Understanding the implications of current health trends on the aroma of wet and dry cured meat products

Textured vegetable protein as a partial replacement for lean meat in salami analogues: Perspectives on physicochemical properties, flavour and proteome changes

Integrating plant proteins into meat products offers a sustainable way to reduce the environmental impact of meat consumption while satisfying the growing flexitarian population. This study explored the effects of textured vegetable proteins (TVPs) on the physico-chemical attributes and flavour profile of hybrid salamis using 4D label-free proteomics. Results showed that hybrid salamis had lower pH, reduced water activity and increased weight loss compared with traditional salamis, along with greater hardness and a slightly rough, porous texture with a filamentous structure. TVPs substantially modified crucial meaty flavour compounds (nitrogen oxides, sulfides and pyrazine), increasing heightening sourness and bitterness while diminishing umami. Proteomic analysis revealed significant upregulation of myosin and actin in hybrid salamis; notably, these proteins were involved in glycerol-3-phosphate dehydrogenase activity and calcineurin-mediated signalling, underscoring their role in flavour enhancement. Therefore, hybrid salamis offer an attractive alternative to traditional salamis by merging meat-like taste and texture with plant protein.

Astral-based DIA proteomics explored the flavor enhancement mechanism of Chinese traditional smoked bacon by staphylococcal co-fermentation

The proteolysis pattern during mixed fermentation of Staphylococcus cohnii WX-M8 and S. saprophyticus MY-A10 on Chinese bacon was still unknown. In this study, the changing laws of protein degradation products during staphylococcal mixed fermentation were analyzed, followed by an investigation of endogenous enzymes and cellular components, and finally an examination of flavor profiles. Results indicated that mixed fermentation improved protein degradation and promoted the production of peptides and free amino acids (FAAs). Proteolysis of S. saprophyticus MY-A10 was non-specific, and it promoted protein degradation by cooperating with cathepsin L1. S. cohnii WX-M8 was specific and acted mainly with calpain-3 in the thin filament. The fulfillment of S. cohnii WX-M8 function was enhanced in the presence of S. saprophyticus MY-A10. Mixed fermentation showed synergism with endogenous peptidases in degrading peptides to small-molecule peptides or FAAs and complementarity with endogenous dehydrogenases in converting FAAs to volatile organic compounds (VOCs).

Evaluation of the effect of dietary supplementation with Allium mongolicum regel bulb powder on the volatile compound and lipid profiles of the longissimus thoracis in Angus calves based on GC-IMS and lipidomic analysis

The effect of A. mongolicum Regel bulb powder (AMRP) supplementation on the flavour of beef from Angus calves has not been investigated thus far. We used GC-IMS and untargeted lipidomics techniques to examine the volatile compound and lipid metabolic profiles and reveal the effects of dietary AMRP supplementation on the flavour of beef. A total of 6 characteristic volatile compounds and 30 key lipid compounds were identified in the AMRP treatment group. AMRP promoted the release of triglycerides and phosphatidylinositols from beef and accelerated the production of volatile compounds such as ethyl acetate, 1-penten-3-one, and tetrahydrofurane, and the production of these three characteristic volatile compounds was significantly correlated with the UFAs in triglycerides according to correlation analysis. In summary, dietary AMRP supplementation had a positive effect on the flavour of beef, and these findings provide a theoretical basis for the development and utilisation of AMRP as a feed additive.

Poly(3-hydroxybutyrate) production for food packaging from biomass derived carbohydrates by cupriavidus necator DSM 545

The extensive utilization of conventional plastics has resulted in a concerning surge in waste. A potential solution lies in biodegradable polymers mostly derived from renewable sources. Cupriavidus necator DSM 545 is a microorganism capable, under stress conditions, of intracellularly accumulating Poly(3-hydroxybutyrate) (PHB), a bio-polyester. This study aimed to identify optimal conditions to maximize the intracellular accumulation of PHB and its global production using natural media obtained by processing lignocellulosic residues of cardoon, a low-cost feedstock. An intracellular PHB accumulation was observed in all of the tested media, indicating a metabolic stress induced by the lack of macronutrients. Increasing C/N ratios led to a significant decrease in cellular biomass and PHB production. Furthermore C. necator DSM 545 was incapable of consuming more than 25 g/L of supplied monosaccharides. Surprisingly, in the samples supplied with 60 % of the pentose-rich liquid fraction, complete consumption of xylose was observed. This result was also confirmed by subsequent tests using Medium 1 growth media containing xylose as the sole carbon source. Using a diluted medium with a C/N ratio of 5, a PHB production of 5.84 g/L and intracellular PHB accumulation of 77 % w/w were respectively achieved. Finally, comparative shelf-life tests conducted against conventional pre-packaging materials in PP suggested that PHB films performed similarly in preserve ready-to-eat products.

Quality changes due to refrigerated storage in a traditional dry-cured pork belly salted with glasswort or KCl as partial substitutes for NaCl

BACKGROUND

Glasswort represents a novel alternative to KCl for replacing sodium in meat products. To evaluate the effects of Na reduction on the quality changes of a traditional dry cured belly due to storage, fresh bellies were dry-salted with 2% NaCl (BCON), with 2% of a mixture containing 50% NaCl and 50% KCl (BKCl) or with 1% of a mixture of 90% NaCl and 10% powdered glasswort (BGW), dry-cured, sliced, vacuum packaged and stored under refrigeration for 60 days.

RESULTS

The BKCl and BGW bellies were lower in sodium by one-third to one-half compared to BCON (with 1.6 g Na/100 g). Neither BKCl, nor BGW significantly differed from BCON in free fatty acids (FFA) before and after storage, whereas BGW showed almost twice as much 2-methylbutanal content as BCON. All bellies showed microbiological stability during storage. Micrococcaceae was the most abundant microbial group with values of 105 to 106 colony-forming units g-1. The BGW presented higher Micrococcaceae counts (approximately one log unit) but lower microbial biodiversity than BCON.

CONCLUSION

The two alternative dry salting methods reduced the sodium content in bellies, at the same time as ensuring chemical and microbiological stability during refrigerated vacuum storage. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Ultrasound effect on flavor profile of beef jerky produced with partial potassium salt substitute based on GC-IMS technology

Traditional beef jerky contains a high content of sodium salt while the reduction of sodium usage impairs the flavor of final product. Regarding above issues, this research innovatively applied ultrasound-assisted salts (NaCl and KCl) recombination in the pickling stage of low-sodium beef jerky, and further compared the flavor differences caused by ultrasound by sensory evaluation, E-nose and GC-IMS. Besides, the changes of physicochemical qualities were explored including salts content, color and shear force. Results showed that ultrasound had positive impacts on flavor quality. The 400 W treatment was chosen as an optimal group for flavor improvement which was mainly related with the increased level of 5 aldehydes (nonanal, 3-methylbutanal, heptanal, pentanal and octanal) and the decreased level of 3 ketones (2-butanone, 2-pentanone and 2,3-pentanedione). Simultaneously, ultrasound increased the redness and tenderness of final product. Thus, ultrasound is a promising approach for improving the flavor of low-sodium beef jerky.

