Progress 03/01/00 to 09/30/07
Outputs
OUTPUTS: Expression of resistance is dominant in a F1 hybrid of a cross between tomato (Lycopersicon esculentum) and the nightshade Solanum lycopersicoides. Resistance of this nightshade to B. cinerea is based on induced fungal death. We have completed mapping of quantitative trait loci (QTL) for resistance to B. cinerea in an introgression line population derived from a cross between tomato and S. lycopersicoides. These introgression lines were derived from several generations of backcrosses. They contain chromosomal segments from the wild nightshade parent in the background of tomato. We have used spot inoculation of detached leaves to detect differences in gray mold resistance by measuring frequencies of lesion expansion, lesion diameters, and sporulation. We have identified quantitative trait loci (QTL) for resistance that lower infection frequency on four different chromosomes. A resistance QTL slowing the rate of lesion expansion was found on another chromosome. Two
susceptibility QTL were identified, one increasing infection frequency, the other accelerating lesion expansion. A susceptibility QTL and a resistance QTL have been verified by comparing phenotypes and markers in segregating progeny of a heterozygous parent. We almost completed measuring the effect of a second resistance QTL, concluding that this QTL has a rather the small effect on the phenotypic variation of the trait. Experiments have begun to assess the effect of a third resistance QTL. The QTL with the largest effect can eventually be used for fine-mapping of the most important resistance locus. Objective 2: Analysis of gene expression during gray mold infection We previously reported on an acidic glucanase that was specifically induced in the resistant nightshade after infection with B. cinerea. The acidic glucanase gene does not map to any of the resistance QTL we have identified. Thus, it is more likely that transcriptional activation and not enzymatic activity is related to
Botrytis resistance. Objective 3: Contribution of antifungal compounds to gray mold resistance We have studied the contribution of a floral defensin to defense and reproductive development in transgenic tomato plants. The frequency of infection by B. cinerea was reduced in transgenic plants with elevated levels of defensin expression compared to from untransformed control plants. On the contrary, seed production and fruit size were reduced by both overexpressing and by silencing defensin. The reason for this fertility defect has been traced to male sterility. Fruit development was delayed as a result of defensin overexpression. It, thus, appears that floral defensins of tomato are involved in both reproductive development and defense.
PARTICIPANTS: Collaborator: Dr. Roger Chetelat, Department of Plant Sciences, University of California Davis Training: Joel Davis, Faculty Research Associate
TARGET AUDIENCES: The California Tomato Commission and the Botrytis research community
Impacts
The tomato lines we have identified as partially resistant to B. cinerea will be useful to seed companies and growers for development of improved germplasm. This fungus is difficult to control because it causes infections that remain dormant in the field and develop into fruit decay during post-harvest storage. Crop losses of up to 50% are not uncommon. Strategies for controlling Botrytis are limited by the emergence of strains that are resistant to one or several groups of fungicides. Most registered fungicides are protective in their action and will not control gray mold once the fungus is established, which limits effective control to pre-harvest applications of fungicides. Our long-term goal will remain isolation of genes that confer resistance to Botrytis. Because this fungus has a broad host range, these types of genes could be used to protect unrelated crop species against this fungus. Given the limited success of chemical fungicides, genetic improvement of
tomatoes is the most economical and environmentally appropriate strategy for disease control. In addition, reduction of the amount of fungicide applications after harvest will leave fewer chemical residues on fruits, thus decreasing negative impacts on human health. The defensin work has implications for better understanding male reproductive development, eventually perhaps leading to biotechnological applications.
Publications
- Cheng, V., Stotz, H. U., Hippchen, K. & Bakalinsky, A. T. Genome-wide screen for oxalate-sensitive mutants of Saccharomyces cerevisiae. Applied & Environmental Microbiology 73, 5919-5927 (2007).
