CERES :: Browsing by Author "Terry, Leon A."

Browsing by Author "Terry, Leon A."

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Open Access
Antiviral and quality effects of chemical elictors and Cucumber Mosaic Virus (CMV) infection on tomato plants and fruits
(Cranfield University, 2012-05) Kalogirou, Maria; Terry, Leon A.; Varveri, Christina
Cucumber mosaic virus (CMV) has emerged as one of the most serious threats to tomato cultivation in Greece. In the present study the effects of Benzothiadiazoles (BTH) and pyraclostrobin against mechanically or aphid-transmitted CMV in tomato plants, of hybrid F1 Clodin, were investigated in greenhouse experiments. BTH was confirmed as capable of inducing systemic acquired resistance (SAR) in tomato seedlings against CMV, while pyraclostrobin was not. Responses to BTH application and/or CMV inoculation on Spanish tomato hybrid Delos (BTH, BTH+CMV, CMV treatments) were monitored during winter and spring season in Greece. In both seasons the SAR derived from BTH application suppressed CMV. BTH treatment presented increased plant growth, fruit size and marketable tomato yield compared to CMV and BTH+CMV treatments, whereas decreased compared to healthy control. CMV treatment caused the most severe stunting of tomato plants among the examined treatments and resulted in yield loss of marketable fruits, although the total fruit number was higher versus to other treatments. Cont/d.
Open Access
Biochemical and biomedical studies on African walnut (Tetracarpidium conophorum -Mull. Arg.) – a postharvest perspective
(Cranfield University, 2015-10) Nkwonta, Chikere Godwin; Terry, Leon A.; Cellek, Selim; Alamar, M. Carmen
African Walnut (Tetracarpidium conophorum- Mull. Arg) is a perennial climbing shrub which grows mainly in the Western region of Africa. It is found mainly in Nigeria, Gambia, Sierra Leone, Gabon, Equatorial Guinea and Cameroon as well. The nuts are encased in pods which may contain between 2 to 5 nuts. The seed is enclosed in a hard shell-like case. The nuts are commonly processed by boiling or roasting and consumed as a snack or used as soup thickener. In ethnobotanical medicine, the nut extract is extensively used in decoctions for treatment and/or management of common and chronic ailments such as malaria, dysentery, high blood pressure, diabetes and cancer. The nuts are generally exposed to high temperatures (25 – 37 °C) and relative humidity (RH) which increases susceptibility to fungal contamination and nutrient degradation, hence, raising concerns over product quality and safety. Experiment simulating the common retail postharvest storage and processing practices was conducted to: (i) determine the effects on the fatty acid profile; (ii) assess the impact on the fungal population contaminating the nut shells at different maturity stages, and potential mycotoxigenic implications; (iii) evaluate the cytotoxicity of four extract of the nut on lung cancer (A549) cells; and finally (iv) assay the total phenolic content and profile potential individual phenolic components of the nut. Results indicated the presence of essential and non-essential fatty acids namely; palmitate, oleate, stearate, linoleate, arachidate and α-linolineate with α-linolineate being the most abundant (1.1 – 8.2 mg/g freeze-dry weight). Boiling and roasting generally improved the concentration of the fatty acids best when nuts are cold stored at 5 °C for maximum of 10 days. Potential mycotoxigenic species - Aspergillus section Nigri, Aspergillus flavus/Parasiticus, Fusarium spp. and Penicillium spp. - were frequently isolated from cultured shell pieces of stored nuts. When compared with unprocessed nuts, roasting completely prevented fungal contamination in shell pieces from nuts in the non-stored (NSN) group at early maturity stage, while boiling significantly reduced the level of contamination to about 58 % (P < 0.05). Simulating open market conditions caused 100% fungal contamination in all boiled samples and roasted samples at early maturity. Mycotoxin analysis using Yeast Extract agar (YES) and High Performance Liquid Chromatography (HPLC) - Fluorescence detector (FLD) showed that Aflatoxins - G1 (AFG1), B1 (AFB1), G2 (AFG2), and B2 (AFB2) were produced by 20 isolates with both AFG1 and AFB1 being predominant at concentration ranges 4 – 32,200 and 4 – 22,700 ng/g plug weight, respectively. No Ochratoxin A (OTA) was detected. Phenolic component analysis indicated unprocessed (20.79 ± 1.0 mg gallic acid equivalent per gram freeze-dry weight – GAE/g FDW) samples showed the highest value for total phenolics while both boiling (9.90 ± 1.8 mg GAE/g FDW), and roasting (9.32 ± 2.7 mg GAE/g FDW) reduced the amount by more than 50 % when compared with unprocessed. Potential individual phenolic compounds were unambiguously separated using high performance liquid chromatography – diode array detector (HPLC-DAD). There were no differences between chromatograms of defatted and non-defatted unprocessed, roasted and boiled samples. Cytotoxicity evaluation showed no decrease in cell densities in plates treated with extracts from unprocessed nuts at all concentrations. Diethyl ether-ethyl acetate (10 µg/mL) and n-butanol (1000 and 500 µg/mL) extracts of roasted nuts as well as dichloromethane and water (1, 10 µg/mL) of boiled nuts caused a non-significant decrease of < 10 % in cell densities when compared with the phosphate buffered saline-media control. However, all extracts showed no cytotoxic effect on the A549 cells African walnut is basically produced at subsistence level in Nigeria, but considering the presence of desirable fatty acid profile and phenolic compounds, need for increased industrial scale production is herein recommended. Although fungal attack and potential mycotoxin risk on the nut may be high, retail processing by roasting has prospects to greatly accentuate the risk. Cold storage of the nut may help to improve the shelf life although it may not be cost effective for local farmers in Nigeria and Africa, however, it provides opportunity for export business. Although the nut extracts showed no cytotoxic effect on A549 lung cancer cell lines, there is need to investigate further to confirm it non-cytotoxicity activity on other cancer lines and normal cell lines.
