The overall aim of this thesis is to determine if the interactions between normal and waxy rice starch and milk proteins from four milk protein ingredients, namely skim milk powder (SMP), milk protein concentrate (MPC), sodium caseinate (NaCAS) and whey protein isolate (WPI) do occur, and to identify the mechanisms underlying these interactions. Different milk protein ingredients at various concentrations (0 to 10%, w/w) affected markedly and differently the pasting behaviour of 10% (w/w) rice starches. SMP delayed the pasting of both rice starches by increasing the onset temperature (Tonset) and the peak viscosity temperature (Tpeak) of pasting. This was mainly due to the presence of lactose and ions, which was further supported by the investigation of the effects of UFSMP (a solution of salts and lactose present in SMP at their proper concentration) and lactose. The addition of NaCAS also delayed the pasting of rice starch; Tpeak in the case of both starches was increased. For normal rice starch paste, MPC and WPI decreased the Tpeak. MPC had no affect on Tpeak of waxy rice starch paste. The qualitative viscoelastic behaviour of rice starch/milk protein ingredient gels obtained from the above pastes was dominated by the continuous phase made of the starch molecules. There was evidence, as indicated by confocal microscopy, of phase separation between the milk proteins of SMP and MPC and the two starches. The phase separation was not observed in the addition of either NaCAS or WPI. Studies on the thermal behaviour of rice starch/milk protein ingredient mixtures by differential scanning calorimetry (DSC) showed that SMP, similarly to UFSMP, delayed the gelatinization of both starches. NaCAS also delayed the gelatinisation of both starches but had a greater effect on waxy than normal rice starch. The addition of NaCAS did not affect Tonset but increased Tpeak for normal rice starch, whereas the gelatinisation temperature of waxy rice starch was highly affected by the addition of NaCAS with both Tonset and Tpeak shifted to higher temperatures. MPC had no affect on the gelatinization temperature of normal rice starch, whereas the gelatinization temperature of waxy rice starch was increased by the addition of MPC. The addition of WPI to both rice starches showed two thermal transitions. The first of these was due to the gelatinisation of the starches and the second to the denaturation of ß-lactoglobulin (ß-lg). The addition of WPI to normal rice starch showed that the thermal behaviour of normal starch and protein were independent from each other. In contrast, the thermal behaviour of waxy rice starch was modified by the addition of WPI; both Tonset and Tpeak were increased. SMP decreased the Tonset of swelling, swelling ratio and the amount of starch leaching from both starches. These observed changes were due to the presence of lactose and ions in SMP. NaCAS slightly increased Tonset of swelling but the amount of starch leaching was reduced for both rice starches. The rigidity of both starches tended to increase in the presence of NaCAS. MPC and WPI affected the swelling behaviour of normal and waxy rice starch differently. A dramatic increase in the swelling of normal rice starch/MPC or WPI mixtures was observed, whereas this trend was not evident for waxy rice starch/ MPC or WPI mixtures. The difference in the water holding ability and gelatinization peak temperatures of the two starches over the temperature range at which whey proteins denature and form gels are believed to be responsible for the observed differences. The results from confocal microscopy showed that milk proteins, such as a-casein, ß- casein, ß-lg and a-lactalbumin (a-la), were adsorbed onto the granule surface of both normal and waxy rice starch. The mechanism for this adsorption is the hydrophilic interactions; hydrogen bonds between hydroxyl group from terminated glucan molecule that protrude around starch granule surface-hydroxyl; amino, or other electron-donation or electron-accepting groups of the added proteins. Using sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) it was found that for SMP and MPC the adsorbed as- to ß-casein ratio on both starches was similar to the as-casein to ß- casein ratio in the casein micelle at low SMP and MPC concentrations. But at high concentrations of SMP or MPC, this ratio decreased indicating that more ß-casein was adsorbed preferentially to as-casein. In the case of NaCAS, as-casein was adsorbed preferentially to ß-casein. Moreover, there was evidence of multilayer adsorption of ascasein into the surface of rice starch granules. Compared to the other milk protein ingredients, very small amounts of the ß-lg and a-la from WPI were adsorbed onto starch granules. However, the adsorbed amounts of ß-lg and a-la from WPI continuously increased with increasing WPI concentration, suggesting that these two proteins, particularly ß-lg, adsorbed in multilayers too.

