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J Usall - One of the best experts on this subject based on the ideXlab platform.
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influence of temperature on decay mycelium development and sporodochia production caused by monilinia fructicola and m laxa on stone fruits
Food Microbiology, 2017Co-Authors: M Bernat, C. Casals, J Segarra, J UsallAbstract:Brown rot on peaches and Nectarines caused by Monilinia spp. results in significant economic losses in Europe. Experiments were conducted to study the effects of temperature (0–33 °C) on the temporal dynamics of decay and mycelium development and the subsequent sporulation on peaches and Nectarine fruit infected by M. laxa and M. fructicola. The rates of decay and mycelium development increased with temperature from 0 °C to 25 °C for both Monilinia species. At 0 °C, decay was faster for M. laxa (0.20 cm2 days−1) than for M. fructicola (0.07 cm2 days−1); indeed, M. laxa was able to develop mycelia and sporodochia, but M. fructicola was not. At 4 and 20 °C, there were no differences in decay and mycelia development between the two Monilinia species. When temperature increased from 25 to 33 °C, the rates of fungal decay and mycelium development decreased. At 30 and 33 °C, M. fructicola decayed faster (0.94 and 1.2 cm2 days−1, respectively) than M. laxa (0.78 and 0.74 cm2 days−1, respectively) and could develop mycelia and produce sporodochia, whereas M. laxa failed at 33 °C. These results indicated that M. fructicola is better adapted to high temperatures, whereas M. laxa is better adapted to low temperatures. These results can be used to predict the relative importance of the two species during the season at a given site and to improve management strategies for brown rot in areas where both species are present.
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formulation development of the biocontrol agent bacillus subtilis strain cpa 8 by spray drying
Journal of Applied Microbiology, 2012Co-Authors: V Yanezmendizabal, R Torres, J Usall, I Vinas, C Solsona, Maribel Abadias, Neus TeixidoAbstract:Aims: To prepare commercially acceptable formulations of Bacillus subtilis CPA-8 by spray-drying with long storage life and retained efficacy to control peach and Nectarine brown rot caused by Monilinia spp. Methods and Results: CPA-8 24-h- and 72-h-old cultures were spray dried using 10% skimmed milk, 10% skimmed milk plus 10% MgSO4, 10% MgSO4 and 20% MgSO4 as carriers/protectants. All carriers/protectants gave good percentages of powder recovery (28–38%) and moisture content (7–13%). CPA-8 survival varied considerably among spray-dried 24-h- and 72-h-old cultures. Seventy-two hours culture spray dried formulations showed the highest survival (28–32%) with final concentration products of 1·6–3·3 × 109 CFU g−1, while viability of 24-h-old formulations was lower than 1%. Spray-dried 72-h-old formulations were selected to subsequent evaluation. Rehydration of cells with water provided a good recovery of CPA-8 dried cells, similar to other complex rehydration media tested. Spray-dried formulations stored at 4 ± 1 and 20 ± 1°C showed good shelf life during 6 months, and viability was maintained or slightly decreased by 0·2–0·3-log. CPA-8 formulations after 4- and 6 months storage were effective in controlling brown rot caused by Monilinia spp. on Nectarines and peaches resulting in a 90–100% reduction in disease incidence. Conclusions: Stable and effective formulations of biocontrol agent B. subtilis CPA-8 could be obtained by spray-drying. Significance and Impact of the Study: New shelf-stable and effective formulations of a biocontrol agent have been obtained by spray-drying to control brown rot on peach.
