Post-salting studies in Spanish cured ham manufacturing. Time reduction by using brine thawing-salting

The use of the simultaneous brine thawing/salting on frozen raw material was compared in a previous work with the traditional pile salting method. The aim of this study was to characterise and compare the post-salting stage in Spanish cured ham production by processing fresh and thawed raw material with the traditional pile salting method (which can be considered as the reference method), with the results obtained using the brine thawing/salting method, with and without applying vacuum impregnation. The obtained results show that the thawed salted hams exhibited a higher NaCl diffusion than the fresh ones, implying a shorter post-salting period. Post-salting stage could be reduced from the 50 days employed in the traditional fresh raw material salting, to 25 days when using frozen hams brine thawed/salted. No influence of the use of vacuum impregnation during the salting stage was observed on the post-salting period.     

Effect of brine thawing/salting on endogenous enzyme activity and sensory quality of Iberian dry-cured ham

Simultaneous brine thawing/salting process was applied as an alternative to traditional pile salting process using 51 frozen Iberian hams. The effect of this type of salting process on endogenous enzyme activity and sensory quality of Iberian dry-cured hams was analysed. The frozen hams were simultaneously thawed and salted with saturated brine, with and without vacuum pulses, and were compared to hams thawed under refrigeration and traditionally salted. The peptidase and lipase activities were measured at the end of salting and post-salting stages. The activity of cathepsin B+L was reduced in the two brine salted batches while few differences among batches were observed for the other peptidases. Several lipase activities were significantly reduced in the two brine salted batches. The brine thawed processing affected the free fatty acid content at the different stages although the differences were more appreciated at the beginning of the process and no differences were observed at the end. The long ripening time makes these differences negligible and the consumer did not appreciate any differences between the sensory quality of Iberian brine/thawed hams and traditional Iberian thawed pile salted hams.     

Effect of brine thawing/salting for time reduction in Spanish dry-cured ham manufacturing on proteolysis and lipolysis during salting and post-salting periods

The simultaneous brine thawing/salting operation has been proposed as an effective alternative for the accelerated processing of frozen cured hams. The aim of the present study was to study the effect of this new technology on the lipolytic and proteolytic enzymes responsible for the generation of flavour precursors during the salting and post-salting stages of the manufacturing of Spanish dry-cured ham. The effect of the frozen and thawed process produced a higher proteolytic and lipolytic activity than in the fresh traditional salted hams (FPS) that was detected by a higher concentration in free amino acids and free fatty acids. On the other hand, the brine thawed/salted treatments, at atmospheric pressure (BTS) and with vacuum impregnation (BTS-TP), produced an acceleration of the myofibrillar degradation that occurred in the BTS and BTS-TP hams in comparison to FPS. However, the lipolysis was affected by the frozen treatment but not by the brine thawed treatments, as few differences in free fatty acids and lipase activity were detected among the frozen and brine thawed hams at the end of post-salting stage.     

Accelerated processing of dry-cured ham. Part I. Viability of the use of brine thawing/salting operation

In a previous study, the brine thawing/salting operation using frozen hams as raw material was proposed in order to obtain accelerated processing of dry-cured hams. The time needed to reach the same NaCl concentration on a dry weight basis and the same NaCl concentration in the ham liquid phase for the deeper areas at the end of the post-salting stage were determined.

The aim of this work was to study the influence of the brine thawing/salting operation on the whole dry-cured ham manufacturing process, using the traditional thawing and salting methods as control.

The obtained results indicate that although a strong reduction in the thawing, salting and post-salting stages is obtained by using brine thawing/salting, the time needed in the dry-curing and maturing phases increases compared to those traditionally processed, probably due to the absence of pile salting and thus the reduction in the thickness of the ham piece as a consequence of the ham pressing. From the composition and microbiological point of view, no significant differences were observed among the hams processed by the different treatments.     

Study of salting and post-salting stages of fresh and thawed Iberian hams

Fresh raw material has been traditionally used to obtain dry-cured Iberian ham, although the use of thawed raw material is increasing. This type of raw material has been previously studied for dry-cured production employing White pigs, where the salting time has been reduced to reach similar NaCl concentrations. The aim of this work was the analysis of salting and post-salting stages of Iberian hams, employing fresh or thawed raw materials. The results showed that fresh Iberian hams had higher salt concentrations than thawed Iberian hams for the salting time ratio used, a ratio established to reduce the freezing/thawing effect that was previously observed working with White ham. This fact shows that the Iberian raw material in dry-cured ham manufacturing is less affected, by the freezing/thawing process than the White raw material.     

