Key tomato volatile compounds during postharvest ripening in response to chilling and pre-chilling heat treatments

Authors: WANG, LIBIN - Nanjing Agricultural University; Baldwin, Elizabeth - Liz; LUO, WEIQI - North Carolina State University; ZHAO, WEI - Former ARS Employee; BRECHT, JEFF - University Of Florida; Bai, Jinhe

Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/2019
Publication Date: 5/1/2019
Citation: Wang, L., Baldwin, E.A., Luo, W., Zhao, W., Brecht, J., Bai, J. 2019. Key tomato volatile compounds during postharvest ripening in response to chilling and pre-chilling heat treatments. Postharvest Biology and Technology. https://doi.org/10.1016/j.postharvbio.2019.04.013.
DOI: https://doi.org/10.1016/j.postharvbio.2019.04.013

Interpretive Summary: Although being consumed when at red stage, tomatoes are usually harvested at the mature green or breaker stage in order to prolong storage and marketing life and to minimize postharvest losses. To enhance the storibility, fruit are frequently stored at low temperature. This research demonstrated that, even a short exposure to a mild low temperature and without visual chilling injury on fruit, flavor quality was markedly affected. A hot water treatment before low temperature storage alleviated chilling caused flavor loss. This report also traced the volatile changes during the entire ripening and storage/marketing periods.

Technical Abstract: Mature green ‘FL 47’ tomatoes were exposed to heat (52 °C water for 5 min) and/or cold (5 °C for 4 d), and the subsequent volatile production during ripening at 20 °C was determined. Fruit were sampled initially after each treatment, then at breaker, turning, pink, and red stages. Results showed that although chilling and heating did not cause visual injury, chilling substantially slowed the ripening process, and suppressed ethylene production and respiration rate at each stage during ripening. Heating, conversely, only mildly affected ripening, respiration and ethylene production. Most volatiles were detected at low levels before breaker stage, increased significantly at pink, but did not peak until the full red ripe stage in all treatments. Chilling and heating induced production of “green” note volatiles, especially cis-3- and trans-2-hexenal early in fruit development. When fruit reached the full red stage, 11 out of 12 important aromatic volatiles exhibited significant reduction in the chilled fruit compared to untreated controls. Although heating accelerated the ripening process, it had less impact on volatile production at the red stage. Heating prior to cold storage alleviated the chilling-caused reduction of ethylene during ripening, which was associated with higher levels of 6-methyl-5-hepten-2-one, 2-phenylacetaldehyde, and 2-phenylethanol in red fruit.