Submitted to: World Congress of Food Science and Technology
Publication Type: Abstract Only
Publication Acceptance Date: September 23, 2008
Publication Date: October 18, 2008
Citation: Kou, L., Luo, Y., Liu, X. 2008. Combination of hot water and rachis removal as an alternative to chemical treatment for maintaining the quality of table grapes. World Congress of Food Science and Technology.
Decay and rachis browning are major problems that limit the shelf life of fresh table grapes (Vitis vinifera cv. Crismons seedless) and are often controlled by application of sulfur dioxide (SO2) to maintain quality. However, sulphite residues pose a health risk for allergic individuals and SO2 applications have consequently been restricted in many countries. The main objective of this study was to evaluate the use of mild heat treatment, rachis removal, sanitizing pre-wash and modified atmosphere package (MAP) to maintain quality and extend shelf-life of table grapes. Fresh seedless grapes were prepared by cutting off the pedicels 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 weeks for quality evaluation. Gas composition, texture, decay, sensory evaluation and microbial growth of cut and cluster grapes were evaluated. Results indicated that hot water treatment of grapes significantly affected package atmospheres, maintained a firmer texture, higher overall quality, lower decay rate and lower microbial population than other treatments or the control during entire storage periods. Cut grapes treated with hot water maintained the highest quality for 4 weeks with the least decay among all treatments. A chlorine pre-wash treatment significantly reduced microbial populations and maintained better overall quality. Commercially packaged grapes developed dark decay and became unacceptable at the end of storage.