- Guo, X. & Stotz, H. U. Defense against Sclerotinia sclerotiorum in Arabidopsis is dependent on jasmonic acid, salicylic acid, and ethylene signaling. Molecular Plant-Microbe Interactions 20, 1384-1395 (2007).
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Progress 01/01/06 to 12/31/06
Outputs
Title: Improvement of plant defenses against Botrytis cinerea Objective 1: Identification of gray mold resistance genes in tomato Expression of resistance is dominant in a F1 hybrid of a cross between tomato (Lycopersicon esculentum) and the nightshade Solanum lycopersicoides. Resistance of this nightshade to B. cinerea is based on induced fungal death. We have completed mapping of quantitative trait loci (QTL) for resistance to B. cinerea in an introgression line population derived from a cross between tomato and S. lycopersicoides. These introgression lines were derived from several generations of backcrosses. They contain chromosomal segments from the wild nightshade parent in the background of tomato. We have used spot inoculation of detached leaves to detect differences in gray mold resistance by measuring frequencies of lesion expansion, lesion diameters, and sporulation. We have identified quantitative trait loci (QTL) for resistance that lower infection
frequency on four different chromosomes. A resistance QTL slowing the rate of lesion expansion was found on another chromosome. Two susceptibility QTL were identified, one increasing infection frequency, the other accelerating lesion expansion. A susceptibility QTL and a resistance QTL have been verified by comparing phenotypes and markers in segregating progeny of a heterozygous parent. Additional resistance QTL will have to be analyzed to compare the magnitudes of each on resistance. The QTL with the largest effect can eventually be used for fine-mapping of the most important resistance locus. Objective 2: Analysis of gene expression during gray mold infection We previously reported on an acidic glucanase that was specifically induced in the resistant nightshade after infection with B. cinerea. The acidic glucanase gene does not map to any of the resistance QTL we have identified. Thus, it is more likely that transcriptional activation and not enzymatic activity is related to
Botrytis resistance. Objective 3: Contribution of antifungal compounds to gray mold resistance We have studied the contribution of a floral defensin to defense and reproductive development in transgenic tomato plants. Transgenic plants with elevated or reduced levels of defensin expression did not differ in susceptibility to B. cinerea from untransformed control plants. No antifungal activity could be isolated from plant extracts or bacterially expressed defensin, indicating that these types of defensins may not involved in defense. On the contrary, seed production and fruit size were reduced by overexpressing defensin. Fruit development was delayed as a result of defensin overexpression. It, thus, appears that floral defensins of tomato are involved in reproductive development and not in defense.
Impacts
The tomato lines we have identified as partially resistant to B. cinerea will be useful to seed companies and growers for development of improved germplasm. This fungus is difficult to control because it causes infections that remain dormant in the field and develop into fruit decay during post-harvest storage. Crop losses of up to 50% are not uncommon. Strategies for controlling Botrytis are limited by the emergence of strains that are resistant to one or several groups of fungicides. Most registered fungicides are protective in their action and will not control gray mold once the fungus is established, which limits effective control to pre-harvest applications of fungicides. Our long-term goal will remain isolation of genes that confer resistance to Botrytis. Because this fungus has a broad host range, these types of genes could be used to protect unrelated crop species against this fungus. Given the limited success of chemical fungicides, genetic improvement of
tomatoes is the most economical and environmentally appropriate strategy for disease control. In addition, reduction of the amount of fungicide applications after harvest will leave fewer chemical residues on fruits, thus decreasing negative impacts on human health.
Publications
- Cheng V., Stotz, H. U., Hippchen, K., and Bakalinsky, A. T. (2007) Genome-wide screen for oxalate-sensitive mutants of Saccharomyces cerevisiae. Applied & Environmental Microbiology (in review).
