Academic literature on the topic 'Persimmon fruit'

The study carried out at the Faculty of Agriculture and Life Sciences of the University of Maribor aimed to evaluate the attractiveness of dried persimmon fruit depending on the method of preparing the fruit for drying. The methods varied in terms of the ripeness of the fruit, the thickness and shape of the slices, the presence of seeds (in fertilised fruits) and the presence of peel. Sensory evaluation was performed by students and staff, using a hedonic scale, where evaluators evaluated the appearance (shape and colour) and taste (sugar-acid ratio, texture, tartness, presence of fruit peel, and general impression) of the fruit. Dried unfertilized persimmons, with the presence of peel, cut into 3 mm thick slices, were given the highest score for overall attractiveness. In terms of taste, unfertilised, peeled persimmon slices scored the highest. Considering all parameters, the results showed that unfertilised persimmons were more suitable for drying and that the presence of the peel was not a disturbing factor for consumers.

We are studying β-galactosidase (EC 3.2.1.23) in softening persimmon fruit (Diospyros kaki L.f. cv Fuyu) and hope to decrease the rate of softening by inserting an antisense construct of the β-galactosidase gene. The N-terminal amino acid sequence of persimmon fruit β-galactosidase was recently reported. Here we report the cloning of a putative β-galactosidase gene from persimmons. Degenerate oligonucleotide primers were synthesized based on the amino acid sequence. 5′-RACE (rapid amplification of cDNA ends) was done using persimmon Poly A+ mRNA extracted using a phenol: chloroform/LiCl method. Purification was done on an oligo dT-cellulose column. A fragment of roughly 150 base pairs was purified by agarose gel electrophoresis and subcloned into the pCR-Script cloning vector from Stratagene. After sequencing and verifying the insert's identity, it will be isolated and used to screen a persimmon fruit cDNA library currently being constructed. Ultimately this cDNA clone will be used to make an antisense β-galactosidase construct that will be transformed into persimmon.

The American persimmon (Diospyros virginiana) is a slow-growing, moderately sized tree fruit native to the forests of Kentucky. This tree fruit is in the early stages of commercial production with many cultivars selected from the wild. Small orchards of commercially available cultivars are planted in Kentucky. Persimmons are normally dioecious, and female trees require cross-pollination to produce fruit. There are two races of persimmon: the tetraploid (60-chromosome) race is centered in the southern Appalachian region, while the hexaploid (90-chromosome) race generally occupies a range north and west of the tetraploid range. These ranges overlap in Kentucky. Because the ranges overlap, cross-pollination may cause sexual incompatibility, resulting in pollination without fertilization, and therefore seedless fruits of poor quality. The objective of this study was to assess the ploidy level of commercially available American persimmon cultivars and native Kentucky persimmon populations. Leaf samples were collected from 45 cultivars and advanced selections, as well as 45 trees from native populations in Bullitt, Barren, and Franklin Counties. Flow cytometer analysis showed that only four of the selected cultivars were from the tetraploid race: Ennis Seedless, Weeping, Sugar Bear, and SFES; the remaining cultivars were from the hexaploid race. Both hexaploid and tetraploid American persimmon trees were identified in the populations sampled in the Bullitt County locations, but only tetraploid races were found in Franklin and Barren Counties. Because pollen from native trees could result in seedless fruit formation of poor quality when native seedlings are used as pollinizers in commercial production of American persimmon, ploidy level of seedlings needs to be considered.

In subtropical to temperate regions, persimmon (Diospyros kaki Thunb.) is an economically important fruit crop cultivated for its edible fruits. Persimmons are distributed abundantly and widely in Zhejiang Province, representing a valuable resource for the breeding of new cultivars and studying the origin and evolution of persimmon. In this study, we elucidated the genetic structures and diversity patterns of 179 persimmon germplasms from 16 different ecologic populations in Zhejiang Province based on the analysis of 17 SSR markers. The results show that there was a medium degree of genetic diversity for persimmon found in Zhejiang Province. With the exception of the Tiantai Mountain and Xin’an River populations, we found extensive gene exchange had occurred among the other populations. The 179 D. kaki germplasms from the 16 populations could be separated into three distinct clusters (I, II, and III) with a higher mean pairwise genetic differentiation index (FST) (0.2714). Nearly all samples of Cluster-I were distributed inland. Cluster-II and Cluster-III contained samples that were widely distributed throughout Zhejiang Province including all samples from the coastal populations and the Northeast Plain populations. In addition, we performed association mapping with nine traits (fruit crude fiber content, fruit calcium content, fruit water content, fruit longitudinal diameter, fruit aspect ratio, seed width, seed length, leaf aspect ratio, and number of lateral veins) using these markers. This led to the identification of 13 significant marker–trait associations (MTAs; p < 0.00044, 0.1/228) using a general linear model, of which, six MTAs with a correlation coefficient (R2) >10% were consistently represented in the general linear model with p < 0.00044 in the two models. The genetic structures and diversity patterns of the persimmon germplasms revealed in this study will provide a reference for the efficient conservation and further utilization of persimmon germplasms. The MTAs identified in this study will be useful for future marker-assisted breeding of persimmon.

As Korea is located 33-38° latitude in north hemisphere, her capacity availing deciduous fruit growing is enough in allowing successful production of persimmon, oriental pear, jujube and dwarf apple. There are two kind of persimmons, sweet and astringent, and the majority of persimmon production is the sweet one owing to the higher price and consumer preferences. Astringent persimmons are dried after peeling and served as a traditional, popular fruit punch in Korea. The most popular oriental pear cultivar in Korea is Shinko (`Niitaka'), occupying 38% of the total pear growing area. This cultivar is extending its popularity in world trade with 4,361 tons of fruits exported to Taiwan, Singapore, USA, Netherlands, etc. The future of oriental pear is quite promising along with the increasing acknowledgement of its crispness among westerners as well as oriental people living abroad. Production status of jujube and dwarf apple, mostly `Fuji' and `Tsugaru' on M.26 rootstock, will be presented with describing merits and problems of their production.

The Mexican fruit fly infests many tropical and subtropical fruits, consequently fruits must be treated for quarantine security. Although chemical fumigations are the most common quarantine treatments, interest in using cold and heat treatments has increased due to concerns over environment and human health. Recently, shorter heat treatments such as those provided with radio frequency (RF) energy have been studied on walnuts and various fresh fruits as a possible quarantine treatment. Preliminary studies with a heating block system showed that reaching temperatures of 50 °C with a holding period of 2 min. or 48 °C for 6 minutes was required to achieve 100% insect mortality of 600 third instar Mexican fruit flies (the most heat resistant insect stage). Doubling the holding time required to achieve 100% insect mortality would likely be necessary to provide for Probit 9 security. Fresh fruits such as persimmons and guavas are commonly infested by the Mexican fruit fly. Persimmon and guava fruit were treated with RF energy to temperatures ranging from 48 to 52 °C at different holding periods. After treatments fruit were evaluated for external appearance, decay, soluble solids, titratable acidity, internal flesh quality, and ethylene production and respiration rate. Persimmon fruit tolerated the lower temperature, 48 °C for up to 18 min., but temperatures above 50 °C for more than 1 minute caused internal damage. Preliminary studies with guava indicate that fruit may tolerate 50 °C, but fruit quality after storage is still to be evaluated.

