Differences in flavor characteristics of frozen surimi products reheated by microwave, water boiling, steaming, and frying

Effect of moisture equalization time on the quality of dried pre-tenderized shrimp: Texture, digestibility, and flavor characteristics

The aim of this study was to investigate the effect of moisture equalization time during drying process on the textural properties, in vitro digestibility and flavor characteristics of pre-tenderized shrimp. The results showed that adding a moisture equalization stage affected the tenderness and color brightness of dried shrimp and improved in vitro digestibility, evidenced by increased protein digestibility and free amino acid content. Furthermore, adding a moisture equalization stage could increase the rate of water reduction in dried shrimp during the subsequent drying process. Flavor analysis suggested that the composition of volatile compounds in shrimp changed after water equalization, and the content of alcohols and esters increased, resulting in a richer flavor of dried shrimp. This study concludes that adding a moisture equalization stage during drying improves the physicochemical characteristics and flavor quality of pre-tenderized dried shrimp.

Elucidation of formation and development of warmed-over flavor in precooked surimi products as affected by reheating methods

This study investigated reheating methods (water bath, WB; steam, SM; microwave, MW) on formation and development of undesired warmed-over flavor (WOF) in precooked surimi products. MW resulted in shrinkage of surimi gel, while SM caused large pores on disrupted structure. Unsaturated fatty acids, mainly oleic (308.15 mg/100 g) and linolenic acid (103.44 mg/100 g), were significantly higher in MW, followed by SM and WB (P < 0.05). Octanal, nonanal, decanal and 6 other odorants were major contributors to WOF of all reheated samples based on odor active values. MW contributed less to WOF formation, whereas SM induced generation of the largest variety of unpleasant odor-active substances, in which (E,E)-2,4-decadienal, 1-pentanethiol, 2-undecanone and (E)-2-octen-1-ol were uniquely found. Sensory evaluation verified the strongest WOF perception of SM. Odorant docking suggested the key WOF compounds could dock to three representative olfactory receptors. These findings provided guidance for flavor regulation of precooked surimi products.

Enhancing surimi gel properties in silver carp with innovative ultra-micro crayfish shell powder

This study investigated the preparation and application of ultra-micro crayfish shell powder to enhance the quality of surimi gels. A combination of ball milling and irradiation techniques produced an innovative powder (MID) with reduced particle size and enhanced zeta potential, dispersibility, Ca2+ release, and hydrogen bonding energy (p < 0.05), while maintaining its composition. Adding 0.50 % MID to surimi gels resulted in optimal improvements, enhancing gel strength and texture as well as elasticity. MID also increased the water holding capacity (WHC), decreased water mobility, and resulted in a dense and ordered microstructure. Fourier transform infrared spectroscopy indicated improvements were due to increased intermolecular non-covalent bonding interactions. Electronic nose analysis showed MID reduced aromatic compounds and organosulphides, preserving flavor and reducing the fishy taste. Electronic tongue analysis revealed an increase in fresh flavor response. The preparation method significantly enhanced the quality and sensory properties of surimi gels.

Comparative studies on microbial transglutaminase, complex phosphate and fructooligosaccharide interacts with myofibrillar proteins: Improvement of the quality and flavor of silver carp surimi

The aim of this study was to evaluate the effect of microbial transglutaminase (MTG), complex phosphate (CP) and fructooligosaccharide (FOS) interact with myofibrillar proteins (MPs) on the quality and flavor of silver carp surimi gels. When surimi was added with 0.3 % MTG, 0.3 % CP and 4 % FOS respectively, the gel strength and texture were superior to those of the control group, and the surimi microstructure became more compact with smaller pore sizes. This was because MTG can induce the ε-(γ-glutamate) lysine bond formation in surimi MPs and promotes cross-linking of MPs. CP can increase the ionic strength, FOS can form hydrogen bonds with water and enhance MPs hydration, both of them promoted the conversion of α-helix to β-folding of MPs, and facilitate the formation of disulfide bonds. 13 volatiles were identified in control group, whereas the number of volatiles was increased to 31, 22 and 22 after addition of MTG, CP and FOS respectively, suggesting that MTG, CP and FOS promoted lipid oxidation and interacted with MPs to produce volatile compounds. Therefore, the addition of MTG, CP and FOS improved the quality and flavor of chub surimi gels, with MTG having the greatest effect on surimi.

Analysis of Key Aroma Compound Changes in Grass Carp Fillets during Cold Storage Using Two-Dimensional Gas Chromatography-Olfactometry-Mass Spectrometry and Odor Activity Value

This study analyzed the changes in key aroma compounds in grass carp fillets during cold storage using aroma extract dilution analysis, odor activity values, and aroma recombination. A total of 11, 13, and 14 volatile compounds were recombined to construct recombination models representing the odor of fillets at 0, 3, and 7 days of cold storage, respectively. The key aroma compounds in fresh fillets included hexanal, (Z)-4-heptenal, nonanal, (E,E)-2,4-octadienal, (E,Z)-2,6-nonadienal, (E)-2-nonenal, decanal, (E)-2-decenal, (E,E)-2,4-decadienal, 1-octen-3-ol, and 2,3-pentanedione. Moreover, (E)-2-octenal, 2-cyclopenten-1-one, γ-dodecalactone, and octanoic acid became the key aroma compounds after 3 and 7 days of refrigeration, respectively. (Z)-4-Heptenal, (E,Z)-2,6-nonadienal, (E)-2-nonenal, decanal, and (E,E)-2,4-decadienal indicated the deterioration in flavor quality of fillets, which rose by 38.29 μg/kg (0-7 days). This study clarifies the key aroma compounds and characteristic compounds responsible for odor changes during the cold storage of fillets, establishing a basis for future improvement in odor quality during cold storage.

Influence of processing points on the flavor of meat balls braised with brown sauce

In this study, electronic nose, electronic tongue and solid-phase microextraction coupled with gas chromatography-olfactometry-mass spectrometry (SPME-GC-O-MS) were used to investigate the volatile flavor characteristics and the changing pattern of meat balls braised with brown sauce in prepared dishes during processing. A total of 13 volatile compounds were detected by combining the results of the OAVs and GC-O analyses using both methods. The detected volatile compounds were benzaldehyde, nonanal, (E)-2-octenal, citral, 6-methyl-5-hepten-2-one, 1-octen-3-ol, eucalyptol, linalool, ethyl acetate, eugenol, d-limonene, anethole, and estragole. Among them, 6-methyl-5-hepten-2-one showed importance in both GC-O and OAVs analyses and was the only significant volatile compounds in the processing of meat balls braised with brown sauce. The differences between the samples mainly stemmed from the different processing stages. Nonetheless, samples S5 and S6, which had similar volatile compounds, indicated that the difference between freezing and packaging resulted in a decrease in the quality of meat balls braised with brown sauce. Hence, the study could offer a theoretical foundation and technological assistance for enhancing the quality and flavor of mass-produced braised pork ball products.

