Characterization of volatile compounds, physico-chemical and sensory characteristics of smoked dry-cured ham

Identification and quantification of flavor compounds in smoked tuna fish based on GC-Orbitrap volatolomics approach

Cold smoking enhances the appeal of fish products, offering consumers a smooth texture and a delicate smoky flavor. This study aims to explore variations in the volatile profile from different exposure times during cold smoking processing (light, moderate, and full-cure) in tune samples. An innovative untargeted analytical approach, headspace solid-phase microextraction combined with gas chromatography and a hybrid quadrupole-orbitrap mass analyzer, was employed to identify 86 volatiles associated with the cold smoking process. Most of these compounds, including phenols, furan derivates, aldehydes, cyclic ketones, and different aromatic species, were found to contribute to the smoke odor. The development of a QuEChERS-based extraction and clean-up method facilitated the quantification of 25 relevant smoky markers across all smoking degrees, revealing significant concentration differences after 15 h of smoking. This research sheds light on the dynamics of cold smoking impact and its on the flavor profile and safety quality of processed fish products.

Composite starch films as green adsorbents for removing benzo[a]pyrene from smoked sausages

Benzo[a]pyrene (BaP), which is emitted during the processing of smoked sausages, accumulates in sausages and poses a serious threat to human health. This study focused on the removal of BaP from sausages and accompanying particulate matter (PM) during the smoking of sausages by films formed by combining corn starch (CS) with K-carrageenan (KC)/sodium alginate (SA). Initially, the effects of different additions of KC and SA on the rheological analysis, thermogravimetric analysis (TGA) and film-forming properties of the composite films were investigated. The BaP reduction capacities of CS-KC and CS-SA composite films in sausage were 41.1%-47.0% and 54.2%-56.5%, respectively, because the three-dimensional mesh structure of the composite films provided a large number of adsorption sites. Finally, kinetic studies demonstrated that BaP control in composite films is mainly achieved by intraparticle diffusion. Therefore, due to its excellent recyclability and biodegradability, composite starch film has a promising application in smoked meat products.

Effect of Starter Culture and Temperature on the Flavor and Sensory Characteristics of Dry-Cured Ham

This study focused on understanding the effects of yeast and mold on the sensory properties of dry-cured ham aged at 20°C and 25°C. Debaryomyces hansenii isolated from Doenjang and fermented sausages, and Penicillium nalgiovense isolated from fermented sausages were utilized. The CIE a* tended to increase in all treatments as the aging period increased. At 6 weeks of aging, DFD25 showed a significantly higher CIE a* value than other treatments. The shear force tended to increase in all treatments as the aging period increased. At 6 weeks of aging, among the treatments aged at 25°C, DFD25 showed a low tendency to shear force. The PC1 of the electronic nose was 42.872%. At 25°C, the hexane content was higher and levels of ethanol, propan-2-one, 2,4,5-trimethylthiazole, and limonene were lower than that at 20°C. DFD25 showed significantly higher hexane content and significantly lower limonene content than other treatments. The PC1 of the electronic tongue was 84.529%. All treatments, except for the C starter, exhibited higher salt and lower sour levels at 25°C compared to 20°C when the same starter was used. The DFD25 showed the lowest sour taste and a higher tendency of umami than the other treatments. Sensory evaluation revealed that DFD25 had significantly higher scores for texture than C25, whereas no significant differences were observed in other aspects. Therefore, the used starters are considered suitable for aging at 25°C; among them, the DFD starter demonstrates superior qualities and enhanced commercial potential compared to the control.

Geographical region traceability of wild topmouth culter (Culter alburnus) from Xingkai Lake based on muscle quality and aroma profiles

The wild topmouth culter (Culter alburnus) from Xingkai Lake (XKL) is highly regarded for its delicious taste and unique flavor. In this study, based on muscle quality and aroma analysis, we first differentiated the XKL population from three wild populations in Heilongjiang Province and one artificially cultured population (from Xingkai Lake). Compared with the other populations, the XKL population has a significantly higher crude protein content, essential amino acid content, delicious amino acid content, and n-3/n-6 PUFA ratio. Additionally, it exhibits superior hardness, elasticity, chewiness, recoverability, and viscosity. E-nose detection analysis revealed that W1S, W2S, and W3S were the potential sensors contributing the most to the differences among the five populations. HS-SPME-GC-MS and multivariate regression analysis showed that 21 volatile flavor compounds were identified as key markers for geographical identification of the Xingkai Lake region. These findings will provide guidance for the geographical traceability and identification of the XKL population.

