No abstract

The objectives of this study were (1) to assess the effect of a denatured whey protein concentrate (DWPC) and its fractions on cheese yield, composition, and rheological properties, and (2) to separate the direct effect of the DWPC or its fractions on cheese rheological properties from the effect of a concomitant increase in cheese moisture. Semihard cheeses were produced at a laboratory scale, and mechanical properties were characterized by dynamic rheometry. Centrifugation was used to induce a moisture gradient in cheese to separate the direct contribution of the DWPC from the contribution of moisture to cheese mechanical properties. Cheese yield increased and complex modulus (G*) decreased when the DWPC was substituted for milk proteins in milk. For cheeses with the same moisture content, the substitution of denatured whey proteins for milk proteins had no direct effect on rheological parameters. The DWPC was fractionated to evaluate the contribution of its different components (sedimentable aggregates, soluble component, and diffusible component) to cheese yield, composition, and rheological properties. The sedimentable aggregates were primarily responsible for the increase in cheese yield when DWPC was added. Overall, moisture content explained to a large extent the variation in cheese rheological properties depending on the DWPC fraction. However, when the effect of moisture was removed, the addition of the DWPC sedimentable fraction to milk increased cheese complex modulus. Whey protein aggregates were hypothesized to act as active fillers that physically interact with the casein matrix and confer rigidity after pressing.

No abstract

No abstract

Summary Pesticides might cause health problems and must be thoroughly controlled in food. The aim of this study was to determine, on dry basis, the dissipation of active material in sixteen pesticides for wheat production (eleven fungicides; two herbicides; three insecticides) after heating in water, flat dough (crackers) and leavened dough (pan bread); the effect of dough alkalinity was also checked. Compared to water, dough protected pesticides from heat. Malathion, an insecticide, was easily dissipated by heat but most pesticides, especially fungicides, were very stable to dough fermentation and bread baking. With a few exceptions, similar trends were seen in neutral and alkaline crackers. We conclude that it is unlikely that baking would dissipate much pesticides residues, especially fungicides, in flat and leavened dough for crackers and pan bread.