PRKAG3 and CAST genetic polymorphisms and quality traits of dry-cured hams-II. Associations in French dry-cured ham Jambon de Bayonne and their dependence on salt reduction

This study aimed to evaluate the effects of PRKAG3 Ile199Val and CAST Arg249Lys and CAST Ser638Arg polymorphisms on the quality traits of the French dry-cured ham Jambon de Bayonne and their interaction with salt reduction. Significant (p<0.05) and suggestive associations (p<0.10) between the polymorphisms and several quality traits of dry-cured ham, mainly related to processing and textural properties, were found. PRKAG3 Ile/Val and CAST 249Lys/638Arg presented the highest scores for sensory and processing properties, whatever the salt content.     

PRKAG3 and CAST genetic polymorphisms and quality traits of dry-cured hams—III. Associations in Slovenian dry-cured ham Kraški pršut and their dependence on processing

The aim of the present study, the third in a series of three papers, is to show the effects of PRKAG3 and CAST gene polymorphisms on the quality traits of the Slovenian dry-cured ham “Kraški pršut” and their interaction with ham producers. Significant interaction of polymorphisms with producer in the case of salt content, lipid oxidation (PRKAG3 Ile199Val), proteolysis index (CAST Arg249Lys) and pastiness (CAST Ser638Arg) indicated that genotype manifestation was reliant on the manufacturing practice. PRKAG3 Ile199Val polymorphism affected several physico-chemical, rheological and sensory traits. The Ile/Ile genotype yielded less salty and softer hams, indicating beneficial effects on dry-cured ham quality. The effect of CAST polymorphisms was less pronounced, although the observed associations with pastiness, proteolysis index and several free amino acid concentrations indicate its possible influence on proteolysis, with haplotype CAST 249Arg/638Ser being associated with a higher degree of proteolysis.     

PRKAG3 and CAST genetic polymorphisms and quality traits of dry-cured hams-III. Associations in Slovenian dry-cured ham Kraški pršut and their dependence on processing

The aim of the present study, the third in a series of three papers, is to show the effects of PRKAG3 and CAST gene polymorphisms on the quality traits of the Slovenian dry-cured ham “Kraški pršut” and their interaction with ham producers. Significant interaction of polymorphisms with producer in the case of salt content, lipid oxidation (PRKAG3 Ile199Val), proteolysis index (CAST Arg249Lys) and pastiness (CAST Ser638Arg) indicated that genotype manifestation was reliant on the manufacturing practice. PRKAG3 Ile199Val polymorphism affected several physico-chemical, rheological and sensory traits. The Ile/Ile genotype yielded less salty and softer hams, indicating beneficial effects on dry-cured ham quality. The effect of CAST polymorphisms was less pronounced, although the observed associations with pastiness, proteolysis index and several free amino acid concentrations indicate its possible influence on proteolysis, with haplotype CAST 249Arg/638Ser being associated with a higher degree of proteolysis.     

PRKAG3 and CAST genetic polymorphisms and quality traits of dry-cured hams - I. Associations in Spanish dry-cured ham Jamón Serrano

The functional single polymorphisms identified in the calpastatin (CAST) gene have been related to the rate of meat tenderization and the protein turnover after slaughter, and the Ile199Val polymorphism identified in the coding region of the protein kinase AMP-activated (PRKAG3) gene has been proven to affect ultimate pH in muscle. The aim of the present study was to show the effects of these genetic polymorphisms on the quality traits of Spanish dry-cured ham Jamón Serrano. A tissue sample from 665 crossbreed pigs were genotyped for PRKAG3 Ile199Val, CAST Arg249Lys and CAST Ser638Arg polymorphisms, and a subsample of 120 dry cured hams was selected to perform physico-chemical, rheological, instrumental colour and sensory analyses. Associations between the polymorphisms and several quality traits of dry-cured ham, mainly related to flavour and texture, were found. The genotypes PRKAG3 Ile/Ile, CAST249 Arg/Arg and CAST638 Arg/Arg, and the haplotype CAST 249Arg-638Arg were the most favourable for Jamón Serrano production.     

