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Determination of sulfur and nitrogen compounds during the processing of dry fermented sausages and their relation to amino acid generation

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Determination of sulfur and nitrogen compounds during the processing of dry fermented sausages and their relation to amino acid generation

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... As regards the effect of fat partial replacement, also in this case, significant differences (P < 0.001) were recorded among the batches, where T2 sausages showed the lowest total nitrogen compounds content, while CON and T1 samples recorded similar values. This group of compounds could play a key role in the formation of sausage aroma due to its low odor threshold values and unique olfactive notes (Corral et al., 2016). Some authors hypnotized that these compounds could take origin from the addition of potassium nitrate and sodium nitrite during the sausages manufacturing (Corral et al., 2016). ...
... This group of compounds could play a key role in the formation of sausage aroma due to its low odor threshold values and unique olfactive notes (Corral et al., 2016). Some authors hypnotized that these compounds could take origin from the addition of potassium nitrate and sodium nitrite during the sausages manufacturing (Corral et al., 2016). On the other hand, other researchers commented that the use of nitrite is not directly correlated to aromatic compounds, but its lack could favor lipid oxidation processes, covering the odor of sulfur compounds accountable for the characteristic aroma of nitrite-ripened meat products (Thomas et al., 2014). ...
... On the other hand, other researchers commented that the use of nitrite is not directly correlated to aromatic compounds, but its lack could favor lipid oxidation processes, covering the odor of sulfur compounds accountable for the characteristic aroma of nitrite-ripened meat products (Thomas et al., 2014). Furthermore, some authors affirmed that the origin of these substances could derive from Strecker degradation processes from a nitrogen source, as amino acids (Corral et al., 2016). ...
Article
This study aimed to evaluate the influence of partial replacement of animal fat by oil mixture emulsion hydrogels on the quality properties of dry-fermented foal sausages. Three batches were elaborated: control (CON) – 100% of pork fat; treatments 1 and 2 (T1 and T2) – 50% of pork fat was replaced by oil mixture emulsions, tigernut (T1) or sesame oils (T2) blended with algal oil. Lipid reformulations reduced (P < 0.001) fat (36.91% vs. about 30%, for CON and reformulated samples, respectively), and moisture contents (33.57% vs. about 28%, for CON and reformulated samples, respectively), while darker sausages were obtained. These changes in the both, fat and moisture contents, have an important influence on the texture parameters, since reformulated samples presented higher values of hardness (283-317 N) than control samples (152 N). Both oil emulsion hydrogels favored a decrease (P < 0.001) of saturated fatty acids (34.16 vs. 30 g/100 g of fat), an increase (P < 0.001) of mono- (T1) and polyunsaturated (T2) fatty acids (depending on the batch), and an improvement of all health indices as omega-6/omega-3 (n-3/n-6) and polyunsaturated fatty acids/ saturated fatty acid ratios (PUFA/SFA), atherogenic (AI) and thrombogenic (TI) indices and hypocholesterolaemic/hypercholesterolaemic ratio (h/H). T2 seemed to reduce (P < 0.001) the lipid oxidation in the samples, while T1 presented the highest values. On the other hand, the terpenes and terpenoids were the most abundant volatile compounds (VOCs) found in all sausages, mainly due to the use of pepper as flavoring spice. Several differences were observed on the content of different individual VOCs (hydrocarbons, acids, alcohols, aldehydes, etc.) and also in the total VOCs content, due of both, differences in lipid oxidation processes (in accordance with TBARS values) and also the moisture and fat content of the samples. Nevertheless, consumer acceptability resulted to be unaffected (T1) or improved (T2) by the fat reformulation. Thus, overall results pointed out that the use of T2 emulsion hydrogel as a partial animal fat replacer could be a promising strategy to achieve healthier dry-cured foal sausages with high consumers’ approval.
... Most of the identified compounds were also detected in fermented sausages by other authors [28,[52][53][54][55][56][57][58][59]. Some compounds showed high standard deviations, as observed by Schimidt and Berger [60], Moretti et al. [61], Tabanelli et al. [54] and Montanari et al. [56] in products similar to dry fermented sausages. ...
... Except for the β-pinene terpene (from the seasonings), the compounds hexanal, hexanol, pentanal, 2- propanone, ethanol, and 2-butanone were found in decreasing order, totaling > 80% of peak area. Hexanal, hexanol, and pentanal are mainly derived from lipid oxidation [57,58] and are associated with notes of grass, green leaves and rancid odor [28], while 2-propanone, ethanol and 2-butanone originate mainly from the catabolism of carbohydrates [29]. Lipid oxidation contributes significantly to the aroma of fermented sausages by releasing compounds from different chemical classes, mainly aldehydes, methyl ketones, and alcohols [63]. ...
Article
Ultrasound (US) is an emerging technology capable of affecting enzymes and microorganisms, leading to the release of amino acids and the formation of volatile compounds. The effect of different exposure times (0, 3, 6, and 9 min) of US (25 kHz, 128 W) on the proteolysis and volatile compounds of dry fermented sausages during processing (day 0 and 28) and storage (day 1 and 120) was investigated. Lower alanine, glycine, valine, leucine, proline, methionine, and tyrosine levels were observed at the beginning of manufacture for the sample subjected to 9 min of US (p <0.05) when compared to the control. During the storage period, the samples subjected to US exposure for 3 and 6 min exhibited higher free amino acid levels. A greater formation of hexanal, pentanal, and hexanol was observed in the US-treated samples when compared to the control (p <0.05), as well as other derivatives from the oxidation reactions during the storage. The use of US (25 kHz and 128 W) in the manufacture of dry fermented sausages can affect the proteolysis and the formation of compounds derived from lipid oxidation during the storage.
... The different dry cured meat model systems were prepared according to the dry fermented sausages composition [40,41] regarding the concentration of additives and free amino acids at the initial (I), 1st drying (1D) and 2nd drying (2D) stages of the process ( Table 2). Model systems were prepared in 0.2 mM phosphate buffer, and their composition included nitrate, nitrite, NaCl, sodium ascorbate and glucose at the concentrations included in Table 3. a w of the model systems at the different processing stages was adjusted with glycerol. ...
... Samples from each media and temperature were taken at 0, 5, 11, 15, 20, 25, 29 and 35 days for physicochemical analysis, volatiles and amino acid composition. Table 2. Composition in amino acids (mg/100 mL) of each model system according to the concentration of amino acids reported in different ripening stages of dry fermented sausages [40,41]. ...
Article
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Flavor is amongst the major personal satisfaction indicators for meat products. The aroma of dry cured meat products is generated under specific conditions such as long ripening periods and mild temperatures. In these conditions, the contribution of Maillard reactions to the generation of the dry cured flavor is unknown. The main purpose of this study was to examine mild curing conditions such as temperature, pH and aw for the generation of volatile compounds responsible for the cured meat aroma in model systems simulating dry fermented sausages. The different conditions were tested in model systems resembling dry fermented sausages at different stages of production. Three conditions of model system, labeled initial (I), 1st drying (1D) and 2nd drying (2D) and containing different concentrations of amino acid and curing additives, as well as different pH and aw values, were incubated at different temperatures. Changes in the profile of the volatile compounds were investigated by solid phase microextraction and gas chromatography mass spectrometry (SPME-GS-MS) as well as the amino acid content. Seventeen volatile compounds were identified and quantified in the model systems. A significant production of branched chain volatile compounds, sulfur, furans, pyrazines and heterocyclic volatile compounds were detected in the model systems. At the drying stages, temperature was the main factor affecting volatile production, followed by amino acid concentration and aw. This research demonstrates that at the mild curing conditions used to produce dry cured meat product volatile compounds are generated via the Maillard reaction from free amino acids. Moreover, in these conditions aw plays an important role promoting formation of flavor compounds.
... The degradation of meat proteins produces small peptides and free amino acids. Many studies reported increases in total amino acid content during sausage fermentation (9,23,24). In this study, most amino acids increased after fermentation, indicating production of proteins from meat by enzymatic degradation. ...
Article
A GC-MS based metabolomic study was performed to understand metabolic changes during sausage fermentation and to investigate how the incorporation of pineapple affects the metabolic profiles of fermented sausages. Principal component analysis models showed clear metabolic differences among the fermented sausages according to the fermentation periods and the pineapple addition. Increased amounts of amino acids and organic acids except for citric acid, along with decreased levels of sugars were observed after fermentation. Higher levels of sugars and citric acid in the pineapple supplemented sausages dramatically decreased during the early stage of fermentation. The contents of lactic acid, phosphoric acid, succinic acid, ribonic acid, valine, leucine, isoleucine, glycine, threonine, glutamic acid, glucose, and sucrose were significantly increased in the 2% pineapple addition sausages. GC-MS and PCA analytical methods provide a new approach to understand of the metabolic changes in fermented sausages during fermentation.
... pH variations during maturation are usually related to bacterial lactic acid production [29,40]. Very recently, a positive correlation between pyrazine formation, which contributes to aroma, and alkaline pH, was reported [41]. Meanwhile, a low pH during fermentation is usually favored to inhibit growth of unwanted bacteria [42]. ...
