Colour Changes During Ripening of High Pressure Treated Hard Caprine Cheese

High hydrostatic pressure (HHP) treatment of cheese intended to accelerate ripening. Along with increased proteolysis, some other parameters were affected, colour being one of them. Right after HHP and at the end of ripening time, Hunterlab colour parameters were very similar in both control and cheese treated at 400 MPa, but during ripening they evolved in a different way. HHP-treated cheese had lower lightness and higher chroma values than control cheese and both characteristics were unexpectedly associated to higher moisture values. Those differences are attributed to changes in cheese microstructure.     

Changes in chemical and microbiological characteristics of goat cheese made from raw,pasteurized or high-pressure-treated milk

Abstract

High-pressure treatment offers to the dairy industry a new technique for food preservation. Very little research is available on the use of high pressure and its potential for cheesemaking. The use of high-pressure treated milk to produce goat cheese has been studied. The effect of high pressure on the ripening process of goat cheese, including the microbiological quality of goat milk and cheese has been included.     

High pressure applications in milk treatment for cheese-making and accelerated ripening

Abstract

Several studies have been carried out in order to evaluate the effect of high hydrostatic pressure on food components, its impact on microorganisms and enzymes, and the modifications it produces at the nutritional and sensory level. However, practical applications of high pressure treatment have received little attention. This paper examines our recent ongoing work toward the development of high pressure applications, such as the production of raw milk cheeses from high pressure-treated milk and the possibility of cheese ripening acceleration.     

Analysis of major ovine milk proteins by reversed-phase high-performance liquid chromatography and flow injection analysis with electrospray ionization mass spectrometry

Ovine milk proteins were analyzed both by coupling HPLC and electrospray ionization mass spectrometry (ESI-MS) and by flow injection analysis and ESI-MS detection after separation and collection of fractions from gel permeation chromatography. These methods resolved the four ovine caseins and whey proteins and made it possible to study the complexity of these proteins associated with genetic polymorphism, post-translational changes (phosphorylation and glycosylation) and the presence of multiple forms of proteins. The experimental molecular masses of ewe milk proteins were: 19 373 for κ-casein 3P; 25 616 for _s2-casein 10P; 23 411 for _s1-casein C-8P; 23 750 for β-casein 5P; 18 170 and 18 148 for β-lactoglobulins A and B; 14 152 for -lactalbumin A and 66 322 for serum albumin.     

Evaluation of the importance of germinative cycles for destruction of bacillus cereus spores in miniature cheeses

Our objective was to determine the effect of high pressure on inactivation of spores of Bacillus cereus ATCC 9139 inoculated into cheese made of raw cow's milk. Inoculated miniature cheeses were manufactured under controlled bacteriological conditions, vacuum packed and kept at 8 °C for 15 days after pressure treatment. Cheeses were submitted to pressures of 300, 400 or 500 MPa at 30 °C, during 15 min. Some of them were treated with a germination cycle of 60 MPa at 30 °C for 210 min. Lethality was calculated comparing surviving sample counts to control ones. Adding the germinative cycle resulted in higher efficiency, and when applied with 500 MPa, lethality reached 2.0 log cfu/mL. We saw that with both cycles initial counts of spores diminish, but all of them were not inactivated. However, considering that in raw milk mesophilic spore counts are 2.6-2.9 log cfu/mL, this treatment may be useful.     

Decrease of free amino acids in high-pressure treated cheese

Abstract

High-pressure treatment of cheese has been studied with a view to preserving fresh cheese [1], and also of developing a method of accelerating its ripening [2-7]. While these objectives can be reached, other changes also occur in cheese when high pressure is applied. One of those changes is the decrease of free amino acids (FAA) in cheese treated in pressures over 200-300MPa. In this paper we will try to summarize the results obtained by different research groups, as well as our own. These results have been published separately, but not previously tied together and explained.     

Combination of high pressure with nisin or lysozyme to further process mechanically recovered poultry meat

Abstract

The combined effect of high pressure processing (HPP) and nisin or lysozyme on aerobic mesophile and psychrotrophe populations of mechanically recovered poultry meat (MRPM) was evaluated. Nisin (0, 12.5, 100 and 200ppm) or lysozyme (0 and 150ppm) were added to MRPM, and vacuum-packaged samples were treated at 350 and 450 MPa for 5 and 15min at 20°C. In mesophiles, reductions above 4 log CFU/g were found in some samples. Psychrotrophes proved more sensitive; in MRPM containing 200 ppm of nisin treated at 450 MPa for 15min, no growth was detected (a lethality of more than 8 log units). There was no synergistic effect between HPP and lysozyme. In contrast, combination of HPP and nisin is a promising nonthermal preservation treatment.