- Chipps TJ, Gilmore B, Myers JR, Stotz HU (2005) Relationship between oxalate, oxalate oxidase activity, oxalate sensitivity, and white mold susceptibility in Phaseolus coccineus. Phytopathology 95: 292-299
- Guimaraes RL, Stotz HU (2004) Oxalate production by Sclerotinia sclerotiorum deregulates guard cells during infection. Plant Physiol. 136: 3703-3711 Guimaraes, RL, Chetelat, RT, Stotz, HU (2004) Resistance to Botrytis cinerea in Solanum lycopersicoides is dominant in hybrids with tomato, and involves induced hyphal death. Europ. J. Plant Pathol. 110: 13-23.
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Progress 01/01/05 to 12/31/05
Outputs
Objective 1: Identification of gray mold resistance genes in tomato Our published results show that expression of resistance is dominant in a F1 hybrid of a cross between tomato (Lycopersicon esculentum) and the nightshade Solanum lycopersicoides. Resistance of this nightshade to B. cinerea is based on induced fungal death. We have completed mapping of quantitative trait loci (QTL) for resistance to B. cinerea in an introgression line population derived from a cross between tomato and S. lycopersicoides. These introgression lines were derived from several generations of backcrosses. They contain chromosomal segments from the wild nightshade parent in the background of tomato. We have used spot inoculation of detached leaves to detect differences in gray mold resistance by measuring frequencies of lesion expansion, lesion diameters, and sporulation. We have identified partial resistance to B. cinerea on four different chromosomes. We are now in the process of
determining the segregation of RFLP markers with partial resistance phenotypes. In addition, we have confirmed a QTL that confers susceptibility to B. cinerea, but additional segregating individuals will need to be analyzed to increase our confidence in this susceptibility locus. We expect that our mapping efforts will contribute to a better understanding of Botrytis resistance. Objective 2: Analysis of gene expression during gray mold infection In the past we have analyzed gene and protein expression changes in response to gray mold infection. Recently, we have become interested in the role of aspartic protease inhibitors (API) and their relationship to the oxidative burst. We have successfully amplified a putative API cDNA from wounded leaves of the nightshade S. lycopersicoides. Meanwhile we have monitored the production of reactive oxygen species (ROS) in the nightshade and tomato after inoculation with B. cinerea and observed significant differences between both species. In order
to analyze the contribution of this oxidative burst to disease resistance, we will utilize transgenic tomato plants that over-express enzymes involved in the turnover of ROS. Objective 3: Contribution of antifungal compounds to gray mold resistance We are studying the role of floral defensins, which are antimicrobial peptides, in transgenic tomato plants. Our preliminary data suggest that these peptides are involved in floral development. Sense and antisense transgenic tomato plants have been confirmed by genomic PCR and Southern hybridization. We are in the process of testing both mRNA and protein expression in order to correlate gene expression with phenotypic changes in fertility. Analysis of the contribution of defensins to disease resistance will depend on the segregation of transgenes in subsequent progeny generations.
Impacts
Botrytis has been listed as a reemerging pathogen of national importance in the year 2000. This fungus is difficult to control because it causes infections that remain dormant in the field and develop into fruit decay during post-harvest storage. Crop losses of up to 50% are not uncommon. Strategies for controlling Botrytis are limited by the emergence of strains that are resistant to one or several groups of fungicides. Most registered fungicides are protective in their action and will not control gray mold once the fungus is established, which limits effective control to pre-harvest applications of fungicides. Our primary goal is to generate plant material that is more resistant to Botrytis. As a consequence of these studies, we will be in a position to determine the feasibility of isolating genes that confer resistance to Botrytis. Because this fungus has a broad host range, these types of genes could be used to protect unrelated crop species against this fungus.
Given the limited success of chemical fungicides, genetic improvement of tomatoes is the most economical and environmentally appropriate strategy for disease control. In addition, reduction of the amount of fungicide applications after harvest will leave fewer chemical residues on fruits, thus decreasing negative impacts on human health.
