Contribution of a selected fungal population to proteolysis on dry-cured ham

The proteolytic changes taking place in dry-cured hams lead to increases in free amino acids. Such free amino acids not only contribute to flavour, but also serve as precursors of volatile compounds. Several months of ripening time are required to allow the particular flavour to develop. The fungal population allowed to grow on the surface of some types of dry-cured could play a key role on proteolysis, as it has been shown for dry-cured sausages. The purpose of this work was to study the possible contribution of fungi to proteolysis in dry-cured ham. For this, a strain each of non-toxigenic Penicillium chrysogenum (Pg222) and Debaryomyces hansenii (Dh345), selected for their proteolytic activity on myofibrillar proteins, were inoculated as starter cultures. Changes in the high ionic strength-soluble proteins of an external muscle (adductor) revealed in only 6 months higher proteolysis in the inoculated hams when compared to non-inoculated control hams. Proteolytic strains among the wild fungal population on non-inoculated control hams prevented from obtaining similar differences at the end of processing. However, inoculation with Pg222 and Dh345 led to higher levels for most free amino acids at the external muscle in fully dry-cured hams. In addition, the concentration for some of the more polar free amino acids (i.e. Asp, Glu, Ser and Gln) in inoculated hams was higher at external than at internal (biceps femoris) muscles. These promising results deserve further studies to know the impact of a selected fungal population on the volatile compounds and sensory properties of dry-cured ham.     

Effect of Penicillium chrysogenum and Debaryomyces hansenii on the volatile compounds during controlled ripening of pork loins

During ripening of meat products such as dry-cured ham, the moulds and yeasts that proliferate on the surface may contribute to flavour development. However, their contribution to volatile components of dry-cured meat products is not known. One strain each of Penicillium chrysogenum and Debaryomyces hansenii, selected from dry-cured ham by their proteolytic activity, were tested to determine their effect on the volatile compounds during ripening. Sterile pork loins were inoculated and ripened for 106 days. Volatile compounds collected with a Solid Phase Micro-Extraction (SPME) fibre were analysed by GC/MS. Inoculation of pork loins with P. chrysogenum lead to a decrease in compounds attributed to lipid oxidation and to an increase of compounds derived from free amino acids. Inoculation with D. hansenii seemed to favour the formation of complex alcohols.     

金华火腿传统工艺过程挥发性风味物质的分析研究

通过对金华火腿传统工艺过程晒后、中温发酵、高温成熟、成熟下架样品中挥发性风味物质的分析测定,研究传统工艺过程中挥发性风味物质的发展规律,结果表明:共有78种挥发性风味物质检出,醛、羧酸、醇、酯、酮、脂肪族和芳香族碳氢化合物、含硫化合物、吡嗪是主要成分;工艺工程中醛和酮的相对含量随温度的升高而逐渐降低,羧酸、酯、吡嗪和含硫化合物的相对含量逐渐增加。金华火腿的高温成熟工艺使来自于美拉德反应的羧酸有显著增加,这是金华火腿与地中海地区干腌火腿最显著的区别,也是金华火腿具有其独特风味的主要原因。     

Proteolytic activity of Penicillium chrysogenum and Debaryomyces hansenii during controlled ripening of pork loins

The role of micro-organisms on the ripening process of dry-cured ham, particularly with respect to proteolysis, is not clear. This is partially due to the lack of an adequate system to study changes on a sterile control meat product for long ripening times. Using a meat system based on sterile pork loins ripened under aseptic conditions for 106 days, the contribution to the proteolysis of two micro-organisms isolated from dry-cured ham has been established. Changes were studied by SDS-PAGE of sarcoplasmic and myofibrillar proteins, capillary zone electrophoresis (CZE) of low ionic strength-soluble nitrogen compounds, and HPLC of free amino acids. Debaryomyces hansenii Dh345 did not show any significant proteolytic activity. However, Penicillium chrysogenum Pg222 showed high proteolytic activity on myofibrillar proteins resulting in an increase in soluble nitrogen compounds. For this, P. chrysogenum Pg222 should be considered to be used as starter culture in meat products made using long ripening times.     

云南三川火腿和风干火腿挥发性风味成分分析

采用气相色谱-质谱(gas chromatography-mass spectrometry,GC-MS)对比分析不同发酵阶段(6、8、10、12个月)三川火腿和同一地区相同发酵阶段风干火腿中的挥发性风味成分,研究三川火腿、风干火腿挥发性风味成分的变化规律.结果表明:三川火腿共检出58种挥发性风味成分,其中醛类9种、醇...     