Lipid Peroxidation in Muscle Foods: Impact on Quality, Safety and Human Health

The issue of lipid changes in muscle foods under the action of atmospheric oxygen has captured the attention of researchers for over a century. Lipid oxidative processes initiate during the slaughtering of animals and persist throughout subsequent technological processing and storage of the finished product. The oxidation of lipids in muscle foods is a phenomenon extensively deliberated in the scientific community, acknowledged as one of the pivotal factors affecting their quality, safety, and human health. This review delves into the nature of lipid oxidation in muscle foods, highlighting mechanisms of free radical initiation and the propagation of oxidative processes. Special attention is given to the natural antioxidant protective system and dietary factors influencing the stability of muscle lipids. The review traces mechanisms inhibiting oxidative processes, exploring how changes in lipid oxidative substrates, prooxidant activity, and the antioxidant protective system play a role. A critical review of the oxidative stability and safety of meat products is provided. The impact of oxidative processes on the quality of muscle foods, including flavour, aroma, taste, colour, and texture, is scrutinised. Additionally, the review monitors the effect of oxidised muscle foods on human health, particularly in relation to the autooxidation of cholesterol. Associations with coronary cardiovascular disease, brain stroke, and carcinogenesis linked to oxidative stress, and various infections are discussed. Further studies are also needed to formulate appropriate technological solutions to reduce the risk of chemical hazards caused by the initiation and development of lipid peroxidation processes in muscle foods.

Insight into the Relationship between the Causes of Off-Odour and Microorganism Communities in Xuanwei Ham

To expound on the correlation between the microorganism communities and the formation of off-odour in Xuanwei ham, the microorganism communities and volatile compounds were investigated in the biceps femoris (BF) and semimembranosus (SM) of Xuanwei ham with different quality grades (normal ham and spoiled ham). The single molecule real-time sequencing showed that differential bacteria and fungi were more varied in normal hams than in spoiled hams. Headspace solid-phase microextraction-gas chromatography (HS-SPME-GC-MS) results indicated that aldehydes and alcohols were significantly higher in spoiled hams than those in normal hams (p < 0.05). The off-odour of spoiled hams was dominated by ichthyic, malodourous, sweaty, putrid, sour, and unpleasant odours produced by compounds such as trimethylamine (SM: 13.05 μg/kg), hexanal (BF: 206.46 μg/kg), octanal (BF: 59.52 μg/kg), methanethiol (SM: 12.85 μg/kg), and valeric acid (BF: 15.08 μg/kg), which are positively correlated with Bacillus cereus, Bacillus subtilis, Bacillus licheniformis, Pseudomonas sp., Aspergillus ruber, and Moraxella osloensis. Furthermore, the physicochemical property and quality characteristics results showed that high moisture (BF: 56.32 g/100 g), pH (BF: 6.63), thiobarbituric acid reactive substances (TBARS) (SM: 1.98 MDA/kg), and low NaCl content (SM: 6.31%) were also responsible for the spoilage of hams with off-odour. This study provided a deep insight into the off-odour of Xuanwei ham from the perspective of microorganism communities and a theoretical basis for improving the flavour and overall quality of Xuanwei hams.

Effects of Animal Diet and Processing Methods on the Quality Traits of Dry-Cured Ham Produced from Turopolje Pigs

