The effect of low pressure-homogenized lactic cultures on the development of proteolysis in cheese slurry

Abstract

The aim of this study was to determine the effect of low pressure-homogenization of lactic acid bacteria (LAB) on the development of proteolysis in the slurry medium. For the slurry, the milk was pasteurized at 65°C for 30 min, cooled to 32°C and coagulated. The curd obtained was blended; the dry matter was adjusted to 30% by adding distilled water, placed into the flasks and autoclaved. The LAB Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, and Lactobacillus helveticus were used in cheese slurry. Homogenization was performed at 30 MPa and 40°C. The cheese slurries were incubated with and without homogenized cultures at 9 and 30°C for up to 72 h. During incubation, the changes in trichloroacetic acid-soluble nitrogen (TCA-SN) and phosphotungstic acid-soluble nitrogen (PTA-SN) as well as pH were monitored. The results showed that pH development was slower in the slurries to which homogenized culture was added. Higher TCA-SN and PTA-SN values were obtained from the slurries incubated at 30°C. Moreover, higher TCA-SN and PTA-SN values were found in the slurries incubated with homogenized mesophilic culture and Lb. helveticus (P<0.05). The results suggested that homogenization of the cultures was a promising method for the acceleration of cheese ripening.

Suitability of high pressure-homogenized milk for the production of probiotic fermented milk containing Lactobacillus paracasei and Lactobacillus acidophilus

“…Improved sensory properties have also been obtained through modulation of some physico-chemical and technological processes (Gardini et al 1999; Patrignani et al 2006, 2007). HPH treatment has potential for several applications such as cell disruption for the recovery of intracellular bio-products and enzymes (Kelly & Muske, 2004), control and enhancement of proteolytic and fermentative activities of some Lactobacillus species (Coskun, 2006; Lanciotti et al 2007), modification of the microstructure and rheology of food emulsions (Guerzoni et al 1997; Floury et al 2000), increasing cheese yield (Lanciotti et al 2004a; Sandra & Dalgleish, 2005; Burns et al 2008). HPH also has great potential for the development of new products, differentiated from traditional products by sensory and structural characteristics or functional properties (Guerzoni et al 1999; Lanciotti et al 2004b; Madadlou et al 2006).…”

Some low homogenization pressures improve certain probiotic characteristics of yogurt culture bacteria and Lactobacillus acidophilus LA-K

“…These findings indicate that increase in homogenization pressure from 0 to 13.80 MPa resulted in increased acid tolerance of the yogurt cultures (LB-12 and ST-M5). Coskun (2006) found that homogenization of lactic acid Shah and Jelen (1990) reported that at pH 1.5, L. delbrueckii ssp. bulgaricus and L. acidophilus proved to be more acid resistant than S. thermophilus strains.…”

“…Homogenization pressures of 6.90 and 10.34 MPa improved the protease activity of S. thermophilus significantly (P < 0.05; Table 3), as determined by the Pr > t values of the differences of the least squares means. Coskun (2006) also stated that addition of attenuated (homogenized) cultures subjected to the homogenization pressure of 30 MPa enhanced the proteolytic activity of the lactic acid bacteria (L. lactis, L. cremoris, L. delbrueckii ssp. bulgaricus, and S. thermophilus).…”

“…Recently, Donsì et al (2009) reported that inactivation of Escherichia coli increased from 1 to 5 log cycles upon increasing the homogenization pressure from 100 to 300 MPa. Coskun (2006) reported that mesophilic lactic acid bacteria (Lactococcus lactis ssp. lactis and Lactococcus lactis ssp.…”

Proteolysis of Cheese Slurry Made from Pulsed Electric Field-Treated Milk

“…Cheese slurry system that allows cheese to ripen at 30°C for 5 to 30 days has been used as a quick tool to evaluate the contribution of different components into the cheese (Kristoffersen et al 1967;Farkye et al 1995;Muehlenkamp-Ulate and Warthesen 1999;Coskun 2006;Kumar et al 2007).…”