Lab
George Manganaris's Lab
Institution: Cyprus University of Technology
About the lab
CUT Fruit Sciences/Postharvest Group (www.fruitsciences.eu) is part of the Department of Agricultural Sciences, Biotechnology and Food Science (ABF) at the Cyprus University of Technology (CUT), based in Lemesos, Cyprus. Our group has extensive research experience in issues related to postharvest physiology and technology of fresh produce. Particular attention is given in the elucidation of fruit development, on-tree maturation and postharvest ripening with emphasis in the development of physiological disorders and their responsiveness to chilling temperatures.The Group set up and routinely run an array of assays related to qualitative, physicochemical, phytochemical and biochemical properties of fresh produce.
Featured research (6)
Peach is the most important temperate fruit crop worldwide in terms of production after apple. However, a descending trend has been registered over the recent years in several key producing peach countries, mainly due to the increased labor cost and the reduced revenue for the farmer. The present perspective review aims to shed light on the current trends on peach fruit production related to cultivar and rootstock breeding initiatives, appropriate training system selection and targeted integrated management of main diseases, most promptly Monilinia spp. Cultivar breeding programs should focus on the most relevant outcomes about the main drivers of consumer's acceptance. In the near future, a contribution from the breeding sector should be expected in the reduction of the trade-off between quality and yield, towards selection of elite cultivars with enhanced aroma (a pool of compounds still scarcely known), with appreciable nutritional properties and extended market life. Such cultivars need an appropriate rootstock and canopy architecture to facilitate efficient cropping systems. The training/cropping system selection is of equal importance with rootstock selection as it can also determine efficiency and potential for mechanization. A tendency for the future is that several semi- and dwarfing Prunus hybrid rootstocks aligned with the innovations on peach tree architecture will lead to higher planting densities, reduced tree height and thus enhanced peach production with reduced labor cost. With the aim to advance peach fruit production and consumption, there is an urgent need to dissect solutions to valorize on the market the exceptional peach diversity and flavor potential, already present in the varietal landscape. The development of sophisticated non-destructive tools that will allow in cost-effective manner to determine fruit quality and maturity stage is expected to facilitate consumer eating experience and storage requirements with minimum risk of chilling injury symptoms development. Lastly, the phytosanitary protocol of small-sized wall-grown plants would most likely be more effective and would require reduced quantities of pesticides while simultaneously responding to the needs of a market that is increasingly attentive to fruit healthiness and environment protection. Phytosanitary issues can be addressed by controlling diseases and/or by improving genetic resistance.
Peach (Prunus persica (L.) Batsch) is widely consumed both fresh and processed. Scarce information exists regarding the fate of phytochemicals after the peach canning process. The aim of the current study was to evaluate the compositional variability and impact of processing on the bioactive compounds profile of eight non-melting peach cultivars, both in fresh and canned forms, thermally processed with either light syrup (LS) or grape juice (GJ) as the packing medium. LC–MS analysis demonstrated that the phytochemical profile is primarily genotype dependent. Prediction profile statistics revealed that cv. ‘Andross’, a predominant clingstone peach cultivar, possessed the highest desirability score among all the examined cultivars. Free zeaxanthin and lutein remained relatively unaffected by the canning process compared to free β-carotene, whereas soluble phenolic compounds, such as neochlorogenic acid, chlorogenic acid, procyanidin B1 and catechin, showed a large decrease following canning. Using GJ, an additional source of polyphenols, as packing medium led to a reduction of losses for the bioactive compounds. Overall, the experimental findings demonstrated that, besides the thermal degradation of some sensitive to heating compounds, there is a bidirectional flow of the bioactive compounds between the fruit tissue and the liquid matrix, as balanced out by diffusion processes.