Irradiation is becoming a more accepted phytosanitary market access treatment for some international horticultural trades. However, there is little information on the effects of phytosanitary irradiation treatment on persimmon fruit quality. ‘Jiro’ persimmon fruit were treated with an average of 769 Gray (Gy) at a commercial phytosanitary irradiation X-ray facility to examine the effect of this market access treatment on fruit quality during storage. After treatment, fruit were stored in air at 15 °C for up to three weeks. The results showed that, in general, there was no effect of irradiation treatment on fruit weight loss, calyx appearance, fruit firmness (objective and subjective), total soluble solids (TSS), titratable acidity (TA), internal appearance, and ethylene production rate. There were some treatment differences in fruit respiration rates and some aspects of fruit appearance and colour, where irradiated fruit had higher respiration rates and were slightly darker with higher levels of skin blemish, although these measured differences were not commercially significant. This study showed the promise of using low dose irradiation as a phytosanitary treatment for ‘Jiro’ persimmons, but more work is required to test other persimmon cultivars and other storage and marketing environments.

The external and internal quality of ‘Fuyu’ persimmon fruit (Diospyros kaki L.) was evaluated after heating with radiofrequency (RF) energy to 48, 50, or 52 °C, holding at the target temperatures for durations ranging from 0.5 to 18 minutes, hydrocooling, and ripening at 20 °C for 12 days. These treatment conditions were identified for control of third instar Mexican fruit fly larvae (Anastrepha ludens). The treatments had no commercially significant effect on firmness, soluble solids content, titratable acidity, or weight loss of the fruit. RF-treated persimmon fruit attained a deeper orange–red skin color than control fruit. There was a greater incidence of slight to moderate flesh browning in fruit heated to 50 and 52 °C as compared with 48 °C. Calyx browning increased slightly in all RF-treated fruit and was the highest in the longer treatments at each temperature. Heating persimmon fruit with RF to 48 °C and then holding for 6 or 12 minutes showed the least damage, and the latter treatment was longer than should be required for a quarantine treatment against the third instar Mexican fruit fly. Holding persimmons for 6.6 minutes at 48 °C should provide control of the Mexican fruit fly and maintain fruit quality. Confirmation tests with infested fruit should be conducted.

‘Mopan’ persimmon (Diospyros kaki Thunb.) is a traditional astringent cultivar of persimmon and ‘Yoho’ persimmon (D. kaki) is a newly introduced Japanese nonastringent type of cultivar in northern China. Studies were conducted to investigate the physiological changes and expression of ripening-related genes in the postharvest process at different periods under the effects of endogenous ethylene in both cultivars. Persimmons were harvested and stored under room temperature for 20 days. An analysis of physiological changes showed significant differences between the two cultivars. Total soluble solids declined in ‘Mopan’ fruit, whereas those in ‘Yoho’ fruit increased during storage. Firmness, color, index of absorbance difference, total and soluble tannin contents, ethylene production, and respiration rates showed the same trend, but these values vary by cultivar. ‘Mopan’ fruit softened rapidly after harvest and attained edible quality in 20 days, with an increased rate of softening accompanied by increased expression of ripening-related genes. In contract, ‘Yoho’ fruit softening occurred slowly and did not soften even after 20 days, with minimal accumulation of the ripening-related genes. The information obtained from this study demonstrates that cell wall-hydrolyzing enzymes, the de-astringent process, and endogenous ethylene have critical roles in postharvest ripening, gene expression, and physiological property changes of ‘Mopan’ and ‘Yoho’ persimmon fruit during storage.

Potential sources of microbial contamination for persimmon fruit during growing and harvesting in the 2005 season were investigated to provide a baseline to design the good agricultural practices program for persimmons in Japan. Microbial counts in the peel of persimmon fruit during production season were close to or below 2.4 log CFU/g for bacteria and 3.0 log CFU/g for fungi but were above these values on harvested fruit. The counts in the flesh were below the detection level with all fruit. Bacteria and molds isolated from peel and flesh of persimmons during growing were phytopathogenic and soilborne organisms such as bacteria genera Enterobacter and Bacillus and mold genera Fusarium and Cladosporium, which were found in soil, weeds, agricultural water, and pesticide solution throughout the production season. The agricultural water was one of the most important potential preharvest sources, because Escherichia coli O157:H7 was identified from agricultural water in May, and Salmonella was detected in agricultural water, pesticide solution containing the agricultural water for the mixture, and soil after application of the pesticide solution in June. Neither of the two pathogenic bacteria was detected in any of the fruit samples. Microbial counts and diversity in the peel of persimmons at harvest increased after contact with plastic harvest basket and container, which could be sources of contamination during harvesting. Therefore, monitoring and management on-farm should focus on agricultural water and harvest equipment as important control points to reduce microbial contamination on persimmons.

