Association between Fruit Characteristics and Postharvest Stability of Different Pumpkin (Cucurbita) Species

Abstract

This study aimed at understanding peel and flesh characteristics of Cucurbita maxima Duchesne subsp maxima, Cucurbita pepo L var. fastigata and Cucurbita moschata Decne pumpkin varieties and how the fruit characteristics relate to its postharvest stability. Mature fruits were stored at ambient conditions (28oC and 78% Relative humidity) for eight months. Cell microscopic structure, intercellular space size, sugars, starch, cellulose, hemicellulose, lignin, degree of esterification of pectin, polygalacturonase activity, and cumulative moisture lost were determined monthly. Sucrose, starch, cellulose and hemicellulose content and degree of esterification of pectin of different varieties decreased with storage. Glucose and fructose content increased to a maximum and then reduced. Polygalacturonase activity and lignin generally increased with storage time. Size of intercellular spaces, and cumulative moisture lost from both flesh and peel increased with storage. Sucrose breakdown was key during 0 to 3 months, while moisture loss was important at 4 months of storage. Polygalacturonase activity became paramount from 7th month of storage. Postharvest stability of pumpkins is determined by an interplay of factors. The deterministic factor changes with time. Pumpkin varieties with more lignified peel had lower rates of sucrose breakdown and moisture loss and tended to be more stable postharvest. Varieties with low level of hemicellulose had their cell walls degrade early, while deterioration of pumpkins with highly esterified pectin and closely packed cells was delayed.

Nutritional Variation on Sequentially Harvested Shoots and Fruits of Lagenaria siceraria Landraces

“…The acid detergent lignin (ADL) content accounts for plant parts that are not digestible, where high amounts of ADL reduce the degradation of ADF, NDF, hemicellulose, and cellulose [ 43 ]. Hence, landraces BG-80 at 42 DAS, KSC at 49 and 63 DAS, and BG-100/GC at 56 DAS with low ADL can be selected for high digestibility and readily available nutrients, whereas the landrace KRI across all growth stages (42–63 DAS) had a notably high ADL content, suggesting that the landrace undergoes intense lignification, which results in slow water loss and prolonged shelf life, as observed in C. maxima , C. pepo , and Cucurbita moschata [ 44 ].…”

“…Carbohydrates provide energy to facilitate cellular division and elongation during fruit growth by creating an osmotic pressure gradient, resulting in rapid initial shoot and fruit growth in cucurbits [ 42 ]. Carbohydrates are then stored as starch, which degrades to simple sugars (glucose and fructose) as the fruiting plants age [ 44 ]. As a result, the higher carbohydrate content at 42–49 DAS in comparison to that at 63 DAS across all landraces may be explained by the simple sugars being metabolized into energy and remodified cellular structures in aging fruits [ 42 , 44 ].…”

“…Carbohydrates are then stored as starch, which degrades to simple sugars (glucose and fructose) as the fruiting plants age [ 44 ]. As a result, the higher carbohydrate content at 42–49 DAS in comparison to that at 63 DAS across all landraces may be explained by the simple sugars being metabolized into energy and remodified cellular structures in aging fruits [ 42 , 44 ].…”

Physical, physiological, physicochemical and nutritional characterization of pumpkin (Cucurbita maxima) in postharvest stage cultivated in Antioquia-Colombia

“…However, they are commercially stored outdoors and at room temperature. Some investigations have reported an increase in total soluble solids, a decrease in acidity, beta carotenes and ascorbic acid during storage in environmental conditions of 29±2 °C and 83±7% relative humidity (Nansikombi et al, 2019). These losses reduce the income of medium and small producers, and they occur due to poor postharvest handling, lack of collection centers, inappropriate transportation, poor packaging and storage (Asohofrucol, 2012).…”