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...
The aroma of milk has been often defined as bland and pleasant, yet characteristic. Conventional thermal processing of milk can certainly extend shelf life, but inevitably changes its flavor. High pressure processing has been suggested as an alternative for milk pasteurization with improved fresh flavor retention. The objective of this...
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...
High hydrostatic pressure processing (HPP) is a nonthermal process in which foods are subjected to pressures in the range of 100-700 MPa at room temperatures or higher. HPP is effective in reducing microbial counts and enzyme activity. The ability of HPP to modify the functional properties of proteins has become...
Microbial lethality is strongly pH dependent in processing regimes including
high hydrostatic pressure processing (HPP). HPP induces the dissociation of
weak acids that potentially causes a shift in pH in some systems thereby increasing
acidity while pressure insensitive buffers do not undergo dissociation. The
degree of high pressure induced pH...
Different strains of Vibrio parahaemolyticus (Vp) in broth cultures and Vp-inoculated live Pacific oysters (Crassostrea gigas) were subjected to high pressure processing (HPP) at 241, 276, 310, and 345 MPa. Results showed Vp numbers were reduced by HPP in both pure culture and whole oysters. Vp inactivation was dependent on...
Whole oysters were processed under a series of pressures from 30,000 to 45,000 psi at different holding times (0, 1, and 2 min) and then stored at <4°C, for 27 d. During the shelf-life study, the quality of oysters was determined by measuring pH, moisture content, and microbial counts including...
Nanostructured ceramics offer significant improvements in properties over the
corresponding materials with grain sizes on the order of tens to hundreds of microns.
Silicon carbide (SiC) is an important structural ceramic whose properties can
potentially be enhanced due to nanoscale microstructures. It has been suggested that
SiC samples with grain...
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,...
High pressure processing was investigated for controlling Cheddar cheese ripening. One-month- or 4-month-old Cheddar cheeses were subjected to pressures ranging from 200 to 800 MPa for 5 min at 25 °C. The number of viable Lactococcus lactis (starter) and Lactobacillus (nonstarter) cells decreased as pressure increased. Subsequent storage of the...