Dry-Cured Sausages "Salchichón" Manufactured with a Valorized Ingredient from Red Grape Pomace (Var. Tempranillo)

The inclusion of an ingredient made from red grape pomace (RGP) var. Tempranillo was evaluated for the preservation of a traditional dry-cured sausages (salchichón). The pomace was valorized through thermal blanching (103 °C for 1 min) and hydrostatic high-pressure treatment (600 MPa/5 min) before the addition to salchichón. Four formulations of salchichón were evaluated, including a negative control (NC-without red grape pomace or synthetic additives), positive control (PC-with ascorbic acid and nitrites), low level (LL-0.5%), and high level (HL-1%) of RGP. Physicochemical, microbiological, and sensorial effects were analyzed. RGP reduced the final pH of salchichón and favored the growth of lactic acid bacteria at similar levels as PC. The addition of ascorbic acid and nitrites resulted in a final product with a redder and less yellow color than the other formulations. This cured color was not reached with the addition of RGP. However, its inclusion slightly reduced lipid and protein oxidation in salchichón. PC showed high levels of sulfur and terpene levels in a volatile profile, although at a sensory level, only differences in spicy taste were not noticed by panelists. The incorporation of the ingredient could enable the substitution of nitrites with valorized red grape pomace in sausages, although the desirable color achieved with nitrifying salts was not fully attained.

From detection methods to risk prevention: Control of N-nitrosamines in foods and the role of natural bioactive compounds

Food processing unavoidably introduces various risky ingredients that threaten food safety. N-Nitrosamines (NAs) constitute a class of food contaminants, which are considered carcinogenic to humans. According to the compiled information, pretreatment methods based on solid-phase extraction (SPE) were widely used before the determination of volatile NAs in foods. The innovation of adsorbents and hybridization of other methods have been confirmed as the future trends of SPE-based pretreatment methods. Moreover, technologies based on liquid chromatography and gas chromatography were popularly applied for the detection of NAs. Recently, sensor-based methods have garnered increasing attention due to their efficiency and flexibility. More portable sensor-based technologies are recommended for on-site monitoring of NAs in the future. The application of artificial intelligence can facilitate data processing during high-throughput detection of NAs. Natural bioactive compounds have been confirmed to be effective in mitigating NAs in foods through antioxidation, scavenging precursors, and regulating microbial activities. Meanwhile, they exhibit strong protective activities against hepatic damage, pancreatic cancer, and other NA injuries. Further supplementation of data on the bioavailability of bioactives can be achieved through encapsulation and clinical trials. The utilization of bioinformatics tools rooted in various omics technologies is suggested for investigating novel mechanisms and finally broadening their applications in targeted therapies.

Strategies to Reduce Salt Content: PDO and PGI Meat Products Case

The reduction of sodium chloride (NaCl) content, commonly known as salt, in processed meat products is one of the objectives of health organizations and government authorities to achieve healthier products. This reformulation of traditional meat products with protected designations poses more constraints, as they have a more consolidated quality image and less margin for change, since consumers appreciate the products for their unique sensory characteristics. The aim of this work is to present some of the strategies that have been explored to obtain meat products with low sodium content. Information related to the characteristics of traditional meat products with quality marks and geographical indications in different studies is discussed in opposition to the information recorded in their product specifications. It was found that the product specifications of meat products with Portuguese Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) show a wide variation in the NaCl content, much higher than the recommended values. Thus, one of the requirements to be implemented will be the parameterization of NaCl levels and their monitorization by control and certification organizations as a way to ensure product quality. It is also urgent to examine whether healthy innovation strategies may affect the quality of traditional PDO or PGI meat products and whether they can be included in the respective product specifications.

Tri-frequency simultaneous ultrasound pickling for the acceleration of the NaCl content and quality improvement of pork (longissimus dorsi)

BACKGROUND

The pickling process with NaCl is an essential step for pork preservation. This study aimed to investigate the effect of different ultrasonic intensities of tri-frequency simultaneous ultrasound (TSIU) pickling on the NaCl content and quality of pork (longissimus dorsi). After 30 min pickling, the NaCl content, moisture content, pickling yield, cooking loss, textural properties, color, pH, moisture migration and distribution as well as microstructure of pork were assessed.

RESULTS

Results showed that among all the ultrasonic treatment intensities (85-150 W L-1), the NaCl content of the sample pickled by an intensity of 101.3 W L-1 was higher than that of other intensities. TSIU 101.3 W L-1 showed 59.95% higher NaCl content than the control sample. In addition, the sample treated with TSIU of 101.3 W L-1 had higher pickling yield and moisture content, better textural properties of pork (including hardness and chewiness), and less cooking loss. The results of the low-field nuclear magnetic resonance showed that, compared with the control group, the relaxation time T21 of the ultrasound-assisted pickling samples increased, while the proportion of T22 (A22) reduction ranged from 175.0% to 379.9%. The microstructure designated that the ultrasonic treatment could facilitate changes in meat texture.

CONCLUSION

Ultrasound marination of different intensities promoted the diffusion of NaCl and affected the quality of pork tenderloins. The TSIU at 101.3 W L-1 could better accelerate NaCl transport and homogeneous distribution on meat, thereby improving the sample quality. © 2024 Society of Chemical Industry.

Improvement mechanism of volatile flavor in fermented tilapia surimi by cooperative fermentation of Pediococcus acidilactici and Latilactobacillus sakei: Quantization of microbial contribution through influence of genus

Single starter can hardly improve the volatile flavor of fermented fish surimi. In this study, the changes of volatile compounds (VCs) and microbial composition during cooperative fermentation of Latilactobacillus sakei and Pediococcus acidilactici were studied by headspace solid-phase microextraction gas chromatography-mass spectrometry and 16S rRNA gene high-throughput sequencing. During cooperative fermentation, most VCs and the abundance of Latilactobacillus and Lactococcus significantly increased, while Pediococcus, Acinetobacter, and Macrococcus obviously decreased. After evaluation of correlation and abundance of each genus, Latilactobacillus and Lactococcus possessed the highest influence on the formation of volatile flavor during cooperative fermentation. Compared with the natural fermentation, cooperative fermentation with starters significantly enhanced most of pleasant core VCs (odor activity value≥1), but inhibited the production of trimethylamine and methanethiol, mainly resulting from the absolutely highest influence of Latilactobacillus. Cooperative fermentation of starters is an effective method to improve the volatile flavor in the fermented tilapia surimi.

