Orange fleshed sweet potato a nutrition sensitive functional food for possible dietary approach to vitamin A deficiency and undernutrition

Orange Fleshed Sweet Potatoes (OFSPs) is an excellent nutrition sensitive function food. It contains dense amount of carotene and is also rich in proximate nutrients. A wide number of cultivars of OFSPs has been developed worldwide, particularly in sub-Saharan Africa and Asia. In Bangladesh, sixteen cultivars have been developed. Carotene content in the OFSPs surpasses all of the plant food carotene. OFSPs also contains good content of energy yielding nutrients. The Orange Fleshed Sweet Potatoes could, therefore, be a potential dietary approach to address the vitamin A deficiency for undernourished indigent people.

Assessing the Productivity, Quality and Profitability of Orange Fleshed Sweet Potatoes Grown in Riverbank of the Tista Floodplain Agro-Ecological Zone of Bangladesh

Orange fleshed sweet potatoes (OFSP) are desirable for high productivity and profitability and their distribution to improve the nutrition of river bank inhabitants of Gaibandha and Rangpur districts of Bangladesh. In this context, a field trial was conducted in two riverbank-based farmers’ fields such as Saghata, Gaibandha, and Pirganj, Rangpur, particularly in the Active Tista Floodplain Agro-ecological Zone of Bangladesh. Four OFSP varieties were evaluated, i.e., G1: BARI SP-8; G2: BARI SP-12; G3: BARI SP-14; G4: BARI SP-15, along with one local cultivar as a control (Red skin with white flesh). Significant variations among the sweet potato genotypes were noted for a number of tuberous roots plant−1, length of root diameter of roots, tuberous root weight plant−1, root yield (fresh), root yield (dry), beta-carotene yield, as well as energy output. Over the locations, BARI SP-12 produced about 73% higher root yield (32.00 t ha−1) and it was like the BARI SP-8 (31.07 t ha−1), which produced about 68% higher yield in comparison with local cultivar (18.51 t ha−1). Across the location, BARI SP-8 performed better in root yield (31.89 t ha−1) in Gaibandha, 69% superior to local cultivar, whereas BARI SP-12 performed better in Rangpur (33.66 t ha−1), which was 86% greater than the local sweet potato cultivar. Considering the root dry yield production, BARI SP-8 produced the highest in the Gaibandha location after that Rangpur location. Further, BARI SP-14 had wider adaptability and stability over the year and location depended on the AMMI model. The beta carotene yield (Vitamin-A precursor) ranged 336–2957 kg ha−1 among the OFSP varieties, whereas the highest (2957 kg ha−1) carotene was recorded in BARI SP-14, similar to BARI SP-15 (2952 kg ha−1) but was much lower in BARI SP-8 and BARI SP-12. Moreover, BARI SP-8 and BARI SP-12 were also economically profitable in terms of gross margin (3233 and 3364 US$ ha−1, respectively), net return (3039 and 3170 US$ ha−1, respectively) and BCR (3.21 and 3.31, respectively, vs. 1.91) due to higher returns with a similar production cost of the local cultivar. The results suggested that BARI SP-8 is economically profitable in the riverbank areas of Gaibandha, and BARI SP-12 is suitable for the riverbank areas of Rangpur.

Physico-chemical and Sensory Properties of Bread Prepared from Wheat and Orange-Fleshed Sweet Potato (Flour, Starch and Non-Starch Residue Flour) Blends