Accelerated processing of dry-cured ham. Part 2. Influence of brine thawing/salting operation on proteolysis and sensory acceptability

In a previous study, the brine thawing/salting operation using frozen hams as raw material was studied as a valid alternative for the accelerated processing of dry-cured hams. But no information was available on how this treatment could affect some important biochemical mechanisms and the sensory quality of hams. The aim of this work was to study the influence of the simultaneous brine thawing/salting operation on proteolysis and sensory acceptability of the produced dry-cured hams. The results confirm that dry-cured hams can be produced by using brine thawing/salting with a substantial reduction in the thawing and salting time needed. This accelerated process resulted in similar or even better sensory preferences than hams produced through the traditional method. However, the preference of consumers based on the appearance was lower for most of the hams than when using the traditional method, probably due to a wider slice section of the brined hams that can be corrected by adequate pressure during the salting. Thus, this treatment can be used without affecting the quality of dry-cured hams.     

Effect of prefreezing hams on endogenous enzyme activity during the processing of Iberian dry-cured hams

The use of frozen/thawed raw material in the processing of Iberian dry-cured ham has been studied to determine its effect on the sensory quality of the final product. The proteolysis and lipolysis processes were measured by the proteolytic and lipolytic enzyme activities and free amino acids and free fatty acids. The thawed Iberian hams had lower salt contents throughout the process. The use of thawing raw material did not affect the proteolytic enzymes, cathepsins, aminopeptidases and dipeptidylpeptidases, only the activity of dipeptidylpeptidase III was reduced due to thawing. Moreover, there were no differences in the content of free amino acids between fresh and thawed hams during the whole process. However, the use of thawing hams affected the lipolytic activity. The activity of phospholipase and neutral lipase were significantly higher in the thawed hams and also the content of free fatty acids, at all the stages analyzed. Consumer sensory analysis showed thawed Iberian hams had the lowest hardness, probably due to an intense proteolysis. The acceptability of the Iberian hams was similar between fresh and thawed hams.     

Replacement of pile salting by simultaneous brine thawing-salting in Spanish cured ham manufacturing

Salting, is one of the fundamental operations in Spanish cured ham manufacturing, and is basic in order to preserve the product throughout its processing and storage. Pile salting is the method traditionally employed to accomplish this step. The use of frozen raw material has become quite frequent in the industry, and it implies a preliminary thawing step in a cold chamber. The aim of this study is the analysis of the first step in ham production (salting) and the influence of simultaneous brine thawing/salting and vacuum impregnation in the salting stage of Spanish cured ham. The results indicated a reduction in the salting time when using the brine thawing/salting method, which was performed together with vacuum impregnation. Further studies need to be done in order to fully understand the influence of these new salting methods on the following manufacturing steps and the final quality characteristics.     

Influence of pre-cure freezing of Iberian hams on lipolytic changes and lipid oxidation

The purpose of this work was to study the influence of pre-cure freezing of Iberian hams on lipolysis and lipid oxidation during the ripening of the product. At the green stage, the levels of fatty acids (FA) in the free fatty acids fraction were higher in pre-cure frozen (F) than in refrigerated (R) hams, whereas in the polar lipid fraction, FA and dimethyl acetals (DMA) values were higher in R than in F Iberian hams. These results point out the existence of lipolysis phenomena during the freezing storage. At the end of post-salting and at the final stage, both R and F hams showed similar FA and DMA profiles. The effect of pre-cure freezing of hams influenced lipolysis evolution throughout the processing. The development of lipid oxidation was similar in R and F hams, but Thiobarbituric acid-reactive substances (TBAR) values were significantly higher in F hams at the initial stage and at the end of post-salting and drying steps. Despite all these differences, at final stage the FA and DMA composition as well as TBAR levels were quite similar in R and F hams.     

腊肉真空腌制工艺条件的优化

以猪脊背肉为原料,研究了真空腌制工艺中真空压力、腌制液浓度、原料质量和真空腌制时间4个因素对其真空腌制速率的影响。单因素实验及正交实验结果表明,腊肉真空腌制的最佳条件为:真空压力86kPa、腌制液浓度25%、原料质量125g、真空腌制时间5h,方差分析结果显示该最佳工艺与其他各组工艺存在着极显著差异。     

Quantification and kinetics of the residual brine generation during ham and shoulder pile salting

Salting is one of the most important stages of the traditional process of cured ham manufacturing. During pile salting a saturated brine is formed and drips through the orifices located at the bottom of the salting containers.

The objective of the present work was to quantify the released brine in the ham manufacturing industry in Spain and to relate the brine generation with the salt gained by hams in the process.

The total released brine during ham and shoulder salting in Spain was determined theoretically and from the experimental values obtained from the industry (around 38,000 metric tons in 2002). In addition to that, an easy method for the estimation of the NaCl gained by hams and shoulders was developed by using the measurements of the released brine (the estimated NaCl gained differed 3.5% from the experimental data).     

