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

Anne started work in February on her GRDC funded post-graduate studies with PIIC. She will study the effects of soil amendments on cropping soils in the Central West of NSW. Anne’s supervisors are Assoc. Prof. Heiko Daniel, Dr Kathy King and Prof. Bob Martin.

Anne and husband Ray own a 1,420-hectare property “Magomadine”, 24 kilometres east of Coonamble, where they decided to go no-till farming after witnessing the damage done to soil by cultivation during the 1994 drought.

The focus of Anne’s studies is to understand why, after 12 years of no-till farming, soil biological tests are showing low levels of activity. Similar results have been reported in Queensland.

Anne intends to collect data on soil physical, chemical and biological activity on the soils of a range of farms in the Central West of NSW. Anne is a member of the Central West Conservation Farmers’ Association (CWCFA) and is encouraging members to be part of the study. The study will involve around 20 paired comparisons between farmed and natural systems. This will enable her to determine the changes that have occurred since clearing and which systems are the most resilient or beneficial to retaining healthy soil biological activity.

Anne will also establish a field experiment on “Magomadine” to determine if addition of soil amendments can improve the biological activity in the no-tillage system. One of the problems in a sub-tropical climate is that crop residues, composts and manures, the food for soil biota, disappear rapidly. So once the food is depleted we would expect biological activity to decline.

One possibility to enhance and prolong the biological activity is to convert some of the organic additions to biochar. Biochar is porous with large surface area and is thought to provide a place for soil microbes to live. Biochar is also an option for long-term sequestration of carbon. Other “enhancers” that Anne is considering include zeolite (to capture and reduce soil nutrient losses). Anne is also going to include a wild card, blue metal dust from the quarry on Magomadine. No one knows what blue metal dust actually does but why not give it a go?

Anne is a very focussed mature-age student. She is a UNE science graduate and taught school to supplement the farm income from 1990-2000. The increased income from the no-tillage venture eventually allowed Anne to give up teaching.

With all that spare time on her hands Anne went back to study and completed a Bachelor of Applied Science in Agriculture as well as a Graduate Diploma with Charles Sturt University. This motivated Anne to further her studies to understand more about the soil biological processes operating in the farming system.

“I’d like to look at the theory that we need to put good organisms including fungi, bacteria, protozoa, nematodes and micro-arthropods back into the soil because some farming practices damage them. By doing that we should be able to lower nitrate levels on which weeds depend and increase ammonium levels which benefit crop production.”

Anne’s husband Ray is an essential part of the team and often the one left to work out how put theory into practice. This guarantees a built-in reality check. We wish Anne (and Ray) all the best in this exciting new project.