Postharvest responses of tannia (Xanthosoma sagittifolium) leaves to mechanical wounding

Abstract

Tannia leaves are consumed in many regions of Tropical Americas and Africa. Due to large size and fragility, leaves are subjected to physical wounding during handling. As a result, visual symptoms of yellowing develop at wounding and adjacent tissues. The aim of this study was to evaluate the effect of mechanical injury on the physiological changes of tannia leaves at damaged tissue and adjacent areas. For this purpose, the lamina of leaves was perforated for several times with a needle. Then, the leaf samples were excised off as follows: a 0.6 cm diameter (circle A), containing the injured area; 1.1 cm O-ring B, around the circle A, 1.6 cm O-ring C, around the B. Control samples were taken from the opposite side of the leaves free of any wounding. Analysis of fresh weight loss and concentration of soluble phenolic compounds were performed after 30 min, 2, 4 and 6 h and the leaf chlorophyll content was determined after 30 min, 24, 48 and 72 h. The mechanical injury increased the postharvest accumulated fresh weight loss by 59.1% on circle A and by 22.6% on O-ring B after 6 h. The injured circle A accumulated 56% more soluble phenolic over the period of 6 h, which can be related to the activation of defense mechanism by the cell. The rate of chlorophyll degradation was not affected by the injury up to 72 h after wounding. Leaf wounding increases fresh weight loss and induces accumulation of soluble phenolic compounds at location of the injury.

Assessing the Productivity and Socioeconomic Feasibility of Cocoyam and Teak Agroforestry for Food Security

“…As well as being consumed as they are, cocoyam tubers can also be processed into flour [47][48][49] to be used as a base for making noodles/pasta [50][51][52][53], biscuits/cookies [54][55][56], meat analogs [57,58], yogurt mixes [59,60], food thickeners [61], bioplastics [62,63], and edible films [64]. The leaves and stems of this plant can also be used as animal feed, wound medicines [65], painkillers [66], diabetes medicines [39], antileukemia medicines [67], and biofuel [38,68,69]. It can be grown as a monoculture [70,71] or intercropped with other crops.…”