6 种安徽地方火腿不同部位特征香气的气相色谱-离子迁移谱表征

采用气相色谱-离子迁移谱（gas chromatography-ion mobility spectrometry,GC-IMS）技术建立6 种安徽地方火腿不同部位特征香气的快速分析方法。结果表明：GC-IMS仪检出107 种挥发性风味物质及其强度信息,但受限于数据库仅鉴定出48 种,包括单体和二聚体;样品中主要的挥发性风味物质包括11 种醇类（正丁醇、正戊醇、正丙醇、2-甲基丙醇、2-己醇等）、9 种酮类（丙酮、2-丁酮、3-羟基-2-丁酮、2-戊酮等）、12 种醛类（正丙醛、异丁醛、正戊醛、异戊醛、正己醛等）、10 种酯类（乙酸乙酯、丙酸乙酯、丁酸乙酯、异戊酸乙酯等）、2 种酸类（正丁酸和异戊酸）及4 种其他成分;采用主成分分析法有效分析了6 种安徽地方火腿不同部位特征香气的相似度,结果表明,不同的猪品种和取样部位之间有较大差异。GC-IMS可用于干腌火腿中挥发性风味物质的快速、全面检测,结合主成分分析可提供火腿品种及品质的信息。     

中西方干腌火腿风味成分比较及形成机理分析

风味对干腌火腿的质量十分重要 ,它与生产所用原料、生产工艺和参数密切相关。文中比较了金华火腿与欧洲几种著名火腿的风味成分 ,结果显示 ,中西方火腿的风味组成相似 ,醇、醛、酮、酯、含硫化合物、含氮化合物、烷、烯烃类物质是干腌火腿的共有成分 ,但各成分的含量在中西方火腿中存在明显差异 ,金华火腿中烷、烯烃含量最高 ,欧洲的几种火腿中醛类物质含量最高。文中同时分析了干腌火腿中各风味成分的特征和可能的形成机理。     

SPME-GC-MS结合ROAV分析腌制时间对大河乌猪火腿挥发性风味物质的影响

本研究旨在分析腌制时间对大河乌猪干腌火腿风味品质的影响,揭示干腌火腿的特征风味物质。将172只大河乌猪鲜腿分为4个组,采用传统方法加工后,每组随机抽取4只火腿,采用固相微萃取-气相色谱-质谱（Solid-Phase Microextraction-Gas Chromatography-Mass Spectrometry,SPME-GC-MS）技术并结合相对气味活度值（Relative Odor Activity Value, ROAV）法和主成分分析（Principal Component Analysis,PCA）法对大河乌猪火腿挥发性风味物质进行分析。结果表明:腌制15、18、21、24 d的挥发性成分的种类分别为57、57、54、41种,共鉴定77种同类挥发性成分;聚类分析表明不同腌制时间的大河乌猪火腿挥发性物质的组成及相对含量存在较大的差异;ROAV分析表明醛类和醇类对风味贡献最大;PCA表明1-辛烯-3-醇、异戊醛、正辛醛、双戊烯是不同腌制期火腿中含量变化最明显的挥发性物质。腌制时间对大河乌猪干腌火腿风味品质有一定影响,研究可为火腿品质控制及风味改良提供理论依据。     

金华火腿中挥发性风味物质形成过程及变化规律研究

以60只杂交猪后腿为原料,按照传统工艺加工金华火腿,采用固相微萃取(SPME)技术和气谱-质谱联用仪(GC-MS)分离、鉴定技术,研究了金华火腿股二头肌中挥发性风味化合物的形成变化规律。从6个不同加工时期的样品中共鉴定出191种物质,包括43种烃、31种醛、24种酮、21种酯、19种醇、17种羧酸、16种杂环化合物、5种内酯、5种含氯化合物、4种含硫化合物、2种酚、2种酸酐、1种酰胺和1种醚。其中醛类、醇类、烃类、酮类、酸类和酯类化合物含量较高,但各类风味物质的化合物种类和含量的变化规律各不相同。随着加工进行,肌肉中的挥发性化合物种类逐渐增多,但化合物总含量以晒腿结束和成熟中期最高。研究结果表明,与国外干腌火腿相比,金华火腿成品中羧酸、支链化合物、芳香族化合物及杂环化合物种类和含量较多,可能是金华火腿的风味特征。     