Open Access
Biology and management of freesia flower specking caused by Botrytis cinerea
(Cranfield University, 2003) Darras, Anastasios I.; Joyce, Daryl C.; Terry, Leon A.
There is no published research regarding postharvest infection of freesia flowers by Botrytis cinerea. Although, infection problems have concerned freesia growers and wholesalers in recent years. The overall objectives of this study were firstly to evaluate the factors affecting B. cinerea postharvest disease establishment and secondly to evaluate a range of novel potential treatments to reduce postharvest freesia infection. These treatment options include plant activators such as acibenzolar-S-methyl and methyl jasmonate and biotic (Aureobasidium pullulans) and abiotic (UV-C irradiation) biological/elicitors agents. Research was undertaken in an attempt to explain the variation in B. cinerea incidence on cut freesia flowers as noted by the UK importer Zwetsloots & Sons Ltd. in 2000. Higher monthly rejections of freesia flower stems throughout 2000 due to B. cinerea infection were recorded during spring (April-May), early summer (June) and autumn (October). Comparatively higher proportions of rejected freesia stems were associated with glasshouse temperatures ranging from 13-17°C. In the presence of B. cinerea inoculum on freesia petal surface, temperature was not a limiting factor for disease establishment. Incubation of artificially inoculated freesia flowers at 12°C resulted in overall higher disease severity and lesion numbers compared to flowers incubated at 5 or 20°C. In contrast, relative humidity was the most important factor for postharvest infection by B. cinerea. Elicitor based strategies for IPM using the potent activator acibenzolar provided limited protection of freesia flowers against B. cinerea when applied postharvest. Acibenzolar significantly reduced disease severity, lesion numbers and lesion diameters compared to the untreated control when applied at 0.15 g A. 1. U1. Methyl jasmonate (MeJA) applied as gas, pulse and spray generally suppressed B. cinerea disease on cut freesia flowers. Disease severity, lesion numbers and lesion diameters of flowers gassed with 0.1 μL MeJA L"' were reduced by 56,43 and 37%, respectively compared to untreated control flowers. Gaseous MeJA treated freesia flowers at 0.1 μL L"1 increased PPO activity by 57% compared to untreated controls 24h after MeJA treatment. After 36h of incubation at 20°C, disease severity, lesion numbers and lesion diameters of gaseous MeJA treated flowers were reduced by 68,56 and 50%, respectively, compared to the untreated controls. However, PAL activity in MeJA treated freesia flowers did not decrease significantly over time compared to untreated control 12h post-inoculation and thereafter. These findings suggest that MeJA treatment might suppress the action of PAL in the phenylpropanoid pathway and consequently block SA production. UV-C irradiation might be used in an integrated postharvest disease management program for freesia flowers. UV-C irradiation after artificial inoculation resulted in markedly reduced B. cinerea disease severity scores and lesion numbers. In detail, UV-C irradiation of cut freesia flowers with 0.5,1,2.5 and 5 kJ m''` reduced disease severity by up to 44,70,74 and 59% and lesion numbers by up to 37,62,68 and 60%, respectively. UV-C irradiation at 1 kJ M-2 before artificial inoculation slightly reduced disease severity and lesion numbers possibly by inducing defence responses. However, the limited disease suppression suggested that apparently B. cinerea could overcome the UV-C induced effect. The effect of preharvest treatments on freesia crops with acibenzolar was investigated in glasshouse trials in view to suppress postharvest B. cinerea infection via SAR induction. Acibenzolar was effective in selected treatments and conditions. Disease pressure varied over the 3 years and over varieties tested. However, it was unclear whether acibenzolar induced systemic and/or local defence responses. The latter was supported by biochemical investigations in 2001 which suggested that acibenzolar did not induce PAL activity. In contrast, preharvest MeJA treatment resulted in markedly systemic protection of treated flowers compared to untreated ones. MeJA efficacy was dependent on variety and on postharvest incubation temperatures. Disease severity, lesion numbers and lesion diameters on MeJA treated freesia var. `Dukaat' flowers incubated at 20°C were reduced by 56,61, and 49% compared to controls, respectively. Also, disease severity, lesion numbers and lesion diameters on MeJA treated `Cote d'Azur' flowers incubated at 20°C were reduced by 36,26, and 49% compared to controls, respectively.
Open Access
Controlled atmosphere as cold chain support for extending postharvest life in cabbage
(Elsevier, 2024-11-01) Gage, Ewan; Jain, Ritika; Terry, Leon A.; Falagán, Natalia
Postharvest management of cabbage relies on high-intensity cooling to control postharvest physiology, minimising quality loss despite incurring significant energy and environmental costs. As an alternative, we hypothesised that controlled atmosphere (CA) could allow increased storage temperature by supporting physiological regulation, while maintaining quality and reducing energy demand. This study examined the effect CA (1.5 kPa CO2 and 6 kPa O2) at 5 or 10 °C on cabbage quality, with the aim of proposing a more sustainable and resilient supply chain. CA treatment was effective at reducing head respiration at higher temperature, with CA/10 °C treatment achieving lower respiration rates than Control/5 °C. Improved head colour retention and maintenance of stump quality were observed in cabbage under CA conditions. CA effects were seen also at a regulatory level; CA promoted an average of 25.4% reduction in abscisic acid accumulation potentially as part of a wider hypoxia stress response and was successful in decreasing expression of the senescence-coordinating transcription factor BoORE15. This finding was linked with a lower in downstream expression of pheophytinase and subtilisin protease. These results demonstrated that CA treatment fundamentally modified postharvest physiology in cabbage, which can be exploited to enable storage at warmer temperatures, contributing to supply chains with lower energy demand and its associated environmental benefits.
