted for about € 1.18m in 2007. About 50% of the products were o/w emulsions such as mayonnaise, salad dressings, sauces, cream soups and bread spreads. Their rheological and sensory properties are - depending on the current fat content - defined either by the disperse fat phase or the continuous water phase.

The consumers increasingly demand fat-reduced food products. Up to now, the production of fat-reduced emulsions is connected with significant quality deviations. Many fat-reduced products were not successful on the market or already failed during the development stage because the desired quality could not be achieved.

Problems are e.g. that too high amounts of stabilizer result in undesirable firm, visco-elastic textures. The inhomogeneous distribution of the fat particles and fat particle clusters formed by phase separation may yield undesirable sensory and rheological properties.

The larger amount of water present in fat-reduced products because of the lower fat content must be modified in a way as to achieve the sensory properties as well as the product safety and stability of comparable fat-containing standard products.

Objective of the present research project was the structuring of fat-reduced emulsions. Their physical and sensory properties should be improved by a permanent homogeneous distribution of the disperse fat phase in the continuous water phase. This can be achieved by using energetic interactions between the phases as well as by producing a large specific surface of the fat phase with narrow particle size distribution.

Using salad dressings and bread spreads as sample products, it was shown within the course of the project that emulsifier system and dispersion process have to be considered in close context in order to obtain an optimal final product. Despite the general correlations, a specific fine tuning is still required for each individual application. Although the two-stage high pressure homogenization in general proved to be the best method to achieve a large surface of the disperse phase with a narrow distribution, the stabilizer to be used has to be chosen according to the pH range of the emulsion. For detailed results please refer to the enclosed abstract.

The picture shows details of the CLMS images of emulsions. The left part of the picture shows the irregular spatial distribution of fat particles (red) in a commercial sample. The right part shows the test sample with a much more uniform fat distribution. This increases the stability and improves the texture.

The results from this project may be used in new product development and also provide a significant contribution to quality assurance. The food industry can apply the results to numerous products. Because only commercially available substances and processes have been used, the small and medium-sized enterprises that are predominantly active in the production of delicatessen products can immediately make use of the results.

This project was supported within the scope of the “program for promoting joint industrial research (IGF)” by the Federal Ministry for Economy and Technology (via AiF) through the Research Association of the Food Industry (FEI) (AiF project no 15218 N).

Next to DIL as research institution, the Federal Association of Producers of Food for Special Dietary Purposes (Diätverband), Bonn, also participated in the project as commercial partner.

Contact partner at DIL is:

Dr.-Ing. habil. Ute Bindrich
Phone: +49 (0)54 31.183 – 130
Fax: +49 (0)54 31.183 – 114
E-Mail: u.bindrich@dil-ev.de

For further information, please refer to the Project Abstract.

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