The effects of various pressure treatments (OK, 30K, 60K, 75K psig) and packing medium (water or cocktail sauce) on shucked oysters were investigated. The pH, moisture content, microbiological tests (including aerobic plate count (APC) and anaerobic plate count (ANPC)), enzyme assays (i.e. α-amylase, β-amylase, lipase and peroxidase activities) were conducted...
The variability effect of kinetic data was investigated by simulating orange juice pectinmethylesterase (PME) inactivation with combined processes of high hydrostatic pressure-temperature (100-500 MPa; 20-40°C), applying the Monte Carlo method. Parameters from an Eyring-Arrheniius model that predicts the kinetic inactivation constant (k) as a function of both pressure and temperature...
High hydrostatic pressure (HHP) is the most-widely adopted novel non-thermal technology for the commercial pasteurization of foods. However, HHP-induced inactivation of bacterial spores remains a challenge due their resistance to the treatment limits of currently available industrial HHP units (i.e., ~650 MPa and 50°C). Several reports have demonstrated that high...
The impact of yeast on the aroma and flavor of Vitis vinifera L. cv. 'Pinot Noir' wine was investigated. Due to the presence of naturally occurring yeast and bacteria on grapes and wine equipment, and the influence these microorganisms have on wine, a means of eliminating microorganisms from grape must...
A sensory method was developed to determine cheese texture by hand evaluation. Cheese sensory evaluation was conducted by panelists (n=8) on four commercial samples in duplicates. Standards, descriptors, methods of each attribute evaluation, sample size, and ballot were developed based on panelists' consensus. Fifteen total attributes, divided into five groups,...
This work focused on assessing lipid damage during the storage of frozen Atlantic mackerel (Scomber scombrus) subjected to a high hydrostatic pressure (HHP) treatment (150, 300, 450 MPa with holding times of 0.0, 2.5, and 5.0 min) prior to freezing. The extent of lipid hydrolysis (free fatty acids) and oxidation...
This research focuses on biochemical changes related to quality losses observed in Atlantic mackerel (Scomber scombrus) muscle stored under commercial frozen storage conditions (9 months, -18 ºC) when subjected to high-hydrostatic pressure (HHP) treatments (125, 150, 175 and 200 MPa for 0 min) before freezing. After freezing, free fatty acid...
This study was undertaken to determine the sensory differences in high pressure vs. heat processed food systems after storage at ambient and refrigerated temperatures as determined by a trained sensory panel. Spanish rice and spaghetti with meat sauce were prepared and treated with heat and with high pressure processing (HHP)....
High hydrostatic pressure (HHP) affects the pH of weak acids due to an increased degree of acid dissociation while under pressure. The temporary pH reduction by high pressure in such a case may influence the barotolerance of microorganisms. The objective of this study was to determine the impact of weak...
This research investigated yeast populations and diversity during pre-fermentation cold maceration and alcoholic fermentation of Vitis vinifera L. cv. Pinot noir grapes from a commercial vineyard (Dayton, OR). Fermentations were conducted at the Oregon State University research winery in 100 L tanks while grapes from the same vineyard lot were...