William J. Reville

Composition, microstructure and maturation of semi-hard cheeses from high protein ultrafiltered milk retentates with different levels of denatured whey protein

Abstract Standardized milks, heated at 72–100 °C to denature ~5–63% of the whey protein, were ultrafiltered to yield retentates with protein and fat levels of ~18.5 and 14%, respectively. Retentates were converted into semi-hard cheeses using specialized coagulation and gel-cutting equipment, with scalding and further syneresis being carried out in conventional cheese vats. High heat treatment of milk necessitated an increase in set temperature, a reduction in set pH and higher scalding temperatures in the cheese vat. Cheese from milk heated at 72 °C for 15 s had a mean composition of ~39.8% moisture, 28% protein, 45.1% fat-in-dry matter, 3.5% salt-in-moisture ( S M ) and an ex-brine (1 day) pH of 5.27. Increasing levels of whey protein denaturation (WPD) resulted in cheeses having higher moisture, S M , and whey protein levels, lower ex-brine pH values and lower rates of pH increase during a 182-day ripening period. Cheeses with high levels of WPD also showed poorer curd fusion and lower yield (fracture) values during ripening. Higher levels of denatured whey protein in cheese were associated with a higher degree of primary proteolysis. However, the levels of small peptides (

Textural and ultrastructural changes during processing and storage of lightly preserved salmon (Salmo salar) products

The effect of a controlled lactic fermentation on textural and ultrastructural properties of salmon fillets was evaluated. When compared with a non-inoculated cured sample, fermented salmon had unique textural properties since it exhibited significantly higher force (p < 0.05) and work (p < 0.001) values in a penetration test on two sampling days but a consistently lower hardness (p < 0.05) in a Texture Profile Analysis (TPA) rheological test. Study of the myofibrillar ultrastructure showed that basic structures were drastically damaged during processing and storage of fermented and cured salmon. Nevertheless, Z-lines were better preserved in fermented samples. It is suggested that the slight protective effect of lactic fermentation with the starter L sake may be the consequence of a lower pH, by putatively inhibiting neutral or alkaline proteolytic enzymes. © 2000 Society of Chemical Industry

Effects of microencapsulated high-fat powders on the empirical and fundamental rheological properties of wheat flour doughs

ABSTRACT Microencapsulated high-fat powders are a healthy and convenient alternative to fats normally used in cereal-based products. In powder form they are easier to use than block fat. Microencapsulation involves dispersion of the fat using homogenization. The globules are then fixed by spray-drying. Empirical and fundamental rheological tests were conducted on doughs containing commercial vegetable fat and four microencapsulated high-fat powders. The doughs were compared with a standard dough containing no fat. The powders contained 70% vegetable fat or milk fat. The encapsulating agent used was either sodium caseinate or whey protein concentrate (5–10%). Sucrose or lactose were also present in the powders (20–25%). The powders were manufactured at low- or high-pressure homogenization. Farinograph and extensigraph tests were performed on all doughs. Dynamic oscillation tests were conducted in the linear visco-elastic region of the dough. Addition of fat and microencapsulated high-fat powders produced u...

The chondrogenic potential of carbon fiber and carbon fiber periosteum implants: an ultrastructural study in the rabbit

The articular tissue generated on carbon fiber rods in rabbit knee joints after 75 days of intermittent active motion was compared with tissue generated on carbon fiber rods whose articular surfaces were covered with a free reversed periosteal graft. Both methods were effective in generating articular tissue; however, tissue with ultrastructural characteristics similar to those of hyaline cartilage was noted more frequently on the composite implants. If such composite implants were clinically effective then they might be useful in treating symptomatic osteochondral defects.