The Turopolje pig (TP) is a local Croatian pig breed that almost became extinct in the second half of the 20th century. Today, the TP is still endangered, and a new conservation strategy based on products with higher added value is needed to preserve the breed. There is little information on the quality of TP meat products such as smoked and dry-cured ham, including the impact of natural feeds or processing innovations such as smoke reduction. This study, therefore, investigated the effects of the animal's diet (either conventionally fed or acorn-supplemented) and the processing method (standard or lightly smoked) on the quality traits of dry-cured TP ham. Twenty hams, evenly distributed among the treatments, were processed for 15 months and then analysed for physicochemical and textural traits, volatiles and sensory profile. The hams from acorn-supplemented pigs lost less weight during processing (p ≤ 0.05). Otherwise, the diet had no significant effect on most examined ham traits. The exceptions were protein content and the texture parameter hardness, which decreased (p ≤ 0.05), and the degree of proteolysis and colour parameters, which increased (p ≤ 0.05) as a result of acorn supplementation. However, these effects were generally small and varied between the inner (m. biceps femoris) and outer (m. semimembranosus) muscles. Furthermore, acorn supplementation was associated with less typical ham odour and lower sensory scores for sweetness and colour uniformity (p ≤ 0.05). The smoke reduction had no effect on the physicochemical and colour properties but resulted in a significant reduction (p ≤ 0.05) in the volatile phenolic compounds and an improved texture to the hams. This was reflected both in reduced (p ≤ 0.05) hardness, identified in the instrumental analysis, and in an increased (p ≤ 0.05) softness, solubility and moistness, identified in the sensory evaluation. To summarize, the quality of the TP ham under the conditions studied was only slightly affected by acorn supplementation, whereas reduced smoking had a more significant effect, which was mainly reflected in an improved texture.

Comparing Physicochemical Properties, Fatty Acid Profiles, Amino Acid Composition, and Volatile Compounds in Dry-Cured Loin: The Impact of Different Levels of Proteolysis and Lipid Oxidation

The aim of this study is to compare the quality characteristics of dry-cured loins with different levels of proteolysis and lipid oxidation and to investigate the relationship between these factors on quality characteristics. The dry-cured loins were divided into four groups [proteolytic index (PI) and 2-thiobarbituric acid reactive substances (TBARS) of high levels (HH), PI of high level and TBARS of low level (HL), PI of low level and TBARS of high level (LH), and PI and TBARS of low levels (LL)] based on the proteolysis index and TBARS. Moisture, protein, and fat content were all significantly influenced by proteolysis and lipid oxidation (p<0.05). The total fatty acid content in the high proteolysis groups (HH and HL) was significantly lower than that in the low proteolysis groups (LH and LL; p<0.05). For total free amino acid content, HH was the highest, and LL was the lowest (p<0.05). On the other hand, there was no significant difference between HL and LH (p>0.05). In the amount of total volatile compounds, there was no significant difference between HH and HL (p>0.05), but LH and LL significantly differed (p<0.05). In conclusion, proteolysis and lipid oxidation can influence the quality characteristics of dry-cured loin. Additionally, proteolysis might be as influential in generating volatile compounds as lipid oxidation.

Characterization of key aroma compounds in Chinese smoked duck by SAFE-GC-O-MS and aroma-recombination experiments

Smoked duck is a popular meat product in China. The aroma profile and key aroma compounds in smoked ducks were elucidated using solvent-assisted flavor evaporation-gas chromatography-olfactometry-mass spectrometry (SAFE-GC-O-MS), odor activity values (OAVs), aroma recombination and omission experiments, and sensory evaluation. The results indicated that the predominant aroma profiles of rice-, tea oil- and sugarcane-smoked ducks all contained strong smoky, roasty, fatty, meaty, and grassy aromas. A total of 31 aroma compounds were identified as important odorants by OAVs, including 8 aldehydes, 6 pyrazines, 5 phenols, and 2 sulfur compounds. The aroma recombination and omission experiments confirmed that 13 odorants were key aroma compounds in smoked ducks. Of these odorants, 2-methoxyphenol, 4-methylphenol, 5-ethyl-2,3-dimethylpyrazine, methional, 2-methyl-3-furanthiol, (E, E)-2,4-decadienal, 1-octen-3-ol, and anethole significantly contributed to the aroma profile of smoked duck flavor (p < 0.01).

Regional distribution and diversity of Aspergillus and Penicillium species on Croatian traditional meat products

Various factors, such as weather and production practices (e.g., environmental hygiene, process duration, raw material quality, ripening temperature, and relative humidity), in combination with the intrinsic product properties (e.g., pH, aw, salt content), significantly affect the growth of surface moulds. The aim of this study was to isolate and identify surface moulds retrieved from traditional meat products (TMPs) and correlate these data to the production region and production technology. The surface of 250 TMPs (dry-fermented sausages, n = 108; dry-cured meat products, n = 142) from five Croatian regions were sampled during a two-year period. Dry-fermented sausages had a significantly higher pH and a lower salt concentration when compared to dry-cured meat products. In total, 528 isolates were obtained, comprising 20 Penicillium and 17 Aspergillus species. The species most frequently isolated from the dry-fermented sausages were P. commune (32.4 %), A. proliferans (33 %), and P. solitum (14.8 %), while A. proliferans (52.1 %), P. commune (28.9 %) and P. citrinum (19.7 %) predominated in dry-cured meat products. Aspergillus predominated on the TMPs from southern Croatia, while Penicillium was prevalent on products from the other four regions, possibly due to differences in weather conditions. Seven potentially mycotoxigenic species (A. creber, A. flavus, A. niger, A. westerdijkiae, P. citrinum, P. commune, and P. nordicum) were isolated and identified. Regular monitoring of mould species and their toxigenic metabolites present on traditional meat products is of the utmost importance from the public health perspective, while the results of such a monitoring can prove beneficial for the tailoring of the production technology development.