Proteomic profile of dry-cured ham relative to PRKAG3 or CAST genotype, level of salt and pastiness

Two-dimensional electrophoresis was used to compare dry-cured biceps femoris insoluble protein fraction according to genotype (PRKAG3Ile199Val and CASTLys249Arg/Ser638Arg) as well as salt and pastiness level. The PRKAG3 affected mainly muscle metabolic enzymes, indicating its possible influence on muscle metabolism with heterozygotes Ile/Val appearing different from both homozygous genotypes. The effect of CAST was smaller, affecting the quantity of one actin fragment. Dry-cured ham salt and pastiness level affected a wide variety of protein spots including metabolic enzymes, plasma proteins, chaperones and myofibrillar proteins, including protein fragments, indicating the connection with proteolysis. Pastiness was associated with salt content, reflected also by the fact that many spots were affected by both factors. Despite the absence of extreme pastiness (or low salt samples), some protein spots (actin, MHC fragment, desmin fragment) exhibited important differences in intensity according to pastiness (and salt level) suggesting they could be used as potential quality markers.     

Relations between compositional traits and sensory qualities of French dry-cured ham

The left hams of 20 pig carcasses were processed by dry-curing for either 179 (n = 10) or 273 days (n = 10). The Biceps femoris was taken at the end of the processing and submitted to chemical and sensory analyses. The following chemical traits were determined: pH, moisture, salt content, fatty acid content and composition of lipid classes (triglycerides, phospholipids, free fatty acids), nitrogen fractions (soluble and insoluble protein, non-protein nitrogen, free amino acids) and volatile compounds. Sensory analysis was performed by a panel of 12 trained members, who scored texture traits (firmness, dryness, fibrousness, mellowness), taste (salty, acid), intensity of aromas (typical of dry ham, fresh meat, fat, cured meat, rancid, metal), persistence of dry ham aroma, persistence of taste after deglutition, persistence of astringency, persistence of metallic taste. The sensory qualities of dry-cured ham showed noticeable changes between days 179 and 273. Firmness, dryness and intensities of aromas typical of dry-cured ham and cured meat were enhanced with time. Neither pH, moisture nor salt content played a noticeable role in determining the sensory quality of dry-cured ham. Among the volatile compounds, the levels of several ketones and 1-butanol were significantly correlated with the aromas of dry ham and cured meat, while rancid aroma was related to aldehydes, ethylacetate, 2,3-pentanedione and nonane. Therefore, the aromas of dry ham and cured meat appeared to be determined mainly by the products of lipid oxidation. However, they were related also to unidentified volatile compounds, whose identification would be of particular interest.     

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.     

Sensory and Texture Quality of Dry-Cured Ham as Affected by Endogenous Cathepsin B Activity and Muscle Composition

Hams were processed with standard cure adjuncts under two drying temperatures and analyzed after aging for 7 mo. Dried hams revealed that flavor and texture traits were affected by moisture and nonprotein nitrogen (NPN) content and that NPN was enhanced by greater cathepsin B activity, lower salt levels and higher temperature. Two major defects of dry-cured ham, mushy mouthfeel and surface white film, occurred in about 15% of samples. Most of these hams had abnormal NPN values and were shown to originate from meat with high enzyme activity and low protein content. We concluded that this type of meat is prone to uncontrolled proteolysis and related undesired traits, and to be a potential hazard in dry-cured hams cured with less salt.     

Use of computed tomography to study raw ham properties and predict salt content and distribution during dry-cured ham production

Varying salt content in hams of equal brand is a major challenge for Norwegian dry-cured ham producers. This study was thus undertaken to test existing computed tomography (CT) calibration models for salt on entire hams, regarding predictability of salt content at different processing times including final ham and to study salt distribution during processing of dry-cured ham. Twenty-six hams were scanned by computed tomography (CT) 11 times during dry-curing for this purpose. However, previously established calibration models had to be adjusted as they overestimated salt in dry samples. Prediction of ultimate salt content was more accurate approaching the end of the dry-curing process (RMSEP = 0.351-0.595% salt). Inclusion of remaining weight loss improved the prediction accuracy in un-dried samples by approximately 0.1% NaCl. The prediction errors were sufficiently low to be of practical interest.     