Article
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Yeasts, filamentous fungi and bacteria colonize the surface of fermented sausages during the ripening process. The source of this microbiota is their surrounding environment, and it is influenced by their maturing conditions and by starter cultures. Debaryomyces hansenii has been previously isolated from several dry-cured meat products, and it has been associated with the lipolytic and proteolytic changes that occur in these products, which influence their taste and flavour. In this work, the yeast microbiota present in casing from different meat products ("lomo", "chorizo" and "salchichón") from the Valle de los Pedroches region, South-Spain, were isolated for the first time. D. hansenii was by far the most abundant species in these products, as all 22 different isolates selected were identified as D. hansenii by biochemical and/or molecular methods. In contrast, no yeasts were found in the meat batter. Our data constitute the first study on the yeasts present in "lomo" sausages and particularly on the highly appreciated "Valle de los Pedroches" ones. Furthermore, the resistance of these isolates to different pH, temperatures and saline stress was studied, together with their catabolic characteristics. Based on those results, some isolates are proposed as valuable candidates for starter cultures that could improve both the manufacture and the flavor of this dry-cured meat products, together with the understanding of new mechanisms involved in stress tolerance. Applied medium-scale industrial tests are currently in progress.
... 33 The mustard leaves contain glucosinolates, which can be degraded into some volatile components, such as sulfur-containing compounds, during the formation of cuocai. 34 Cruciferae plants contain glucoside, which contains sulfur and nitrogen, and they can be hydrolyzed to characteristic flavor substances in the process of fermentation. It has been found that all fermented cabbages contained sulfur compounds, including dimethyl disulfide, dimethyl trisulfide, and dimethyl tetrasulfide, which were favorable for the formation of characteristic flavors such as fresh-garlic-like and cooked cabbage-like odor of mustard. ...
Article
Background: To improve the characteristic and safety of traditional cuocai, the selection and us of mixed starter cultures is important. This work was aimed to isolate the main indigenous LAB and yeast species from spontaneous fermented mustard leaves, and they were used as starter cultures to ferment mustard leaves. Results: Five predominant lactic acid bacteria (LAB) including Q-1 (Enterococcus faecalis), G-1 (Lactobacillus plantarum), G-3 (Lactobacillus pentosus), G-2 and G-4 (Lactobacillus buchneri)strains and two yeast strains including J-1 (Issatchenkia orientalis) and J-2 (Issatchenkia occidentalis)strains were isolated from cuocai. From the results, Lb. plantarum and I. orientalis strains exhibited strong growth ability, fast acidification and potent low-pH tolerance. Therefore, they were chosen as the mixed starter cultures to ferment mustard leaves. During the process of culture-dependent fermented mustard leaves, the changes of acidity, TCP, total sugar were similar as those of culture-independent fermented mustard leaves, while the nitrite content of culture-dependent fermented mustard leaves was significantly lower than that of culture-independent fermented cuocai. According to GC-MS analysis, the main volatile flavor compounds of fermented mustard leaves were alcohols, aldehydes, esters, and sulfides. There was no significant difference of volatile flavor compounds between the processes of culture-dependent and culture-independent fermentations. Conclusion: Therefore, it was suggested that Lb. plantarum and I. orientalis strains could be used to ferment cuocai instead of the traditional ferment method to control the quality and shelf safety of cuocai.
... Terpenoids, phenylpropens, and benzothiazole persisted at the end of the shelf life, dominating the VOCs profile of E samples as well. The main source of benzothiazole seems to be the ingredients of sausage, since the molecule was found already in S samples and in the mixture of spices as well (data not shown), although it may also be generated by degradation of thiamine or sulfur containing free amino acids (Corral et al., 2016). The volatiles profile of the majority of E samples was characterized by acetic acid, 2,3-butanediol, and pentanal, undetected in the initial samples. ...
Article
Ten lots of industrial raw sausages in modified atmosphere (CO2 30%, O2 70%), produced in the same plant over 7 months, were analyzed at the day after production (S samples) and at the end of shelf life (E samples), after 12 days storage at 7 °C to simulate thermal abuse. Quality of the products was generally compromised by storage at 7 °C, with only 3 E samples without alterations. During the shelf life, the pH decreased for the accumulation of acetic and lactic acids. A few biogenic amines accumulated, remaining below acceptable limits. The profile of volatile compounds got enriched with alcohols, ketones, and acids (e.g. ethanol, 2,3-butanediol, 2,3-butandione, butanoic acid) originated by bacterial metabolism. Throughout the shelf life, aerobic bacteria increased from 4.7 log to 6.6 log cfu/g, and lactic acid bacteria (LAB) from 3.7 to 8.1 log cfu/g. Staphylococci, enterobacteria, and pseudomonads passed from 3.7, 3.0, and 1.7 to 5.5, 4.8, and 3.0 log cfu/g, respectively. Dominant cultivable LAB, genotyped by RAPD-PCR, belonged to the species Lactobacillus curvatus/graminis and Lactobacillus sakei, with lower amounts of Leuconostoc carnosum and Leuconostoc mesenteroides. Brochothrix thermosphacta was the prevailing species among aerobic bacteria. The same biotypes ascribed to several different species where often found in E samples of diverse batches, suggesting a recurrent contamination from the plant of production. Profiling of 16S rRNA gene evidenced that microbiota of S samples clustered in two main groups where either Firmicutes or Bacteroidetes prevailed, albeit with taxa generally associated to the gastro-intestinal tract of mammals. The microbial diversity was lower in E samples than in S ones. Even though a common profile could not be identified, most E samples clustered together and were dominated by Firmicutes, with Lactobacillaceae and Listeriaceae as the most abundant families (mostly ascribed to Lactobacillus and Brochothrix, respectively). In a sole E sample Proteobacteria (especially Serratia) was the major phylum.
... The main advantages of SPME are its simplicity, low cost, ease of automation, and in situ sampling [12]. SPME coupled with GC-MS has been used widely to evaluate the flavor chemical profiles of volatile aromas produced by a wide variety of substances, including fermented milk [13,14], the fruit and sap of mango cultivars [15], grapes and wine [16], dry fermented sausage [17], and alcoholic beverages [18]. ...
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Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus are key factors in the fermentation process and the final quality of dairy products worldwide. This study was performed to investigate the effects of the proportions of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus isolated from traditionally fermented dairy products in China and Mongolia on the profile of volatile compounds produced in samples. Six proportional combinations (1:1, 1:10, 1:50, 1:100, 1:1000, and 1:10,000) of L. delbrueckii subsp. bulgaricus IMAU20401 to S. thermophilus ND03 were considered, and the volatiles were identified and quantified by solid-phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS) against an internal standard. In total, 89 volatile flavor compounds, consisting of aldehydes, ketones, acids, alcohols, esters, and aromatic hydrocarbons, were identified. Among these, some key flavor volatile compounds were identified, including acetaldehyde, 3-methylbutanal, acetoin, 2-heptanone, acetic acid, butanoic acid, and 3-methyl-1-butanol. The of L. delbrueckii subsp. bulgaricus IMAU20401 to S. thermophilus ND03 influenced the type and concentration of volatiles produced. In particular, aldehydes and ketones were present at higher concentrations in the 1:1000 treatment combination than in the other combinations. Our findings emphasize the importance of selecting the appropriate proportions of L. delbrueckii subsp. bulgaricus and S. thermophilus for the starter culture in determining the final profile of volatiles and the overall flavor of dairy products.
... They accounted for one third of the compounds forming the GC-O profile and had high DF values. Among them, 2 acetyl-1-pyrroline and methional are considered as the most potent odor active compounds in dry-fermented sausages (Corral, Leitner, Siegmund, & Flores, 2016;Söllner & Schieberle, 2009). Also 3-methylbutanoic acid is considered a potent aroma contributor, giving cheesy, lactic and fatty notes , while 2,5-dimethylpyrazine is related to meaty and cooked potatoes notes. ...
... Terpenoids, phenylpropens, and benzothiazole persisted at the end of the shelf life, dominating the VOCs profile of E samples as well. The main source of benzothiazole seems to be the ingredients of sausage, since the molecule was found already in S samples and in the mixture of spices as well (data not shown), although it may also be generated by degradation of thiamine or sulfur containing free amino acids (Corral et al., 2016). The volatiles profile of the majority of E samples was characterized by acetic acid, 2,3-butanediol, and pentanal, undetected in the initial samples. ...