Flavor evolution of normal- and low-fat Chinese sausage during natural fermentation

This work compared the flavor evolution of normal-fat (NF) with that of low-fat (LF) Chinese sausage during natural fermentation. Higher degree of lipid oxidation occurred in NF sausages, resulting in its faster formation of stable volatile profiles. Faster formation of esters occurred in NF sausage in the initial 10 days, whereas prolonged fermentation reduced the level of ethyl lactate-M, ethyl heptanoate, ethyl hexanoate-D and ethyl pentanoate-D. Gradual reduction of alcohols was observed in both groups, and surge in aldehydes occurred in LF samples during day 20-30 period. Faster formation of taste characteristics and larger amount of 2-methylfuran as well as 2,3-dimethylpyrazine were found in LF sausages, since more free amino acids were liberated in LF sausages. Umami and aftertaste tastes formed in the first 20 days, whereas prolonged fermentation reduced these favorable taste. These results highlight that the choice of proper fermentation duration should largely depend on the fat content in Chinese sausages.

The Influence of Surface Mycobiota on Sensory Properties of “Istarski pršut” and “Dalmatinski pršut”

This study aimed to identify surface mould species overgrowing the Croatian protected meat products “Istarski pršut” and “Dalmatinski pršut” and their effect on sensory properties. Dry-cured hams were produced in 2018/2019 and obtained from annual fairs. The predominant surface species found on “Dalmatinski pršut” were Aspergillus chevalieri, Penicillium citrinum and Aspergillus cibarius, whereas those overgrowing “Istarski pršut” were Aspergillus proliferans, P. citrinum and Penicillium salamii. The results show species diversity, higher presence, and greater variety of Aspergillus species in “Dalmatinski pršut” in comparison to “Istarski pršut”, and significant variations in 9 of 20 sensory attributes. Principal component analysis revealed a clear distinction between the two, and a large contribution of P. salamii and Penicillium bialowienzense to one principal component. The texture traits, smoky odour, muscle and subcutaneous fatty tissue colour, and mould species found are valuable for product characterisation. The results also indicate that mould species may be responsible for some sensory traits, such as tenderness, juiciness, and lesser freshness.

Investigation of fermentation-induced changes in the volatile compounds of Trachinotus ovatus (meixiangyu) based on molecular sensory and interpretable machine-learning techniques: Comparison of different fermentation stages

Fermented golden pomfret (Trachinotus ovatus) is appreciated by local consumers owing to its distinct flavor. Electronic nose (E-nose) and gas chromatography-ion mobility spectrometry (GC-IMS) technologies were used to analyze the changes in volatile compounds responsible for evolution of the golden pomfret odor profile during fermentation. Forty-five ion peaks were detected using GC-IMS. Although aldehydes represented the major initial volatile compound group, their levels decreased as fermentation proceeded. Between 3 and 15 days, increased levels of esters contributed to a stable volatile organic compounds profile. After 18 days, high levels of indole and pyrazines were detected. Eleven key volatile compounds were screened based on partial least squares discriminant analysis (PLS-DA). Back propagation artificial neural network (BP-ANN) predicted the fermentation stage enabling the development of better strategies to regulate golden pomfret fermentation. This study provided a theoretical basis for real-time monitoring and quality control of Chinese fermented golden pomfet.