The overall aim of this thesis is to determine if the interactions between normal and waxy rice starch and milk proteins from four milk protein ingredients, namely skim milk powder (SMP), milk protein concentrate (MPC), sodium caseinate (NaCAS) and whey protein isolate (WPI) do occur, and to identify the mechanisms underlying these interactions. Different milk protein ingredients at various concentrations (0 to 10%, w/w) affected markedly and differently the pasting behaviour of 10% (w/w) rice starches. SMP delayed the pasting of both rice starches by increasing the onset temperature (Tonset) and the peak viscosity temperature (Tpeak) of pasting. This was mainly due to the presence of lactose and ions, which was further supported by the investigation of the effects of UFSMP (a solution of salts and lactose present in SMP at their proper concentration) and lactose. The addition of NaCAS also delayed the pasting of rice starch; Tpeak in the case of both starches was increased. For normal rice starch paste, MPC and WPI decreased the Tpeak. MPC had no affect on Tpeak of waxy rice starch paste. The qualitative viscoelastic behaviour of rice starch/milk protein ingredient gels obtained from the above pastes was dominated by the continuous phase made of the starch molecules. There was evidence, as indicated by confocal microscopy, of phase separation between the milk proteins of SMP and MPC and the two starches. The phase separation was not observed in the addition of either NaCAS or WPI. Studies on the thermal behaviour of rice starch/milk protein ingredient mixtures by differential scanning calorimetry (DSC) showed that SMP, similarly to UFSMP, delayed the gelatinization of both starches. NaCAS also delayed the gelatinisation of both starches but had a greater effect on waxy than normal rice starch. The addition of NaCAS did not affect Tonset but increased Tpeak for normal rice starch, whereas the gelatinisation temperature of waxy rice starch was highly affected by the addition of NaCAS with both Tonset and Tpeak shifted to higher temperatures. MPC had no affect on the gelatinization temperature of normal rice starch, whereas the gelatinization temperature of waxy rice starch was increased by the addition of MPC. The addition of WPI to both rice starches showed two thermal transitions. The first of these was due to the gelatinisation of the starches and the second to the denaturation of ß-lactoglobulin (ß-lg). The addition of WPI to normal rice starch showed that the thermal behaviour of normal starch and protein were independent from each other. In contrast, the thermal behaviour of waxy rice starch was modified by the addition of WPI; both Tonset and Tpeak were increased. SMP decreased the Tonset of swelling, swelling ratio and the amount of starch leaching from both starches. These observed changes were due to the presence of lactose and ions in SMP. NaCAS slightly increased Tonset of swelling but the amount of starch leaching was reduced for both rice starches. The rigidity of both starches tended to increase in the presence of NaCAS. MPC and WPI affected the swelling behaviour of normal and waxy rice starch differently. A dramatic increase in the swelling of normal rice starch/MPC or WPI mixtures was observed, whereas this trend was not evident for waxy rice starch/ MPC or WPI mixtures. The difference in the water holding ability and gelatinization peak temperatures of the two starches over the temperature range at which whey proteins denature and form gels are believed to be responsible for the observed differences. The results from confocal microscopy showed that milk proteins, such as a-casein, ß- casein, ß-lg and a-lactalbumin (a-la), were adsorbed onto the granule surface of both normal and waxy rice starch. The mechanism for this adsorption is the hydrophilic interactions; hydrogen bonds between hydroxyl group from terminated glucan molecule that protrude around starch granule surface-hydroxyl; amino, or other electron-donation or electron-accepting groups of the added proteins. Using sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) it was found that for SMP and MPC the adsorbed as- to ß-casein ratio on both starches was similar to the as-casein to ß- casein ratio in the casein micelle at low SMP and MPC concentrations. But at high concentrations of SMP or MPC, this ratio decreased indicating that more ß-casein was adsorbed preferentially to as-casein. In the case of NaCAS, as-casein was adsorbed preferentially to ß-casein. Moreover, there was evidence of multilayer adsorption of ascasein into the surface of rice starch granules. Compared to the other milk protein ingredients, very small amounts of the ß-lg and a-la from WPI were adsorbed onto starch granules. However, the adsorbed amounts of ß-lg and a-la from WPI continuously increased with increasing WPI concentration, suggesting that these two proteins, particularly ß-lg, adsorbed in multilayers too.

The overall aim of this thesis is to determine if the interactions between normal and waxy rice starch and milk proteins from four milk protein ingredients, namely skim milk powder (SMP), milk protein concentrate (MPC), sodium caseinate (NaCAS) and whey protein isolate (WPI) do occur, and to identify the mechanisms underlying these interactions. Different milk protein ingredients at various concentrations (0 to 10%, w/w) affected markedly and differently the pasting behaviour of 10% (w/w) rice starches. SMP delayed the pasting of both rice starches by increasing the onset temperature (Tonset) and the peak viscosity temperature (Tpeak) of pasting. This was mainly due to the presence of lactose and ions, which was further supported by the investigation of the effects of UFSMP (a solution of salts and lactose present in SMP at their proper concentration) and lactose. The addition of NaCAS also delayed the pasting of rice starch; Tpeak in the case of both starches was increased. For normal rice starch paste, MPC and WPI decreased the Tpeak. MPC had no affect on Tpeak of waxy rice starch paste. The qualitative viscoelastic behaviour of rice starch/milk protein ingredient gels obtained from the above pastes was dominated by the continuous phase made of the starch molecules. There was evidence, as indicated by confocal microscopy, of phase separation between the milk proteins of SMP and MPC and the two starches. The phase separation was not observed in the addition of either NaCAS or WPI. Studies on the thermal behaviour of rice starch/milk protein ingredient mixtures by differential scanning calorimetry (DSC) showed that SMP, similarly to UFSMP, delayed the gelatinization of both starches. NaCAS also delayed the gelatinisation of both starches but had a greater effect on waxy than normal rice starch. The addition of NaCAS did not affect Tonset but increased Tpeak for normal rice starch, whereas the gelatinisation temperature of waxy rice starch was highly affected by the addition of NaCAS with both Tonset and Tpeak shifted to higher temperatures. MPC had no affect on the gelatinization temperature of normal rice starch, whereas the gelatinization temperature of waxy rice starch was increased by the addition of MPC. The addition of WPI to both rice starches showed two thermal transitions. The first of these was due to the gelatinisation of the starches and the second to the denaturation of ß-lactoglobulin (ß-lg). The addition of WPI to normal rice starch showed that the thermal behaviour of normal starch and protein were independent from each other. In contrast, the thermal behaviour of waxy rice starch was modified by the addition of WPI; both Tonset and Tpeak were increased. SMP decreased the Tonset of swelling, swelling ratio and the amount of starch leaching from both starches. These observed changes were due to the presence of lactose and ions in SMP. NaCAS slightly increased Tonset of swelling but the amount of starch leaching was reduced for both rice starches. The rigidity of both starches tended to increase in the presence of NaCAS. MPC and WPI affected the swelling behaviour of normal and waxy rice starch differently. A dramatic increase in the swelling of normal rice starch/MPC or WPI mixtures was observed, whereas this trend was not evident for waxy rice starch/ MPC or WPI mixtures. The difference in the water holding ability and gelatinization peak temperatures of the two starches over the temperature range at which whey proteins denature and form gels are believed to be responsible for the observed differences. The results from confocal microscopy showed that milk proteins, such as a-casein, ß- casein, ß-lg and a-lactalbumin (a-la), were adsorbed onto the granule surface of both normal and waxy rice starch. The mechanism for this adsorption is the hydrophilic interactions; hydrogen bonds between hydroxyl group from terminated glucan molecule that protrude around starch granule surface-hydroxyl; amino, or other electron-donation or electron-accepting groups of the added proteins. Using sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) it was found that for SMP and MPC the adsorbed as- to ß-casein ratio on both starches was similar to the as-casein to ß- casein ratio in the casein micelle at low SMP and MPC concentrations. But at high concentrations of SMP or MPC, this ratio decreased indicating that more ß-casein was adsorbed preferentially to as-casein. In the case of NaCAS, as-casein was adsorbed preferentially to ß-casein. Moreover, there was evidence of multilayer adsorption of ascasein into the surface of rice starch granules. Compared to the other milk protein ingredients, very small amounts of the ß-lg and a-la from WPI were adsorbed onto starch granules. However, the adsorbed amounts of ß-lg and a-la from WPI continuously increased with increasing WPI concentration, suggesting that these two proteins, particularly ß-lg, adsorbed in multilayers too.