Enhanced gel properties of low-salt (1 %) silver carp surimi via combined starch addition and 915 MHz microwave pasteurization treatment

The optimization of gel properties in low-salt surimi is critical for producing high-quality, health-oriented products. The objective of this study was to reveal the combined effects of starch addition and 915 MHz microwave pasteurization treatment on the low-salt (1 %) silver carp surimi gel properties. Surimi samples with and without starch were processed using either microwave pasteurization or water bath, and water bath processed surimi without starch served as the control. Gel strength, texture, water-holding capacity (WHC), whiteness, water molecules distribution and mobility, protein secondary structure, and gel network were used to assess the gel properties and microstructure of the samples. Results demonstrated that microwave treatment and starch addition each improved gel properties, while their combination yielded the most significant enhancements. For surimi with starch treated by microwave, the gel strength increased by 93.50 % (406.93 g·cm to 787.42 g·cm), and WHC rose from 0.72 to 0.91, compared to controls. Additionally, this combination promoted ordered protein structure formation, which was characterized by increased β-sheet content to 60.92 % and decreased α-helix content to 10.74 %. These results indicated that microwave treatment and starch have a synergistic effect on improving the surimi gel properties. The alternative electric fields and faster heating rate of microwaves enhanced the starch-protein cross-linking and interaction forces, which contributed to the formation of a more compact and uniform microstructure. These results provided practical data for producing high-quality, low-salt surimi products.

Surimi and Low-Salt Surimi Gelation: Key Components to Enhance the Physicochemical Properties of Gels

Surimi-based products are nutritionally valuable due to their essential amino acid composition, their content of high-quality proteins with excellent digestibility, and their low fat content. However, to achieve the desired texture, a significant amount of salt (1-3%) must be added, which could compromise their health benefits. This study provides an overview of surimi production, the gelation mechanism of myosin, and the most relevant gelation enhancers that could be used in manufacturing low-salt surimi-based products. Reducing the salt content in surimi-based products presents a significant challenge for the industry, not only from technological and sensory perspectives but also in response to the growing demand of consumers for healthier food options. So, this manuscript highlights several strategies for achieving optimal quality characteristics in relation to functional properties for the surimi products industry. In addition, surimi as a raw material is often misunderstood by consumers, who may question its nutritional value and, consequently, its consumption. Therefore, it is crucial to thoroughly explain the processing of this raw material and emphasize the importance of proper myofibrillar protein gelation to develop high-value surimi-based products.

Insight into the mechanism of gel properties, microstructure and flavor of surimi gels improved by wheat bran with different particle sizes

This study investigated the effect of wheat bran (WB) with different particle sizes (W1, 155.00 ± 2.08 μm; W2, 78.33 ± 0.52 μm; W3, 46.90 ± 0.60 μm; W4, 23.53 ± 0.49 μm; and W5, 12.97 ± 0.19 μm) on the gel strength, texture, microstructure, dynamic rheological, secondary structures and flavor of surimi gels. Results demonstrated that the gel strength and water-holding capacity (WHC) of the surimi gels gradually increased with the decrease in WB particle size. The added W5 (12.97 ± 0.19 μm) increased the bound water content in the surimi gels by 12.60 % whereas the free water decreased by 6.59 % (p < 0.05), indicating that the addition of superfine WB contributed to the conversion of free water into bound water in the surimi gels matrices. Microstructural observations indicated that WB with different particle sizes promoted the formation of a continuous gel matrix and a denser surimi gel network structure. The β-sheet dominated in the secondary structure of surimi gels. Electronic tongue results showed that the addition of WB reduced the bitterness of surimi gels. Gas chromatography-ion mobility spectrometry (GC-IMS) results revealed that more esters were present in the samples when W1, W2, and W3 were added. Overall, W5 had the best enhancement effect on the quality of surimi gels, and this study lays the reference value for WB as an agricultural by-product to improve the quality of surimi products.

Effect of epigallocatechin gallate/transglutaminase synergistic cross-linking on the flavor of surimi gels

Epigallocatechin gallate (EGCG) and transglutaminase (TGase) can improve the structure of surimi gels, and have a significant impact on their texture and flavor quality. The formation and release of volatile odors due to EGCG, TGase and EGCG/TGase synergistic cross-linking of surimi gels were investigated. The characteristic flavor components of the surimi gels were aldehydes. Compared with the blank group, the total content of volatile compounds in EGCG, TGase, and EGCG/TGase groups decreased by 14.43, 11.69, and 20.07 %, indicating that the flavor of EGCG/TGase group was more affected by EGCG than by TGase. The free fatty acid content in these groups decreased by 17.28, 1.30, and 43.98 mg/100 g, indicating that the degree of fatty acid degradation in the EGCG/TGase group was lower during a two-stage heating process, which may be ascribed to EGCG's inhibition of oxidative degradation of fatty acids, thereby reducing the production of flavor substances.

Evaluating the effects of different preheating and reheating procedures on water-holding capacity and flavor in meat patties

The choice of processing technology for prepared meat products is at the core of the quality of the product, especially the appropriate preheating temperatures and reheating methods. This study investigated the effects of preheating and reheating processes on the water-holding capacity and flavor of prepared meat patties. The results indicated that the water-holding capacity of the heating-up preheating type was superior to that of the other preheating types. The product yield of the 160 → 190 °C preheating group was the highest (96.12 %), with the lowest reheating loss (11.32 %) and the largest proportion of immobilized water. Moreover, the GC-IMS analysis further revealed that the 160 → 190 °C preheating group had lower butyric acid contents and higher amounts of 2-acetylfuran and ethyl acetate, which conferred a sweet nutty aroma and fruity flavors to the patties. Among the five reheating groups, the electronic nose and GC-IMS comprehensively revealed that the flavor profile of the air-frying group had an attractive flavor characteristic. Additionally, more pyrazines and sulfur-containing compounds with pleasant odors were identified in the air-frying group. Furthermore, the air-frying reheated prepared meat patties scored the highest in sensory tests, with the highest purchase intention (80 %), and the purchase intention of the boiling group was only 20 %. This study is expected to improve the traditional process and provide a new strategy for developing high-quality meat products.

Evaluating the impact of different processing methods on the flavor characteristics of Gorgon Euryale seeds using electronic tongue, electronic nose, gas chromatography-mass spectrometry, and gas chromatography-ion mobility spectrometry

This study evaluated the volatile organic compounds (VOCs) and taste properties of Gorgon Euryale seeds processed by five methods (steaming, boiling, microwaving, roasting, and stir-frying) using electronic tongue (E-tongue), electronic nose (E-nose), gas chromatography-mass spectrometry (GC-MS), and gas chromatography-ion mobility spectrometry (GC-IMS). A total of 44 and 40 VOCs were identified by GC-MS and GC-IMS, respectively. Pyrazines (2-ethyl-3,5-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine) and furans (2-pentylfuran, 2-ethylfuran) played a major role in the baked aroma characteristics of roasted and stir-fried Gorgon Euryale seeds. Six and seven marker compounds were identified by Orthogonal Partial Least Square Discriminant Analysis (OPLS-DA) models for GC-MS and GC-IMS based on 12 VOCs with odor activity value > 1 and 18 VOCs with relative odor activity value > 0.1, respectively. OPLS-DA and principal component analysis score plots of the E-tongue and E-nose demonstrated that samples could be effectively distinguished in terms of flavor. This research provides a comprehensive basis for evaluating the impact of processing methods on the changes in flavor of Gorgon Euryale seeds. PRACTICAL APPLICATION: This work demonstrates that the use of E-tongue, E-nose, HS-SPME-GC-MS, and GC-IMS has the capability to thoroughly analyze the flavor profile of Gorgon Euryale seeds at both macro and micro levels. This approach effectively distinguishes Gorgon Euryale products subjected to different processing treatments and provides a reliable reference for evaluating and identifying the flavor quality of Gorgon Euryale seeds.

