Effects of high pressure and heat treatment on the mineral balance of goats' milk

Abstract

Changes in the distribution of minerals in skim goats' milk by high pressure (400 MPa) and/or heat (85°C for 30 min) treatment have been studied. Heat treatment caused reduced solubility of the calcium, magnesium and phosphorus, and this increased with the severity of heating. In contrast, high pressure released different levels of micellar elements into the soluble phase without causing appreciable changes in pH or ionic calcium concentration. The levels of soluble salts returned to their original values when the heated samples were subjected to high pressure. However, heating pressurized milk resulted in concentrations of soluble minerals that were lower than in control milks, and close to values found in heated milks. The salt balance in goats' milk was less affected by high pressure treatment at 75°C than was that of cows' milk. These results are discussed in relation to the effects of high pressure and heat treatment on mineral equilibrium and micellar structure.

Effect of processing and food matrix on calcium and phosphorous bioavailability from milk-based fruit beverages in Caco-2 cells

“…3), samples followed the same trend seen before for total P content, in which HPP samples did not differ (p N 0.05) from NT samples, but showed higher values (11.5%) (p b 0.05) than TT beverages, which indicates a beneficial effect of high hydrostatic pressure treatment on P bioaccessibility values versus heat treatment under mild conditions. As previously indicated for calcium, De la Fuente et al (1999) noted an increase in soluble P (obtained by ultracentrifugation) of 18% and 14% in cow's and goat's milk after high pressure treatment (400 MPa at 20°C for 10 min), observing no differences in soluble P after mild thermal treatment (85°C for 20 s) versus controls (De la Fuente et al, 1999. However, in our study, P bioaccessibility of TT samples (see Fig.…”

“…However, as far as we are aware, the in vitro bioavailability of phosphorus, as well as comparison of the effect of pasteurization and high-pressure processing on calcium and phosphorus bioavailability in Caco-2 cells have not been investigated to date. To our knowledge, this latter topic has only been reported for calcium and phosphorus in ewe's and cow's milk (pasteurization) (De la Fuente, Olano & Juárez, 1998) and in goat's and cow's milk (pasteurization and highpressure) (De la Fuente, Olano, Casal & Juárez, 1999), but without taking bioavailability into account.…”

High-pressure-induced changes in the rennet coagulation properties of bovine milk

“…The denaturation of b-lactoglobulin (b-lg) or a-lactalbumin (a-la) occurs at 4100 or 4400 MPa, respectively (Lopez-Fandino, Carrascosa, & Olano, 1996;Gaucheron et al, 1997;Huppertz, Fox, & Kelly, 2004a); the majority of denatured b-lg in HP-treated milk is associated with the casein micelles (Huppertz et al, 2004a). Treatment at 4100 MPa increases the level of non-micellar caseins (Lopez-Fandino, De la Fuente, Ramos, & Olano, 1998;Arias, Lopez-Fandino, & Olano, 2000;Huppertz, Fox, & Kelly, 2004e) and minerals (Schrader, Buchheim, & Morr, 1997;LopezFandino et al, 1998;De la Fuente, Olano, Casal, & Juarez, 1999). At pressures 4300 MPa, considerable disruption of casein micelles occurs, as indicated by decreases in micelle size (Desobry-Banon, Richard, & Hardy, 1994;Gaucheron et al, 1997;Needs, Stenning, Gill, Ferragut, & Rich, 2000b;Huppertz et al, 2004a;Huppertz, Fox, & Kelly, 2004b;Huppertz, Grosman, Fox, & Kelly, 2004f).…”

Dissociation of caseins in high pressure-treated bovine milk

“…The reduction in the amount of sedimentable solids on HP treatment of milk is probably the result of HP-induced disruption of casein micelles, resulting in increased levels of soluble caseins (Table 1; Lopez-Fandino et al, 1998;Arias et al, 2000) and minerals (Buchheim et al, 1996;Schrader et al, 1997;Lopez-Fandino et al, 1998;De la Fuente et al, 1999). The level of sedimentable solids was lowest in milk treated at 250 MPa (Table 2); this is consistent with observations of a maximum level of solubilisation of caseins (Table 1; Lopez-Fandino et al, 1998) and minerals (Lopez-Fandino et al, 1998) at 200 MPa.…”

“…Under pressure, hydrophobic and electrostatic interactions between proteins are disrupted (Mozhaev, Heremans, Frank, Masson, & Balny, 1994, 1996 and CCP is solubilised (Buchheim, Schrader, Morr, Frede, & Sch . utt, 1996;Schrader, Buchheim, & Morr, 1997;Lopez-Fandino, De la Fuente, Ramos, Lopez-Fandino & Olano, 1998;De la Fuente, Olano, Casal & Juarez, 1999); as a result, considerable changes in the size, structure and composition of the casein micelles occur.…”