Study of the proximate and mineral composition of different Nigerian yam chips, flakes and flours

Abstract

Yam ( spp) is an essential tuber crop for hundreds of millions of people in many African, Asian and South American countries. Considering in particular Southwest Nigeria, chips, flakes and flours are amongst the most common shelf-stable traditionally-processed yam products. This paper reports a systematic study on the proximate (moisture, protein, carbohydrate, fibre, fat, ash and gross energy) and mineral composition of these three food commodities sold in Nigerian markets. Results showed no significant differences in the moisture, crude protein and fibre content of all samples (10.0-12.3, 2.7-4.3 and 1.3-2.0 wt%, respectively). Gross energy was also comparable for all yam derived food items (between 3300 and 3507 kcal/kg), contradicting the common belief that yam flakes have lower nutritional value than chips and flours. Considering the mineral composition, Ca, Mg, P and K were the predominant macronutrients. Micronutrients such as Zn, Co, Mn and Cu were also detected. Significant differences existed between products, and their various sources (markets). Principal component analysis showed a direct correlation between ash content of the samples and the assessed macronutrients, irrespective of the market, or the seller of the commodities. This study confirmed that yam derived food stuffs have an adequate nutritional composition, irrespective of their form and/or origin.

Floral Biology and Pollination Efficiency in Yam (Dioscorea spp.)

“…This zone accounts for~92% (67.1 million tons) of the annual global yam production [7]. Yam is an important source of dietary nutrients [8,9] with a low glycemic index, which gives better protection against diabetes and obesity [10,11]. Yam value chain is a direct income-generating activity for more than five million people in West Africa [12].…”

Safety of Yam-Derived (Dioscorea rotundata) Foodstuffs—Chips, Flakes and Flour: Effect of Processing and Post-Processing Conditions

“…To minimize losses, freshly harvested yams are processed into dry products to reduce the water activity as much as possible; as such, chips and flakes are often obtained [1,12]. As reported by Omohimi et al [13], dried yam chips are produced through peeling, slicing, blanching, steeping, and sun-drying. Yam flakes are obtained with the same process as yam chips, where the drying process is faster due to the smaller size of the flakes.…”

“…The nutritional value of yam chips, flakes, and flour has been recently assessed by Omohimi et al [13]. Aside from carbohydrates, yam-derived foodstuffs are also a good source of minerals, such as Ca, Mg, P, and K, and oligominerals, such as Zn, Co, Mn, and Cu.…”

“…Currently, yam chips, flakes, and flour are produced by small and medium scale processors (cottage and rural processors) that employ non-standardized methods [5,13,14]. This can lead to differences in the quality of the final products from processor to processor, and from location to location, with consequent safety concerns.…”

“…This can lead to differences in the quality of the final products from processor to processor, and from location to location, with consequent safety concerns. These aspects are particularly relevant for all the food items produced in developing countries, as often the production processes involve the use of old, traditional methods and with poor awareness of safety [13]. Different contaminants can be present in yam products, such as heavy metals and organic pollutants [5,8,16], as well as microorganisms in the form of bacterial strains, fungi, or mycotoxins [17,18].…”