The overall aim of this thesis is to determine if the interactions between normal and waxy rice starch and milk proteins from four milk protein ingredients, namely skim milk powder (SMP), milk protein concentrate (MPC), sodium caseinate (NaCAS) and whey protein isolate (WPI) do occur, and to identify the mechanisms underlying these interactions. Different milk protein ingredients at various concentrations (0 to 10%, w/w) affected markedly and differently the pasting behaviour of 10% (w/w) rice starches. SMP delayed the pasting of both rice starches by increasing the onset temperature (Tonset) and the peak viscosity temperature (Tpeak) of pasting. This was mainly due to the presence of lactose and ions, which was further supported by the investigation of the effects of UFSMP (a solution of salts and lactose present in SMP at their proper concentration) and lactose. The addition of NaCAS also delayed the pasting of rice starch; Tpeak in the case of both starches was increased. For normal rice starch paste, MPC and WPI decreased the Tpeak. MPC had no affect on Tpeak of waxy rice starch paste. The qualitative viscoelastic behaviour of rice starch/milk protein ingredient gels obtained from the above pastes was dominated by the continuous phase made of the starch molecules. There was evidence, as indicated by confocal microscopy, of phase separation between the milk proteins of SMP and MPC and the two starches. The phase separation was not observed in the addition of either NaCAS or WPI. Studies on the thermal behaviour of rice starch/milk protein ingredient mixtures by differential scanning calorimetry (DSC) showed that SMP, similarly to UFSMP, delayed the gelatinization of both starches. NaCAS also delayed the gelatinisation of both starches but had a greater effect on waxy than normal rice starch. The addition of NaCAS did not affect Tonset but increased Tpeak for normal rice starch, whereas the gelatinisation temperature of waxy rice starch was highly affected by the addition of NaCAS with both Tonset and Tpeak shifted to higher temperatures. MPC had no affect on the gelatinization temperature of normal rice starch, whereas the gelatinization temperature of waxy rice starch was increased by the addition of MPC. The addition of WPI to both rice starches showed two thermal transitions. The first of these was due to the gelatinisation of the starches and the second to the denaturation of ß-lactoglobulin (ß-lg). The addition of WPI to normal rice starch showed that the thermal behaviour of normal starch and protein were independent from each other. In contrast, the thermal behaviour of waxy rice starch was modified by the addition of WPI; both Tonset and Tpeak were increased. SMP decreased the Tonset of swelling, swelling ratio and the amount of starch leaching from both starches. These observed changes were due to the presence of lactose and ions in SMP. NaCAS slightly increased Tonset of swelling but the amount of starch leaching was reduced for both rice starches. The rigidity of both starches tended to increase in the presence of NaCAS. MPC and WPI affected the swelling behaviour of normal and waxy rice starch differently. A dramatic increase in the swelling of normal rice starch/MPC or WPI mixtures was observed, whereas this trend was not evident for waxy rice starch/ MPC or WPI mixtures. The difference in the water holding ability and gelatinization peak temperatures of the two starches over the temperature range at which whey proteins denature and form gels are believed to be responsible for the observed differences. The results from confocal microscopy showed that milk proteins, such as a-casein, ß- casein, ß-lg and a-lactalbumin (a-la), were adsorbed onto the granule surface of both normal and waxy rice starch. The mechanism for this adsorption is the hydrophilic interactions; hydrogen bonds between hydroxyl group from terminated glucan molecule that protrude around starch granule surface-hydroxyl; amino, or other electron-donation or electron-accepting groups of the added proteins. Using sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) it was found that for SMP and MPC the adsorbed as- to ß-casein ratio on both starches was similar to the as-casein to ß- casein ratio in the casein micelle at low SMP and MPC concentrations. But at high concentrations of SMP or MPC, this ratio decreased indicating that more ß-casein was adsorbed preferentially to as-casein. In the case of NaCAS, as-casein was adsorbed preferentially to ß-casein. Moreover, there was evidence of multilayer adsorption of ascasein into the surface of rice starch granules. Compared to the other milk protein ingredients, very small amounts of the ß-lg and a-la from WPI were adsorbed onto starch granules. However, the adsorbed amounts of ß-lg and a-la from WPI continuously increased with increasing WPI concentration, suggesting that these two proteins, particularly ß-lg, adsorbed in multilayers too.

