Effect of substituting whey cream for sweet cream on the textural and rheological properties of cream cheese.

In the manufacture of cream cheese, sweet cream and milk are blended to prepare the cream cheese mix, although other ingredients such as condensed skim milk and skim milk powder may also be included. Whey cream (WC) is an underutilized fat source, which has smaller fat droplets and slightly different chemical composition than sweet cream. This study investigated the rheological and textural properties of cream cheeses manufactured by substituting sweet cream with various levels of WC. Three different cream cheese mixes were prepared: control mix (CC; 0% WC), cream cheese mixes containing 25% WC (25WC; i.e., 75% sweet cream), and cream cheese mixes with 75% WC (75WC; i.e., 25% sweet cream). The CC, 25WC, and 75WC mixes were then used to manufacture cream cheeses. We also studied the effect of WC on the initial step in cream cheese manufacture (i.e., the acid gelation process monitored using dynamic small amplitude rheology). Acid gels were also prepared with added denatured whey proteins or membrane proteins/phospholipids (PL) to evaluate how these components affected gel properties. The rheological, textural, and sensory properties of cream cheeses were also measured. The WC samples had significantly higher levels of PL and insoluble protein compared with sweet cream. An increase in the level of WC reduced the rate of acid gel development, similar to the effect of whey phospholipid concentrate added to mixes. In cream cheese, an increase in the level of added WC resulted in significantly lower storage modulus values at temperatures <20°C. Texture results, obtained from instrumental and sensory analyses, showed that high level of WC resulted in significantly lower firmness or hardness values and higher stickiness compared with cream cheeses made with 25WC or CC cream cheeses. The softer, less elastic gels or cheeses resulting from the use of high levels of WC are likely due to the presence of components such as PL and proteins from the native milk fat globule membrane. The use of low levels of WC in cream cheese did not alter the texture, whereas high levels of WC could be used if manufacturers want to produce more spreadable products.

Behavior of stabilizers in acidified solutions and their effect on the textural, rheological, and sensory properties of cream cheese.

Stabilizers are routinely added during cream cheese manufacture to help prevent syneresis during storage. We investigated how different types of stabilizers affected the texture, rheology, and sensory properties of cream cheese. Cream cheeses were manufactured with 0.33% xanthan gum (XG), locust bean gum (LBG), guar gum (GG), or a combination (CBN) of these 3 stabilizers (0.11% of each). Rheological properties of solutions of the individual stabilizers and their combination (equal amounts) were also determined under conditions similar to the aqueous phase of cream cheese (0.6% gum, 1.8% NaCl, and pH 5). Dynamic small amplitude rheological properties of the cream cheeses were measured during heating from 5 to 80°C at the rate of 1°C/min and cooling at the same rate (because most cream cheese is hot packed/filled before cooling). Measured rheological parameters included storage modulus (G') and loss tangent. Hardness of cream cheeses was determined by texture profile analysis. Quantitative spectrum descriptive sensory analysis was also performed. Distinct differences were observed between the rheological properties of solutions of the individual stabilizers and the CBN containing all the stabilizers. Results showed that CBN solution formed a strong, thermally reversible gel due to synergistic interaction between stabilizers, whereas XG solution formed a weak gel that was not greatly affected by temperature. Solutions of LBG and GG behaved rheologically as entangled polymer solutions. In the high-temperature (>35°C) region, cream cheeses made with XG and CBN showed higher G' values compared with other cream cheeses. The G' values were higher for XG- and CBN-stabilized cream cheeses than LBG- and GG-stabilized cream cheeses at several temperature regions during the cooling cycle. The CBN-stabilized cream cheeses had higher hardness values than the cream cheeses manufactured with the individual stabilizers. Differences were observed between the sensory attributes of cream cheeses stabilized with CBN and those made with individual stabilizers. At low temperatures, the higher hardness and G' values of CBN-stabilized cream cheeses could be due to synergistic interaction between XG and galactomannans. The higher elasticity of XG-stabilized cream cheeses at high temperatures could be due to its higher thermal stability. This study showed that the stabilizers added during manufacture of cream cheese affected its texture, rheological, and sensory properties.

