Differentiation of Penaeus vannamei from different thermal processing methods in physico-chemical, flavor and sensory characteristics

The revelation of characteristic volatile compounds in egg powder and analysis of their adsorption rules based on HS-GC-IMS technology

The study constructed fingerprints and analyzed adsorption rules of volatile compounds (VOCs) in egg powder (EP) under different production processes, including egg white powder (EWP), egg yolk powder (EYP) and whole egg powder (WEP) by HS-GC-IMS. The 29 VOCs identified were primarily ketones and aldehydes. Characteristic VOCs responsible for flavor differences were clarified by difference comparison, clustering and PCA analysis. Additionally, variations in lipid and protein were the primary causes of the VOCs differences in EP through microscopy imaging, infrared and fluorescence spectroscopy. EWP's stretched structure favored fishy-smelling VOCs adsorption but limited total aldehyde binding due to strong hydrophobic interaction. EYP's higher β-sheet ratio and fewer hydrogen bond sites weakened its alcohol VOCs binding capacity. The abundance of ketone VOCs in EP was linked to their low steric hindrance. Therefore, this study elucidated the flavor differences reasons among EWP, EYP and WEP, laying foundation for EP applications in food industry.

Identification of key physicochemical properties and volatile flavor compounds for the sensory formation of roasted tilapia

Tilapia is suitable for industrial roasting production because of its good flavor and processing adaptability. In this study, the key physicochemical properties and volatile compounds for sensory formation of roasted tilapia were identified after roasting condition optimization. The highest sensory score was obtained at 215 °C, 45 min, and 4% oil. During roasting, the a*, b*, hardness, chewiness, and oxidation of proteins and lipids significantly increased, the moisture content decreased, and the myofibrillar protein aggregation was observed by scanning electron microscope. After identification and quantification by headspace-gas chromatography-ion mobility spectrometry, 10 compounds with odor active value ≥1 were selected as characteristic flavor compounds. The correlation network indicated that the sensory formation mainly resulted from Maillard reaction, myofibrillar protein aggregation, and improvement of pleasant volatile flavor compounds induced by oxidation of proteins and lipids and water loss. This study provides an important theoretical basis and technical support for roasted tilapia production.

Influence of beeswax-based fish oil oleogels on the mechanism of water and oil retention in Pacific white shrimp (Litopenaeus vannamei) meat emulsion gels: Filling, emulsification and phase transition

Oleogels have been used in the gelled surimi products to replace animal fats due to its structure characteristics. The effect of structure characteristics in fish oil oleogels on the mechanism of oil/water retention was investigated in meat emulsions. Beeswax assembly improved the oil and water retention. The unsaturation degree of fatty acids lowered the mobility of bound water, immobilized water as well as bound fat in the fish oil oleogel, but enhanced the mobility of free water and protons of unsaturated fatty acids. Beeswax addition and oil phase characteristics could enhance β-sheets, disulfide bonds and hydrophobic force to improve the viscoelasticity, gel strength and oil/water retention. Beeswax assembly facilitated the tight micro-sol network and filling effect, and high unsaturation degree promoted the emulsification effect, thus reducing phase transition temperature and juice loss. The study could lay the foundation for development of gelled shrimp meat products with EPA and DHA.

Optimizing color enhancement in dried Penaeus vannamei through high-humidity hot air impingement cooking: Enzyme inactivation, reduced drying time, and Maillard reaction inhibition

This study was aimed to evaluate the potential of high-humidity hot air impingement cooking (HHAIC) on Penaeus vannamei, focusing on its drying characteristics, microstructure, water distribution, enzyme activity, astaxanthin content, antioxidant capacity, color, and Maillard reaction. Results demonstrated that a 3 min HHAIC significantly improved the shrimp's color and optimized astaxanthin content with a notable increase in scavenging capacity based on an in-vitro as antioxidation activity evaluation. Compared to the untreated samples, HHAIC could significantly inactivate polyphenol oxidase by 95.76%. Also, it suppressed the Maillard reaction by decreasing 5-hydroxymethylfurfural content and shortened the drying time by 40%. In addition, the low-field nuclear magnetic resonance and microstructure analysis showed alterations in the shrimp muscle fiber structure and water distribution. This study indicated that HHAIC could elevate quality, enhance appearance, and reduce the processing time of dried shrimp, presenting valuable implications for industry progress.

