Ultrasound pre-treatment of wheat bran to improve arabinoxylan extraction

Sammanfattning: With increasing amounts of food waste and diet related diseases, the need to utilize our by-products of food for its health benefits and to limit the food waste has never been more prevalent. Wheat bran is a by-product from the wheat flour industry and contains a lot of dietary fibres which has a beneficial effect on human health. One of these dietary fibres is arabinoxylan (AX). The aim of this thesis is to evaluate the effect ultrasonic pre-treatment has on arabinoxylan alkaline extraction from wheat bran. In parallel also evaluate the alkaline extraction process. Ultrasound can be applied in multiple ways with different power inputs, frequencies, and time durations. In this thesis, the studied parameter was time with 0.5-, 1-, 5-, and 10-minute-long treatments at 400 W power input. With the hypothesis that a longer treatment will give higher yields. The extraction process, including the destarching, delignification and the alkaline extraction of the wheat bran, worked successfully. The destarching removed high amounts of starch while the delignification could have been more efficient. The alkaline extraction isolated both water extractable AX and water unextractable AX, which was determined by the high arabinose to xylose (A/X) ratio. Ultrasound showed potential to increase the total solid yield and total carbohydrate content, but was not statistically significant. Ultrasound did not seem to affect the monosaccharide composition or the A/X ratio to any greater extent.