Effect of vitamin E deficiency on rabbit intramuscular collagen.

The effect of a vitamin E-deficient diet on muscular collagen was studied in young rabbits. Intramuscular collagen content was found to increase in vitamin E-deficient rabbits, both in absolute and relative values, while no changes in urinary hydroxyproline excretion were observed. The overall solubility of intramuscular collagen was higher and the collagen soluble in guanidine hydrochloride was richer in alpha-chains. Such findings would suggest that avitaminosis E induces the production of new intramuscular collagen.

Effect of some fat replacers on the release of volatile aroma compounds from low-fat meat products.

The effect of fat content and carbohydrate fat-replacers on the release of volatile odor compounds from beefburger, salami, and frankfurter has been investigated. The reduction in fat content in any of the three meat products studied resulted in a tendency toward an increase in the quantities of volatiles released in the headspace. Tapioca starch and maltodextrin appear to delay the release of certain classes of compounds selectively; for instance, tapioca starch appears to slow the release of some Maillard products while maltodextrin has a similar effect on terpenes. In contrast, oat fiber decreases the release of most of the compounds analyzed. Thus, the addition of carbohydrate fat-replacers to low-fat meat products could assist the flavor qualities of low-fat meat products by slowing down the release of odor compounds.

Oxidation in traditional mediterranean meat products.

Lipid oxidation in dry-fermented sausages and dry-salted-hams, representative items of traditional Mediterranean pork products, is responsible for the production of compounds which can affect their organoleptic qualities and wholesomeness. Lipid-derived compounds make up an important share of the volatiles extracted from matured products, once the contribution of spices is removed, and contribute significantly to the flavour of old style products. The few reports available on oxysterols depict a total cholesterol oxidation rate of about 0.1%, a threshold level for toxic effects to occurin vitro but about 100 times lower of thein vivo toxicity dose. The value could perhaps be reduced with the use of antioxidants. Phospholipids are the main class of fats interested by lipolysis and unsaturated fatty acids are those most interested by oxidation. On that basis, the case of special feeding regimes, such as that of Iberian pigs, and the possible relevance of muscle fibre type on flavour development are discussed.

Lipid and colour stability of Milano-type sausages: effect of packing conditions.

Lipid and colour oxidative changes in Milano-type fermented sausages were studied in relation to packing conditions and extended storage under fluorescent light. Matured sausages were sliced and packed under vacuum or in protective atmosphere (100% N(2)) and exposed in a display cabinet to mimic commercial conditions of light and temperature for 2 months. Lipid oxidation was measured by the determination of thiobarbituric acid reactive substances (TBARS) and cholesterol oxidation products (COP), whereas the oxidation of nitrosylmyoglobin was evaluated by a trained sensory panel. Lipid oxidation and discolouration were positively related in vacuum-packed sausages: TBARS and COP values increased significantly concurrently with increasing brown scores. Protective atmosphere came out to be more efficient than vacuum in controlling fatty acid oxidation and, to a lesser extent, cholesterol and pigment degradation: TBARS values remained constant during the whole storage period whereas cholesterol oxides and brown colour scores gradually increased but remained lower than those of vacuum-packed sausages. Higher residual oxygen in vacuum packing could be responsible for the observed differences in oxidative stability.

Note on the effect of ageing on the neutral salt and acid soluble collagen from the intramuscular connective tissue of various species.

The neutral salt soluble (NSSC) and acid soluble collagens (ASC) from the intramuscular connective tissue of various species were extracted, purified and studied by optical rotatory dispersion, viscosity and polyacrylamide gel electrophoresis. No significant changes in the quantity of such soluble fractions, in the optical rotatory dispersion or in viscosity of the purified samples were observed during two weeks storage at 1 °C. Electrophoretical analysis suggested a decrease in the relative concentration of the α chains of the ASC. It was concluded that if there are changes in the NSSC or ASC of muscle during ageing these are not detected by the techniques employed.

Molecular weight distribution of soluble polypeptides from the 'Parma county ham' before, during and after maturation.

SDS polyacrylamide gel electrophoresis has been employed to study the molecular weight distribution of soluble polypeptides from the 'Parma county ham', a salted pork product. Limited proteolysis was observed, but this was mainly confined to the sarcoplasmic proteins. The results are discussed in the light of previous studies on the same type of products.