Changes in flavor compounds of dry-cured Chinese Jinhua ham during processing

Sixty experimental Jinhua hams were processed by a traditional method using green hams from local Liangtouwu cross-bred pigs. Samples of Biceps femoris were taken from five hams randomly at each of the key stages of production, i.e., green ham, end of salting, end of sun-drying, middle of loft-aging, end of loft-aging, post-aging-1 and post-aging-2. Analysis of flavor compounds showed 89 compounds at the green ham stage and at the end of salting, 90 at the end of sun-drying, 91 at the middle of loft-aging, 96 at the end of loft-aging, 93 at the post-age-1 and 94 at the post-age-2. The flavor compounds could be clustered in the following chemical families: alkanes and alkenes, aromatic hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids, esters, oxygenous heterocycle compounds, nitrogenous compounds, sulphur compounds, chloride compounds, amides, and terpenes. During processing, the concentrations of aldehydes and carboxylic acids increased; while the concentrations of alcohols, ketones, alkanes, alkenes, aromatic and cyclic hydrocarbons decreased. Sulphur compounds and pyrazines were formed and increased continuously during processing. In the final Jinhua ham, the contents of aldehydes, carboxylic acids, alcohols and ketones were 45.07%, 18.39%, 13.93% and 9.00% of the total flavor substances, respectively. The first principal component was a group dominated by five unbranched aldehydes; the second principal component was a group dominated by five branched and unbranched alcohols, two branched ketones, toluene, hexane and 4-nitrophthalamide. The two principal components explained 90.6% of the total flavor variance in Jinhua ham.     

金华火腿生产过程中风味成分的变化

取60条杂交猪后腿作为原料，按金华火腿传统生产工艺进行生产，分别在原料、盐后、晒后、成熟中期、成熟结束、后熟（1）、后熟（2）工艺段随机取5条腿的股二头肌作为样品进行风味成分检测．结果显示：原料腿和盐后腿中检出89种风味物质，晒后腿中检测出90种风味物质，成熟中期和成熟结束腿中分别检测出91种和96种风味物质，在后熟（1）和后熟（2）工艺段分别检测出93种和94种风味物质．这些成分可归类为：烷烯烃、芳香烃、醇、醛、酮、酸、酯、含氧杂环化舍物、含氮化合物、含硫化合物、含氯化舍物、酰胺和萜烯类等物质，其生产过程中的变化规律不同．在金华火腿产品的风味成分中，醛类占化舍物总数的45．07％，酸占18．39％，醇占13、93％，酮占9．00％．主成分分析显示，第一主成分主要由5种直链醛组成，第二主成分主要由5种直链醇和支链醇、2种支链酮、甲苯、已烷等组成．第一和第二主成分总计解释了金华火腿风味成分变化总方差的90．6％。     

Volatile compounds of dry-cured Iberian ham as affected by the length of the curing process

Volatile compounds from 10 dry-cured Iberian hams ripened for two different processing times, a prolonged traditional one (600 days) and a shortened process (420 days), were analysed by purge and trap coupled to gas chromatography-mass spectroscopy. Eighty-three compounds were identified which agreed with the major classes found in other ham types. The amount of methyl branched alkanes was much higher than in other dry-cured ham types, probably due to the feeding regime. The percentages of 2- and 3-methylbutanal were higher (p<0.0001 and p<0.0003, respectively) in the longer aged hams, whereas the amounts of some compounds from lipid oxidation decreased from 420 to 600 days aging. In agreement with these observations, 600-day hams had higher scores for those odour and flavour traits usually considered to be positive attributes and lower scores for rancidity. A positive and significant correlation between 2-methyl butanal and cured flavour was found.     

盘县火腿深度腐败的微生物及挥发性风味化合物表征

为建立有效的干腌火腿腐败预测机制，比较正常与腐败盘县火腿的理化特性，并应用高通量测序和固相微萃取-气相色谱-质谱联用技术揭示正常和腐败盘县火腿的微生物群落结构和挥发性风味化合物。结果表明，腐败火腿的理化特征在于较低的NaCl含量和较高的pH值、水分活度（aw）和水分含量。肠杆菌科（Enterobacteriaceae）微生物是造成盘县火腿腐败的优势菌群，包括norank_Enterobacteriaceae、unclassified_Enterobacteriaceae和沙雷氏菌属（Serratia）。冗余分析表明，水分含量和pH值可能是影响两种未知肠杆菌科细菌的重要因素，而沙雷氏菌属与NaCl含量密切相关。腐败火腿比正常火腿具有更高水平的酮类、烃类、含苯和含硫化合物。LEFSe分析将苯酚、苯乙醛、1-十五烯、二甲基二硫醚和3-甲基丁酸鉴定为腐败火腿的主体特征风味。微生物与风味之间的网络分析显示norank_Enterobacteriaceae和unclassified_Enterobacteriaceae是腐败火腿挥发性风味的主要贡献者。本实验结果可以为盘县火腿的品质控制提供一定理论依据。     