Open Access
Development of a Botrytis specific immunosensor: towards using PCR species identification
(Cranfield University, 2014-01) Binder, Michael; Terry, Leon A.; Tothill, Ibtisam E.
Botrytis species affect over 300 host plants in all climate areas of the world, at both pre and post-harvest stages, leading to significant losses in agricultural produce. Therefore, the development of a rapid, sensitive and reliable method to assess the pathogen load of infected crops can help to prescribe an effective curing regime. Growers would then have the ability to predict and manage the full storage potential of their crops and thus provide an effective disease control and reduce post-harvest losses. A highly sensitive electrochemical immunosensor based on a screen-printed gold electrode (SPGE) with onboard carbon counter and silver / silver chloride (Ag/AgCl) pseudo-reference electrode was developed in this work for the detection and quantification of Botrytis species. The sensor utilised a direct sandwich enzyme-linked immunosorbent assay (ELISA) format with a monoclonal antibody against Botrytis immobilised on the gold working electrode. Two immobilisation strategies were investigated for the capture antibody, and these included adsorption and covalent immobilisation after self-assembled monolayer formation with 3-dithiodipropionic acid (DTDPA). A polyclonal antibody conjugated to the electroactive enzyme horseradish peroxidase (HRP) was then applied for signal generation. Electrochemical measurements were conducted using 3,3’, 5,5’-tetramethylbenzidine dihydrochloride / hydrogen peroxide (TMB/H2O2) as the enzyme substrate system at a potential of -200 mV. The developed biosensor was capable of detecting latent Botrytis infections 24 h post inoculation with a linear range from 150 to 0.05 μg fungal mycelium ml-1 and a limit of detection (LOD) as low as 16 ng ml-1 for covalent immobilisation and 58 ng ml-1 for adsorption, respectively. Benchmarked against the commercially available Botrytis ELISA kits, the optimised immuno-electrochemical biosensor showed strong correlation of the quantified samples (R2=0.998) ... [cont.].
Open Access
Discovering biomarkers of postharvest resilience and flavour life in imported citrus and table grapes.
(Cranfield University, 2022-02) Navarro-Calderon, Angela; Alamar, M. Carmen; Terry, Leon A.
Clementines and table grapes, which are the main fruit crops consumed in the UK after bananas and apples, are considered non-climacteric fruit, not showing an increase in respiration rate and ethylene production during ripening. Previous research has suggested that a different ripening hormone, abscisic acid (ABA), has a more crucial role in the ripening of this kind of produce. The study presented herein aimed to identify biomarkers of postharvest resilience and flavour life of imported clementines and table grapes. For these studies two experiments were designed with the common objectives of determining: 1) the pre- or postharvest factors influencing the postharvest produce quality – both physiological and biochemical, and 2) the role of ABA and ABA catabolites on fruit senescence. The main findings from these studies were that the canopy position of clementines significantly affected fruit postharvest quality and hormonal content. Fruit located on the inside canopy showed higher RR and lower sugar content than outside fruit at the end of postharvest storage, resulting in a shorter shelf- life. At the same time, inside fruit showed a higher content of ABA and ABA catabolites than outside fruit, coinciding with a lower consumer preference score for external appearance, aroma and flavour. This is the first study that determined the ABA and ABA catabolite contents in the pulp of clementines from different canopy positions during senescence, and related this to consumer acceptance. The use of an ethylene inhibitor, 1-methylcyclopropane (1-MCP), during the postharvest storage of table grapes was investigated. The treatment did not have a positive effect on their postharvest quality; in fact, grapes were significantly affected by mould incidence at the end of the shelf-life. The hormonal content in different berry sections was also evaluated; the distal section, which showed a higher mould incidence than the proximal, had three times more ABA and ABA catabolites than the proximal section. This is the first time that the spatial distribution of ABA during the senescence of table grapes was profiled. Despite being different products, similar novel results were observed for both clementines and table grapes. This study indicated that senescence processes in these non-climacteric produce was initiated after a significant increase in RR, and that ABA could be considered a biomarker for clementines and table grapes senescence since an ABA peak during postharvest storage preceded an increase in RR, mould incidence, organic acids, and sucrose hydrolysis. This coincided with a decrease in berry firmness. These findings are of significant importance for the industry. Understanding how ABA regulates senescence processes and the quality changes taking place during postharvest cold storage of clementines and tables grapes improves the consistency in fruit quality and reduces waste and consumer complaints. Although clear beneficial findings have been identified, the results of this study were limited by time, resources, climatic conditions, and other factors. Therefore, recommendations for future work are: to perform molecular studies on genes regulating the ABA pathway from field to postharvest storage; to investigate the crosstalk between ABA, ethylene, and sucrose from ripening to senescence; and to further investigate the use of shade nets and harvesting by canopy position on fruit quality consistency and consumer acceptance.
