Effect of high hydrostatic pressure on microbial load and quality parameters of grape juice

Download
2010
Mert, Mecnun
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.

Suggestions

Effects of high hydrostatic pressure on shelf life of lager beer
BUZRUL, S; Alpas, Hami; BOZOGLU, F (Springer Science and Business Media LLC, 2005-05-01)
Filtered bright lager beer samples were either treated with high hydrostatic pressure (HHP, 350 MPa for 3 and 5 min at 20 C) or conventional heat pasteurization (60 C for 15 min). A storage period of 56 days showed that HHP and heat pasteurization had similar results in terms of pH and color (p<0.05). However HHP-treated samples had lower bitterness and protein sensitivity and higher chill haze values than the heat pasteurized samples at the end of the storage period. The microbiological stability of HHP-tr...
Effects of Bentonite Combinations and Gelatin on the Rheological Behaviour of Bentonite – Apple Juice Dispersions
Dik, Tunay; Özilgen, Mustafa (Elsevier BV, 1996-11)
Rheological behaviour of bentonite – apple juice suspensions were experimentally determined at 25°C, within the shear rate range of 4.3 to 43.1 s−1with 0.90, 1.33 and 2.66 g/L bentonite mixtures and 0 to 0.25 g/L (on dry basis) gelatin concentrations. The mixtures consisted of 100%, 80%, 60%, 40% 20% and 0% Ca-bentonite and balance Na-bentonite combinations. The experimental data were described with the power law as τ =Kγ.1.56. The consistency index was related to the calcium, sodium and gelatin concentrati...
Effect of high pressure (HP) on the quality and shelf life of red mullet (Mullus surmelutus)
Erkan, Nuray; Uretener, Gonca; Alpas, Hami (Elsevier BV, 2010-04-01)
The effect of different temperature/time/pressure high hydrostatic pressure (HP) treatment on the quality and shelf life of red mullet were studied Different high pressure treatments (at 3, 7, 15 and 25 degrees C, 5 to 10 min and 220, 250 and 330 MPa) were tested to establish the best processing conditions for the quality of red mullet The effect of the process on the quality of the sample was examined by colour. Trimethylamine nitrogen (TMA-N) and Thiobarbituric acid number (TBA) analysis. Based on the res...
Effects of high hydrostatic pressure on microflora and some quality attributes of grape juice
MERT, Mecnun; BUZRUL, Sencer; Alpas, Hami (2013-03-01)
Red and white grape juices were treated with high hydrostatic pressure (HHP) at three different pressures, temperature and time values to investigate the effects of HHP on natural microflora and some quality attributes of the juices. Increased pressure, temperature and time showed significant effect on the microbial reduction and no microbial growth were observed in HHP-treated grape juices up to 90 days. HHP had little or no effect on pH and color of the juices. Although 5-hydroxymethylfurfural (HMF) forma...
Recovery of strawberry aroma compounds by pervaporation
Isci, A; Şahin, Serpil; Şümnü, Servet Gülüm (Elsevier BV, 2006-07-01)
The main objective of this study was to determine the effects of feed temperature (30, 40, 50 degrees C), concentration (50, 100, 150 ppm), composition (different strawberry model solutions) and permeate pressure (4, 8 mbar) on recovery of strawberry aroma compounds by pervaporation. Pervaporation was performed using a hydrophobic membrane, PERVAP 1070 (PDMS). As the feed temperature increased or downstream pressure decreased, the mass flux and selectivity increased in pervaporation of methyl butyrate (MTB)...
Citation Formats
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.