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Effect of high hydrostatic pressure on microbial load and quality parameters of grape juice
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Date
2010
Author
Mert, Mecnun
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Effect of high hydrostatic pressure (150-200-250 MPa) on the microbial load and quality parameters (pH, color, 5-hydroxymethylfurfural-HMF) of white (Sultaniye) and red (Alicante Bouschet) grape juices with combination of temperature (20-30-40°C) and holding time (5-10-15 min) was studied. Increased pressure and temperature showed significant effect on microbial reduction in white and red grape juices (p<0.05). The effect of pressure and time on pH drop was found to be insignificant (p>0.05). HHP resulted in E<1 for white grape and E<7 for red grape juice samples. Shelf life analysis for HHP treated white grape juice (200 MPa-40°C-10min) and red grape juice (250 MPa-40°C-10min) revealed no microbial growth up to 90 days when stored at 25°C. Although HMF formation was observed in industrially manufactured, pasteurized samples (65°C for 30 min), no HMF was detected in HHP treated white and red grape juices. HHP at the suggested conditions can be recommended as a better production alternative to heat treatment for white and red grape juice with respect to microbial load and studied quality parameters even at temperatures lower than required for pasteurization.
Subject Keywords
Food engineering.
,
QR Microbiology 1-502
URI
http://etd.lib.metu.edu.tr/upload/12611536/index.pdf
https://hdl.handle.net/11511/19396
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Graduate School of Natural and Applied Sciences, Thesis
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M. Mert, “Effect of high hydrostatic pressure on microbial load and quality parameters of grape juice,” M.S. - Master of Science, Middle East Technical University, 2010.