Article
Fourteen lots of cooked ham in modified atmosphere packaging (CH) were analyzed within a few days from packaging (S) and at the end of the shelf-life (E), after storage at 7 °C to simulate thermal abuse. Five more lots, rejected from the market because spoiled (R), were included in the study. Quality of the products was generally compromised during the shelf life, with only 4 lots remaining unaltered. Analysis of 16S rRNA gene amplicons resulted in 801 OTUs. S samples presented a higher diversity than E and R ones. At the beginning of the shelf life, Proteobacteria and Firmicutes dominated the microbiota, with Acinetobacter, Brochothrix, Carnobacterium, Lactobacillus, Prevotella, Pseudomonas, Psychrobacter, Weissella, Vibrio rumoiensis occurring frequently and/or abundantly. E and R samples were dominated by Firmicutes mostly ascribed to Lactobacillales. It is noteworthy the appearance of abundant Leuconostoc, negligible in S samples, in some E and R samples, while in other LAB were outnumbered by V. rumoiensis or Brochothrix thermosphacta. The microbiota of spoiled and R samples could not be clustered on the basis of specific defects (discoloration, presence of slime, sourness, and swollen packages) or supplemented additives. LAB population of S samples, averaging 2.9 log10(cfu/g), increased to 7.7 log10(cfu/g) in the E and R samples. Dominant cultivable LAB belonged to the species Lactobacillus sakei and Leuconostoc carnosum. The same biotypes ascribed to different species where often found in the corresponding S and R samples, and sometime in different batches provided from the same producer, suggesting a recurrent contamination from the plant of production. Consistently with growth of LAB, initial pH (6.26) dropped to 5.74 in E samples. Volatiles organic compound (VOCs) analysis revealed that ethanol was the major metabolite produced during the shelf life. The profile of volatile compounds got enriched with other molecules (e.g. 2-butanone, ethyl acetate, acetic acid, acetoin, butanoic acid, ethyl ester, butanoic acid, and 2,3-butanediol) mainly ascribed to microbial metabolism.
... The acceptability of fermented meat products by the consumer is strongly influenced by the final product flavor (Kaban 2010) that is composed of taste and aroma of which the latter has priority in food evaluation. Volatile compounds produced during the fermentation process are responsible for the aroma of a meat product (Corral et al. 2016). The taste of fermented meat products is mainly due to production of low molecular weight compounds such as non-volatile (e.g., amino acids, peptides, lactic acid, and salt) and volatile compounds arising from amino acid breakdown, sugar catabolism, and lipid oxidation (Todorov et al. 2017). ...
Article
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Aroma and aroma-active compounds of the heat-treated Turkish sausages obtained from beef, turkey, and chicken meats were studied. Aroma compounds were isolated by using solvent-assisted flavor evaporation and analyzed by gas chromatography/mass spectrometry-olfactometric (GC-MS-O) for the first time. A total of 47, 63, and 64 aroma compounds, including esters, terpenes, terpenols, aldehydes, phenols, ketones, acids, alcohols, lactones, furans, sulphur compounds and pyrazines, were identified and quantified in the beef, turkey, and chicken sausages, respectively. The most prominent differences between the sausage samples were as follows: (E)-sabinene hydrate, β-cubenene, 2-hexanol, 5-methyl-2-heptanol, 2-heptanol, 2-nonanol, 4-methyl-3-hexanol, and heptanoic acid were detected only in chicken sausage samples; (Z)-p-mentha-1(7)8-dien-2-ol, dimethylallyl alcohol, 1,2-ethanediol, furfuryl alcohol, furfural, 2-ethyl-6-methylpyrazine, trimethyl pyrazine, and 2(5H) furanone were detected only in turkey sausage samples; and 2-butoxyethanol, octanoic acid and nonanoic acid were detected only in beef sausage samples. The aroma-active compounds of sausages were elucidated by using aroma extract dilution analysis (AEDA) for the first time. A combined total of 31 different aroma-active compounds were detected. The aroma-actives with the greatest flavor dilution (FD) factors in beef (FD: 1024 and odor activity value (OAV): 178.07) and chicken (FD: 2048 and OAV: 262.63) sausages were γ-terpinene and in turkey (FD: 2048 and OAV: 353.86) sausages were linalool. Key words: Turkish sausages, aroma-active compounds, OAV, GC-MS-O, SAFE
... Although the contents of other heterocyclic compounds were lower in roasted sesame seeds, they could made important contributions to the flavor characteristics because of their low odor threshold, especially S-heterocycles (Mottram & Mottram, 2002). For example, thiophenes and thiazoles, with low odor thresholds and roasted and scorched flavors (Corral, Leitner, Siegmund, & Flores, 2016), were detected in the roasted sesame seeds and played an important role in the aroma profiles. In the present study, all the S-heterocycles and most of the N-heterocycles were detected after 12 min of roasting, suggesting that the formation of these compounds is more complicated. ...
Article
Background and objectives The changes in polar metabolites and volatiles in sesame seeds during roasting were analyzed to provide new information for the formation mechanism of sesame oil aroma. Findings The results showed that the typical sesame aroma components, heterocyclic compounds, increased with the extension of the roasting time and reached 43.78% at 12 min. However, the proportion of aliphatics and terpenoids decreased with the roasting time. In addition, the main polar metabolites in sesame seeds, free amino acids and monosaccharides, continually decreased from 497.14 μg/g and 268.85 μg/g in raw seeds to 144.59 μg/g and 7.52 μg/g in 12 min‐roasted seeds, respectively. Conclusions Based on the changes in specific polar metabolites and volatile compounds, it could be inferred that pyrazines mainly generated through Maillard reaction with Ala and glucose as the possible primary substrates. While S‐heterocycles might be mainly formed through the thermal degradation of proteins and subsequent reactions. Significance and novelty The results of this study provide important information and new details for the aroma formation process of sesame seeds during roasting, and would provide a reference for the study and optimization of sesame roasting and oil extraction processes, as well as the development of sesame seed products. In addition, relevant information can also provide clues for the artificial synthesis of sesame seed aroma components. This article is protected by copyright. All rights reserved.
... There are several influential factors in this process, such as the type of raw materials, the amount of additives, the quantity of proteins, and lipids [8]. Hydrolysis of proteins and lipids causes the release of amino acids and fatty acids, which are used by microorganisms as food [9]. Microbiological enzymes degrade free fatty acids into short-chain fatty acids through lipid β-oxidation reactions; these short-chain fatty acids contribute to the pungent smell of meat [10]. ...
Article
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Beef jerky is a traditional fermented meat product from Inner Mongolia, handcrafted by artisans. We investigated the bacteria of the microbial community, volatile flavor components, and biogenic amines of Inner Mongolia beef jerky via high-throughput sequencing, solid-phase microextraction with gas chromatography–mass spectrometry, and high-performance liquid chromatography, respectively. Thirty-three bacteria were identified, predominantly from the genera Pseudomonas (45.4%), Ralstonia (13.4%), and Acinetobacter (7.3%). Fifty-nine volatile flavor compounds and eight biogenic amines were detected. Based on Spearman’s correlation coefficient, 20 bacterial genera were significantly associated with the dominant volatile compounds in the beef jerky samples (p < 0.05). The results demonstrated that beef jerky may be toxic due to cadaverine, putrescine, and histamine; moreover, the amounts of putrescine and cadaverine were positively correlated with the abundance of unclassified_f_Enterobacteriaceae (p < 0.05). These findings shed light on the formation of the microbial community, flavor components, and biogenic amines of beef jerky, thereby providing a basis for improving its quality.
... In the literature, the determination of sulfur compounds is carried out using several analytical techniques [15], such as titration [16][17][18], calorimetry [19], gravimety [20], potentiometry [21], X-ray fluorescence [22,23], and gas chromatography [24][25][26][27]. However, these methods require a lot of time to carry out the analyses and are tedious [13]. ...
Article
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Butanethiol is a contaminant of aviation biokerosene, and its monitoring is of great importance to evaluate the quality of this biofuel. In this work, the elucidation of the electrochemical behavior of butanethiol was carried out using a glassy carbon electrode in order to contribute to the development of future electroanalytical methods to determine this contaminant in aviation biokerosene. The results obtained showed that the electrooxidation of butanethiol is controlled by diffusion and occurs irreversibly in two steps: a well-defined anodic peak at 1.2 V vs. Ag/AgCl (3.0 mol L−1) and an ill-defined anodic wave at 1.4 V vs. Ag/AgCl (3.0 mol L−1). The Randles-Sevcik and Tafel equations were used to determine the diffusion coefficient (D) and electronic transfer coefficient (α), respectively. In addition, the mechanism of the butanethiol oxidation reaction was proposed based on the number of protons and electrons involved. Good linear relations were obtained between peak currents and butanethiol concentrations by cyclic voltammetry and differential pulse voltammetry. As a proof of concept, the glassy carbon electrode was applied to determine the butanethiol molecule in an aviation biokerosene sample. The results obtained showed that this electrode has remarkable accuracy when applied toward the determination of butanethiol. Graphical Abstract
... For example, free sugars (e.g., glucose, fructose and mannitol) provide sweetness, lactate and acetate are sour, and amino acids underlie umami (Datta & Henry, 2007;Wisselink, Weusthuis, Eggink, Hugenholtz, & Grobben, 2002). Furthermore, some of amino acids might be converted to flavor compounds (e.g., alcohols, aldehydes, acids, esters and sulfur compounds) (Corral, Leitner, Siegmund, & Flores, 2016;Smid & Kleerebezem, 2014). ...
... As far as the authors can determine little or no published work exists in relation to DE, LLE or SAFE on beef. Studies using LLE in pork [52,53] and SAFE in stewed pork [54], heat treated sausages [55] and dry fermented sausages [56] exist. Only SDE has been used in heated beef [57], as well as in chicken [58] and chicken breast meat [59]. ...
