Parma Ham Research Articles

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.

Red Pigment of Parma Ham and Bacterial Influence on its Formation

ABSTRACTThe red pigment of Parma ham was compared with the myoglobin derivatives present in meat and meat products. Spectral patterns of 75% acetone extracts and electron spin resonance spectra from Parma ham differed from those of the myoglobin derivatives. Staphylococci isolated from Parma ham generated red myoglobin derivative from metmyoglobin. Model fermented sausage prepared by inoculation with the isolates developed a more desirable red color without nitrite or nitrate treatment. The red pigment of Parma ham and the model sausage appeared to be the same myoglobin derivative. The reddening of Parma ham is probably caused by the action of bacteria.

Parma ham: Correlation between myotypological parameters of Biceps femoris muscle and qualitative characteristics of fresh and seasoned product

The morphofunctional characterisation of the Biceps femoris muscle was studied in 128 pigs intended for use as Parma ham, as a means of evaluating the raw material in relation to its transformation into a seasoned product answering to the requirements of its trademark. Organoleptic tests were carried out on both fresh and seasoned product, and the seasoned product was chemically characterised. The following defects in fresh hams—muscle which was pale in colour and of unsatisfactory firmness, insufficent compactness, poor thickness of fat cover layer—were found to be strongly correlated to the increase in white fibres of the IIa type; no links were found, however, between the measurement of myofibre diameters and these defects. Principal component analysis, applied to the complete set of histoenzymatic and organoleptic variables considered, reveals the qualitative characteristics of seasoned ham as having no close correlation with the histoenzymatic parameters of the fresh product; the authors nevertheless hope that myotypological examination will become one of the parameters in the evaluation of meat quality.

Changes in volatile compounds of Parma ham during maturation

Changes in the aromatic profile of Parma ham caused by the normal course of aging up to 12 months were examined in order to identify distinctive signals for different maturing periods (6, 9, 12 months). The 28 samples analysed, divided among the three periods mentioned above, provided an aromatic profile in which methyl esters were the most relevant signals, followed by carbonyl compounds and alcohols. The greatest discriminating power is to be ascribed to components such as 3-methylbutanal and ethyl esters, and alcohols like 1-propanol, 1-butoxy-2-propanol and 2-butanol. These compounds were present in higher percentages at 12 months of aging.

Taste quality of Italian raw ham in a free-choice profile study

Six dry-cured hams were assessed by 10 untrained subjects in three free-choice profile sessions aimed at selecting a scorecard and a panel for successive conventional descriptive analysis of Parma ham. Generalized Procrustes Analysis (GPA) of data showed that hams were described by six consistent panellists in terms of six major taste descriptors. The correlations of the selected attributes with compositional data of the same samples were explored by Partial-Least-Squares regression, resulting in four significant relationships. Generally, the regression models of the most meaningful descriptors (after GPA) accounted for most variation and were less affected by inconsistent scoring.

Survival of Viruses in “Prosciutto di Parma” (Parma Ham)

Co-operative studies were undertaken at the Plum Island Animal Disease Center, Agricultural Research Service, United States Department of Agriculture; at the Istituto Zooprofiiattico Sperimentale, Brescia, Italy and at the Istituto Zooprofiiattico Sperimentale, Sassari, Italy to determine if the causative agents for such diseases as foot-and-mouth, African swine fever and hog cholera were inactivated by the processing and curing procedures used in preparing Parma hams. Hams were prepared from pigs infected with each of these diseases when the carcass contained the greatest amount of virus. Foot-and-mouth disease virus could not be recovered from the hams at 108 days in the U.S. experiment and 170 days in the Italian experiment. African swine fever virus was not recovered at 399 days in the U.S. experiment and 300 days in the Italian experiment. The virus of hog cholera was not recovered at 313 days in the U.S. experiment and 189 days in the Italian experiment.

Survival of Swine Vesicular Disease Virus in “Prosciutto di Parma” (Parma Ham)

Experiments were conducted at the Plum Island Animal Disease Center of the Agricultural Research Service, United States Department of Agriculture and at the Istituto Zooprofilattico, Brescia, Italy, to determine if the processing and curing of the Parma hams would inactivate swine vesicular disease virus. The experimental data indicated that the virus was inactivated between 180 and 300d postslaughter in the U.S. experiment and between 90 and 182d post-slaughter in the Italian experiment. The minimal curing period for Parma hams is 365d, which would assure that the ham is free of infectious swine vesicular disease virus.

Observations on the microbiological flora of canned Parma ham.

A significant proportion of a consignment of branded Parma Ham was found to have ;blown' tins; the associated bacterial flora was therefore investigated. No Salmonella or Shigella were found. Clostridium welchii type A and Clostridium bifermentans were isolated in moderate numbers only from enrichment cultures of the ham. Staphylococcus spp. and coryneform bacteria were obtained from all tins and Group D streptococci were present in a few. No food-poisoning cases were associated with this ham.