ABSTRACT

The effects of processing on nutrient composition, phytochemicals and carotenoid profile of two cultivars of Pterocarpus santalinoides were investigated. The tender leaves of Pterocarpus santalinoides was selected, washed, surface air dried, sliced at 1.5 m, then divided into four portions, raw, oven dried (500C for 1h 20 min), sautéed (500g/20ml) of fat and Blanched (1000C) for 3 min. The proximate composition, vitamins, minerals, and phytochemicals were determined according to standard methods. Carotenoid profile was determined using HPLC. The moisture content ranged from 36.84 – 76.66 %, crude protein; 12.68 – 16.42 %; Oven drying and sautéing improved the crude protein content, Ash content ranged from 1.84 to 4.15 % and was improved by oven drying. Crude fibre was moderately present in the cultivars (1.95 – 3.72 %). Oven dried Afu had high crude fibre (3.72%) than other samples (p<0.05). The Pterocarpus santalinoides cultivars are good sources of energy (81.18 – 248 K/J. Vitamin B6 (41.07 – 94.17), Afu blanched had the highest quantity of vitamin B6 (94.17 mg/100g) Pro-vitamin A content ranged from 8.95 – 243.72 µg/g and  was in the highest amongst in sautéed Afu (243.72 µg/g). Vitamin C value ranged from 13.42 to 20.39 mg/100g. Raw Osw was higher in vitamin C (20.39 mg/100g), vitamin B1, B2, B3, B9 and vitamin E were in trace amount. Iodine content ranged from 45.99 to 63.33 mg/100g was significantly higher (p<0.05) in Raw Osw (63.33 mg/100g).  Processing moderately reduced the iodine content. Potassium content ranged from 40.00 to 59.50 mg/100g. Osw oven dried sample had the highest iodine content (59.50 mg/100g). Magnesium content ranged from 42.12 to 44.90 mg/100g. Oven drying and sautéing improved magnesium in Osw significantly (p<0.05) (44.90 %). Iron was present in appreciable amounts (6.20 – 7.75 mg/100g).  Processing did not have any significant effect on the iron content of the cultivars. Calcium (3.50 – 4.09 mg/100g) was moderately available; oven drying and sautéing significantly improved the iron content among others (4.08 and 4.09 %). Zinc (1.10 –1.29) was in trace amount. Phytochemicals analyzed were in trace amount except alkaloid (3.38 –7.73 mg/100g), oven dried and sautéed samples (4.62 and 4.52 %) respectively moderately reduced the alkaloid but blanching drastically reduced it (3.38%). The total β carotene ranged from 8.08 to 232 µg/g. Sautéing improved the total β carotene; sautéed Afu had the highest value (232.46%). Trans β carotene was present in measurable concentration (3.97 –108.15 µg/g), sautéed Afu and Osw (108.15, 102.75 µg/g) had the highest values. 13-cis β carotene was in appreciable concentration (2.58 – 86.31 µg/g). Sautéed Afu had the highest 13-cis β carotene content (86.31µg/g) significantly. - Carotene (1.66 – 23.83 µg/g) was in trace amount, but sautéing significantly improved it to 23.83, 22.53 µg/g. The chromatogram showed (4 – 7) major peaks and several minor peaks that were not identified due to lack of standard. Afu cultivar had more carotenoid than Osw cultivar. Sautéing was the best method for enhancing the carotenoid profile.