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Title: Developing an Alternative to Sulfur Dioxide for Maintaining Quality and Reducing Decay of Table Grapes during Storage

Author
item KOU, LIPING - NORTHWEST A&F UNIV,CHINA
item Luo, Yaguang - Sunny

Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 3/26/2007
Publication Date: 4/25/2007
Citation: Kou, L., Luo, Y. 2007. Developing an Alternative to Sulfur Dioxide for Maintaining Quality and Reducing Decay of Table Grapes during Storage. BARC Poster Day.

Interpretive Summary:

Technical Abstract: Decay and rachis browning are major problems that limit the shelf life of fresh table grapes (Vitis vinifera L.) and are often controlled by the application of sulfur dioxide (SO2) to maintain quality. However, SO2 is dangerous to people who are allergic to sulfites and its application has been restricted in many countries. The main objective of this study was to develop an alternative to SO2 for maintaining quality and shelf-life of table grapes using a combination of rachis removal, mild heat treatment, a sanitized wash, and modified atmosphere packaging (MAP) technologies. Fresh seedless and seeded table grapes were prepared by cutting off the capstems 1-2 mm from the fruit, followed by a sanitizing wash and a hot water treatment (45°C, 8 min). The grapes were drained, cooled and packaged in containers sealed with a special gas permeable film. The packages were stored at 5°C for up to four months for quality evaluation. Results indicated that rachis removal by cutting the capstems close to the fruit significantly reduced decay development over those retaining the rachis. Hot water treatment further reduced decay and maintained grape quality during storage. Washing with chlorinated water prior to the hot water treatment reduced lactic acid bacterial and aerobic bacterial populations. Samples that received the combination treatment maintained acceptable quality for up to 4 months, while the control developed severe decay and became unacceptable within one month. This method for preparing grapes provides a much needed alternative to the current chemical sulfur dioxide treatment, and allows US grape export to expand to countries where SO2 treatment is prohibited. This new technology benefits consumers by providing clean and wholesome fresh produce and growers by providing a pesticide-free method prolonging grape storage with reduced shipping costs.