Substitution of NaCl by organic sodium salts in cured large yellow croaker (Larimichthys crocea): Improvement of the quality and flavor characteristic

For lowering the daily intake of salt, the study evaluated the impact of various organic sodium salts (OSS), including sodium acetate (SA), sodium citrate (SC), and sodium lactate (SL), on the quality and volatile flavor profiles of large yellow croaker. The results showed that the 5 % SC and 5 % SL treatments significantly improved water holding capacity (WHC), texture, and color (p < 0.05). These groups also demonstrated compact microstructures and maintained strong sensory acceptability. However, as the curing concentration increased, protein unfolding and oxidation intensified, and the transition from bound and immobile water to free water was observed. This shift negatively affected WHC, texture, and cell structure. Additionally, gas chromatography-ion mobility spectrometry (GC-IMS) identified 27 volatile compounds, with OSS treatments notably enhancing flavor intensity. These findings offer valuable insights for developing low-sodium practices in the seafood industry.

Comparative analysis of quality and flavor profiles in raw and pre-cooked large yellow croaker (Larimichthys crocea) meat post freezing and reheating

To clarify the potential application of large yellow croaker (LYC) as a prefabricated dish, present study evaluated the quality and flavor differences between raw and pre-cooked LYC after freezing storage and reheating via steam, water bath, and microwave methods. Results showed that raw meat retained significantly higher moisture content and water-holding capacity (WHC) compared to pre-cooked meat (p < 0.05). At 0 weeks, moisture content in RA-W, RA-S, and RA-M was 1.25 %, 2.06 %, and 3.2 % higher than PC-W, PC-S, and PC-M, respectively. WHC of RA-W, RA-S, and RA-M was 1.85 %, 4.1 %, and 1.01 % higher than raw group. Pre-cooked samples had significantly higher lipid and protein oxidation, especially with microwave reheating, with TBARS 27.5 % higher than raw group. Sensory scores and color stability were better maintained in pre-cooked samples. GC-IMS indicated that volatile flavor peak intensities were highest in the microwave group. The study provides insights for developing prefabricated LYC dishes.

Reheating-induced gel properties change and flavor evolution of surimi-based seafood: Effects and mechanisms

This study investigated the effect of different reheating treatments on gel properties and flavor changes of surimi products. As the reheating temperature increased from 90 °C to 121 °C, the heat-induced proteolysis produced more abundant umami and sweet amino acids, which took part in the conversion of IMP to AMP, thus enhancing the taste profiles. Reheating increased the exposure of active -NH2 terminals in proteins, which boosted Maillard and Strecker reactions with carbonyl compounds originated from fatty acid oxidation, thus not only reducing the aldehydes and esters contents but also lowering the whiteness of surimi products. Reheating at 90 °C prohibited the production of warmed-over flavor (WOF) and well-preserved the textural characteristics, but high temperatures ≥100 °C were prone to generate furan as the major WOF substance and to destroy gel structures. Collectively, this study provides new insights on understanding the role of reheating on sensory properties of surimi products.

Effect of refrigeration and reheating on the lipid oxidation and volatile compounds in silver carp surimi gels

BACKGROUND

As unsaturated and saturated aldehydes, ketones are known to be responsible for off-odors in surimi products, and they are mainly derived from lipid oxidation. Because surimi-based products are rich in unsaturated fatty acids, they are prone to producing off-odors during the refrigeration and reheating processes, which are common treatments for leftovers. The present study investigated the color, lipid oxidation productions, fatty acid profiles and volatile components in surimi gels during refrigeration at 4 °C for 3 days with multiple reheating.

RESULTS

The results revealed that the accumulation rate of hydroperoxides was higher in the refrigeration stage, whereas the decomposition rate was higher during reheating in surimi gels. Both refrigeration and reheating treatments promoted conjugated diene values, acid values and carbonyl values. Nevertheless, reheating treatment decreased tohiobarbituric acid reactive substances and whiteness. The contents of unsaturated fatty acids, especially α-linolenic acid, arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid, were reduced, whereas the contents of saturated fatty acids increased during refrigeration and multiple reheating. The unsaturated fatty acids were lost as a result of their oxidative deterioration. The volatile components profile showed that the accumulation of volatile components mainly occurred in the refrigeration stage. Multivariate data analysis was utilized to further clarify whether the off-odors in surimi gels were mainly generated in refrigeration.

CONCLUSION

Refrigeration and reheating both contributed to lipid oxidation and the generation of volatile compounds in surimi gels, but the off-odors were mainly generated during refrigeration. This research provides a novel understanding of the formation of food odors in processing. © 2024 Society of Chemical Industry.

The flavor enhancement mechanism of ultrasound-assisted curing and UV-assisted drying in semi-dried tilapia fillets based on flavoromics, lipidomics, and metabolomics

This study aimed to investigate the effects of ultrasound-assisted curing and UV-assisted drying on the quality of semi-dried tilapia fillets through flavoromics, lipidomics, and metabolomics. Both treatments enhanced myofibril pore space and reduced moisture content (-14.84 %, P < 0.05), with ultrasound demonstrating greater effectiveness. Additionally, they also facilitated lipid oxidation (P < 0.05), which altered the flavor profile. UV treatment enhancing key aroma compounds (ROAV >1), especially octanal, 1-octen-3-one, ethyl-isovalerate, and 2-pentyl-furan, more effectively than ultrasound (P < 0.05). 420 lipid molecules and 213 metabolites were identified, including 162 differential lipids and 69 differential metabolites (VIP > 1). Correlation analysis indicated that triglycerides, fatty acids, organic acids, and nucleosides were key precursors of flavor. The sensory evaluation demonstrated that ultrasound and UV treatments synergistically enhanced fillet quality. This study introduces an innovative processing method aimed at the industrialized and efficient production of high-quality air-dried aquatic products.

The Effects of Cooking Methods on Gel Properties, Lipid Quality, and Flavor of Surimi Gels Fortified with Antarctic Krill (Euphausia superba) Oil as High Internal Phase Emulsions

In this study, silver carp surimi products enriched with Antarctic krill oil high internal phase emulsions (AKO-HIPEs) were cooked using steaming (STE), microwave heating (MIC), and air-frying (AIR), respectively. The gel and flavor properties, lipid quality and stability were investigated. Compared to the MIC and AIR groups, the STE surimi gel added with HIPEs had better texture properties, exhibiting higher water-holding capacity and a more homogeneous structure, while the air-frying treatment resulted in visually brighter surimi products. The degree of lipid oxidation during cooking was in an order of STE < MIC < AIR as determined by electron paramagnetic resonance spectrometer and thiobarbituric acid reactive substances. HIPE-added surimi gels retained more nutrients and flavor when cooked by AIR compared to STE and MIC. Results imply that the texture properties and lipid stability of surimi products fortified with AKO-HIPEs were better than those of the oil group under any cooking method. In conclusion, surimi products added with AKO-HIPEs had better gel properties and retained more fatty acids and flavor than AKO-SO.

Kinetics and mechanisms of thermal deterioration in silver carp (Hypophthalmichtys molitrix) surimi gel quality under high-temperature sterilization

BACKGROUND

The gelation properties of surimi gel under various high temperatures (115, 118, and 121 °C) and sterilization intensities (F0 values of 3-7 min) were systematically investigated. A kinetic model detailed quality changes during heat treatment through mathematical analysis, elucidating mechanisms for gel quality degradation.

