Food Technology and Biotechnology (Jan 2013)
Texture and Quality Parameters of Slovenian Dry-Cured Ham Kraški pršut According to Mass and Salt Levels
Abstract
The aim of the present study is to investigate the effects of fresh ham mass and the amount of salt added during processing on the technological, sensorial and physicochemical qualities of Slovenian dry-cured ham (Kraški pršut) produced under Protected Geographical Indication. A total of 84 fresh ham samples (pH=5.6–5.9 measured 24 h post mortem) originating from pigs (Landrace × Large white) were divided into subgroups according to mass (light, 9.5–10.5 kg vs. heavy, 11.5–13.0 kg) and salt addition during production (normal vs. low salt). These formed four subgroups for the analyses: light and normally salted, light and low salt, heavy and normally salted, and heavy and low salt. After the salting period, the NaCl concentration in the normally salted muscles was 3.8 to 4.0 %, and in the less salted muscles 2.8 to 3.0 %. During the processing of the dry-cured ham (at the beginning, after salting, and after resting), the semimembranosus (SM) and biceps femoris (BF) muscles were analysed for water activity (aw), pH, salt content, moisture, total minerals, non-protein nitrogen, and total nitrogen. One year after the processing, the instrumental (stress relaxation and texture profile) and sensory qualities were also analysed. After the salting and resting periods, the pH of the samples was significantly decreased in comparison with the fresh ham, although after ageing period this increased again, to reach nearly the initial values (pH=5.59–5.74). At the same time, the aw of both muscles in all experimental groups dropped below 0.90. The total mass losses varied between the groups (34.75–36.63 %), with the samples of heavy and low salt ham showing the greatest mass loss. The light and low salt SM muscles showed slightly higher proteolysis indices (non-protein nitrogen/total nitrogen ratio) after one year, which indicated a trend towards more rapid proteolysis as compared to the normally salted hams. Generally, the softer texture of the BF muscle compared to the SM muscle was confirmed by stress relaxation test, texture profile analysis, and the related chemical parameters (higher moisture content, aw, and proteolysis index). As for the effect of salt on the texture parameters, the SM muscle from the light and low salt ham samples showed greater softness (stress relaxation test), and lower hardness, cohesiveness, gumminess, chewiness and resilience (texture profile analysis) than those from the normally salted hams; the BF muscle showed similar trends to those of the SM muscle. In contrast, the heavy ham samples showed higher values of almost all of the instrumental texture parameters in the low salt hams as compared to the normally salted hams. Significant differences in the majority of the ham sensory traits were mainly due to the differences between the SM and BF muscles.