The Effect of Catabolic Transformations of Proteins and Fats on the Quality and Nutritional Value of Raw Ripened Products from Zlotnicka Spotted and Zlotnicka White Meat

The aim of the study was to compare the advancement of the ripening as well as catabolic changes in proteins and fats of Zlotnicka Spotted (ZS) and Zlotnicka White (ZW) meat and their impact on the quality and nutritional value of ready-to-eat products. The meat of the breeds ZS and ZW differed not only in the basic chemical composition but also in the susceptibility to catabolic transformations of proteins and lipids, which translated into a separate technological and nutritional quality as well as the profile of volatile odor compounds. Loins due to their compact histological structure, low pH (5.4) and decreased water activity (0.92–0.93) were characterized by a lower number of coagulase-negative cocci (3.3 log cfu/g) compared to hams. The products of both breeds differed in the content of selected neutral glucogenic amino acids with a pI in the range of 5.6–6.1 mainly. The content of biogenic amines was therefore completely dependent on the metabolic potential of acidifying bacteria. Larger number of lactic acid bacilli (7.5–7.7 log cfu/g) and lactic acid cocci (7.9–8.3 log cfu/g), as well as a higher content of saturated (55.2–53.7%) and polyunsaturated fatty acids (6.4–7.0%) shaped the final pH of hams (5.3). Presence of aldehydes, ketones and alcohols indicated existing fat oxidation despite the small values of the TBA index of hams (1.1 mg/kg) and loins (0.4–0.6 mg/kg). The volatile compounds that differentiated products of ZS and ZW formed by the oxidation and microbial activity, were, primarily: octanal, 1-hydroxypropan- 2-one, 3-methylpentan-2-one, propane-1,2-diol, 2,5-dimethylfuran and 3-hydroxybutan- 2-one, butane-2,3-dione, butane-1,2-diol, respectively.

A Review: Microbial Diversity and Function of Fermented Meat Products in China

Fermented meat products have a long history in China. These products exhibit a characteristic unique flavor, compact meat quality, clear color, long shelf life and wide variety and are easy to transport. During the processing and storage of fermented meat products, microorganisms are present and exhibit diverse characteristics. Microorganisms can accelerate the degradation of proteins and fats to produce flavor compounds, inhibit the growth and reproduction of heterozygous bacteria, and reduce the content of chemical pollutants. This paper reviews the microbial diversity of Chinese ham, sausage, preserved meat, pressed salted duck, preserved fish and air-dried meat and provides analyses of the microbial compositions of various products. Due to the differences in raw materials, technology, auxiliary materials, and fermentation technology, the microbial species found in various fermented meat products in China are different. However, most fermented meat products in China are subjected to pickling and fermentation, so their microbial compositions also have similarities. Microorganisms in fermented meat products mainly include staphylococci, lactobacilli, micrococci, yeasts, and molds. The study of microbial diversity is of great significance for the formation of quality flavor and the safety control of fermented meat products, and it provides some theoretical reference for the study of fermented meat products in China.

Influence of Muscle Type on Physicochemical Parameters, Lipolysis, Proteolysis, and Volatile Compounds throughout the Processing of Smoked Dry-Cured Ham

The influence of muscle type (biceps femoris, BF and semimembranosus, SM) on physicochemical parameters, volatile compounds, and the extent of proteolysis and lipolysis during the manufacturing of smoked dry-cured ham was investigated. A total of fifty smoked hams were sampled: raw ham, after salting, smoking, drying, and ripening. Almost all physicochemical parameters were affected by muscle type, manufacturing stage and their interactions. SM had lower water, ash, NaCl content, and water activity (aw), while fat and protein content were higher after ripening compared to BF. BF showed higher L*a*b* values compared to SM. The results of texture profile analysis showed that almost all analyzed parameters were influenced by muscle type and production stage. A total of 88 volatile compounds were identified, showing an increase in its number during processing: 31 volatile compounds were identified in raw ham and 72 after the ripening phase. Aldehydes and phenols were the predominant groups of compounds, followed by alcohols, ketones, aromatic hydrocarbons, aliphatic hydrocarbons, esters, and terpenes. Muscle type and production phase significantly affected lipid oxidation and the index of proteolysis: in SM, thiobarbituric acid reactive substances (TBARS) increased faster than in BF, while proteolysis had an opposite effect and was more pronounced in BF.

Effects of different smoking methods on sensory properties, free amino acids and volatile compounds in bacon

BACKGROUND

The aim of this study was to investigate the effects of different smoking methods on sensory properties, free amino acids (FAAs) and volatile compounds (VCs) of bacon. Descriptive analysis was performed using a highly trained panel (n = 9) to evaluate four bacons in sextuplicate. VCs of bacons were analyzed using solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS).