New insights into the dominance of mixed fermentation of Staphylococcus cohnii and Staphylococcus saprophyticus in Chinese bacon: Complete genomic and comparative genomic perspectives

Previous studies have demonstrated that Staphylococcus cohnii WX_M8 and S. saprophyticus MY_A10 significantly enhanced the flavor of Chinese bacon in a mixed fermentation. However, due to the complexity of the processing, the contribution of the bacteria is deceptive when investigating only the phenotypic changes at the time of fermentation. In order to clarify the metabolic mechanisms of mixed fermentation, a technological characterization, whole genome and comparative genomics analysis, and metabolites were approached in this study. Results showed that differences in tolerance characteristics existed between WX_M8 and MY_A10. And the genomes of both the two strains consisted of one chromosome and four circular plasmids. Their genome sizes were 2.74 Mp and 2.62 Mp, the GC contents were 32.45% and 33.18%, and the predicted coding genes (CDS) were 2564 and 2541, respectively. Based on the annotation of gene functions and assessment of metabolic pathways in the KEGG database, WX_M8 and MY_A10 strains were found to harbor complete protein degradation and amino acid metabolic pathways, pyruvate and butanol metabolic pathways, and isoleucine metabolic pathways, and their diverse enzyme-encoding genes superimposed the metabolic functions, whereas the alcohol dehydrogenase genes, adh and frmA, achieved complementary functions in the production of esters. Comparative genomics analysis revealed a diversity of encoding genes of aminotransferases and a greater metabolism for sulfur-containing amino acids, aromatic amino acids, and branched-chain amino acids in the mixed fermentation of strains WX_M8 and MY_A10. Metabolites analysis showed that MY_A10 focused on the production of soluble peptides and free amino acids (FAAs), while WX_M8 focused on volatile organic compounds (VOCs), resulting in a significant enhancement of the flavor of Chinese bacon when the two were mixed fermented. This result may provide direction for strains WX_M8 and MY_A10 to be used as starter cultures and targeted to regulate flavor.

Inoculation fermentation with Lactobacillus fermentum L28 and Staphylococcus epidermidis S24 for improving the protein degradation of air-dried goose

The inoculation fermentation technology was applied to the processing of dried cured goose to investigate the protein degradation. Lactobacillus fermentum (L), Staphylococcus epidermidis (S) and mixed strains (L + S) were individually inoculated into the whole goose before drying. We studied the degradation of protein in the air-dried period of goose. The results showed that compared with natural fermentation, inoculation fermentation significantly increased the content of non-protein nitrogen (14.85 mg/g NPN), proteolysis index (8.98% PI), myofibril fragmentation index (89.35 MFI) and total amount of free amino acids (1332.6 mg/g FAA) of dried cured goose. Electrophoresis revealed that the inoculation fermentation accelerated the degradation of macromolecular proteins and the accumulation of small molecular proteins. The degree of protein degradation in four groups of goose was in an order of L + S group > S group > L group > CK group. It suggested that inoculation fermentation could promote the degradation of myofibrillar proteins.

Characterization the microbial diversity and metabolites of four varieties of Dry-Cured ham in western Yunnan of China

In this study, high-throughput sequencing and metabolomics analysis were conducted to analyze the microbial and metabolites of dry-cured Sanchuan ham, Laowo ham, Nuodeng ham, and Heqing ham that have fermented for two years produced from western Yunnan China. Results showed that at the genus level, the dominant bacteria in the four types of ham were Halomonas and Staphylococcus, while the dominant fungi were Aspergillus and Yamadazyma. A total 422 different metabolites were identified in four types of ham, mainly amino acids, peptides, fatty acids, and their structural analogs, which were involved in pantothenate and coenzyme A biosynthesis, caffeine, and tyrosine metabolism. The dominant microorganisms of the four types of ham were mainly related to the metabolism of fatty acids and amino acids. This research enhances the identification degree of these four types of dry-cured ham and provides a theoretical basis for developing innovative and distinctive ham products.

The effect of instant tea on the aroma of duck meat

Tea products, such as instant tea, have been shown to improve the aroma of meat products. However, the mechanisms by which tea products enhance meat aroma have not been adequately explained. In this study, we analyzed the impact of instant tea on the aroma of duck meat. Our results showed that treatment with instant tea led to increases in floral, baked, and grassy notes while reducing fishy and fatty notes. Several alcohols, aldehydes, ketones, indole and dihydroactinidiolide exhibited significantly increased OAVs. Conversely, certain saturated aldehydes, unsaturated aldehydes and alcohols displayed significantly decreased OAVs. The enhanced floral, baked and grassy notes were attributed to volatile compounds present in instant tea. The reduction in fishy and fatty notes was linked to polyphenols in instant tea interacting with nonanal, undecanal, (E)-2-octenal, (E)-2-nonenal, (E)-2-decenal, and 2,4-decadienal through hydrophobic interactions and electronic effects. This study enhances our understanding of how tea products improve meat aromas.

A study on the catalytic domain of pork phospholipase A2: Enzymatic properties and hydrolysis characteristics of phosphatidylcholine and its hydroperoxide

Endogenous phospholipase A2 (PLA2) plays an important role in phospholipids degradation during cured meat products manufacturing. The present study was undertaken to reveal more information about the endogenous PLA2 in muscles and its role in degradation of intramuscular phospholipids. With the catalytic domain of pork calcium-independent PLA2 (iPLA2cd), impacts of physic-chemical factors on the activity were investigated and substrate specificity of the enzyme were tested respectively. The optimum temperature and pH of pork iPLA2cd were 40 °C and 7.5, respectively. The iPLA2cd could be stimulated by adequate contents of NaCl and ATP, and inhibited by CaCl2 and NaNO2. For native phospholipids, the iPLA2cd was of a little higher affinity towards phosphatidylcholine (PC) than phosphatidylethanolamine (PE), phosphoserine (PS) and phosphatidylinositol (PI). The iPLA2cd could preferentially hydrolyze peroxidized PC over the native PC. The results would help better understand the degradation of phospholipids and the role played by endogenous enzymes during meat products manufacturing.

Effect of staphylococci fermentation and their synergistic Lactobacillus on the physicochemical characteristics and nonvolatile metabolites of Chinese bacon

The impacts of Staphylococcus cohnii, S. saprophyticus and their synergistic Lactobacillus plantarum on the quality and flavor of Chinese bacon were investigated by monitoring the physicochemical characteristics and characterizing metabolites with non-targeted metabolomics. Results showed that S. cohnii could increase the tenderness and decrease the oxidation of muscle, while S. saprophyticus stabilized the springiness and increased the proteolysis. The metabolites produced by the co-fermentation of S. cohnii and S. saprophyticus showed a higher hierarchy, then exhibited the highest hierarchy in synergy with L. plantarum. The promising flavor may be related to the arginine biosynthesis, nicotinic acid and nicotinamide metabolism, and pyrimidine metabolism pathways. Staphylococcus contributed to flavor by promoting the accumulation of di- and tripeptides and activating the amino acid metabolic pathway through arginine metabolism. These findings provide thoughts for understanding the fermentation mechanism of Staphylococcus and the targeted modulation of the flavor of Chinese bacon.

