A pectic polysaccharide in seed gum of Lepidium campestre
Lepidium campestre (field cress) is an oilseed species with a great potential of becoming a new commercial crop in Sweden. As the oil is being extracted from the crop, the residual from the extraction is left in form of a seed cake. As this seed cake is soaked in water a gel is formed around the...
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| Formato: | H2 |
| Lenguaje: | Inglés sueco |
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SLU/Department of Molecular Sciences
2017
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| Materias: |
| Sumario: | Lepidium campestre (field cress) is an oilseed species with a great potential of becoming
a new commercial crop in Sweden. As the oil is being extracted from the
crop, the residual from the extraction is left in form of a seed cake. As this seed cake
is soaked in water a gel is formed around the seeds. The purpose of this paper was to
study the chemical composition of the seed gum extracted from L. campestre and to
examine if a possible field of use exist for this substance. The seed gums function is
tested, but no real rheological study is executed and no study is done on the seed
itself. In this study, there is only one kind of seeds from one harvest analysed and
different kinds of varieties within the species L. campestre are not studied.
The seed gum was separated from the seeds and freeze-dried before analysed. The
determined molecular weight was 50-100 kDa, measured with Multi-Angel Light
Scattering. The measured absorbance in light absorbance spectrum resulted in a detected
substance at a wavelength of 280 nm, indicating aromatic amino acids in protein.
This however was in a very small concentration. Determination of soluble dietary
fibre was preformed according to The Uppsala Method, determination of neutral
sugar residues by gas chromatography and for uronic acid by spectrophotometry. To
further understand the structure of the seed gum, 1H NMR spectroscopy was performed.
The seed gum was consisting of up to 80 % dietary fibre and with a total
yield of 7 % from weight seeds. The results showed that the seed gum consist of a
high proportion of uronic acid, galactose and rhamnose - a rhamnogalactouronic pectic
substance. The pectin contributes to a very stable and reliable seed gum that could
be widely used in the food industry. Possible fields of applications are e. g. as dietary
fibre-enrichment in food products or production of gluten-free bread which is tested
in this study.
In this thesis, it is proven that it is a very easily extractable and easily isolated
substance that does not have any smell and most likely no taste. From L. campestre,
it is possible to get a substance made of a up to 80 % pure pectic substance, and all
that is required is water and a mixer. |
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