Chilled Storage Research Articles

Effects of active modified atmosphere on lipid and protein oxidation, moisture migration and quality properties of beef steaks

Fresh beef is a typically perishable food because of its high water and protein content; thus, it requires proper packaging condition and storage temperature to ensure its quality. In this study, the beef steaks were stored at 4°C under HiO2 modified atmosphere packaging (MAP) (78.8% O2 + 18.8% CO2 + 2.4% N2) and HiCO2 MAP (60.0% CO2 + 40.0% N2). The traditional air packaging (AP) and vacuum packaging (VP) were used as the controls. The total viable count (TVC), colour, water holding capacity (WHC), myofibrillar protein (MP) oxidation and lipid oxidation of beef meat were investigated. The moisture distribution and migration were also analysed using the low‐field nuclear magnetic resonance (LF‐NMR). The association amongst all parameters was analysed by correlation analysis and principal component analysis (PCA). The results showed that the TVC values in the HiCO2 MAP (5.6 log CFU/g) steaks were lower than those of VP (5.9 log CFU/g), AP (7.0 log CFU/g) and HiO2 MAP (6.3 log CFU/g) steaks because of the sufficient CO2 after 15 days of chilled storage. The bright red colour and the higher WHC were maintained in the HiO2 MAP steaks than in the AP group during storage. However, higher levels of protein and lipid oxidation also occurred. The beef steaks stored under HiCO2 MAP had the lowest protein and lipid oxidation and highest value of immobile water content and WHC, however, similar to the VP group, the bright red colour was not shown. The moisture attributes (drip loss, cooking loss and P23), protein oxidation (protein solubility and carbonyl content) and lipid oxidation (TBARS value) have shown a close correlation by correlation analysis and PCA. Overall, two different packaging methods of MAP can prolong microbial‐shelf life and maintain higher WHC of beef steaks compared to AP and VP steaks, but higher oxidation level in HiO2 MAP and unattractive colour in HiCO2 MAP are concerns that need to be addressed.

The biological effect of a beef-derived Latilactobacillus sakei on beef steaks during chilled storage.

The aim of this study was to investigate the biological inhibiting effect of a beef-derived Latilactobacillus sakei (RS-25) on the spoilage of beef steaks in overwrapped packaging during the 12 days of storage at 4°C. Beef quality as well as microbial indicators were determined at different intervals during the storage after the inoculation of RS-25 at the 6 log CFU/g, and the high-throughput sequencing was applied to investigate the changes of microbial community structure during the storage. The inoculation of RS-25 on beef had no effect (p > .05) on pH, TBARS, and TVB-N during storage indicating the weak effect of such strain on the eat quality. Furthermore, the rise of L* and the delayed decline of a* and b* reveal the protection effect of RS-25 on the meat color. RS-25 reduced the re-contaminated Salmonella typhimurium by 1.16 log CFU/g (p < .01), and the growth of Brochothrix thermosphacta was also inhibited but no inhibition was found on the Pseudomonas spp. at the first 6 days of storage. The inhibiting effect of RS-25 was covered by the rapid growth of other microorganism during the following 6 days of storage. Consistent with the microbial counts results, high-throughput sequencing analysis confirmed that the inoculated L.sakei RS-25 was dominant at first 6 days, and then replaced by Pseudomonas spp. The findings obtained from the current study may provide basic information for the further application of bioprotective bacteria in preservation of beef steaks in the overwrapped packaging.

Physical and Oxidative Water-in-Oil Emulsion Stability by the Addition of Liposomes from Shrimp Waste Oil with Antioxidant and Anti-Inflammatory Properties.

Liposomes made of partially purified phospholipids (PL) from Argentine red shrimp waste oil were loaded with two antioxidant lipid co-extracts (hexane-soluble, Hx and acetone-soluble, Ac) to provide a higher content of omega-3 fatty acids. The physical properties of the liposomes were characterized by Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS) and Differential Scanning Calorimetry (DSC). The antioxidant and anti-inflammatory activity of the lipid extracts and liposomal suspensions were evaluated in terms of Superoxide and ABTS radical scavenging capacities and TNF-α inhibition. Uni-lamellar spherical liposomes (z-average ≈ 145 nm) with strong negative ζ potential (≈ -67 mV) were obtained in all cases. The high content of neutral lipids in the Hx extract caused structural changes in the bilayer membrane and decreased entrapment efficiency regarding astaxanthin and EPA + DHA contents. The liposomes loaded with the Hx/Ac extracts showed higher antioxidant and anti-inflammatory activity compared with empty liposomes. The liposomal dispersions improved the physical and oxidative stability of water-in-oil emulsions as compared with the PL extract, inducing pronounced close packing of water droplets. The liposomes decreased hydroperoxide formation in freshly made emulsions and prevented thio-barbituric acid-reactive substances (TBARS) accumulation during chilled storage. Liposomes from shrimp waste could be valuable nanocarriers and stabilizers in functional food emulsions.

Effects of Cherry (Prunus cerasus L.) Powder Addition on the Physicochemical Properties and Oxidation Stability of Jiangsu-Type Sausage during Refrigerated Storage.

