Effect of Cooking Temperature on Mineral Content and Anti-nutritional Factors of Yam and Taro Grown in Southern Ethiopia

Abstract

This study aimed to determine the mineral composition and anti-nutritional factors, oxalate and phytate, of yam and taro grown in southern Ethiopia. In addition, the effect of cooking at different temperatures on the mineral compositions and anti-nutritional factors together with respective molar ratios Ca:oxalate, Zn:phytate, Ca:phytate and (Ca  phytate):Zn was determined. The mineral compositions were found to be: 21.8-15.7, 0.65-0.95, Co; and 0.18-0.68 Ni in mg/100 g of raw taro samples. Mineral content decreased by cooking except Fe and Ca in one variety of taro where they show a bit increment. The antinutritional factor to mineral ratio tends to imply that the relative bioavailability of the minerals after cooking was found to be increased except for that of Fe. These tubers may present health hazard potential, which in turn demands proper processing before consumption to eliminate the toxic effects of anti-nutritional factors.

Effect of cooking time on selected metals, oxalate and phytate contents of the raw and cooked lettuce from five farms in Ethiopia

“…Plant-based diets are often associated with micronutrient deficits, exacerbated in part by poor micronutrient bioavailability. The diet-related factors have a greater influence on the bioavailability of the micronutrients Chemistry International 4(1) (2018) [15][16][17][18][19][20][21][22][23] Effect of cooking time on selected metals, oxalate and phytate contents of the raw and cooked lettuce from five farms in Ethiopia in plant foods, particularly Ca, Fe and Zn, than on the macronutrients (Mohite et al 2013;Ayele et al, 2015). Phytate has been recognized as an anti-nutrient due to its adverse effects.…”

“…Furthermore, it is desirable to establish optimum time and temperature to process food in order to derive maximum health benefits. Ayele et al (2015) have reported the effect of cooking temperature on mineral content and antinutritional factors of yam and taro grown in southern Ethiopia. The study showed significant decrease in the phytate and oxalate contents of yam and taro on cooking and increase in the bioavailability of minerals in the cooked samples.…”

“…Recently some studies have been carried out on the mineral contents of plant-based food: kocho and bulla (Atlabachew and Chandravanshi, 2008), enset (Debebe et al, 2012), vegetables (Weldegebriel et al, 2012), cactus pear (Aregahegn et al, 2013a), yam (Aregahegn et al, 2013b), white lupin (Akalu and Chandravanshi 2014), linseed (Mekebo and Chandravanshi 2014) and ginger (Wagesho and Chandravanshi 2015) used in Ethiopia but not on the antinutritional factors and bioavailability of minerals except on yam and taro (Ayele et al, 2015).…”

Assessment of metals in roasted indigenous coffee varieties of Ethiopia

“…The amount of elements in plants, generally, depend on many factors; species, age, root distribution of the plant, physical and chemical nature of the soil, proportions and distributions of elements and the general climatic conditions [20][21][22][23][24]. Under most conditions, metallic elements that enter animals are those contained in plants eaten or used as a beverage either directly or indirectly [19,25,26]. Thus, the metal content of edible plants frequently controls the amount of these elements available in different animal bodies.…”

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“…The results showed that almost all mineral element concentrations in peel were higher than those in tissue. A lot of investigations on elemental content of yam were carried out in Nigeria (Okwu and Ndu, 2006;Ayele, 2009;Ameh, 2007;Karim et al, 2013;Olajumoke et al, 2014). Other studies were conducted mainly in India (Shanthakumari et al, 2008), South Korea (Shin et al, 2012), Ghana (Dufie et al, 2013;Polycarp et al, 2012), Cote d'Ivoire (Kouadio et al, 2013), etc., where AAS and ICP-AES have been widely used to determine mineral elemental content.…”