RESULTS

Increased sterilization intensity significantly reduced the quality characteristics of surimi gel. Compared to the gel without sterilization treatment, when the sterilization intensity was increased to 7 min, the gel strength of the groups treated at 115 °C, 118 °C, and 121 °C decreased by 68.35%, 51.4%, and 51.71%, respectively, and the water-holding capacity decreased by 24.87%, 16.85%, and 22.5%, respectively. The hardness, chewiness, and whiteness of the gel also significantly decreased, and the changes in these indicators all conformed to a first-order kinetic model. Activation energy of 291.52 kJ mol-1 highlighted gel strength as the least heat-resistant. At equivalent sterilization intensities, 115 °C exhibited the poorest gel quality, followed by 121 °C, with 118 °C showing relatively better gel quality. Increased T22 and decreased PT22 suggested heightened water mobility and transition of immobilized water within the gel into free water. Protein degradation, weakened disulfide bonds and hydrophobic interaction, and protein conformation changes collectively led to a rough and incoherent gel network structure with large fissures, as verified by the results of scanning electron microscopy. Correlation analysis indicated potential for precise control over surimi gel quality by modulating physicochemical attributes.

CONCLUSION

The outcomes may be beneficial to improve the production and quality control of ready-to-eat surimi-based products. © 2024 Society of Chemical Industry.

Different stages of flavor variations among canned Antarctic krill (Euphausia superba): Based on GC-IMS and PLS-DA

The aim of the present study was to explore changes in the profile of volatile compounds (VCs) in canned Antarctic krill (Euphausia superba) at different processing stages using partial least squares discriminant analysis (PLS-DA) and gas chromatography-mass spectrometry (GC-IMS). A total of 43 VCs were detected using GC-IMS in all krill meat samples, which included mainly alcohols, aldehydes, ketones, esters, and furans. Considering the different processing stages, the highest variation in VCs and the highest VC content were observed in krill meat which underwent both blanching and salt addition. PLS-DA further revealed flavor differences in canned Antarctic krill meat at different processing stages, with octanal, 2-hexanol, 2-octane, 2,3,5-trimethyl pyrazine, and cis-3-hexanol as the main contributors to observed differences in VC profiles. These findings contribute to the production of high-quality canned krill meat, enhancing its flavor quality and providing a feasible theoretical basis for future krill meat pretreatment and industry development.

Insight into the role of lipids in odor changes of frozen grass carp (Ctenopharyngodon idella) based on lipidomics and GC-MS analysis: Impact of freeze-thaw cycles and heat treatment

The role of lipids in changes of volatile organic compounds (VOCs) in grass carp during 1 month of frozen storage with different freeze-thaw cycles and subsequent heat treatment was investigated. Sixty VOCs were identified in all groups by SPME-GC-MS. Odor contents fluctuated along with the freeze-thaw cycles and heat treatment, and the highest odor content was observed in frozen sample without freeze-thaw cycles. Freeze-thaw and heat treatment significantly promoted the lipid oxidation and hydrolysis for all the groups(p<0.05). Lipid metabolites were analyzed using non-targeted lipidomics and could be well distinguished among different freeze-thaw groups and heat-treatment groups. A total of 10 key differential lipid molecules were annotated, involving 4 metabolic pathways related to lipid degradation and odor formation. Spearman correlation analysis showed that these key differential lipids were significantly related to the formation of key VOCs (p<0.05).

Combination of contact ultrasound and infrared radiation for improving the quality and flavor of air-dried beef during hot air drying

Air-dried beef, a traditional dry fermented meat product in China, whose quality is largely influenced by processing conditions. In this study, contact ultrasound (CU) and infrared radiation (IR) were employed to enhance hot air drying (HAD), with an investigation into the mechanisms underlying improvements in quality and flavor. Samples subjected to CU and IR treatments during HAD (CU-IRD) demonstrated superior color (L* = 42.68, a* = 5.05, b* = -3.86) and tenderness (140.59 N) than HAD group, primarily attributed to reduced drying times and alterations in ultrastructure. Analyses utilizing SDS-PAGE and total volatile basic nitrogen (TVB-N) revealed that HAD and CU-HAD resulted in significant protein oxidation (197.85 mg TVB-N/kg and 202.23 mg TVB-N/kg, respectively), while IR treatments were associated with increased thermal degradation of proteins, producing lower molecular weight peptides. Compared with HAD group, the activities of certain lipases and proteases were enhanced by ultrasound and infrared treatments, leading to the release of greater amounts of free fatty acids and flavor amino acids. Furthermore, the thermal effects of infrared and the cavitation effects of ultrasound contributed to increased fat oxidation, amino acid Strecker degradation, and esterification reactions, thereby augmenting the diversity and concentration of volatile flavor compounds, including alkanes, ketones, aldehydes, and esters. These findings indicate that the synergistic application of CU and IR represents a promising strategy for enhancing the quality of air-dried beef.

Identification of characteristic flavor quality of ceramic-pot sealed meat after reheating based on HS-GC-IMS, bionic sensory combined chemometrics

This study investigated the impacts of microwave reheating (MR), boil reheating (BR), and steam reheating (SR) on the flavor profile of Ceramic-Pot Sealed Meat (CPSM). Electronic nose and tongue revealed that the microwaving was superior in preserving the original olfactory and gustatory profiles of CPSM compared to the other methods. Headspace- Gas chromatography- ion mobility spectrometry (HS-GC-IMS) detected 48 compounds, encompassing 15 alcohols, 11 aldehydes, 9 ketones, 7 esters, 2 alkenes, and 2 others, 1 acid. Spectral and clustering analysis revealed a significant rise in the content of Warmed-over flavor compounds after boil reheating, culminating in pronounced flavor distortion and a decline in sensory scores. Relative odor activity value (ROAV) and chemometrics identified nine substances as the principal flavor compounds responsible to flavor distortion. In conclusion, all reheating methods induce changes in the original flavor characteristics profiles of CPSM. However, microwave reheating offers superior preservation of the flavor characteristics of CPSM.

Exploring the influence and mechanism of different frying methods on the flavor quality of low-salt sour meat

To obtain nutritious, healthy, and flavor-enriched sour meat products, the effects of different frying methods (microwave, air-frying, and traditional frying) on the flavor quality of low-salt sour meat were evaluated using metabolomics and other flavor analysis techniques. The pH value of the sour meat rose dramatically, while the TBARS value dropped significantly after frying. E-nose and E-tongue results showed that air-frying could reduce acidity and improve umami. The comprehensive analysis of all samples revealed the identification of 107 volatile flavor compounds, including 10 unique aroma compounds that were specifically detected in the AF group. Additionally, the air frying process notably increased the free amino acid and nucleotide concentrations in sour meat by 53.58% and 159.29%, respectively, while causing a significant reduction in both fatty acid and lactic acid content by 22.84% and 49.29%, respectively. All three frying methods altered the flavor of the samples, but air frying performed better in terms of flavor and texture.

κ-Carrageenan masking bitterness perception in surimi gels containing potassium chloride-based salt substitutes: Gel properties, oral processing, and sensory evaluation

κ-Carrageenan (CG) was employed to mask the bitterness induced by 50% KCl in surimi gels to achieve salt reduction and gel performance improvement. The combination of KCl and CG (KCl + CG) yielded the increased textural characteristics and water-holding capacity (WHC) of surimi gels and facilitated the transition of free water to immobilized water. In addition, the KCl + CG supplement increased the turbidity and particle size of myofibrillar protein (MP) sols but decreased the surface hydrophobicity in a dose-dependent manner. The hydrophobic interactions and disulfide bonds played crucial roles in maintaining the stability of MP gels. The specific binding of potassium ions to the sulfate groups of CG limited the release and diffusion of potassium ions from the surimi gels during oral processing, effectively masking the bitterness perception and maintaining the saltiness perception. This study provides a promising strategy to reduce the utilization of sodium salt in surimi products.

