Analysis of micronutrients variations among sweet potato (Ipomoea batatas [L.] Lam) genotypes in Malawi

Abstract

Sweet potato (Ipomoea batatas [L.] Lam) is an important root crop in Malawi and Sub-Saharan Africawhere micronutrient deficiency is an eminent health problem. Using 15 sweet potato genotypes grown in a randomized complete block design at Bvumbwe Research Station, a study was undertaken to determine the extent of variability of selected micronutrients in the genotypes as influenced by storage root age and peeling. Analysis of variance (ANOVA) showed significant (p≤ 0.01) variability among genotypes for dry mater, β-carotene, ascorbic acid levels and reduction of β-carotene due to peeling across all ages. Significant (p ≤ 0.05) variations in zinc, iron and copper were also observed among all genotypes. Peeling reduced β-carotene, ascorbic acid levels, iron, zinc and copper content while late harvesting resulted in low iron, zinc and copper. Therefore, 5 months after planting (MAP) and 4 MAP are recommended for high levels of β-carotene and ascorbic acid and iron, zinc and copper, respectively. Ten genotypes exhibited acceptable levels of dry mater of ≥30%. Zondeni (10.9 mg/100 g, WW) and Babache (23.84 mg/100 g, WW) had highest levels of β-carotene and ascorbic acid, respectively. Mzungu displayed the highest levels of Iron (0.67 mg/100 g, DW) and zinc (0.63 mg/100 g, DW) while Yoyera (0.61 mg/100 g, DW) had the highest levels of copper. Variations of various traits entail potential to breed for higher levels of micronutrients.Key words: Sweet potato, genotypes, β-carotene, ascorbic acid, iron, zinc, copper, peeling, storage root age. INTRODUCTIONApproximately one billion (795 million) people from developing countries suffer from hunger, malnutrition and poverty (FAO, 2015). Various reasons including climate change, environmental degradation, dwindling of natural resources and an ever increasing population have been implicated. In 2015, global population was estimated at 7.3 billion and was expected to climb up to about 9.7 billion in 2050 when nearly 90% of the population will be in resource poor developing countries of Asia, Africa and Latin America (James, 2015). The UN population projection shows that the trend will continue until the end of this century when the global population will reach 10.8 billion or more (UN DESA, 2015). Such increases in global population will result in ever increasing number of food in-secure people, who by definition are people with no physical and economic access to enough safe and nutritious food which meets their dietary needs at all times (FAO, 1996). However, over 3 billion people suffer from a different, sneakier form of hunger than the simple lack of sufficient quantities of foodstuffs referred to as micronutrient malnutrition or "hidden hunger" which is caused by a lack of food of sufficient dietary quality (Kennedy et al., 2003; FAO, 2013). Monotonous diets which are a hallmark of Sub-Saharan countries, based on cereals and other starchy staple foods frequently fail to deliver sufficient quantities of essential minerals and vitamins like Iodine, Iron, Zinc and Vitamin A (D...

Effect of predrying treatment and drying temperature on proximate composition, mineral contents, and thermophysical properties of anchote (Coccinia abyssinica (Lam.) Cogn.) flour

“…Copper is used for the synthesis of hemoglobin, proper iron metabolism, and maintenance of blood vessels (Navarre, 2009). Table 2 shows the effect of predrying treatment and drying temperature this study shows that Cu content of anchote is higher than potato (0.623 -0.658 mg/100 g) and sweet potato (0.30 -0.49 mg/100 g) (Baranowska, Zarzecka, Gugała, & Mystkowska, 2017;Chipungu et al, 2017). However, a relatively higher Cu content was reported in a wild tuber, Raphionacme Splendens, found in Sudan (3.6 mg/100 g) (Doka, El Tigani, & Yagi, 2016).…”

Enhancement of nutritional quality and shelf life of fish products (powder & chapatti) via fortifying with orange‐fleshed sweet potato

“…Finally, the ethereal extract (petroleum ether phase) was collected and filled with petroleum ether in a 50 mL volumetric flask. The absorbance of the ethereal beta‐carotene extract was read at 450 nm in a UV/VIS spectrophotometer (SPCORD PLUS 50 model, made in Germany) (Chipungu et al., 2017). The ß‐carotene concentration (C in mg/L) was calculated using Lambert–Beer law from measured data of the absorbance as indicated in the following equation according to (Mamo et al., 2014)where, ε is the Molar extinction coefficient for β‐carotene in petroleum ether (138,900 L.mol.‐1.cm‐1), M is the molecular weight of β‐carotene (536.88 g.mol‐1) and L is the path length (generally equal to 1 cm), and V is the volume of extract.…”

Molecular genotyping of sweet potato (Ipomoea batatas L. Lam) accessions using microsatellites

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