Thesis (MScAgric (Horticulture))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: Persimmon production is new to South Africa with about 700 ha planted to the dioecious, parthenocarpic Triumph cultivar since 1998. Little local expertise is available to assist growers in achieving high yields of high quality fruit and previous research has shown that recipes that are followed in Israel, from where ‘Triumph’ was introduced to South Africa, do not necessarily have any beneficial effect in South Africa. ‘Triumph’ orchards in South Africa are often late in reaching full production. Persimmon trees are generally vigorous and prone to excessive fruit drop, partly due to excessive vegetative growth, especially when young and grown on the very vigorous Diospyros lotus seedling rootstock. The first objective of this study was to evaluate the use of growth retardants and various severities of girdling to increase flower formation, fruit set and yield in vigorous, young ‘Triumph’ orchards. Scoring and girdling improved fruit set and yield in two such orchards and are recommended as tools to improve yield in ‘Triumph’ in South Africa. Strapping, prohexadione-Ca (P-Ca) and paclobutrazol (PBZ) did not increase yield whereas 5 mm bark removal was too severe a treatment and decreased fruit quality in the current season and yield in the following season. None of the treatments had an effect on flower formation or decreased vegetative growth. PBZ, especially as foliar spray, appears to advance fruit maturity. P-Ca at 125 mg L-1 and 250 mg L-1 induced phytotoxicity symptoms and decreased yields in both orchards. However, further research is required before P-Ca and PBZ are completely discarded as treatments to manage vigor in ‘Triumph’ persimmon in South Africa. In contrast to the negative effect of excessive vigor on fruit production, the profitability of orchards is dependent on the rapid growth of trees after planting in order to fill the allotted canopy volume and achieve full production as quickly as possible. Hence, the second objective of this study was to determine optimum levels of irrigation and fertilizer application rates to attain early, high yields in newly planted ‘Triumph’. Fertigation was applied at three levels, viz. ½X, 1X and 2X with 1X being the commercial standard application rate. Irrigation was also applied at these levels without addition of fertilizer. In addition, fertilizer was applied at 0X, ½X and 1X at 1X irrigation level. Tree size increased with an increase in water application rate. Yield also increased linearly with an increase in water application rate due to a linear increase in fruit size. Fertigation and ½X water as well as an increase in fertilizer application rate at 1X irrigation substantially delayed fruit ripening. Hence, careful management of fertilizer and water application rate could be used to extend the harvesting period and, therefore, the marketing window of South African ‘Triumph’. We recommend that the trial be continued for a further few seasons so that the effect of water and fertilizer application rates on fruit quality and storability can be assessed. Fruit set may also be affected as trees reach their mature size with a concomitant increase in shading.
AFRIKAANSE OPSOMMING: Persimmonverbouing is ‘n nuwe bedryf in Suid-Afrika met ongeveer 700 ha van die tweeslagtige, partenokarpiese Triumph cultivar wat sedert 1998 aangeplant is. Min plaaslike kundigheid is beskikbaar om produsente van raad te bedien oor hoe om te werk te gaan om hoë opbrengste van hoë kwaliteit te verkry. Vorige navorsing het getoon dat resepte wat ‘Triumph’ van Israel na Suid-Afrika gevolg het, nie noodwendig suksesvol hier toegepas kan word nie. ‘Triumph’ boorde in Suid-Afrika neig om lank te neem alvorens hul hul maksimum produksievermoë bereik. Persimmons is oor die algemeen baie groeikragtig en geneig tot hoë vrugval, deels as gevolg van hul geil groei, en veral terwyl hulle jonk is en op die uiters groeikragtige Diospyros lotus saailingonderstam geënt is. Die eerste doelwit van hierdie studie was om die invloed van groei inhibeerders en verskillende grade van strafheid van ringelering op blomvorming, vrugset en oesopbrengs in jonk, sterk-groeiende ‘Triumph’ boorde te evalueer. Insnyding en ringelering met ‘n handsaag het vrugset en oeslading in twee groeikragtige boorde verbeter en word aanbeveel as geskikte ingrepe om die oeslading van ‘Triumph’ te verhoog. Draad-ringelering, en aanwending van prohexadione-Ca (P-Ca) en paclobutrazol (PBZ) het nie die opbrengs verhoog nie terwyl die verwydering van `n 5 mm strook bas té aggresief was en die vrugkwaliteit in die seisoen van toediening en opbrengs in die daaropvolgende seisoen verlaag het. Geen van die behandelings het blomvorming geaffekteer of vegetatiewe groei verminder nie. Dit wil voorkom asof PBZ, veral as blaartoediening, vrugrypwording kan versnel. Blare het tekens van fitotoksisiteit getoon na aanwending van P-Ca teen 125 mg L-1 en 250 mg L-1. P-Ca het ook die opbrengs in beide boorde aansienlik verlaag. Verdere navorsing is egter nodig alvorens P-Ca en PBZ sondermeer verwerp word as behandelings om die groei van ‘Triumph’ te beheer. Die winsgewendheid van boorde is afhanklik daarvan dat bome aanvanklik vinnig groei ten einde die toegekende boomryvolume so spoedig moontlik te vul en sodoende so vinnig as moontlik hul vol produksievermoë bereik. Bogenoemde is natuurlik teenstrydig met die negatiewe effek van uitermatige geil vegetatiewe groei op vrugproduksie. Die tweede doelwit van hierdie studie was dus om die optimale vlakke van besproeiing en bemesting te bepaal wat die vroeë aanvang van hoë opbrengste in nuwe ‘Triumph’ boorde sal verseker. Vloeibare bemesting is in kombinasie met besproeiing teen drie vlakke toegedien nl. ½X, 1X en 2X met 1X die kommersiële standaard vlak van toediening. Besproeiing is ook teen hierdie vlakke toegedien sonder dat kunsmis bygevoeg is. Addisioneel hiertoe is bemesting ook toegedien teen ½X, 1X en 2X teen 1X besproeiing. Boomgrootte het toegeneem met `n toename in die vlak van besproeiing. `n Lineêre toename in vruggrootte met ‘n toename in die vlak van besproeiing het ‘n oorsaaklike lineêre toename in opbrengs tot gevolg gehad. Bemesting in kombinasie met besproeiing, ½X besproeiing sonder bemesting, asook `n toename in die bemestingsvlak by 1X besproeiing het vrugrypwording substansieel vertraag. Die omsigtige bestuur van bemesting- en besproeiingsvlakke kan moontlik gebruik word om die oesperiode, en dus die bemarkingsvenster, vir Suid-Afrikaanse ‘Triumph’ te verleng. Ons beveel aan dat die proef vir ‘n vêrdere aantal seisoene voortgesit word sodat die effek van bemesting- en besproeiingsvlakke op vrugkwaliteit en -houvermoë bepaal kan word. Verhoogde oorskaduwing soos wat bome van sekere behandelings hul toegekende spasie bereik en oorskry, kan ook in die toekoms ‘n invloed op vrugset uitoefen.

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第16121号
農博第1857号
新制||農||988(附属図書館)
学位論文||H23||N4591(農学部図書室)
28700
京都大学大学院農学研究科農学専攻
(主査)教授 米森 敬三, 教授 土井 元章, 教授 奥本 裕
学位規則第4条第1項該当

