Havreprotein : Hur påverkas den vattenhållande förmågan och lösligheten av avfettning med etanol?

Sammanfattning: Oat products have become more and more popular in today´s society, as oats have healthy properties and can be classified as gluten-free. Oats also contain good fiber in the form of beta-glucans which are a soluble type of fiber that can lower cholesterol levels in the blood. It has also become more popular to use oats in various products as an ingredient and in these cases purified oat protein may be an option. Oat protein extract can be obtained by alkaline extraction at pH 9 and precipitation of the proteins at pH 5. This protein extract then needs to de defatted to obtain a pure protein extrakt. One problem with oat protein is that the solubility is generally low, which makes it difficult to use the protein extract as an ingredient in food.  This report examined how the water holding capacity and the solubility of oat protein were affected by defatting by ethanol. The defatting was performed either on the oatmeal before the protein extraction or on the protein extract after the extraction. These two methods are called fat+alki and alki+fat respectively. After the defatting there was no fat left in the protein extracts and the protein content was about 90 %. The water holding capacity of defatted protein extract treated with the fat+alki method was 1,98 g/g and for alki+fat the value was 1,74 g/g, these values can be compared with the water holding capacity of the protein extract which was 0,88 g/g. Experiments done on the solubility of defatted protein extract confirmed that the solubility at pH 5 was lower than at pH 7,25 for the defatted protein, but no clear difference could be seen between the two different methods of defatting.  The conclusion that can be drawn from this study is that ethanol can be used to defat oat protein and that there will be no major difference in results for the fat content or protein content if the defatting is performed before or after the protein extraction. However, several of the experiments in the study need to be repeated to obtain more reliable results. There is also a need for more studies looking at alternative ways, which preferably do not use solvents, as solvents can pose a danger to the consumer.