The quality of citrus fruit is influenced by various growing conditions, including weather. However, the impact of weather differences between growing regions on citrus quality at harvest is not well understood. This study utilizes a mechanistic-driven digital replica of the growth process of a Valencia orange from fruit set until harvest to quantify this impact. The temperature, humidity, rainfall, and vapor pressure deficit data from different orange growing regions of South Africa, including Citrusdal, Nelspruit, Letsitele, and Sundays River Valley (SRV), are compared. The results suggest that the differences in weather conditions between growing regions affect fruit diameter (FD), fruit weight (FW), rind thickness (RT), rind weight (RW), total soluble solids (TSS), and titratable acidity (TA) of oranges at harvest. The differences between growing regions led to variations of up to threefold for FD, twofold for FW, RT, RW, TSS, and up to fourfold for TA upon harvest. Notably, oranges produced from warmer Letsitele and Nelspruit regions are found to be larger and less acidic compared to those from coastal SRV upon harvest. The study also reveals the impact of the fruit growth process on the temperature gradient within the fruit, which varies across growing regions. The maximal temperature difference between the fruit core and surface during the growth process ranges from 2 °C to 3 °C. These variations in fruit temperature gradient could lead to variations in temperature-driven quality decay of fruit from different climatic regions at the start of their postharvest journey. These findings provide valuable insights for the citrus industry, optimizing practices, harvest planning, and postharvest logistics. The output of this digital twin will help identify areas needing extra precooling to extend shelf life and minimize quality decay. Real-world use allows growers to schedule harvests based on regional weather conditions.

10.31224/3337

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Inefficiency in land-side cold-chain logistics: Solutions to improve the handling of citrus during preparation for cold-treatment protocols

Social Sciences & Humanities Open (2023)

Gculisile Khumalo Leila L. Goedhals-Gerber Paul Cronjé Tarl Berry

This article aims to address the question of how current citrus handling can be improved to ensure fewer occurrences of non-conformances. Citrus fruit contributes 60% of fruit export volumes in South Africa, with revenue of approximately R20 billion per annum. The high export volumes translate to difficulties such as road transport and cold-storage congestion, reefer container shortages and port delays. The increase in the export volumes also highlights inefficiencies, such as temperature variability, that occur due to delays during logistical cold-store processes. Cold stores are responsible for cold-treatment preparation processes such as forced-air cooling and the loading of fruit at protocol temperature. This study assessed the crucial stages to maintain the required temperature protocols during land-side processes by studying various controlled shipments. The results show that temperature variability occurs during pre-cooling and container loading, which might have an effect on fruit quality. Once the cold-treatment process commences, the step-down approach is applied and temperature is well maintained. The study linked the identified inefficiencies in land-side cold-chain logistics to temperature protocol failures along the cold chain. It also identified the factors that affect temperature variability in cold stores. The study's recommendations can be used to inform the regulatory body's policy, which is responsible for the exportation of fruit in South Africa. Specifically the recommendation pertaining to an increase in the number of hours that citrus pallets are cooled prior to shipment. This will aid with reducing temperature variability and ensure successful cold treatment shipments.

Cold chain

Pallet

Economic shortage

Cold start (automotive)

10.1016/j.ssaho.2023.100500

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Citations (3)

Artificial fruit for monitoring the thermal history of horticultural produce in the cold chain

Journal of Food Engineering (2017)

Thijs Defraeye Wentao Wu Kevin Prawiranto Giuseppino Fortunato Shelley Kemp

10.1016/j.jfoodeng.2017.07.012

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Nonchilling Physiological Rind Disorders in Citrus Fruit

Lembe Samukelo Magwaza Umezuruike Linus Opara Paul Cronjé Sandra Landahl Leon A. Terry

Appearance is the primary parameter used to evaluate the quality of citrus fruit for the fresh market; so the condition of fruit rind is an important quality attribute. Preventing the development of nonchilling physiological rind disorders such as rind breakdown, rind pitting, rind staining, puffiness, and peteca spots is one of the key challenges in postharvest handling of citrus fruit. Intensive research has been conducted toward better understanding of the factors contributing to the incidence of these disorders. This chapter examines the preharvest and postharvest factors contributing to the incidence and severity of nonchilling physiological rind disorders in citrus fruit, and presents a physical characterization of these disorders. It also describes the molecular, biochemical, and physiological basis of rind disorders and highlights the techniques for inducing rind disorders for research investigations. To date, the mechanism of citrus rind pitting disorder and the relationship with other physiological rind disorders is not well understood. However, it has been established that fruit susceptibility to these disorders is influenced by the microclimate inside the fruit canopy. The prospects for biochemical markers to predict the development of rind disorders and the use of nondestructive technologies to sort affected fruit are discussed in the chapter.

Preharvest

10.1002/9781118707418.ch03

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Citations (21)