Salt uptake and water loss in hams with different water contents at the lean surface and at different salting temperatures

Reduction of salt content variability of dry-cured ham production using non-invasive technologies in an industrial environment

Salt content variability of dry-cured ham production is a challenge for the industry since many factors can influence salt uptake during the salting procedure. The aim of this work was to define and evaluate different modifications of the salting procedure to reduce the salt content variability of an industrial dry-cured ham production. Results showed that magnetic induction (MI) is a valid technology for industrial purposes as it can predict in-line the fat and salt contents of hams with a percentage error of 1.75% and 0.38%, respectively. Modifications of the salting process defined according to raw material characteristics obtained in-line reduced the salt content variability (SD) of the global production from 0.337% to 0.283%. Moreover, a 25% reduction of the salt content variability in hams of similar weight and fat content could be achieved when using a reclassification of the defined categories with MI technology after 6 days of salting. Because of the complexity of the salting process, new tools combined with strategies need to be investigated and developed to overcome the variability coming from other sources than weight and the fat content of hams.

Modelling of salt uptake for salt content standardization in dry-cured ham

Salt content standardization in dry-cured ham production is complex as there are many factors that influence salt uptake. The aim of this work was to study and model salt uptake as a function of salting time and the characteristics of green ham in two different ham types using a large amount of data obtained from an inline non-invasive characterization technology. The usefulness of these models to standardize the salt content of the industrial production was also evaluated. Magnetic induction technology was used to characterize lean and fatty hams in order to further model the salt uptake using different statistical methods. Salt content increased with the salting time showing an asymptotic behaviour which was lower in fatty hams. The best models were those that considered the salting time, weight, and fat content of hams as model independent variables. These models are helpful for salt content standardization within the industry and can be used to simulate process modifications and avoid the time-consuming and costly trial and error tests.

Monitoring physicochemical modifications in beef steaks during dry salting using contact and non-contact ultrasonic techniques

In conventional ultrasonic techniques, the necessary contact between the sensor and the product has constrained the implementation of ultrasound for quality control purposes in the meat industry. The use of novel air-coupled ultrasonic technologies provides multiple advantages linked to contactless inspection. Therefore, this study aims to compare the feasibility of contact (C; 1 MHz) and non-contact (NC; 0.3 MHz) ultrasonic techniques for monitoring the physicochemical modifications undergone by beef steaks during dry salting after different times (0, 1, 4, 8 and 24 hours). Experimental results showed that the ultrasonic velocity increased during salting, which was linked to the reduction in Time-of-Flight ratio (RTOF) and sample shrinkage (velocity C: R2 = 0.99; velocity NC: R2 = 0.93 and RTOF C: R2 = 0.98; RTOF NC: R2 = 0.95). In terms of the compositional changes provoked by salting, the velocity variation (△V) increased linearly (C: R2 = 0.97; NC: R2 = 0.95) with the salt content. As for textural parameters, hardness (C: R2 = 0.99; NC: R2 = 0.97) and relaxation capacity (C: R2 = 0.96; NC: R2 = 0.94) were well correlated with the △V through power equations. Experimental results reflected that the performance of the non-contact ultrasonic technique was similar to that of the contact technique as regards the monitoring of the physicochemical changes undergone by beef steaks during dry salting.

Changes in moisture, colour, residual nitrites and N-nitrosamine accumulation of bacon induced by nitrite levels and dry-frying temperatures

