Progress 10/01/08 to 09/30/13
Outputs Target Audience: This research is presented annually during extension courses offered by the Postharvest Technology Research and Information Center (Postharvest technology Short Course, Fresh-cut Workshop, Fruit Ripening Workshop). These workshops are designed for quality control personnel and professionals involved in the fresh produce industry and postharvest technology, and for research and extension workers. The results obtained through this project have immediate applications for postharvest programs aimed at maintaining superior quality of produce. The improvement of fruit flavor will benefit California agriculture through the delivery to consumers of higher quality crops which will be more competitive in the global food market. Moreover, the creation of better tasting produce could also have a positive impact on consumers' dietary choices by increasing acceptance of fruits and vegetables. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? This project has provided opportunities to train undergraduate and graduate students, as well as postdoctoral researchers, on a wide range of scientific approaches (biology, biochemistry and analytical chemistry). Three undergraduate students (Elise Croda, Sharon Wei and Khan Hien Tran), two graduate students (Elenor Castillo and Anna Hjelmeland), one laboratory research volunteer (Siranoosh Ashtari), one Postdoctoral Associate (Simona Vallone) were involved in the project. This work included collaborative relationships with Dr. Marita Cantwell who provided expertise on melon storage and 1-MCP application and dosage, and with AgroFresh, a key player in the postharvest industry. How have the results been disseminated to communities of interest? This research is presented annually during extension courses offered by the Postharvest Technology Research and Information Center (Postharvest technology Short Course, Fresh-cut Workshop, Fruit Ripening Workshop, Delivering More Flavorful Produce Workshop). These workshops are designed for quality control personnel and professionals involved in the fresh produce industry and postharvest technology, and for research and extension workers. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts What was accomplished under these goals?
We have demonstrated the ability of an electronic nose to discriminate between different maturity levels of melon fruits, and between different varieties of melons. We also found volatile markers as candidates for maturity indicators. We have shown the impact of 1-MCP treatment on the aroma production of apricots and melons. We have also related these changes to sensory perception of flavor using descriptive analysis. These studies can inform commercial postharvest practices for these fruits in the future. We have tested the effect of maturity at harvest and cultivar (genetics) on the sensory quality of melon. Physiochemical quality parameters such as Soluble Solids Content, Acidity, Texture measurements, and aroma volatile profile were assessed initially and after a period of 2-week storage. In parallel, a sensory descriptive panel evaluated the flavor of the melons from different treatments. Our results have uncovered interesting correlations between fruit composition and human sensory perception of flavor. For example, the concentration of certain volatile compounds, but unexpectedly, not sugar content, was correlated with sweetness perception. In addition, we found intriguing correlations between sweetness perception and the levels of glutamate, an essential amino acid. Our findings have important implications for the development of fruits with increased sweetness, and therefore, better consumer acceptance.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Vallone S, Lloyd NW, Ebeler SE, Zakharov F (2012). Fruit Volatile Analysis Using an Electronic Nose. J Vis Exp, e3821
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Vallone S, Sivertsen H, Anthon GE, Barrett DM, Mitcham EJ, Ebeler SE, Zakharov F (2013). An integrated approach for flavor quality evaluation in muskmelon (Cucumis melo L. reticulatus group) during ripening. Food Chemistry 139: 171-183
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Progress 01/01/12 to 12/31/12
Outputs OUTPUTS: We are using physiological and molecular biological approaches to understand flavor development and the impact of postharvest handling on aroma. We have tested an electronic nose (the zNose, EST, Newbury Park CA) for its ability to rapidly evaluate produce quality. Its performance has been tested as compared to reference methods for maturity and flavor assessment such as standard quality measurements (soluble solids content, firmness, sensory quality). We have presented our results at extension courses offered by the UC Davis Postharvest Technology Research and Information Center (Postharvest technology Short Course, Fresh-cut Workshop, Fruit Ripening Workshop, Delivering More Flavorful Produce Workshop) and at scientific meetings, including the workshop on "fruit flavor" at the 2012 ASHS meeting (Miami, FL). PARTICIPANTS: One Postdoctoral Associate (Simona Vallone) and one undergraduate student intern (Sharon Wei) were involved in the project this year. TARGET AUDIENCES: This research is presented annually during extension courses offered by the Postharvest Technology Research and Information Center (Postharvest technology Short Course, Fresh-cut Workshop, Fruit Ripening Workshop, Delivering More Flavorful Produce Workshop). These workshops are designed for quality control personnel and professionals involved in the fresh produce industry and postharvest technology, and for research and extension workers. The results obtained through this project have immediate applications for postharvest programs aimed at maintaining superior quality of produce. