Oxidative stability and dietary treatment with vitamin E, oleic acid and copper of fresh and cooked pork chops.

Research has been conducted on the effects of feed supplementation with vitamin E, oleic acid (sunflower oil) and copper on some quality characteristics of pork chops. The study was based on the measurement of pH 45' and 24 hr post mortem, proximate composition, colour both objective and sensory, colour stability after packing in oxygen permeable film and protective atmosphere, copper and iron contents, vitamin E content in fresh and cooked chops, peroxide and TBARS value in raw and cooked meat, total cholesterol, cholesterol oxides and aldehydes in cooked meat, sensory evaluation of the eating quality of cooked chops and iodine number of subcutaneous fat. Vitamin E content was significantly higher with oil and vitamin supplementation. No variation has been observed in copper and iron contents. A higher stability of the colour of meat packed under modified atmosphere has been observed with increasing vitamin E content, but the same did not apply with meat packed in oxygen permeable film. No differences have been observed on fatty acid oxidative stability of fresh m. longissimus dorsi and cooked chops (peroxide and TBARS values), on cholesterol oxidation and aldehydes production of cooked chops with increasing vitamin E content. Iodine number in supplemented animals reached levels normally considered at risk for fat firmness.

Lipid and cholesterol oxidation in frozen stored pork, salame Milano and mortadella.

An investigation has been carried out on oxidative processes of fresh and stored frozen pork and of two pork products (salame Milano and mortadella). Wholesale pork cuts (shoulder, ham trimmings, belly and backfat) were checked fresh and after frozen storage (1, 3 and 6 months). The streaky bacon was studied fresh and after scalding at 80 °C. Salame Milano and mortadella were produced with fresh and frozen raw materials and a few commercial samples were also part of the study. No real differences have been observed between commercial and experimentally produced salame and mortadella. Peroxide and TBARS values were low in all cases. Among the cholesterol oxides determined (7ß-hydroxycholesterol, 5,6α-epoxycholesterol, 7-ketocholesterol and 25-hydroxycholesterol) those dangerous for human health were either absent or their concentration was below toxic levels. The results are discussed on the light of literature reports and Italian pork products technologies.

Comparative evaluation of some antioxidants in salame Milano and mortadella production.

Six formulations of salame Milano and mortadella were produced, one without antioxidants, two with sodium ascorbate (0.05-0.1 and O.2%), one with catechin, one with phytic acid, and one with sesamol. The products were studied for oxidation levels (peroxide value, TBARS, cholesterol oxides) and colour stability. The evaluation of the latter took place in conditions simulating commercial types of packaging (vacuum and modified atmosphere) and display. A significant difference emerged in colour stability. With the exception of salame Milano packed under modified atmosphere, in all cases salame and mortadella produced without Na ascorbate had significantly lower colour stability. Both in salame and mortadella, peroxide values and TBARS determination gave indications of a possible pro-oxidant effect of ascorbate 0.2% compared with an effective antioxidant activity of the other compounds tested. Cholesterol oxidation in salame appeared to be inhibited by sesamol and ascorbate while catechin was much less effective. In mortadella the prooxidant effect of Na ascorbate was confirmed. All lipid oxidation parameters, though, showed low oxidation values so that no quality nor health deficiencies could be envisaged with any of the formulations adopted. Lower colour stability scores, though, would create commercial problems.

Lean colour of green and matured Parma hams: Comparative evaluation and technological relevance of sensory and objective data.

Research has been conducted on the relationship between sensory evaluation and objective measurement of pork colour. The study also investigated the relationship between the colour of fresh meat and the colour of matured hams. Sensory evaluation was carried out at 24 h post mortem on the freshly cut surfaces of green hams trimmed for Parma ham production. Objective measurements were performed at the same time on Semimembranosus and Biceps femoris muscles with a Minolta Chromameter Reflectance II CR200/08. Cold carcass weight, lean content, trimmed ham weight, 45 min and 24 h post mortem pH of Semimembranosus muscle were also recorded. The hams were processed according to Parma ham technology. Weight losses at standard processing times were collected. At the end of processing a sample of about one-third of the hams was evaluated for internal lean colour and lean firmness both by sensory panel and objective measurements. Proximate composition was also determined. The results showed highly significant relationships between colour sensory scores and the coordinates L (∗), b (∗) and hue of the C.I.E. L (∗)a (∗)b (∗) colour system. Among the other parameters measured on fresh meat only 24 h pH was related at a very significant level with sensory and objective colour values. Correlation coefficients were generally higher for Semimembranosus than Biceps femoris. Matured ham colour was linked with fresh meat sensory judgements, L (∗), hue and a (∗) values. The relationship, though, was not sufficiently strong for use in predicting the colour of matured hams from green ham characteristics. Processing appears to have a positive effect on the colour of pale meat. Weight losses were mainly linked with lean meat content; other quality attributes being less important. Lean firmness of matured hams was related to the colour and pH of the fresh meat.

Organochlorine pesticide residues in meat of various species.

The quantity of organochlorine pesticides present in pork, rabbit, chicken, turkey and horse meat was determined. Levels of residual pesticide were rather higher in the latter three species than in the former two. They were not closely related to fat content.

Mercury, chromium, lead and organochlorine pesticide residues in some food products of animal origin: A review.

The authors present the results of several years' work in the field of food pollution. The research, which has been carried out on food products of animal origin marketed in the north of Italy, has established that the degree of contamination by heavy metals (mercury, chromium and lead) and organochlorine pesticides is generally lower than the tolerances suggested by the World Health Organisation.