Publications
- Chipps TJ, Gilmore B, Myers JR, Stotz HU (2005) Relationship between oxalate, oxalate oxidase activity, oxalate sensitivity, and white mold susceptibility in Phaseolus coccineus. Phytopathology 95: 292-299
- Guimaraes RL, Stotz HU (2004) Oxalate production by Sclerotinia sclerotiorum deregulates guard cells during infection. Plant Physiol. 136: 3703-3711
- Guimaraes, RL, Chetelat, RT, Stotz, HU (2004) Resistance to Botrytis cinerea in Solanum lycopersicoides is dominant in hybrids with tomato, and involves induced hyphal death. Europ. J. Plant Pathol. 110: 13-23
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Progress 01/01/04 to 12/31/04
Outputs
Objective 1: Identification of gray mold resistance genes in tomato Our published results show that expression of resistance is dominant in a F1 hybrid of a cross between tomato (Lycopersicon esculentum) and the nightshade Solanum lycopersicoides. Resistance of this nightshade to B. cinerea is based on induced fungal death. We have continued mapping of quantitative trait loci (QTL) for resistance to B. cinerea in an introgression line population derived from a cross between tomato and S. lycopersicoides. These introgression lines were derived from several generations of backcrosses. They contain chromosomal segments from the wild nightshade parent in the background of tomato. We have used spot inoculation of detached leaves to detect differences in gray mold resistance by measuring frequencies of lesion expansion, lesion diameters, and sporulation. We have completed mapping of Botrytis resistance for 10 of the 12 chromosomes. Chromosomes 2 and 8 still need to be fully
characterized. Two promising resistance QTL have been identified based on the fact that introgression lines with overlapping chromosomal segments share the resistance trait. In addition, we found evidence for a QTL that confers susceptibility to B. cinerea. We expect that our mapping efforts will contribute to a better understanding of Botrytis resistance. Objective 2: Analysis of protein expression during gray mold infection As a supplement of gene expression studies, we started analyzing protein expression in response to Botrytis infection. Pathogenesis-related and antimicrobial proteins are relatively tough and extractable under conditions that precipitate most other proteins. We therefore extracted proteins that are soluble in an acetic acid/ethanol mixture from leaves of S. lycopersicoides and L. esculentum that were challenged with B. cinerea or mock-inoculated. After SDS polyacrylamide gel electrophoresis, we identified two bands that were degraded only when tomato was
challenged with B. cinerea, but not when the nightshade was infected. The relationship between these two proteins and Botrytis infection will require their identification via mass spectrometry and a precise temporal and spatial analysis of their expression. Objective 3: Contribution of antifungal compounds to gray mold resistance In order to determine the possibility that plant metabolites influence the outcome of Botrytis infections, we extracted phytochemicals from leaves of tomato and S. lycopersicoides in methanol. We identified antifungal activity. A portion of this activity migrated at the same rate as alpha-tomatine, when separated on TLC with chloroform:methanol (95:5) and subsequently assayed with a conidial preparation of Cladosporium herbarum. The suggestive presence of antifungal glycoalkaloids may not be surprising. However, a substantial amount of antifungal activity was not eluted with chloroform:methanol (95:5). We still need to characterize these additional antifungal
compounds. There did not appear to be vast differences in the amount of antimicrobial activity between tomato and the nightshade irrespective of whether or not plants were inoculated with B. cinerea.
Impacts
Botrytis is difficult to control because it causes infections that remain dormant in the field and develop into fruit decay during post-harvest storage. Strategies for controlling Botrytis are limited by the emergence of strains that are resistant to one or several groups of fungicides. Since 2000, Botrytis has been listed as a reemerging pathogen of national importance. Most registered fungicides are protective in their action and will not control gray mold once the fungus is established, which limits effective control to pre-harvest applications of fungicides. Our primary goal is to generate plant material that is more resistant to Botrytis. As a consequence of these studies, we will be in a position to determine the feasibility of isolating genes that confer resistance to Botrytis. Because this fungus has a broad host range, these types of genes could be used to protect unrelated crop species against this fungus. Given the limited success of chemical fungicides,
genetic improvement of tomatoes is the most economical and environmentally appropriate strategy for disease control. In addition, reduction of the amount of fungicide applications after harvest will leave fewer chemical residues on fruits, thus decreasing negative impacts on human health.