Bread was produced from wheat (Trititum spp) orange flesh sweet potato (Ipomoea batatas L.) flour, starch and non-starch residue blends. The orange-fleshed sweet potatoes were washed, peeled, sliced, dried and milled to flour. The starch and non-starch residue were also produced from the orange-fleshed sweet potatoes. Different proportions of wheat and flour, wheat and starch and wheat and non-starch residue of orange-fleshed sweet potato with increasing level of orange-fleshed sweet potato at 10, 20, 30 and 40% addition in wheat were prepared. Control samples were 100% wheat flour (A0), 100% orange-fleshed sweet potato flour (A1), 100% orange-fleshed sweet potato starch (B1) and 100% orange-fleshed sweet potato non-starch residue (C1). Breads from these different proportions were formulated. The proximate, mineral, vitamin, physical properties and sensory attributes of the bread samples and their composites were determined. The GENSTAT Statistical Software (version 17.0) was used for data analyses. The Proximate compositions of the bread ranges as follows; moisture 26.30-36.21%, protein 0.85-7.89%, fat 6.33-8.93%, fiber 0.82-4.92%, ash 0.56-2.11% and carbohydrates 41.26-64.84%. The physical properties of the breads ranged from 210.60-254.00 g, 0.05-2.40 mm, 317.60-440.60 cm3 and 1.25-2.10 for loaf weight, oven spring, loaf volume and specific volume respectively. Mineral and vitamin composition for breads samples ranged respectively thus for calcium 18.45-33.21 zinc 0.92-6.27, magnesium 0.28-19.33, phosphorus 31.00-319.60 and potassium 56.30-352.60, vitamin B1, 0.10-0.37, vitamin B2, 0.07-1.23, vitamin B6, 0.09-1.25, vitamin B12 0.04-1.13 mg/100 g, vitamin C 0.12-14.17 mg/100 g and vitamin A 0.00-8193 µg/100 g.The sensory evaluation results indicated that up to 20% substitution of wheat flour with orange-fleshed sweet potato flour, starch and non-starch residue flours was acceptable in bread formulation.

Impact of Processing on Retention of Beta Carotene of Sweet Potatoes

The study was carried out to evaluate the impact of processing on retention of beta-carotene of sweet potatoes. Eight cultivars of sweet potatoes were used in the study; among which four cultivars were of orange-fleshed varieties viz. ‘CIP 440012’, ‘CIP 440015’, ‘CIP 440267’ & ‘CIP 440021’, and four cultivars were of white fleshed varieties viz. Lamatar White, Balewa Red, Sangachowk Red and Barbote White. The proximate composition and micronutrient composition of eight cultivars of raw sweet potatoes were determined. The carotene content of sweet potato cultivars was also calculated. Finally, the retention of carotene content in sweet potato cultivates under various processing methods (viz. boiling for 30 minutes at 100°C, baking in a microwave oven at 200°C for 30 minutes and drying in a cabinet dryer for 12 hours at 60°C) was observed. The orange fleshed varieties (CIP cultivars) had the greater proximate composition than the white fleshed varieties (local cultivars). The micronutrient composition of orange fleshed sweet potatoes and white fleshed varieties were similar. But the carotene content of the orange fleshed varieties was greater; ranging from 14.43-22.11 mg/100gm. The white fleshed varieties had a low carotene concentration of 0.70-1.83 mg/100gm. The retention of carotene content was observed higher in the boiling process (79%-89%) followed by baking (56%-78%) and least in drying (44%-67%). Also, the orange fleshed varieties had a better retention capability than white fleshed varieties in all the processing methods. Thus, orange fleshed sweet potatoes had a better nutrient profile with higher retention capabilities.

Chemical and physico-chemical properties of orange fleshed sweet potatoes (OFSP) chips dried using solar dyers

In this study, drying technology was employed to process fresh orange fleshed sweet potatoes (OFSP) into dried slices using NSPRI improved solar tent dryer, parabolic shaped solar tent dryer in comparison with open air drying and its effect on the chemical, physico-chemical and mineral constituents of dried OFSP slices was investigated. Results showed that the dried-OFSP contained ash (3.69-4.09 %), fat (4.09-5.09 %), crude fibre (4.69-5.15 %), protein (5.87-8.28 %), carbohydrate (78.22-82.21 %), vitamin C (8.55-20.49 mg/100g), phenolics (0.1-1.28 mg/kg), flavonoids (984-145 mg/kg) and reducing sugar (35.01-82.23 g/100g). The total titratable acidity of the dried OFSP slices varied between 0.56-0.89 %, total soluble solids ranged between 5.70-7.00 °Brix while pH ranged between 4.94-6.47. Zinc, magnesium, potassium, calcium, sodium, iron were present in varying levels but aluminium, lead and cadmium were not detected in all the samples. This study therefore showed that good quality dried OFSP slices with appreciable nutrient content can be obtained from drying in NSPRI solar tent dryers especially with the use of the parabolic shaped solar tent dryer. Thus, the parabolic solar tent dryer is recommended for drying crops. Keywords: Drying technology, Orange fleshed sweet potato, NSPRI solar dyers, Physicochemical properties