Formation and improvement mechanism of physical property and volatile flavor of fermented tilapia surimi by newly isolated lactic acid bacteria based on two dimensional correlation networks

Fermentation is an effective way to improve the gel properties of freshwater fish surimi. In this study, two newly isolated Lactiplantibacillus plantarum H30-2 and Pediococcus acidilactici H30-21 were used to improve the physical properties and volatile flavor of fermented tilapia surimi. L. plantarum H30-2 quickly improved the whiteness, gel strength, hardness, and chewiness within 18 h. Among 172 volatile compounds analyzed by HS-SPME-GC-MS, most pleasant core flavor compounds (OAV ≥ 1) were improved by L. plantarum H30-2. L. plantarum H30-2 could always adapt to the surimi environment while P. acidilactici H30-21 could not. Two dimensional correlation networks showed that Lactiplantibacillus and Lactococcus were responsible for the quality formation in surimi during natural fermentation or with starters, while the quality improvement after L. plantarum H30-2 addition mainly resulted from the increasing Lactiplantibacillus and its higher acetic acid production. L. plantarum H30-2 can be developed as a special starter using for tilapia surimi fermentation.

Two Debaryomyces hansenii strains as starter cultures for improving the nutritional and sensory quality of dry-cured pork belly

Dry-cured meat products are gaining attention owing to their distinctive sensory characteristics and health benefits. In this study, two Debaryomyces hansenii strains were investigated for their potential as starter cultures for dry-cured pork belly products. After preliminary screening, these D. hansenii strains, namely, S20 and S26, both exhibiting with excellent aroma-producing capacity in a dry-cured meat model, were selected as single-strain starter cultures. For comparison, a non-inoculated control was also evaluated. In S20- and S26-inoculated pork belly, yeast dominated the microbiota and improved microbiological safety by suppressing Enterobacteriaceae growth. Compared with the non-inoculated control, the inoculated pork belly yielded higher hardness and redness (a*) values. Starter culture inoculation accelerated proteolysis in pork belly, improving the content of total free amino acids (TFFAs) and several essential free amino acids (Thr, Val, Met, Ile, Leu, and Phe) at the end of processing. Moreover, the inoculated samples exhibited higher levels of fat oxidation-derived aldehydes as well as esters, acids, alcohols and other compounds than the non-inoculated control at the end of the 95-day ripening period. Overall, these findings provide new insights into the application of D. hansenii isolated from dry-cured ham to dry-cured pork belly.

Efficient preparation of oyster hydrolysate with aroma and umami coexistence derived from ultrasonic pretreatment assisted enzymatic hydrolysis

In the study, an efficient protease Neutrase®-Flavourzyme® (NF) was screened to prepare the umami-aroma flavor oyster hydrolysate. The effect of protease and ultrasonic pretreatment (UP) assisted by the optimal protease on the flavor substances was investigated. The results demonstrated that the optimal UP-NF (450 W) showed a higher amino acid nitrogen content of 0.34 g/100 mL compared to the NF, and 19 major aroma compounds including octanal, decanal, nonanal, benzaldehyde, 2-undecanone, and 1-octen-3-ol were obtained. Additionally, the free amino acid and fatty acid spectrum indicated that the formation of flavor compounds was primarily due to the oxidation of linoleic and linolenic acids and the degradation of amino acids. Furthermore, taste analysis proved that increased umami and saltiness resulted from the accelerated release of Glu, Asp and 5'-IMP. Overall, UP-NF proved to be an effective method for producing umami-aroma flavor, facilitating further processing of oyster products for the application.

Effects of curing concentration and drying time on flavor and microorganisms in dry salted Spanish mackerel

This study investigated the quality changes of dry salted mackerel during curing and drying process and the relationship between flavor substances and microorganisms. The results showed that the thiobarbituric acid reactive substances (TBARS) values increased gradually with the increase of salt concentration and treatment time. The total volatile base nitrogen (TVB-N) values and total viable counts (TVC) values showed the same trend. Under 3% condition, the TVB-N values exceeded the standard and was not suitable for consumption. A total of 61 volatile flavor substances were identified by Gas chromatography-ion mobility spectrometry (GC-IMS), among which aldehydes contributed the most. Staphylococcus and Cobetia were the most abundant by High-throughput sequencing (HTS). There was significant correlation between TOP15 microorganisms and TOP20 flavor substances. Staphylococcus and Cobetia were positively correlated with 13 volatile flavor substances, which contributed to the formation of flavor in naturally fermented Spanish mackerel.

Mechanism of salt effect on flavor formation in lightly-salted large yellow croaker by integrated multiple intelligent sensory and untargeted lipidomics analyses

Salt has a great influence on food flavor formation. In this study, electronic tongue and nose, gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, and lipid oxidation levels were used to investigate the influence of different NaCl concentrations on the flavor formation of lightly salted large yellow croaker. The results showed that salt improves the sensory characteristics of the product. Hexanal, 2,5-octanedione, octanal, 1-octen-3-ol, nonanal, and heptanal were key flavor compounds. Phospholipids containing 18-carbon fatty acids are major flavor precursor substances. The TBARS values in samples increase with the increase of salt levels significantly (p < 0.05). Products marinated in 6% NaCl showed the highest lipase activity. Thus, NaCl promotes the hydrolysis and oxidation of phospholipids by increasing lipase activity to produce key flavor substances. This study provides valuable insights into the effects of NaCl on flavor formation, which may help to regulate the flavor of salt-reduced food.

Staphylococcus inoculation enhances the sensorial attributes of Chinese bacon by coordinating the composition of flavor compounds through amino acid metabolism

In this study, we aimed to uncover the potential underlying mechanisms of the flavor modulation of Chinese bacon by Staphylococcus. To that end, taste-enhancing S. cohnii WX-M8 and S. saprophyticus MY-A10 screened from Chinese bacon were used to investigate the effects of their individual and mixed fermentations and their synergistic fermentation with Lactobacillus plantarum BL-1 on the sensorial attributes, physicochemical properties, microbial diversity, and volatile compounds (VOCs) of Chinese bacon. Our results revealed that S. cohnii WX-M8 and S. saprophyticus MY-A10 significantly increased a* (redness) and Aw and reduced thiobarbituric acid reactive substances (TBARS) when fermented in a mixture. Moreover, they promoted the formation of esters, aldehydes (especially straight-chain aldehydes), and phenolic compounds through pathways related to amino acid metabolism, enhancing sensorial attributes. While synergistic fermentation with L. plantarum BL-1 resulted in an improved a* (redness) of Chinese bacon, and the increased microbial metabolism of the carbohydrate and lipid metabolic pathways, the increase in TBARS and the higher content of acidic volatiles, led to a change in the composition of the flavor substances. The advantage of co-fermentation of Staphylococci in sensory attributes can be attributed to their capability to metabolize amino acids and associates. These findings provide insights into the role of Staphylococcus as a starter in regulating bacon flavor.

