Bent Riber Petersen

Impact of salt, phosphate and temperature on the effect of a transglutaminase (F XIIIa) on the texture of restructured meat

The effect of the transglutaminase F XIIIa on texture parameters was analysed in meat model systems simulating a restructured meat product. Porcine M. longissimus dorsi at normal ultimate pH was obtained 2 days post mortem from pigs slaughtered at approx. 100 kg liveweight. The F XIIIa product used was a recombinant protein produced by fermentation of Saccharomyces cereviciae. In raw minced meat F XIIIa increased cohesion, hardness and elasticity when a time-temperature heat treatment of 37 °C and 90 min was used during processing, while processing at 10 °C for 23 h caused only minor texture changes. Salt and phosphate addition together with F XIIIa resulted in a remarkable increase in binding properties. Thus, the texture parameters increased particularly at salt levels between 2 and 4% and a phosphate level of 0.2%. Binding of meat pieces containing 0.2% phosphate, 1% salt and F XIIIa as 0.4% active enzyme to substrate showed significant effect on the tensile strength compared to the samples without F XIIIa, however, color deterioration of the product was observed when adding F XIIIa.

Safety evaluation of a fungal pectinesterase enzyme preparation and its use in food.

The Aspergillus aculeatus pectinesterase enzyme is used to modify the texture of plant derived products. It is produced by A. oryzae transformed with the cloned full length cDNA of A. aculeatus encoding pectinesterase. It was subjected to a series of toxicological tests to document safety in use. The enzyme preparation was not found to be mutagenic in the Ames test, and did not cause chromosomal damage in a human lymphocyte assay. In a 13-week oral-toxicity study in rats, with daily dosages up to 10 g enzyme preparation kg body weight (b.w.), there were no adverse effects on mortality, clinical signs, body weight, food or water consumption, ophthalmoscopic findings, haematology or clinical chemistry. There were also no notable necropsy or histological findings. Statistically significant increases in heart weight were noted in male animals treated with 5 or 10 g enzyme preparation/kg b.w./day, following covariance analysis. However, this was not considered to be related to treatment with the enzyme preparation. The issue of the levels of free liberation of methanol in products processed with pectinesterase is addressed, and it is concluded that, from a nutritional and physiological point of view, free as well as bound methanol must be considered.