Article
The aroma of meat is an integral part of flavor and therefore an essential element for consumer acceptance. Aroma compounds are challenging to extract, concentrate, separate, identify, and quantify due to the complexity of meat. A wide range of volatile compounds of different properties (molecular weight, polarity, vapor pressure) are present in raw meat at varying concentrations, and further exacerbated post cooking due to the creation of additional volatiles through mainly Maillard reactions and lipid oxidation reactions. The volatiles identified in cooked meats include hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids, esters, lactones, ethers, heterocyclic constituents, and sulfur‐/halogen‐containing components. From published research, some of the key volatiles influencing cooked beef/pork flavor include hexanal, octanal, nonanal, 1‐nonanal, (E,E)‐2,4‐decadienal, methional, 3‐methyl‐1‐butanol, methanethiol, 2‐furfurylthiol, 2‐metyl‐3‐furanthiol, 3‐mercapto‐2‐pentanone, 4‐hydroxy‐2,5‐dimethyl‐3‐(2H)‐furanone, 1‐penten‐3‐one, 2‐pentyl‐furan, N‐morpholinomethyl‐isopropyl=sulfide, and methyl butyrate. GC‐MS is the method of choice for their separation and identification. The technical options available have never been greater to elucidate these key volatiles impacting sensory perception. This review presents a summary of the main extraction/concentration techniques, highlighting their potential pros and cons, how advances in two‐dimensional gas chromatography may help elucidate more key aroma compounds, and outlines the benefits of olfactometry to determine the main odor‐active volatiles in beef and pork.
... The degradation of proteins by proteolysis produces a source of amino acids as well as small peptides that participate in the generation of aroma compounds (Corral, Leitner, Siegmund, & Flores, 2016;Flores & Olivares, 2014). Myofibrillar and sarcoplasmic proteins are hydrolysed by endogenous and microbial proteases (endo-and exoproteases) (Toldrá & Flores, 1998). ...
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Traditional fermented meat sausages are produced around the world due to their convenience and sensory characteristics which are responsible for their high acceptability. They constitute a cultural heritage as shown by the high diversity of products around the world. Recent trends are addressing issues regarding innovation in their formulation by reduction of salt, fat and additives (curing salts). However, the current trend towards a reduction in the consumption of meat has produced an increase in the formulation of meat product analogues. This trend is the main focus of producers to offer new attractive products to consumers even though the aroma profile of traditional fermented meat sausages is not reached. In this manuscript, we review and discuss the chemistry of aroma formation in traditional fermented meat sausages in contrast to the potential of plant-based ingredients used in meat analogues.
... This interesting finding could be helpful to further understanded the biosynthesis of C8 compounds in mushrooms. Volatile sulfur compounds are important aroma-active compounds in vegetables and processed meats, and they can offer unique aroma in L. edodes differing from many other commonly consumed mushrooms [22,32]. As shown in Table 1, the contents of sulfur compounds in mushrooms decreased after the drying process. ...
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... The authors concluded that both polycyclic aromatic hydrocarbons and potentially toxic metals were found at levels that called for caution on the part of consumers to prevent health infarctions. These statements are confirmed by the methodology of Corral et al. (2016) who identified and quantified seventeen sulfur and nitrogen compounds in dry fermented sausages. Among them, 2-acetyl-1-pyrroline was the most potent odor active compound, followed by methional, ethylpyrazine and 2,3-dihydrothiophene characterized by toasted, cooked potato, and nutty notes. ...
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... The content of FAAs in broth significantly depend on the degradation of proteins in raw materials versus the reaction of FAA transformation (oxidation, Maillard reaction, Strecker degradation, etc.) (Elmore et al., 2004;Estevez, 2011). During the beginning of the QRBC process (Step 1: Degradation stage), large amounts of FAAs were produced by the hydrolysis of muscle proteolytic enzymes and amino peptidases while FAAs started participating in the Maillard reactions to form volatile compounds (Corral et al., 2016). ...
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Flavor is an important attribute of food and a major factor that determines the acceptability of food to consumers. Therefore, achieving a comprehensive and accurate analysis of food flavor could provide insights into continuous exploration in food research. In recent years, the generation of comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) with excellent separation ability has successfully revealed the aroma compound composition in a complex food matrix. Meanwhile, GC×GC-MS combined with gas chromatography-olfactometry (GC-O) has been further developed in the combination of instrumental analysis and sensory evaluation. In this paper, a comprehensive review of the generation and development of GC×GC-MS was reported. Simultaneously, the principle of GC×GC-MS and the application progress of GC×GC-MS combined with GC-O in the flavor analysis field in recent years were summarized. Last, a new switchable system between GC-O-MS and GC×GC-O-MS (SGC/GC×GC-O-MS) was proposed to promote its further application in the flavor analysis of complex matrix foods.
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2-Acetyl-1-pyrroline is an aroma compound that gives aromatic rice its characteristic flavor. This compound is present either naturally in various food sources or is generated during certain processing methods, as reported in a number of studies. This review focuses on several sources of 2-acetyl-1-pyrroline, including aromatic rice, and the factors, including chemical and genetic parameters, affecting the formation of 2-acetyl-1-pyrroline. Extensive work has been conducted on agricultural parameters, post-harvest processing, storage, and cooking methods, influencing the concentrations of 2-acetyl-1-pyrroline in different food commodities. This article is an attempt to emphasize the importance of this compound in the food industry as a major aroma compound.
Chapter
The use of olfactometry in aroma analysis has allowed the identification of those volatiles occurring in a food that contribute to its aroma. It is well known that only a small portion less than 3-5% of the thousands of volatile compounds identified in foods contribute to the aroma. Olfactometry is a technique used for the assessment of odour performance, coupled to a gas chromatograph that allows the separation of compounds, prior to their assessment as done by a human detector, the nose. The goal of using gas chromatograph with a olfactometry detector (GC-O) in food industry may have different approaches, but it is the most frequently used to reveal the composition of the volatile compounds with aroma impact in the food, and to reformulate food aromas. Other applications may be the identification of off-flavours, control production processes, and control of raw materials.
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The goal of this study was to confirm and acquire more information about the nitrogen and sulfur compounds existing in the volatile profile of dry fermented sausages from the addition of precursors (proline, ornithine and thiamine), and their role in sausage aroma. To this end, the precursors were added to the formulation of sausages, which were submitted to a fermentation and drying process. The sausage aroma was analyzed by olfactometry technique and Free Choice Profile sensory analysis. The results showed that the addition of precursors impacted the aroma, and reduced the level of oxidation in the final sausages while microbial differences were mainly observed in Orn-sausages. Among the aroma compounds detected only 2-methyl-3-(methylthio)furan verified the effect of thiamine supplementation and the impact on the cured and savoury odours detected in Thia-sausages by Free Choice profile sensory analysis, while no clear effect could be attributed to specific volatile compounds in the nitrogen supplemented sausages.
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Background: The use of boar back fat for processing of fermented sausages may cause the presence of abnormal odours. In dry-cured products, ripening time is essential to develop the sensory characteristics. Yeast has been proposed as an alternative to mask boar taint odour through its metabolic activity but it is necessary to elucidate which mechanisms are involved. The aim is to study the effect of D. hansenii inoculation on the lipolysis process and generation of aroma compounds in fermented sausages manufactured with boar back fat at two different ripening times. Results: D. hansenii inoculated sausages had a higher degree of lipolysis as demonstrated by higher content of free fatty acids, ester compounds and branched aldehydes which contribute the fruity odour. The increase in lipolysis produced by D. hansenii inoculation was not followed by an increase in oxidation during processing possibly due to the metabolic activity of yeast. The effect of back fat type was scarcely appreciated whereas ripening time had a stronger effect on sausage. Boar sausages were characterized by a lower polyunsaturated fatty acid profile and lesser lipolysis than gilt sausages. Conclusion: Yeast inoculation with D. hansenii and long ripening time were appropriate strategies to limit the perception of boar taint in dry fermented sausages.
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Introduction: Debaryomyces (D) hansenii is a yeast widely used in meat fermentations as starter for the purpose of improving the aromatic quality of the final product. However, it has not been the subject of an extensive study regarding phenotypic characteristics important for starter selection such as the capacity to grow at abiotic stress conditions occurring during fermentation, the ability to generate desirable aromas and the absence of virulence traits in yeasts. Aims: The aim of this study was to screen 60 strains of Debaryomyces (D.) hansenii isolated from assorted foods for their potential application as starters in dry-cured fermented sausages manufacture. Methods: The abiotic stress factors tested were low aw and pH and high concentration of salt, acetic acid and lactic acid. The phenotypic virulence traits explored were growth at 37ºC, pseudohyphal and biofilm generation, invasiveness and enzymatic activities present in virulent yeasts. The generation of desirable meat aromas was tested in models containing aroma precursors applying an olfactory analysis. A quantitative profiling of stress tolerance was used to test the potential performance of selected strains in meat fermentations. Results: The results demonstrated that most strains displayed no virulence trait or were only positive for biofilm production. Moreover, the strains showed large heterogeneity regarding their tolerance to abiotic stress factors, although most of them could grow at intermediate to high levels of the traits. The sensory analysis was the criteria determining the selection of starter strains. Conclusions: The evaluation of the phenotypic traits demonstrates that D. hansenii is a safe yeast, it is able to tolerate the stress in meat fermentation and it is able to generate desirable aromas. Significance and impact of the study: The results of this study confirm the adequacy of selected D. hansenii strains to be applied as starters in meat products.
