Composition, yield, and functionality of reduced-fat Oaxaca cheese: effects of using skim milk or a dry milk protein concentrate.

The effect of adding either skim milk or a commercial dry milk protein concentrate (MPC) to whole milk on the composition, yield, and functional properties of Mexican Oaxaca cheese were investigated. Five batches of Oaxaca cheeses were produced. One batch (the control) was produced from whole milk containing 3.5% fat and 9% nonfat solids (SNF). Two batches were produced from milk standardized with skim milk to 2.7 and 1.8% fat, maintaining the SNF content at 9%. In the other 2 batches, an MPC (40% protein content) was used to standardize the milk to a SNF content of 10 and 11%, maintaining the milk fat content at 3.5%. The use of either skim milk or MPC caused a significant decrease in the fat percentage in cheese. The use of skim milk or MPC showed a nonsignificant tendency to lower total solids and fat recoveries in cheese. Actual, dry matter, and moisture-adjusted cheese yields significantly decreased with skim milk addition, but increased with MPC addition. However, normalized yields adjusted to milk fat and protein reference levels did not show significant differences between treatments. Considering skim milk-added and control cheeses, actual yield increased with cheese milk fat content at a rate of 1.34 kg/kg of fat (R=0.88). In addition, cheese milk fat and SNF:fat ratio proved to be strong individual predictors of cheese moisture-adjusted yield (r(2) ≈ 0.90). Taking into account the results obtained from control and MPC-added cheeses, a 2.0-kg cheese yield increase rate per kg of milk MPC protein was observed (R=0.89), with TS and SNF being the strongest predictors for moisture adjusted yield (r(2) ≈ 0.77). Reduced-fat Oaxaca cheese functionality differed from that of controls. In unmelted reduced-fat cheeses, hardness and springiness increased. In melted reduced-fat cheeses, meltability and free oil increased, but stretchability decreased. These changes were related to differences in cheese composition, mainly fat in dry matter and calcium in SNF.

Fat and sodium chloride reduction in sausages using kappa-carrageenan and other salts.

Fat and sodium chloride were reduced in a sausage formulation including kappa-carrageenan and other salts, as potassium and calcium chloride, in different concentrations, in order to compensate the ionic strength during myofibrillar protein extraction and solubilisation, and to promote the carrageenan stable conformation and gelation. Four different treatments were employed reducing fat from 15 to 10% and sodium chloride from 2.5 to 1.5% and 1%. Potassium chloride was added at 0.5% to all the treatments, and calcium chloride to 0.5% and 0.01% in the last two. The cooking yield was higher for all the treatments but expressible moisture was not significantly different, meaning that the water is not chemically entrapped by carrageenan at the ionic strength conditions employed. However, since no detrimental cooking losses or fat release were detected, myofibrillar proteins maintain a good functionality at these conditions together with kappa-carrageenan. Low-fat sodium-reduced treatment results were slightly darker but redder than the control, probably due to less fat in the formulation. Textural profile analysis demonstrated that, at the fat level employed and the different sodium, potassium and calcium chloride concentrations, similar textures could be created. Sensory analysis indicated that from the formulations employed, 1.5% NaCl with 0.5% KCl and 0.01% CaCl(2) was similar in controlling flavour (juiciness) and texture (hardness). These results established the possibility to reduce significantly the fat and sodium chloride content employing kappa-carrageenan with potassium and calcium chloride, without detrimental effects on texture and sensory characteristics.