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control of monilinia spp on stone fruit by curing treatments part i the effect of temperature exposure time and relative humidity on curing efficacy
Postharvest Biology and Technology, 2010Co-Authors: C. Casals, N Teixido, I Vinas, S Llaurado, J UsallAbstract:Abstract Monilinia spp. are the most important cause of brown rot on peaches and Nectarines. In many countries, no postharvest chemical treatments of stone fruit are allowed and alternative postharvest treatments are urgently required. The effect of curing treatments at different temperatures, exposure times and relative humidity (RH) to control brown rot was studied. Three curing temperatures were tested (40, 45 and 50 °C) at different exposure times (ranging from 30 min to 6 h). Curing at 50 °C for 2 h successfully increased brown rot control (95%) after fruit were incubated at 20 °C and 85% RH for 5 d after treatment. Longer exposure time was required to achieve the same level of brown rot control at lower curing temperatures. Four relative humidity (RH) levels (60%, 80%, 90% and 99%) were also tested during curing at 50 °C for 1, 2, 3 and 4 h. Brown rot control at 99% or 90% RH for 3 or 4 h were the same, achieving control at higher than 95%. At lower RH levels (60% and 80%), more exposure time was required to achieve the same control as at the highest RH (90% and 99%). Complete control of disease development was achieved when four varieties of peach and Nectarine fruit artificially inoculated with either Monilinia laxa or Monilinia fructicola were cured at 50 °C for 2 h and 95–99% RH. Curing at 50 °C for 2 h and 95–99% RH had a positive effect on fruit quality, with significantly (P
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control of monilinia spp on stone fruit by curing treatments part ii the effect of host and monilinia spp variables on curing efficacy
Postharvest Biology and Technology, 2010Co-Authors: C. Casals, N Teixido, I Vinas, J Cambray, J UsallAbstract:Abstract In previous experiments, we identified that a postharvest curing treatment (50 °C for 2 h and 95–99% RH) satisfactorily controlled brown rot on several peach and Nectarine varieties. In the present complementary study, the effect of fruit maturity, fruit with natural infection, time of infection and inoculum concentration on the curing efficacy was investigated. Different maturity levels affected curing efficacy. As fruit maturity increased, the efficacy of a postharvest curing treatment decreased from 95% control of brown rot (harvest mature fruit) to 65% (the most advanced mature fruit). The effect of Monilinia fructicola infection time prior to treatment also affected the curing efficacy. When the infection time was increased from 0 to 48 h, brown rot control decreased from 90% to 64%. A factorial experiment design was used to investigate the effect of M. fructicola conidial concentrations (103, 104, 105 and 106 conidia mL−1) at different exposure times (1, 2, 3 and 4 h) on curing efficacy. Overall, longer curing exposure times (3 or 4 h) were required when higher conidial concentrations were applied to the wounded fruit. At the lowest M. fructicola conidial concentration tested (103 conidia mL−1), 2 h of curing exposure resulted in 100% and 94% brown rot control in ‘Andros’ peaches and ‘Flames Kid’ Nectarines, respectively. A high level of brown rot control was also achieved when naturally infected fruit with Monilinia spp. were cured. When fruit with natural inoculum were surface sterilized prior to the curing treatment, complete brown rot control resulted. This findings support our earlier demonstration that a postharvest curing treatment is an attractive non-chemical strategy for use in conventional and organic stone fruit brown rot management.
Sebastien Lurol - One of the best experts on this subject based on the ideXlab platform.
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effects of storage temperature storage duration and subsequent ripening on the physicochemical characteristics volatile compounds and phytochemicals of western red Nectarine prunus persica l batsch
Journal of Agricultural and Food Chemistry, 2014Co-Authors: Christophe Aubert, P Bony, Guillaume Chalot, Pierre Landry, Sebastien LurolAbstract:Western Red Nectarines, harvested at commercial maturity, were stored for up to 20 days at 1, 4, or 8 °C and then transferred to 25 °C for 0 or 4 days. The main physicochemical attributes, phytochemicals, and volatile compounds were then determined. During storage and ripening, firmness, titratable acidity, organic acids, and C6 volatile compounds decreased, whereas ethylene production, lactones, and C13 norisoprenoids greatly increased. Soluble solids content, sugars, and polyphenols remained quite constant during both stages. During storage, vitamin C decreased and carotenoids did not significantly change, whereas both greatly increased during ripening. Increased time of low-temperature storage has been found to decrease lactones and C13 norisoprenoids in Nectarine and, consequently, to limit its aroma during maturation. Finally, Western Red Nectarine was found hardly chilling injury sensitive, and trends for sugars, polyphenols and lactones observed in this study were contrary to those generally report...