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts We have tested the effect of maturity, cultivar (genetics) and the effect of 1-MCP treatment in combination with high-temperature storage (15C) on the sensory quality of melon (cantaloupe and honeydew). Physiochemical quality parameters such as Soluble Solids Content, Acidity, Texture measurements, and aroma volatile profile were assessed initially and after a period of 2-week storage. In parallel, a sensory descriptive panel evaluated the flavor of the melons from different treatments. Our results have also uncovered interesting correlations between fruit composition and human sensory perception of flavor. For example, the concentration of certain volatile compounds, but unexpectedly, not sugar content, was correlated with sweetness perception. In addition, we found intriguing correlations between sweetness perception and the levels of glutamate, an essential amino acid. Our findings have important implications for the development of fruits with increased sweetness, and therefore, better consumer acceptance. We have demonstrated the ability of an electronic nose to discriminate between different maturity levels of melon fruits, and found volatile markers as candidates for maturity indicators and for sensory characteristics.
Publications
- Vallone S, Lloyd NW, Ebeler SE, Zakharov F (2012). Fruit Volatile Analysis Using an Electronic Nose. J Vis Exp, e3821.
- Vallone S, Sivertsen H, Anthon GE, Barrett DM, Mitcham EJ, Ebeler SE, Zakharov F (2013). An integrated approach for flavor quality evaluation in muskmelon (Cucumis melo L. reticulatus group) during ripening. Food Chemistry http://dx.doi.org/10.1016/j.foodchem.2012.12.042
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Progress 01/01/11 to 12/31/11
Outputs OUTPUTS: This project investigates the effects of genetics, maturity at harvest, cold storage and 1-MCP on the expression of aroma-forming genes and on volatile production in fruits. We are taking physiological and molecular biological approaches to understand flavor development and the impact of postharvest handling on aroma. We are also testing an electronic nose (the zNose, EST, Newbury Park CA) which shows potential for rapid evaluation of produce quality. Its performance has been tested as compared to reference methods for maturity and flavor assessment. We have presented our results at extension courses offered by the UC Davis Postharvest Technology Research and Information Center (Postharvest technology Short Course, Fresh-cut Workshop, Fruit Ripening Workshop, Delivering More Flavorful Produce Workshop) and at scientific meetings, including the 2012 Gordon Research Conference on Plant Volatiles PARTICIPANTS: One Postdoctoral Associate (Simona Vallone) and two undergraduate student interns (Sharon Wei and Khan Hien Tran) were involved in the project this year. This work includes collaborative relationships with Dr. Marita Cantwell who provided expertise on melon storage and 1-MCP application and dosage. TARGET AUDIENCES: This research is presented annually during extension courses offered by the Postharvest Technology Research and Information Center (Postharvest technology Short Course, Fresh-cut Workshop, Fruit Ripening Workshop, Delivering More Flavorful Produce Workshop). These workshops are designed for quality control personnel and professionals involved in the fresh produce industry and postharvest technology, and for research and extension workers. The results obtained through this project have immediate applications for postharvest programs aimed at maintaining superior quality of produce. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts We have tested the effect of 1-MCP treatment in combination with high-temperature storage (15C) on the sensory quality of melon (cantaloupe and honeydew). Physiochemical quality parameters such as Soluble Solids Content, Acidity, Texture measurements, and aroma volatile profile were assessed initially and after a period of 2-week storage. In parallel, a sensory descriptive panel evaluated the flavor of the melons from different treatments. We are still in the process of analyzing the results. We have demonstrated the ability of an electronic nose to discriminate between different maturity levels of melon fruits, and found volatile markers as candidates for maturity indicators and for sensory characteristics.