Ready-to-Cook Foods: Technological Developments and Future Trends-A Systematic Review

Ready-to-cook (RTC) foods can significantly improve the cooking experience of busy or unskillful consumers, based on production involving technical combinations of food processing and packaging. Initialized by a market survey of 172 products in Beijing, this systematic review analyzes RTC foods' development status according to ingredients, packaging, and storage conditions to further clarify the scope of RTC foods. The working principles and efficacy of various food processing techniques, such as washing, cutting, marinating, and frying, and packaging design or innovations such as modified atmosphere packaging (MAP) were both summarized in detail, with attention to their ability to extend shelf life, reduce safety risks, and maximize production efficiency in RTC food production. The cutting-edge technologies that may potentially apply in the RTC food processing or packaging sector were compared with current approaches to visualize the direction of future developments. In conclusion, we have observed the specific pattern of RTC food varieties and packaging formats in the Beijing market and revealed the advancements in RTC food technologies that will continue playing a critical role in shaping this growing market, while challenges in scalability, cost-efficiency, and sustainability remain key areas for future research. The data and perspectives presented will articulate the conceptions and existing challenges of RTC food, foster consumer perception and recognition of similar products, and deliver useful guidance for stakeholders interested in such products.

Effects of Steaming on Chemical Composition of Different Varieties of Purple-Fleshed Sweetpotato

Purple-fleshed sweetpotatoes (PFSPs) are rich in anthocyanins and are one of the health foods of interest. In this study, the effects of steaming on the anthocyanin, starch, soluble sugar, volatile organic compounds (VOCs) and pasting properties of nine PFSPs from China were investigated. The anthocyanin content of raw PFSP ranged from 9 to 185 mg/100 g. The total starch content decreased and soluble sugar content increased in all purple potatoes after steaming. Among the nine PFSPs varieties, Guangshu20 showed the greatest decrease in starch content (30.61%) and the greatest increase in soluble sugar content (31.12%). The pasting properties affected the taste of the PFSPs, with Shuangpihuang having the lowest peak viscosity (720.33 cP) and Guangzishu12 having the highest peak viscosity (2501.67 cP). Correlation studies showed that the anthocyanin content and pasting properties were negatively correlated with most of the sensory indicators, whereas the soluble sugar content of steamed PFSPs was significantly positively correlated with sweetness. A total of 54 VOCs were identified in this study, and aldehydes and terpenoids were the major VOCs in PFSPs. This study provides a theoretical basis for the processing of different PFSP varieties.

The impacts of cold plasma on the taste and odor formation of dried silver carp products

This study investigated non-thermal pretreatment (cold plasma, CP) on the flavor (taste and odor) profiles of dried fish products. CP treatment of 5 min contributed to accumulation of umami nucleotides adenosine 5'-monophosphate (AMP) from 30.96 to 40.82 μg/g and inosine 5'-monophosphate (IMP) from 2009.29 to 2132.23 μg/g, and significant reduction of bitter hypoxanthine ribonucleoside (HxR) and hypoxanthine (Hx), respectively (P < 0.05) in the dried fish products. A noticeable enhancement in sweet glycine (from 429.41 to 490.03 mg/100 g) and umami glutamic acid (from 55.68 to 67.76 mg/100 g) accompanied with the CP treatment (P < 0.05) based on taste activity value (TAV > 1). And the characteristic odor volatiles (nonanal, hexanal and 1-octen-3-ol) were strengthened 2.13-, 2.16- and 2.17- folds, respectively (P < 0.05). The results of equivalent umami concentration and Gibbs free energy calculation, combining with the correlation analysis, indicate that nucleotides and free amino acids synergically enhanced the taste improvement of dried fish products. Moderate lipids oxidation favored the formation of characteristic volatiles. The CP pretreatment offered new strategies for enhancing flavor of dried fish products.

Analysis of volatile flavor compounds in Antarctic krill paste with different processing methods based on GC-IMS

In this study, shrimp paste was prepared using Antarctic krill and fermented Antarctic krill shrimp paste as raw materials. Two commonly used heating methods, stir-fried and steaming, were analyzed, the main difference between the two methods being that stir-frying involves putting the shrimp paste into a wok and stir-frying it for different periods of time, while steaming involves putting the shrimp paste into a steamer and steaming it for different periods of time. The effects of different salt concentrations and processing techniques on the volatile flavor compounds of shrimp paste were also observed. Electronic nose and gas chromatography-ion mobility spectrometry (GC-IMS) were employed to analyze the volatile flavor compounds. A total of 52 volatile flavor compounds were detected by GC-IMS, of which 38 were identified (including monomers, dimers, and polymers). The identified compounds included 11 aldehydes, 6 ketones, 14 alcohols, 2 esters, 2 acids, 1 pyridine compound, and 2 sulfur compounds. In addition, 14 compounds were identifiable. Using the results of the electronic nose analysis, we were also able to differentiate between the volatile flavor compounds in shrimp pastes produced by different processing methods.

Perilla juice and ginger juice reduced warmed-over flavor (WOF) in surimi gels: Due to the inhibition of the formation of the WOF compounds and the masking of the WOF

The effects and reasons of perilla juice (PJ) and ginger juice (GJ) on the reduction of "warmed-over flavor" (WOF) in surimi gels were revealed by detecting odor profiles and protein and lipid oxidation degrees of surimi gels, concentrations and odor activity values (OAVs) of WOF compounds. Adding PJ and GJ to surimi gels significantly reduced the WOF and improved the fish fragrance odor, but sodium ascorbate (SA) only weakened the WOF. The (E,E)-2,4-heptadienal's OAVs in the PJ and GJ groups were decreased by >50% compared with the control check (CK) and SA groups. Meanwhile, surimi gels added with PJ and GJ presented lower lipid and protein oxidation degrees. The verification test indicated that PJ and GJ's aroma had a masking effect on the WOF. In conclusion, PJ and GJ reduced the WOF in surimi gels by preventing WOF compounds' production and masking the WOF with their distinct aroma.

Performance and protein conformation of thermally treated silver carp (Hypophthalmichthys molitrix) and scallop (Argopecten irradians) blended gels

BACKGROUND

The quality of surimi-based products can be improved by combining the flesh of different aquatic organisms. The present study investigated the effects of incorporating diverse ratios of unwashed silver carp (H) and scallop (A) and using various thermal treatments on the moisture, texture, microstructure, and conformation of the blended gels and myofibrillar protein of surimi.

RESULTS

A mixture ratio of A:H = 1:3 yielded the highest gel strength, which was 60.4% higher than that of scallop gel. The cooking losses of high-pressure heating and water-bath microwaving were significantly higher than those of other methods (P < 0.05). Moreover, the two-step water bath and water-bath microwaving samples exhibited a more regular spatial network structure compared to other samples. The mixed samples exhibited a microstructure with a uniform and ordered spatial network, allowing more free water to be trapped by the internal structure, resulting in more favorable gel properties. The thermal treatments comprehensively modified the tertiary and quaternary structures of proteins in unwashed mixed gel promoted protein unfurling, provided more hydrophobic interactions, enhanced protein aggregation and improved the gel performance.

CONCLUSION

The findings of the present study improve our understanding of the interactions between proteins from different sources. We propose a new method for modifying surimi's gel properties, facilitating the development of mixed surimi products, as well as enhancing the efficient utilization of aquatic resources. © 2024 Society of Chemical Industry.