Publications
- Guimaraes RL, Chetelat RT, Stotz HU (2004) Resistance to Botrytis cinerea in Solanum lycopersicoides is dominant in hybrids with tomato, and involves induced hyphal death. European Journal of Plant Pathology 110: 13-23
- Guimaraes RL, Stotz HU (2004) Oxalate production by Sclerotinia sclerotiorum deregulates guard cells during infection. Plant Physiology 136: 3703-3711
- Stotz HU, Elad Y, Powell ALT, Labavitch JM (2004) Innovative biological approaches to Botrytis suppression. In Botrytis: Biology, Pathology and Control, Y Elad, B Williamson, P Tudzynski, N Delen, eds. Kluwer Academic Publishers, Dordrecht, pp 369-392
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Progress 01/01/03 to 12/31/03
Outputs
Objective 1: Identification of gray mold resistance genes in tomato We have initiated mapping of quantitative trait loci for resistance to Botrytis in an introgression line population derived from a cross between tomato (Lycopersicon esculentum) and Solanum lycopersicoides. These lines were derived from several generations of backcrosses. They contain chromosomal segments from the wild nightshade parent in the background of tomato. We use spot inoculation of detached leaves to detect differences in gray mold resistance. We have completed 23% of the S. lycopersicoides introgression lines and identified several quantitative trait loci of small effect that alter the interaction with Botrytis. We expect that our mapping efforts will contribute to a mechanistic understanding of Botrytis resistance. We also compared the resistance of tomato and L. cheesmanii and identified significant differences. This provides us with additional opportunities because recombinant inbred
lines are available for mapping of Botrytis resistance. Objective 2: Analysis of gene expression during gray mold infection of tomato We tested the expression of 5 different pathogenesis-related genes for differences in expression in response to Botrytis infection. A beta-(1,3)-glucanase was transiently induced during incompatible interactions with S. lycopersicoides prior to the onset of fungal death. This finding suggested that beta-(1,3)-glucanase is involved in resistance to Botrytis. However, this gene maps to the top arm of chromosome 1, a region that does not contain resistance to Botrytis based on analysis of introgression lines containing a chromosomal segment covering this region from S. lycopersicoides in the background of cultivated tomato. We will continue to analyze gene expression at a larger scale using tomato microarrays. Combination of gene expression profiling and resistance screening provides novel opportunities to dissect the mechanisms of gray mold resistance.
Objective 3: Contribution of antifungal compounds to gray mold resistance We have not yet succeeded in identifying antifungal activities from leaf extracts. As an alternative, we are currently testing the contribution of reactive oxygen species to interactions between Botrytis and tomato. Preliminary data suggest that reactive oxygen species may protect against Botrytis infection. This is based on chemical treatments of leaves that promote the generation of reactive oxygen species in situ. We will need to determine whether reactive oxygen species act as a signal or are directly toxic to the fungus.
Impacts
Botrytis cinerea, the causal agent of gray mold, is a widespread pathogen that causes substantial economic losses of fruits, vegetables, and flowers during their production and after harvest. Gray mold is a significant and persistent disease problem of greenhouse and field grown tomato (Lycopersicon esculentum) plants. Botrytis can limit field production of tomato in cool and humid climates. Gray mold is a more common disease problem of greenhouse grown tomatoes. This disease is one of the main causes of post-harvest decay of fresh market tomatoes, and it occasionally reduces yields of processing tomatoes when harvest is preceded by rain, heavy dew, or fog. Botrytis is difficult to control because it causes infections that remain dormant in the field and develop into fruit decay during post-harvest storage. Strategies for controlling Botrytis are limited by the emergence of strains that are resistant to one or several groups of fungicides. Since 2000, Botrytis has
been listed as a reemerging pathogen of national importance. Most registered fungicides are protective in their action and will not control gray mold once the fungus is established, which limits effective control to pre-harvest applications of fungicides. Given the limited success of chemical fungicides, genetic improvement of tomatoes is the most economical and environmentally appropriate strategy for disease control. In addition, reduction of the amount of fungicide applications after harvest will leave fewer chemical residues on fruits, thus decreasing negative impacts on human health.