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effects of storage temperature storage duration and subsequent ripening on the physicochemical characteristics volatile compounds and phytochemicals of western red Nectarine prunus persica l batsch
Journal of Agricultural and Food Chemistry, 2014Co-Authors: Christophe Aubert, P Bony, Guillaume Chalot, Pierre Landry, Sebastien LurolAbstract:Western Red Nectarines, harvested at commercial maturity, were stored for up to 20 days at 1, 4, or 8 °C and then transferred to 25 °C for 0 or 4 days. The main physicochemical attributes, phytochemicals, and volatile compounds were then determined. During storage and ripening, firmness, titratable acidity, organic acids, and C6 volatile compounds decreased, whereas ethylene production, lactones, and C13 norisoprenoids greatly increased. Soluble solids content, sugars, and polyphenols remained quite constant during both stages. During storage, vitamin C decreased and carotenoids did not significantly change, whereas both greatly increased during ripening. Increased time of low-temperature storage has been found to decrease lactones and C13 norisoprenoids in Nectarine and, consequently, to limit its aroma during maturation. Finally, Western Red Nectarine was found hardly chilling injury sensitive, and trends for sugars, polyphenols and lactones observed in this study were contrary to those generally reported in the literature for chilling-injured fruit.
Themis J Michailides - One of the best experts on this subject based on the ideXlab platform.
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propiconazole sensitivity in populations of geotrichum candidum the cause of sour rot of peach and Nectarine in california
Plant Disease, 2012Co-Authors: Mohammad A Yaghmour, J E Adaskaveg, Richard M Bostock, Themis J MichailidesAbstract:Abstract The sour rot pathogen of peach (Prunus persica var. persica) and Nectarine (P. persica var. nectarina) fruit, Geotrichum candidum, can cause significant postharvest losses in California fruit production. Harvested peach and Nectarine fruit, treated with fungicide at the packinghouse but culled after inspection because of disease and defects, were collected for further assessment and pathogen isolation. The incidence of fruit with sour rot was 3.4 ± 1.0 to 26.1 ± 2.3%. Culled fruit that had been treated with postharvest fungicides from five different orchards had a significantly higher incidence of sour rot when compared with nontreated fruit. Since August 2006, propiconazole has been used as a postharvest treatment to protect peach and Nectarine fruit against sour rot. The mean effective concentration that inhibits 50% of mycelial growth (EC50) value of 57 isolates of G. candidum to propiconazole collected before and during 2006 was 0.072 μg/ml. However, 61 isolates from propiconazole-treated, di...
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effects of wounding inoculum density and biological control agents on postharvest brown rot of stone fruits
Plant Disease, 1998Co-Authors: Chuanxue Hong, Themis J Michailides, B A HoltzAbstract:ABSTRACT The effects of wounding, inoculum density, and three isolates (New, Ta291, and 23-E-6) of Trichoderma spp. and one isolate (BI-54) of Rhodotorula sp. on postharvest brown rot of stone fruits were determined at 20°C and 95% relative humidity (RH). Brown rot was observed frequently on wounded Nectarine, peach, and plum fruits inoculated with two spores of Monilinia fructicola per wound, and occasionally on unwounded Nectarine and peach fruits inoculated with the same spore load. Brown rot was observed on wounded plums only. A substantial increase in lesion diameter of brown rot was also recorded on wounded Nectarines and peaches inoculated with suspensions of ≤20 spores and ≤200 spores per wound, respectively, compared with unwounded fruit. At concentrations of 107 and 108 spores per ml, all Trichoderma isolates substantially reduced brown rot on peaches (63 to 98%) and plums (67 to 100%) when fruits were inoculated with M. fructicola following the application of a biological control agent. Similar...