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.     

Amino acid and nucleotide contents and sensory traits of dry-cured products from pigs with different genotypes

The free amino acid and nucleotide contents of dry-cured ham, shoulder and loin from two genetic lines selected from pigs according to the paternal allele (homozygous AA and heterozygous AG) of the insulin-like growth factor-II gene were studied by HPLC. Their influence on the flavor and taste characteristics was also studied. The increase of lean content caused by the IGF-II mutation could affect proteolysis during the ripening process and therefore the sensory characteristics. The lower intramuscular fat content in the AA ham batch had a positive effect on the free amino acid content. However, similar flavor traits between ham batches were found, but the AG loin batch showed greater value. The enhancing effect of the IMP on the overall flavor intensity was limited by the amino acid and the IMF contents in dry-cured ham and loin, while in dry-cured shoulder, the IMP could be the reason for the significant differences in after taste and cured flavor scores.     

基于SPME-GC-MS、电子鼻、电子舌技术联用对不同替代盐干腌火腿风味成分表征

研究不同食盐配方对干腌发酵火腿理化特性、细菌菌群变化、挥发性风味物质、风味特征的影响.以4种盐配方发酵火腿,分别为对照组(CK:100％氯化钠)、替代组1(K:30％乳酸钾+70％氯化钠)、替代组2(K+L:18％乳酸钾+12％赖氨酸+70％氯化钠)、替代组3(K+J:18％乳酸钾+12％精氨酸+70％氯化钠).结果表...     

Associations of DNA markers with meat quality traits in pigs with emphasis on drip loss

Phenotypic information on 1155 market pigs for several pig meat quality traits, was collected. Genotypes on 12 DNA markers, including RYR1 and PRKAG3 I199V, were also obtained on all pigs to investigate the relationship between genetic markers and meat quality. The RYR1 gene had the highest impact on meat quality, however, several other markers showed significant effects on one or more traits. Animals heterozygous at the RYR1 locus were significantly inferior in almost all meat quality traits, except ultimate pH value, initial conductivity and redness of the meat. Drip loss from case-ready meat (measured from 1 to 7 days post-mortem) was 43% higher for heterozygotes than animals of the stress resistant genotype. The homozygous genotype II at position I199V of the PRKAG3 locus also resulted in less drip loss than genotypes IV and VV, regardless of the method and time of measurement. Furthermore, the favourable genotype related to higher ultimate pH and darker meat. Both loci significantly affected the intercept, linear and quadratic terms of fitted drip loss development curves. The favourable genotypes showed a lower drip loss after one day of measurement and a slower increase and a more linear development over time. Whilst the RYR1 and PRKAG3 markers influenced numerous meat quality traits, some of the other markers were also found to have significant effects on one or two meat quality traits. Markers at MC4R and HMGA1 loci significantly affected drip loss, whereas LDHA, CAST (Hpy188I) and ATP2A1 influenced pH value. In addition, the marker ATP2A1 was associated with variation in intramuscular fat content in M. longissimus dorsi. GLUT4 affected temperature 45min post-mortem and several markers (MC4R, LDHA, GLUT4, HMGA1, CAST (Hpy188I and PvuII)) influenced one or two of the different colour measurements. The markers at MC4R, CKM, AGRP, PRKAG3, and HMGA1 loci were tested for their interactions with RYR1 regarding drip loss. Only AGRP showed a significant interaction, but this was based on only a few animals with the homozygous genotype for one allele. Our results suggest that genetic markers provide a useful tool to improve meat quality in pigs independently from RYR1, especially the mutation I199V in the PRKAG3 gene.     

