Simulation of simultaneous water and salt diffusion in dry fermented sausages by the Stefan–Maxwell equation

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.

Modelling desorption isotherm for durable meat products

The desorption isotherms of two durable meat products (sample 1 - durable fermented meat product and sample 2 - unheated durable meat product) by Dynamic Dewpoint Isotherm (DDI) at 20, 25, and 30 °C and Saturated Salt Slurry (SSS) method at 20 °C has been studied. The data acquired from these measurements for 7 models (GAB, DLP, Henderson, Chin, Smith, Oswin, Halsey) were used and statistically evaluated. Based on our collected data, the most suitable model for these types of durable meat products is the DLP model. For the DDI method, DLP model (20–30 °C) reached the R² = 0.999, P value 3.48–4.22 of sample 1 and R² = 0.999, P value 1.51–3.24 of sample 2. For SSS method DLP model (20 °C) reached R² = 0.999, P value 4.23 of sample 1 and R² = 0.998, P value 3.68 of sample 2. The most commonly used GAB model according to statistical treatment was very accurate only for the DDI method, GAB model (20–30 °C) reached R² ≥ 0.994, P value 1.93–7.12 of sample 1 and R² = 0.999, P value 1.76–5.54 of sample 2. In general, for DDI method for both samples have models (DLP, GAB, Halsey, Henderson, and Oswin) a P value of less than 10% for all three measured temperatures. For the SSS method, only the DLP and Henderson models are below 10% for both samples. It has been verified that the DDI method is a suitable and accurate method for measuring desorption isotherms for durable meat products.

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A new Dynamic Dewpoint Isotherm and Saturated Salt Slurry method were compared.

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Technological solution for a new type of durable meat product was designed.

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A new Dynamic Dewpoint Isotherm was more accurate than Saturated Salt Slurry method.

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The new DLP model best fits for durable meat products than commonly used models.

The Risk of Salt Reduction in Dry-Cured Sausage Assessed by the Influence on Water Activity and the Survival of Salmonella

Water activity (aw) is the main hurdle for microbial control in dry-cured sausages. The aw can be influenced by drying or adding electrolytes or humectants. Dry-cured meat products are partially dried, which, together with added salt, results in safe aw values. Currently, there is a trend to reduce salt in meat products, which can compromise the preservation process. The present work aims to evaluate the influences of added salt levels (1% or 3%) and the use or omission of phosphates and wine on the aw of a dry-cured sausage, and to evaluate the possibility of estimating the aw from the moisture loss and the behavior of Salmonella during dry-cured sausage (chouriço) processing. There was a strong relationship between moisture and aw, regardless of the salt level and the presence of phosphates or wine. Predicting aw from moisture loss is possible using the Boltzmann sigmoid function. The salt level strongly influences Salmonella behavior, mainly through aw reduction. An increase in aw by 0.01 units reduced the odds of achieving a 5-log reduction in Salmonella counts to half. Increasing added salt from 1% to 3% increased the odds of achieving a 5-log Salmonella reduction 7.5-fold. The current trend to reduce salt in foods must be carefully approached if applied to cured meat products, as it has substantial consequences on aw evolution and Salmonella survival.

Application of ultrasound-assisted vacuum impregnation for improving the diffusion of salt in beef cubes

The aim of this study was to investigate the effect of different vacuum impregnation (VI) conditions (Control, VI-250, VI-500, VI-750, US-VI-250, US-VI-500 and US-VI-750) on the salt gain (SG) and water gain (WG) kinetics of beef cubes. The cubes were immersed in brine solution (4 g NaCl/ 100 g solution) and salted at different levels of vacuum (250, 500 and 750 mbar) using VI method with and without ultrasound. The final moisture and salt contents of the cubes were 78.60% and 1.59%, respectively, and the samples were salted the fastest with US-VI-250. Five kinetic models were selected to evaluate the SG and WG kinetics, and Azuara model exhibited the best fit. In addition, the salt (D_s) and moisture (D_w) diffusion coefficients were in the range of 5.94-8.11 × 10^-9 m²/s and 5.17-8.64 × 10^-9 m²/s, respectively. It can be concluded that the ultrasound-assisted VI could shorten the brining time by improving the salt diffusion in beef cubes.

Chemical and optical characterization of white efflorescences on dry fermented sausages under modified atmosphere packaging

BACKGROUND

Dry fermented sausages that are packed under modified atmosphere are often affected by the formation of white crystals on the surface. These so called efflorescences are rejected by consumers and lead to high financial losses for the meat processing industry. In this study, the distribution of efflorescence-causing components was investigated over the sausage profile during 8 weeks of storage under modified atmosphere at 4 °C. In addition, two visual methods (image and sensory analyses) were compared regarding the ability to quantify the efflorescence content.

RESULTS

The initial formation of efflorescences was observed after 2 weeks (7%). After 4 weeks of storage, 23.4% of the sausage surface was covered with efflorescences, and the amount of efflorescences did not change significantly by the end of storage. Furthermore, chemical analyses revealed that magnesium (increased by 98.1%), lactate (increased by 54.2%) and creatine (increased by 51.8%) are enriched on the sausage surface during storage.

CONCLUSION

Sensory and image analyses lead to comparable results (r = 0.992) and therefore both are suitable to quantify the amount of efflorescences. The moisture gradient in the interior of the sausages which is built upon drying is supposed to be the driving force for the movement of efflorescence-causing compounds. © 2017 Society of Chemical Industry.