Thesis (MScAgric)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: Production of the South African ‘Triumph’ persimmon grown as a counter season supply to European markets declined from 740 ha in 2008 to 550 ha in 2011 due to, among other factors, quality variation observed when the fruit arrives at the market. Variation in fruit quality affects acceptability, hence profitability. The aim of this study was to investigate the effects of time of maturity (influenced by region and paclobutrazol treatment), stage of maturity at harvest (colour), orchard differences and wind on ‘Triumph’ persimmon storage potential (6.5 weeks at -0.5 oC and after 4 days shelf-life at 20 oC) as well as evaluation of near-infrared spectroscopy (NIRs) as an objective tool to sort fruit of various maturity stages. The first study compared storage potential of fruit from an early region treated with paclobutrazol, an untreated early region and a late region harvested at 4 stages of maturity determined by the Perishable Product and Inspection Services (PPIS) persimmon colour chart. Harvesting South African ‘Triumph’ persimmon at colour group 3 (PPIS colour chart values 5-6 compared to commercial harvest at 4-5) demonstrated the potential to improve fruit storage potential regardless of the maturity time. The second trial compared storage potential of fruit harvested at colour group 3 from 4 orchards on each maturity time in the 2012 season and 5 orchards on adjacent farms in the 2013 season. The results demonstrated that, although harvesting fruit at PPIS colour chart values 5-6 improved the general post-harvest quality, significant quality variation resulting from orchard factors could occur. The third trial investigated the effect of wind on storage potential of ‘Triumph’ persimmon fruit by simulating wind and wind damage by blowing trees for 10 min, shaking trees for 2 min, defoliating half of the trees and twisting fruit stalks. Wind simulations increased soft fruit after cold storage, decreased titratable acidity (TA) and total soluble solids (TSS) after shelf-life and delayed fruit colour development after storage and after shelf-life. The effect of wind simulation and simulated damage on storage potential varied per season and should be studied further in more detail. However, orchard practices that reduce wind power may improve quality of stored ‘Triumph’ persimmon fruit. The fourth trial investigated the possibility of using near infra-red spectroscopy (NIRs) as an alternative or complimentary non-destructive fruit sorting tool. Near infra-red (NIR) spectra were obtained over the wavelength range of 800-2500 nm. Flesh firmness, Sinclair (IQ) firmness, TSS, TA and fruit colour were determined using conventional methods after spectral measurements. All measured quality parameters showed that PPIS colour chart alone may not categorise fruits into precise distinctive maturity stages. NIR calibration and validation models proved that NIRs predicts TSS and fruit colour throughout post-harvest storage of ‘Triumph’ persimmon fruit. In conclusion, this study found that harvesting South African ‘Triumph’ persimmon at PPIS colour chart values 5-6, orchard management for post-harvest quality, reducing wind damage and using NIRs as complimentary maturity indexing tool may improve storage potential of the South African ‘Triumph’ persimmon fruit.
AFRIKKANSE OPSOMMING: Die produksie van Suid-Afrikaanse ‘Triumph’ persimmons om die Europese markte te voorsien gedurende die tyd van die jaar wanneer daar geen vrugte op die mark is nie, het afgeneem vanaf 740 ha in 2008 tot 550 ha in 2011. Een van die faktore wat ‘n rol gespeel het in die afname van produksie is die variërende kwaliteit van vrugte op die mark. Vrugkwaliteit variasie affekteer die bemarkbaarheid van vrugte, en dus winsgewendheid. Die doel van die studie was om die effek van tyd van oesrypheid (soos bepaal deur kleur en beïnvloed deur produksie area en paclobutrazol behandeling), boordvariasie en wind op ‘Triumph’ persimmon opberging (6 weke en 3 dae by -0.5 oC) en rakleeftyd (4 dae by 20 oC) te bepaal. Die studie het ook die geskiktheid van naby-infrarooi spektroskopie (NIRs) as ‘n objektiewe sorteringsinstrument van verskeie rypheidsstadia getoets. Die eerste proef vergelyk opbergingspotensiaal van vrugte uit ‘n vroeë produksie area behandel met paclobutrazol, onbehandelde vrugte uit ‘n vroeë produksie area, en vrugte uit ‘n laat produksie area geoes by 4 verskillende stadia van rypwording soos bepaal deur die Bederfbare Produkte en Inspeksie Dienste (Perishable Product and Inspection Services (PPIS)) se persimmonkleurkaart. Die oes van Suid-Afrikaanse persimmons by kleurkaartgroep 3 (PPIS kleurkaart waardes 5-6 in vergelyking met kommersiële oes by 4-5) het die potensiaal om vrugopbergbaarheid te verbeter onafhanklik van produksie area. Die tweede proef vergelyk opbergbaarheid van vrugte van 4 boorde in elke rypwordings tyd / area (2012 seisoen) en 5 boorde op aangrensende plase (2013 seisoen) wat by kleurgroep 3 geoes is. Die resultate demonstreer dat alhoewel vrugkwaliteit na-oes beter behou word wanneer vrugte by PPIS kleurkaartwaardes van 5-6 ge-oes word, betekenisvolle kwaliteitsvariasie bestaan as gevolg van boordverskille. Die derde proef ondersoek die effek van gesimuleerde wind en windskade op die opbergbaarheid van ‘Triumph’ persimmonvrugte. Dit is gedoen deur bome vir 10 min te blaas met lug met behulp van ‘n kommersiële boordspuitpomp, hard te skud vir 2 min, deur die helfte van die blare te stroop, en deur die vrugstele te wring. Windsimulering verhoog die persentasie sagte vrugte na koueopberging, verminder titreerbare sure (TS) en totale oplosbare vastestowwe (TOVS) na rakleeftyd en vertraag vrugkleurontwikkeling na opberging en rakleeftyd. Die effek van windsimulering en geassosieerde skade op opbergbaarheid het baie gevarieer tussen seisoene en moet verder en in meer detail bestudeer word. Boordpraktyke wat windkrag verminder mag egter ‘n verbetering in die kwaliteit van ‘Triumph’ persimmonvrugte tot gevolg hê. Die vierde proef bestudeer die geskiktheid van NIRs as ‘n alternatiewe of aanvullende niedestruktiewe vrugsorteringsapparaat. NIR spektra is ingesamel tussen 800-2500 nm. Fermheid, Sinclair (IQ) fermheid, TOVS, TA en vrugkleur is bepaal deur konvensionele metodes na spektrale metings. Alle vrugkwaliteitsparameters het gewys dat die PPIS kleurkaart nie alleen die vrugte in presiese rypheidsklasse kan indeel nie. NIR kalibrasie en validasie modelle bewys dat NIRs TOVS en vrugkleur ‘Triumph’ persimmon na-oes kwaliteit kan voorspel. In gevolgtrekking het die studie bevind dat die oes van Suid-Afrikaanse persimmonvrugte by PPIS kleurkaartwaardes van 5-6, boordbestuurspraktyke vir die behoud van na-oes kwaliteit, windskade vermindering en die gebruik van NIRs as ‘n aanvullende rypheidsindekseringsapparaat die opbergingsvermoë van Suid Afrikaanse ‘Triumph’ persimmons mag verbeter.

Revised; Originally Published: 2000
7 pp.
The mid elevations (3,500 to 6,000 feet) in Arizona can be ideal for growing tree fruit. Site selection can make a pronounced effect on how well fruit will grow and produce. The warmer the site the greater the chance of success. Areas where cold air settles are a poor choice for tree fruit production. Variety selection is very important for good fruit production.February and March are the best months to plant bare root trees, although they can be planted anytime during the dormant season. Try to plant 30 days before bud break. Containerized plants are best planted in late September through early October. The open center pruning system allows for more sunlight to reach all the branches of the tree. Whereas the central leader is used with those trees that are less vigorous. Training trees when young is an important step in ensuring a strong scaffold system when bearing. Fruit thinning helps to control fruit size and consistent bearing. Proper fertilization, irrigation, and pest control will promote healthy productive trees.