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significance of thinned fruit as a source of the secondary inoculum of monilinia fructicola in california Nectarine orchards
Plant Disease, 1997Co-Authors: Chuanxue Hong, Brent A Holtz, David P Morgan, Themis J MichailidesAbstract:The significance of thinned fruit as a source of secondary inoculum in the spread of brown rot, caused by Monilinia fructicola, under semi-arid weather conditions of the San Joaquin Valley in California, was investigated in seven Nectarine orchards in 1995 and 1996. Between 6 and 60% (depending on the orchard) of thinned fruit showed sporulation by M. fructicola. Brown rot was significantly less severe at preharvest (five orchards) and postharvest (one orchard) on fruit harvested from trees in plots from which thinned fruit were completely removed than on those in plots from which thinned fruit were not removed. M. fructicola sporulated more frequently on thinned fruit placed into irrigation trenches than on those left on the dry berms in tree rows. The incidence of preharvest fruit brown rot increased exponentially as the density of thinned fruit increased on the orchard floor. These results suggest that thinned fruit left on the floor of Nectarine orchards can be a significant inoculum source of secondary infections. Removal or destruction of thinned fruit should reduce brown rot in Nectarine and possibly other stone fruit orchards under semi-arid California conditions.
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prune plum and Nectarine as hosts of trichothecium roseum in california orchards
Plant Disease, 1997Co-Authors: C X Hong, Themis J MichailidesAbstract:Trichothecium roseum (Pers.:Fr.) Link was frequently observed (up to 21%) on mummified peach (Prunus persica (L.) Batsch), Nectarine (P. persica (L.) Batsch var. nectarina (Aiton) Maxim.), plum (P. salicina Lindl.), and prune (P. domestica L.) fruits in orchards during a 1995 to 1996 survey. Pink mold rot caused by T. roseum was also frequently observed (at about the 1 to 2% level) on a number of samples of prune fruit collected from commercial orchards in Glenn, Butte, Madera, Fresno, and Tulare counties in 1996, after storage at 4°C for 7 days and then 20°C for 4 days. Wounded and nonwounded prune (cv. French), plum (cv. Casselman), peach (cv. Fairtime), and Nectarine (cv. Spring Bright) fruits were infected after inoculation with a drop (20 μl) of T. roseum suspension (5 × 105 conidia/ml). Characteristic pink sporulation covered the surface of most fruit 7 days after inoculation. Conidia of T. roseum completely covered all wounded and nonwounded prune fruit, sparsely on the wounded plum fruit, and dens...
C. Casals - One of the best experts on this subject based on the ideXlab platform.
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influence of temperature on decay mycelium development and sporodochia production caused by monilinia fructicola and m laxa on stone fruits
Food Microbiology, 2017Co-Authors: M Bernat, C. Casals, J Segarra, J UsallAbstract:Brown rot on peaches and Nectarines caused by Monilinia spp. results in significant economic losses in Europe. Experiments were conducted to study the effects of temperature (0–33 °C) on the temporal dynamics of decay and mycelium development and the subsequent sporulation on peaches and Nectarine fruit infected by M. laxa and M. fructicola. The rates of decay and mycelium development increased with temperature from 0 °C to 25 °C for both Monilinia species. At 0 °C, decay was faster for M. laxa (0.20 cm2 days−1) than for M. fructicola (0.07 cm2 days−1); indeed, M. laxa was able to develop mycelia and sporodochia, but M. fructicola was not. At 4 and 20 °C, there were no differences in decay and mycelia development between the two Monilinia species. When temperature increased from 25 to 33 °C, the rates of fungal decay and mycelium development decreased. At 30 and 33 °C, M. fructicola decayed faster (0.94 and 1.2 cm2 days−1, respectively) than M. laxa (0.78 and 0.74 cm2 days−1, respectively) and could develop mycelia and produce sporodochia, whereas M. laxa failed at 33 °C. These results indicated that M. fructicola is better adapted to high temperatures, whereas M. laxa is better adapted to low temperatures. These results can be used to predict the relative importance of the two species during the season at a given site and to improve management strategies for brown rot in areas where both species are present.