Flavor enhancement during the drying of scallop (Patinopecten yessoensis) as revealed by integrated metabolomic and lipidomic analysis

Dried scallops are a typical shellfish commodity, but the molecular change mechanism in the drying process is not clear. In this paper, the effect of drying on the flavor of scallops was revealed by integrated metabolomic and lipidomic analysis. The results showed that 70 °C was the best temperature for hot air drying, and the moisture content of the scallops was less than 20% after 12 h of drying, which meets the commercial standards for dried scallops. A total of 53 volatile compounds were detected in dried scallops, of which 2,5-dimethyl pyrazine and tetramethyl pyrazine, as characteristic flavor compounds, changed significantly during drying. In addition, taste peptides such as Arg-Gly and Gly-Gly, produced by protein degradation during drying, may contribute to the umami perception of dried scallops. This study helped to increase the overall quality of dried scallops.

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.

Dynamic changes in the water and volatile compounds of chicken breast during the frying process

The influence of frying times (0, 2, 4, 6, 8, and 10 min) on the continuous changes in the water distribution and the concentrations of key volatile compounds in chicken breast during the frying process were studied. The fried chicken samples could be distinguished by PCA of E-nose and PLS-DA of GC-MS. A total of 40 volatile compounds were identified by GC-MS, and 28 compounds were verified to be the key compounds after further screening by OAVs. The T22 was increased first and then decreased, while the M22 and M23 in fried chicken were considerably decreased and increased with increasing frying time, respectively. The content of the water and the total peak area of LF-NMR in fried chicken samples during the frying process significantly decreased, and the water was transferred from high to low degrees of freedom. In addition, water content, T21, T22, M22 and L* value were positively correlated with most alcohols and aldehydes, and were negatively correlated with pyrazines, while a*, b*, M23 and all amino acids were positively correlated with pyrazines and were negatively correlated with most alcohols and aldehydes. The results may guide the production processes of fried chicken and help produce high-quality chicken products.

Isolation, characterization, and fermentation potential of coagulase-negative Staphylococci with taste-enhancing properties from Chinese traditional bacon

No proprietary starter cultures for crafting Chinese bacon. This study aimed to isolate Coagulase-negative Staphylococci (CNS) from Chinese bacon, identify their species, and evaluate their ability to produce biogenic amines (BAs), peptides, free amino acids (FAAs), and degrade proteins. Twenty-one isolates were deficient in hemolysis, DNase, and coagulase activities, and exhibited low amino acid decarboxylase activity. Further characterization revealed 11 CNS species showing protease, lipase, or nitrate reductase activities. Specifically, S. cohnii WX-M8 was able to degrade both sarcoplasmic and myofibrillar proteins, while S. saprophyticus MY-A10 was found to only degrade myofibrillar proteins. Both were able to reduce the BAs and increase the content of peptides around day 3. The meat fermented by these two CNS contained FAAs that are more conducive to taste formation, such as Glu and Asp, and reduced the content of bitter FAAs. These findings will provide insights into the use of CNS for Chinese bacon.

Effects of Fermentation with Tetragenococcus halophilus and Zygosaccharomyces rouxii on the Volatile Profiles of Soybean Protein Hydrolysates

The effects of fermentation with lactic acid bacteria (LAB) and yeast on the aroma of samples were analyzed in this work. The volatile features of different soybean hydrolysates were investigated using both GC-MS and GC-IMS. Only 47 volatile flavor compounds (VFCs) were detected when using GC-IMS, while a combination of GC-MS and GC-IMS resulted in the identification of 150 compounds. LAB-yeast fermentation could significantly increase the diversity and concentrations of VFCs (p < 0.05), including alcohols, acids, esters, and sulfurs, while reduce the contents of aldehydes and ketones. Hierarchical clustering and orthogonal partial least squares analyses confirmed the impact of fermentation on the VFCs of the hydrolysates. Seven compounds were identified as significant compounds distinguishing the aromas of different groups. The partial least squares regression analysis of the 25 key VFCs (ROAV > 1) and sensory results revealed that the treatment groups positively correlated with aromatic, caramel, sour, overall aroma, and most of the key VFCs. In summary, fermentation effectively reduced the fatty and bean-like flavors of soybean hydrolysates, enhancing the overall flavor quality, with sequential inoculation proving to be more effective than simultaneous inoculation. These findings provided a theoretical basis for improving and assessing the flavor of soybean protein hydrolysates.

Can Near-Infrared Spectroscopy Replace a Panel of Tasters in Sensory Analysis of Dry-Cured Bísaro Loin?

This study involved a comprehensive examination of sensory attributes in dry-cured Bísaro loins, including odor, androsterone, scatol, lean color, fat color, hardness, juiciness, chewiness, flavor intensity and flavor persistence. An analysis of 40 samples revealed a wide variation in these attributes, ensuring a robust margin for multivariate calibration purposes. The respective near-infrared (NIR) spectra unveiled distinct peaks associated with significant components, such as proteins, lipids and water. Support vector regression (SVR) models were methodically calibrated for all sensory attributes, with optimal results using multiplicative scattering correction pre-treatment, MinMax normalization and the radial base kernel (non-linear SVR model). This process involved partitioning the data into calibration (67%) and prediction (33%) subsets using the SPXY algorithm. The model parameters were optimized via a hybrid algorithm based on particle swarm optimization (PSO) to effectively minimize the root-mean-square error (RMSECV) derived from five-fold cross-validation and ensure the attainment of optimal model performance and predictive accuracy. The predictive models exhibited acceptable results, characterized by R-squared values close to 1 (0.9616-0.9955) and low RMSE values (0.0400-0.1031). The prediction set's relative standard deviation (RSD) remained under 5%. Comparisons with prior research revealed significant improvements in prediction accuracy, particularly when considering attributes like pig meat aroma, hardness, fat color and flavor intensity. This research underscores the potential of advanced analytical techniques to improve the precision of sensory evaluations in food quality assessment. Such advancements have the potential to benefit both the research community and the meat industry by closely aligning their practices with consumer preferences and expectations.