Elucidating the effects of precooked treatments on the quality attributes of red swamp crayfish (Procambarus clarkia): Insights from water boiling vs. microwaving

Precooked treatments are essential in food processing, extending beyond mere sterilization to include the enhancement of nutritional value, flavor profile, and digestibility. This research scrutinizes the effects of water boiling and microwaving on red swamp crayfish, two distinct precooked methodologies. A comparative analytical framework has been employed to assess the efficacy of two precooked methods across a spectrum of quality indicators, including aerobic plate counts, texture, nutrient composition, volatile compound characterization, protein oxidation, and digestive properties. The findings revealed that both water boiling and microwaving effectively reduced bacterial counts to a safe level of 500 CFU/g. Microwave precooking facilitated a moderate oxidation of lipids in crayfish, preferentially liberating flavor compounds, thereby enhancing their sensory attributes. The boiling process imparted a pronounced denaturation to proteins, consequently augmenting the hardness of the crayfish. Notably, the enhanced digestibility of boiled crayfish proteins results from the denaturing action of boiling, promoting efficient protein digestion.

Evaluating shelf life and anti-browning of shrimp by chitosan-coated nanoliposome loaded with licorice root extract

Chitosan coating containing nanoliposomes loaded with licorice root extract was prepared to investigate shrimp's shelf life and anti-browning function during 20 days of ice storage. 1% licorice root hydroethanolic extract (LHE) was encapsulated in nanoliposomes or coated with chitosan, and then the shrimp were immersed in coating solutions. LHE treatment had the lowest browning indices (5 and 1.02), TBA (0.32 mg MDA/kg), and FFA (0.01%). Chitosan-coated LHE treatment (Ch-LHE) showed the best performance for TVN, microbial counts, and discoloration. PV, WHC, and cook loss in the treatment with LHE nanoliposome coated with chitosan (Ch-N-LHE) were measured at acceptable levels of 0.53 meq/kg, 86.12%, and 15.06%, respectively. Experiments showed that pure or encapsulated LHE is an effective method for increasing the quality and preventing the browning of shrimp. Additionally, due to its cost-effectiveness and health benefits, it can be an effective natural substitute for sodium metabisulfite at the global export level.

Investigating the quality discrepancy between different salmon and tracing the key lipid precursors of roasted flavor

Differences in raw material characteristics directly affect the processing characteristics and quality of the final product. Therefore, it is important for the salmon industry to start regulating or grading from raw material side. In this study, the material characteristics and flavor quality of three different salmons: Atlantic salmon, red salmon, and pink salmon were evaluated. Trans-2,cis-6-nonadienal, octanal, and cis-4-heptenal contributed to the fishy aroma of roasted salmon, while fresh salmon was mainly caused by octanal. The oily aroma of fresh salmon was relevant to octanal, decanal, and 1-heptanol. The results indicated that the composition of phospholipids affect the flavor of roasted salmon, such as phosphatidylethanolamines and phosphatidylcholines, were closely related to the roasted and fishy aroma of roasted salmon. This study revealed that roasting could reduce the sensory quality difference between salmon by changing the textural property and volatile compound profile, provide guidance for production, grading, and consumption of salmon.

Effects of phenolic acid grafted-chitosan hydrocolloids on the aldehyde contents from lipid oxidation in golden pompano (Trachinotus blochii) fillets during pan-frying

The effects of phenolic acid grafted-chitosan hydrocolloids (CS-g-GA/FA) on aldehyde contents from lipid oxidation in golden pompano fillets during pan-frying was investigated with an established high-performance liquid chromatography-mass spectrum method. Results indicated that pan-frying induced profound lipid oxidation and aldehydes generation with propanal, hexanal, nonanal, trans, trans-2,4-decadienal, and 4-hydroxy-2-nonenal as the abundant species. CS-g-FA and CS-g-GA effectively decreased their contents by 23.74-27.42 %, 61.69-67.42 %, 41.83-53.91 %, 29.91-48.79 %, and 61.57-65.39 % after 3 min. Most aldehyde contents decreased with the extension of pan-frying time due to the volatilization and reaction. In terms of substrate depletion, CS-g-phenolic acids effectively inhibited unsaturated fatty acids oxidation due to their decent antioxidant activity than CS. The significant lower retention rates of aldehydes in the CS-g-phenolic acids groups compared with control in chemical mode confirmed the carbonyl ammonia condensation. These results suggested that CS-g-phenolic acids serve as novel coating to reduce hazardous compounds during aquatic products thermal processing.