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control of monilinia spp on stone fruit by curing treatments part i the effect of temperature exposure time and relative humidity on curing efficacy
Postharvest Biology and Technology, 2010Co-Authors: C. Casals, N Teixido, I Vinas, S Llaurado, J UsallAbstract:Abstract Monilinia spp. are the most important cause of brown rot on peaches and Nectarines. In many countries, no postharvest chemical treatments of stone fruit are allowed and alternative postharvest treatments are urgently required. The effect of curing treatments at different temperatures, exposure times and relative humidity (RH) to control brown rot was studied. Three curing temperatures were tested (40, 45 and 50 °C) at different exposure times (ranging from 30 min to 6 h). Curing at 50 °C for 2 h successfully increased brown rot control (95%) after fruit were incubated at 20 °C and 85% RH for 5 d after treatment. Longer exposure time was required to achieve the same level of brown rot control at lower curing temperatures. Four relative humidity (RH) levels (60%, 80%, 90% and 99%) were also tested during curing at 50 °C for 1, 2, 3 and 4 h. Brown rot control at 99% or 90% RH for 3 or 4 h were the same, achieving control at higher than 95%. At lower RH levels (60% and 80%), more exposure time was required to achieve the same control as at the highest RH (90% and 99%). Complete control of disease development was achieved when four varieties of peach and Nectarine fruit artificially inoculated with either Monilinia laxa or Monilinia fructicola were cured at 50 °C for 2 h and 95–99% RH. Curing at 50 °C for 2 h and 95–99% RH had a positive effect on fruit quality, with significantly (P
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control of monilinia spp on stone fruit by curing treatments part ii the effect of host and monilinia spp variables on curing efficacy
Postharvest Biology and Technology, 2010Co-Authors: C. Casals, N Teixido, I Vinas, J Cambray, J UsallAbstract:Abstract In previous experiments, we identified that a postharvest curing treatment (50 °C for 2 h and 95–99% RH) satisfactorily controlled brown rot on several peach and Nectarine varieties. In the present complementary study, the effect of fruit maturity, fruit with natural infection, time of infection and inoculum concentration on the curing efficacy was investigated. Different maturity levels affected curing efficacy. As fruit maturity increased, the efficacy of a postharvest curing treatment decreased from 95% control of brown rot (harvest mature fruit) to 65% (the most advanced mature fruit). The effect of Monilinia fructicola infection time prior to treatment also affected the curing efficacy. When the infection time was increased from 0 to 48 h, brown rot control decreased from 90% to 64%. A factorial experiment design was used to investigate the effect of M. fructicola conidial concentrations (103, 104, 105 and 106 conidia mL−1) at different exposure times (1, 2, 3 and 4 h) on curing efficacy. Overall, longer curing exposure times (3 or 4 h) were required when higher conidial concentrations were applied to the wounded fruit. At the lowest M. fructicola conidial concentration tested (103 conidia mL−1), 2 h of curing exposure resulted in 100% and 94% brown rot control in ‘Andros’ peaches and ‘Flames Kid’ Nectarines, respectively. A high level of brown rot control was also achieved when naturally infected fruit with Monilinia spp. were cured. When fruit with natural inoculum were surface sterilized prior to the curing treatment, complete brown rot control resulted. This findings support our earlier demonstration that a postharvest curing treatment is an attractive non-chemical strategy for use in conventional and organic stone fruit brown rot management.
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Application of radio frequency heating to control brown rot on peaches and Nectarines.
