Microbiological and Chemical Changes in High-Pressure-Treated Milk during Refrigerated Storage

1998 ◽  
Vol 61 (6) ◽  
pp. 735-737 ◽  
Author(s):  
M. R. GARCÍA-RISCO ◽  
E. CORTÉS ◽  
A. V. CARRASCOSA ◽  
R. LÓPEZ-FANDIÑO
Keyword(s):  
High Pressure ◽  
Capillary Electrophoresis ◽  
Shelf Life ◽  
Biochemical Changes ◽  
Point Of View ◽  
Pressure Treatment ◽  
Refrigerated Storage ◽  
Chemical Changes ◽  
Casein Hydrolysis ◽  
High Pressure Treatment

The microbiological and biochemical changes during storage of high-pressure-treated (400 MPa at 25°C, for 30 min) whole (3.5% fat) and skim (0.3% fat) milk at refrigeration temperatures (7°C) were studied. From a microbiological point of view, high-pressure treatment of milk led to an increase in the shelf life because, after 45 days of refrigerated storage, the psychrotrophic and pseudomonad counts of the pressurized milk were lower than those of the unpressurized milk after 15 days. Capillary electrophoresis of the casein fraction showed that proteolysis by bacterial proteinases was not relevant in high-pressure-treated milk, as evidenced by a negligible degradation of κ-casein. However, since the pressure conditions assayed did not lead to plasmin inactivation, considerable (β-, αS2- and αS1-casein hydrolysis took place during refrigerated storage, which can be responsible for flavor defects. No significant differences were found between skim and whole high-pressure-treated milks.

scholarly journals Extension of the Shelf Life of Prawns (Penaeus japonicus) by Vacuum Packaging and High-Pressure Treatment

2000 ◽  
Vol 63 (10) ◽  
pp. 1381-1388 ◽  
Author(s):  
M. E. LÓPEZ-CABALLERO ◽  
M. PÉREZ-MATEOS ◽  
J. A. BORDERÍAS ◽  
P. MONTERO
Keyword(s):  
High Pressure ◽  
Shelf Life ◽  
High Pressures ◽  
Vacuum Packaging ◽  
Point Of View ◽  
Pressure Treatment ◽  
High Pressure Treatment ◽  
Penaeus Japonicus ◽  
Muscle Color ◽  
Number Of Bacteria

The present study has investigated the application of high pressures (200 and 400 MPa) in chilled prawn tails, both conventionally stored (air) and vacuum packaged. Vacuum packaging and high-pressure treatment did extend the shelf life of the prawn samples, although it did affect muscle color very slightly, giving it a whiter appearance. The viable shelf life of 1 week for the air-stored samples was extended to 21 days in the vacuum-packed samples, 28 days in the samples treated at 200 MPa, and 35 days in the samples pressurized at 400 MPa. Vacuum packaging checked the onset of blackening, whereas high-pressure treatment aggravated the problem. From a microbiological point of view, batches conventionally stored reached about 6 log CFU/g or even higher at 14 days. Similar figures were reached in total number of bacteria in vacuum-packed samples and in pressurized at 200-MPa samples at 21 days. When samples were pressurized at 400 MPa, total numbers of bacteria were below 5.5 log CFU/g at 35 days of storage. Consequently, a combination of vacuum packaging and high-pressure treatment would appear to be beneficial in prolonging freshness and preventing spotting.

scholarly journals Proteins and proteolytic activity changes during refrigerated storage in sea bass (Dicentrarchus labrax L.) muscle after high-pressure treatment

2005 ◽  
Vol 222 (5-6) ◽  
pp. 527-535 ◽  
Author(s):  
Romuald Chéret ◽  
Aránzazu Hernández-Andrés ◽  
Christine Delbarre-Ladrat ◽  
Marie de Lamballerie ◽  
Véronique Verrez-Bagnis
Keyword(s):  
High Pressure ◽  
Proteolytic Activity ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Pressure Treatment ◽  
Refrigerated Storage ◽  
High Pressure Treatment

scholarly journals Chemical Changes in Chilled Farmed Salmon (Oncorhynchus kisutch): Effect of Previous High Pressure Treatment

2009 ◽  
Vol 27 (Special Issue 1) ◽  
pp. S20-S22
Author(s):  
A. Rodríguez ◽  
I. Ortea ◽  
M. Trigo ◽  
Y. Sierra ◽  
J. M Gallardo ◽  
...  
Keyword(s):  
High Pressure ◽  
Marked Effect ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Pressure Treatment ◽  
Protein Breakdown ◽  
Chemical Changes ◽  
High Pressure Treatment ◽  
Farmed Salmon ◽  
Nucleotide Degradation

Coho salmon <I>(Oncorhynchus kisutch</I>) has recently attracted a great interest as a farmed product. This research focuses on its commercialisation as a chilled product. Thus, the effect of a previous hydrostatic high pressure (HHP) treatment on chemical changes related to quality loss was studied. A marked effect of HHP treatment was observed on lipid hydrolysis (free fatty acid formation), lipid oxidation (primary, secondary and tertiary compounds) and protein breakdown (sarcoplasmic fraction) throughout the chilling storage; however, no influence could be observed on nucleotide degradation and polyene index. Sensory analysis (putrid and amine odour development) showed a profitable effect of HHP on chilled salmon quality; however, no effect could be concluded on rancid odour development.

High-Pressure Treatment for Shelf-Life Extension and Quality Improvement of Oysters Cooked in a Traditional Taiwanese Oyster Omelet

2010 ◽  
Vol 73 (1) ◽  
pp. 53-61 ◽  
Author(s):  
KUNG-MING LAI ◽  
HSIN-YI CHI ◽  
KUO-CHIANG HSU
Keyword(s):  
High Pressure ◽  
Lipid Oxidation ◽  
Shelf Life ◽  
Bacterial Load ◽  
Life Extension ◽  
Pressure Treatment ◽  
High Pressure Treatment ◽  
Microbial Counts ◽  
Unpleasant Odor ◽  
Oxidation Growth

Whole oysters were processed using high-pressure (HP) treatment at 250 and 300 MPa for 0 to 10 min and stored at 4°C for up to 28 days. HP-treated oysters and untreated oysters were evaluated for lipid oxidation, growth of microorganisms, and sensory characteristics after cooking at 160°C for 90 s. Microbial counts after HP treatment revealed that the bacterial load was initially reduced at all pressures. HP-treated oysters had significantly higher pH and moisture (P &lt; 0.05) relative to control (untreated) oysters during storage. HP treatment increased lipid oxidation with unpleasant odor during storage compared with the control. HP treatment decreased redness but did not significantly affect the brightness and yellowness of cooked oysters. From tests of mechanical properties, 300 MPa-treated oysters after cooking had significantly increased toughness as measured by cutting force. HP-treated oysters after cooking received higher quality scores than did the control during the storage trial. Results indicated that 300 MPa for 2 min is the optimum HP treatment that results in oysters most acceptable for oyster omelets during storage at 4°C, and this treatment may extend the shelf life of these oysters to 21 days.

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