Effects of different thermal sterilization conditions on the quality of ready-to-eat shrimp based on specific sterilization intensity

The effects of different thermal sterilization conditions on the quality and digestibility of ready-to-eat (RTE) shrimp were investigated. Compared with the high-temperature (121 °C) and short-time (6 min and 8 min) sterilization, the low-temperature (110 and 115 °C) and long-time (>20 min) sterilization significantly promoted the Maillard and browning reactions and changed the color of the RTE-shrimp. The high sterilization temperature promoted shrimp protein oxidation, resulting in increased carbonyl group, disulfide bond, and free radical content, while the free sulfhydryl group content decreased. This oxidation and tissue destruction at high temperature led to reduced texture properties and altered water distribution within the shrimp's muscles. However, sterilized shrimp exhibited superior digestive properties in an in vitro simulated digestion experiment. High-temperature and short-time sterilization is more effective in mitigating the quality deterioration of RTE-shrimp compared to low-temperature and long-time sterilization.

Nutritional and physicochemical characteristics of Asiatic hard clam powder prepared by different cook-drying processes: a comparative study

BACKGROUND

Asiatic hard clam (Meretrix meretrix) is an underutilized bivalve resource. This study discusses dried clam powders prepared from this resource to enhance its utilization and improve nutritional security in protein-deficient populations. Dried clam powder was prepared from Asiatic hard clam and the effects of different pre-cooking methods (boil-dried clam powder, BDCP; steam-dried clam powder, SDCP; and microwave-dried clam powder, MDCP) on nutritional (proximate composition, amino acid profiling, mineral profiling, fatty acid profiling) and physicochemical qualities were investigated.

RESULTS

Different pre-cooking methods significantly influenced the characteristics of the clam powder. The MDCP sample showed the highest concentration of amino acids, polyunsaturated fatty acids, Na, K, Ca and Mg content compared to BDCP and SDCP. The boiling process led to a loss of nutritional quality in terms of amino acids and macrominerals. The MDCP displayed the highest solubility in water (30.10%) but its oil and water absorption characteristics were the lowest among all the samples. Boil-cooked clam powder displayed the highest oil binding (2.03 mL g-1 protein) capacity. Boiling and steaming processes resulted in malondialdehyde generation compared to microwaving. Different pre-cooking processes did not influence the colour attributes significantly, but the control sample prepared without pre-cooking (CCP) had a significantly lower L* value (32.34), resulting in a darker product. In vitro digestibility of the clam powder varied in the order MDCP > SDCP > BDCP > CCP.

CONCLUSION

The study demonstrated that nutritionally rich protein powder can be prepared from Asiatic hard clam. Based on the results, microwave pre-cooking is considered the best pre-cooking method to preserve the nutritional qualities of clam powder. © 2024 Society of Chemical Industry.

The formation and conversion of characteristic aroma profiles and key harmful substances in different high-temperature processing of hairtail (Trichiurus Haumela)

The balance regulation between characteristic aroma and hazards in high-temperature processed fish is a hot spot. This study was aimed to explore the interactive relationship between the nutritional value, microstructures, aroma, and harmful substances of hairtail under different frying methods including traditional frying (TF), air frying (AF), and vacuum frying (VF) via chemical pattern recognition. The results indicated that VF-prepared hairtail could form a crunchy mouthfeel and retain the highest content of protein (645.53 mg/g) and the lowest content of fat (242.03 mg/g). Vacuum frying reduced lipid oxidation in hairtail, resulting in the POV reaching 0.02 mg/g, significantly lower than that of TF (0.05 mg/g) and AF (0.21 mg/g), and TBARS reached 0.83 mg/g, significantly lower than that of AF (1.96 mg/g) (P < 0.05), respectively. Notable variations were observedin the aroma profileof hairtail preparedfrom different frying methods. Vacuum frying of hairtail resulted in higher levels of pyrazines and alcohols, whereas traditional frying and air frying were associated with the formation of aldehydes and ketones, respectively. Air frying was not a healthy way to cook hairtail which produced the highest concentration of harmful substances (up to 190.63 ng/g), significantly higher than VF (5.72 ng/g) and TF (52.78 ng/g) (P < 0.05), especially norharman (122.57 ng/g), significantly higher than VF (4.50 ng/g) and TF (32.63 ng/g) (P < 0.05). Norharman and acrylamide were the key harmful substances in hairtail treated with traditional frying. The vacuum frying method was an excellent alternative for deep-fried hairtail as a snack food with fewer harmful substances and a fine aroma, providing a theoretic guidance for preparing healthy hairtail food with high nutrition and superior sensory attraction.