Article
Dry cured loins containing nitrogen (proline and ornithine) and sulfur (thiamine) compounds as precursors of aroma compounds at two concentration levels were manufactured. The effect of precursor addition on the microbiology and chemical parameters of loins was studied together with the aroma study performed by olfactometry and Free Choice Profile sensory analyses. Addition of precursors did not affect the microbial and chemical parameters, while aroma was affected when precursors were added at the highest level. The dry loin aroma profile was mainly composed by compounds 3-methylbutanal, methional, ethyl 3-methylbutanoate, 3-methylbutanoic acid, 1-octen-3-ol, 2-acetyl-1-pyrroline and 2-acetylpyrrole that contribute to musty, cooked potatoes, fruity, cheesy, mushroom, roasted and meaty odor notes. Proline and ornithine supplementation modified the loins aroma profile producing toasted odors, while the effect of thiamine supplementation on the aroma was revealed by the presence of sulfur derived compounds (methional and 2-methyl-3-(methylthio)furan) that contribute to the “cured meat odor”.
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The microbial population in koumiss, a traditional Mongolian fermented beverage, plays a vital role in its nutritional value, beneficial functions, and flavour. We used the Illumina MiSeq platform to investigate the successive bacterial communities produced during koumiss fermentation; dynamic changes in chemical composition of koumiss were also analysed. The correlation between bacterial species and major metabolites was then evaluated. The dominant bacterial species identified during the process of koumiss fermentation were Lactobacillus helveticus, Streptococcus parauberis (phylum Firmicutes), and Acetobacter pasteurianus (phylum Proteobacteria). Lactose content decreased during fermentation, whereas lactic acid, acetic acid, and butyric acid content increased, resulting in decreased pH. The changes in lactose, lactic acid, butyric acid, and pH were mainly correlated with the presence of the bacterial genera Acetobacter, Leuconostoc, Pediococcus, and Bacteroides. Information from these results could advance our understanding of koumiss fermentation, and also help improve the safety, flavour, and therapeutic applications of koumiss.
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The ability of Debaryomyces (D.) hansenii to produce volatile sulfur compounds from sulfur amino acids and the metabolic pathway involved has been studied in seven strains from different food origins. Our results proved that L-methionine is the main precursor for sulfur compounds generation. Crucial differences in the sulfur compound profile and amino acid consumption among D. hansenii strains isolated from different food sources were observed. Strains isolated from dry pork sausages displayed the most complex sulfur compound profiles. Sulfur compounds production, such as methional, could result from chemical reactions or yeast metabolism, while, according to this study, thioester methyl thioacetate appeared to be generated by yeast metabolism. No relationship between sulfur compounds production by D. hansenii strains and the expression of genes involved in sulfur amino acids metabolism was found, except for the ATF2 gene in L1 strain for production of methyl thioacetate. Our results suggest a complex scenario during sulfur compounds production by D. hansenii.
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The short term micro-flowing purification system (STMFPS) has been shown to improve the flesh quality of freshwater fish. However, few studies have focused on the involved underlying mechanisms. This study explored the effect of STMFPS on the flesh quality of market-size freshwater fish based on the combination of metabolomics and transcriptomics methods. The UPLC-QTOF/MS based metabolomics method was utilized to screen metabolites and predict the possible major metabolic pathways during different STMFPS treatment periods (0 d, 1 d, 5 d and 9 d). Furthermore, the transcriptomic data demonstrated that the differentially expressed genes detected in crucian carp muscle were 2915,7852 and 7183 after 1 d, 5 d and 9 d STMFPS treatment. Results showed that the TCA cycle, ornithine cycle, purine metabolism and amino acid catabolism play important roles in improving the flesh quality of crucian carp. This study may help to understand the mechanism of improving the flesh quality of aquatic products using STMFPS.
Chapter
Meat flavor is affected by the major precursors, proteins, and lipids. In this chapter, the main reactions involved in the development of cooked meat aroma are fully described: lipid degradation, Maillard reactions, Strecker degradation, thiamine degradation, and carbohydrate degradation. In addition, the different isolation and identification techniques used for flavor characterization of the volatile compounds present in meat are described together with techniques used for evaluation of potent odorants such as odor activity value and olfactometry analysis. The aroma compounds in cooked meat from different animal species have been summarized together with those pre- and postslaughter factors affecting it. The antemortem factors are age, breed, sex, feeding practices, fat level, fat profile, and composition while postmortem factors are aging, cooking, storage after cooking, and the development of off-flavors due to irradiation and storage. Finally, the development of meat product flavor through wet and dry curing is explained, and the main aroma compounds are defined.
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Flavour comprises mainly of taste and aroma and is involved in consumers’ meat-buying behavior and preferences. Chicken meat flavour is supposed to be affected by a number of ante- and post-mortem factors, including breed, diet, post-mortem ageing, method of cooking, etc. Additionally, chicken meat is more susceptible to quality deterioration mainly due to lipid oxidation with resulting off-flavours. Therefore, the intent of this paper is to highlight the mechanisms and chemical compounds responsible for chicken meat flavour and off-flavour development to help producers in producing the most flavourful and consistent product possible. Chicken meat flavour is thermally derived and the Maillard reaction, thermal degradation of lipids, and interaction between these 2 reactions are mainly responsible for the generation of flavour and aroma compounds. The reaction of cysteine and sugar can lead to characteristic meat flavour specially for chicken and pork. Volatile compounds including 2-methyl-3-furanthiol, 2-furfurylthiol, methionol, 2,4,5-trimethyl-thiazole, nonanol, 2-trans-nonenal, and other compounds have been identified as important for the flavour of chicken. However 2-methyl-3-furanthiol is considered as the most vital chemical compound for chicken flavour development. In addition, a large number of heterocyclic compounds are formed when higher temperature and low moisture conditions are used during certain cooking methods of chicken meat such as roasting, grilling, frying or pressure cooking compared to boiled chicken meat. Major volatile compounds responsible for fried chicken are 3,5-dimethyl-1,2,4-trithiolanes, 2,4,6-trimethylperhydro-1,3,5-dithiazines, 3,5-diisobutyl-1,2,4-trithiolane, 3-methyl-5-butyl-1,2,4-trithiolane, 3-methyl-5-pentyl-1,2,4-trithiolane, 2,4-decadienal and trans-4,5-epoxy-trans-2-decenal. Alkylpyrazines were reported in the flavours of fried chicken and roasted chicken but not in chicken broth. The main reason for flavour deterioration and formation of undesirable “warmed over flavour” in chicken meat products are supposed to be the lack of -tocopherol in chicken meat.
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This work is focused on the determination of compounds of nutritional interest that are naturally present in pork meat and how they are affected during the processing of dry-cured ham. Such compounds are creatine, creatinine, coenzyme Q(10), glutathione, carnosine, anserine, carnitine, taurine, cystine, cysteine and the essential amino acids. Their antioxidant and antyhipertensive functions were evaluated. Of all the assayed substances, only glutathione decreased totally during processing. Carnosine, creatinine, anserine and glutathione showed antioxidant, while cysteine, glutathione and carnosine showed antyhipertensive activity. So, dry-cured ham constitutes an excellent source of essential amino acids (all essential amino acids exhibited a large increase during processing) and other nutritionally interesting compounds such as cystine, cysteine, carnosine, anserine, taurine, carnitine and coenzyme Q(10).
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The importance of bacterial and meat enzymes in lipolysis and proteolysis was evaluated during dry sausage ripening. The data suggest that lipolysis is to a great extent brought about by muscle and fat tissue. Polyunsaturated fatty acids are liberated from the polar lipid fraction and their specific liberation is higher than for monounsaturated and saturated fatty acids. Lipolysis seemed to be more pronounced in sausages with pork than with beef. Initial protein degradation seemed to be originating from cathepsin D like muscle enzymes. In a later stage, bacterial enzymes become more important in further degradation of the protein fragments formed.
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Four types of Fermented sausages were prepared: two using Northern technology (Norway and Belgium) and two using Mediterranean technology (Belgium and Italy). Mediterranean sausages showed higher pH values and highest residual amounts of myosin and actin. Free fatty acid concentrations reflected the nature of the raw material, rather than the ripening period. Italian sausages contained the highest amounts of hexanal. Norwegian sausages contained the highest amounts of both free fatty acids and free amino acids. Putrescine concentration could be related to initial contamination of raw materials. Mediterranean sausages were characterised by a "pop corn" odour, identified as 2-acetyl-1-pyrroline. Proteolytic activity of pork Triceps brachii was found to be related to animal sex. Staphylococci and lactic acid bacteria were investigated. Leucine metabolism involving aldehyde production was found to be strain specific and very sensitive to pH and the presence of nitrite. Bacteria showed anti-oxidant activity, enhanced by the presence of manganese. Bacteriocin production by L. casei CTC 494 was studied and results incorporated into a mathematical model. (C) 2000 Elsevier Science Ltd. All rights reserved.