Open Access
Discrimination of Allium headspace volatiles affected by variations in genotype growing environment and storage using an electronic noses
(2003) Abbey, Lord; Joyce, Daryl C.; Terry, Leon A.
Alliums are valued mainly for their unique organosulphur-derived flavours and aromas. Traditional sensory and analytical determinations of Allium quality are constrained by high cost, technical difficulties and, time and human limitations. This thesis investigates the potential for use of relatively novel electronic nose (E-nose) technology for Allium discrimination. Chapters 3, 4 (Sections 4.1 to 4.3), 5 (Sections 5.1 and 5.2) and Appendices II and III inclusive have been published or submitted for publication. Consequently, Chapters in this thesis are presented in the form of papers. The E-nose AromaScan LabStation A32/8S (Osmetech Pic., UK) consists of 32 conducting polymer miniature sensors. Adsorbed odour molecules alter the electric conduction mechanism of the sensor polymer. The response is measured as proportional (%) change in sensor resistance ratio (%dR/R). The E-nose discriminated Allium types (Chapter 3), varieties of spring onion grown with or without sulphur addition and a single variety of spring onion grown under different levels of sulphur, nitrogen, water-deficit stress and soil type (Chapter 4). Bulb onion affected by nitrogen, sulphur and soil type and diced onion sealed in polyethylene bags stored at 4°C for 9 days were also discriminated by the E-nose (Chapter 5). A descriptive model for the direction of E-nose sensor polymer response to Allium headspace volatiles affected by genotypic differences and edaphic variables was outlined in Section 6.2. Principal Component Analyses (PCA) of E-nose data sets output accounted for >75% to nearly 100% of variations in the Alliums. The variations in Allium genotype differentially affected the E-nose sensor conductivity following headspace volatiles interaction with sensor polymer element. Classification of data sets output showed greater (Mahalanobis distance statistic, D² >3.0) sensitivity of spring onion cvs Guardsman and Fragrance to S fertilisation while the headspace volatiles characteristics of cvs Winter Over and Paris Silverskin were not significantly (D²<3.0) altered by S. The headspace volatiles of onion bulb cv. Sprinters also responded to S fertilisation (D²>3.0) and thus, increased %dR/R. Overall, N-fertilised onion cv. Sprinters reduced E-nose sensor conductivity leading to an increase in %dR/R. Increases in water-deficit stress i.e. > -0. 80 MPa soil water potential, SWP generally reduced separation between E-nose data set clusters for clay versus sandy loam soils from D² = 43.2 for -0.01 MPa SWP to D² = 6.2 for -1.19 MPa. Headspace volatiles of onions grown in the glasshouse clay increased %dR/R compared to reduced %dR/R values for both glasshouse and field sandy loam soils. The E-nose detected gradual changes in headspace volatiles of diced onion wrapped in polyethylene bags stored at 4°C for 9 days. The changes in headspace volatiles reduced %dR/R values while data set cluster separations with reference to day 0 for each sampling time increased from D² = 3.6, 5.8 and 7.0 on days 3, 6 and 9, respectively. The results suggested that Allium quality can be assessed with ease along production, postharvest and marketing chains compared to traditional destructive methods. Linear correlations for E-nose data sets versus Allium pungency determinants (pyruvic acid and lachrymatory potency), total soluble solids and dry-matter were poor. The thesis discusses the commercial significance of the result and its implication for the development of E-nose sensor tailored for Alliums. This would promote application and use of E-nose technology in the Allium industry, germplasm evaluation, and discrimination of agronomic variables and possibly, monitoring spoilage pathogens during storage. The effects of nitrogen, sulphur, water-deficit stress and soil type and their interactions have given new insight into agronomic inputs on growth and microbial load (Chapters 4.3, 5.1 and Appendix III).
Open Access
Disposable pyruvate biosensors for routine assessment of onion flavour
(Cranfield University, 2007-04) Abayomi, Louise Anike; Terry, Leon A.
The UK-grown onion sector shows strong potential for growth through new product development as consumers become increasingly aware of the health and dietary benefits of fresh onion consumption. Prospects for the production of new, more palatable sweet onions will be boosted by the development of improved grower diagnostics for flavour standardisation. Growers require simple-to-use on-farm diagnostics to assure flavour quality. The introduction of pungency tests has led to increased mild onion sales, however currently tests are out-sourced and as a result costly. Through this Defra- (Department for Agriculture Food and Rural Affairs) sponsored research project (HL0164), hand-held biosensor technology, adapted from the medical sector, has been developed for improved and lower cost pungency and sweetness analysis in onions. Cont/d.
Open Access
Effect of controlling ethylene on ripening of avocado cv. hass fruit
(Cranfield University, 2010-05) Meyer, Marjolaine D.; Terry, Leon A.