Effects of processing conditions on the texture and rheological properties of model acid gels and cream cheese.

Manufacture of cream cheese involves the formation of an initial acid-induced gel made from high-fat milk, followed by a series of processing steps including shearing, heating, and dewatering that complete the conversion of the acid gel into a complex cheese product. We investigated 2 critical parameters for their effect on the initial gel: homogenization pressure (HP) of the high-fat cheese milk, and fermentation temperature (FT). The impact of a low (10 MPa) and high (25 MPa) HP, and low (20°C) and high (26°C) FT were investigated for their effects on rheological and textural properties of acid-induced gels. Intact acid gels were sheared and heated to 80°C, and then their rheological properties were analyzed to help understand the effect of shearing/heating processes on the gel characteristics. The effect of HP on fat globule size distribution and the amount of protein not involved in emulsion droplets (i.e., in the bulk phase) were also studied. For cream cheese trials, a central composite experimental design was used to explore the effect of these 2 parameters (HP and FT) on the texture, rheology, and sensory properties of experimentally manufactured cream cheese. Storage modulus (G') and hardness values of cream cheeses were obtained from small amplitude oscillatory rheology tests and texture profile analysis, respectively. Quantitative spectrum descriptive sensory analysis was also performed. Consistency of acid gels (measured using a penetration test) increased with an increase in FT and with an increase in HP. Although stiffer acid-induced gels were formed at high FT, after the heating and shearing processes the apparent viscosity of the samples formed at high FT was lower than those formed at low FT. For the cream cheeses, significant prediction models were obtained for several rheological and textural attributes. The G' values at 8°C, instrumental hardness, and sensory firmness attributes were significantly correlated (r > 0.84); all these attributes significantly decreased with an increase in FT, and HP was not a significant parameter in the prediction models developed for these attributes. Significant interactions were observed between the HP and FT terms for these prediction models. Higher HP increased the amount of protein adsorbed at interface of fat globules but decreased bulk phase protein content (which may be important for crosslinking this gelled emulsion system). At higher FT temperature, coarser gel networks were likely formed. The combined effect of a coarser acid gel network at high FT, and less bulk phase casein available for crosslinking the acidified emulsion gel with an increase in HP, could have contributed to the lower stiffness/firmness observed in cream cheese made under conditions of both high FT and high HP. Stickiness of cream cheese greatly increased under conditions of high FT and high HP, whereas the sensory attributes cohesiveness of mass and difficulty to dissolve decreased. This study helped to better understand the complex relationships between the initial acid-induced gel phase and properties of the (final) cream cheese.

An improved predictive model to determine the thermal degradation of lignocellulosic materials at low temperature (Torrefaction) ranges.

This study introduces an improved computational procedure to determine the thermal degradation of biomasses when submitted to a torrefaction process. The novelty consists in integrating a summative kinetic model approach with an enhanced finite difference scheme. This is achieved by defining timing updated parameters to account for both the extent of conversion and the evolution of the fibers composition. As main result, the proposed method enhances the exploitation of the summative assumption considering that the predictive accuracy of the model sets within 5% as maximum error. Furthermore, the adopted discrete approach contributes to generalize the TGA set up going beyond the conventional heating programs usually limited to isothermal and constant heating rate constrains. Due to these constitutive improvements, the proposed computational approach looks promising for investigations involving both kinetic analysis and thermal processes design including torrefaction.

A PHACES syndrome unmasked by propranolol interruption in a tetralogy of Fallot patient: case report and extensive review on new indications of beta blockers.

