Influence of harvesting time on the phenolic composition, antioxidant activities and anti-cholinesterase potential of processed yellow yam (Dioscorea cayenensis)

The present study seeks to evaluate the influence of the time of harvest on the phenolic composition, antioxidant activities and anti-cholinesterase action of processed yellow yam (Dioscorea cayenensis). HPLC-DAD analysis of the processed yellow yam revealed the presence of some phenolic acids and flavonoids. The result showed a higher amount of most of the identified phenolic compounds in the early harvested yellow yam. The result also showed a high level of most phenolic compounds in the raw yellow yam for both early and late harvested yam sample compared to their cooked counterpart. Similarly, the result of the antioxidant indices (total phenolic content, total flavonoid content, reducing power, ABTS and DPPH radical scavenging power) also ranked high in the early harvested and raw yellow yam sample compared to the late harvested and cooked yellow yam sample respectively. However, the anticholinesterase inhibitory action of the studied yellow yam revealed some level of inhibition only in the late harvested yellow yam with a slightly higher inhibition in the late harvested raw yellow yam compared to the cooked counterpart. Therefore the studied yellow yam when subjected to mild cooking process and harvested not very late could serve well as a functional food that could be harnessed in the management of free radical mediate