Rigorous control of ethylene inside storage atmosphere is cardinal to maintain quality of climacteric fruit, including avocado cv. Hass. This can be achieved using the ethylene action inhibitor, 1-methylcyclopropene (1-MCP). The recent development of a novel palladium (Pd)-based ethylene scavenger, e+® Ethylene Remover, provides a new opportunity to delay avocado fruit ripening. A new method was developed to sequentially extract and quantify both lipids and sugars from the same avocado mesocarp tissue sample. Extraction by homogenization with hexane yielded slightly less oil than the standard Soxhlet technique whilst the fatty acid profiles of the oil extracts were similar. Extraction of the resulting filter residue with methanol (62.5%, v/v) better recovered sucrose, perseitol and mannoheptulose as compared to ethanol (80%, v/v). The new method has a shorter extraction time, lower extraction temperature and requires less solvent. Presence of e+® Ethylene Remover in storage atmosphere removed all ethylene and accordingly delayed the ripening of avocado cv. Hass stored at low temperature. 1-MCP also inhibited ripening, yet, unlike e+® Ethylene Remover it impaired subsequent ripening. It was possible to slow down the ripening rate after the climacteric has been induced by removing ethylene below 1 μL L-1 in presence of e+® Ethylene Remover, and the scavenger was effective in combination with modified atmosphere packaging (MAP). Blocking ethylene action or removing ethylene did very slightly affect the fatty acid composition of the mesocarp oil. Depending on the origin and maturity of the fruit, 1-MCP and e+® Ethylene Remover better maintained seven-carbon sugars concentrations in mesocarp. Results support the view that mannoheptulose and perseitol could be important features of the avocado ripening process but more research is necessary to elucidate their exact function. Mesocarp abscisic acid (ABA) was quantified using a newly developed LC-ESIMS/ MS method. ABA increased as fruit ripened but appeared to be at least partly regulated by ethylene. Whether ABA influences the ethylene-associated ripening in avocado cv. Hass remains to be determined in future.
Open Access
Effect of temperature, relative humidity, and incubation time on the mycotoxin production by Fusarium spp. responsible for dry rot in potato tubers
(MDPI, 2024-10-01) Gutiérrez-Pozo, Maria; Verheecke-Vaessen, Carol; Kourmpetli, Sofia; Terry, Leon A.; Medina, Angel
Potato is the fourth most consumed crop in the world. More than half of the crop is stored for three to nine months at cold temperatures (3–10 °C) for the fresh and seed market. One of the main causes of fresh potato waste in the retail supply chain is the processing of fungal and bacterial rots during storage. Dry rot is a fungal disease that mainly affects the potato crop during storage and is responsible for 1% of tuber losses in the UK. It is produced by Fusarium spp., such as Fusarium sambucinum and F. oxysporum, which can lead to the accumulation of mycotoxins in the potato tuber. Little is known about the impact of environmental factors on the accumulation of mycotoxins in potato tubers. Understanding the ecophysiology of these fungi is key to mitigating their occurrence under commercial storage conditions. Therefore, this work aimed to elucidate the effect of three different temperatures (5, 10, and 15 °C) and two different water activities (aw; 0.97, 0.99) on the ecophysiology and mycotoxin accumulation of F. sambucinum and F. oxysporum in a potato-based semi-synthetic medium. The mycotoxin accumulation was then studied in vivo, in potato tubers cultivated under organic farming conditions, stored for 40 days at 8.5 °C. Results showed that higher temperatures and aw enhanced fungal growth, lag time, and mycotoxin accumulation in vitro. Growth rate was 2 and 3.6 times higher when the temperature increased from 5 to 10 and 15 °C, respectively. Six different mycotoxins (T-2, HT-2, diacetoxyscirpenol, 15-acetoxyscirpenol, neosolaniol, and beauvericin) were detected in vitro and in vivo. T-2 was the most abundant mycotoxin detected in vitro, observing 106 ng of T-2/g media after 21 days of incubation at 10 °C and 0.99 aw. Due to the long period of time that potato tubers spend in storage, the fluctuations of environmental factors, such as temperature and relative humidity, could promote the development of fungal rot, as well as mycotoxin accumulation. This could result in important food and economic losses for the potato market and a threat to food safety.
Open Access
The effects of controlled atmosphere and ethylene on the postharvest quality of sweet potato during storage.
(2018-04) Sowe, Sulaiman; Terry, Leon A.; Thompson, Andrew J.
Sweet potato (Ipomoea batatas Lam) is the third most important food commodity in Sierra Leone and global demand for the commodity is growing. To meet this demand requires the use of effective storage methods due to the perishability (shrivelling, sprouting and disease) of the root after harvest. This study therefore investigated the efficacy of controlled atmosphere (CA) and ethylene on the physiological, biochemical, mycological and molecular dynamics of sweet potato during storage. This was done by storing sweet potato samples (cultivar: 06-52; known as Belle Vue in the USA) at 20˚C as follows: CA (5 kPa CO₂ and 8 kPa O₂), air (0.003 kPa CO₂ and 21 kPa O₂), CA supplemented with 0.001 kPa ethylene and continuous exogenous ethylene (0.001 kPa) for a maximum of 12 weeks. A transition phase was established at six weeks of storage which involved swapping of treatments from CA with and without supplemented ethylene to air storage and vice versa (Experiment 2) and that from ethylene to air storage and vice versa (Experiment 4). Results showed that in as much as the ethylene supplementation was successful in supressing sprouting, the contents of phenolics and sugars increased as well as weight loss and respiration rates, which undermine its positive aspects. Storage in CA reduced weight loss and respiration rates but did suppress sprouting as well. The complete inhibition of sprouting during storage could also be attributed to decreased biosynthesis of the cytokinin, trans-zeatine riboside (trans-ZR) in the sweet potato due to ethylene supplementation. Also ethylene induced rise in phenolics corresponded with an increased relative expression of ethylene response factors (ERF) in the proximal section unlike the reducing sugars. The ERF gene was more expressed towards the end of storage whilst ethylene insensitive 2 (EIN2) was more expressed at the beginning which suggested that EIN2 was actively repressed during storage particularly under CA treatment. Furthermore, continuous CA storage was effective in mitigating disease development on the sweet potato as well as in controlling Penicillium development but not that of Fusarium. Major diseases identified on the sweet potato were Fusarium surface rot and Rhizopus soft rot predominantly at the proximal and distal sections mainly during storage under ethylene supplemented CA. The mycotoxin, aflatoxin G1 was the most predominant potentially produced aflatoxin on the sweet potato and continuous CA was very effective in inhibiting the potential contamination of all the studied aflatoxins: aflatoxin B1 (AFB1), aflatoxin B2 (AFB2) and aflatoxin G1 (AFG1) during storage.
