Water loss: A postharvest quality marker in apple storage

Apple fruit can be stored for long periods of time, especially with the use of controlled atmosphere storage, but like many fruits and vegetables are susceptible to water loss. Water loss can result in compromised appearance such as skin shriveling, as well as loss of firmness, and reduced saleable weight, which in turn affect the income of growers and other industry stakeholders. Preharvest factors that can influence water loss in apples during the postharvest period include climate, cultivar, fruit size, tree age, orchard practices, and harvest maturity. Postharvest factors such as the storage temperature, relative humidity, storage type, and duration can also affect water loss in apple fruit during storage. The mechanisms of cuticle biosynthesis in water permeance, the role of stomata and lenticels, microcracking, crosstalk with mechanical injuries, storage disorders, and decay incidence during the storage of apples are reviewed. Additionally, the review summarizes: preharvest and postharvest factors influencing water loss; recent management strategies including pre-cooling, cold storage, controlled atmospheres, packaging, and anti-senescence chemicals; the use of edible coatings, as well as other non-chemical approaches for modulating water loss and maintaining storage quality. The review also provides direction for the industry to manage this destructive problem in the postharvest supply chain of apple fruit

Insights into phytonutrient profile and postharvest quality management of jackfruit: A review

Jackfruit (Artocarpus heterophyllus Lam.), also known as ‘vegetarian’s meat’, is an excellent source of carbohydrates, protein, fiber, vitamins, minerals, and several phytochemicals. It is a climacteric fruit that exhibits an increase in ethylene biosynthesis and respiration rate during fruit ripening. The market value of jackfruit is reduced due to the deterioration of fruit quality during storage and transportation. There is a lack of standardized harvest maturity index in jackfruit, where consequently, fruit harvested at immature or overmature stages result in poor quality ripe fruit with short storage life. Other factors responsible for its short postharvest life relate to its highly perishable nature, chilling sensitivity and susceptibility to fruit rot which result in significant qualitative and quantitative losses. Various postharvest management techniques have been adopted to extend the storage life, including cold storage, controlled atmosphere storage, modified atmosphere packaging, edible coatings, chemical treatment, and non-chemical alternatives. Diversified products have been prepared from jackfruit to mitigate such losses. This comprehensive review highlights the nutritional profile, fruit ripening physiology, pre and postharvest quality management, and value addition of jackfruit as well as the way forward to reduce postharvest losses in the supply chain

Insight into the role of melatonin in mitigating chilling injury and maintaining the quality of cold-stored fruits and vegetables

Chilling injury (CI) causes significant losses in fruits and vegetables during cold storage. CI symptoms exhibited as browning, off-flavour and sunken spots, reduced juice content, uneven ripening and softening in fresh horticultural produce. Application of melatonin (MT) effectively mitigates CI in cold-stored fruits and vegetables. This comprehensive review focuses at discussing symptoms, the mechanism of CI, regulation of melatonin-mediated chilling tolerance, and meta-analysis of CI reduction in horticultural produce. Melatonin mitigates CI, maintains quality of cold-stored horticultural produce by upregulating early hydrogen peroxide signalling, activities of antioxidant enzymes after inhibition of reactive oxygen species (ROS) accumulation, mitochondrial dysfunction, and membrane leakage

Trends in maintaining postharvest freshness and quality of Rubus berries

Blackberries and raspberries, commonly known as Rubus berries, are commercially grown worldwide across different climates. Rubus berries contain wide array of phytochemicals, vitamins, dietary fibers, minerals, and unsaturated fatty acids. Nevertheless, these berries have short storage life which is the major constraint in their supply chains leading to higher postharvest losses. Inappropriate harvest handling, physical bruising, insect pests, and postharvest diseases lower the acceptability of fruit among consumers and other supply chain stakeholders. Additionally, the susceptibility to microbial decay, fruit softening, higher ethylene production, respiratory activity, and increased oxidation of anthocyanins, phenolics, and flavonoids considerably affects the marketability of Rubus berries at domestic and international markets. To date, several postharvest strategies such as cold storage, precooling, modified and controlled atmospheres, anti-ripening chemicals, edible coatings, biological agents, and nonchemical alternatives (heat treatment, ultrasound, irradiations, ozone) have been reported to prolong storage life, ensure food safety, and maintain the nutritional quality of Rubus berries. This review briefly encompasses multiple aspects including harvest maturity indices, regulation of fruit ripening, pre and postharvest factors affecting fruit quality, and an update on postharvest quality preservation by employing postharvest technologies to extend the storage life and maintaining the bioactive compounds in Rubus berries which are lacking in the literature. Accordingly, this review provides valuable information to the industry stakeholders and scientists offering relevant solutions, limitations in the application of certain technologies at commercial scale, highlighting research gaps, and paving the way forward for future investigations

