Determination of macronutrient compositions in selected, frequently consumed cereals, cereal based foods, legumes and pulses prepared according to common culinary methods in Sri Lanka.

Cereal grains, legumes and pulses comprise the largest proportion in a typical South-Asian diet plate. This research is mainly focusing on determining the macronutrient composition of major cereals, legumes and pulses commonly consumed in local Sri Lankan cuisine, in their cooked form. White samba, White Basmati, Red Kekulu and Nadu rice were selected as the main rice varieties and in addition maize, and wheat, finger millet flour-based foods too were analyzed. Red cowpea, green gram, chickpea and soya bean based foods were analyzed for macronutrient compositions as they are more frequently consumed by the local population, while the most preferred curry item; 'lentils', was analyzed along with soya curry; another preferred item by millions of locals. Wheat flour based items like bread were taken into analysis since, they have become the second most preferred food next to rice. Every item was cooked according to the common culinary practices in aim to determine the "realistic nutrient gain". Proximate analysis was carried out according to the AOAC standard guidelines for the determination of moisture, carbohydrate, fat, and protein whereas, insoluble dietary fiber and soluble dietary fiber were determined using enzymatic digestion in vitro models. Results revealed digestible carbohydrate level range from 64.6 ± 5.3 to 74.6 ± 7.2% among tested rice varieties, while protein content varies from 5.6 ± 2.2 to 8.9 ± 2.6. Insoluble dietary fiber was high in boiled raw rice (9.8 ± 0.2) and low in boiled White Basmati. Amongst tested leguminous beans, pressure cooked red cowpea elicited the highest protein level (24.5 ± 2.3%), while pressure cooked green gram had the lowest protein content (20.0 ± 0.6%). Pressure cooked chick pea was having higher insoluble dietary content (14.8 ± 1.3%) compared to other beans. Soybean curry elicited the highest protein (36.6%) and fat content (8.2%) among all the tested varieties. Pittu (puttu) and roti varieties made with wheat flour and finger millet flour resulted considerably higher levels of digestible fiber compared to roti made with whole wheat flour. It can be concluded that typical Sri Lankan diets are rich in fibre and protein, while they provide excellent macronutrient profiles due to the proper complementary mixing of food ingredients.

Effect of different milling methods on glycaemic response of foods made with finger millet (Eucenea coracana) flour.

OBJECTIVES: Compare glycaemic response of foods prepared with finger millet flour, using traditional stone grinding and industrial milling. DESIGN: Crossover study. PARTICIPANTS: Healthy volunteers (n=11) consisting of five males and six females), aged between 20 and 30 years, with a body mass index of 18.5-23.5 Kgm-2. MAIN OUTCOME MEASURES: Blood glucose concentration was measured at fasting and 30, 45, 60, 90, 120 minutes after ingestion of roti and pittu made with stone ground or industrially milled finger millet flour, containing 50 g of available carbohydrates. Glycaemic Index (GI) values were expressed as the average value of the 11 subjects. RESULTS: Significant differences (p<0.05) in GI between similar food types made of flour milled using different methods were observed. GI for roti made of stone ground flour was 44±5 and that of roti made of industrially milled flour was 59±7. Pittu made of stone ground flour had a GI of 67±5 and GI of pittu made of industrially milled flour was 79±5. Microscopic analysis of flour samples and a sieving process using different sieve sizes showed larger particle size distribution in stone ground flour compared to industrially milled flour. CONCLUSIONS: Larger particle sizes in the stone ground flour compared with industrially milled flour was established as the only factor affecting the difference in GI of same type of food prepared with flour milled using different methods. There were no significant differences (p>0.05) in proximate compositions of the different foods or raw flours. Foods prepared with finger millet (kurakkan) flour with a larger particle size distribution resulted in a lower glycaemic response.

Artefact reduction in dual-radionuclide subtraction studies.

A method is proposed which significantly reduces the artefacts commonly experienced in dual radionuclide subtraction studies. Images of two radionuclides recorded simultaneously differ in resolution, sensitivity and attenuation. Also, one image will include scatter from the second higher-energy radionuclide. As a result severe artefacts are likely to occur when the two images are subtracted. In order to minimise the depth dependence of resolution, attenuation and scatter, the geometric mean of conjugate views was considered. From experimental work with activity placed in a depth of water it was demonstrated that the number and spatial distribution of scattered photons recorded in any energy window could be accurately predicted from the geometric mean image recorded in the photopeak. This prediction was accurate, independent of the depth of the source in water for a range of phantom dimensions. Differences in the instrument sensitivity and resolution at different energies can also be readily compensated for by using geometric mean images, as can differences due to the variation in attenuation. In practice three factors can be experimentally determined for any pair of radionuclides: a scatter ratio, a scatter function and a resolution compensation function. These data are then used to improve the dual-radionuclide subtraction analysis. The ability of the technique to significantly reduce subtraction artefacts has been demonstrated in phantom studies.