Open Access
The effects of ethylene on sweetpotato storage
(Cranfield University, 2014-01) Amoah, Robert Sarpong; Terry, Leon A.
Sweetpotato (Ipomoea batatas (L.) Lam.) is an important food security crop in many parts of the developing world. Despite its economic value and growing contribution to nutrition and health in tropical and sub-tropical countries, sweetpotato has a short postharvest life. Inhibition of sprout growth to permit long-term storage and marketing of the roots is a major challenge in the sweetpotato industry. To date, no technically and economically satisfactory method is available to extend the tropical storage of sweetpotato. Previous studies have demonstrated the efficacy of both exogenous ethylene and the ethylene perception inhibitor 1-methylcyclopropene (1-MCP) in suppressing sprout growth in other root crops such as potato and onion, which display differential endodormancy. It has been proposed, through studies by others, that ethylene and 1-MCP may also enhance sweetpotato storage. In the present study, the physiological and biochemical effects of exogenously applied ethylene and 1-MCP were further investigated. Cont/d.
Open Access
Elucidating ethylene-mediated physiology and biochemistry in selected climactic and non-climacteric fruits using e+® ethylene remover
(Cranfield University, 2013-05) Elmi, Fardusa; Terry, Leon A.
The presence of ethylene in a storage environment can undermine both quality and postharvest life of many fruits, often generating significant waste and associated economic losses. A demand for discovering alternative technologies capable of scavenging ethylene has led to the development of a new material, e+® Ethylene Remover, which has significant ethylene adsorption capacity. The material has been shown to remove ethylene to below physiologically active levels during fruit storage at 0-20 o C and consequently extend postharvest life for a variety of fresh produce types. Different formats incorporating e+® Ethylene Remover have been developed. Successful application of e+® Ethylene Remover in laboratory settings has created opportunities to test new formats of the product. To this end, work was conducted herein to attest whether e+® Ethylene Remover, which has been shown to maintain avocado (Persea americana cv. Hass) firmness in recent laboratory trials, could result in a meaningful extension of storage life in a commercial setting. It was shown that e+® Ethylene Remover coated sheets were a highly efficacious format for suppressing ethylene and extending storage life of imported avocado and pluot plums in a series of commercial trials. Moreover, the potency of the e+® Ethylene Remover treatment in retarding ethylene induced ripening was significantly enhanced when avocados were treated during the early stages of ripening. After a storage period of up to 31 days (5-6 o C), avocado fruits which had received an early treatment at source and then treated again in the laboratory were significantly more firm and greener compared to fruits treated following 5 weeks of transit alone . Strawberry is regarded as non-climacteric fruit; nevertheless, exogenous ethylene can negatively influence postharvest life. The low ethylene produced by non-climacteric fruits has been generally ignored and research reporting on the involvement of ethylene in these fruits is typically devoid in the literature. To this end, application of a highly sensitive laser based photoacoustic ethylene detector has revealed a possible role of ethylene in determining the postharvest life of strawberries. Moreover, fruit quality parameters including disease incidence, sugars, organic acids, phenolic compounds and plant phytohormones/metabolites were found to be profoundly affected by ethylene and likewise the removal of ethylene. Storage of strawberries in the presence of e+® Ethylene Remover was associated with lower disease incidence, significantly less red fruits and higher ascorbic acid content. In contrast, ethylene and 1-methylcyclopropene (1-MCP) treatments resulted in the higher postharvest disease. Ethylene-treated fruits were associated with lower level of sucrose and higher simple sugars (fructose and glucose) suggesting a role of ethylene in promoting the rate of senescence and concomitant reduced postharvest quality of strawberries. Changes in ABA, ABA metabolites and auxins within different tissues of ripe strawberry during storage were investigated. ABA was more abundant in the flesh than in the achenes, while auxins were undetectable in the flesh tissue. Auxins indole-3-acetic acid (IAA) and the conjugated form indole-3-acetylaspartic acid (IAAsp) were detected in high concentrations in the achenes and were affected by ethylene and storage length.
Open Access
The first comprehensive chemical profiling of Vachellia gummifera (Willd.) Kyal. & Boatwr., a plant with medicinal value
(Wiley, 2024-03-19) Kisiriko, Musa; Noleto-Dias, Clarice; Bitchagno, Gabin T. M.; Naboulsi, Imane; Anastasiadi, Maria; Terry, Leon A.; Sobeh, Mansour; Beale, Michael H.; Ward, Jane L.
Vachellia gummifera (Willd.) Kyal. & Boatwr. is a medicinal plant endemic to Morocco that has no documented studies on its chemical composition. In this study, the chemical composition of the water/methanol (4 : 1) extracts of air-dried leaf and stem samples of Moroccan V. gummifera was determined using UHPLC-MS and NMR. In total, over 100 metabolites were identified in our study. Pinitol was the major compound in both the leaf and stem extracts, being significantly more abundant in the former. Asparagine and 3-hydroxyheteroendrin were the second most abundant compounds in the stem and leaf extracts, respectively, though both compounds were present in each tissue. The other compounds included flavonoids based on quercetin, and phenolic derivatives. Eucomic acid, only identified in the stems and was the major aromatic compound distinguishing the leaf and stem profiles. Quercetin 3-O-(6′′-O-malonyl)-β-D-glucopyranoside was identified as the major flavonoid in the leaves but was also present in the stems. Other malonylated derivatives that were all flavonol glycosides based on myricetin, kaempferol, and isorhamnetin in addition to quercetin were also identified. This is the first report of eucomic acid and malonylated compounds in Vachellia species. This report provides valuable insights into the chemotaxonomic significance of the Vachellia genus.