干腌火腿低盐腌制强化高温发酵成熟工艺优化

以新鲜杂交猪后腿为原料,发酵成熟温度、腌制用盐量、后熟时间、氯化钾替代比例为考察因素,采用正交试验优化火腿现代发酵成熟工艺,并分析加工工艺对其脂质氧化及感官品质的影响。结果表明:火腿在发酵成熟过程中4个工艺因子均对其脂肪氧化和总体感官均有显著影响(P0.01),氯化钾替代比例及腌制用盐量为影响感官的主要因素。通过正交试验优化后火腿的加工工艺为用盐量6.5%、氯化钾替代比例30%,采用12~13℃发酵10 d后于14~18、19~28、29~34℃分别发酵15 d,再于35~37℃后熟45 d。     

Effects of halothane genotype and pre-slaughter treatment on pig meat quality. Part 2. Physico-chemical traits of cured-cooked ham and sensory traits of cured-cooked and dry-cured hams

Forty-eight castrated F₂ offspring of Piétrain and Large White pigs were allocated to a 3×2 factorial design in order to study the interactive effect of halothane genotype (NN, Nn and nn) and pre-slaughter treatment (referred to as ’Experimental’ (EXP) and ’Commercial-like’ (COL) conditions; the latter involving short transportation, mixing unfamiliar pigs and slaughtering shortly after transport) on the qualities of cured-cooked and dry-cured hams. At 24 h post mortem, the hams were collected and assigned to cured-cooked (right ham) and dry-cured (left ham) ham processing. A sample of M. semimembranosus (SM) was collected before cooked ham processing, was used for chemical composition analysis, cured and then cooked at various temperatures. Cooking losses and compression tests were carried out after cooking on these SM samples. The water and collagen content of SM muscle was significantly higher in nn pigs compared with the two other genotypes. At all cooking temperatures (60, 65 and 70 °C), SM muscles from nn pigs showed higher cooking losses and instrumentally assessed toughness than the other genotypes, the heterozygous pigs being intermediate. The technological yield of cured-cooked ham processing was lower in nn, compared with NN and Nn animals. Cooked hams from nn pigs were drier, tougher, stringier and less smooth than NN and Nn pigs. The heterozygous pigs were similar to normal pigs for all texture characteristics with the exception of toughness for which they got a significantly higher score than NN pigs. The pigs slaughtered under the COL conditions had a better slice cohesiveness and a significantly lower dryness, than pigs slaughtered under the EXP conditions. The effect of HAL genotype on slice cohesiveness was significant only when pigs were slaughtered under the EXP conditions. Dry-cured hams from nn pigs showed significantly more visual defects, but were less tough, smoother and more fondant (softer) than NN and Nn pigs. The dry-cured hams from pigs slaughtered under the COL conditions had a better cohesiveness between muscles and a more intense yellow colour of fat than those from pigs slaughtered under the EXP conditions. COL pigs were also judged significantly less tough, smoother and more fondant than EXP ones. Overall, the effects of pre-slaughter treatment were small compared with those of the HAL genotype. The effects of HAL genotype on the sensory traits of cured-cooked ham were similar to those reported for fresh meat. However, the good textural characteristics of dry-cured ham processed from HAL positive pigs are somewhat surprising and need to be confirmed.     

干腌驴肉火腿加工过程中理化特性的动态变化

为了探究驴肉火腿加工过程中的品质变化及风味的形成规律,对加工过程中7个工艺点(原料期、腌制初期、腌制中期、腌制末期、发酵初期、发酵末期、成熟期)驴肉火腿的理化特性和氧化变质规律进行了研究,以期找到驴肉火腿最佳发酵时间。结果表明,在加工过程中,驴肉火腿pH比较稳定且处于微酸性环境中(6.2~6.6),各工艺点差异不显著(p>0.05);水分含量由72%先显著(p<0.05)下降后趋于平稳在35%,NaCl含量显著(p<0.05)上升在成熟期达到12.39%;TBA值先显著(p<0.05)上升至最大值0.385 mg/kg后缓慢下降最后趋于平稳在0.34 mg/kg且火腿未出现腐败现象,POV显著上升(p<0.05)成熟期达到5.26 meq/kg在国家标准范围内;TVB-N含量呈现稳定上升趋势,在成熟期含量达到85.76mg/100g且能表现出浓郁的特有香味;灰分含量先显著上升(p<0.05)后趋于平稳(p<0.05)。综上所述,驴肉火腿加工过程中理化和氧化特性的变化影响了火腿品质和最终风味的形成且发酵6个月时火腿风味最佳。     