Postharvest Biology and Technology, 2010Co-Authors: C. Casals, Immaculada Viñas, A. Landl, P. Picouet, Rosario Torres, Rosario Torres, Rosario Torres, J UsallAbstract:Abstract Brown rot caused by Monilinia spp. is a serious postharvest disease affecting stonefruit. Currently, no chemical fungicide is allowed to be applied to stonefruit postharvest in Spain, which creates the need to develop effective postharvest treatments. This is the first report using radiofrequency (RF) heating to control brown rot in peaches and Nectarines artificially inoculated with Monilinia fructicola or with natural Monilinia spp. inoculum. From preliminary studies, a RF treatment at 27.12 MHz, with 17 mm distance between fruit and upper electrode and 18 min exposure time was selected as effective conditions to control brown rot in peaches without affecting fruit quality. This RF treatment was investigated to control M. fructicola inoculated 0, 24 and 48 h before RF treatment and using inoculum concentrations of 10 3 , 10 4 and 10 5 conidia mL −1 . The average brown rot incidence ranged from 44–82% to 63–100% in ‘Summer Rich’ and ‘Placido’ peaches, respectively. Brown rot reduction did not generally depend on the time of inoculation. RF treatment significantly decreased the incidence of brown rot in ‘Summer Rich’ peaches inoculated at 10 3 , 10 4 and 10 5 conidia mL −1 , whereas in ‘Placido’ peaches, brown rot was only reduced when fruit were inoculated at 10 3 conidia mL −1 . The RF treatment was also investigated in naturally infected fruit where the Monilinia spp. development was completely inhibited in both ‘Summer Rich’ and ‘Placido’ peaches. No brown rot control was observed in Nectarine fruit artificially inoculated or with natural inoculum.
Carlos H. Crisosto - One of the best experts on this subject based on the ideXlab platform.
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post harvest uv b irradiation induces changes of phenol contents and corresponding biosynthetic gene expression in peaches and Nectarines
Food Chemistry, 2014Co-Authors: Claudia Scattino, Antonella Castagna, Susanne Neugart, Helen Chan, Monika Schreiner, Pietro Tonutti, Carlos H. Crisosto, Annamaria RanieriAbstract:In the present study the possibility of enhancing phenolic compound contents in peaches and Nectarines by post-harvest irradiation with UV-B was assessed. Fruits of ‘Suncrest’ and ‘Babygold 7’ peach and ‘Big Top’ Nectarine cultivars were irradiated with UV-B for 12 h, 24 h and 36 h. Control fruits underwent the same conditions but UV-B lamps were screened by benzophenone-treated polyethylene film. The effectiveness of the UV-B treatment in modulating the concentration of phenolic compounds and the expression of the phenylpropanoid biosynthetic genes, was genotype-dependent. ‘Big Top’ and ‘Suncrest’ fruits were affected by increasing health-promoting phenolics whereas in ‘Babygold 7’ phenolics decreased after UV-B irradiation. A corresponding trend was exhibited by most of tested phenylpropanoid biosynthesis genes. Based on these results UV-B irradiation can be considered a promising technique to increase the healthpromoting potential of peach fruits and indirectly to ameliorate the aesthetic value due to the higher anthocyanin content.
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comparative transcript profiling of a peach and its Nectarine mutant at harvest reveals differences in gene expression related to storability
Tree Genetics & Genomes, 2013Co-Authors: Carlos H. Crisosto, Susan Lurie, Anurag Dagar, Clara Pons Puig, Cristina Marti Ibanez, F Ziliotto, Claudio Bonghi, Haya Friedman, Antonio GranellAbstract:Gene expression at harvest was compared for two stone fruit cultivars, a peach and its near-isogenic Nectarine mutant, using two microarray platforms, μPEACH1.0 and ChillPeach. Together, both platforms covered over 6,000 genes out of which 417 were differ- entially expressed between the fruits of the two cultivars at a p value of 0.05. A total of 47 genes in Nectarine and 60 genes in peach were at least twofold higher relative to each other. Nectarine had much better storage character- istics than peach and could be stored for over 5 weeks at 5 °C without storage disorders. In an attempt to determine whether gene expression at harvest could give an indica- tion of storage potential, the expression analysis of the two cultivars was compared to that of two genotypes with different sensitivities to chilling injury. Principal compo- nent analysis of gene expression results across four fruit types differing in chilling sensitivity resulted in 41 genes whose expression levels separated the fruits according to sensitivity to storage disorders, suggesting that the genes have a role in cold response adaptation.