Effect of ozone oxidation on gastrointestinal digestion and absorption characteristics of silver carp (Hypophthalmichthys molitrix) surimi gels in vitro

To investigate the quality of different ozone-oxidized surimi gels and their in vitro digestion and absorption characteristics, surimi rinsed with different concentrations of ozonated water (0, 8, 26 mg/L) were prepared. Then, the degree of oxidation and gel structure of surimi were determined, the in vitro digestion and absorption of the gels were simulated, and the digestion and absorption products were analyzed by LC-MS/MS. The results showed that the quality of surimi gels was improved after proper ozone oxidation. After ozone water rinsing, the dry matter digestibility, peptide, and amino acid content increased, and the changes of all three were in line with the Logistic kinetic model (R2 = 0.95-0.99). Caco-2 cell absorption experiments showed that the absorption rate of peptides and amino acids decreased after ozone water rinsing. In summary, ozone oxidation can promote the digestion of surimi gels, but it also reduces the absorption of peptides and amino acids by Caco-2 cells. This study provides a reference for the application of ozone in the food field.

Yeast extracts weakened warmed-over flavor in surimi gels made from silver carp due to the masking effect by high concentrations of pyrazines and esters

Warmed-over flavor (WOF) is an off-flavor in surimi gels. Yeast extract (YE) could improve the aroma properties of food. However, the effect of YE on the WOF in surimi gels and its mechanism was still unclear. In this study, aroma profiles, the composition of aroma compounds and aroma precursors, concentrations of WOF compounds, and thiobarbituric acid reactive substances (TBARS) of surimi gels with different amounts of YE were investigated by molecular sensory science and chromatographic techniques. Moreover, the effect of pyrazines and esters introduced by YE on WOF was also tested by sensory analysis. The addition of no less than 1% YE to surimi gels significantly weakened WOF. However, YE did not decrease the concentrations of WOF compounds and did not change the fatty acid composition and TBARS in surimi gels. Conversely, the addition of YE significantly increased the contents of free amino acids, N-containing compounds, and esters in surimi gels. The contents of total free amino acids, 2,6-dimethylpyrazine, and ethyl acetate in surimi gels with 2.5% YE were 1.5, 21, and 2.1 times higher than those in the control, respectively. Additionally, the sensory results of the spiked aroma models containing WOF compounds, 2,6-dimethylpyrazine, and esters showed that more than 9.4 µg/kg of 2,6-dimethylpyrazine with a baked-potato note and more than 6.1 µg/kg of ethyl acetate and 11.2 µg/kg of butyl acetate with a fruity note could significantly mask WOF. In conclusion, WOF in surimi gels could be masked by YE due to the high concentrations of pyrazines and esters. Practical Application: Yeast extracts could decrease the warmed-over flavor (WOF) due to the high concentrations of pyrazines (baked-potato note) and esters (fruity note). This finding extends the application of yeast extracts in the food industry. On the other hand, this study presents a reasonable solution for the reduction of WOF in surimi products.

Advances in flavor peptides with sodium-reducing ability: A review

Condiments (such as sodium chloride and glutamate sodium) cause consumers to ingest too much sodium and may lead to a variety of diseases, thus decreasing their quality of life. Recently, a salt reduction strategy using flavor peptides has been established. However, the development of this strategy has not been well adopted by the food industry. There is an acute need to screen for peptides with salty and umami taste, and to understand their taste characteristic and taste mechanism. This review provides a thorough analysis of the literature on flavor peptides with sodium-reducing ability, involving their preparation, taste characteristic, taste mechanism and applications in the food industry. Flavor peptides come from a wide range of sources and can be sourced abundantly from natural foods. Flavor peptides with salty and umami tastes are mainly composed of umami amino acids. Differences in amino acid sequences, spatial structures and food matrices will cause different tastes in flavor peptides, mostly attributed to the interaction between peptides and taste receptors. In addition to being used in condiments, flavor peptides have also anti-hypertensive, anti-inflammatory and anti-oxidant abilities, offering the potential to be used as functional ingredients, thus making their future in the food industry extremely promising.

Comparison of Different Deodorizing Treatments on the Flavor of Paddy Field Carp, Analyzed by the E-Nose, E-Tongue and Gas Chromatography-Ion Mobility Spectrometry

Changes in the flavor and taste profiles of Paddy Field Carp after deodorization with perilla juice (PJ), cooking wine (CW) and a mixture of the two (PJ-CW) were analyzed using the E-nose, E-tongue, gas chromatography-ion mobility spectrometry (GC-IMS), free amino acid analysis and taste nucleotide analysis. The E-nose and E-tongue revealed that deodorization reduced the content of sulfur-containing compounds, enhanced umami, bitterness, sourness and astringency, and decreased saltiness. PCA and OPLS-DA analysis successfully distinguished between the effects of the treatments. Free amino acids increased from 8777.67 to 11,125.98 mg/100 g and umami amino acids increased from 128.24 to 150.37 mg/100 g after PJ-CW deodorization (p < 0.05). Equivalent umami concentration (EUC) comparisons showed that PJ-CW treatment produced the greatest synergistic umami enhancement (to 3.15 g MSG equiv./100 g). GC-IMS detected 52 aroma compounds; PJ treatment produced the greatest diversity of aldehydes, including heptanal, nonanal, hexanal, 3-methylbutanal, (E)-2-heptenal and (E,E)-2,4-heptadienal. The total content of volatile flavor compounds was the highest after PJ-CW treatment, and the content of many characteristic flavor substances (3-hydroxy-2-butanone, benzaldehyde, 5-methyl-2(3H)-furanone) increased. These findings provided a theoretical basis for the further development of deodorization methods for Paddy Field Carp.

Using temporal dominance of sensations (TDS), multiple-sip TDS, chemical composition evaluation, and microstructural analysis to assess the impact of repeated reheating cycles on chicken soup

Reheating chicken soup is a common culinary practice in daily life. To investigate the impact of reheating frequency on the sensory quality of chicken soup, temporal dominance of sensations (TDS) and multi-TDS were used to characterize changes in dominant sensory attributes during consumption. Additionally, E-nose and E-tongue were utilized to analyze differences in aroma and taste profiles. The alterations in sensory properties were further elucidated by analyzing variations in amino acids, volatile compounds. The findings revealed that there was no significant disparity between fresh soup and heating. However, saltiness and umami, as the most prominent dominant characteristics, intensified with increasing reheating cycles. This can be attributed to an elevation in certain amino acids that contribute to umami perception. Conversely, a reduction in some aldehydes weakened the flavor associated with fat and meat components. Moreover, enlarged oil droplets with uneven distribution within heated soup may account for the heightened greasiness sensation.

Insights into the potential mechanism of liquid nitrogen spray freezing's influence on volatile compounds in surimi gels with different cross-linking degrees: Focus on oxidation, protein structure, intermolecular force and free amino acid alterations

This study revealed the variations in odor characteristics and underlying mechanisms of different cross-linked surimi gels under liquid nitrogen (LN) spray freezing. The results demonstrated that LN spray freezing had an essential effect on the gels' odor. The odor changes in the -80 °C LN spray freezing group were closer to the control group, while -35 °C LN spray freezing treatment had the greatest impact on the aroma quality of gels. Freezing reduced gels' texture properties, intensified lipid and protein oxidation, altered protein conformation, increased surface hydrophobicity and hydrophobic interactions. These changes affected the gels' odor characteristics, leading to a reduction in fish aroma and an increase in fishy and oil odors after freezing. These tendencies were more pronounced at -35 °C LN spray freezing with lower cross-linking degrees, and reducing the freezing temperature to -80 °C and increasing the cross-linking degree to 62.99% mitigated the extent of deterioration in gel flavor quality.

