Ripening of Camembert-type cheese made from caprine milk using calf rennet or kid rennet as coagulant

Camembert-type cheese was made from caprine milk using either calf rennet or kid 'Grandine' rennet as coagulant. The pH of all cheeses increased throughout ripening and levels of pH 4.6-soluble nitrogen increased from 8.1 to 18.2% of total nitrogen (TN) and from 6.9 to 20% TN for the cheeses made using calf rennet and kid rennet, respectively. Degradation of β-casein, measured by urea–polyacrylamide gel electrophoresis, and total and free amino acids were greater in the cheese made using kid rennet. Production of peptides, analysed by high performance liquid chromatography (HPLC), was slightly more extensive in the Camembert-type cheese made using calf rennet as coagulant. In general, a higher degree of proteolysis was found in Camembert-type cheese made from caprine milk using kid rennet than in cheese made using calf rennet as coagulant.     

MUSCLE AND ROE LIPID COMPOSITION IN DIPLOID AND TRIPLOID SCALLOPS

The use of triploid bivalves is now common in the market. We tested if there was a difference in lipid and long-chain highly unsaturated fatty acid (HUFA) accumulation in the muscle of diploid and triploid scallops ( Argopecten ventricosus ) during maturation, as triploids do not reproduce and lipids are not transferred to the gonad, and thus, could be accumulated in the meat (adductor muscle). Differences in triacylglycerols, phospholipids, esterified and free sterols, as well as HUFA in the reserves of gonads were found between diploid and triploid scallops. In contrast, no differences were found in the muscle for any of the lipid classes or fatty acid content in relation to ploidy, although they varied in relation to the sampling month.

PRACTICAL APPLICATIONS

The results obtained indicate that for human consumption purposes, the quality of the meat and roe of scallops follows a temporal pattern of lipid accumulation, with higher levels of total sterols in summer, but a higher proportion of arachidonic acid in winter and lower docosahexaenoic acid in autumn, and that the muscle lipid composition is not affected by the triploid condition.     

The effect of use of freeze-thawed pork on the properties of Bologna sausages with two fat levels

The rheological characteristics, microstructure and thermal stability of meat emulsions, made with two levels of fat (7.6% and 20.3%) and prepared from either fresh meat or meat subjected to one or three freeze-thaw cycles, were measured. Lower fat contents were accompanied by a significant reduction in the binding property, shear force and hardness of the products. Both low fat and use of freeze-thawed meat produced structures with a less dense matrix, freeze-thawing altered the microstructure of the meat sausages and reduced shear force, hardness, chewiness and thermal stability. These effects were particularly apparent in the higher-fat product.     

Determination of OH Extinction Coefficients in R2O-B2O3-SiO2 Glasses (R = Li, Na, K)

Infrared spectra of glasses of the system R₂O-B₂O₃-SiO₂ were investigated. The extinction coefficients of the hydroxyl absorption band ("free OH") were calculated by a method proposed for alkali borate glasses. The results confirmed the applicability of this method to homogeneous and phase-separated alkali borosilicate glasses. The variation of the hydroxyl absorption band position was interpreted according to the structural characteristics of the studied glasses.     

SCALE UP ISOLATION OF IMMUNOGLOBULINS FROM PIG SERUM BY IMMOBILIZED METAL AFFINITY CHROMATOGRAPHY

The immunoglobulins (Ig's) are proteins with a well-known structure and function. In immunocompetent animals (individuals), these proteins counteract the pathogenic microorganisms. However, under pathological conditions or in a precocious weaning, exogenous immunoglobulins, among other treatments, are being used to avoid and cure some diseases. There is much interest in developing alternative methods for the isolation of functional immunoglobulins from sources different than maternal colostrum and milk. Pig serum contains a high concentration of Ig's and it has the advantage of containing not only IgG but also IgA and IgM in a greater proportion than found in any other species. Pig serum is a major contaminant generated by meat producers that could be used as a biotechnological alternative for blood or milk whey. Immunoglobulins G, A and M were isolated from porcine serum using Nickel-Iminodiacetate-Sepharose 6B in a single step at an analytical level. The procedure was easily scaled up to a 30 ml bed column. Serum immunoglobins (176 ml; 8.7 g) were adsorbed to the gel in buffer, pH 6.0, containing 1.0 M NaCl, and the purified immunoglobulins (735 mg) were eluted using the same buffer, but at pH 5.0. This separation was repeated 27 times without loss of gel capacity. The source of immunoglobulins, the longevity of the adsorbent, the gel capacity (29 mg/ml bed volume) and the mild conditions allowed rapid isolation of high concentrations of immunoglobulins. This method can serve as an alternative to those currently available for obtaining the three major immunoglobulins for inclusion in animal feeding.