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segregation of peach and Nectarine prunus persica l batsch cultivars according to their organoleptic characteristics
Postharvest Biology and Technology, 2006Co-Authors: Carlos H. Crisosto, Gemma Echeverria, Gayle M Crisosto, Jaume PuyAbstract:Cultivar segregation according to the sensory perception of their organoleptic characteristics was attempted by using trained panel data evaluated by principal component analysis of four sources per cultivar of 23 peach and 26 Nectarine cultivars as a part of our program to develop minimum quality indexes. Fruit source significantly affected cultivar ripe soluble solids concentration (RSSC) and ripe titratable acidity (RTA), but it did not significantly affect sensory perception of peach or Nectarine flavor intensity, sourness or aroma by the trained panel. For five out of the 49 cultivars tested, source played a role in perception of sweetness. In all of these cases when a source of a specific cultivar was not classified in the proposed organoleptic group it could be explained by the fruit having been harvested outside of the commercial physiological maturity (immature or over-mature) for that cultivar. The perception of the four sensory attributes (sweetness, sourness, peach or Nectarine flavor intensity, peach or Nectarine aroma intensity) was analyzed by using the three principal components, which accounted for 92 and 94% of the variation in the sensory attributes of the tested cultivars for peach and Nectarine, respectively. Season did not significantly affect the classification of one cultivar that was evaluated during these two seasons. By plotting organoleptic characteristics in PC1 and PC2 (∼76%) for peach and Nectarine, cultivars were segregated into groups (balanced, tart, sweet, peach or Nectarine aroma and/or peach or Nectarine flavor intensity) with similar sensory attributes; Nectarines were classified into five groups and peaches into four groups. Based on this information, we recommend that cultivars should be classified in organoleptic groups and development of a minimum quality index should be attempted within each organoleptic group rather than proposing a generic minimum quality index based on the ripe soluble solids concentration (RSSC). This organoleptic cultivar classification will help to match ethnic preferences and enhance current promotion and marketing programs.
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browning potential phenolic composition and polyphenoloxidase activity of buffer extracts of peach and Nectarine skin tissue
Journal of the American Society for Horticultural Science, 1995Co-Authors: Guiwen W Cheng, Carlos H. CrisostoAbstract:The relationship of phenolic composition and polyphenoloxidase activity (PPO, E.C. 1.14.18.1) to browning potential (BP) was studied in buffer extracts of peach (Prunuspersica L. Batsch) and Nectarine (P. persica var. Nectarine (L.) Batsch) fruit skin. The BP varied among cultivars with 'Flavorcrest' having the highest value and 'Maycrest' the lowest. On average, over 83% of the browning measured at the end of the 5-hour incubation occurred during the first hour. The total soluble phenolics (TSP), the total anthocyanin (TA), and glutathione content (GLU) varied among cultivars, but were not significantly correlated to the BP. Of the phenolics determined by HPLC, only chlorogenic acid had a significant positive correlation and epicatechin a significant negative correlation with BP by the first hour of incubation. The PPO activity, ranging from 4 to 11 optical density units per gram dry weight per minute among peaches and Nectarines, was not significantly correlated with BP. However, no browning was detected if the buffer extract was previously boiled. These results indicated that browning in the buffer extracts of peach and Nectarine skin tissue depends on the presence of PPO activity and chlorogenic acid, which are major contributors to enzymatic browning. Fruit browning, as aconsequence of bruising, is due to phenolic oxidation (Mathew and Parpia, 1971; Mayer and Harel, 1979; Vamos-Vigyazo, 1981). The destruction of fruit cellular compartmentation allows the phenolic substrates to be accessible to PPOs which catalyze the phenolic oxidation (Mayer and Harel, 1979). The concentration and composition of phenolic compounds andor activity of PPOs are often the major factors determining tissue browning development and intensity (Mathew and Parpia, 1971; Mayer and Harel, 1979). Furthermore, natural chemicals with antioxidant properties such as thio compounds may also play an important role in fruit browning development (Liyanage et al., 1993; Singleton et al., 1985). Due to the importance of visual appearance as a produce cosmetic quality parameter, tissue browning has long gained attention from horticultural researchers (Vamos-Vigyazo, 198 1). While numerous studies have used juice, whole fruit and fruit flesh systems, few of them have used skin tissue. Research on fruit skin browning, as aresult of friction damage, has only been reported for pears (Mellenthin and Wang, 1974; Ranadive and Haard, 1971). The potential for skin browning on other species including peach and Nectarine have not been studied at all. Peach and Nectarine skin discoloration is becoming an impor- tant problem for the California stone fruit industry especially on peach cultivars such as 'Flavorcrest', 'Elegant Lady', and 'O'Henry', and Nectarine cultivars such as 'Fantasia', 'Royal Giant', and 'Flaming Red'. This skin cosmetic disorder is charac- terized by the formation of dark brown or black spots and/or light brown spots on the surface of the fruit. Dark brown and black spots commonly called black staining or inking occur as a consequence of abrasion damage to epidermal cells in combination with con- taminants (Cheng and Crisosto, 1994; Crisosto et al., 1992, 1993), but light brown spots commonly called skin browning may simply Receivedforpublication2Nov. 1994. Accepted forpublication 10Apr. 1995. This study was funded by a grant from the Califomia Tree Fruit Agreement. We thank Adel A. Kader and Betty Hess for their cooperation. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regula- tions, this paper therefore must be hereby marked advertisement solely to indicate this fact. 'Postdoctoral research associate. ?Assistant pomologist.