Unraveling the binding mechanisms of transglutaminase and substrate subjected to microwaves: Molecular docking and molecular dynamic simulations

Previous studies showed that transglutaminase (TGase) and microwaves acted synergistically to improve the functional properties of proteins. The mechanism behind this has yet to be elucidated. In this study, the phenomenon of microwaves enhancing TGase activity was experimentally validated. Molecular docking and molecular dynamics simulations revealed that moderate microwaves (105 and 108 V/m) increased the structural flexibility of TGase and promoted the orientation of the side chain carboxylate anion group on Asp255, driving the reaction forward. Also, TGase underwent partial transformation from α-helix to turns or coils at 105 and 108 V/m, exposing more residues in the active site and facilitating the binding of the substrate (CBZ-Gln-Gly) to TGase. However, 109 V/m microwaves completely destroyed the TGase structure, inactivating the enzyme. This study provides insights into the molecular mechanisms underlying the interactions between TGase and substrate subjected to microwaves, promoting the future applications of TGase and microwaves in food processing.

Modulating peppermint oil flavor release properties of emulsion-filled protein gels: Impact of cross-linking method and matrix composition

For some food applications, it is desirable to control the flavor release profiles of volatile flavor compounds. In this study, the effects of crosslinking method and protein composition on the flavor release properties of emulsion-filled protein hydrogels were explored, using peppermint essential oil as a model volatile compound. Emulsion-filled protein gels with different properties were prepared using different crosslinking methods and gelatin concentrations. Flavor release from the emulsion gels was then monitored using an electronic nose, gas chromatography-mass spectrometry (GC-MS), and sensory evaluation. Enzyme-crosslinked gels had greater hardness and storage modulus than heat-crosslinked ones. The hardness and storage modulus of the gels increased with increasing gelatin concentration. For similar gel compositions, flavor release and sensory perception were faster from the heat-crosslinked gels than the enzyme-crosslinked ones. For the same crosslinking method, flavor release and perception decreased with increasing gelatin concentration, which was attributed to retardation of flavor diffusion through the hydrogel matrix. Overall, this study shows that the release of hydrophobic aromatic substances can be modulated by controlling the composition and crosslinking of protein hydrogels, which may be useful for certain food applications.

Changes in the Quality and Microbial Communities of Precooked Seasoned Crayfish Tail Treated with Microwave and Biological Preservatives during Room Temperature Storage

The qualities of precooked foods can be significantly changed by the microorganisms produced during room temperature storage. This work assessed the effects of different antibacterial treatments (CK, without any treatment; microwave treatment, MS; microwave treatment and biological preservatives, MSBP) on the physicochemical properties and microbial communities of precooked crayfish tails during room temperature storage. Only the combination of microwave sterilization and biological preservatives significantly inhibited spoilage, as evidenced by the total viable count (4.15 log CFU/g) after 3 days of room temperature storage, which satisfied the transit time of most logistics companies in China. Changes in pH and TVB-N were also significantly inhibited in the MSBP group compared with those in the CK and MS groups. More than 30 new volatile compounds were produced in the CK groups during room temperature storage. However, in the MSBP groups, the volatile compounds were almost unchanged. The correlations between the microbial composition and volatile compounds suggested that specific bacterial species with metabolic activities related to amino acid, energy, cofactor, and vitamin metabolism, as well as xenobiotics biodegradation and metabolism, were responsible for the changes in volatile compounds. These bacteria included Psychrobacter, Arthrobacter, Facklamia, Leucobacter, Corynebacterium, Erysipelothrix, Devosia, Dietzia, and Acidovorax. Overall, our findings provide a foundation for the development of strategies to inhibit spoilage in precooked crayfish tails stored at room temperature.

Design of colloid structure to realize gel salt reduction: a review

Excessive consumption of salt is associated with increased incidence of cardiovascular diseases, hypertension, diabetes, and other health issues. However, it is challenging to find appropriate strategies that balance sensory qualities while achieving sodium reduction as salt plays a crucial role in providing desired appearance, texture, and taste. The impact of hydrocolloid properties (addition and type) on saltiness perception were reviewed. Additionally, considering the interactions between food components, both covalent and noncovalent, we propose designing specialized colloidal structures capable of binding sodium ions to enhance salt-taste perception. The effects of hydrocolloids on the physicochemical, structural, and sensory qualities of gel foods are then discussed. Finally, by addressing current issues with low-salt foods and consumer demands, we provide a future outlook for low-salt food development. The selection of suitable hydrocolloids and precise control of the addition are crucial considerations for achieving salt reduction. The interaction between hydrocolloids and other food components can be utilized to design specialized colloidal structures, thereby accomplishing gel-based salt reduction and enhancing properties. This review serves as a theoretical reference for developing healthy, nutritious, and flavorful low-salt foods that can aid in the prevention and mitigation of diseases associated with excessive salt consumption.

Comparison of volatile aroma compounds in commercial surimi and their products from freshwater fish and marine fish and aroma fingerprints establishment based on metabolomics analysis methods

Understanding the differences in odors of freshwater and marine fish surimi and their products is important for the quality control of surimi products. Aroma compounds in silver carp surimi and three kinds of marine fish surimi and their products were identified by gas chromatography-mass spectrometry/olfactometry, and aroma fingerprints of them were established based on metabolomics analysis methods. Silver carp surimi and surimi products showed the highest "fresh fish" and "grassy, earthy" notes, while the marine fish surimi and their products presented a strong "sea breeze-like" odor. Five Br-containing compounds (sea breeze-like) were identified in the marine fish samples. The aroma fingerprints showed that the odor compositions of freshwater and marine surimi/surimi products were divided into two categories, and the marine fish surimi and their products also showed differences in odors. Furthermore, four commercial surimi and their products could be distinguished according to 33 and 28 differential aroma components, respectively.

Effects of freezing methods on physicochemical properties, protein/fat oxidation and odor characteristics of surimi gels with different cross-linking degrees

This work investigated the effects of liquid nitrogen immersion freezing (LNF), -35 °C air freezing (AF-35℃) and -18 °C air freezing (AF-18℃) on the physical and chemical characteristics and flavor quality of surimi gels with different cross-linking degrees. Compared to AF-35 °C and AF-18 °C, LNF was shown to considerably delay the texture deterioration and water migration of frozen gels, as well as the accumulation of thiobarbituric acid reactive substance values and carbonyl contents. Additionally, an appropriate increase of cross-linking degree (45.83 to 62.99%) was found able to improve gel properties and inhibit quality deterioration during freezing. Moreover, LNF-treated gels were closer to fresh gels in the amount of volatile compounds, in contrast to most significant negative aroma changes in AF-18℃-treated gels. Furthermore, 29, 29 and 31 key differential volatile compounds were screened for gels with a cross-linking degree of 29.66, 45.83 and 62.99%, respectively, mainly including aldehydes, alcohols and esters.

Effect of raw material frozen storage on physicochemical properties and flavor compounds of fermented mandarin fish (Siniperca chuatsi)

Frozen mandarin fish (MF) is utilized for preparation fermented MF. However, how raw material (RM) affects the quality and flavor of fermented MF is unclear. This study investigated the impact and mechanism of RM frozen storage on the microstructure, texture, water distribution, and flavor of fermented MF by light microscopy, texture profile analysis, low-field nuclear magnetic resonance, gas chromatography-ion mobility spectrometry, and multivariate analysis. With increasing RM frozen storage time, both frozen MF and frozen-based fermented MF decreased in muscle fiber density while increased in muscle fiber diameter. Additionally, RM frozen storage exhibited a significant impact on the water distribution of frozen MF, while no obvious effect on that of frozen-based fermented MF. Seven odorant (2-methyl-1-propanol, 3-hydroxy-2-butanone, 2,3-butanedione, hexanal-D, ethyl acetate-D, 3-pentanone, and acetone) were shown as potential markers to distinguish fermented MF. This study could provide a theoretical basis for the production of high-quality frozen-based fermented MF.