云南干腌火腿加工工艺及其品质影响因素研究进展

云南干腌火腿是一种重要的传统发酵肉制品,以猪后腿为原料,经腌制、风干、发酵等加工而成。云南干腌火腿主要有宣威火腿、撒坝火腿、三川火腿、老窝火腿、诺邓火腿及鹤庆火腿等,本文对云南干腌火腿加工工艺及干腌火腿品质影响因素进行综述,从原料肉、腌制条件、色泽及风味等几方面做了详细讨论,旨在为干腌火腿品质改进提供一定的理论参考。     

火腿风味的低钠发酵肉制品品质及风味研究

以猪后腿肉为原料,利用发酵火腿生产工艺参数制成具有火腿风味的产品。采用乳酸钾和L-精氨酸替代30%钠盐用于加工,研究其对发酵肉制品水分活度、颜色、水分含量、蛋白质含量、质构特性、硫代巴比妥酸值等品质指标及产品风味的影响。结果表明:采用不同配比的乳酸钾和L-精氨酸替代30%的钠盐,在保证产品风味的同时,均能降低发酵肉制品中钠含量;结合理化指标及感官评定,采用9%L-精氨酸+21%乳酸钾或12%L-精氨酸+18%乳酸钾的效果最佳。     

THE STUDY OF INGREDIENTS AND PROCESSING TECHNIQUES OF XUANWEI STYLE HAM

Xuanwei style ham is one of the famous dry-cured hams in the world. The influences of different ingredients and processing techniques on sensory properties, brine diffusing rate, chemical composition and hygienic quality of Xuanwei style cured ham were studied. Modified cured ham processing techniques were employed in this study. Massaging of green ham and injection of curing solution improved brine diffusing rate ( P <  0.05) and reduced curing time from the traditional 28 days to 21 days (weight of green ham about 13 kg). Ninety mg/kg sodium nitrite was used for improving cured ham color ( P <  0.05), and its residue still met the Chinese cured ham standard of 20 mg/kg. The hygienic and sensory qualities were not significantly affected by the addition of sodium ascorbate and polyphosphate ( P >  0.05).

PRACTICAL APPLICATIONS

The paper studied the Chinese famous Xuanwei dry-cured ham, modified curing ingredient and processing techniques of Xuanwei ham are beneficial for improving the ham quality and important to shorten the traditional cured ham processing procedure such as longer processing time and seasonal processing method to adapt to the new industrial procedures of manufacturing and marketing of Xuanwei cured ham.     

Lipid oxidative changes throughout the ripening of dry-cured Iberian hams with different salt contents and processing conditions

Hexanal content and TBARs were monitored in Semimembranosus and Biceps femoris muscles throughout the ripening of 46 dry-cured Iberian hams processed with different amounts of salt (6% vs. 3% w/w) and different processing systems (traditional vs. modified). Rancid odour and rancid flavour were sensorially analysed in the final product. Hams processed at higher temperatures during the drying stage, following a traditional system, showed lower values in this phase for hexanal content in both muscles (P<0.001), but TBARs showed the opposite behaviour (P<0.001 and P<0.05 for Semimembranosus and Biceps femoris, respectively). Salt content affected hexanal content of each muscle in a different way. Semimembranosus muscles from traditionally processed hams showed lower rancid flavour scores (P<0.001) while salt did not significantly affect rancid odour or aroma scores (P>0.05). Evidently the effects of salt content and processing temperature, within studied ranges, on lipid oxidation are limited. In fact, increased processing temperature, during the drying stage, does not lead to greater oxidation in dry-cured ham, in spite of the well known pro-oxidant effect of temperature.