Oxidative stability of lipids and cholesterol in salame Milano, coppa and Parma ham: dietary supplementation with vitamin E and oleic acid.

An investigation has been carried out on the effect of dietary supplementation with vitamin E and oleic acid on oxidative stability of Italian representative pork products. Fatty acid composition of deposited fat was modified in the oil supplemented groups with negative effects on fat firmness. Oil supplementation significantly increased vitamin E content of muscles, as well. Oxidative stability of fat, evaluated by TBARS and cholesterol oxides, has not shown significant differences between dietary treatments but, although the differences were not significant, the tendency was sufficiently clear, especially in salame Milano, towards a lower oxidation level in vitamin E enriched meat. Cholesterol oxidation was found to vary in general around 0.1% of total cholesterol and the only cholesterol oxides observed were 7ß-hydroxycholesterol, 5,6α-epoxycholesterol and 7-ketocholesterol. Aldehydes content and distribution appeared to be linked, firstly, to the specific processing technology of the product and, secondly, to the changed fatty acid composition.

Objective measurements of pork quality: Evaluation of various techniques.

Research has been undertaken in which various methods for meat quality evaluation were compared. The measures used were pH (by homogenization and by combined electrode), light scattering conductivity, dielectric loss factor and colour. A very low incidence of PSE (Pale, Soft, Exudative) and DFD (Dark, Firm, Dry) cases was observed and the correlation between pH, as measured by homogenization and by combined electrode, did not appear to be completely satisfactory. Dielectric loss factor, as measured by the MS tester, seems to be specifically suited for PSE diagnosis. On the other hand, higher values of light scattering and conductivity measured at 24 h post mortem, are found to be linked to the rate of pH fall, even outside the range for PSE. Colour measurements, especially of the parameters L(∗), a(∗) and hue angle, have given interesting information. In fact, meat could be classified by colour intensity (a(∗), psychometric chroma), by type of colour (hue angle) and by exudative phenomena (L(∗)). No marked effects of rearing techniques have been observed, whereas the genetic background appears to influence some colour parameters. Slaughter conditions, on the other hand, could affect markedly all the meat quality parameters measured in this research.

Objective evaluation of pork quality: Results of on-line measurements.

Research has been conducted on objective pork quality evaluation on line in an industrial slaughterhouse. The investigation, which involved more than 5000 pigs, lasted for 12 working days spread over four consecutive weeks between October and November. Measurements performed were Fat-o-Meat'er carcass classification (lean content, fat and muscle thicknesses), cold carcass weight, 24-h pH of Semimembranosus and Biceps femoris muscles and 24-h colour of Semimembranosus muscle. The results show that cold carcass weight and lean content are only slightly related to meat quality as evaluated by pH and colour. Cluster analysis has confirmed the importance of pH and colour parameters, such as L(∗), a(∗) and hue angle, for the evalaution of pork quality on line in an industrial context.

Volatile compounds of commercial Milano salami.

The relationship between extracted volatiles of Milano salami, one of the main dry-cured sausages produced in Italy, and their olfactory properties was studied. Volatile compounds were extracted by a purge-and-trap method, quantified using a flame ionisation detector and identified by mass spectrometry. Olfactory analysis was performed by sniffing the gas chromatographic effluent. Nearly 80 compounds were identified and quantified: most came from spices (60.5%), 18.9% from lipid oxidation, 11.8% from amino acid catabolism and 4.9% from fermentation processes. Panellists detected 19 odours by sniffing. These odours were associated with spices, lipid oxidation or fermentation and were in agreement with the contributions of each reaction to the overall aroma of the product.

Pig carcass classification in the 65-190 kilogram range using the Danish fat-o-meat'er.

A study was carried out in which 200 pig carcasses were selected in such a way as to cover the most complete range of dead weights and lean contents available on the market in Italy. Left sides were probed for fat thickness and muscle depth at 2 3 , 3 4 and 4 5 LR (last rib) at 7, 9 and 11 cm off the dorsal midline. Fat thickness was also measured at 3 4 and 4 5 LV (last lumbar vertebrate) at 8 and 10 cm off the dorsal midline and, on the dorsal midline, on the middle of the gluteus medius muscle, at the last rib and at the shoulder. Right sides were cut according to the standard 'Parma jointing method' within 1 h post mortem while left sides were cut with a partially modified 'Parma jointing method' after overnight chilling. Each joint of the first 120 left sides was weighed and separated into subcutaneous and intermuscular fat, bone and meat to establish meat content. The results were used to fix a partial dissection formula which was employed for 74 of the remaining sides while 6 were totally dissected to verify the formula.