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Lipid oxidation, non-enzymatic browning development and volatile compounds generation were studied in sterile meat-model systems containing selected amino acids and/or liposomes during 35 days at 25 degrees C under pro-oxidative conditions, in order to simulate the ripening conditions of dry-cured meat products. Liposomes were prepared with polar lipids (PL) from Longissimus dorsi muscle of outdoors pigs fed on grass and acorns (M) or indoors ones fed on concentrates (C). Thiobarbituric acid reactive substances (TBA-RS) in systems containing both amino acids and liposomes were higher than in those containing only liposomes. The higher susceptibility to lipid oxidation of liposomes from C animal was reflected in higher TBA-RS throughout the experiment. All model systems containing liposomes and/or amino acids showed non-enzymatic browning development, as measured by the yellowness index. Major volatile compounds were fatty acid oxidation products. Strecker-derived volatile compounds were predominantly detected in model systems containing both amino acids and liposomes. The chromatographic areas of Strecker-derived volatiles increased over time whereas those of lipid-derived volatiles decreased. The occurrence of lipid oxidation, non-enzymatic browning and Strecker-type degradation of amino acids were shown in sterile meat-model systems at low temperatures.
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The key aroma components and the lipolysis in a dry cured sausage 'Sobrassada of Mallorca from black pig' were studied. Sobrassada was characterized by a fatty acid profile with a high content of monounsaturated fatty acids and by the generation during the curing process of polyunsaturated free fatty acids that were oxidized to generate flavor compounds. Eighty-four different volatile compounds were identified and three of them were for the first time detected in dry sausages (methyl nonanoate, 1-methyl-1H-pyrrole and 2-acetyl pyrrole). Thirty-five different aroma active zones were found. The aroma of sobrassada was not only due to compounds already detected as essential contributors in dry sausages (3-methyl butanoic acid, ethyl 3-methyl butanoate, 2, 3-butanedione and acetic acid) but also to other compounds such as ethyl octanoate, furfural, benzaldehyde, (Z)-2-nonenal, 4-methyl-phenol, delta-hexalactone, heptanoic acid, 2-pentylfuran and 2-acetyl-pyrrole which gave specific aroma notes.
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Dry fermented sausages with different fat contents were produced (10%, 20% and 30%). The effect of fat content and ripening time on sensory characteristics, lipolysis, lipid oxidation and volatile compounds generation was studied. Also, the key aroma components were identified using gas chromatography (GC) and olfactometry. High fat sausages showed the highest lipolysis and lipid oxidation, determined by free fatty acid content and thiobarbituric acid reactive substances (TBARS), respectively. A total of 95 volatile compounds were identified using SPME, GC and mass spectrometry (MS). Fat reduction decreased the generation of lipid derived volatile compounds during processing while those generated from bacterial metabolism increased, although only at the first stages of processing. The consumers preference in aroma and overall quality of high and medium fat sausages was related to the aroma compounds hexanal, 2-nonenal, 2,4-nonadienal, ethyl butanoate and 1-octen-3-ol which contributed green, medicinal, tallowy, fruity and mushroom notes.
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Production of volatile sulphur compounds (VSC) was assessed in culture media supplemented with L-methionine or L-methionine/L-cysteine mixtures, using five cheese-ripening yeasts: Debaryomyces hansenii DH47(8), Kluyveromyces lactis KL640, Geotrichum candidum GC77, Yarrowia lipolytica YL200 and Saccharomyces cerevisiae SC45(3). All five yeasts produced VSC with L-methionine or L-methionine/L-cysteine, but different VSC profiles were found. GC77 and YL200 produced dimethyldisulphide and trace levels of dimethyltrisulphide while DH47(8), KL640 and SC45(3) produced mainly methionol and low levels of methional. S-methylthioacetate was produced by all the yeasts but at different concentrations. DH47(8), KL640 and SC45(3) also produced other minor VSC including 3-methylthiopropyl acetate, ethyl-3-methylthiopropanoate, a thiophenone, and an oxathiane. However, VSC production diminished in a strain-dependent behaviour when L-cysteine was supplemented, even at a low concentration (0.2 g l(-1)). This effect was due mainly to a significant decrease in L-methionine consumption in all the yeasts except YL200. Hydrogen sulphide produced by L-cysteine catabolism did not seem to contribute to VSC generation at the acid pH of yeast cultures. The significance of such results in the cheese-ripening context is discussed.
Book
Since publication of the first edition in 1971, Fenaroli's Handbook of Flavor Ingredients has remained the standard reference for flavor ingredients throughout the world. Each subsequent edition has listed more flavor ingredients and allied substances, including those conferred food additive status, substances generally recognized as safe (GRAS) by qualified scientists (including the Flavor and Extract Manufacturers' Association Expert Panel) and those substances having undergone GRAS Notification with the Food and Drug Administration (FDA). New in the Sixth Edition 200+ newly approved flavor ingredients Ingredient's safety standing with the Flavor and Extract Manufacturers' Association and/or the FDA Extensive and expanded information on aroma and taste thresholds Updated regulatory information on each flavor ingredient New discussion on botanical substances that serve as flavoring ingredients The fourth and fifth editions added more than 300 new entries and represented a total reorganization and updating of the text, consistent with new data and regulations. This, the sixth edition, is likewise expanded with over 200 new entries, including many botanicals and other natural substances. The addition of botanicals is a response to an expanded readership with an interest in dietary supplements, in which a number of flavoring botanicals serve a dual role.
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On the basis of the results of labeling experiments, endogenous valine, glycine, and methionine are considered to be the precursors of 2-methoxy-3-isopropylpyrazine (MIPP) produced by Pseudomonas perolens. It is postulated that the feeding of [2-13C]pyruvate results in the labeling of C-2 and C-3 of valine and C-2 of glycine, which are subsequently incorporated into MIPP. The feeding of [3-13C]-pyruvate results in the labeling of the two methyl groups of valine, C-1 and C-2 of glycine, and the methyl group of methionine. 13C NMR spectra of the MIPP produced by P. perolens in these feeding studies were consistent with the proposed biosynthetic route to MIPP and known metabolic pathways. Methyllabeled methionine arises from [2-13C]glyoxylate formed from [3-13C]pyruvate via the Krebs cycle and glyoxylate shunt.
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The volatiles of various meat model systems containing thiamin, cysteine, cystine, and various carbohydrates were isolated by simultaneous steam distillation-extraction. The extracts were pre-separated by medium-pressure liquid chromatography on silica gel using a pentane/diethyl ether gradient. The resulting fractions were analyzed by high-resolution gas chromatography and coupled gas chromatography-mass spectrometry (GC/MS). Identifications were focused on sulfur-containing constituents. Individual components were isolated by preparative capillary GC and characterized by MS, IR, and 1H NMR spectroscopies. Various sulfur-containing compounds were identified for the first time in meat model systems or even in the context of flavor chemistry. In most cases, their structures were confirmed by synthesis. Formation pathways, sensory properties, and spectroscopic data of various compounds are described.
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A new general synthetic route towards three key Maillard flavour compounds, namely 2-acetyl-1-pyrroline, 6-acetyl-1,2,3,4-tetrahydropyridine and 5-acetyl-2,3-dihydro-4H-1,4-thiazine, was developed. The key step in the process is the methylenation reaction of azaheterocyclic carboxylic esters by means of dimethyltitanocene, giving rise to intermediate vinyl ethers which can be considered as excellent and stable precursors for the title compounds, as a simple acidic treatment of these precursors suffices to release the characteristic Maillard flavours.
Article
Background The use of different extraction techniques; solid phase microextraction (SPME) and solvent assisted flavour evaporation (SAFE) technique can deliver different aroma profile and it is essential to determine which is most suitable to extract the aroma compounds from dry fermented sausages.ResultsForty five aroma active compounds were detected by SPME and SAFE being 11 of them reported for the first time as aroma compounds in dry fermented sausages; ethyl 3-hydroxy butanoate, trimethyl pyrazine, D-pantolactone, isobutyl hexanoate, ethyl benzoate, α-terpineol, ethyl 3-pyridinecarboxylate, benzothiazole, 2,3-dihydrothiophene, methyl eugenol, γ-nonalactone. The aroma concentration and odour activity values (OAVs) were calculated. Flavour reconstitution analyses were performed using 20 odorants with OAVs above 1 obtained from the SAFE and SPME extracts to prepare the aroma model.ConclusionSPME and SAFE techniques were complementary and necessary to reproduce the overall dry fermented sausage aroma. The final aroma model included the odorants from both extraction techniques (SPME and SAFE) but it was necessary to incorporate the compounds 2,4-decadienal (E,E), benzothiazole, methyl eugenol, α-terpineol, and eugenol to the final aroma model to evoked the fresh sausage aroma although a lowest cured meat aroma note was perceived.