Infantile hemangiomas (IHs) are the most common benign tumors of infancy and usually they don't require specific therapy. In 10-20% of cases IHs are able to generate complication and medical/surgical intervention is needed. For many decades standard treatment consisted in oral or intralesional corticosteroids until Leaute-Labreze and colleagues published the first report on the efficacy of propranolol for cutaneous infantile hemangiomas in 2008. IHs can be sometimes part of complex syndrome. Here we report the case of a patient with tetralogy of Fallot operated at 5 month of age who stopped propranolol treatment for hypoxic spells and unusually developed facial and subglottic IHs configuring the diagnosis of PHACES syndrome (posterior fossa brain malformations, hemangioma, arterial anomalies, cardiac defects and/or aortic coarctation, ocular anomalies and sternal defects). To our knowledge this is the first report in the international literature of a delayed appearance of an infantile hemangioma involving the skin and the airways (PHACES syndrome). The pathophysiological explanation relies on the mechanism of action of propranolol which seems to act initially with vasoconstriction, down-regulating proangiogenetic factors and inducing endothelial cell apoptosis. Many decades since their introduction ß-blockers are useful in a growing group of diseases. The pleiotropic effect of ß-adrenoceptors antagonists is not yet deeply understood, residing in neurohormonal regulation systems and angiogenesis and proving to be an effective treatment from cardiovascular to oncological illnesses.

Characterization of the rheological, textural, and sensory properties of samples of commercial US cream cheese with different fat contents.

In this study, 18 commercial samples of cream cheeses from the United States, including full-fat, Neufchatel or one-third less fat, and fat-free cheeses were analyzed for their rheological, textural, and sensory properties. Dynamic rheological properties were measured by small-amplitude oscillatory rheology during heating from 5 to 80 degrees C and cooling from 80 to 5 degrees C. The parameters measured were storage modulus (G') and loss tangent (LT). Hardness of cream cheeses was determined by penetration and spreadability tests with a texture analyzer. Quantitative descriptive sensory analysis was performed by a trained panel to determine textural properties including firmness, stickiness, cohesiveness of mass, gumminess, difficulty to dissolve, particle size, and difficulty to spread. Principal component analysis of sensory and instrumental parameters was performed to identify relationships between these different parameters and to group samples with similar characteristics. A standard recipe for preparation of cheesecakes was used to test the influence of type of cream cheese on cake properties. Hardness of cheesecakes was also determined by penetration. Most full-fat cream cheeses showed significantly greater G' values than the Neufchatel or fat-free cheeses at temperatures below 25 degrees C during the heating cycle. For the cheeses containing fat (full fat and Neufchatel), G' values steeply decreased during heating up to 40 degrees C; the decrease was greater for full-fat cream cheese compared with Neufchatel cheeses. In full-fat cream cheese, one maximum in the LT profile was observed during heating at temperatures below 40 degrees C. In Neufchatel cheeses, a smaller maximum in LT was observed at temperatures below 40 degrees C, whereas fat-free cream cheeses showed no noticeable maximum LT in this temperature region. Most full-fat cream cheeses had greater values of hardness as determined by penetration or spreadability compared with Neufchatel or fat-free cheeses. Sensory analysis indicated that full-fat cream cheeses were firmer, more cohesive, more difficult to dissolve and spread, and less sticky than Neufchatel or fat-free cheeses. The high hardness of full-fat cream cheese is presumably due to its greater fat content because after homogenization of the cream cheese mix, fat globules are partly covered with casein and participate in the aggregation of casein particles, reinforcing the structure of this product. These results indicate that there are significant differences in the textural properties of cream cheese made with different fat contents.

Reversible cerebral ischemias: a comparative analysis of risk factors in TIAs and in RINDs.

A retrospective study in which 709 patients, 522 with RIND and 187 with TIA, were compared in respect of common risk factors (RFs) for acute cerebrovascular disease. The two forms of the disease differed significantly in respect of smoking, hematocrit, hypercholesteremia, hypertriglyceridemia and hyperuricacidemia. Although these RFs do not seem to be determinants of or discriminants between the two forms of acute cerebrovascular disease, it is nonetheless highly probable that, together with all the other RFs, they have a facilitatory role.