The effect of using PSE meat in the manufacture of dry-cured ham

 Drying, salting, protein changes, colour and the sensory quality were studied in dry-cured ham manufactured from refrigerated and frozen/thawed raw pale, soft and exudative (PSE) meat. The results obtained showed that the use of PSE meat increases the level of drying, salting and proteolysis of the dry-cured ham, although it does not significantly affect the sensory quality. Freezing and thawing of the raw material accentuates the proteolytic and exudative nature of the meat during the curing process, and as a result the salting and drying levels increase to such an extent that the PSE effect in these hams is practically undetectable. Received: 6 June 1997 / Revised version: 17 July 1997     

Recent advances in cured raw ham manufacture

Cured raw hams are a valuable and popular group of meat products. The consumption and international trade have increased during the last years, therefore new technologies to accelerate the production process and to increase product quality and safety are needed. In the current review, an overview of European protected cured raw hams is presented. Furthermore, traditional methods for cured raw ham production together with recent advantages in the techniques for pretreatment (trimming, blade tenderization, and freeze-thawing), curing/salting (tumbling, vacuum impregnation, pulsed pressure, ultrasound, pulsed electric fields, simultaneous thawing/salting), drying/ripening (Quick-Dry-Slice-process, oil drop application, high temperature short time process) and postprocessing (vacuum and modified atmosphere packaging, high hydrostatic pressure, high pressure carbon dioxide, high pressure carbon dioxide with ultrasound) are described. Moreover, application techniques and effects of protective cultures and starter cultures, such as molds, yeasts, coagulase-negative staphylococci and lactic acid bacteria, on cured raw ham quality and safety are reviewed.     

Pre-cure freezing affects proteolysis in dry-cured hams

Several parameters (sodium chloride, moisture, intramuscular fat, total nitrogen, non-protein nitrogen, white precipitates, free tyrosine, L* a* b* values and acceptability) related with proteolysis during the curing were compared in dry-cured hams manufactured from refrigerated and frozen/thawed raw material. Pre-cure freezing increased the proteolysis levels significantly (p<0.05) in the zones of the ham where water losses and absorption of salt is slowest. Frozen hams present a high incidence of white precipitates, formed mainly by tyrosine crystals. The colour and acceptability scores are similar in frozen and refrigerated hams. The previous freezing and thawing process accentuates the water losses, salt absorption and proteolysis of the cured meat, although it does not significantly affect the sensory quality of the dry-cured ham.     

Effects of Added Salt, Phosphates, and Proteins on the Chemical and Physicochemical Characteristics of Frozen Cod (Gadus morhua) Fillets

ABSTRACT: Cod fillets were injected with brine, then immersed in brine with the same composition as used for injection, and finally frozen in a plate freezer. The composition of the brine varied with groups, containing phosphates (3%), salt (5%), and/or proteins (10%), soy protein concentrate, or hydrolyzed cod proteins. The fillets were stored at -24 °C for 3 mo and then thawed to evaluate the effects on yield after thawing and cooking, drip, water-holding capacity, pH, and chemical composition. Addition of proteins slightly increased the yield of thawed fillets, but salt and phosphates were more effective. Comparison of the different proteins showed that fish proteins were not as effective as soy proteins with respect to the physicochemical parameters evaluated with the exception of water-holding capacity. The use of both type of proteins resulted in a negative appearance of the fillets, such as discoloration and slimy surface.     

羊肉脉动真空腌制工艺参数优化及腌制模型建立

为提高腌制速率,以羊肉为材料,研究了脉动真空腌制时间、盐溶液质量分数、真空压力、脉动比（真空压力保持时间与常压保持时间之比）对腌制效果的影响,建立羊肉脉动真空腌制盐分迁移模型。结果表明脉动真空腌制较常压腌制效率提高8%～26%,依据模型预测结果与实际操作所确定的最佳工艺参数为盐溶液质量分数17%、腌制时间6 h、脉动比1.13（17 min∶15 min）,此条件下羊肉盐含量为4.31%,与预测值4.29%非常接近。     

The effects of various salt concentrations during brine curing of cod (Gadus morhua)

The method used for salting of cod (Gadus morhua) is believed to influence the quality and characteristics of the final product. In recent years an initial brine salting for 1–4 days has preceded dry salting; this increases both the weight yield and quality of the final product. After removal from the brine, dry salting is followed by packaging and storage. The effect of the salt concentration in the brine has been a matter of controversy, with some indication that higher weight yield and quality may be obtained by using lower salt concentrations than by using a fully saturated brine solution. Therefore to test this hypothesis, the effect of different brine salting methods was studied; traditional brine salting, maintaining a constant brine concentration and increasing the salt concentration gradually during brining. The results indicated that the effect on weight yield, chemical composition and water holding capacity of the salted or rehydrated cod were not significant. Altering salt concentration of the brine, by adding salt during brining, did not result in any significant improvements in weight yield, either after the salting process or after the rehydration. The overall quality was increased by using a lower salt concentration of 16° Bau compared with 20 and 24° Bau.     