RESULTS

Bacons were significantly different in sensory properties (P < 0.05). Wood smoked bacon (WSB) had a higher smoky and fatty aroma, liquid smoked bacon (LSB) had a higher red color intensity and yellow color intensity, and paper smoked bacon (PSB) had an outstanding texture. Different smoking methods resulted in an increase in total FAAs content, of which paper smoking was significantly higher than the others (P < 0.05). Also, a total of 59 volatile flavor compounds were identified for bacons, aldehydes were the most abundant groups of compounds. Principal component analysis (PCA) can effectively separate the bacons that underwent different smoking methods.

CONCLUSION

The aldehydes and hydrocarbons with high content in PSB improved the overall taste intensity. The color in the sensory attributes was more obvious after LSB processing. The phenols and aromatic hydrocarbons in WSB contributed significantly to the pleasant properties (smoky, fatty). © 2020 Society of Chemical Industry.

Sensory characteristics and volatile compounds of dry cured ham Speck are affected by pig dietary supplementation with antioxidant mixture

BACKGROUND

Dry cured ham named Speck is a typical Italian product, with consolidated processing techniques and specific quality parameters. It has gained importance in the international market after obtaining the Protected Geographical Indication. Recent studies indicate that dietary plant extracts in pig may affect quality of processed meats but there are no data on their effect on Speck. Consequently, the effects of dietary supplementation with antioxidant mixture (AOX), containing vitamin E and polyphenols, in pigs on the nutritional characteristics, volatile compounds, sensory properties and consumers' preference of Speck were evaluated.

RESULTS

The Speck weight loss during seasoning was lower in the AOX group, while products quality parameters were not affected by dietary treatments. Alcohol and terpenes concentrations were lower (P < 0.05) in the AOX samples than the control. Sensory profile revealed slight differences (P < 0.05) in Speck salty and sweet taste, whereas the consumer tests showed a higher (P < 0.05) preference, with mean score of seven, for Speck from pigs fed AOX.

CONCLUSION

Our results provide new insights on the quality parameters of Speck. Dietary integration with antioxidant mixture decreased Speck weight losses during seasoning. Volatile compounds concentrations and sensory profile were slightly affected by dietary treatment. The consumer test revealed that dietary antioxidants, increased the overall preference for Speck, and can potentially increase its consumption. © 2020 Society of Chemical Industry.

Effects of roasting by charcoal, electric, microwave and superheated steam methods on (non)volatile compounds in oyster cuts of roasted lamb

This work was conducted to compare (non)volatile compounds and sensory evaluation of oyster cuts of roasted lamb. Three newer roasting methods, namely electrically heated air (EHA), microwave heat (MWH) and superheated steam (SHS), were compared with traditional burning charcoal (BCC). The results showed that the 3 new roasting methods all generated rich nonvolatile compounds and volatile compounds in samples, which was similar to the results of those prepared by BCC. Particularly, the EHA produced more nonvolatile compounds and higher equivalent umami concentrations than the other new methods, especially regarding umami amino acids. Moreover, the EHA and SHS methods had better sensory evaluations than the MWH, including acceptability, fat and roast flavours, and they had better odour activity values (OAVs) of characteristic volatile compounds, such as octanal, nonanal and (E, E)-2,4-decadienal. It was concluded that the EHA might be a potential method to replace the BCC due to our findings about nonvolatile compounds, OAVs of volatile compounds and sensory evaluation.

Comparative analysis of characteristic volatile compounds in Chinese traditional smoked chicken (specialty poultry products) from different regions by headspace-gas chromatography-ion mobility spectrometry