Publications
- No publications reported this period
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Progress 01/01/02 to 12/31/02
Outputs
Objective 1. We have shown that S. lycopersicoides is more resistant to B. cinerea than cultivated tomato. Spot inoculation of detached leaves and spray inoculation of intact seedlings provided statistically significant differences in gray mold resistance between S. lycopersicoides (LA2951) and L. esculentum cv. 'VF36'. In addition, S. lycopersicoides species varied in resistance to B. cinerea. L. chilense and L. cheesmanii were more resistant than cultivated tomato and are promising species for enhancement of gray mold resistance in tomato. Resistance to B. cinerea is expressed as a dominant trait because spore production of B. cinerea in leaves of S. lycopersicoides and an intergeneric hybrid was approximately 40 and 160 times less than in tomato leaves, respectively. There were no significant differences of sporulation in leaves of S. lycopersicoides and the intergeneric hybrid. Objective 2. Prior to analysis of gene expression, we had to obtain information about
the infection process in resistant S. lycopersicoides and susceptible tomato plants. For this purpose, we used a green fluorescent protein-tagged B. cinerea strain. This strain grew and developed in tomato leaves similarly to other non-tagged B. cinerea isolates. During the first 2 days, there were no significant differences in the percentage of spore germination or hyphal growth between S. lycopersicoides and L. esculentum. However, S. lycopersicoides caused disruption of fungal growth and hyphal lysis after 3 days. At the same time, B. cinerea accelerated its growth rate on susceptible tomato plants. Fungal death probably explains why S. lycopersicoides prevented fungal spread, resulting in a drastic decrease in sporulation. Objective 3. We have collected apoplastic fluids from leaves of S. lycopersicoides and L. esculentum challenged with B. cinerea, resulting in a yield of 500 ul of fluid containing 10 to 50 ug of protein per leaf. Peptides were analyzed using matrix-assisted
laser desorbtion/ionization time-of-flight (MALDI-TOF). Preliminary data suggest that apoplastic fluids collected from a single leaf are enough for MALDI-TOF analysis. Infected and uninfected tomato leaves differed in a number of peaks. We have developed antifungal assays. Conidia of B. cinerea were generated and incubated in half-strength potato dextrose broth (PDB). A volume of 25 ul of this spore suspension was applied to microtiter dishes and combined with an equal volume of concentrated apoplastic fluids resuspended in half-strength PDB. As a positive control, magainin (American Peptide Company) was used at a final concentration of 50 ug/ml. This is the minimal concentration of magainin that inhibits B. cinerea spore germination and hyphal growth. Apoplastic fluids (40% of the amount of a single leaf) did not interfere with hyphal growth of B. cinerea.
Impacts
The coordinated temporal regulation of plant and fungal genes will provide clues to which signaling pathways might be involved in plant defense and fungal virulence, respectively. We predict that this study will provide novel strategies to manage gray mold diseases in tomato and other crop species.