Effect of κ-carrageenan on the quality of crayfish surimi gels

The demand for crayfish surimi products has grown recently due to its high protein content. This study examined the effects of varying κ-carrageenan (CAR) and crayfish surimi (CSM) concentrations on the gelling properties of CAR-CSM composite gel and its intrinsic formation process. Our findings demonstrated that with the increasing concentration of carrageenan, the quality of CAR-CSM exhibited rising trend followed by subsequently fall. Based on the textural qualities, the highest quality CAR-CSM was achieved at 0.3% carrageenan addition. With the exception of chewiness, and the cooking loss of the gel system was 1.62%, whiteness was 82.35%, and the percentage of β-sheets increased to 57.18%. Further increase in CAR (0.4-0.5%) addition resulted in internal build-up of LCAR-CSM, conversion of intermolecular forces into disulfide bonds and gel breakage. This study exudes timely recommendations for extending the CAR application for the continuous development of crayfish surimi and its derivatives and its overall economic worth.

Molecular modelling studies reveal cryoprotective mechanism of L-Proline during the frozen storage of shrimp (Litopenaeus vannamei)

This study aimed to investigate the cryoprotective properties of proline (1% and 3% (w/v)) on shrimp. The cryoprotective mechanism was studied using physico-chemical experiments and molecular simulations. Proline had a notable positive impact on the thawing loss and texture of shrimp in comparison to the control. The denaturation of myosin in frozen shrimp was delayed by proline. Microscopy analysis demonstrated that proline effectively lowered the harm caused by ice crystals to shrimp muscle. Molecular simulations indicated that proline potentially exerted a cryoprotective effect primarily through the "water substitution" and "glassy state" hypotheses. Proline formed hydrogen bonds with myosin to replace the water molecules around myosin. Additionally, proline interacted with water molecules to form a glassy state, impeding the growth of ice crystals. Consequently, the stability of shrimp myosin was enhanced during freezing. In conclusion, proline demonstrated promise as an efficacious cryoprotectant for aquatic products.

Effect of ultrasound combined with pineapple protease treatment on the tenderness of dried shrimp

BACKGROUND

In order to improve the tenderness of dried shrimp products as well as to reduce the hardness of the meat during the drying process, shrimp were treated with ultrasound combined with pineapple protease and the tenderization condition was optimized by measuring the texture and shear force of dried shrimp. In addition, the sulfhydryl content, myofibril fragmentation index (MFI) and microstructure were also examined to clarify the mechanisms of shrimp tenderization.

RESULTS

The results showed UB1 group with ultrasonic power of 100 W, heating temperature of 50 °C and pineapple protease concentration of 20 U mL-1 were the optimum tenderization conditions, where shrimp showed the lowest hardness (490.76 g) and shear force (2006.35 gf). Microstructure as well as sodium dodecyl sulfate-polyacrylamide gel electrophoresis results suggested that during the tenderization process the muscle segments of shrimps were broken, degradation of myofibrillar proteins occurred, and MFI values and total sulfhydryl content increased significantly (P < 0.05) (MFI value = 193.6 and total sulfhydryl content = 93.93 mmol mg-1 protein for UB 1 group).

CONCLUSION

Ultrasound combined with bromelain could be used as a simple and effective tenderization method for the production of tender dried shrimp. The best conditions were 100 W ultrasonic power, 50 °C ultrasonic temperature, and 20 U mL-1 bromelain. © 2024 Society of Chemical Industry.

