Aim: To explore the nutrients, minerals, beta-carotene and total carotenoid contents of five sweet potato varieties viz., Agric orange flesh, Agric white, Red skin, Orange flesh and T.U. purple. Study Design: The sweet potato vines at six week stage were cut into 1.2m each and transplanted in parallel lines on the same 1.2m x 2.6m bed, spaced about 0.52m from each other in Dukumah Garden. There were five such beds and vine cuttings transplanted in the same order on each bed. Study Site: The study, which took four months, was conducted in the Dukumah Garden in Bolgatanga Municipality (10.7875° N, 0.8580° W) of the Upper East Region of Ghana. Methodology: The sweet potatoes were harvested four months after transplanting on the same day. Samples of the various varieties were collected, parcelled, appropriately labelled and handdelivered to the Food Chemistry Laboratory of Kwame Nkrumah University of Science and Technology for the analysis of proximate analysis (%), total carotenoids and beta-carotene concentrations in mg/g and concentrations of the minerals, namely magnesium (Mg), sodium (Na), potassium (K), calcium (Ca), iron (Fe) and zinc (Zn) in mg/kg. Results: All the five varieties of sweet potato were found to be nutritious. Protein content ranged from 3.82% in Agric white variety to 0.11% in Agric orange flesh. Fat content ranged from 4.84% in orange flesh variety to 1.74% in red skin. Crude fibre content was between 1.77% in Agric orange flesh and 0.10% in T.U. purple. Total carbohydrate varied from 23.2% in Agric orange flesh variety to 15.8% in Agric white one. Moisture was high in all the varieties, ranging from 75.78% in Agric white variety to 71.04% in Orange flesh one. The Orange flesh variety had the highest ash content of 1.56%. All the varieties contained high concentrations of Mg but low concentrations of Na and K. The highest concentration of Ca (8250.70±0.06 mg/kg) was recorded in T.U. purple. The concentrations of Fe in the sweet potato varieties decreased in the following order: T.U. purple>Red skin>Orange flesh>Agric orange flesh>Agric white. The highest (123.12±0.00 mg/kg) and the lowest (33.10±0.00 mg/kg) Zn concentration were recorded in the orange flesh Agric white varieties, respectively. The concentration of beta-carotene (mg/kg) in five sweet potato varieties was in the following order: Agric orange flesh<

This work characterized the most cultivated and consumed yam ( Dioscorea ) cultivars within the Ghanaian yam germpla sm based on their biochemical and cell wall constituents to assess their potential alternative food and industrial processing applications. Samples were analyzed for their biochemical composition - starch, amylose, amylopectin, total sugars, reducing sugar s and non- reducing sugars along the head, middle and tail regions of each tuber using standard analytical methods. Cell wall constituents - acid detergent fibre, neutral detergent fibre, acid detergent lignin, cellulose and hemicellulose of each tuber were also determined using standard analytical methods. The results showed no significant differences at p<0.05 in biochemical compositions along the length of the studied cultivars. D. cayenensis (Pure -yellow), D. rotundata (Pona) and D. alata (Matches) were found to have high starch contents (63.16- 65.69%, 63.54- 65.30% and 63.24- 65.17% respectively). Amylose content was observed to vary along the length of the tubers for the varieties studied. D. alata (Matches) was observed to contain the highest amylose con tent of 19.66- 20.64%. No identifiable trend was however, observed for the amylopectin content along the length between the varieties investigated. D. bulbifera recorded the lowest amylopectin content of 41.29%, 43.59% and 44.63% while D. esculenta had the highest with 49.84%, 50.24% and 50.13% along the tail, middle and head sections respectively. Total sugar content varied significantly (p<0.05) along the lengths of all the varieties investigated. It was higher at the tail portions for all the varieties studied than the head regions; the middle portions recorded the least. D. bulbifera recorded highest total sugar contents (4.74- 4.84%) and total sucrose (3.58 -3.64%). There were significant differences ( p<0.05) in the cell wall constituents of the yam varieties. Cellulose was found to be the most common cell wall component with D. rotundata having the highest level of 3.36% whilst D. dumetorum had the least (1.56%). Hemicellulose content ranged between 0.42 g/100g in D. alata to 4.58 g/100g in D. esculenta while lignin content ranged from 1.56 g/100g in D. dumetorum to 2.87 g/100g for D. praehensalis . There were significant differences (p<0.05) in the neutral detergent fibre found in Dioscorea esculenta and the other yam species . It ranged from 1.18 g/100g in D. alata to 5.46 g/100g in D. esculenta . Less than 1% of acid detergent fibre was identified in the yam varieties , suggesting varied levels of biochemical composition and cell wall constituents in the different yam varieties .