Melatonin application suppresses oxidative stress and maintains fruit quality of cold stored ‘Esperanza’ raspberries by regulating antioxidant system

Raspberries are highly perishable and have a short storage life. To extend its storage life, we evaluated the impact of preharvest melatonin (MEL) application (0, 50, 100, 200 mol L−1), three days before harvest, on the activities of oxidative and antioxidative enzymes and quality attributes in ‘Esperanza’ raspberries up to 10 d cold storage. The 200 mol L−1 MEL-treated raspberries exhibited a significant reduction in disease incidence while maintaining higher marketable fruit and activities of superoxide dismutase, glutathione reductase, dehydroascorbate reductase, monodehydroascorbate reductase, ascorbate peroxidase and catalase as compared to control. Additionally, it reduced activities of polyphenol oxidase, peroxidase and lipoxygenase enzymes and increased flavonoids and ascorbic acid levels. However, preharvest spray of 100 mol L−1 MEL mitigated fruit weight loss and maintained higher anthocyanins, and glutathione than control. In conclusion, MEL application (100–200 mol L−1), three days before harvest, supressed oxidative stress by maintaining higher activities of antioxidant enzymes in raspberries during 10 d of cold storage

Oxalic acid: A blooming organic acid for postharvest quality preservation of fresh fruit and vegetables

Oxalic acid (OA) is a unique organic acid that commonly occurs in plants with distinct functions in modulating metabolic processes. To date, the role of OA has primarily been studied in the deactivation of copper-containing preservatives, detoxification of aluminium toxicity and remediation of organic pollutants. During the last two decades, OA has been considered as an antioxidant compound with focus on its potential to enhance crop yield, improve fruit quality, boost nutritional profile, and delay postharvest senescence in fruit and vegetables. It has been established that pre- and postharvest OA application delays ripening and senescence by down-regulating physiological processes such as water loss, ethylene production and respiration. OA treatment controlled adverse storage effects including chilling injury, enzymatic browning, as well as flesh softening by lowering oxidative stress. OA application has also been found to reduce decay in fresh fruit and vegetables by inducing systemic resistance against pathogens, decontamination from surficial microbial load and pesticide residues. Additionally, OA treatments have shown to effectively improve enzymatic and non-enzymatic antioxidants and maintain attributes for eating quality. Effectively, OA application has been deemed to be a potentially food-safe natural and suitable alternative to synthetic chemicals for up-regulating bioactive compounds in harvested fruit and vegetables and extending storability within the postharvest supply chain. This extensive review covers aspects of OA including its: history, chemistry, biosynthesis in plants, quantification in fruit and vegetables, crosstalk with ripening physiology, past attempts and recent advancements in storage life extension, safety as well as quality management of fruit and vegetables

Biological studies into Scedosporium aurantiacum, an opportunistic pathogen colonising human lungs

