Impact of water heat treatment on physical-chemical, biochemical and microbiological quality of whole tomato (Solanum lycopersicum) fruit

J. Pinheiro*, C. L. M. Silva, C. Alegria, M. Abreu, M. Sol, E. M. Gonçalves

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

4 Citations (Scopus)

Abstract

Water heat treatments (WHT) are applied to fresh fruits for disinfection purposes as well as to promote changes to the biochemical pathways involved in the ripening process, resulting in remarkable beneficial effects on postharvest quality maintenance and storage life extension. The objective of this study was to evaluate the overall effects of WHT on tomato (Solanum lycopersicum 'Zinac') quality and to determine an optimal WHT condition to extend its shelf-life. Fruits were immersed in hot water at different temperatures (from 40 to 60°C) and during different periods of time (2 to 60 min). WHT effects on fruit colour CIELab parameters (a* and °h), firmness (N), peroxidase (POD) and pectinmethylesterase (PME) enzyme activity, total phenolic content (TPC) and microbial load (mesophylic and yeasts & moulds counts (Y&M)) were evaluated. After WHT no observable color changes were denoted in all heat treated samples. At lower WHT, 40-50°C, maintenance in firmness was obtained when compared to untreated samples. Significant reductions on tomato firmness were observed in treatments with temperatures higher than 55°C. Both evaluated enzymatic activities were affected by the heat treatments. Regarding POD enzyme, an increase in its activity was found with intensive WHT, while PME activity decreased at all tested conditions with two exceptions (45 and 60°C). In fruits treated at 40°C/30 min the highest increase in TPC was found when compared to the control sample (ca. 27%). WHT at 50°C/2 min or 40°C/30 min promoted a reduction in mesophylic and Y&M load to undetectable levels, showing the effectiveness of these treatments to control microbial development in tomato fruits. Therefore, these treatments present an alternative postharvest process for tomato storage with beneficial effects to fruit quality as well as extension of shelf life.
Original languageEnglish
Title of host publicationXXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010)
Subtitle of host publicationInternational Symposium on Postharvest Technology in the Global Market
PublisherInternational Society for Horticultural Science
Pages1269-1276
Number of pages8
ISBN (Print)9789066053786
DOIs
Publication statusPublished - 30 Jun 2012
EventXXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Postharvest Technology in the Global Market - Lisboa, Portugal
Duration: 22 Aug 201027 Aug 2010
Conference number: 28

Publication series

NameActa Horticulturae
Volume934
ISSN (Print)0567-7572

Conference

ConferenceXXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010)
Country/TerritoryPortugal
CityLisboa
Period22/08/1027/08/10

Keywords

  • Colour
  • Enzymatic activity
  • Firmness
  • Mature-green tomato
  • Microbial load
  • Phenolic compounds

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