Healthier food by biofortification – natural increase of folate content by bioprocessing
Thomas Andlid (project leader)
Summary of results with list of publications from Food Science, CTH.
Email: ta@fsc.chalmers.se
Good yeast makes good bread
Before and during the first weeks of pregnancy, Vitamin B, folate (folic acid) reduces the risk of neural tube defects such as spina bifida. A high intake has also been shown to help reduce the homocysteins level in the blood. Elevated levels are considered to be a risk factor for cardiovascular diseases and Alzheimer's disease. It is however difficult to ingest sufficient quantities of folate through the food, and new strategies to increase intake should therefore be developed. In many countries, obligatory enrichment of flour with synthetically produced folic acid has been introduced. The Swedish Food Administration has however decided not to introduce enrichment but instead to promote the consumption of food naturally rich in folate and to increase information directed at women of fertile years.
The aim of the project was to investigate whether and how yeast can be used to increase its natural folate content (through biofortification). In contrast to mammals which must satisfy all their folate needs via their food, yeast itself produces folate – a property that can be utilised to a greater degree. The folate content of different yeast strains was therefore determined and studies conducted of the impact of cultivation conditions on folate levels. The results may be useful for the production of foods with high contents of natural phosphate. From the biological standpoint, the results are also of interest since they can help increase our understanding of folate metabolism.
The use of resistant starch and HCG as model for the manipulation of skatole and androstenone metabolism
Kerstin Lundström (project leader)
Summary of results with list of publications from Food Science, SLU.
Email: Kerstin.Lundstrom@lmv.slu.se
Boar taint
Castration of pigs is generally carried out to eliminate boar taint in the meat. This odour is primarily caused by two substances (androstenone and skatole) which are produced by some male pigs during puberty. Entire male pigs have a better muscle composition which makes for more effective utilisation of protein, lower losses of nitrogen and a more sustainable production. Owing to the increasing interest in animal welfare aspects, increased resistance to castration may be expected, since the procedure is painful when performed without an anaesthetic. The EU intends to introduce a prohibition of castration as soon as this is feasible. However, in order that castration may be stopped without the risk of reduced consumption, the problem due to boar taint in carcasses must be reduced. Genetic selection is most effective, but without an understanding of the connection between skatole, androstenone and sex hormones, negative genetic effects may arise in the reproductive characteristics.
The objective of this project was to investigate the mechanisms that determine the final contents of the substances which give rise to boar taint. This was done by manipulating the levels of skatole, androstenone and sex hormones with resistant starch and HCG (human chorionic gonadotropin). Other mechanisms were also studied. The feed can reduce skatole content but not the androstenone content. This means that feed containing resistant starch can solve only part of the odour problem. When castration is discussed in an animal welfare context, the problems due to the increased aggressiveness and the sexual behaviour of entire male pigs in connection with puberty is often ignored.
It is not certain that animal care is improved if the relatively short lived pain in castration is replaced by several months of increased restlessness and aggressiveness. If pigs are not to be castrated in Sweden, other methods are needed to reduce the taint and to ensure good animal care.
Generalist predators – a study of predation, food choice and competition on organic and conventional farms
Barbara Ekbom (project leader)
Summary of results with list of publications from Ecology, SLU.
Email: Barbara.Ekbom@entom.slu.se
Some insects and spiders eat economically significant insect pests. These natural enemies should be conserved and promoted in the farming landscape. To be able to promote natural enemies which have the greatest ability to control insect pests requires detailed knowledge of their food intake. To see by the naked eye what an arthropod eats is however a challenging task since they are often small and live in dense vegetation. Some hunt only during the night. By analysing what these predators have in their guts, these problems can be overcome.
DNA residues of aphids in the guts of ground living spiders of the genus Pardosa have been detected since the aphid is an economically significant pest in spring-sown cereals. In order that natural enemies may be able to control these pests, they must find and eat the aphids early in the season.
However, spiders eat not only aphids but can balance their nutriment intake. Springtails are also an important alternative. These are common small decomposing insects in agricultural soil. Consumption by a predator of prey that is not an insect pest has both advantages and drawbacks. With good access to an alternative supply of food the predators will be in good condition, can increase in numbers and remain in the crop. But if the alternative food, e.g. springtails, is more attractive than the pest, high densities may result in reduction of predation on the aphids.
The project tested the theory that consumption of springtails can modify spiders' consumption of aphids. This can simplify studies of interactions between springtails and natural enemies and facilitate further research all over the world. Molecular methods provide new opportunities for studying the gut content of a predator and will in the long run improve biological pest control.
Fragmented grasslands in time and space: diversity at genetic, species and landscape level
Honor C Prentice (project leader)
Summary of results with list of publications from Ecology, Lund University.
Email: Honor_C.Prentice@ekol.lu.se
Semi-natural grasslands in traditionally managed landscapes are characterised by great species diversity. These grasslands have however suffered severe losses over the past decades owing to the rationalisation of agriculture.
In the project, a study was made of the significance of the spatial distribution and environmental conditions of these grasslands and the history of species diversity among vascular plants in the remaining grassland fragments. With the help of historic maps and aerial photographs, it was shown that semi-natural grasslands had continuously decreased in extent and been fragmented since the beginning of the 18th century. The total area of grassland in today's landscape in the study region makes up only 18% of the area of grassland 300 years ago. The results show that fragmentation has had a negative effect on species diversity and that continued losses of diversity may be expected in future.
The overall conclusion is that both management and spatial access to habitats are important factors for the diversity of vascular plants in today's semi-natural grasslands, which emphasises the importance of a landscape perspective in both time and space for the interpretation of species diversity today.
Biological control of grey mould in strawberries
Sandra Ann Ingela Wright (project leader)
Summary of results with list of publications from Cell and Molecular Biology, Göteborg University.
Email: sandra.wright@molbio.gu.se
Time for strawberries
Plant protection has for a long time been based on the use of fungicides which impede or kill different stages of the organisms (plant pathogens) that cause disease. Unfortunately, these chemicals also destroy the natural microflora of the plants. At the same time, consumers demand increasingly healthy foods and alternatives to chemical control agents in agriculture (e.g. fungi and bacteria). The objective of this project was therefore to isolate yeast epiphytes from strawberry blossoms, to test them, identify them and develop them for practical application as biological control agents against grey mould.
For a long time, chemical control has been the only means of controlling grey mould, but repeated treatment gave rise to new and more tolerant yeast isolates that resulted in far reaching negative effects on the environment and in health hazards for humans. Today, certain preparations cannot be used, and many more will be prohibited. The objective of the project was therefore to find new biological control mechanisms among yeast fungi and bacteria for the protection of strawberry plants against infection.