Thesis by publication.Bibliography: pages 51-85.Chapter 1. Introduction -- Chapter 2. Materials and methods -- Chapter 3. Phenotypic profiling of Scedosporium aurantiacum, an opportunistic pathogen colonising human lungs -- Chapter 4. Pseudomonas aeruginosa inhibits growth of Scedosporium aurantiacum, an opportunistic fungal pathogen isolated from lungs of cystic fibrosis patient -- Chapter 5. Interactions of emerging fungal pathogen Scedosporium aurantiacum with human lung epithelial cells -- Chapter 6. Conclusive summary and future prospects.Scedosporium aurantiacum is a recently identified highly virulent opportunistic pathogen, which is capable of causing a range of infections in immunocompromised people. S. aurantiacum is also known to colonise the respiratory tracts of cystic fibrosis (CF) patients, with a prevalence ranging from 10-17.4% in Australian CF patients. In view of the polymicrobial nature of CF, S. aurantiacum may be frequently encountered with the prokaryotic lung inhabitants such as Pseudomonas aeruginosa. These mixed bacterialfungal interactions or interactions between the fungus and the host lungs may impact the outcome of CF.In this study, a high throughput microtitre plate-based nutrient utilisation assay involving 94 unique substrates was used to characterise four S. aurantiacum strains displaying different virulence levels as determined by the Galleria mellonella larvae model. This approach unveiled five carbohydrate metabolism pathways and a difference in the sucrose and turanose metabolism between high and low virulence S. aurantiacum strains. One high and one low virulence strain were further co-cultured with clinical CF isolates of P. aeruginosa in a medium mimicking human CF sputum to explore the mechanisms of interactions between P. aeruginosa and S. aurantiacum using plate tests and confocal fluorescence microscopy. A genetic transformation system was also developed for S. aurantiacum to facilitate detailed observation of the bacterial-fungal interactions. In liquid cultures, the biofilm forming strains of P. aeruginosa exhibited a higher inhibitory effect against growth of S. aurantiacum compared to the non-biofilm forming strains. These results indicated that the ability to form biofilms might be useful for P. aeruginosa to cause inhibition of S. aurantiacum growth when in direct contact with the fungus. However, these biofilm forming P. aeruginosa strains could inhibit the growth of S. aurantiacum strains even in the absence of a direct physical contact i. e. in co-cultures involving separating membranes. These results suggest that in addition to biofilm formation, P. aeruginosa could also utilise diffusible extracellular metabolites for inhibiting the fungal growth.Further on, respiratory epithelial cells derived from a lung carcinoma were infected with a high virulence S. aurantiacum strain and the response of cells was determined using electron microscopy and transcriptomics-based approaches. S. aurantiacum invaded the respiratory epithelial cells by an initial adherence to the cell surface followed by penetration into the cell using conidial germ tubes. The respiratory cells exhibited a protective response against the fungal infection by up-regulating the inflammatory pathways leading to the release of cytokines.n conclusion, this work expands the existing knowledge of the emerging fungal pathogen S. aurantiacum and thus provides valuable insights into its yet unanswered role in CF, ultimately leading to a better understanding of pathophysiology of the disease.Mode of access: World wide web1 online resource (xvii, 175 pages) illustrations (some colour

CORRECT-CREATE Mobility to UWO

The CORRECT-CREATE program has provided me with an opportunity to learn valuable research skills. I would like to say Thanks to my supervisor Dr. Janine Mauzeroll and my hosts, Dr. Mark Biesinger and Dr. Yolanda Hedberg for their support during this journey. This awesome journey at Surface Science Western and University of Western Ontario has helped me to endeavor knowledge of XPS peak fitting. I would also like to appreciate the support of Dr. Jeffrey Henderson who taught me a lot during this journey

Two Cases of Crystal-storing Histiocytosis Diagnosed by Morphology, Immunohistochemistry, and Ultrastructural Examination.

Crystal-storing histiocytosis (CSH) is a non-neoplastic histiocytic proliferation containing crystalline material, usually associated with an underlying lymphoproliferative or plasmacytic disorder. The crystalline structures are typically derived from kappa light chain immunoglobulins. The lesions of CSH are comprised of sheets of histiocytes with abundant eosinophilic cytoplasm containing variably prominent, elongated crystals. This rare phenomenon is important to recognize, as it is known to morphologically obscure an underlying neoplasm. Histologically, the cells of CSH may closely mimic Gaucher cells, as well as the pseudo-Gaucher cells sometimes encountered in chronic myeloid leukemia. The distinction between the cells of CSH and that of histologic mimics may be made more definitively through the use of electron microscopy, as the crystalline inclusions seen in CSH display characteristic size, shape, and localization within the cells. Here, we report 2 rare cases of CSH diagnosed by morphology, immunohistochemistry, and ultrastructural examination. The first case presented was diagnosed concurrently with plasma cell myeloma, and the second case discussed was diagnosed in association with marginal zone lymphoma

Interactions of an Emerging Fungal Pathogen Scedosporium aurantiacum with Human Lung Epithelial Cells

Abstract Scedosporium fungi are found in various natural and host-associated environments, including the lungs of cystic fibrosis patients. However, their role in infection development remains underexplored. Here the attachment of conidia of a virulent S. aurantiacum strain WM 06.482 onto the human lung epithelial A549 cells in vitro was visualized using microscopy to examine the initial steps of infection. We showed that 75–80% of fungal conidia were bound to the A549 cells within four hours of co-incubation, and started to produce germ tubes. The germinating conidia seemed to invade the cells through the intercellular space, no intracellular uptake of fungal conidia by the airway epithelial cells after conidial attachment. Transcriptomic analysis of the A549 cells revealed that the up-regulated genes were mainly associated with cell repair and inflammatory processes indicating a protective response against S. aurantiacum infection. Network analysis of the differentially expressed genes showed activation of the innate immune system (NF-kB pathway) leading to the release of pro-inflammatory cytokines. We believe this is the first report showing the transcriptomic response of human alveolar epithelial cells exposed to S. aurantiacum conidia paving a way for better understanding of the mechanism of the infection process