The contribution of inoculated probiotics to increased protein-derived volatile flavor compounds

This study aimed to evaluate the contribution and mechanisms of Lactobacillus plantarum and Zygosaccharomyces mellis inoculation to the enhancement of protein-derived volatile flavor compounds (PVFCs) in low-salt dry-cured mackerel (LDCM). The contents of PVFCs (3-methylbutanal and phenylacetaldehyde), intermediates (α-ketoisocaproate and phenylpyruvic acid), precursor (α-ketoisocaproate and phenylpyruvic acid), and key enzyme activities (protease and transaminase) significantly increased (p < 0.05) in probiotic-treated groups. The dominant species in the probiotics-treated groups were the inoculated Lactobacillus plantarum and Zygosaccharomyces mellis, which were the main producer of key enzymes for the generation of PVFCs. Lactobacillus plantarum performed well in protein degradation and amino acid transamination, resulting in generating more 3-methylbutanal and phenylacetaldehyde, while Zygosaccharomyces mellis played a main role in phenylethanol production. The synergistic action of Lactobacillus plantarum and Zygosaccharomyces mellis could promote the formation of 3-methyl-1-butanol.

Correlation Analysis between Volatile Compounds and Quality Attributes in Pork Tenderloin in Response to Different Stir-Frying Processes

Volatile compounds and physicochemical properties of meat are significantly changed by cooking processes. This study explored the influence of different stir-frying temperatures and times on the dynamic changes of the physicochemical characteristics and volatiles of pork tenderloin and determined the correlation between them. Results showed that time played more of a role than temperature. At the same temperature, the water content decreased (p < 0.05) and the cooking loss increased (p < 0.05) with stir-frying time extending. The L* value and the b* value showed first an increasing and then decreasing trend (p < 0.05), while the a* value significantly increased (p < 0.05). The higher the cooking temperature of sample, the faster the indexes changed. In stir-fried samples, 50 volatiles were identified. Correlation analysis showed that among the quality attributes, b* value and water content had the strongest impact on volatiles. The water content was negatively correlated with most of the compounds attributed to the desired aroma of stir-fried samples, while the correlation between the b* value and these volatiles was positive. Hence, changes in the types and contents of volatiles in stir-fried pork tenderloin could be predicted by detection of b* value and water content.

Study of Pansalt® or Laminaria Ochroleuca seaweed powder as potential NaCl replacers in dry-cured foal "cecina"

This study aimed to evaluate the effect of the total or partial replacement of NaCl by a commercial low-salt mixture Pansalt® (T1) or Kombu (L. ochroleuca) seaweed powder (T2), respectively, on the quality properties of dry-cured foal "cecina". Salt reformulation unaffected fat percentages, decreased (P < 0.001) moisture and ash contents, while protein amounts increased (P < 0.001) in the T2 batch. Considering the physicochemical variables, any significant differences were observed among batches, except for a*, water activity, and springiness values. T1 and T2 samples presented a significant (P < 0.001) sodium decrease of 39% and 48%, respectively, as well as, potassium and magnesium increase (P < 0.001). In addition, the seaweed improved (P < 0.001) calcium, iron, phosphorus, and zinc contents. All batches showed similar lipid profiles and the nutritional indices were in line with the health recommendations. NaCl replacement increased the proteolysis, causing the increment (P < 0.001) of the free amino acids total contents, especially in T2 samples. Changes were also detected in the aromatic profile of our samples, where lipid-derived compounds predominated in the CON batches, while substances originating from carbohydrate fermentation and amino acid breakdown were prevalent in reformulated samples, particularly in T2. In addition, the salting treatments did not affect the sensory profile, except for saltiness (T2). Hence, data indicated that the employ of these potential NaCl alternatives, in particular T2 formulation, represents a favorable approach to achieving equine "cecinas" with an enhanced mineral and healthier profile, without altering most of the sensorial properties.

Analysis of Nutritional Characteristics and Willingness to Pay of Consumers for Dry-Cured Sausages (Salchichón) Made with Textured Seed Oils

The consumption of processed meat products beyond recommended limits has been associated with serious health conditions, including heart disease, diabetes, and cancer. In an effort to create healthier options, the meat industry is exploring alternatives to animal fat in processed meats. This study focuses on replacing animal fat in dry-cured sausages (Salchichón) with textured chia, poppy, melon, and pumpkin oils. The research aims to evaluate the physical and nutritional changes resulting from this substitution and assess consumer acceptance through sensory analysis. The use of seed oils led to slight color changes and comparable texture, except for cohesiveness. The incorporation of textured seed oils resulted in reduced fat content, increased proportions of ashes and protein, and decreased energy value. The fatty acid composition showed lower proportions of saturated fatty acids and increased polyunsaturated fatty acids. Sensory analysis revealed that the control sample with pork fat received the highest ratings for appearance, texture, and taste, while samples with higher seed oil percentages scored lower due to color, cohesiveness, and specific flavors from the seed oils. Despite these variations, consumers demonstrated a high level of acceptability for all samples. Choice analysis results indicated that higher prices had a negative impact on consumer willingness to purchase, while the use of the 100% Iberian pig breed and animal welfare labels positively influenced purchasing attitudes. Regarding the presence of a pumpkin seed oil label in the product, a negative willingness to pay was reported. However, significant individual variation was reported for this attribute, indicating the existence of consumer segments with more positive attitudes toward these innovative dry-cured sausages.

Short-Term Changes in Aroma-Related Volatiles in Meat Model: Effect of Fat and D. hansenii Inoculation

This study assessed the effect of replacing pork lard with coconut oil and Debaryomyces hansenii inoculation on the biotransformation of amino acids into volatile compounds in a meat model system. Yeast counts, solid-phase microextraction, and gas chromatography/mass spectrometry were used to assess yeast growth and volatile production, respectively. Yeast growth was confirmed until 28 d, although the volatile profile changed until 39 d. Forty-three volatiles were quantified, and their odor activity values (OAVs) were calculated. The presence of fat and yeasts contributed to differences in volatiles. In pork lard models, a delayed formation of lipid-derived aldehyde compounds was observed, whereas in coconut oil models, the generation of acid compounds and their respective esters was enhanced. Yeast activity affected amino acid degradation, which produced an increase in branched-chain aldehydes and alcohols. The aroma profile in the coconut models was influenced by hexanal, acid compounds, and their respective esters, whereas in pork lard models, aroma was affected by methional (musty, potato) and 3-methylbutanal (green, cocoa). The yeast inoculation contributed to the generation of 3-methylbutanoic acid (cheesy) and phenylethyl alcohol (floral). The type of fat and yeast inoculation produced a differential effect on the aroma.

