Acid coagulation properties and suitability for yogurt production of cows’ milk treated by high-pressure homogenisation

Flavour profiles and survival of starter cultures of yoghurt produced from high-pressure homogenized milk

“…Milk treatment and production of yoghurts UHPH treatment of milk was performed as described previously (Serra et al, 2007), although only one-stage treatments at 200 and 300 MPa were applied. UHPH samples were compared with milk heat-treated in a tubular heat-exchanger (ATI, Granollers, Barcelona, Spain) (90 C for 90 s), homogenized (Rannie, Copenhagen, Denmark) at one stage at 15 MPa and fortified with 3% SMP (HT þ SMP) (54% lactose, 34.04% total protein and 8.02% ash) (Reny Picot, Anleo-Navia, Asturias, Spain).…”

“…After treatment of milk, yoghurts were prepared as described by Serra et al (2007). For the storage study, different samples of yoghurts were prepared for each day of analysis.…”

“…Such ingredients are generally added at levels of 3 or 4%, raising the total solids level to 14-15%, thus increasing the production costs (Amatayakul et al, 2006). Ultra-high pressure homogenization (UHPH) is a promising technology, based on the same principle as conventional homogenization, but working at significantly higher pressures, which is currently being investigated for the manufacture of yoghurt (Serra et al, 2009(Serra et al, , 2008(Serra et al, , 2007. In a previous study (Serra et al, 2007) UHPH samples were compared with heat-treated milk both with and without skim milk powder (SMP) added, and it was concluded that yoghurts made from milk UHPH-treated at 200 or 300 MPa had higher gel firmness, less syneresis and lower titratable acidity than those obtained from conventionally treated milk with SMP.…”

Characterization of volatile compounds in ultra-high-pressure homogenized milk

“…Data of microorganism inactivation in milk have demonstrated the efficiency of UHPH treatments to reduce microbial counts and to obtain a microbial shelf-life similar to that of highpasteurized milk (Brin˜ez, Roig-Sague´s, Herna´ndez-Herrero, & Guamis, 2006;Hayes, Fox, & Kelly, 2005;Pereda, Ferragut, Guamis, & Trujillo, 2006;Pereda, Ferragut, Quevedo, Guamis, & Trujillo, 2007;Thiebaud, Dumay, Picart, Guiraud, & Cheftel, 2003). UHPH has been reported to cause some physico-chemical modifications in milk and milk products such as inactivation of enzymes (Hayes & Kelly, 2003a;Pereda et al, 2007), changes in protein structure (Hayes et al, 2005;Hayes & Kelly, 2003b), reduction of fat globule size (Pereda et al, 2007;Thiebaud et al, 2003), enhanced rennet coagulation properties in cheese manufacture (Zamora, Ferragut, Jaramillo, Guamis, & Trujillo, 2007) and improvement of quality attributes for yogurt production (less syneresis and higher gel firmness) (Serra, Trujillo, Quevedo, Guamis, & Ferragut, 2007). These results suggest that UHPH is a promising technology that could substitute thermal technologies.…”

Opportunities for Ultra-High-Pressure Homogenisation (UHPH) for the Food Industry

“…UHPH treatment of both skim and whole milk improves acid coagulation properties and yoghurt characteristics such as titratable acidity, density, strength and viscoelastic properties of acid gels, aggregation rate and water retention, i.e. lower syneresis, due to the reduction of particle size and the concomitant formation of finer dispersions, as well as whey proteins denaturation and casein micelle dissociation [34,65,66,68]. High levels of proteolysis and lipolysis, and consequently, special volatile profiles, were detected in full-fat yoghurts produced with UHPH-treated milk at 200 MPa; however, UHPH-treatment at 300 MPa resulted in yoghurts with similar biochemical characteristics to those obtained from heat-treated milk supplemented with 3 % skim milk powder, even though no skim milk powder was added to the samples undergoing UHPH treatment [67,69,70].…”