O Brasil é um dos três maiores produtores mundiais de frutas, com uma produção que supera os 39 milhões de toneladas, com grande participação no mercado externo e crescente participação no mercado interno. Entretanto, não basta apenas ter quantidade, a qualidade e inocuidade do alimento são quesitos cada vez mais exigidos pelos consumidores. Tem-se conhecimento que produtos in natura podem apresentar contaminantes microbiológicos e a refrigeração é tipicamente utilizada para retardar o desenvolvimento microbiano nos produtos frescos. Microrganismos psicrotróficos, como Listeria monocytogenes, são capazes de se desenvolverem sob refrigeração. Esta bactéria é um importante patógeno causador de doenças transmitidas por alimentos e, devido a gravidade da doença e a elevada taxa de mortalidade em indivíduos suscetíveis, vem merecendo a atenção de microbiologistas de alimentos e profissionais da área da saúde. Nas frutas de baixa acidez, dentre as quais está o caqui (Diospyros kaki), L. monocytogenes pode ainda ter condições para sobreviver e se multiplicar, pois esta fruta não é submetida a tratamentos fitossanitários pós-colheita. Em muitos países, incluindo o Brasil, o caqui é consumido com a casca, logo, uma provável contaminação externa torna a situação ainda mais crítica com relação a inocuidade do produto. Assim sendo, este estudo teve como objetivos: (1) verificar a incidência de L. monocytogenes na casca de caquis (Diospyros kaki) \'Fuyu\' e \'Rama Forte\'; (2) estudar a sobrevivência e multiplicação daquele patógeno na casca e na polpa dessa fruta em diferentes tempos e temperaturas de incubação; (3) e obter parâmetros de crescimento (a duração da fase lag, o tempo de geração e a taxa de crescimento exponencial). A pesquisa de incidência de L. monocytogenes na superfície dos caquis foi realizada durante os meses de março a julho nos anos de 2005 e 2006. As amostras foram coletadas no comércio varejista na região de Campinas, interior do Estado de São Paulo, e no atacado, sendo o CEAGESP o local escolhido para esse último tipo de coleta. Um total de 582 frutos foram analisados pelo sistema Bax®, que é um método baseado na Reação em Cadeia da Polimerase (PCR). A habilidade desse patógeno se desenvolver nas duas variedades de caqui estudadas também foi verificada na polpa e na casca das frutas em diferentes tempos de incubação e a temperaturas de 10ºC, 20ºC e 30ºC. Os parâmetros de crescimento de L. monocytogenes (duração da fase lag, taxa de crescimento exponencial e tempo de geração) foram obtidos a partir dos dados experimentais. A pesquisa de incidência revelou ausência de L. monocytogenes nas cascas das frutas. Os dados de crescimento obtidos para o patógeno indicam que este pode sobreviver e se multiplicar tanto na polpa quanto na casca dos caquis \'Fuyu\' e \'Rama Forte\', e que a baixa temperatura pode retardar o seu crescimento, mas não evitá-lo.
Brazil is among of the three biggest fruit producer in the world, with a production that is over 39 million tons, a relevant participation in the international market and an increasing participation in the domestic market. However, beyond quantity the quality and safety of food are issues equally demanded by consumers. It has been known that in natura products can contain microbiological contaminants and cooling is normally used to retard microbial development in fresh produce. Psychotrophic microorganisms, such as Listeria monocytogenes, are able to develop under refrigeration. This bacterium has been recognized as an important foodborne pathogen and, due to the severity of the disease and the high mortality in susceptible individuals, it has been deserving the attention of food microbiologists and health professionals. In fruits of low acidity, in which persimmon fruit is included, L. monocytogenes can have conditions to survive and to multiply, because it is not submitted to post harvest treatments. In many countries, including Brazil, persimmon is consumed with its skin, so an external contamination may make the situation even more critical with respect to the product safety. So the objectives of the present study were: (1) to verify the incidence of L. monocytogenes on the skin of \'Fuyu\' and \'Rama Forte\' persimmons (Diospyros kaki) fruits; (2) to study the survival and multiplication of that pathogen on the skin and in the pulp of this fruit at different times and temperatures of incubation; (3) to obtain kinetic values (lag phase duration, generation time and exponential growth). The incidence of L. monocytogenes on the skin of persimmon was verified from March to July in the years of 2005 and 2006. Samples were collected from retail in the city of Campinas, State of Sao Paulo, and from wholesale CEAGESP. A total of 582 fruits were analyzed using the Bax® System, which is a method based on Polymerase Chain Reaction (PCR). The ability of this pathogen to develop in both varieties of persimmons studied was also verified on the surface and in the pulp of the fruits at different times of incubation and at 10ºC, 20ºC and 30ºC. Kinetic values of L. monocytogenes (lag phase duration, generation time and exponential growth) were obtained from experimental data. The incidence survey showed the absence of L. monocytogenes on the skin of the fruit. The growth data showed that this pathogen can grow on the surface as well in the pulp of the \'Fuyu\' and \'Rama Forte\' persimmon fruits and that low temperatures can reduce the generation rate but does not inhibit its growth.

On étudie les potentialités d'action de la consommation de jus de fruits et de vins riches en polyphénols sur modèle pathologique de stress oxydant, l'athérosclérose précoce, d'origine nutritionnelle, ainsi que leur effet protecteur spécifique vis à vis de cette pathologie. Dans une première partie expérimentale, nous avons analysé les polyphénols de trois variétés de jus de framboises (Cardinal, Glen Ample et Tulameen) et deux vins (Kaki et Merlot) par HPLC. Nous avons identifié et quantifié les composants phénoliques de la famille des anthocyanes et des ellagitanins, les deux constituants majeurs des polyphénols de framboise. Leurs compositions diffèrent significativement, en particulier entre Glen Ample et Tulameen. Concernant les vins, les flavan-3-ols (monomères et oligomères) ont été analysés. Les concentrations de chaque composant étaient fondamentalement différents entre les deux vins, sauf pour les dimères. Ceci nous a conduit à aborder l'étude in vivo sur hamster syrien doré recevant un régime riche en lipides et cholestérol, et carencé en antioxydants alimentaires. L'ingestion de Glen Ample (équivalent à 250 mL de jus de framboise par jour pour une homme de 70 kg) inhibe les facteurs pro-oxydants et améliore le statut antioxydant alors que le jus Tulameen a un effet protecteur contre la dyslipidémie. Ces effets peuvent être liés aux ellagitanins et anthocyanes respectivement. Nous avons montré que la consommation de vin à dose nutritionnelle (équivalent à 2 verres par repas pour un homme de 70 kg) améliorait la réactivité vasculaire, la dyslipidémie et le statut antioxydant. Parmi ces effets bénéfiques, aucune différence n'apparaît entre le vin de kaki et le Merlot, ce qui suggère que les dimères de procyanidines sont impliqués dans les effets biologiques des polyphénols
The purpose of this study is to explore the potential of fruit juices and wines consumption rich in polyphenol on pathological models of oxidative stress, diet-induced early atherosclerosis, and to research their specific protective effect against the pathology.In the first part of this work we analyzed the polyphenols in three varieties of raspberry juices (Cardinal, Glen Ample and Tulameen) and two wines (Persimmon and Merlot) by HPLC. We identified and quantified phenolic components of anthocyanins and ellagitannins family, the two major constituents in raspberries polyphenols. Their compositions differed significantly especially between Glen Ample and Tulameen. For wines, flavan-3-ols (monomers and oligomers) were analyzed. Concentrations of each component were fundamentally different in two wines except for procyanidin dimers.These results led us to address in vivo studies on Syrian Golden hamsters fed a high-fat, high-cholesterol diet deprived in dietary antioxidants. Consumption of Glen Ample (equivalent to 250 mL of raspberry juice per day for a 70 kg human) inhibits pro-oxidant factors and improves antioxidant status whereas Tulameen shows a protective effect against dyslipidemia which may be due to its ellagitannins and anthocyanins respectively.Nutritional dose of wines (equivalent to 2 glasses of wine per meal for a 70 kg human) improves vascular reactivity, dyslipidemia and antioxidant status. No difference appeared between persimmon and merlot wine antioxidant properties suggesting that procyanidin dimers are implicated in the biological effects of polyphenols