Analysis of physicochemical properties of dry-cured beef made from Hanwoo and Holstein meat distributed in South Korea

The purpose of the study is to check the possibility of developing dry-cured meat from Hanwoo (South Korean native cattle) and Holstein cattle considering the differences between breeds and use this data for the preparation and development of dry cured ham unique to South Korea. Same-grade Semitendinosus muscle from Hanwoo and Holstein was cured using a curing agent with 4.6% salt content at 4 °C for 7 days, and then aged for 70 days. Data was analyzed through physicochemical characterization, and the manufacturing period was established through weight loss, volatile basic nitrogen (VBN), thiobarbituric acid reactive substances (TBARS). Moisture content and weight loss of both samples significantly decreased during the manufacturing process (P < 0.05). TBARS was significantly higher in Hanwoo and VBN in Holstein (P < 0.05). According to the values of VBN (less than 20 mg/100 g) and TBARS (less than 2 mg MDA/kg), dry aging for 5 weeks is appropriate for both samples. The principal component analysis of 5 weeks-aged Holstein showed a dramatically changing trend due to myofibril fragmentation as indicated by Sodium dodecyl sulfate-polyacrylamide-gel electrophoresis. In addition, 5 weeks-aged Holstein contains methanethiol (cheese), butan-2-one (butter), and 3-3-ethyl-2-methyl-1,3-hexadiene (fatty acid-derive) compounds that represent fermentation and aging flavors. Therefore, the possibility of product development was confirmed by the 5-week aging of Holstein dry-cured ham.

Metabolome-Based Genome-Wide Association Study of Duck Meat Leads to Novel Genetic and Biochemical Insights

Meat is among the most consumed foods worldwide and has a unique flavor and high nutrient density in the human diet. However, the genetic and biochemical bases of meat nutrition and flavor are poorly understood. Here, 3431 metabolites and 702 volatiles in 423 skeletal muscle samples are profiled from a gradient consanguinity segregating population generated by Pekin duck × Liancheng duck crosses using metabolomic approaches. The authors identified 2862 metabolome-based genome-wide association studies (mGWAS) signals and 48 candidate genes potentially modulating metabolite and volatile levels, 79.2% of which are regulated by cis-regulatory elements. The level of plasmalogen is significantly associated with TMEM189 encoding plasmanylethanolamine desaturase 1. The levels of 2-pyrrolidone and glycerophospholipids are regulated by the gene expression of AOX1 and ACBD5, which further affects the levels of volatiles, 2-pyrrolidone and decanal, respectively. Genetic variations in GADL1 and CARNMT2 determine the levels of 49 metabolites including L-carnosine and anserine. This study provides novel insights into the genetic and biochemical basis of skeletal muscle metabolism and constitutes a valuable resource for the precise improvement of meat nutrition and flavor.

Effect of Seawater Curing Agent on the Flavor Profile of Dry-Cured Bacon Determined by Sensory Evaluation, Electronic Nose, and Fatty Composition Analysis

The purpose of this study was to check the applicability of seawater as a natural curing agent by analyzing the difference it causes in the flavor of dry-aged bacon. Pork belly was cured for seven days, and dried and aged for twenty-one days. The curing methods included the following: wet curing with salt in water, dry curing with sea salt, brine curing with brine solution, and bittern curing with bittern solution. The seawater-treated groups showed a lower volatile basic nitrogen value than the sea-salt-treated groups (p < 0.05); dry curing showed a higher thiobarbituric acid reactive substance value than other treatments (p < 0.05). Methyl- and butane- volatile compounds and polyunsaturated fatty acids such as g-linolenic and eicosapentaenoic were the highest in the bittern-cured group, lending it superior results compared to those of the control and other treatments in sensory flavor analyses (cheesy and milky). Therefore, bittern is considered to have significant potential as a food-curing agent.

Characteristic flavor fingerprint disclosure of dzo beef in Tibet by applying SAFE-GC-O-MS and HS-GC-IMS technology

To understand the overall flavor of the dzo beef, fatty acids, volatile compounds and aroma profiles of dzo beef samples (raw beef (RB), broth (BT) and cooked beef (CB)) were investigated by head-space-gas chromatography-ion mobility spectrometry (HS-GC-IMS) and gas chromatography-mass spectrometry (GC-MS). The fatty acid analysis showed a decrease in the ratio of polyunsaturated fatty acids, such as linoleic acid, which decreased from 2.60 % in RB to 0.51 % in CB. The principal component analysis (PCA) showed that HS-GC-IMS was able to distinguish different samples. A total of 19 characteristic compounds with odor activity value (OAV) > 1 were identified by gas chromatography-olfactometry (GC-O). Fruity, caramellic, fatty and fermented attributes were enhanced after stewing. Butyric acid and 4-methylphenol were responsible for the stronger off-odor in RB. 3-Hydroxy-2-butanone and 2,5-dimethyl-4-hydroxy-3(2H)-furanone with buttery and caramellic attributes were dominated in BT, while (E)-2-nonenal, (E,E)-2,4-decadienal and (E,E)-2,4-nonadienal prominently conferred fatty attribute on CB. Furthermore, anethole with anisic aroma was first identified in beef, which may be one of the typical chemical markers that distinguish dzo beef from other varieties.

Quality relationship between smoked and air-dried bacon of Sichuan-Chongqing in China: Free amino acids, volatile compounds, and microbial diversity

The quality formation of Chinese bacon is closely related to flavor compounds and microbial composition; however, the contribution of microbial to flavor has not been fully explored. Previous studies have focused on the differences in microorganisms and flavor substances in smoked bacon. Thus, this study aims to investigate the relationship among microorganisms, free amino acids (FAAs), and volatile compounds (VOCs) in bacon produced by different drying processes. We analyzed the microbial composition by sequencing the V3-V4 region of the 16S rDNA gene and the fungal ITS2 region and flavor substances using an amino acid analyzer and chromatography-mass spectrometry (GC-MS). Results of taste activity values (TVA) and partial least squares discriminant analysis (PLS-DA) revealed that the flavor components of the two types of bacon had general and specific characteristics, with the key FAAs (glutamic acid, lysine, and alanine) being comparable and the key VOCs being dissimilar. Based on non-metric multidimensional scaling (NMDS) and linear discriminant analysis effect size (LefSe), bacteria had more biomarkers than fungi. Correlation analysis demonstrated that microorganisms, particularly bacteria (Staphylococcus and Salinivibrio), are crucial in regulating and shaping the flavor of bacon. Some sub-abundance of bacteria such as Kocuria enrich the flavor of bacon. These findings indicate that the simultaneous fermentation of multiple microorganisms is conducive to the recreation of the artisan flavor of Chinese bacon.

