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

Yam (Discorea spp.) is an essential tuber crop for the hundreds of millions of people in many African, Asian and South American countries; considering in particular Southwest Nigeria, chips, flakes and flours are between 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 (p>0.05) in the moisture, crude protein and fibre content of all samples. Gross energy was also comparable for all yam derived food items, contradicting the common belief that yam flakes have lower nutritional value. As for 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 (p<0.05) existed between samples and various markets of source. Principal component analysis (PCA) showed a direct correlation between the ash content of the samples and the macronutrients assessed, irrespective of the market or seller of the commodities. This study confirmed that yam derived food stuff have an adequate nutritional composition, irrespective of their form and/or origin