Differentiation of antioxidants in reducing oxidation and improving quality of ready-to-eat roasted shrimp after thermal sterilization

Sterilization is essential for ready-to-eat foods; however, it tends to degrade the quality of the product. To explore the role of antioxidants in regulating the edible quality of roasted Pacific white shrimp after sterilization, color changes, degree of oxidation, microstructure and quality of roasted shrimp treated with tea polyphenols, phytic acid, rosemary extract, and d-sodium erythorbate were investigated. Tea polyphenol-treated roasted shrimp had the lowest Maillard intermediate products and browning strength after sterilization; phytic acid significantly reduced carbonyl content and TBARS value; rosemary extract exhibited the lowest level of free radicals, while d-sodium erythorbate preserved a relatively intact myofibrillar structure. Correlation analysis revealed a negative correlation between the degree of oxidation and the edible quality of roasted shrimp after sterilization. Therefore, the addition of antioxidants inhibited oxidation and improved the quality of roasted shrimp, and different antioxidants had diverse effects on the quality improvement of roasted shrimp after thermal sterilization.

Research progress of fishy odor in aquatic products: From substance identification, formation mechanism, to elimination pathway

Fishy odor in aquatic products has a significant impact on the purchasing decisions of consumers. The production of aquatic products is a complex process involving culture, processing, transportation, and storage, which contribute to decreases in flavor and quality. This review systematically summarizes the fishy odor composition, identification methods, generation mechanism, and elimination methods of fishy odor compounds from their origin and formation to their elimination. Fishy odor compounds include aldehydes (hexanal, heptanal, and nonanal), alcohols (1-octen-3-ol), sulfur-containing compounds (dimethyl sulfide), and amines (trimethylamine). The mechanism of action of various factors affecting fishy odor is revealed, including environmental factors, enzymatic reactions, lipid oxidation, protein degradation, and microbial metabolism. Furthermore, the control and removal of fishy odor are briefly summarized and discussed, including masking, elimination, and conversion. This study provides a theoretical basis from source to elimination for achieving targeted regulation of the flavor of aquatic products, promoting industrial innovation and upgrading.

PvMR1, a novel C-type lectin plays a crucial role in the antibacterial immune response of Pacific white shrimp, Penaeus vannamei

C-type lectins (CTLs) are important immune molecules in innate immune, which participate in non-self recognition and clearance of pathogens. Here, a new CTL with two distinct C-type lectin domains (CTLDs) from Pacific white shrimp Penaeus vannamei, designated as PvMR1 was identified. The obtained PvMR1 coding sequence (CDS) was 1044 bp long encoding a protein with 347 amino acids. PvMR1 had two CTLD, a conserved mannose-specific EPN motif and a galactose-specific QPD motif, clustering into the same branch as the crustacean CTLs. PvMR1 was widely distributed in shrimp tissues with the highest transcription level in the hepatopancreas, with significantly induced mRNA expression on the hepatopancreas and intestines after immune challenge with Vibrio anguillarum. In vitro assays with recombinant PvMR1 (rPvMR1) protein revealed that it exhibited a wide range of antimicrobial activity, bacterial binding ability, and bacterial agglutination activity in a Ca2+-independent manner. Moreover, PvMR1 promoted bacterial phagocytosis in hemocytes. Furthermore, rPvMR1 treatment could significantly enhance the bacterial clearance in hemolymph and greatly improved the survival of shrimp under V. anguillarum infection in vivo. These results collectively suggest that PvMR1 plays an important role in antibacterial immune response of P. vannamei.

Tandem Mass Tag Proteomics Provides Insights into the Underlying Mechanism of Flesh Quality Degradation of Litopenaeus vannamei during Refrigerated Waterless Transport at 12 °C

Refrigerated waterless transport at 12 °C of live shrimp (Litopenaeus vannamei) causes flesh quality deterioration, and the underlying mechanism remains unknown. Herein, proteomics and bioinformatics analyses were used to elucidate the molecular mechanism of flesh quality changes. The result showed that 33 and 44 of the differentially abundant proteins (DAPs) were, respectively, identified in the acute cold (AC) group and the combined stress of acute cold and waterless duration (AC+WD) group, which were mostly involved in the metabolism processes and cellular structure of animal tissues, and notably enriched in biological pathways such as lysosome, glycolysis/gluconeogenesis, and focal adhesion. Furthermore, the changes in color and texture properties were closely associated with tubulin, gelsolin, laminin, trypsin-1, dipeptidyl peptidase, triosephosphate isomerase, and aldehyde dehydrogenase. Therefore, these DAPs could be used as potential biomarkers to monitor the deterioration of shrimp flesh quality during refrigerated waterless transportation.