The overall aim of this thesis is to determine if the interactions between normal and waxy rice starch and milk proteins from four milk protein ingredients, namely skim milk powder (SMP), milk protein concentrate (MPC), sodium caseinate (NaCAS) and whey protein isolate (WPI) do occur, and to identify the mechanisms underlying these interactions. Different milk protein ingredients at various concentrations (0 to 10%, w/w) affected markedly and differently the pasting behaviour of 10% (w/w) rice starches. SMP delayed the pasting of both rice starches by increasing the onset temperature (Tonset) and the peak viscosity temperature (Tpeak) of pasting. This was mainly due to the presence of lactose and ions, which was further supported by the investigation of the effects of UFSMP (a solution of salts and lactose present in SMP at their proper concentration) and lactose. The addition of NaCAS also delayed the pasting of rice starch; Tpeak in the case of both starches was increased. For normal rice starch paste, MPC and WPI decreased the Tpeak. MPC had no affect on Tpeak of waxy rice starch paste. The qualitative viscoelastic behaviour of rice starch/milk protein ingredient gels obtained from the above pastes was dominated by the continuous phase made of the starch molecules. There was evidence, as indicated by confocal microscopy, of phase separation between the milk proteins of SMP and MPC and the two starches. The phase separation was not observed in the addition of either NaCAS or WPI. Studies on the thermal behaviour of rice starch/milk protein ingredient mixtures by differential scanning calorimetry (DSC) showed that SMP, similarly to UFSMP, delayed the gelatinization of both starches. NaCAS also delayed the gelatinisation of both starches but had a greater effect on waxy than normal rice starch. The addition of NaCAS did not affect Tonset but increased Tpeak for normal rice starch, whereas the gelatinisation temperature of waxy rice starch was highly affected by the addition of NaCAS with both Tonset and Tpeak shifted to higher temperatures. MPC had no affect on the gelatinization temperature of normal rice starch, whereas the gelatinization temperature of waxy rice starch was increased by the addition of MPC. The addition of WPI to both rice starches showed two thermal transitions. The first of these was due to the gelatinisation of the starches and the second to the denaturation of ß-lactoglobulin (ß-lg). The addition of WPI to normal rice starch showed that the thermal behaviour of normal starch and protein were independent from each other. In contrast, the thermal behaviour of waxy rice starch was modified by the addition of WPI; both Tonset and Tpeak were increased. SMP decreased the Tonset of swelling, swelling ratio and the amount of starch leaching from both starches. These observed changes were due to the presence of lactose and ions in SMP. NaCAS slightly increased Tonset of swelling but the amount of starch leaching was reduced for both rice starches. The rigidity of both starches tended to increase in the presence of NaCAS. MPC and WPI affected the swelling behaviour of normal and waxy rice starch differently. A dramatic increase in the swelling of normal rice starch/MPC or WPI mixtures was observed, whereas this trend was not evident for waxy rice starch/ MPC or WPI mixtures. The difference in the water holding ability and gelatinization peak temperatures of the two starches over the temperature range at which whey proteins denature and form gels are believed to be responsible for the observed differences. The results from confocal microscopy showed that milk proteins, such as a-casein, ß- casein, ß-lg and a-lactalbumin (a-la), were adsorbed onto the granule surface of both normal and waxy rice starch. The mechanism for this adsorption is the hydrophilic interactions; hydrogen bonds between hydroxyl group from terminated glucan molecule that protrude around starch granule surface-hydroxyl; amino, or other electron-donation or electron-accepting groups of the added proteins. Using sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) it was found that for SMP and MPC the adsorbed as- to ß-casein ratio on both starches was similar to the as-casein to ß- casein ratio in the casein micelle at low SMP and MPC concentrations. But at high concentrations of SMP or MPC, this ratio decreased indicating that more ß-casein was adsorbed preferentially to as-casein. In the case of NaCAS, as-casein was adsorbed preferentially to ß-casein. Moreover, there was evidence of multilayer adsorption of ascasein into the surface of rice starch granules. Compared to the other milk protein ingredients, very small amounts of the ß-lg and a-la from WPI were adsorbed onto starch granules. However, the adsorbed amounts of ß-lg and a-la from WPI continuously increased with increasing WPI concentration, suggesting that these two proteins, particularly ß-lg, adsorbed in multilayers too.

The overall aim of this thesis is to determine if the interactions between normal and waxy rice starch and milk proteins from four milk protein ingredients, namely skim milk powder (SMP), milk protein concentrate (MPC), sodium caseinate (NaCAS) and whey protein isolate (WPI) do occur, and to identify the mechanisms underlying these interactions. Different milk protein ingredients at various concentrations (0 to 10%, w/w) affected markedly and differently the pasting behaviour of 10% (w/w) rice starches. SMP delayed the pasting of both rice starches by increasing the onset temperature (Tonset) and the peak viscosity temperature (Tpeak) of pasting. This was mainly due to the presence of lactose and ions, which was further supported by the investigation of the effects of UFSMP (a solution of salts and lactose present in SMP at their proper concentration) and lactose. The addition of NaCAS also delayed the pasting of rice starch; Tpeak in the case of both starches was increased. For normal rice starch paste, MPC and WPI decreased the Tpeak. MPC had no affect on Tpeak of waxy rice starch paste. The qualitative viscoelastic behaviour of rice starch/milk protein ingredient gels obtained from the above pastes was dominated by the continuous phase made of the starch molecules. There was evidence, as indicated by confocal microscopy, of phase separation between the milk proteins of SMP and MPC and the two starches. The phase separation was not observed in the addition of either NaCAS or WPI. Studies on the thermal behaviour of rice starch/milk protein ingredient mixtures by differential scanning calorimetry (DSC) showed that SMP, similarly to UFSMP, delayed the gelatinization of both starches. NaCAS also delayed the gelatinisation of both starches but had a greater effect on waxy than normal rice starch. The addition of NaCAS did not affect Tonset but increased Tpeak for normal rice starch, whereas the gelatinisation temperature of waxy rice starch was highly affected by the addition of NaCAS with both Tonset and Tpeak shifted to higher temperatures. MPC had no affect on the gelatinization temperature of normal rice starch, whereas the gelatinization temperature of waxy rice starch was increased by the addition of MPC. The addition of WPI to both rice starches showed two thermal transitions. The first of these was due to the gelatinisation of the starches and the second to the denaturation of ß-lactoglobulin (ß-lg). The addition of WPI to normal rice starch showed that the thermal behaviour of normal starch and protein were independent from each other. In contrast, the thermal behaviour of waxy rice starch was modified by the addition of WPI; both Tonset and Tpeak were increased. SMP decreased the Tonset of swelling, swelling ratio and the amount of starch leaching from both starches. These observed changes were due to the presence of lactose and ions in SMP. NaCAS slightly increased Tonset of swelling but the amount of starch leaching was reduced for both rice starches. The rigidity of both starches tended to increase in the presence of NaCAS. MPC and WPI affected the swelling behaviour of normal and waxy rice starch differently. A dramatic increase in the swelling of normal rice starch/MPC or WPI mixtures was observed, whereas this trend was not evident for waxy rice starch/ MPC or WPI mixtures. The difference in the water holding ability and gelatinization peak temperatures of the two starches over the temperature range at which whey proteins denature and form gels are believed to be responsible for the observed differences. The results from confocal microscopy showed that milk proteins, such as a-casein, ß- casein, ß-lg and a-lactalbumin (a-la), were adsorbed onto the granule surface of both normal and waxy rice starch. The mechanism for this adsorption is the hydrophilic interactions; hydrogen bonds between hydroxyl group from terminated glucan molecule that protrude around starch granule surface-hydroxyl; amino, or other electron-donation or electron-accepting groups of the added proteins. Using sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE) it was found that for SMP and MPC the adsorbed as- to ß-casein ratio on both starches was similar to the as-casein to ß- casein ratio in the casein micelle at low SMP and MPC concentrations. But at high concentrations of SMP or MPC, this ratio decreased indicating that more ß-casein was adsorbed preferentially to as-casein. In the case of NaCAS, as-casein was adsorbed preferentially to ß-casein. Moreover, there was evidence of multilayer adsorption of ascasein into the surface of rice starch granules. Compared to the other milk protein ingredients, very small amounts of the ß-lg and a-la from WPI were adsorbed onto starch granules. However, the adsorbed amounts of ß-lg and a-la from WPI continuously increased with increasing WPI concentration, suggesting that these two proteins, particularly ß-lg, adsorbed in multilayers too.