Influence of pre-cure freezing of Iberian ham on proteolytic changes throughout the ripening process

This work aimed to investigate the effect of pre-cure freezing Iberian hams on proteolysis phenomena throughout the ripening process. Non-protein nitrogen (NPN), peptide nitrogen (PN) and amino acid nitrogen (AN) as well as amino acid and dipeptide evolution followed the same trend in both refrigerated (R) and pre-cure frozen (F) Iberian hams during processing. At the different stages of ripening, there were no differences in the content of NPN and AN while F dry-cured hams had higher levels of PN than R hams at the final step. This seemed to be more related to the salt content (lower in F than in R hams) than to the pre-cure freezing treatment. Most amino acids and dipeptides detected showed higher concentrations in F than in R Iberian hams at the green stage, being rather similar at the intermediate phases. At the final stage, the effects of pre-cure freezing of Iberian hams were not well defined, higher levels of some amino acids and dipeptides were found in R than in F Iberian hams whereas other amino acids were lower in R than in F hams.     

Lipolytic and proteolytic properties of dry-cured boneless hams ripened in modified atmospheres

We studied proteolytic and lipolytic properties of dry-cured boneless ham (porcine quadriceps femoris) made with chilled (10°C, 48 h) or frozen/thawed meat (frozen at -20°C frozen for 90 days and followed by thawing at 10°C for 48 h) were determined. Dry-cured meats were stored in modified atmosphere packages (100% N(2) and a mixture of 75% N(2)+25% CO(2)) at 15°C with the intention of reducing ripening space. Results showed that dry-cured hams made with frozen/thawed raw meat had more salt, volatile fatty acids and free fatty acid content after salting and smoking. Whereas, samples prepared with chilled meats contained more nitrogenous compounds (water-soluble nitrogen, non-protein nitrogen, and free amino acids). Volatile and free fatty acid contents in all samples significantly increased with storage. Acetic acid was the predominant volatile fatty acid. To confirm lipolytic activity in dry-cured ham stored in modified atmospheres, we calculated the lipolytic coefficient. The lipolytic coefficients of all samples were positive values and significantly (P<0.05) increased with storage indicating lipolysis in samples were still active. Furthermore, nitrogenous compounds in dry-cured ham significantly (P<0.05) increased with storage indicating proteolysis in samples were not affected by modified atmosphere storage. Aerobic, anaerobic and lactic acid bacteria counts in dry-cured meats were stable to modified atmospheres storage for 20 weeks at 15°C. Flavor, texture and color score in sensory evaluation for dry-cured ham made with chilled meat were significantly higher than that made with frozen/thawed meat. All samples had high overall acceptance scores in sensory evaluation. Results in this study suggested that dry-cured boneless ham stored in modified atmospheres for 20 weeks at 15°C was another feasibility to ripen the meat without affecting lipolysis, proteolysis, microbiology and sensory quality.     

Study of the influence of pulsed electric field pre-treatment on quality parameters of sea bass during brine salting

Pulsed electric field (PEF), as an emerging technique, has recently gained increased popularity in food processing and preservation. However, applications in the seafood industry are still scarce. In the present study, sea bass samples were subjected to PEF pre-treatment prior to brine salting to verify the possible acceleration of the brining rate, increasing the salt uptake and ensuring the homogeneous salt distribution in the muscle. The applied intensity of the current was set at 10 and 20 A (corresponding to a field strength of 0.3 and 0.6 kV/cm) prior to sea bass salting in brine with 5 and 10% salt concentration, respectively. The results have shown that PEF pretreatment could effectively shorten the brine salting time compared to control samples (from 5 to 2 days), or increase the salt uptake up to 77%, ensuring at the same time its homogenous distribution in the muscle. However, myofibrillar protein solubility was significantly reduced in PEF pretreated samples. At the same time, no significant differences in water holding capacity and water activity between PEF pre-treated and untreated samples were found during the whole salting period. Freezable water was influenced by PEF application, but the effect was significant only at the lowest salt concentration during the first period of the salting process.Industrial relevancePEF-assisted brining appears a promising technology in the fish processing industry due to its efficacy in reducing the salt brining time, increasing the mass transfer and enhancing the diffusion of brine into the muscle to ensure the homogeneous distribution of salt in it. The increased salt uptake of the PEF-treated samples compared to control samples shows future potentiality of using PEF prior to salting in the fish processing industry.