Flavor and sensory profile of Chinese traditional fish noodles produced by different silver carp (hypophthalmichthys molitrix) mince ingredients

This study employs sensory evaluation, headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) techniques to investigate the effect of different pretreatment of fresh silver carp mince (running water rinsing 0, 1, or 2 times) and commercially frozen surimi on the odor characteristics of fish noodles. The free choice profiling (FCP) and check all that apply (CATA) sensory analysis methods were utilized to identify 10 characteristic descriptors, which include "grass, fish fragrance, unpleasant fishy, fatty, roast, ammonia, caramel, warmed-over, earthy, and mushroomy". HS-GC-IMS and HS-SPME-GC-MS detected 80 and 37 volatile compounds (VCs) in fish noodles. The 1-Penten-3-ol, (E)-2-pentenal-D, hexanal-D, pentanal-D, (E,E)-2, 4-heptadienal-D contents were significantly correlated with "fish fragrance" and "unpleasant fishy", and octanal, nonanal, heptanal, 2-methylpyrazine contents were significantly correlated with "warmed-over" flavor. The results of this study can be helpful for fish noodle quality improvement and industrial production.

Effects of Sous-Vide on Quality, Structure and Flavor Characteristics of Tilapia Fillets

To investigate the effects of traditional high-temperature cooking and sous-vide cooking on the quality of tilapia fillets, muscle microstructure, texture, lipid oxidation, protein structure, and volatile compounds were analyzed. In comparison with samples subjected to traditional high-temperature cooking, sous-vide-treated samples exhibited less protein denaturation, a secondary structure dominated by α-helices, a stable and compact structure, a significantly higher moisture content, and fewer gaps in muscle fibers. The hardness of the sous-vide-treated samples was higher than that of control samples, and the extent of lipid oxidation was significantly reduced. The sous-vide cooking technique resulted in notable changes in the composition and relative content of volatile compounds, notably leading to an increase in the presence of 1-octen-3-ol, α-pinene, and dimethyl sulfide, and a decrease in the levels of hexanal, D-limonene, and methanethiol. Sous-vide treatment significantly enhanced the structural stability, hardness, and springiness of muscle fibers in tilapia fillets and reduced nutrient loss, enriched flavor, and mitigated effects on taste and fishy odor.

Selection and quantification of volatile indicators for quality deterioration of reheated pork based on simultaneously extracting volatiles and reheating precooked pork

This study was to screen and quantify characteristic volatiles tied to the quality deterioration of reheated pork via simultaneously reheating (75 °C, 30 min) and collecting headspace volatiles of precooked pork (100 °C, 10 min; stored: 0 °C, 0-14 d) for GC-MS analysis. The concentrations of hexanal (6.05 ± 0.86-12.05 ± 0.44 mg/kg), (E)-2-octenal (1.54 ± 0.16-3.07 ± 0.08 mg/kg), (E,E)-2,4-heptadienal (1.52 ± 0.44-2.58 ± 0.31 mg/kg) and 8 other selected volatiles in reheated pork increased as the storage time of the precooked counterparts increased. The increase rate of hexanal was 2.9-199 times faster than that of other volatiles based on zero-order reaction fitting (R² = 0.876-0.997). Results from clustering analysis of these volatiles were consistent with their formation pathways tied to lipid autooxidation. This simple approach, reheating and collecting volatiles of precooked meat concurrently, introduces a new possibility for standardizing volatile analysis of precooked meats required being reheated before consumption.

Effects of Cooking Processes on Protein Nutritional Values and Volatile Flavor Substances of Silver Carp (Hypophthalmichthys molitrix)

Silver carp (Hypophthalmichthys molitrix) is normally cooked at a high temperature. In order to explore the effects of cooking methods on the protein nutritional values and volatile flavor substances of silver carp meat, the meat was fried, roasted and steamed, and its contents were determined in relation to moisture, protein, fat, ash, amino acids and volatile flavor substances. The results show that the moisture content of cooked silver carp can be ranked as follows: raw > steamed > roasted > fried. The protein content order of the four samples can be ranked: fried > roasted > raw > steamed. The ash and the fat contents of the four samples showed similar significant (p < 0.05) differences, in the order of fried > roasted > steamed > raw. The contents of all the amino acids in the fried meat were significantly (p < 0.05) higher than the contents in others, and the frying, roasting and steaming processes improved the umami taste (supported by the increased content of glutamate and aspartate) and the protein nutritional value (supported by the amino acid score, essential amino acid index and protein efficiency ratio) of the silver carp meat. A total of 51 compounds were detected in the fried, roasted and steamed meat. Frying and roasting reduced the fishy flavor of this meat. The odor activity value (OAV) indicated that methanethiol, 1-octen-3-ol and 2-heptanone were the key flavor chemicals in raw meat. Hexanal, propionaldehyde, octanal, nonanal, decanal, 1-octen-3-ol and 2-heptanone were key to the flavor of fried meat. Pentanal, decanal, methyl mercap-tan and 1-octen-3-ol contributed greatly to the overall flavor of the roasted meat. Nonanal, methylmercaptan and 1-octene-3-ol had strong effects on the flavor of the steamed silver carp meat.

The Sous Vide Cooking of Mediterranean Mussel (Mytilus galloprovincialis): Safety and Quality Assessment

This study involves an investigation of the effects of various cooking temperatures, freeze-thaw processes, and food preservatives on the quality and shelf-life of sous vide Mediterranean mussels. Cooking temperatures of 80 °C or above significantly improved the microbiological quality, with bacterial counts remaining within the acceptability range for human consumption even after 21 days of refrigerated storage. Fast freezing followed by slow thawing preserved the highest moisture content, potentially improving texture. Sensory analysis revealed that refrigerated sous vide mussels maintained a comparable taste to freshly cooked samples. Frozen samples reheated via microwaving exhibited more intense flavour than pan-reheated or fresh mussels. Food additives, including citric acid, potassium benzoate, and potassium sorbate, alone or in combination with grape seed oil, significantly reduced total volatile basic nitrogen and thiobarbituric acid-reactive substances during 28 days of storage, indicating decreased spoilage and lipid oxidation. Mussels with a combination of these additives registered a nitrogen content as low as 22 mg of N/100g after 28 days, well below the limit of acceptability (<35 mg of N/100g). Food additives also inhibited bacterial growth, with mesophilic bacteria count below 3.35 Log CFU/g after 28 days, compared with 5.37 Log CFU/g in control samples. This study provides valuable insights for developing optimal cooking and preservation methods for sous vide cooked seafood, underscoring the need for further research on optimal cooking and freeze-thaw protocols for various seafood types.

The odor deterioration of tilapia (Oreochromis mossambicus) fillets during cold storage revealed by LC-MS based metabolomics and HS-SPME-GC-MS analysis

Odor deterioration of tilapia during cold storage is unavoidable and affects flavor and quality severely. Odor is characterized by the abundance of volatile compounds and metabolites. In this study, headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and metabolomic analysis were applied to explore the volatile compounds, differential metabolites, and metabolic pathways related to the odor deterioration of tilapia during cold storage. A total of 29 volatile compounds were detected to be associated with the odor deterioration of tilapia. And 485 differential metabolites were screened, of which 386 differential expressions were up-regulated and 99 differential expressions were down-regulated. Three major metabolic pathways including linoleic acid metabolism, alanine, aspartate, glutamate metabolism, and nucleotide metabolism were obtained. A potential metabolic network map was also proposed. This study contributes to revealing the metabolic mechanisms of odor deterioration in tilapia during cold storage and providing a theoretical reference for the regulation of flavor and quality.