Article
The ability of seven Debaryomyces hansenii strains to generate aroma compounds in a fermented sausage model system was evaluated. The presence of the yeast, in the inoculated models, was confirmed by PCR amplification of M13 minisatellite. Volatile compounds production was analysed using Solid Phase Micro-Extraction and gas chromatography/mass spectrometry. Forty volatile compounds were detected, quantified and their odour activity values (OAVs) calculated. All volatile compounds increased during time in the inoculated models although significant differences were found amongst them. Ester and sulphur production was strongly dependent on the strain inoculated. D. hansenii P2 and M6 strains were the highest producers of sulphur compounds where dimethyl disulphide and dimethyl trisulfide were the most prominent aroma components identified by their OAVs whereas, M4 showed the highest OAVs for ester compounds followed by the P2 strain. The meat model system has been useful to show the real ability of yeast strains to produce aroma compounds.
Article
The neutral volatile fraction of a French dry fermented sausage (salami) was isolated using either variants of molecular distillation (MD) dynamic headspace enrichment, high vacuum distillation vacuum steam distillation, or combined gel permeation chromatography/MD. The best ar oma yields were obtained with the MD of the solvent extract and gel permeation chromatography/MD. A total of 126 volatile constituents was isolated using MD from four air dried, mould ripened salami manufactured in France Italy, Spain, and Germany. Gas Chromatography-Olfactometry (GC-O) of the aroma concentrates showed that most of the sensory active compounds occurred in all of the sausages, but often in very different concentrations. The highest odour activities (dilution factor 1:10,000) were found for diallyl disulphide and eugenol, followed by 3-methylbutanoic acid acetic acid, linalool, methylallyl sulphide, and diallyl sulphide (1:1,000) Sensory descriptions of the salami were in good agreement with the quantity of the key odour components present in the different salami products. (C) 1998 Academic Press.
Article
The effect of small pH changes on volatile compounds produced in the Maillard reaction was investigated using aqueous model systems. The reaction mixtures consisted of four amino acids, glycine, lysine, cysteine and methionine, heated individually with ribose at five pH values between 4.5 and 6.5. The colour, the overall aroma and the nature of the volatile compounds were all influenced by pH. At low pHs, 2-furfural was a major product of all the model systems, but its concentration decreased as the pH was raised. Nitrogen-containing compounds, such as pyrazines were detected at higher pHs, with the lysine model system producing the largest quantities of nitrogen-containing heterocyclic compounds. The major products of the methionine systems were dimethyl disulphide and 3-(methylthio)propanal and, as the pH increased, the latter compound showed a small decrease in concentration, while an increase in the disulphide was observed. The cysteine model system led to a large number of sulphur-containing compounds, including 2-methyl-3-furanthiol, a compound with a strong meaty aroma, whose formation was greatly favoured by lower pH.
Article
For economical reasons and to accommodate current market trends, cheese manufacturers and product developers are increasingly interested in controlling cheese flavor formation and developing new flavors. Due to their low detection threshold and diversity, volatile sulfur compounds (VSCs) are of prime importance in the overall flavor of cheese and make a significant contribution to their typical flavors. Thus, the control of VSCs formation offers considerable potential for industrial applications. This paper gives an overview of the main VSCs found in cheese, along with the major pathways and key enzymes leading to the formation of methanethiol from methionine, which is subsequently converted into other sulfur-bearing compounds. As these compounds arise primarily from methionine, the metabolism of this amino acid and its regulation is presented. Attention is focused in the enzymatic potential of lactic acid bacteria (LAB) that are widely used as starter and adjunct cultures in cheese-making. In view of industrial applications, different strategies such as the enhancement of the abilities of LAB to produce high amounts and diversity of VSCs are highlighted as the principal future research trend.
Article
Slow fermented sausages with different salt content were manufactured: control (2.7% NaCl, S), 16% salt reduced (2.26% NaCl, RS) and 16% replaced by KCl (2.26% NaCl and 0.43% KCl, RSK). The effect of salt reduction on microbiology and chemical parameters, sensory characteristics, texture and volatile compounds was studied. The aroma compounds were identified by GC-MS and olfactometry analyses. Small salt reduction (16%) (RS) affected sausage quality producing a reduction in the acceptance of aroma, taste, juiciness and overall quality. The substitution by KCl (RSK) produced the same acceptability by consumers as for high salt (S) treatment except for the aroma that was not improved by KCl addition. The aroma was affected due to the reduction in sulfur and acids and the increase of aldehyde compounds. Aroma compounds that characterized the high salt treatment (S) were dimethyl trisulfide, 3-methyl thiophene, 2,3-butanedione, 2-nonanone and acetic acid.
Article
Lactic acid bacteria (LAB) play a central role in several food fermentations, producing lactic acid besides other metabolic actions. Popular fermented foods that rely on the use of LAB include fermented meats, sourdoughs, and fermented dairy products. During fermentation, LAB are frequently accompanied by other microorganisms, such as coagulase-negative staphylococci (CNS), yeasts, and filamentous fungi.Whereas fermentationwas originally a spontaneous and empiric process, most industrial processes make now use of starter cultures to speed up the fermentation process and standardise the end products and to reduce the risks on misfermentation. A drawback of using commercial starter cultures is their suboptimal selection, which is often solely based on mere technological features. Currently, functional starter cultures are being developed to further optimise the process and to yield additional nutritional, safety, and quality benefits. Specific metabolic properties are being sought for, with a focus on novel, interesting molecules that may, for instance, inhibit undesirable microorganisms,
Article
The contributions of N-15-labeled glycine and tested amino acids (glutamine, glutamic acid, asparagine, aspartic acid, lysine, arginine, phenylalanine, and isoleucine) to pyridine, pyrrole, and oxazole formation were investigated. Ten pyridines, nine pyrroles, two oxazoles, three amines, and one benzonitrile were identified in the present study. The quantities of pyridines, pyrroles, and oxazoles in the reaction mixture of glycine and aspartic acid were the highest. Aspartic acid, lysine, and asparagine had the highest contribution in pyridine, pyrrole, and oxazole formation, respectively. In the presence of glycine, glutamic acid showed the least contribution, whereas asparagine had the highest contribution to the formation of all nitrogen-containing compounds among the tested amino acids. While lysine was able to increase the reactivity of glycine, arginine inhibited the capability of glycine to produce nitrogen-containing volatile compounds.
Article
Different deproteinization techniques have been tested for free amino acids analysis in fresh pork muscle and dry-cured ham. These techniques include chemical precipitants (trichloroacetic acid, perchloric acid, sulfosalicylic acid, phosphotungstic acid, picric acid, and acetonitrile) and ultrafiltration through 10 000 and 1000 M(r) cutoff membranes. Phenyl isothiocyanate amino acids were analyzed by reverse-phase HPLC. Good amino acid recoveries (more than 90%) from a standard amino acid solution were obtained except when sulfosalicylic acid, phosphotungstic acid, and ultrafiltration through 1000 M(r) cutoff membrane were used, which gave important losses of some amino acids. Similar results were obtained for both meat and dry-cured ham samples. However, an interfering peak that coelutes to arginine was observed. Only phosphotungstic acid completely removed that peak, but it gave important losses in dibasic amino acids.
Article
Following long dry-curing periods, Spanish “Serrano” ham develops a specific “dry-cured ham” flavor. To determine the effects of length of curing on flavor generation, replicate hams were processed for 7 or 12 mo prior to amino acid, peptide, and flavor evaluation by reverse phase HPLC, capillary zone electrophoresis, and sensory analysis, respectively. Generation of dry-cured and pork flavors correlated with the accumulation of amino acids. The relation of these components with sensory descriptors was examined by factor analysis. Results indicated that combinations and proportions of taste-active components produced the specific dry-cured flavor characteristic rather than an accumulation of any single flavor component.
Article
 A compact and versatile distillation unit was developed for the fast and careful isolation of volatiles from complex food matrices. In connection with a high vacuum pump (5×10–3 Pa), the new technique, designated solvent assisted flavour evaporation (SAFE), allows the isolation of volatiles from either solvent extracts, aqueous foods, such as milk or beer, aqueous food suspensions, such as fruit pulps, or even matrices with a high oil content. Application of SAFE to model solutions of selected aroma compounds resulted in higher yields from both solvent extracts or fatty matrices (50% fat) compared to previously used techniques, such as high vacuum transfer. Direct distillation of aqueous fruit pulps in combination with a stable isotope dilution analysis enabled the fast quantification (60 min including MS analysis) of compounds such as the very polar and unstable 4-hydroxy-2,5-dimethyl-3(2H)-furanone in strawberries (3.2 mg/kg) and tomatoes (340 μg/kg). Furthermore, the direct distillation of aqueous foods, such as beer or orange juice, gave flavourful aqueous distillates free from non-volatile matrix compounds.