En esta tesis se realizó la identificación y caracterización de los microorganismos (levaduras y bacterias acéticas) asociados a la producción de vinagres de diferentes frutas con el fin de seleccionar posibles cultivos starters para tener un mejor control del proceso. Se elaboraron vinagres a partir de uva, caqui, fresa y arándano por el método superficial principalmente, aunque, también, se utilizaron diferentes métodos sumergidos. Tras los estudios ecológicos, se realizaron pruebas de inoculación tanto para levaduras como para bacterias acéticas. En general, la inoculación resultó en una clara reducción en el tiempo de producción siendo algunas de las cepas seleccionadas buenas candidatas para utilizarse a nivel industrial. Por otra parte, a nivel tecnológico, se evaluaron diferentes diseños de barricas para mejorar la producción de vinagre por el método superficial. El aumento de la superficie de contacto con el aire es el principal parámetro a modificar para reducir el tiempo de acetificación.
In this thesis, the identification and characterization of microorganisms (yeasts and acetic acid bacteria) associated with the production of different fruit vinegars were carried out in order to select potential starter cultures to have better control of the process. Vinegars from grapes, persimmon, strawberry and highbush blueberry were mainly produced by surface method, but also submerged and Schützenbach methods were tested. After the ecological studies, inoculation tests with yeast and acetic acid bacteria were performed. Overall, inoculation improved the kinetics, shortening the time needed for the vinegar production. Furthermore, some of the strains tested could be good candidates to be used as starter cultures at industrial level. On the other hand, at technological level, the use of wood barrels with a higher air-contact surface facilitated the development of AAB, which is necessary to reduce the acetification time in traditional vinegar production (surface method).