This article presents investigation of the flavor profile on 5 different regional Chinese smoked chicken samples using gas chromatography−ion mobility spectrometry analysis methods. Five batches of samples were obtained over the course of 6 mo. A total of 34 flavor substances were identified in the 5 smoked chicken samples, including 10 aldehydes, 7 alcohols, 4 ketones, 2 hydrocarbons, 3 heterocyclic compounds, 4 esters, 2 ethers, and 2 phenolic compounds. The whole spectral fingerprint visually displayed flavor differences and relations in 5 types of smoked chicken with local characteristics. Moreover, the orthogonal projections to latent structures discriminant analysis model revealed that these samples could be separately classified into 5 groups. Multivariate statistical analysis showed that 20 chemicals with higher Variable Importance for the Projection values were the key contributors to the differences of flavor in these 5 kinds of smoked chicken. N-nonanal, heptanal, n-nonanal, heptanal, furfurol, and hexanal were the main common flavor compounds in the 5 types of Chinese smoked chicken, whereas linalool, alpha-terpineol, 1,8-cineole, and anethole were the main characteristic flavor compounds of Goubangzi chicken (No. 1); gamma-butyrolactone, 2-acetylfuran, 2-methoxyphenol, 2-acetylpyrrole, and limonene were determined as the key flavor compounds of Liaocheng chicken (No. 2); the concentration of octanal and n-nonanal was higher in Tangqiao chicken (No. 3); butyl acetate was the key contributor to the flavor compounds of Jinshan chicken (No. 4). 2-Heptanone and 2-pentylfuran had a high correlation with Zhuozishan chicken (No. 5). The different raw materials and ingredients used, especially the method of preparation and cultural differences, in different regions of the country in China were the main reasons leading to the similarities and differences of volatile compounds in the 5 kinds of Chinese traditional smoked chicken.

Evolution of volatile compounds and physical, chemical and sensory characteristics of Toscano PDO ham from fresh to dry-cured product

Physical and chemical changes in Toscano ham lean were evaluated according to three different seasoning time (14, 16 and 18 months). Moreover, on Semimembranosus muscle, the volatile profile at 0, 1, 3, 6, 12, 14, 16 and 18 months of seasoning was determined by SPME–GC–MS. Eventually, a quantitative-descriptive sensory evaluation was performed. Longer seasoning times led to a decrease of Chroma in Biceps femoris, and also protein and proteolysis index decreased as the seasoning time increased. A total of 97 volatile compounds (VOCs) belonging to seven chemical families (29 aldehydes, 16 esters, 14 alcohols, 13 hydrocarbons, 12 ketones, 10 acids, 2 furans and 1 nitrogenous compound) were identified. Sensory evaluation outlined the major differences between 18th months ham and the other two classes, with the former being harder and with a slight presence of off flavor and off odor. The VOCs evolution during curing was studied and a multivariate approach was performed to test the feasibility of using the VOCs profile to predict the curing stage of Toscano ham. The discriminant analysis successfully managed to separate the samples of 0–6 months from the ones of 12–18 months using 26 of the identified VOCs. Among them, pentane 2,3-dimethyl, acetophenone and 9-decenoic acid were strong discriminants for 0–6 months hams, while dodecanoic, benzeneacetaldehyde, 3-octen-2-one and pentanoic acid ethylester were linked to 12–18 months hams. Within the high maturing classes (12, 14, 16, 18 months of seasoning), the 17 discriminating compounds identified successfully allocated only 12 and 18 months samples. The main VOCs associated with the “12 months” class were nonanal, 1,5-diphenyl-3-methylthio-1,2,4-triazole and 6-methoxy 2-hexanone. The “18 months” seasoning class, instead, was identified by 1,5-diphenyl-3-methylthio-1,2,4-triazole, phenol and l,2-butoxy ethanol.

Evaluation of physicochemical properties and volatile compounds of Chinese dried pork loin curing with plasma-treated water brine

The application of dielectric barrier discharge cold plasma (DBD-CP)-treated water as a novel curing process for manufacturing Chinese dried pork loin was investigated. The treatment time of DBD-CP was optimized based on the pH and nitrite level of the plasma-treated water (PTW). PTW treated for 3 min had an alkaline environment and a higher nitrite content than that at the other lengths of treatment time. Pork loins were marinated in control or PTW brine at 4 °C for 24 h and then dry-ripened for 15 days. PTW with a higher treatment voltage significantly decreased lipid oxidation of the products and led to an increased a* value (redness) and an increased residual nitrite content in products that was still within the range of use (all P < 0.05). The contents of each free amino acid increased with increasing treatment intensity (P < 0.05). There were 22 new volatile compounds generated in PTW-cured products, such as 3-methyl-butanol, hexanal and 2,3-octanedione, while six substances were lost, such as 2-pentylfuran, compared with those in the control. This study indicates that using PTW as a curing method can be a potential and effective way of producing dried pork meat products.