Publications
- No publications reported this period
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Progress 01/01/10 to 12/31/10
Outputs OUTPUTS: This project investigates the effects of genetics, maturity at harvest, cold storage and 1-MCP on the expression of aroma-forming genes and on volatile production in fruits. We are taking physiological and molecular biological approaches to understand flavor development in apricot and the impact of postharvest handling on apricot aroma. This year we investigated the genes involved in the formation of norisoprenoid compounds, which are derived from carotenoid pigments. The presence of white-fleshed apricot cultivars allows us to investigate the effect of carotenoid content on the aroma profile of these fruits. We are testing an electronic nose (the zNose, EST, Newbury Park CA) which shows potential for rapid evaluation of produce quality. The zNose is a fast GC system which uses a surface acoustic wave (SAW) sensor as the detector. Its performance has been tested as compared to reference methods for maturity and flavor assessment. If this technology proves accurate and robust, it will also be tested in commercial settings at several levels of the supply chain, in collaboration with our industry partners. PARTICIPANTS: One laboratory research volunteer (Siranoosh Ashtari), one Postdoctoral Associate (Simona Vallone) and one undergraduate student intern (Elise Croda) were involved in the project this year. This work includes collaborative relationships with a key player in Postharvest industry: Agrofresh. Dr. Deirdre Holcroft of Agrofresh provides expertise on 1-MCP application and dosage. These projects are multidisciplinary in nature, combining molecular biology, biochemistry and analytical chemistry to gain a better understanding of the processes involved in aroma formation after harvest. This program therefore exposes students to a wide range of scientific approaches which will be useful in their future career. TARGET AUDIENCES: This research is presented annually during extension courses offered by the Postharvest Technology Research and Information Center (Postharvest technology Short Course, Fresh-cut Workshop, Fruit Ripening Workshop, Delivering More Flavorful Produce Workshop). These workshops are designed for quality control personnel and professionals involved in the fresh produce industry and postharvest technology, and for research and extension workers. The results obtained through this project have immediate applications for postharvest programs aimed at maintaining superior quality of produce. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts Storage of apricots at 0C for one week (followed by a 2-day ripening period at 20C) reduced total volatile production by ~70% (compared to the total volatile output at harvest). The emission of all volatiles recovered in this study decreased following one week of storage. The production of the monoterpene linalool, the most abundant volatile compound at the time of harvest, completely ceased after cold storage. One further week of storage resulted in a further reduction of the production of most volatiles detected at harvest, with the notable exception of ethyl butanoate and ethyl hexanoate, which were not detected at harvest but were recovered in the headspace of apricots stored for 2 weeks at 0C. These ethyl esters may indicate the onset of fermentative metabolism in the fruits, as they are derived from ethanol. Treatment with 1-MCP drastically reduced the amount of volatiles recovered from the apricots. After one week in storage at 0C, the total volatile output was reduced by ~77% when compared to fruits stored at 0C for 1 week but not treated with 1-MCP. One more week of storage did not markedly alter the total volatile production; however the volatile ester butyl butanoate could not be recovered in the headspace. Treatment with 1-MCP prevented the appearance of ethyl esters, indicating that 1-MCP may prevent the onset of fermentative metabolism in apricots during storage. We have demonstrated the ability of an electronic nose to discriminate between different maturity levels of melon fruits, and found volatile markers as candidates for maturity indicators. We continue to explore the relationships between instrumental and sensory analyses in collaboration with flavor chemists and sensory scientists.
