Functional Foods for Healthier Diets
Nisha Aravind is studying the addition of various healthy ingredients such as inulin to reduce the glycaemic index of pasta at Tamworth Agricultural Institute. Her research is supported by a Primary Industries Innovation Centre (PIIC) PhD Scholarship and her supervisors are Dr Mike Sissons (NSW DPI) and Dr Chris Fellows (UNE).
There is growing awareness of the beneficial effects of a healthy diet on the quality of life and many initiatives have been taken by scientists around the globe to develop food products with special health-enhancing qualities. Food additives dubbed “nutraceuticals” with desirable functional characteristics can be incorporated into basic foods without sacrificing taste, mouth-feel, or cooking properties.
Inulins are polysaccharides and belong to a class of carbohydrates known as fructans. They are produced by many types of plants but the most commonly used source for extraction of inulin on a commercial basis is from chicory (Cichorium intybus) roots. Inulin can be used to replace sugar, fat and flour but contains a third to a quarter of the food energy of sugar or other carbohydrates and a sixth to a ninth of the food energy of fat. After ingestion inulin is not broken down by the human digestive system. This makes it effective in decreasing the glycaemic index, a measure of the rise in blood sugar following the ingestion of foods containing carbohydrates. Inulin has the potential to reduce the glycaemic index of pasta without compromising product quality or consumer preference. Ingestion of inulin also results in a significant increase of beneficial bacteria in the colon at the expense of less beneficial bacteria. It has also been shown to reduce lipid levels.
Nisha is analysing the effect on the taste, quality, and beneficial properties of pasta after the addition of different levels of inulin to the semolina. She has subjected pasta enriched with 2.5,5, 7.5, 10 and 20 % inulin to both instrumental and sensory analysis to obtain quantitative and qualitative data and determined the effect of inulin addition on the cooking properties, texture and in vitro digestibility of durum wheat pasta. Increasing levels of inulin in the pasta caused a gradual decrease in swelling index, firmness and colour. Inulin did not affect the stickiness of the pasta or the acceptability for human consumption. Inclusion of up to 5% of inulin in the pasta reduced the rate of starch digestion. Above 5% inulin, starch digestion increased and at 20% inulin, the starch digestion was greater than the nil inulin control. Nisha hypothesises that up to 5% inulin encapsulates the starch granules in a protective coat. Above this level inulin results in a breakdown of the starch-protein continuum leading to increased enzymic activity and release of sugars.
Contact: Ms Nisha Aravind nisha.aravind@dpi.nsw.gov.au