Formation of AGEs in Penaeus vannamei fried with high oleic acid sunflower oil

Here, we investigated the effects of frying process on the formation of advanced glycation end products (AGEs) in shrimps using Penaeus vannamei as the raw material. The results showed that the oil, malondialdehyde, fluorescent AGEs, carboxymethyl lysine (CML), methylglyoxal hydroimidazolone (MG-H1) and the outer layer carboxyethyl lysine (CEL) content was higher in the fried shrimps than that in the raw unfried shrimps. The outer layer CML, CEL and inner CEL, MG-H1 values all reached the maximum after the first batch of frying (22.43 mg/kg, 304.24 mg/kg, 83.76 mg/kg, and 169.42 mg/kg respectively). However, fluorescent AGEs and MG-H1 of the outer layer reached the maximum after the fifth and fourth batches of frying (1230.0 AU/g and 341.63 mg/kg). Malondialdehyde, fluorescent AGEs, CML, MG-H1, and CEL concentration in the fried shrimps firstly increased and then decreased to stabilization with more frying batches, with higher content in the outer layer of fried shrimps.

A comparative study on the taste quality of Mytilus coruscus under different shucking treatments

Shucking is an indispensable step in the preparation of cooked mussel products, as it facilitates the detachment of meat from the shell. In this study, we comprehensively investigated the effects of boiling, steaming, and microwaving on taste constituents in half-cooked mussel meat. Two-dimensional correlation spectroscopy revealed the key differential taste components of the different shucking groups. Structural equation modeling (SEM) indicated the positive effects of saltiness and bitterness on umami taste, while sweetness and sourness had negative effects on umami taste in half-cooked mussel meat. Furthermore, Glu, Asp, Ala, Arg, betaine, malic acid, succinic acid, glycogen, Cl^-, Na⁺, K⁺, and PO3- 4 were quantitatively determined as the main taste compounds. The steaming shelling group had the most enriched taste components, with the highest equivalent umami concentration compared to the other shelling groups. Hence, steaming shucking may be favored due to abundant tastes and nutrients.

Effect of Drying Process on the Formation of the Characteristic Flavor of Oyster (Crassostrea hongkongensis)

Oysters are nutritious and tasty but difficult to store. Drying can extend the storage period of oysters and give them a unique flavor. In this study, the effects of four drying procedures, namely, vacuum freeze drying (VFD), vacuum drying (VD), natural sun-drying (NSD), and hot air drying (HAD), on the flavor characteristics of oysters (Crassostrea hongkongensis) were investigated using blanched oysters as a control (CK). Results showed that HAD produced more free amino acids than the other methods, but VFD retained the most flavor nucleotides. Compared with cold drying (VFD), hot drying (VD, NSD, and HAD) increased the abundance of organic acids, betaine, and aroma substances. Glutamic acid, alanine, AMP, hexanal, octanal, heptanal, (E, E)-2,4-heptadienal, (E)-2-decenal, nonanal, etc., are defined as the characteristic flavor compounds of dried oysters, with umami, sweet, green, fatty, and fruity aromas being the main organoleptic attributes of dried oysters. Glutamic acid, glycine, betaine, IMP, pentanal, ethyl heptanoate, (E, Z)-2,4-nonadienal, 1-octen-3-one, 2-hexenal, 2-octenal, hexanal, decanal were defined as markers to distinguish different drying methods. Overall, HAD showed improved flavor qualities and characteristics and was better suited for the highly commercialized production of dried oysters.

Effect of gamma irradiation treatment on microstructure, water mobility, flavor, sensory and quality properties of smoked chicken breast

Effect of gamma irradiation on quality, flavor and sensory properties of smoked chicken breasts were investigated. Results indicated irradiation doses >3 kGy were effective for sterilization, while also produced a significant effect on overall quality of smoked chicken breast. Irradiation treatment could inhibit protein oxidation and accelerate lipid oxidation of smoked chicken breasts. High irradiation doses could increase the instability of free and bound water, as well as increase muscle fiber gap and juice loss significantly. Irradiation treatment also promoted free fatty acids and taste-presenting nucleotides degradation, effectively increased fresh-tasting amino acids contents and decreased bitter and sweet-tasting amino acids contents. The types and relative contents of volatiles, especially aldehydes, alcohols, aromatic hydrocarbons, and phenolic compounds, also changed after irradiation, while tartaric, pyruvic, and malic acids decreased. Results obtained can provide valuable reference data for improving the quality and flavor of smoked chicken breasts using gamma irradiation technology.