Publications
- No publications reported this period
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Progress 01/01/09 to 12/31/09
Outputs OUTPUTS: Apricots, like many other stone fruits, are generally harvested at an early stage of maturity (pre-climacteric) to avoid bruising or water loss during postharvest handling. While this maintains a good appearance quality of the fruit, apricots harvested too early and ripened after harvest may not develop satisfactory flavor quality. In this ongoing project, we are evaluating the effects of maturity at harvest, cold storage and 1-MCP treatment on the expression of aroma-forming genes and on volatile production in two apricot cultivars, Robada and Blenheim. The aroma of apricots is a complex mixture of over 80 volatile compounds, including terpenoids, esters, lactones and fatty acid derivatives. Esters are a ubiquitous class of aroma compounds present in many fruits. They arise from the esterification of alcohols and acyl-CoAs in a reaction catalyzed by alcohol acyl transferases (AATs). Volatile norisoprenoids (like beta-ionone and beta-damascenone) also contribute significantly to the aroma of apricots. These compounds have extremely low odor thresholds (on the order of a few ppb) and arise from the oxidative breakdown of carotenoids (beta-carotene, lutein, zeaxanthin) in a reaction catalyzed by Carotenoid Cleavage Dioxygenases (CCDs). Apricots (cv. Robada, an early cultivar, and cv. Blenheim, later maturing) were harvested at commercial maturity and at a later maturity stage. Fruit were stored at 0C or 10C, with or without a prior 1-MCP treatment (500 ppb, 12h, 10C) for 1 week and 2 weeks. After storage, fruits were allowed to ripen at 20C for 2 days before quality measurements were taken. Apricots were evaluated for Soluble Solids Content (SSC), Titratable Acidity (TA), firmness, color, ethylene and CO2 production rates, and aroma volatile emission (using dynamic headspace and GC-MS) at harvest and after storage. The expression of aroma biosynthetic genes is currently being determined at harvest and after storage. The results of this research are being presented yearly at the NE-1036 meeting. PARTICIPANTS: Two graduate students, Elenor Castillo (Plant Biology Graduate Group) and Anna Hjelmeland (Agricultural Chemistry Graduate Group) were involved in this project. This work includes collaborative relationships with a key player in Postharvest industry: Agrofresh. Dr. Deirdre Holcroft of Agrofresh provides expertise on 1-MCP application and dosage. These projects are multidisciplinary in nature, combining molecular biology, biochemistry and analytical chemistry to gain a better understanding of the processes involved in aroma formation after harvest. This program therefore exposes graduate students to a wide range of scientific approaches which will be useful in their future career. TARGET AUDIENCES: This research is presented annually during extension courses offered by the Postharvest Technology Research and Information Center (Postharvest technology Short Course, Fresh-cut Workshop, Fruit Ripening Workshop). These workshops are designed for quality control personnel and professionals involved in the fresh produce industry and postharvest technology, and for research and extension workers. The results obtained through this project have immediate applications for postharvest programs aimed at maintaining superior quality of produce. The improvement of fruit flavor will benefit California agriculture through the delivery to consumers of higher quality crops which will be more competitive in the global food market. Moreover, the creation of better tasting produce could also have a positive impact on consumers' dietary choices by increasing acceptance of fruits and vegetables. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts We have cloned apricot AAT and CCD genes in mature fruits and will investigate the formation of esters and norisoprenoids during postharvest storage. We have determined the developmental changes in aroma profile of apricot fruits from immature to mature fruit, and identified over 80 volatile compounds in this profile. Our results on apricot cultivar Robada indicate that 1-MCP treatment appeared to be generally more effective at retaining firmness for more mature ("Stage 4") apricots compared to commercially mature ("Stage 3") fruit. For both stages, the effect of 1-MCP was more pronounced at 10C than at 0C. Fruits harvested at a later maturity level (Stage 4) developed higher SSC after storage, regardless of the treatment. Expression profiling experiments are still underway.
Publications
- No publications reported this period
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