Tesis por compendio
[ES] En las últimas dos décadas, la producción de caqui en España ha aumentado exponencialmente y la superficie de cultivo se ha multiplicado casi por ocho. En la actualidad, la producción de caqui está centralizada en el cultivar 'Rojo Brillante', que es mundialmente apreciado. Sin embargo, esta centralización supone una importante limitación comercial. En la presente Tesis se abordan dos objetivos principales: 1) Optimización de la tecnología pre y postcosecha con el fin de garantizar la calidad del caqui 'Rojo Brillante' durante la frigoconservación y el transporte a mercados internacionales. 2) Evaluación del comportamiento bajo condiciones mediterráneas de variedades introducidas de otras regiones productoras con el fin de ampliar el rango varietal de caqui. El primer objetivo de esta Tesis se logró a través de los estudios presentados en los Capítulos I al V. El segundo objetivo se abordó en los Capítulos VI y VII. En el Capítulo I se esclarecieron las causas del pardeamiento interno del fruto en los envíos a los mercados internacionales. La temperatura a la que se expone la fruta inmediatamente tras la aplicación del tratamiento de desastringencia con altas concentraciones de CO2 se identificó como el principal factor implicado en esta alteración. Los resultados obtenidos mostraron que esta alteración se puede evitar mediante la implementación de un período de atemperado de 24 h después del tratamiento con CO2, antes de conservar las frutas a bajas temperaturas. En el Capítulo II se evaluó la eficacia de un tratamiento de desastringencia recientemente patentado basado en la aplicación de una nueva cera que contiene etanol en su formulación. Los resultados mostraron que esta cera podría ser una alternativa al tratamiento convencional de desastringencia con altas concentraciones de CO2 cuando la fruta se envía a mercados lejanos a bajas temperaturas. La aplicación de la nueva cera antes de conservación en frío provocó la pérdida de astringencia de la fruta tras 30 días a 0 °C, preservando la firmeza y la calidad interna. Los resultados del Capítulo III demostraron que la realización de dos aplicaciones de ácido giberélico (AG) en precosecha permite retrasar el proceso de maduración de la fruta en el árbol con respecto a una sola aplicación. La combinación de AG en precosecha y 1-metilciclopropeno (1-MCP) en postcosecha resultó en una mayor calidad del fruto durante la frigoconservación en comparación con la aplicación únicamente de 1-MCP. Además, la fruta tratada con múltiples aplicaciones de AG mostró una firmeza ligeramente mayor tras de conservación a baja temperatura. En el Capítulo IV se demostró que, paralelamente al retraso de la maduración, el tratamiento con AG también retrasa la senescencia del cáliz, incrementando la calidad externa del fruto. La senescencia del cáliz durante la maduración del fruto se relacionó con una disminución de los parámetros de fluorescencia de clorofila (Fo, Fm y Fv/Fm). En el Capítulo V se estudiaron las condiciones óptimas de almacenamiento del caqui producido bajo cultivo ecológico. Según los resultados, no se deben almacenar los frutos cosechados con firmeza inferior a 30 N. La calidad del fruto durante la conservación dependió de las condiciones de almacenamiento, momento de aplicación del tratamiento de deastringencia y estado de madurez inicial. Por último, en los Capítulos VI y VII se abordó la evaluación bajo condiciones mediterráneas de 14 variedades de caquis no-astringentes procedentes de otros países. Se identificaron las variedades tempranas y tardías que pueden ser potencialmente interesantes para ampliar el período de cosecha en nuestra región. Los estudios postcosecha mostraron que todas las variedades estudiadas presentan una buena aptitud para ser comercializadas en los mercados nacionales y europeos. Sin embargo, la sensibilidad a los daños por frío que presentaron algunas de las variedades estudiadas podría limitar su comercialización a países de ultramar. Además, se observó que la respuesta al tratamiento con 1-MCP, para el control de los daños por frío, dependió en gran medida de la variedad.
[CA] En les últimes dues dècades, la producció de caqui a Espanya ha augmentat exponencialment i la superfície de cultiu s'ha multiplicat quasi per huit vegades. En l'actualitat, la producció de caqui està centralitzada en el la cultivar 'Rojo Brillante', que és mundialment apreciat. Malgrat això, aquesta centralització suposa d'una banda una important limitació comercial, ja que la producció es concentra en un període de collita relativament curt i, d'altra banda implica un alt risc fitosanitari. En la present Tesi s'aborden dos objectius principals: 1) Optimització de la tecnologia pre i postcollita amb la finalitat de garantir la qualitat del caqui 'Rojo brillante' durant la frigoconservació i el transport a mercats internacionals. 2) Avaluació del comportament de varietats introduïdes d'altres regions productores sota condicions mediterrànies amb la finalitat d'ampliar el rang varietal de caqui. En el Capítol I es van esclarir les causes de l l'enfosquiment intern. La temperatura a la qual s'exposa la fruita immediatament després de l'aplicació del tractament de desastringència amb altes concentracions de CO¿ es va identificar com el principal factor implicat en aquesta alteració. Els resultats obtinguts van mostrar que aquesta alteració es pot evitar mitjançant la implementació d'un període de temperat de 24 h després del tractament amb CO¿, abans de transferir la fruita a baixes temperatures. En el Capítol II es va avaluar l'eficàcia d'un tractament de desastringència recentment patentat basat en l'aplicació d'una nova cera que conté etanol en la seua formulació en caquis 'Rojo Brillante' i 'Triumph'. Els resultats van mostrar que aquesta cera podria ser una alternativa al tractament convencional de desastringència amb altes concentracions de CO¿ quan la fruita s'envia a mercats llunyans a baixes temperatures. L'aplicació de la nova cera abans de conservació en fred va provocar la pèrdua d'astringència de la fruita després de 30 dies a 0 °C, preservant la fermesa i la qualitat interna. Els resultats del Capítol III van demostrar que l'aplicació de dos tractaments d'àcid giberèlic (AG) en precollita permet retardar el procés de maduració de la fruita en l'arbre respecte a una sola aplicació. La combinació de AG en precollita i 1-metilciclopropeno (1-MCP) en postcollita va incrementar la qualitat del fruit durant la frigoconservació en comparació amb l'aplicació únicament de 1-MCP. A més, la fruita tractada amb múltiples aplicacions de AG va mostrar una fermesa lleugerament major després de conservació a baixa temperatura; no obstant això, una sola aplicació de AG també va ser eficaç per a previndre la manifestació de danys per fred en la fruita. En el Capítol IV es va demostrar que, paral·lelament al retard de la maduració, el tractament amb AG també retarda la senescència del calze, incrementant la qualitat externa del fruit. La senescència del calze durant la maduració del fruit es va relacionar amb una disminució dels paràmetres de fluorescència de clorofil·la (Fo, Fm i Fv/Fm). En el Capítol V es van estudiar les condicions òptimes d'emmagatzematge del caqui produït baix cultiu ecològic. D'acord amb els resultats obtinguts, no s'han d'emmagatzemar els fruits collits amb fermesa inferior a 30 N. La conservació del fruit va dependre de les condicions d'emmagatzematge, moment d'aplicació del tractament de desastringència i estat de maduresa de la fruita. Finalment, en els Capítols VI i VII es va abordar l'avaluació de 14 varietats de caquis no-astringents. Es van identificar les varietats primerenques i tardanes que poden ser potencialment interessants per a ampliar el període de collita. D'altra banda, els estudis postcollita van mostrar que totes les varietats estudiades presenten una bona aptitud per a ser comercialitzades en els mercats nacionals i europeus. No obstant això, la sensibilitat als danys per fred que van presentar algunes de les varietats estudiades podria limitar la seua comercialització a països d'ultramar. A més, es va observar que la resposta al tractament amb 1-MCP, per al control dels danys per fred, va dependre en gran manera de la varietat.
[EN] In the last two decades, persimmon production in Spain has increased exponentially and the cultivation area has expanded almost eight-fold. The current production of persimmon is focused on the cultivar 'Rojo Brillante', which is appreciated worldwide due to the high quality of the fruit. Nevertheless, centralized production of this single cultivar implies a major commercial limitation as its high volume of production is concentrated in a relative short harvesting period. Furthermore, it also implies a high phytosanitary risk. In this context, this Thesis addresses two main objectives: 1) Optimization of pre- and postharvest technology in order to guarantee the quality of 'Rojo Brillante' persimmon after cold storage and transportation to overseas markets. 2) Evaluation of the behavior of foreign varieties of persimmon under Mediterranean conditions in order to extend the varietal range. The first objective of this Thesis was tackled through the studies presented in Chapters I to V. The second objective was covered in Chapters VI and VII. Chapter I dealt with the causes of internal browning disorder manifested after cold shipment of 'Rojo Brillante' persimmons to overseas markets. The temperature to which fruit is exposed immediately after CO2 deastringency treatment was identified as the main factor involved in this alteration. Our results showed that this disorder can be avoided by implementing an attemperation period of 24 h after the CO2 treatment, before transferring fruit to cold storage. In Chapter II, the effectiveness of a recently patented deastringency treatment based on applying a new wax containing ethanol was assayed in 'Rojo Brillante' and 'Triumph' persimmons. The use of this new ethanol-based wax could be a potential alternative to the conventional CO2 deastringency treatment when the fruit are sent to distant overseas markets at low temperatures. Application of the new wax before cold storage led to loss of fruit astringency after 30 days at 0 °C while preserving fruit firmness and internal quality. The results of Chapter III demonstrated that two applications of gibberellic acid (GA) made it possible to delay the fruit maturity process on the tree more than with just a single application. The combination of GA and 1-methylciclopropene (1-MCP) preserved the fruit quality better than with the application of 1-MCP alone during cold storage. Moreover, the fruit treated by multiple GA applications showed a slightly higher firmness after cold storage. However, a single GA application was also effective in preventing the manifestation of chilling injury (CI) in fruit. Chapter IV demonstrated that in parallel to delaying maturity, the GA treatment also delayed calyx senescence, which meant that the fruit preserved a good appearance. The calyx lobe senescence during fruit ripening was linked to a decrease in all Chlorophyll Fluorescence Imaging (CFI) parameters (Fo, Fm, and Fv/Fm). Chapter V addressed the optimization of storage conditions for organic persimmons. According to our results, fruit harvested with a firmness lower than 30 N must not be stored. Fruit harvested with a higher level of firmness could be stored for up to three weeks depending on the storage conditions, the moment of application of the CO2 deastringency treatment, and the stage of fruit maturity. The longest storage period (3 weeks) was achieved when fruit were harvested with a firmness of around 45 N, submitted to CO2 treatment and then stored at 15 °C. Finally, 14 foreign varieties grown under Mediterranean conditions were evaluated to identify early- and late-season varieties with potential to extend the harvesting period. This is presented in Chapters VI and VII. In general, all the evaluated varieties fulfilled the quality criteria to be commercialized in domestic and European markets. However, sensitivity to CI was variety dependent and response to 1-MCP treatment was also observed to depend on the variety.
This study has been supported by the Instituto Nacional de Tecnología Agraria y Alimentaria de España (INIA) and Fondo Europeo de Desarrollo Regional (FEDER) through the projects RTA 2013-00043-C02-01 and RTA2017-00045-C02-01. In addition, it has been supported by the Valencian Institute for Agricultural Research (Project N° 51910). This study has also been founded by the Consellería de Educación, Investigación, Cultura y Deporte de la Comunidad Valenciana (project GV/2016/183). Ayoub Fathi Najafabadi thanks the INIA for grant FPI-INIA #43 (CPD2015-0151). The authors thank Fomesa Fruitech S.L.U. and Natural Hand S. L. for their technical support, Cooperativa Agrícola Ntra Sra de Loreto for its technical support and for making the plots and fruit used in this study available and Plant Production Department (Instituto Valenciano de Investigaciones Agrarias) for providing the fruit weight data and the photographs of the different varieties.
Fathi Najafabadi, A. (2021). Optimization of postharvest Technology for "Rojo brillante" Persimmon and Introduction of New Varieties in the Mediterranean Area [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/171252
TESIS
Compendio