The aim of study was to evaluate milk efficiency of sheep Original Valachian (OV). Observation took place in the period 2006-2009 and were involved 123 ovine. Samples were taken from the morning milking during the months April to August (method ET). Milking proces was realised mechanically. In 84 sheep were known genotypes AA (n = 13), AB (n = 18), BB (n = 53). After evaluation of essential components of ewe{\crq}s milk from flock of lambing ewes OV during lactation were found these average values: Fat (F) 4,90 g.100g-1, crude protein (CP) 5,94 g.100g-1, casein (CAS) 4,40 g.100g-1, serum protein (SP) 1,18 g.100g-1, lactose (L) 5,07 g.100g-1, dry matter (DM) 16,45 g.100g-1, solid not fat (SNF) 11,63 g.100g-1 and utilizable dry matter (UDM) 10,85 g.100g-1. Average daily milk yield of OV was 0,70 l. Effect of stage of lactation was provable on all the indicators in the level of significance 0,001. It was evidenced a statistically significant effect of the control year on the content of SNF (P{<}0,05), on the L (P{<}0,01) and on all other components (P{<}0,001). At comparing milk production OV according to the genetic polymorphism of {$\beta$}-lactoglobulin have been identified probably significant differences in milk yield (P{<}0,05). The highest daily milk yield reached genotype AB (0,76 l.day-1) {>} BB (0,68 l.day-1) {>} AA (0,66 l.day-1). In AB genotype was found the lowest levels of these essential components F, CP, CAS, DM, SNF and UDM. Highly significant effect of genotype was found on content of L (P{<}0,001). The highest content of L was confirmed by genotype BB (5,13 g.100g-1) {>} AB (5,08 g.100g-1) {>} AA (4,91 g.100g-1). Less significant effect was found on SNF (P{<}0,1). The highest average content of SNF was found in genotype BB (11,72 g.100g-1) {>} AA (11,62 g.100g-1) {>} AB (11,54 g.100g-1). In genotype AA was found the highest values of F, CP, CAS, SP, DM. Both genotypes AA, BB showed the same content of DM (16,32 g.100g-1).

O presente trabalho procurou investigar influência da presença de proteínas do soro do leite na atividade antioxidante da vanilina e ácido vanílico frente ao radical DPPH&bull; e a espécie de ferro hipervalente ferrilmioglobina MbFe(IV)=O em meio simulando o trato gastrointestinal. A constante de associação (KA) entre a vanilina e a &beta;-lactoglobulina (BLG) foi determinada utilizando-se as técnicas de espectroscopia de emissão molecular (KA = 400 &plusmn; 12&middot;102 L&middot;mol-1) e microcalorimétria (KA = 5,6&plusmn;0,3&middot;102 L&middot;mol-1) ambas em tampão fosfato com CH+ = 10-7,4 mol&middot;L-1 e força iônica 0,32 (NaCl). Para a interação entre a vanilina e albumina de soro bovino (BSA) encontrou-se o valor de 340 &plusmn; 13&middot;102 L&middot;mol-1 em meio de tampão fosfato com CH+ = 10-6,4 mol&middot;L-1 e força iônica 0,32 (NaCl), obtido por espectroscopia de emissão molecular. Constatou-se pela técnica de microcalorimetria que a complexação possui caráter exotérmico e as contribuições de interações hidrofóbicas para a complexação são fracas. A reatividade da vanilina e ácido vanílico com o radical DPPH&bull; foi investigada em meio de emulsão aquosa Tween-20&reg; com CH+ = 10-2,0 mol&middot;L-1. Os resultados obtidos demonstraram que a vanilina não pode ser considerada um bom antioxidante frente ao DPPH&bull; (k298 = 1,42&plusmn;0,04&middot;10-1 L&middot;mol-1&middot;s-1), no entanto, o ácido vanílico apresentou maior reatividade frente ao radical DPPH&bull; (k298 = 17,1&plusmn;0,3 &middot;10-1 L&middot;mol-1&middot;s-1). A presença das proteínas BLG e BSA nas reações de redução do radical DPPH&bull; pela vanilina e ácido vanílico conduziu a um efeito antagônico na constante de velocidade de reação. Os parâmetros termodinâmicos do estado de transição da reação com DPPH&bull; apresentaram valores relativamente altos de entalpia de ativação e moderados valores de entropia de ativação: &Delta;H&Dagger;298 = 34,0 &plusmn; 0,3 kJmol-1 para a vanilina e 46,2 &plusmn; 0,1 kJmol-1 no complexo com BSA e 51,0 &plusmn; 0,6 kJ&middot;mol-1 no complexo com BLG, valores negativos de entropia &Delta;S&Dagger;298 = -147,4 &plusmn; 0,9 J&middot;mol-1&middot;K-1, -105,3 &plusmn; 0,5 J&middot;mol-1&middot;K-1 e -90 &plusmn; 2 J&middot;mol-1&middot;K-1 respectivamente. Os valores de entalpia e entropia de ativação encontrados para o ácido vanílico foram: &Delta;H&Dagger;298= 19,6 &plusmn; 0,2 kJ&middot;mol-1, 10,2 &plusmn; 0,03 kJ&middot;mol-1 e 37,6 &plusmn; 0,3 kJ&middot;mol-1 para os complexos com BSA e BLG respectivamente e valores negativos de entropia &Delta;S&Dagger;298=-174 &plusmn; 0,5 J&middot;mol-1&middot;K-1, -206,0 &plusmn; 0,1 J&middot;mol-1&middot;K-1 e -116 &plusmn; 1 J&middot;mol-1&middot;K-1. A partir destes valores de entalpia e entropia de ativação o mecanismo de redução do radical DPPH&bull; foi atribuído a um processo de abstração de átomo de hidrogênio (HAT/PCET). A reação de desativação da espécie MbFe(IV)=O pela vanilina apresentou constante de velocidade de k298 = 57&plusmn;1 L&middot;mol-1&middot;s-1 sendo superior quando comparada ao ácido vanílico k298 = 15&plusmn;1 L&middot;mol-1&middot;s-1, fato este atribuído as cargas totais, negativa, do redutor e da