Browsing by Author "Upadhyaya, Mahesh K."

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Changes in water potential, osmotic potential, and tissue electrolyte leakage during mass loss in carrots stored under different conditions
(Elsevier Science B.V, 2002-08-02) Shibairo, Solomon I.; Upadhyaya, Mahesh K.; Toivonen, Peter M.A
Mass loss, water potential (ψ), osmotic potential (ψπ) and tissue permeability of carrots (Daucus carota L. cv. Eagle) stored for 30 days at 2 °C and 80% relative humidity (RH) (optimal shelf condition (OSC)), 13 °C and 79% RH (common shelf condition (CSC)), or 13 °C and 31% RH (poor shelf condition (PSC)) were monitored. Carrots at PSC lost the most mass followed by those at CSC and OSC. Total water potential (ψ) and osmotic potential (ψπ) of the carrots at CSC and PSC did not change significantly for up to 6 days, but decreased thereafter. No statistically significant change in ψ and ψπ occurred in carrots at OSC. Relative electrolyte leakage (REL) rapidly increased after 12 days at PSC and after 18 days at CSC, at which point mass loss had exceeded 8% of original weight, considered to be a threshold for quality loss. REL of carrots stored at OSC increased only slightly and the mass loss in these carrots did not exceed 8%. Regression analysis showed that mass loss in carrots was consistently associated with REL; changes in ψ and ψπ were associated with mass loss only when carrots were kept at 13 °C. Thus, REL could be a good indicator of mass loss of carrots under a wide range of shelf conditions. The sharp rise in REL at CSC and PSC occurred when the mass loss exceeded 8%.
Postharvest moisture loss characteristics of carrot (Daucus carota L.) cultivars during short-term storage
(Elsevier, 1998-02-13) Shibairo, Solomon I.; Toivonen, Peter; Upadhyaya, Mahesh K.
Differences in moisture loss characteristics among carrot cultivars Imperator Special 58, Gold Pak 28, Caro-pride, Paramount, Eagle, Celloking, Top Pak and Caro-choice during short-term storage at 13 °C and at either 80% or 35% relative humidity were investigated. Experiments were conducted over two years with an early and late harvest in each year. Moisture loss was significantly greater when carrots were stored at low relative humidity compared to high relative humidity. Consistent cultivar differences in moisture loss characteristics were observed only in the late-harvested carrots at low relative humidity. Cultivars with higher specific surface area and relative electrolyte leakage, and lower water and osmotic potentials exhibited high moisture losses. Regression analysis, however, showed that moisture loss differences among cultivars were mainly associated with the specific surface area of the root.
Potassium nutrition and postharvest moisture loss in carrots (Daucus carota L.)
(The Journal of Horticultural Science and Biotechnology, 2015-11-07) Shibairo, Solomon I.; Upadhyaya, Mahesh K.; Toivonen, Peter M. A.
The effect of potassium (K) nutrition on the shelf life of carrots (Daucus carota L., cv. Paramount) was studied using a hydroponic system involving rockwool slabs as an inert support. Carrots were grown for 192 d under greenhouse conditions and with 0, 0.1,1.0,10 and 15 mM K supplied in the nutrient medium. Increase in K concentration in the nutrient medium up to 1 mM decreased postharvest moisture loss. Carrot root weight and tissue K concentration increased, and water potential, osmotic potential and relative solute leakage decreased with increasing K concentration up to 1 mM. Concentrations greater than 1 mM had little or no additional effect on postharvest moisture loss, root water and osmotic potentials and relative solute leakage. Root weight did not increase above 10 mM K. The best subset model obtained by backward stepping and the optimum Mallow’s coefficient showed that carrot root weight and relative solute leakage accounted for most of the variation in moisture loss. Root weight correlated negatively and relative solute leakage positively to moisture loss.
Replacement of postharvest moisture loss by recharging and its effect on subsequent moisture loss during short-term storage of carrots
(American Society for Horticultural Science, 1998-01-01) Shibairo, Solomon I.; Upadhyaya, Mahesh K.; Toivonen, Peter M. A.
Replacing postharvest moisture loss in carrots (Daucus carota L., `Caro-choice') by single and repeated recharging (rehydration in water) treatments, interaction between the duration of recharging and temperature during recharging, and the effects of these treatments on moisture loss during subsequent short-term storage were studied. Carrot mass gain increased with increase in duration of single recharging treatments. Carrots that had lost 2.96% of their mass during storage at 13 °C and 35% relative humidity regained as much as 83% of the mass during recharging for 12 hours. Longer rechargings had little additional effect. Recharging at 13 °C and 26 °C was more effective at replacing water than at 0 °C. The rate of moisture loss (percent per day) during subsequent storage was not affected by recharging duration and temperature during recharging. With repeated recharging every 3.5 days, increase in recharging duration up to 9 hours increased carrot mass gain. Most of the mass gain occurred following 0 to 7 days of storage. These treatments, however, did not affect the rate of moisture loss during subsequent storage. These results suggest that the beneficial effect of recharging on carrot quality is due to replacement of the lost moisture and not to a decrease in moisture loss during storage following recharging. Abrading increased mass loss in non-recharged carrots and increased mass gain during recharging. Recharging should be explored as an option to improve the shelf life of carrots.