Open Access
Future foods: Morphological scenarios to explore changes in the UK food system with implications for food safety across the food chain
(Elsevier, 2023-03-20) Garnett, Kenisha; Delgado, Joao Pedro Correa; Lickorish, Fiona A.; Pollard, Simon J. T.; Medina-Vayá, Ángel; Magan, Naresh; Leinster, Paul; Terry, Leon A.
Scenarios are used to examine systemic change in food systems so policy makers can craft opportunities to improve the management of uncertainty and shape food policy. We present a number of alternative scenarios of the food system for 2035, developed with the Food Standards Agency, the independent government department working to protect public health and consumers’ interest in relation to food for England, Wales and Northern Ireland. To build scenarios we employed morphological analysis; a non-quantified method for modelling multiple scenario variables (food system drivers, projections), simulating their interactions and all possible scenario combinations. A cross-consistency analysis compared all possible scenario combinations to identify which set of driver projections formed a logical (internally consistent) scenario. Recently, we augmented the scenarios to consider the potential impacts and consequences of Brexit and the pandemic on consumer food safety. Outputs illustrate the consequences of extreme impacts emerging from an optimistic (Global Trading) and pessimistic (Resource Tensions) future for the food system. The scenarios establish a context for foresight in decision-making and a framework for evaluating the robustness of policies considering the opportunities and challenges arising from Brexit and a global pandemic.
Open Access
Identification of volatile organic compounds (vocs) as biomarkers of potato rots during cold storage and ecophysiological study of the pathogens involved.
(Cranfield University, 2021-03) Gutierrez-Pozo, Maria; Medina-Vayá, Ángel; Kourmpetli, Sofia; Terry, Leon A.
Potato tubers are stored for up to ten months. Therefore, controlling the conditions (temperature and relative humidity) in the storage environment is essential to reduce the risk of appearance of potato diseases. Fluctuations in the environmental conditions appear throughout the storage room, allowing the development of potato rots. This work aimed to identify Volatile Organic Compound (VOC) biomarkers of potato diseases to achieve an early identification of potato rots under commercial storage conditions. Furthermore, to achieve a deep understanding of the ecophysiology of the fungal and bacterial pathogens involved. Some of the objectives of this study were the isolation of fungal pathogens from potato tubers, the study of the mycotoxin production in the presence of dry rot, the development of a methodology for the VOC sampling and identification, and the study of the effect of storage time on the potato susceptibility to dry rot and soft rot. A method for the untargeted detection and identification of VOCs produced by potatoes during storage was developed using Thermal Desorption-Gas Chromatography-Time of Flight- Mass Spectrometry. A range of different TD (Thermal desorption) tubes were evaluated, and the most suitable for the adsorption of VOCs under the study conditions were selected. An in vitro study of the pathogens responsible for gangrene and dry rot was carried out using Natural Potato Dextrose Agar (PDA) and three different temperatures (5,10 and 15ᴼC) and water activities (aw) (0.97, 0.98, 0.99). Higher temperature and aw resulted in higher growth rate and lag time of both pathogens, Fusarium spp. and Boeremia foveata. Furthermore, mycotoxins, such as T-2, HT- 2, diacetoxyscirpenol, beauvericin and neosolaniol, were detected in potato tubers infected with dry rot. An in vivo study of dry rot and soft rot was carried out at 8.5ᴼC, using two cultivars with different susceptibility to these diseases (cvs. Record and Casablanca). The internal and external lesions resulting from the infection were assessed over time and the VOC fingerprint of each cultivar at each time point was determined. The effect of storage time on the disease severity was also evaluated, demonstrating that at 8.5ᴼC, only dry rot’s severity was affected by the longer storage time, while no effect was observed in soft rot. Several VOCs were detected in higher abundance in presence of the pathogen in the in vivo and in vitro studies. They were selected as potential biomarkers of dry rot, soft rot and gangrene. Ethanol, acetone, ethyl acetate and acetic acid were detected in vitro as potential indicators of the presence of a fungal or bacterial disease. Furthermore, 2-methylpropan-1-ol was selected as a potential indicator of the presence of a fungal pathogen, such as Fusarium spp., responsible for dry rot in potato tubers. In vivo, 1-methoxy-3-methylbutane, 2- butanone, dimethyl disulfide and hydrogen cyanide were detected as potential biomarkers of dry rot or soft rot in potato tubers. Lastly, based on the findings that have been achieved in this work, future research should be focused on the study of the growth and VOC production of Pectobacterium carotovorum spp. in vitro and the study of the disease severity and VOC production of gangrene in vivo. Furthermore, a validation of the VOC results achieved in this work under commercial storage conditions should be carried out. These studies will confirm and enhance the findings achieved in this work.
Open Access
Improving the tea withering process using ethylene or UV-C
(American Chemical Society, 2021-11-05) Collings, Emma R.; Alamar, M. Carmen; Bogaerts Márquez, Maria; Kourmpetli, Sofia; Kevei, Zoltan; Thompson, Andrew J.; Mohareb, Fady; Terry, Leon A.