Sensory Characteristics of Combinations of Phenolic Compounds Potentially Associated with Smoked Aroma in Foods

The sensory characteristics of phenolic compounds combinations were evaluated. A highly trained descriptive panel evaluated combinations of chemicals (two chemicals at a time) containing either one smoky aroma and one non-smoky aroma chemical compound, two smoky aroma chemicals, or two non-smoky aroma chemicals. The non-smoky compounds had been associated with smoke aroma in other studies, but were not found to be smoky when tested individually. Smoked flavor characteristics and intensities were changed significantly when two phenolic compounds were combined. Non-smoky phenolic compounds often contributed the smoked flavor when combined with one smoky phenolic compound or another non-smoky phenolic compound. It is necessary to understand the sensory characteristics of compound combinations as well as individual compounds.

Quantitative determination of residual 1,4-dioxane in three-dimensional printed bone scaffold

Background/Objective

A novel porous scaffold poly (lactide-co-glycolide) and tricalcium phosphate (PLGA/TCP) was developed by three-dimensional printing technology for bone defect repair. As a Class 2 solvent with less severe toxicity, content of residual 1,4-dioxane in this newly developed scaffold should be rigorously controlled when it is translated to clinical use. In this study, a headspace gas chromatography-mass spectrometric (HS-GC-MS) method and related testing protocol were developed for quantitative determination of 1,4-dioxane in the PLGA/TCP composite scaffolds.

Methods

Matrix effect analysis was used to optimise the pretreatment method of the scaffolds. Then, the procedure for testing 1,4-dioxane using HS-GC-MS was set up. The accuracy, precision, and robustness of this newly developed quantitative method were also validated before quantification of 1,4-dioxane in the scaffolds with different drying procedures.

Results

Dimethyl formamide (DMF) was the optimal solvent for dissolving scaffolds for GC-MS with proper sensitivity and without matrix effect. Then, the optimised procedure was determined as: the scaffolds were dissolved in DMF and kept at 90°C for 40 minutes, separated on a HP-5MS column, and detected by mass spectroscopy. Recovery experiments gave 97.9–100.7% recovery for 1,4-dioxane. The linear range for 1,4-dioxane was determined as 1–40 ppm with linear correlation coefficient ≥ 0.9999. Intraday and interday precision was determined as being within relative standard deviation of below 0.68%. The passable drying procedure was related to lyophilising (−50°C, 50 Pa) the scaffolds for 2 days and drying in vacuum (50 Pa) for 7 days.

Conclusion

This is the first quantitative method established to test 1,4-dixoane in a novel scaffold. This method was validated with good accuracy and reproducibility, and met the methodological requirements of the Guideline 9101 documented in the Chinese Pharmacopoeia 2015 Edition.

The translational potential of this article

This quantitative method for determination of residual 1,4-dioxane in the novel scaffolds is a key technical method during its translation into clinical use because this method is an important and indispensable file in the enterprise standard when the porous scaffold is registered as a Class III implanted medical device for bone defect repair, which is used to guarantee the safety of the scaffolds. It is also applied to optimise the drying process of scaffolds and to monitor the quality of scaffolds in the industrialisation process. Further, this method provides references for other solvents quantitative determination in porous scaffolds or materials.

Differentiation of dry-cured hams from different processing methods by means of volatile compounds, physico-chemical and sensory analysis

The aim of this study was to characterize dry-cured hams from four different processing methods (differences in primary leg treatment, salting and smoking phase). Volatile compounds were isolated by using headspace-solid phase microextraction and analysed by gas chromatography/mass spectrometry (GC/MS). Samples were also evaluated by sensory and physico-chemical characteristics (moisture, protein, fat and NaCl content, a_w, colour). 149 volatile compounds of dry-cured hams were identified and 15 of them were quantified. Identified volatile compounds belonged to several classes of chemical: 25 aldehydes, 18 phenols, 12 alcohols, 16 terpenes, 27 aromatic hydrocarbons, 18 aliphatic hydrocarbons, 17 ketones, 9 esters and 7 acids. Most abundant volatiles in ham samples were aldehydes (34.46-49.78%). Principal component analysis showed a good separation among groups. Smoked dry-cured hams showed a higher content of phenols, aromatic hydrocarbons, and acids and were characterized by smoky aroma, while non-smoked dry-cured hams showed higher content of terpenes, ketones, alcohols, esters, aliphatic hydrocarbons and were characterized with spicy aroma.