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orchard factors affecting postharvest stone fruit quality
Hortscience, 1995Co-Authors: Carlos H. Crisosto, Randall S Johnson, T M Dejong, K R DayAbstract:Although stone fruit quality cannot be improved, only maintained, after harvest, little research has been conducted on the influence of preharvest factors on stone fruit postharvest quality and potential postharvest life. We believe that the maximum fruit quality for each cultivar can be achieved only by understanding the roles of preharvest factors in fruit quality. This article reviews the influences of orchard factors, such as mineral nutrition, irrigation, crop load, and fruit canopy position on fruit quality, market life potential, and internal breakdown (IB). The literature indicates that quality, market life, and IB are related to preharvest factors. Thus, there is a need to continue studying these factors to deliver high quality fruit to the consumer. In recent years the production of stone fruits has increased rapidly, but consumption has remained low at -2.7 k g . y e d per capita for Nectarines and peaches and -0.6 kg.yearl per capita for plums and fresh prunes (U.S. Dept. of Agr., 1994). Surveys conducted to explain the low rate of consumption of stone fruits found that consumers were botheredmainly by lackofflavorand IB problems(Bruhnetal., 1991). Since production is still increasing, more attention must be given to the production and delivery of high-quality stone fruits to increase consumer demand. Studies have associated high consumer acceptance with high soluble solids concentration (SSC) in many commodities (Kader, 1994; Parker et al., 1991), but there are more factors involved, such as acidity (Kader, 1994; Peterson and Ivans, 1988), SSC/acidity ratio (Kader, 1994; Nelson, 1985; Rodan, 1988), phenolics (Robertson and Meredith, 1989), and volatiles (Romani, 1971). In peach (Pruws persica (L.) Batsch], plum (Prumrs salicina Lindel.), and Nectarine [Prunus persica var. Nectarine (L.) Batsch], there is limited information on the relationship between consumer acceptance and ripe fruit chemical composition (Claypool, 1977; Kader, 1994; Mitchell et al., 1990). Since we do not have enough information on this subject, we are not able to propose any quality standards without detailed studies to support them (Crisosto, 1994a). One important complex cause of quality deterioration and consumer complaints in apricots (Prunus armeniaca L.), peaches, Nectarines, plums, and prunes (Pmnusdamesrica L.) is the presence of flesh browning, flesh mealiness, darkened pit cavity, flesh translucence, red pigment accumulation (bleeding), and loss of flavor (Crisosto et al., 1995a, 1995b; Mitchell and Kader, 1989). These symptoms result from IB, which is also called chilling injury, dry fruit, or woolliness. 1B normally appears during prolonged cold storage andor after ripening at‘room temperature following cold storage. This disorder is the main limitation to long-term storage and shipping to distant markets for IB-susceptible cultivars. There is little published information on the possible influence of preharvest factors on IB incidence (Claypool, 1977; Saenz, 1991). During the past I O years, increased research emphasis has been