Peach (Prunus persica) fruit is widely consumed, both as fresh or as processed (mostly by canning) product. Despite its economic importance, a limited number of studies have dealt with quality assessment of clingstone peach cultivars after thermal processing. Thus, the aim of the current study was to evaluate the effect of canning process on compositional, sensorial and textural attributes of fruit from seven non-melting peach cultivars which exhibit on-tree ripening in succession, spanning from July till mid-September in the northern hemisphere. Descriptive quantitative analysis indicated discrete varietal differences, providing useful insights for the industry regarding the quality and marketing potential for canned products of each cultivar. Fruit packed in diluted-clarified grape juice concentrate, aiming towards a less caloric content product, demonstrated an inferior consumer perception regarding bitterness, astringency and off-taste. Storage of the canned fruit (6 versus 24 months) led to texture depletion modifications on a cultivar-dependent manner. ‘Ferlate®’ registered desirable textural properties, while ‘Mirel®’, besides the appealing orange-coloured fruit pieces, aligned with satisfactory sensorial properties, provide further marketing options for the peach canning industry. Both early (‘Romea’) and late-season ripening (‘VLG’) cultivars were proven amenable to canning with acceptable quality attributes, offering a sustainable solution towards extension of the non-melting peach harvesting season.
Peach (Prunus persica) products are destined for fresh consumption or are being consumed after processing in various forms. Despite its huge economic importance, no standardized protocols to define sensorial attributes and mechanical properties of canned peaches exist. Thus, the aim of the current study was dual and included the
setting up of a list of sensorial descriptors and the elaboration of a toolkit to evaluate the textural properties of canned peaches using large deformation mechanical testing. A standardized vocabulary (“consensus language”) was initially developed toward
the determination and quantification of 15 sensorial attributes through a descriptive quantitative analysis (QDA) approach. Textural properties were additionally evaluated with a TA-XT Plus texture analyzer by applying three discrete large deformation tests [(a) puncture test with a flat cylindrical probe; (b) texture profile analysis (TPA) with a
flat compression plunger; and (c) Kramer shear test (KST) cell with a bladed fixture]; that is, a total of nine textural properties, namely, “puncture firmness” (individual halves), “Kramer” hardness (applied in a complex mixture of peach slices), “TPA” hardness (central section of halves), fracturability, consistency, cohesiveness, springiness,
chewiness, and total hardness were assessed. We hereby present novel protocols that encompass the comprehensive determination of sensorial and textural properties. The established protocols, providing complementary information, are readily applicable to the canning industry in setting up qualitative tests to determine product shelf life as well as to assist on going breeding programs for the evaluation of new candidate clingstone cultivars destined for canning purposes.
Loquat marketability is affected by purple spot (PS), a preharvest physiological disorder, evident as skin discoloration with depressed surface. The intensity and severity of PS in three loquat cultivars ('Morphitiki', 'Karantoki' and 'Obusa') was phenotypically monitored during successive on-tree fruit developmental stages. At harvest. 'Obusa' fruits showed the highest incidence of purple spot (58.6%), Karantoki' fruits demonstrated an intermediate response (31.3%), while 'Morphitiki' fruits did not show any symptoms. Thereafter, fruits with 30-50% PS severity were selected and used for further analysis; peel
tissue was removed from both symptomatic and asymptomatic tissue of the same fruit for all examined cultivars. 'Karantoki' fruit with PS were characterized by the highest accumulation of total soluble sugars, sucrose, glucose and fructose contents, while the concentration of these primary metabolites was the lowest in asymptomatic fruit of 'Obusa', exception made for the sucrose. The incidence of PS was also transcriptionally investigated by assessing the mRNA profile of important genes involved in polyphenolic and carbohydrate pathway. The enhanced expression levels of CWI3 and VI genes in symptomatic 'Obusa' fruit highlight a cultivar-specific type of response. SuSy registered the lowest expression levels is symptomatic tissue of both 'Obusa' and 'Karantoki'. To what extent PPO is linked with PS incidence and whether the etiology of the disorder can be assigned to an oxidative process triggered and coordinated by its action need to be further elucidated. The aforementioned genes are suggested to be further examined as
potential markers of purple spot detection in loquat fruit.
Lab head
Department
- Department of Agricultural Sciences, Biotechnology and Food Science
About George Manganaris
- George Manganaris is Leader of Fruit Sciences & Postharvest Group (www.fruitsciences.eu) at Cyprus University of Technology, Department of Agricultural Sciences, Biotechnology & Food Science. His scientific interests includes the quality evaluation of fleshy fruits with the use of physiological, biochemical and molecular approaches, the elucidation of fruit ripening syndrome with emphasis in the development of physiological disorders and overall the postharvest maintenance of fresh produce.