The effects of different nitrite levels (50, 100, and 150 mg/kg meat) and dry-frying temperatures (100, 150, 200 and 250 °C) on the moisture movement, colour, sensory variables and residual nitrite and N-nitrosamine levels in smoked bacon were investigated. Increasing the dry-frying temperatures significantly increased the cooking loss and decreased the moisture content (P < 0.05). The bacon L*-values showed an increasing trend at first and then decreased, with the highest value of the bacon with 150 mg/kg nitrite was obtained at 100 °C and 150 °C. In addition, a*-values were significantly affected by the nitrite level and dry-frying temperature (P < 0.05), with the highest value of the bacon samples with 100 and 150 mg/kg nitrite observed at 250 °C. The residual nitrite content level initially increased (from unheated control to 150 °C) and then decreased (from 150 to 250 °C) sharply with increasing dry-frying temperatures in the bacon samples with the same sodium nitrite levels. N-methyl-N-nitrosoaniline (NMPhA) and N-nitrosomorpholine (NMOR) were measured in a number of smoked bacon samples, and a significant positive correlation (R² = 0.772) was found for N-nitrosamines (NA) contents and nitrite levels (P < 0.05). The maximum levels of NMPhA and NMOR were detected when the bacon with 150 mg/kg sodium nitrite was pan-fried at 200 °C and 150 °C, respectively.

The effects of different processing conditions on biogenic amine formation and some qualitative properties in pastırma

Pastırma, a Turkish dry-cured meat product, was cured at two different temperatures (4 or 10 °C) with two different curing agents (150 mg/kg NaNO₂ or 300 mg/kg KNO₃). The aim of this research was to determine the effects of these factors on biogenic amine content and other qualitative properties (pH, a_w, color, residual nitrite, TBARS, NPN-M, microbiological properties). Residual nitrite was below 10 mg/kg in all samples. Both the curing agent and temperature were found to have a very significant effect on the TBARS value, and the curing agent had a significant effect on the NPN-M content. Curing at 10 °C increased the L* value; the use of nitrate increased the a* value. The use of nitrite had a negative effect on the growth of lactic acid bacteria. Micrococcus/Staphylococcus showed good growth in the presence of nitrate. In all samples, Enterobacteriaceae counts were below detectable levels. Neither temperature nor curing agent had significant effects on the amounts of tryptamine, cadaverine, histamine, tyramine, or spermine. There were very significant effects of temperature on the amount of putrescine and of the curing agent on the amount of spermidine.

Survival of Streptococcus suis, Streptococcus dysgalactiae and Trueperella pyogenes in dry-cured Iberian pork shoulders and loins

Dry-cured hams, shoulders and loins of Iberian pigs are highly appreciated in national and international markets. Salting, additive addition and dehydration are the main strategies to produce these ready-to-eat products. Although the dry curing process is known to reduce the load of well-known food borne pathogens, studies evaluating the viability of other microorganisms in contaminated pork have not been performed. In this work, the efficacy of the dry curing process to eliminate three swine pathogens associated with pork carcass condemnation, Streptococcus suis, Streptococcus dysgalactiae and Trueperella pyogenes, was evaluated. Results of this study highlight that the dry curing process is a suitable method to obtain safe ready-to-eat products free of these microorganisms. Although salting of dry-cured shoulders had a moderate bactericidal effect, results of this study suggest that drying and ripening were the most important stages to obtain dry-cured products free of these microorganisms.

Dry-cured ham tissue characterization by fast field cycling NMR relaxometry and quantitative magnetization transfer

Fast field cycling (FFC) and quantitative magnetization transfer (qMT) NMR methods are two powerful tools in NMR analysis of biological tissues. The qMT method is well established in biomedical NMR applications, while the FFC method is often used in investigations of molecular dynamics on which longitudinal NMR relaxation times of the investigated material critically depend. Despite their proven analytical potential, these two methods were rarely used in NMR studies of food, especially when combined together. In our study, we demonstrate the feasibility of a combined FFC/qMT-NMR approach for the fast and nondestructive characterization of dry-curing ham tissues differing by protein content. The characterization is based on quantifying the pure quadrupolar peak area (area under the quadrupolar contribution of dispersion curve obtained by FFC-NMR) and the restricted magnetization pool size (obtained by qMT-NMR). Both quantities correlate well with concentration of partially immobilized, nitrogen-containing and proton magnetization exchanging muscle proteins. Therefore, these two quantities could serve as potential markers for dry-curing process monitoring. Copyright © 2016 John Wiley & Sons, Ltd.