Objectives
- To extract mucilage from flaxseed.
- To determine the composition of the extracted flax mucilage.
- To determine the effect of mucilage on the sensory acceptance of high carbohydrate
- snack foods.
- To determine the effects of mucilage, as a product ingredient, on glycemic response
- to carbohydrate foods in individuals with both normal blood glucose response.
Project Description
Dietary fibre enhances a number of physiological functions, particularly gastrointestinal functioning. The consumption of non-fermentable dietary fibre, also called insoluble dietary fibre, has long been established in the prevention and treatment of constipation through fecal bulking and decreased transit time. It was once thought that the laxative effect of 11011-fennentable fibre was diminished with decreasing particle size. However, a recent investigation has shown that particle reduction has no significant effect on laxation. The presence of viscous, soluble dietary fibre in foods is known to alter the glycemic response of carbohydrate-containing foods, as this fibre delays gastric emptying and absorption of glucose. The luminal viscosity enhancing characteristics of viscous fibre can reduce bile acid reabsorption and improve cholesterol profiles. Viscous fibres are fermented in the colon, resulting in moderate fecal bulking and the production of short chain fatty acids, i.e. butyrate, propionate and acetate. Butyrate, the preferred substrate of the colonic mucosa cell is thought to be preventative in colonic cancer. The current North American recommendation for total fibre for adults is 14 g per 1000 kcal, approximately 21-25 g per day for adult women and 30-38 g for adult men. As current intakes of the general population are much lower than this recommendation, novel fibre sources may need to be incorporated into the diet to reach recommended intake levels.
Since the inception of the Glycemic Index approximately two decades ago, much research has been dedicated to the various types of soluble dietary fibre and their effects on blood glucose response. Oat fibres, such as bran, gum, and beta-glucan, have been
shown to delay glucose absorption from the upper small intestine and lower blood
glucose levels in healthy and diabetic subjects. Pectin, a soluble fibre found in fruit, has been shown to lower glycemic response by slowing the digestion of carbohydrate and, therefore, limiting the availability of sugar for mucosal absorption.
Arabinoxylan fibre, a soluble fibre extracted from the byproduct of processed wheat
flour, has been shown to decrease post-prandial glucose levels and insulin responses in
healthy individuals. Although the effects of many soluble fibres on glycemic response have been demonstrated, little data is available on the glycemic effects of soluble flax fibre.
Flaxseed has been consumed for many years, and now flax ingredients are becoming increasingly common. Little is known about the functional and clinical effects of soluble flax fibre, i.e. mucilage. Wann water extraction of mucilage from whole flaxseed has been investigated, but little work has been done on the clinical applications of this fibre fraction.
Flax mucilage was successfully incorporated into low moisture snack foods. Puffed wheat cake and rice crisp cake containing mucilage was not distinguishable from the control snack foods, and acceptability of all products remained high. The addition of
2 g of mucilage to 50 g of available carbohydrate resulted in significant reductions in glycemic response in healthy subjects.