proteína nas presentes condições experimentais. Observa-se um efeito antagônico da complexão da vanilina pelas proteínas na atividade antioxidante frente à ferrilmioglobina, onde o efeito reduziu, mas não impediu a reação de transferência de elétrons por esfera-externa à longa distância. Em contrapartida, a presença das proteínas BLG e BSA não influenciaram a reatividade do ácido vanílico frente à espécie MbFe(IV)=O. Os parâmetros de ativação encontrados para a reação de redução da MbFe(IV)=O com a vanilina apresentaram valores de &Delta;H&Dagger;298 = 58,8 &plusmn; 0,3 kJmol-1 e &Delta;S&Dagger;298 = -14 &plusmn; 1 J&middot;mol-1&middot;K-1, &Delta;H&Dagger;298 = 45,5 &plusmn; 0,3 kJ&middot;mol-1 e &Delta;S&Dagger;298 = -60 &plusmn; 1 J &middot;mol-1&middot;K-1, &Delta;H&Dagger;298 = 68,6 &plusmn; 0,4 kJ&middot;mol-1 e &Delta;S&Dagger;298 = 17 &plusmn; 1 J &middot;mol-1&middot;K-1 para vanilina \"livre\", complexo com BSA, e complexo com BLG respectivamente. Para a redução com ácido vanílico foram determinados os seguintes valores de entalpia e entropia de ativação: &Delta;H&Dagger;298 = 41,8 &plusmn; 0,2 kJ&middot;mol-1 e &Delta;S&Dagger;298 = -82,4 &plusmn; 0,7 J&middot;mol-1&middot;K-1, &Delta;H&Dagger;298 = 37,7 &plusmn; 0,3 kJ&middot;mol-1 e &Delta;S&Dagger;298 = -96 &plusmn; 1,0 J&middot;mol-1&middot;K-1, &Delta;H&Dagger;298 = 53,5 &plusmn; 0,2 kJ&middot;mol-1 e &Delta;S&Dagger;298 = -44 &plusmn; 1,0 J&middot;mol-1&middot;K-1 para vanilina \"livre\", complexo com BSA, e complexo com BLG respectivamente. / The present study evaluate the influence of the presence of whey proteins in the antioxidant activity of vanillin and vanillic acid towards the DPPH&bull; radical species and the hypervalent iron species ferrylmyoglobin, MbFe(IV)=O under conditions simulating the gastrointestinal tract. The association constant (KA) between vanillin and &beta;- lactoglobulin (BLG) was obtained using molecular emission spectroscopy (KA = 400 &plusmn; 12&middot;102 L&middot;mol-1) and microcalorimetric titration (KA = 5.6&plusmn;0.3&middot;102 L&middot;mol-1) both in phosphate buffer CH + = 10-7.4 mol&middot;L -1 and ionic strength 0.32 (NaCl). For the interaction between vanillin and bovine serum albumin (BSA) it was founded value of 340 &plusmn; 13&middot;102 L&middot;mol-1 in phosphate buffer with CH+ = 10-6,4 mol&middot;L-1 and ionic strength 0.32 (NaCl), as obtained by molecular emission spectroscopy. It was founded by microcalorimetry tritation that the complexation has a exothermic character and the contributions of hydrophobic interactions for complexation are weak. The reactivity of vanillin and vanillic acid toward DPPH&bull; radical was studied in aqueous emulsion using Tween-20&reg; with CH + = 10-2.0 mol&middot;L-1. The results show that vanillin can not be considered a good antioxidant (k298 = 1.42&plusmn;0.04&middot;10-1 L&middot;mol-1&middot;s-1), however vanillic acid show higher reactivity than vanillin towards the radical DPPH&bull; (k298 = 17.1&plusmn;0.3&middot;10-1 L&middot;mol-1&middot;s-1). The presence of the proteins BLG and BSA in the reduction reactions of the DPPH&bull; radical by vanillin and vanillic acid led to an antagonic effect in the reaction rate constant. The thermodynamic parameters for the transition state of the reaction with DPPH&bull; showed relatively high values of enthalpy of activation and moderately negative entropy of activation: &Delta;H&Dagger;298= 34.0 &plusmn; 0.3 kJmol-1 for vanillin and 46.2 &plusmn; 0.1 kJmol-1 for complex with BSA and 51.0 &plusmn; 0.6 kJ&middot;mol-1 for complex with BLG, negatives values of entropy &Delta;S&Dagger;298 = -147.4 &plusmn; 0.9 J&middot;mol-1&middot;K-1, -105.3 &plusmn; 0.5 J&middot;mol-1&middot;K-1 and -90 &plusmn; 2 J&middot;mol-1&middot;K-1 respectively. The values of enthalpy and entropy of activation found for vanillic acid were: &Delta;H&Dagger;298 = 19.6 &plusmn; 0.2 kJ&middot;mol-1, 10.2 &plusmn; 0.03 kJ&middot;mol-1 and 37.6 &plusmn; 0.3 kJ&middot;mol-1 for BSA and BLG respectively and negative values of entropy &Delta;S&Dagger;298 = -174 &plusmn; 0.5 J&middot;mol-1&middot;K-1, -206.0 &plusmn; 0.1 J&middot;mol-1&middot;K-1 and -116 &plusmn; 1 J&middot;mol-1&middot;K-1. From these values of enthalpy and entropy of activation the mechanism of radical DPPH&bull; reduction was assigned to a process of hydrogen atom transfer (HAT/PCET). The deactivation reaction of the MbFe(IV)=O species by vanillin shown rate constant of k298 = 57&plusmn;1 L&middot;mol-1&middot;s-1, which it is higher than vanillic acid k298 = 15&plusmn;1 L&middot;mol-1&middot;s-1. This fact is assigned to the total negative charges of the reductor and the protein under the experimental conditions. It is observed an antagonistic effect of the complexation of vanillin by proteins in the antioxidant activity, in which the effect diminish, but not avoid the long range electron transfer by out-sphere reaction. On the other hand, the presence of BLG and BSA do not affect the reactivity of vanillic acid towards the MbFe(IV)=O species. The activation parameters found for the reduction of MbFe(IV)=O by vanillin revealed values of &Delta;H&Dagger;298 = 58.8 &plusmn; 0.3 kJmol-1 and &Delta;S&Dagger;298 = -14 &plusmn; 1 J&middot;mol-1&middot;K-1, &Delta;H&Dagger;298 = 45.5 &plusmn; 0.3 kJ&middot;mol-1 e &Delta;S&Dagger;298 = -60 &plusmn; 1 J &middot;mol-1&middot;K-1, &Delta;H&Dagger;298 = 68.6 &plusmn; 0.4 kJ&middot;mol-1 and &Delta;S&Dagger;298 = 17 &plusmn; 1 J &middot;mol-1&middot;K-1 for free vanillin, complex with BSA and complex with BLG respectively. For the reduction by vanillic acid it were with the following values of enthalpy and entropy of activation: &Delta;H&Dagger;298 = 41.8 &plusmn; 0.2 kJ&middot;mol-1 and &Delta;S&Dagger;298 = -82.4 &plusmn; 0.7 J&middot;mol-1&middot;K-1, &Delta;H&Dagger;298 = 37.7 &plusmn; 0.3 kJ&middot;mol-1 and &Delta;S&Dagger;298 = -96 &plusmn; 1.0 J&middot;mol-1&middot;K-1, &Delta;H&Dagger;298 = 53.5 &plusmn; 0.2 kJ&middot;mol-1 and &Delta;S&Dagger;298 = -44 &plusmn; 1.0 J&middot;mol-1&middot;K-1 for free vanillin, complex with BSA and complex with BLG respectively.

O presente estudo teve como objetivo avaliar a associação entre o polimorfismo da &beta;-lactoglobulina e as características físico-químicas (pH, acidez e crioscopia), de composição (gordura, sólidos totais, uréia, proteína bruta, proteína verdadeira, nitrogênio não-protéico e caseína), e de estabilidade do leite. Para tanto, 11 rebanhos leiteiros foram selecionados, 5 da raça Holandesa e 6 da raça Girolanda, dos quais foram coletadas 4 amostras de leite de 164 vacas da raça Holandesa e 74 da raça Girolanda, sendo duas coletas realizadas na estação das secas e 2 na estação das chuvas. Cada amostra foi submetida à análise de composição e de características físico-químicas. Para a identificação do genótipo para &beta;-lactoglobulina, foram coletadas amostras de sangue de cada vaca, as quais foram submetidas à reação de polimerase em cadeia (PCR), determinando-se as freqüências alélicas e genotípicas dos animais. A estabilidade do leite foi avaliada pelo teste de estabilidade ao etanol, nas seguintes concentrações alcoólicas: 70, 76, 80 e 84ºGL. As freqüências genotípicas foram 0,28, 0,30 e 0,41 para os genótipos AA, AB e BB, respectivamente. A freqüência do alelo B foi maior que do alelo A, 0,52 e 0,47, para a raça Holandesa, e 0,58 e 0,41, para a raça Girolanda, respectivamente. Não houve efeito do polimorfismo da &beta;-lactoglobulina (AA, AB e BB), entre os animais das raças, avaliadas sobre as propriedades físico-químicas e a composição do leite. Observou-se efeito de raça (Holandesa e Girolanda, respectivamente) sobre a acidez titulável (16,16 e 17,07°D) e pH (6,78 e 6,75), e de composição do leite quanto as variáveis gordura (3,31 e 3,20%), NUL (16,62 e 14,45mg/dL) e PB (3,13 e 3,04%). Houve efeito da estação (chuvosa e seca, respectivamente) sobre as características físico-químicas de acidez titulável (16,62 e 16,34°D), pH (6,76 e 6,79) e crioscopia (-0,5411 e -0,5376°H), e de composição do leite quanto as variáveis lactose (4,34 e 4,50%), sólidos totais (11,65 e 11,90%), LogCCS (2,44 e 2,34), PB (3,08 e 3,14%), PV (2,84 e 2,91%), caseína (2,01 e 2,13%) e relação caseína:proteína verdadeira (0,70 e 0,72). Verificou-se também efeito da raça e estação do ano sobre a estabilidade do leite, sendo que o leite foi mais instável para raça Girolanda e durante a estação seca, mas não se observou efeito do polimorfismo da &beta;-lactoglobulina sobre esta característica. / The objective of this study was to evaluate the association between beta-lactogobulin polymorphism and physico-chemical characteristics, composition (fat, total solids, urea, crude protein, true protein, non protein nitrogen and casein), and stability of milk. For this aim, 11 dairy herds were selected, six of them composed of crossbred Holstein-Zebu (H-Z) cows and five from Holstein cows. Milk samples were taken four times (twice in dry season and twice in rainy season), from 278 Holstein and 156 crossbred Holstein-Zebu cows. Individual milk samples were analyzed for milk composition and physico-chemical properties. For &beta;-lactoglobulin polymorphism analysis, 10 mL of blood samples were ollected from each cow and then submitted to polymerase chain reaction (PCR). Following &beta;-lactoglobulin protein variants detection, genotype and allele frequencies for the 11 herds were analyzed. Heat stability of milk was determined by the alcohol-induced precipitation test, using the following ethanol concentrations 70, 76, 80 and 84ºGL. The genotype frequencies were 0.28, 0.30 and 0.41 for AA, AB and BB, respectively. Allele B frequency was higher than A, 0.52 and 0.47, for Holstein cows, 0.58 and 0.41, for Holstein-Zebu, respectively. Genetic variants of &beta;-lactoglobulin (AA, AB and BB) had no effect on physico-chemical (acidity, pH and crioscopy), and compositional characteristics (fat, total solids, urea, crude protein, non-protein nitrogen, true protein and casein percentages), either among milk from Holstein cows, or from crossbred Holstein-Zebu. Breed effect for Holstein and H-Z on titrable acidity (16,16 and 17,07°D, respectively), pH (6,78 and 6,75, respectively), fat (3,31e 3,20%, respectively), milk urea nitrogen (16,62 e 14,45mg/dL, respectively) and crude protein (3,13 e 3,04%, respectively) could be observed. Effect of seasonality between rainy and dry seasons was also observed on physico-chemical variables of titrable acidity (16,62 and 16,34°D, respectively), pH (6,76 and 6,79, respectively) and freezing point (-0,5411and -0,5376°H, respectively), and on composition characteristics of lactose (4,34 and 4,50%, respectively), total solids (11,65 and 11,90%, respectively), LogCCS (2,44 and 2,34, respectively), crude protein (3,08 and 3,14%, respectively), true protein (2,84 and 2,91%, respectively), casein content (2,01 and 2,13%, respectively) and casein:true protein ratio (0,70 and 0,72, respectively). Effect of breed and seasonality on milk ethanol stability test was observed. Holstein-Zebu milk was ethanol-unstable on dry season. No effect of &beta;-lactoglobulin on milk stability was observed.