Bifidobacterium animalis A12, a Probiotic Strain That Promotes Glucose and Lipid Metabolism, Improved the Texture and Aroma of the Fermented Sausage

Bifidobacterium animalis A12 was used for the development of fermented sausage. The growth activity, tolerance, and enzyme activity of B. animalis A12 and its contribution to the texture and flavour of fermented sausages were evaluated. Additionally, the sensory texture, flavour components, and amino acid nutrients during the fermentation process were assessed. B. animalis had high tolerance to NaCl and nitrite, and B. animalis A12 had protease and lipase activities. The pH value of sausage fermented with B. animalis A12 was lower than that of sausage fermented without any fermentation strain. Hexanal, heptanal, decanal, cis-2-decanal, and 4-methoxy-benzaldehyde are the unique aldehydes flavour components of fermented sausages in the A12 group. The highest content of volatile flavour substances and amino acids, and the color and texture characteristics of fermented sausage in the experimental group at 18 h were better than those at other times. These results suggest that B. animalis A12 has the potential to be used as a starter culture for im-proving flavour and texture in fermented sausage.

Analysis of flavor formation during the production of Jinhua dry-cured ham using headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS)

This study aimed to clarify the formation process of flavor compounds and identify the volatile substances present during a continuous period of Jinhua dry-cured ham (JDH) making. Via headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS), a total of 53 volatile organic compounds (VOCs), including 20 aldehydes, 16 alcohols, 11 ketones, 5 esters and 1 furan, were identified in JDH from seven sampling stages. The results showed that butanal, 3-methylbutanal, 2-methylbutanal, 2-hexanone, 2-pentanone and 2-butanone could be flavor markers in the evolution of aroma characteristics of JDH. Aldehydes (2-methylbutanal and 3-methylbutanal), alcohols (2-methylpropanol, 2-methylbutanol, 3-methylbutanol and 1-penten-3-ol), ketones (2-pentanone, 2-propanone, 2-butanone and 2-hexanone) and esters (ethyl acetate and ethyl 3-methylbutyrate) were considered the main VOCs in the mature JDH. Free fatty acid (FFA) analysis displayed the changes in intramuscular fat (IMF) of JDH. Additionally, principal component analysis (PCA) showed that drying-ripening was a critical stage in the flavor formation of JDH.

Effects of Starter Cultures and Type of Casings on the Microbial Features and Volatile Profile of Fermented Sausages

In the literature, the effect of the type of casing on fermented sausages is quite unexplored, while several studies are focused on the impact of starter cultures. Therefore, this paper studied the effect of three commercial starter cultures and two casings (natural or collagen) on Italian fermented sausages. Physico-chemical parameters (aw, pH, weight loss), microbiota, aroma profile and sensory analysis were evaluated. Results showed that collagen casings promoted a higher reduction of pH and weight loss. Concerning the microbiota, samples with natural casing had higher counts of lactic acid bacteria, while yeast proliferation was promoted in those with collagen. Regardless of the starters and casings applied, levels of enterococci and Enterobacteriaceae were low (≤2 log CFU/g). The aroma profile was significantly affected by casing: despite the starter applied, the presence of collagen casing favoured acid accumulation (mainly acetate and butanoate) and reduction of ketones. Sensory analysis highlighted significant differences only for odour, colour intensity and sourness. The differences observed suggest that collagen casings may provide a greater availability of oxygen. Overall, casings rather than starter cultures impact the microbial and sensorial features of fermented sausages.

Effects of Chitosan/Collagen Peptides/Cinnamon Bark Essential Oil Composite Coating on the Quality of Dry-Aged Beef

The aim of this study was to evaluate the effects of the chitosan/collagen peptides/cinnamon bark essential oil composite coating on dry-aged beef. Chitosan (2%, w/v), collagen peptides (1%, w/v), and cinnamon bark essential oil (1%, v/v) were homogenized to obtain the coating. Beef samples were divided into three groups (traditional dry-ageing, in-bag dry-ageing, and coating and then dry-ageing) and dry-aged for 42 days. Physiochemical, microbial, and sensorial parameters of samples were determined during the dry-ageing process. There were no significant differences (p > 0.05) in pH values, shear force values, cooking loss, color, juiciness, tenderness, and flavor across groups. The total volatile base nitrogen value of the coating group was lower than those of the other two groups. Compared to traditional dry-ageing, in-bag and coating dry-ageing reduced (p < 0.05) many volatile compounds such as alcohols, aldehydes, ketones, and acetate. In-bag and coating dry-ageing had no impact on the fungal community, but changed the bacterial community by inhibiting Pseudomonas. This study demonstrates that the chitosan/collagen peptides/cinnamon bark essential oil coating reduces microbial spoilage during dry-ageing, and has a small influence on product quality.

Plant Antioxidants in Dry Fermented Meat Products with a Healthier Lipid Profile

Consumers' perception of meat products has changed in recent years, which has led to an increased interest in healthier meat products. In response to this demand, academia and industry have made efforts to reformulate meat products, especially dry fermented meat products, which are known for their high fat contents, mainly saturated fat. The use of plant or marine oils stabilized in emulsion gels (EGs) or oil-bulking agents (OBAs) as animal fat replacers has been one of the most advantageous strategies to reformulate dry fermented meat products with a healthier lipid content (quality and quantity), but an increase in their polyunsaturated fatty acid content can trigger a significant increase in lipid oxidation, negatively affecting sensory and nutritional quality. The use of antioxidants is the main strategy to delay this deteriorative reaction, but the controversy around the safety and toxicity of synthetic antioxidants has driven consumers and industry toward the use of plant antioxidants, such as phenolic compounds, carotenoids, and some vitamins and minerals. This review provides information about the use of plant antioxidants to control lipid oxidation of dry fermented meat products with healthier lipids.

Evaluation of the Influence of Flavor Characteristics of Cooked Bacon with Different Sterilization Methods by GC-IMS Combined with HS-SPME-GC-MS and Electronic Nose

This study investigated the impact of high pressure and temperature (HTHP) and electron-beam irradiations (3, 5, 7, and 9 kGy) using differences in two sterilization methods on the volatile compounds and sensory characteristics of cooked bacon. It showed that 7 and 9 kGy of irradiation caused a significant reduction in species of volatile compounds and sensory features, but the concentration of total ketones, alcohols, aldehydes, acids and aromatic hydrocarbons significantly increased at 9 kGy. Samples treated with a dose of less than 5 kGy did not change volatile compounds and sensory properties. High-temperature-high-pressure conditions could greatly impact the concentrations of volatile compound species and sensory traits. The electronic nose effectively detected the flavor difference in different sterilization methods. Fingerprinting showed that HTHP and 9-kGy-treated groups were significantly different from other treatments. This study inferred that 5 kGy might be optimal for maintaining the original flavor and sensory properties of cooked bacon.