Article
The volatile compounds formed during autoxidation of linoleic acid and methyl linoleate at 22–24 °C were analysed by high resolution gas chromatography and eluate sniffing. The application of this technique to stepwise diluted extracts of the volatile compounds allowed the determination of a new parameter, theD-value, which reveals the most intense flavour compounds of an extract. Hexanal, 2(Z)-octenal and 2(E)-nonenal exhibited the highestD-values in both lipids. 1-Octen-3-ol followed in the case of linoleic acid and 1-octen-3-one in that of methyl linoleate. The grading of the flavour compounds was dependent on the autoxidation time. 2(E)-Nonenal was the most potent aroma compound up to 24 h of linoleic acid autoxidation. After 48 h aldehyde and hexanal and after 72 h hexanal and 2(Z)-octenal possessed the highestD-values. TheD-value can also be used for the approximation of odour threshold values as demonstrated for 2(Z)-octenal, 2(E)-nonenal and 1-octen-3-ol.
Article
Recently we established bakers' yeast as a potent source of precursors for the roast-smelling odorants 2-acetyl-1-pyrroline (ACPY) and 2-acetyltetrahydropyridine (ACTPY) in wheat bread crust. To reveal their role in the formation of both odorants, the concentrations of free amino acids occurring in baker's yeast were determined. The 11 amino acids present in concentrations above 60 mg/100 g dry yeast were separately reacted with 2-oxopropanal in model solutions and the amounts of ACPY and ACTPY formed, determined by a stable isotope dilution assay (SIDA). ACPY was formed from proline and ornithine, while ACPTY was exclusively liberated from proline. The remaining amino acids were ineffective. Further experiments revealed that the formation of ACPY from ornithine proceeds via 4-aminobutyraldehyde and 1-pyrroline as intermediates. The amount of free ornithine in yeast was more than three times the amount of free proline. Furthermore, additions of either proline or ornithine to wheat doughs enhanced the amounts of ACPY in the bread crust by a factor of two or four, respectively. The data led to the conclusion that ornithine is the most important precursor for the formation of ACPY during baking.
Article
The characteristic flavour of cooked meat derives from thermally induced reactions occurring during heating, principally the Maillard reaction and the degradation of lipid. Both types of reaction involve complex reaction pathways leading to a wide range of products, which account for the large number of volatile compounds found in cooked meat. Heterocyclic compounds, especially those containing sulfur, are important flavour compounds produced in the Maillard reaction providing savoury, meaty, roast and boiled flavours. Lipid degradation provides compounds which give fatty aromas to cooked meat and compounds which determine some of the aroma differences between meats from different species. Compounds formed during the Maillard reaction may also react with other components of meat, adding to the complexity of the profile of aroma compounds. For example, aldehydes and other carbonyls formed during lipid oxidation have been shown to react readily with Maillard intermediates. Such interactions give rise to additional aroma compounds, but they also modify the overall profile of compounds contributing to meat flavour. In particular, such interactions may control the formation of sulfur compounds, and other Maillard-derived volatiles, at levels which give the optimum cooked meat flavour characteristics.
Article
2,5-Dimethylpyrazine (2,5-DMP) and tetramethylpyrazine (TTMP) were produced using Bacillus subtilis IFO 3013 grown in solid substrate conditions using ground soybeans suspended in water. Optimization studies showed that the best way to produce the two above aroma compounds involved massive enrichment of the medium with l-threonine and acetoin. The amino acid allowed 2,5-DMP formation and was added at 40 g/l at the beginning of a process, while acetoin was the precursor of TTMP and had to be added at 60 g/l only after 2,5-DMP production was terminated. The optimal cultivation temperature was 40°C, pH had to be monitored at 7.5, and aeration rate had to be higher than 0.1 VVM with a volumetric oxygen tranfer coefficient kLa close to 180 h−1. These conditions allowed recovery of 2 g/l total pyrazines, that demonstrated the efficiency of this approach.
Article
Sausages, with added Staphylococcus xylosus, were fermented at different temperatures and with different added levels of salt, glucose, nitrite, nitrate and Pediococcus pentosaceus in accordance with a six factor fractional design. The volatile compounds from the sausages were collected by dynamic headspace sampling and quantified and identified by gas chromatography and gas chromatography-mass spectrometry. The effects of temperature and different ingredients on the levels of individual volatiles were tested using multiple linear regression and analysis of variance. The study showed that sausages fermented under modern production conditions (high temperature, addition of glucose, nitrite, Pediococcus pentosaceus) in contrast to 'old-fashioned' sausages (added nitrate and fermented at low temperature) are likely to contain higher amounts of volatile acids, but lower levels of ethyl esters, certain short chain aldehydes as well as lipid autoxidation products. Several nitriles, nitro-alkanes and one organic nitrate were identified for the first time in fermented sausages. Reaction mechanisms for those compounds and other classes of compounds are proposed and discussed in detail.
Article
Three sausage batches inoculated with normal inoculation level of Pediococcus pentosaceus (5×10(6) CFU/g) and with low, intermediate, and high inoculation levels of Staphylococcus carnosus (10(5), 5×10(6), 5×10(7) CFU/g, respectively) were produced. Cell counts and formation of volatiles were followed throughout a ripening period of three weeks. The staphylococci exhibited the fastest growth in sausages with a low inoculation level, whereas growth was only moderate in sausages with a high initial level. Analysis of volatiles showed that methyl-branched aldehydes and acids, phenylacetaldehyde, 2-methyl-1-butanol, dimethyldisulphide and dimethyltrisulphide were produced in higher amounts in sausages with a high inoculation level of S. carnosus, whereas a low inoculation level correlated with high amounts of diacetyl, ethanol and ethyl esters. The levels of most compounds increased over time, but the amount of diacetyl was negatively correlated to ripening time. A negative interaction effect between inoculation level and ripening time was observed for the amounts of methyl-branched aldehydes.
Article
Application of aroma extract dilution analysis on an extract/distillate prepared from a Hungarian-type salami and subsequent identification experiments led to the identification of 51 of 55 odor-active compounds detected in the flavor dilution (FD) factor range of 16-4096. Nineteen of these compounds are reported for the first time as aroma components of dry-fermented sausages, among them 3-hydroxy-4,5-dimethyl-2(5H)-furanone (sotolon), trans-4,5-epoxy-(E)-2-decenal, and bis(2-methyl-3-furyl) disulfide. The highest FD factors were found for 2-methoxyphenol (smoky, sweet), 2-methoxy-4-(2-propenyl)phenol (clove-like), 2-methoxy-4-(E)-(1-propenyl)phenol (clove-like), and acetic acid (pungent, sour). Forty-five aroma compounds were subsequently quantified using stable isotope dilution assays, and their odor activity values (OAVs; ratio of concentration to odor threshold) were calculated on the basis of odor thresholds in oil. The highest OAVs were calculated for acetic acid, acetaldehyde, 3-(methylthio)propanal, phenylacetaldehyde, 2-methoxyphenol, and 2-acetyl-1-pyrroline. A model mixture containing 33 odorants in the same concentrations as they occurred in the sausage was prepared in a matrix consisting of 44% sunflower oil and 56% aqueous phosphate buffer. A comparison of the overall aroma of this model mixture with the original showed a very high similarity, suggesting that the key aroma compounds were successfully identified.
Article
This work describe products of reactions between four alpha-dicarbonyl compounds (diacetyl, pentan-2,3-dione, glyoxal, and methylglyoxal) or two alpha-hydroxy ketones, (acetoine and acetol) and amino acids present in wines. The results shows the formation of odorous products or strong-smelling additives resulting from the Maillard and Strecker reaction in a primarily aqueous medium, at low temperature and low pH ( approximately pH 3.5) of the wine. GC/FID, GC/FPD, GC/NPD and GC/MS techniques were used. The olfactive characteristics of the products are described. In the presence of sulfur amino acids and in particular cysteine, many products were formed with a heterocycle production such as pyrazines and methylpyrazines, methylthiazoles, acetylthiazoles, acetylthiazolines, acetylthiazolidines, trimethyloxazole, and dimethylethyloxazoles. These various compounds present odors of sulfur, cornlike, pungent, nut, popcorn, roasted hazelnut, toasted, roasted, and ripe fruits. The chemical conditions of the model reactions are specified. The influence of temperature and pH on the reactions in the presence of cysteine were also studied.
Article
This paper compares the volatile constituents of model systems containing the important meat aroma precursors cysteine and ribose, with and without either methyl linoleate, an n-6 fatty acid, or methyl alpha-linolenate, an n-3 acid, both of which are present in meat. Many of the volatile compounds formed from the reaction between cysteine and ribose were not formed, or formed in lower amounts, when lipid was present. This may be due to the reaction between hydrogen sulfide, formed from the breakdown of cysteine, and lipid degradation products. In addition, cysteine and ribose modified lipid oxidation pathways, so that alcohols and alkylfurans were formed rather than saturated and unsaturated aldehydes. Several volatile compounds, which have been found at elevated levels in cooked meat from animals fed supplements high in n-3 acids, were formed when methyl alpha-linolenate reacted with cysteine and ribose. The possible effects of increasing the n-3 content of meat upon flavor formation during cooking are discussed.
Meat Fermentation Technology
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