Le développement de l’allergie peut être influencé par le microbiote intestinal qui est impliqué dans la maturation du système immunitaire de l’hôte lors de la colonisation du tractus digestif dès la naissance. L’objectif de mon travail a été d’étudier l’impact du microbiote intestinal sur le développement d’une sensibilisation allergique à des protéines de lait de vache à l’aide d’un modèle de souris BALB/c gnotoxéniques. Dans une première étude, nous avons montré que les souris axéniques (Ax, sans germe) sont plus réactives que les souris conventionnelles (CV) au potentiel immunogénique et allergénique de la β-lactoglobuline (BLG) et de la caséine (CAS), lorsque ces deux protéines sont injectées intrapéritonéalement sans adjuvant. A l’aide d’un autre modèle de sensibilisation par voie orale au lait, nous avons confirmé que les souris Ax développent des réponses IgE contre la BLG plus fortes que celles des souris CV. Les mécanismes de sensibilisation contre la BLG et la CAS sont alors différemment affectés par la présence ou non d’un microbiote intestinal. Par ailleurs, une colonisation tardive du tractus digestif de souris Ax à l’âge de 6 semaines par le microbiote de souris CV induit chez les souris conventionnalisées (CVd) le développement, après sensibilisation, de réponses humorales toujours plus fortes que celles observées chez les souris CV. A l’inverse, une conventionnalisation des souris Ax au moment du sevrage à l’âge de 3 semaines, induit un niveau de sensibilisation plus faible que celui des souris CV. Dans ce cas, des différences de composition du microbiote intestinal entre souris CV et CVd pourraient jouer un rôle dans le faible niveau de sensibilisation des souris CVd. Nous avons enfin évalué l’impact de l’implantation dès la naissance d’une souche de Lactobacillus casei en monoxénie (souris Mx). La réponse humorale contre la CAS, mais pas contre la BLG, est alors significativement plus élevée chez les souris Mx que chez les souris Ax. Ces différentes études suggèrent que l’influence du microbiote sur le développement d’une sensibilisation aux protéines du lait de vache diffère selon les allergènes et selon le mode d’exposition aux allergènes. Ces résultats soulignent également qu’un retard de colonisation du tractus digestif peut perturber durablement la réactivité du système immunitaire à une sensibilisation contre des antigènes alimentaires. / The development of allergic responses can be influenced by the gut microbiota, which critically stimulates the maturation of the host immune system during colonization of the digestive tract at birth. We thus aimed to study the impact of the gut microbiota on the development of an allergic sensitization to cow's milk proteins by using a gnotobiotic BALB/c mouse model. First, we showed that germ-free (GF) mice are more responsive than conventional mice (CV) to the immunogenic and allergenic potential of β-lactoglobulin (BLG) and casein (CAS) when these proteins are injected intraperitoneally without adjuvant. With another model of oral sensitization to cow’s milk, the development of higher BLG-specific IgE responses in GF mice compared to CV mice was confirmed. We also observed that the mechanisms leading to oral sensitization to BLG and CAS are differentially affected by the absence of gut microbiota. Furthermore, a delayed colonization of the digestive tract of 6-week-old GF mice by a conventional microbiota was studied. The conventionalized mice (CVd) still developed, after sensitization, higher antibody responses than those measured in CV mice. In contrast, GF mice conventionnalized just after weaning, at 3 week of age, displayed a level of sensitization lower than that of CV mice. Differences in the gut microbiota composition evidenced between CVd and CV mice could also play a role in the lower level of sensitization of CVd mice. Finally, we evaluated the impact of the neonatal mono-colonization of mice by a strain of Lactobacillus casei. The antibody responses against CAS, but not against BLG, were then significantly higher in mono-associated mice than in GF mice. These studies suggest that the influence of microbiota on the development of sensitization to cow's milk proteins depends on the nature of the allergens and the mode of exposure. These results also underline that delayed bacterial colonization altered persistently the host immune response to oral sensitization against food antigens.