Effect of two-stage heating treatment on physicochemical properties of shrimp (Penaeus vannamei) meat

BACKGROUND

Changes in the physicochemical properties of shrimp meat treated with two-stage heating were investigated. Currently, shrimp products in the processing process are susceptible to uneven dehydration, shrimp meat shrinkage, which results in rough and hard texture, poor chewiness, and seriously affects the edible quality as well as economic benefits. Improving the utilization value of shrimp resources, expanding its market shares, optimizing the tenderness of shrimp is the key to developing new types of fresh and ready-to-eat shrimp products.

RESULTS

The results indicated that preheating at 30 °C could not affect the quality of shrimp meat significantly (P > 0.05). As the preheating temperature increased from 40 °C to 50 °C, the hardness and shear force of shrimp meat decreased due to the exposure of protein hydrophobic groups, protein aggregation and degradation, muscle fraction broken, and weight loss increase. Further increase in preheating temperature would lead to further aggregation and gelation of proteins, causing hardness and shear force increase. Besides, the results of microstructure showed that preheating at 40 °C and 50 °C could cause the shrimp muscles to become loose.

CONCLUSION

This study showed that the preheating temperature ranging from 40 °C to 50 °C could effectively improve the tenderness of shrimp meat. This study might be useful for developing tenderized shrimp products in the future. © 2022 Society of Chemical Industry.

Contribution of κ-/ι-carrageenan on the gelling properties of shrimp myofibrillar protein and their interaction mechanism exploration

BACKGROUND

The contribution and mechanism of κ-/ι-carrageenan (CG) with different hydration characteristics on the gelling properties of shrimp myofibrillar protein (MP) gelation was studied.

RESULTS

The gel strength, water-holding capacity and viscoelastic properties of MP gels were significantly enhanced by 1.0% κ-/ι-CG (P < 0.05), but the microstructure showed that excessive carrageenan caused fragmentation of the gel network and a corresponding decrease in gel properties. Compared to MP-ιCG, MP-κCG showed larger breaking force and shorter breaking distance, thus enhancing the hardness and brittleness of the gel, which might be ascribed to a reinforced network skeleton and a tighter binding of κCG-myosin. However, MP-ιCG stabilized more moisture in the gel network, thereby improving the tenderness of the gel, which might be related to the electrostatic repulsion observed between the sulfate groups of ιCG and the myosin observed by molecular docking. In addition, the β-sheet content and intermolecular interactions might be positively correlated with gel properties.

CONCLUSION

In this study, a composite gel system was constructed based on the interaction of MP and CG. The quality differences of two kinds of CG-MP gels were clarified, which will provide guidance for the application of different kinds of carrageenan and the development of recombinant meat products with specific quality. © 2022 Society of Chemical Industry.

Characterization of non-volatile and volatile flavor profiles of Coregonus peled meat cooked by different methods

This study investigated the effects of different cooking methods on non-volatile flavor (free amino acids, 5'-nucleotides, and organic acids, etc.) of Coregonus peled meat. The volatile flavor characteristics were also analyzed by electric nose and gas chromatography-ion migration spectrometry (GC-IMS). The results indicated that the content of flavor substances in C. peled meat varied significantly. The electronic tongue results indicated that the richness and umami aftertaste of roasting were significantly greater. The content of sweet free amino acids, 5'-nucleotides, and organic acids was also higher in roasting group. Electronic nose principal component analysis can distinguish C. peled meat cooked (the first two components accounted for 98.50% and 0.97%, respectively). A total of 36 volatile flavor compounds were identified among different groups, including 16 aldehydes, 7 olefine aldehydes, 6 alcohols, 4 ketones, and 3 furans. In general, roasting was recommended and gave more flavor substances in C. peled meat.