Using a combination of biochemical, transcriptomic, and physiological analyses, we elucidated the mechanisms of physical and chemical withering of tea shoots subjected to UV-C and ethylene treatments. UV-C irradiation (15 kJ m–2) initiated oxidation of catechins into theaflavins, increasing theaflavin-3-monogallate and theaflavin digallate by 5- and 13.2–4.4-fold, respectively, at the end of withering. Concomitantly, a rapid change to brown/red, an increase in electrolyte leakage, and the upregulation of peroxidases (viz. Px2, Px4, and Px6) and polyphenol oxidases (PPO-1) occurred. Exogenous ethylene significantly increased the metabolic rate (40%) and moisture loss (30%) compared to control during simulated withering (12 h at 25 °C) and upregulated transcripts associated with responses to dehydration and abiotic stress, such as those in the ethylene signaling pathway (viz. EIN4-like, EIN3-FBox1, and ERFs). Incorporating ethylene during withering could shorten the tea manufacturing process, while UV-C could enhance the accumulation of flavor-related compounds.
Open Access
Influence of temperature and packaging on physiological and chemical profiles of imported litchi fruit
(Elsevier Science B.V., Amsterdam., 2011-08-01T00:00:00Z) Somboonkaew, Nettra; Terry, Leon A.
The aim of this study was to detail the physiological and biochemical changes in non-adulterated and commercially-treated litchi fruit stored in different packaging films under different storage temperatures. Litchi fruit cv. Mauritius treated with either SO2 and acid (commercially-treated fruit), or free from both SO2 and acid (non-adulterated fruit), were imported from Israel and packed using two different packaging films viz. micro-perforated polypropylene or PropaFreshTM PFAM, or stored unwrapped, at 5 or 13°C for 11days. Both CO2 and ethylene concentrations were lower in commercially-treated fruit and at storage of 5°C but higher in PropaFreshTM PFAM films. Weight loss was least in commercially-treated fruit wrapped with PropaFreshTM PFAM at 5°C. Non-adulterated fruit wrapped in PropaFreshTM PFAM had higher individual aril sugars and organic acids whilst commercially-treated fruit retained higher concentrations of anthocyanins. These results indicate that PropaFreshTM PFAM packaging at 5°C could be used to maintain postharvest quality in both commercially-treated and non-adulterated litchi fruit.
Open Access
Inhibition of the intestinal postprandial glucose transport by gallic acid and gallic acid derivatives
(Royal Society of Chemistry, 2021-05-08) Wang, Huijun; Fowler, Mark I.; Messenger, David J.; Ordaz-Ortiz, Jose Juan; Gu, Xuelan; Shi, Songshan; Terry, Leon A.; Berry, Mark J.; Lian, Guoping; Wang, Shunchun
Inhibition of glucose uptake in the intestine through sodium-dependent glucose transporter 1 (SGLT1) or glucose transporter 2 (GLUT2) may be beneficial in controlling postprandial blood glucose levels. Gallic acid and ten of its derivatives were identified in the active fractions of Terminalia chebula Retz. fructus immaturus, a popular edible plant fruit which has previously been associated with the inhibition of glucose uptake. Gallic acid derivatives (methyl gallate, ethyl gallate, pentyl gallate, 3,4,6-tri-O-galloyl-β-D-glucose, and corilagin) showed good glucose transport inhibition with inhibitory rates of 72.1 ± 1.6%, 71.5 ± 1.4%, 79.9 ± 1.2%, 44.7 ± 1.2%, and 75.0 ± 0.7% at 5 mM D-glucose and/or 56.3 ± 2.3, 52.1 ± 3.2%, 70.2 ± 1.7%, 15.6 ± 1.6%, and 37.1 ± 0.8% at 25 mM D-glucose. However, only 3,4,6-tri-O-galloyl-β-D-glucose and corilagin were confirmed GLUT2-specific inhibitors. Whilst some tea flavonoids demonstrated minimal glucose transport inhibition, their gallic acid derivatives strongly inhibited transport effect with GLUT2 specificity. This suggests that gallic acid structures are crucial for glucose transport inhibition. Plants, such as T. chebula, which contain high levels of gallic acid and its derivatives, show promise as natural functional ingredients for inclusion in foods and drinks designed to control postprandial glucose levels.
Open Access
An integrated approach to control and manage potato black dot disease: a review
(Springer, 2023-09-15) Sanzo-Miró, Marta; Simms, Daniel M.; Rezwan, Faisal I.; Terry, Leon A.; Alamar, M. Carmen
Potato black dot is a foliar and tuber blemish disease that has become an increasingly economic problem in recent years. Black dot is caused by the fungus Colletotrichum coccodes and is characterised by silver/brown lesions on the tuber skin leading to lower aesthetic quality of potatoes destined for the pre-pack market. Given the consumers’ growing demand for washed and pre-packed potatoes, skin blemish diseases (such as black dot and silver scurf), once considered of minor importance, are now serious challenges for the fresh potato industry. The management of C. coccodes is far from satisfactory at either pre- or postharvest stages: firstly, the disease symptoms have not been consistently described on potato plant foliage; and secondly, black dot disease is often confounded with other tuber blemishes during postharvest storage. Good field managing practices in combination with improved postharvest strategies and an accurate detection support tool can be a useful integrated approach to manage potato black dot disease. This review aims to evaluate and critically discuss different novel approaches for better management and detection of potato black dot disease.