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

Abstract

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.

Keywords: Cereals; Cooking methods; Digestible carbohydrates; Macronutrients; Pulses.