Lipid composition, retention and oxidation in fresh and completely trimmed beef muscles as affected by common culinary practices.

The objective of this study was to determine how and to what extent several culinary practices (i.e. household cooking methods), each applied to the beef muscle deemed most suitable (boiling to infraspinatus, broiling to longissimus lumborum, oven-roasting and microwaving to semitendinosus), could induce significant changes in: lipid and cholesterol contents, fatty acid composition and contents, their true and apparent retention values, and some indices of lipid oxidation. Most nutrients increased their concentration as a consequence of moisture loss through cooking, whilst no substantial variation was induced in fatty acid composition. Nevertheless, each cooking method had its own distinctive heat processing parameters, which interacted with the characteristics peculiar to the pertaining muscle, leading to markedly different evaporative and drip losses, significantly different true retention values for cholesterol and the sum of polyunsaturated fatty acids, distinct responses as to lipid oxidation liability. The selected culinary practices seemed to be able to interact with the composition of the selected muscles, up to the point that pro-oxidant conditions were in some way counteracted by antioxidant effects.

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.

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.

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.

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.

Comparison of contaminant and residue levels in organic and conventional milk and meat products from northern Italy.

Due to the growing interest in organic products, a comparison between the chemical safety of organic and conventional products was undertaken. Milk and meat were the products chosen for study. The parameters evaluated to assess chemical safety were organochlorine pesticides, polychlorinated biphenyls (PCBs), lead, cadmium and mycotoxin contamination. Pesticides and PCBs residues in both organic and conventional milk and meat were lower than legal limits. Lead and cadmium residues were very low and did not differ between organic and conventional products. However, aflatoxin M1 contamination in some but not all samples of organic milk was significantly higher than those of conventional milk, although factors other than organic production might be implicated.

Biochemical and microbiological events of Parma ham production technology.

Parma ham technology relies on a few basic points. They are: a fresh meat substantially free of microbial deep contamination, a relatively long phase (up to 100 days) at cold temperatures at the beginning of processing, an uncovered muscular surface as reduced as possible, a long period of maturation. The final product, the matured ham, is the result of a slow process of dehydration which, combined with a limited penetration of salt into the muscles, lowers the water activity to values around 0.90. Surface bacterial contamination is mainly made up by Enterobacteriaceae and Pseudomonadaceae. Among them E. agglomerans and S. liquefaciens are able to grow at 2 degrees C and salt concentrations up to 7.5% and can be responsible for taint development. Micrococci penetrate into the meat during salting and can reach values of 10 x 6 but decrease substantially towards the end of maturation. Maturation, from a biochemical point of view, is characterized by hydrolytic phenomena interesting nitrogen compounds and fats. As a result free amino acids, non protein nitrogen, volatile fatty acids and carbonylic molecules are produced. Such products are important for the development of typical organoleptic characters.

Residues of beta-lactam antibiotics in bovine milk: confirmatory analysis by liquid chromatography tandem mass spectrometry after microbial assay screening.

A procedure for the simultaneous determination of the residues of seven beta-lactam antibiotics (penicillin G, ampicillin, oxacillin, amoxicillin, dicloxacillin, cephalexin, cephapirin) in bovine raw milk using tandem liquid chromatography mass spectrometry (LC-MS/MS) is described. The antibiotics were extracted by an acetic acid solution after centrifugation and filtration. The beta-lactams were separated using reversed-phase liquid chromatography. A triple quadrupole mass spectrometer was used in positive-ion mode as a detector via a Turbo Ionspray interface for electrospray ionization (ESI). The limits of detection and quantitation of the method were below the legal tolerances, except for ampicillin. The method was used to confirm 53 samples found positive by a microbial method (Delvotest SP) at the Istituto Zooprofilattico Sperimentale per la Lombardia e l'Emilia Romagna of Brescia during 2001. Penicillin G was found in 26 samples at concentrations ranging from less than 4 to 6240+/-550 microg x l(-1). Amoxicillin was found in three samples at concentrations ranging from 8.5+/-0.1 to 53.7+/-2.3 microg x l(-1). Cephapirin was found in two samples at 5.7+/-0.1 and 6.4+/-0.3 microg x l(-1).