Evaluation of Aroma Characteristics of Dried Shrimp (Litopenaeus vannamei) Prepared by Five Different Procedures

Litopenaeus vannamei is one of the most popular shrimp species in the world and has been reported in studies on its dryness and flavor. However, the aroma characteristics of shrimps dried with different drying methods are compared in a unified way, and there are few reports on the difference in aroma of different shrimps dried. In order to clarify the difference in aroma characteristics of shrimp dried produced by different drying methods. In this study, blanched shrimp (BS) was used as a control to analyze the aroma characteristics of shrimp dried by five different procedures (SD-BFDP) samples, namely vacuum freeze-dried shrimp (VFDS), vacuum dried-shrimp (VDS), heat pump-dried shrimp (HPDS), hot air dried-shrimp (HADS) and microwave vacuum-dried shrimp (MVDS). An electronic nose (E-nose) was used to obtain the aroma fingerprint of SD-BFDP samples. Headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used for qualitative and quantitative analysis of volatile compounds in SD-BFDP samples. Partial least squares regression (PLSR) was used to analyze potential correlations between sensory attributes and aroma-active compounds (AACs). Partial least squares-discrimination analysis (PLS-DA) was used to screen for signature aroma compounds. The results of the E-nose showed that there were differences in the aroma fingerprints of the SD-BFDP samples, and the E-nose could distinguish the five kinds of SD-BFDP. The qualitative and quantitative results of GC-MS showed that the types and contents of the main volatile components of SD-BFDP samples were different. 15 AACs were screened from SD-BFDP based on odor activity value (OAV). The PLSR results showed good correlations between certain sensory attributes and the majority of AACs. PLS-DA results displayed that aroma attributes of SD-BFDP samples could be distinguished by six signature aroma compounds, including trimethylamine, 2,5-dimethylpyrazine, 2-ethyl-5-methylpyrazine, nonanal, 3-ethyl-2,5-dimethylpyrazine, and octanal. These research results reveal that shrimps dried in different procedures have unique aroma characteristics, which could provide a theoretical basis for the rapid identification of aroma attributes of dried shrimps in the future. From a flavor perspective, MVD is the best drying method.

Real-Time Monitoring of the Quality Changes in Shrimp (Penaeus vannamei) with Hyperspectral Imaging Technology during Hot Air Drying

Hot air drying is the most common processing method to extend shrimp's shelf life. Real-time monitoring of moisture content, color, and texture during the drying process is important to ensure product quality. In this study, hyperspectral imaging technology was employed to acquire images of 104 shrimp samples at different drying levels. The water distribution and migration were monitored by low field magnetic resonance and the correlation between water distribution and other quality indicators were determined by Pearson correlation analysis. Then, spectra were extracted and competitive adaptive reweighting sampling was used to optimize characteristic variables. The grey-scale co-occurrence matrix and color moments were used to extract the textural and color information from the images. Subsequently, partial least squares regression and least squares support vector machine (LSSVM) models were established based on full-band spectra, characteristic spectra, image information, and fused information. For moisture, the LSSVM model based on full-band spectra performed the best, with residual predictive deviation (RPD) of 2.814. For L*, a*, b*, hardness, and elasticity, the optimal models were established by LSSVM based on fused information, with RPD of 3.292, 2.753, 3.211, 2.807, and 2.842. The study provided an in situ and real-time alternative to monitor quality changes of dried shrimps.

Insight into the Gel Properties of Antarctic Krill and Pacific White Shrimp Surimi Gels and the Feasibility of Polysaccharides as Texture Enhancers of Antarctic Krill Surimi Gels

Antarctic krill is a potential and attractive resource for consumption. However, most Antarctic krill meat is used to produce primary products with low commercial value, with few highly processed products. This study aimed to evaluate and improve the gelling properties of Antarctic krill surimi, with Pacific white shrimp surimi as control. Compared with Pacific white shrimp surimi, the lower β-sheet content and protein aggregation degree had a severe impact on the formation of the gel network of Antarctic krill surimi, which resulted in weaker breaking force, gel strength, and viscoelasticity (p < 0.05). Moreover, water retention capacity and molecular forces had a positive effect on the stability of the gel matrix of shrimp surimi. Thus, the high α-helix/β-sheet ratio, weak intermolecular interactions, and low level of protein network cross-linkage were the main reasons for the poor quality of Antarctic krill surimi. On this basis, the effects of six polysaccharides on the texture properties of Antarctic krill surimi were studied. Chitosan, konjac glucomannan, sodium carboxyl methyl cellulose, and waxy maize starch resulted in no significant improvement in the texture properties of Antarctic krill surimi (p > 0.05). However, the addition of ι-carrageenan (2%) or κ-carrageenan (1~2%) is an effective way to improve the texture properties of Antarctic krill surimi (p < 0.05). These findings will contribute to the development of reconstituted Antarctic krill surimi products with high nutritional quality and the promotion of deep-processing products of Antarctic krill meat.