Development of volatile compounds during the manufacture of dry-cured "lacón," a Spanish traditional meat product

Volatile compounds were determined throughout the manufacture of dry-cured "lacón," a traditional dry-salted, and ripened meat product made in the north-west of Spain from the foreleg of the pig following a similar process to that of dry-cured ham. Volatiles were extracted by a purge-and-trap method and analyzed by gas chromatographic/mass spectrometry. One hundred and two volatile compounds were identified. In raw material, only 34 volatile compounds were found and at very low levels. The number of volatile compounds increased during processing. The substances identified belonged to several chemical classes: aldehydes (23), alcohols (9), ketones (15), hydrocarbons (37), esters (4), acids (3), furans (4), sulphur compounds (1), chloride compounds (1), and other compounds (4). Results indicated that the most abundant chemical family in flavor at the end of the manufacturing process was aldehydes, followed by hydrocarbons and ketones. Lipids were the most important precursor of flavor compounds of dry-cured "lacón."     

Effect of intensifying high‐temperature ripening on proteolysis,lipolysis and flavor of Jinhua ham

BACKGROUND: The flavor quality of dry‐cured ham comes from proteolysis, lipolysis and lipid oxidation, Maillard reaction and Strecker amino acid degradation. Intense proteolysis, lipolysis and lipid oxidation make major contributions to flavor development of dry‐cured ham. Increasing the temperature in fermenting and ripening could promote these reactions and accelerate flavor development in dry‐cured hams. The specific aroma flavor of Jinhua ham is developed only during long‐time high‐temperature ripening in July and August. Our objective was to effectively shorten the process time by intense high‐temperature ripening based on the flavor and quality features of traditional Jinhua ham. RESULTS: Muscle dehydration rate of 80‐day ripened hams (29.43 ± 1.16%) was higher than that of the traditional process (P < 0.05). The total free fatty acids in ripened hams of 45–80 days were all higher than that of traditional hams (P < 0.05) and the level of TBARS was significantly lower (P < 0.01). The flavor profile of modern‐processed hams was different from that of the traditional Jinhua ham. The contents of carboxylic acids and aldehydes were obviously higher than those of the traditional products (P < 0.05). The results of organoleptic evaluation for flavor and quality showed that 80‐day ripened hams reached the first‐grade level of traditional Jinhua ham. CONCLUSION: Long‐time (25–30 days) intensifying high‐temperature ripening (35–37 °C) could accelerate the proteolysis, lipolysis, lipids oxidation, flavor development and effectively shorten the process time based on the traditional flavor and quality features of dry‐cured ham. Copyright © 2009 Society of Chemical Industry     

Effect of selected strains of Debaryomyces hansenii on the volatile compound production of dry fermented sausage “salchichón”

Different biotypes of Debaryomyces hansenii, characterized by mitochondrial DNA (mtDNA) restriction analysis, were inoculated in dry fermented sausages to evaluate their influence as single starter culture on volatile compound generation throughout the ripening process. Similar evolution of physicochemical parameters and microbial population was observed in both uninoculated and inoculated sausages. The tested biotypes modified the volatile compound profile of sausages specially in esters, branched alcohols and aldehydes. The biotype of D. hansenii with the E mtDNA restriction pattern is the most suitable to be used as starter culture since it produced volatile compounds involved in flavour development of dry-cured meat products such as 3-methylbutanol, 3-methylbutanal and 2-propanone. Moreover, the use of D. hansenii strains with the B, C2 and E mtDNA restriction patterns, as a mixed starter culture, should be also considered to generate low amount of sulphur compounds in dry-cured meat products.     

传统干腌火腿中霉菌菌相构成及其安全性评价

对国内外传统干腌火腿中霉菌菌相组成、作用等方面进行了综述,并阐述了传统干腌火腿中霉菌的安全性评价。产毒霉菌的存在会给火腿带来潜在的危险性,因此通过对自然生长的霉菌分离纯化,筛选有益于火腿发色、成熟、产香和外观的菌株作为发酵剂,这是解决传统火腿制品安全性的一条重要途径。     

Biochemical changes during processing of traditional Jinhua ham

Jinhua ham is the most famous traditional meat product of China and one of the most famed dry-cured hams in the world. Its processing consists of six stages: green ham preparation, salting, washing and sun-drying and shaping, ripening, and post-ripening. Intense proteolysis and lipolysis occur during processing period. As a result, the content of free amino acids in final ham products is 14-16 times that of green ham, and 191 volatile compounds have been identified during processing, which make a major contribution to the flavor of Jinhua ham.