Publications
- No publications reported this period
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Progress 01/01/01 to 12/31/01
Outputs
Objective 1. Identification and characterization of gray mold resistance genes in tomato. The natural resource of wild tomato relatives has not yet been exploited to introduce gray mold resistance into commercial cultivars, even though Solanum lycopersicoides has been reported to be more resistant to Botrytis stem infections than cultivated tomato. A mapping population of a cross between L. esculentum and S. lycopersicoides is available to locate the genetic loci responsible for gray mold resistance. Experiments are under way to compare the resistance of leaves and intact seedlings among L. esculentum and S. lycopersicoides. Objective 2. Analysis of gene expression during gray mold infection of tomato. Synchronization of gray mold infection permits simultaneous analyses of fungal and plant gene expression in tomato leaves. Once the conditions for synchronized infection have been optimized, we will study the expression of fungal virulence. These initial experiments
will set the stage for more comprehensive expression assays using tomato and B. cinerea microarrays. Objective 3. Contribution of antifungal compounds to gray mold resistance. Plants produce molecules that inhibit in vitro fungal growth and some of these even protect against fungal infection. In order to learn more about these defense systems, we will initially focus our attention on antimicrobial defensin peptides in tomato.
Impacts
The coordinated temporal regulation of plant and fungal genes will provide clues to which signaling pathways might be involved in plant defense and fungal virulence, respectively. We predict that this study will provide novel strategies to manage gray mold diseases in tomato and other crop species.
Publications
- No publications reported this period
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Progress 01/01/94 to 12/30/94
Outputs
ORE00374 Hazelnut postharvest quality evaluations included effects of drying regimes, roasting temperatures, and durations on pellicle sloughing, oil oxidative stability, peroxide values, tocopherol degradation, and taste panel perceptions of roast aroma and flavor intensity and off-aroma/flavor. Field temperature monitoring of commercial drying regimes were surprisingly uniform in not using excessively high temperatures. Although rates of drying differed due to air velocity, air exchanges, and flow design, all operations achieved 6% kernel moisture with minor differences in quality. Pellicle loosening and removal upon roasting for more than 20 minutes at 121deg.C was generally satisfactory, although pellicle adhesion is highly variety-dependent. Roast flavor requires at least 20 minutes and oven temperatures of 135deg.C, with best roasting flavors about 160deg.C for 30 minutes. Higher roasting temperatures, however, decreased vitamin E by nearly 20% in the first week
after roasting and slightly increased peroxide values (PV = 0.8 to 0.9), but 6 months after roasting, PV rose to 20, with a 50% loss of vitamin E. Pear scald: Further comparisons of two new anti-scald materials (patent applied for) showed good scald control of several cultivars of apple and pear. Pear flavor volatiles: Experiments are complete quantifying and identifying 8 major pear variety volatile development during storage and ripening. Alcohol acyl transferase enzymatic activity has also been characterized. Broccoli map stora.
Impacts
(N/A)
Publications
- RICHARDSON, D. G. and KOSITTRAKUN, M. 1995. Off-flavor development of apples, pears, berries, and plums under anaerobiosis and partial reversal in air. In: Advances in Fruit Flavors (Leahy, M. and R. Rouseff, eds.). Chapter 19. Amer. Chem.
- SANZ, C., PEREZ, A. G., and RICHARDSON, D. G. 1995. 2,5-dimethyl-4-hydroxy-3(2H)-furanone and derivatives content in strawberries during ripening. In: Advances in Fruit Flavors (Leahy, M. and R. Rouseff, eds.).Chapter 24. Amer. Chem. Soc.
- SANZ, C., PEREZ, A. G., and RICHARDSON, D. G. 1994. Simultaneous HPLC determination of 2,5-dimethyl-4-hydroxy-3(2H)-furanone and related strawberry flavor compounds. J. Food Sci. 59:139-141.
- CHANTRACHIT, T. 1994. Banana quality: Flavor volatiles under anaerobic and aerobic conditions. M.S. thesis. Oregon State University. 158 pp.
- ZOFFOLI, J. P. 1994. Pear fruit scald: A physiologic disorder involving a-farnesene, conjugated trienes and a-tocopherol. MS thesis. Oregon State University. 157 pp.
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