La thérapie photodynamique (PDT) est une technique utilisée cliniquement pour traiter certaines maladies de la peau, la dégénérescence maculaire liée à l’âge et certains types de cancer. Elle fait intervenir trois composants : une molécule photosensible ou photosensibilisateur (PS), la lumière et l’oxygène. Après administration du PS, celui-ci va se localiser plus ou moins sélectivement dans les zones tumorales où il est alors activé par irradiation lumineuse à une longueur d’onde et une puissance données. Ceci engendre la formation d’espèces réactives de l’oxygène (ROS) très réactives, dont l'oxygène singulet1 O2, qui entraînent la destruction des tissus tumoraux par nécrose ou apoptose. Afin d’améliorer la sélectivité du traitement, différentes pistes sont actuellement exploitées dont l’élaboration de « photodynamic molecular beacons » (PMB). Dans un PMB, le photosensibilisateur (PS) est associé via un peptide à un inhibiteur 1O2, appelé quencher. Ce quencher inhibe la formation d’1O2 tant que le composé n’a pas atteint sa cible. Une fois la zone cancéreuse atteinte, des enzymes spécifiques clivent le peptide, libérant ainsi le PS qui retrouve alors sa capacité à former de l’1O2. Trouver un couple PS/quencher adéquat reste un challenge en PDT. Les propriétés photophysiques particulières des caroténoïdes et leur aptitude à inhiber la production d’1O2 font de ces derniers des quenchers potentiellement utilisables pour l’élaboration de PMBs. Chez les plantes, les caroténoïdes (carotènes et xanthophylles) sont des pigments associés à la photosynthèse, qui ont deux rôles principaux : un rôle de collecteur de lumière et un rôle photoprotecteur en protégeant le(s) système(s) photosynthétique(s) contre les dommages photooxydatifs liés à une exposition trop intense à la lumière. Ceci s’opère, entre autre, via le cycle des xanthophylles. Cette aptitude à capter de l’énergie présente un intérêt potentiel à ne pas négliger dans la perspective de la conception de PMB utilisables en thérapie photodynamique. Dans le cadre de cette thèse en co-tutelle avec la Faculté des Sciences de Bizerte nous avons ciblé les caroténoïdes présents dans trois fruits produits en Tunisie à savoir les kakis (Diospyros kaki L.), les abricots (Prunus armeniaca L.) et les pêches (Prunus persica L.) connus pour leur richesse globale en ces pigments. Divers procédés d’extractions ont été étudiés : (i) L’extraction de type Soxhlet par solvants organiques à pression atmosphérique, utilisée comme référence, (ii) l'extraction accélérée par solvant organique (ASE : Accelerated solvent Extraction) effectuée sous pression, enfin (iii) l'extraction par CO2 supercritique avec l’éthanol comme cosolvant. Pour ces deux derniers procédés, une approche par plan d’expériences (surfaces de réponses) a été utilisée pour identifier les facteurs clé et les conditions optimales d’extractions de divers caroténoïdes (pression, température, débit, % de cosolvant, temps, nombre de cycles). L'analyse par chromatographie liquide à haute performance couplée à la détection UV-Visible et à la spectrométrie de masse a ensuite permis l'identification et la quantification des caroténoïdes présents dans les extraits obtenus, permettant ainsi de comparer les profils caroténoïdiques propres à chaque fruit et les performances de chaque procédé d’extraction. Cette étude ayant révélé un profil caroténoïdique particulièrement intéressant chez le kaki par rapport aux autres fruits, une extraction et une purification des caroténoïdes de ce fruit par chromatographie liquide haute pression préparative a ensuite été effectuée afin de disposer d’une quantité suffisante de chaque caroténoïde, et parfois de leurs isomères conformationnels, en vue de l’étude de leurs propriétés photophysiques (absorption, émission de fluorescence, inhibition d’1O2) et de l’évaluation de leur intérêt potentiel en tant que quencher d’1O2 dans un édifice de type PMB
Photodynamic therapy (PDT) is a clinically used technique for treating skin diseases, age-relatedmacular degeneration but mainly some types of cancer. PDT involves three components: a photosensitive molecule named photosensitizer (PS), light and oxygen. After administration of the PS, this one will be located more or less selectively in tumoral regions where it is activated by light irradiation at appropriate wavelength and power. This leads to the formation of highly reactive and cytotoxic reactive oxygen species (ROS), especially singlet oxygen, resulting in the destruction of the tumor by necrosis or apoptosis. To improve the treatment selectivity, different strategies are being exploited, one of which is the development of "photodynamic molecular beacons" (PMB). In PMB the photosensitizer is linked via a peptide to an inhibitor of 1O2 (quencher). This quencher inhibits the formation of 1O2 as long as the compound has not reached its target, namely cancer cells. In order to inhibit the toxicity of the PS in non-target cells and restore toxicity only close to the biological target, it is necessary to find an adequate PS/quencher couple. This remains a challenge for PDT. Carotenoids are interesting candidates due to their specific photophysical properties and ability to inhibit 1O2, which makes them potential quenchers for building PMBs. In plants, carotenoids (carotenes and xanthophylls) are pigments involved in the photosynthesis, in which they play two main roles: a light collecting role and a protecting role by preserving the photosynthetic systems against photoxydative damages induced by a too intense light exposure. This protection can for instance occur via the well-known xanthophylls cycle. This capacity to catch energy presents a potential interest that should not be neglected in the framework of the design of PMBs usable in photodynamic therapy. Within the framework as part of this PhD thesis in Cotutelle with the Faculty of Sciences of Bizerte, we focused on carotenoids from three fruits produced in Tunisia: persimmon (Diospyros kaki L.), apricot (Prunus armeniaca L.) and peache (Prunus persica L.), known for their global richness in these natural pigments. Three extraction processes were investigated: (i) the Soxhlet extraction based on the use of organic solvent at atmospheric pressure and used as reference, (ii) the accelerated solvent extraction (ASE) using organic solvent under high pressure, and (iii) the supercritical fluid extraction (SFE) using supercritical CO2 and ethanol as cosolvent. For these two last processes, a design of experiments (Surface Response Design) was used to identify the key factors and optimal extraction conditions of various carotenoids (pressure, temperature, flow, % cosolvent, time, number of cycles). Then, HPLC-PDA coupled with mass spectrometry (MS) enabled the identification and quantification of carotenoids from the extracts. Thus it was possible to compare the profiles in carotenoids content from each fruit as well as the performances of each extraction process. This study showed that the carotenoidic profile in the persimmon was the most interesting as compared to the profiles in the two other fruits. Extraction and purification of the carotenoids from persimmon by preparative high pressure liquid chromatography were then performed in order to have a sufficient amount of each carotenoid and sometimes of their conformational isomers. We finally performed a study of their photophysical properties (absorption, fluorescence emission, 1O2 inhibition) in order to evaluate their potential as 1O2 quencher in molecular construction such as a PMB