Functionality of process cheese made from Cheddar cheese with various rennet levels and high-pressure processing treatments.

Due to its versatility and shelf stability, process cheese is gaining interest in many developing countries. The main structural component (base) of most processed cheese formulations is young Cheddar cheese that has high levels of intact casein. Exporting natural Cheddar cheese base from the United States to distant overseas markets would require the aging process to be slowed or reduced. As Cheddar cheese ripens, the original structure is broken down by proteolysis and solubilization of insoluble calcium phosphate. We explored the effect of varying rennet levels (we also used a less proteolytic rennet) and application of high-pressure processing (HPP) to Cheddar cheese, as we hoped these treatments might limit proteolysis and concomitant loss of intact casein. To try to retain high levels of insoluble Ca, all experimental cheeses were made with a high-draining pH and from concentrated milk. To compare our intact casein results with current practices, we manufactured a Cheddar cheese that was prepared according to typical industry methods (i.e., use of unconcentrated milk, calf chymosin [higher levels], and low draining pH value [∼6.2]). All experimental cheeses were made from ultrafiltered milk with protein and casein contents of ∼5.15% and 4.30%, respectively. Three (low) rennet levels were used: control (38 international milk clotting units/mL of rennet per 250 kg of milk), and 25% and 50% reduced from this level. All experimental cheeses had similar moisture contents (∼37%) and total Ca levels. Four days after cheese was made, half of the experimental samples from each vat underwent HPP at 600 MPa for 3 min. Cheddar cheese functionality was monitored during aging for 240 d at 4°C. Cheddar cheese base was used to prepare process cheese after aging for 14, 60, 120, 180, and 240 d. Loss tangent (LT) values of cheese during heating were measured by small strain oscillatory rheology. Intact casein levels were measured using the Kjeldahl method. Acid or base titrations were used to determine the buffering capacity and insoluble Ca levels as a percentage of total Ca. The LTmax values (an index of meltability) in process cheese increased with aging for all the cheese bases; the HPP treatment significantly decreased LTmax values of both base (natural) and process cheeses. All experimental cheeses had much higher levels of intact casein compared with typical industry-make samples. Process cheese made from the experimental treatments had visually higher stretching properties than process cheese made from Cheddar with the typical industry-make procedure. Residual rennet activity was not affected by rennet level, but the rate of proteolysis was slightly slower with lower rennet levels. The HPP treatment of Cheddar cheese reduced residual rennet activity and decreased the reduction of intact casein levels. The HPP treatment of Cheddar cheese resulted in process cheeses that had slightly higher hardness values, lower LTmax values, and retained higher storage modulus values at 70°C. We also observed that the other make procedures we used in all experimental treatments (i.e., using a less proteolytic chymosin, using a concentrated cheese milk, and maintaining a high draining pH value) had a major effect on retaining high levels of intact casein.

Crystallization and preliminary characterization of crystals of R-alcohol dehydrogenase from Lactobacillus brevis.

The R-specific alcohol dehydrogenase (RADH) from Lactobacillus brevis is a valuable catalyst for the production of chiral alcohols that can be used as synthons in asymmetric syntheses. RADH is a homotetramer with 222 symmetry and a molecular mass of 107 kDa. The recombinant enzyme has been expressed in Escherichia coli, purified to homogeneity and crystallized. The crystals belong to the orthorhombic space group I222, with unit-cell parameters a = 56.5, b = 85.1, c = 115.4 A, and diffract X-rays to at least 1.8 A resolution. The calculated crystal packing parameter V(M) = 2.59 A(3) Da(-1), corresponding to a solvent content of 52.5% and suggesting that one RADH monomer is contained in the asymmetric unit. The RADH tetramer lies on a special position with its molecular dyads coinciding with the crystallographic twofold axes and with its centre of mass on the origin of the unit cell.

[Acne fulminans following use of anabolic steroids]. / Acne fulminans nach Anabolikaeinnahme.

The main stimulant for the use of anabolic agents by competitive athletes is their effect on the quantity, structure, and power of the muscles, although an actual increase in efficiency is most doubtful. This effect has to be purchased with a number of possible side effects including acne or acneiform lesions - an interesting aspect from the dermatologic point of view, since androgens may have an etiopathogenetic significance in this disease. We report on a 23-year-old male patient (competitive javelin thrower) who developed acne fulminans while using anabolics and vitamin B preparations. The temporal correlation between the onset of the skin lesions and the intake of the drugs suggests that the drugs - either alone or in combination - may be responsible for the skin eruptions. We discuss the case in detail referring to the literature.