Effects of different levels (1%, 3% and 5%) of cherry powder on the physiochemical properties and antioxidant activity of Jiangsu-type sausages were investigated at 4 °C for 30 days. The results show that the sensory evaluation values and physicochemical properties of the sausages had no significant differences compared to the control group when cherry powder addition was 1%, and the alcohols, aldehydes and esters were increased after the addition of cherry powder improved the flavor of sausages. However, higher concentration of cherry powder (3% and 5%) exerted adverse influences on sensory evaluation values and physicochemical properties of sausages compared with the control. The addition of cherry powder could better inhibit lipid and protein oxidation of sausages, and the cherry powder concentration has a positive correlation with its effect on the inhibition of lipid and protein oxidation. In addition, cherry powder could effectively control TVB-N values of sausages during chilled storage. All these results indicate that 1% cherry powder could not only guarantee the physicochemical properties of sausages, but also inhibited the oxidation of sausages during chilled storage.

In-situ multi-mode extraction (iMME) sampler for a wide-scope analysis of chemical and biological targets in water in urbanized and remote (off-the-grid) locations

Chemical pollution (including chemicals of emerging concern – CECs) continues to gain increasing attention as a global threat to human health and the environment, with numerous reports on the adverse and sometimes devastating effects upon ecosystems the presence of these chemicals can have. Whilst many studies have investigated presence of CECs in aquatic environments, these studies have been often focused on higher income countries, leaving significant knowledge gaps for many low-middle income countries. This study proposes a new integrated powerless, in-situ multi-mode extraction (iMME) sampler for the analysis of chemicals (105 CECs) and biological (5 genes) markers in water in contrasting settings: an urbanized Avon River in the UK and remote Olifants River in Kruger National Park in South Africa. The overarching goal was to develop a sampling device that maintains integrity of a diverse range of analytes via analyte immobilization using polymeric and glass fibre materials, without access to power supply or cold chain (continuous chilled storage) for sample transportation. Chemical analysis was achieved using ultra-performance liquid chromatography coupled with tandem mass spectrometry. Several mobile CECs showed low stability in river water, at room temperature and typical 24 h sampling/transport time. It is therefore recommended that, in the absence of cooling, environmental water samples are spiked with internal standards on site, immediately after collection and analyte immobilization option is considered, in order to allow fully quantitative analysis. iMME has proven effective in immobilization, concentration and increased stability of CECs at room temperature (and at least 7 days storage) allowing for sample collection at remote locations. The results from the River Avon and Olifants River sampling indicate that the pristine environment of Olifants catchment is largely unaffected by CECs common in the urbanized River Avon in the UK with a few exceptions: lifestyle chemicals (e.g., caffeine, nicotine and their metabolites), paracetamol and UV filters due to tourism and carbamazepine due to its persistent nature. iMME equipped with an additional gene extraction capability provides an exciting new opportunity of comprehensive biochemical profiling of aqueous samples with one powerless in-situ device. Further work is required to provide full integration of the device and comprehensive assessment of performance in both chemical and biological targets.

Comparison of different poultry egg yolks-citrate extender with green tea (Camellia sinensis) extract addition on Sapudi ram spermatozoa quality in chilled temperature storage

Preservation of ram semen has an impact on the exposure of artificial conditions to the spermatozoa which was followed by overproduction of reactive oxygen species (ROS) and resulted in functional damages of spermatozoa. This study aimed to determine the effect of the combination of chicken, quail, and duck egg yolks with green tea extract (GTE) on the quality of Sapudi ram spermatozoa at 5°C storage. Ejaculates of Sapudi ram with more than 70% spermatozoa motility were divided into four groups. Semen were extended 1 : 10 in citrated-chicken egg yolk extender (control group, T0), and citrated yolk of chicken (T1), quail (T2), and duck (T3) egg added with 0.05 mg GTE per 100 mL of extender. Extended semen was kept in a tube, which was put in a beaker containing distilled water and stored in a refrigerator (5°C). Spermatozoa motility, viability, and plasma membrane integrity (PMI) were evaluated daily for five days. The results showed that GTE in duck egg yolk citrate extender could maintain the highest spermatozoa motility, viability, and PMI for five days (p &lt;0.05). It could be concluded that the duck egg yolk citrate extender with the addition of GTE (Camellia sinensis) was beneficial for maintaining the semen of Sapudi ram spermatozoa at chilled temperatures. Further study is needed to use the extender for freezing Sapudi ram semen.

Liquid storage of Ostrich (Struthio camelus) semen at 5 °C through intermediate dilution

Dilution rate, dilution temperature and storage time have been recognized as vital steps in the processing of semen for storage before artificial insemination. The objective of this study was to determine optimal dilution and dilution temperature with an ostrich-specific semen extender for chilled storage. Four preselected ostrich (Struthio camelus var. domesticus) males, known for their ease of collection and specific semen quality parameters, were collected using the “dummy” female method. Dilution of 384 semen samples, at rates of 1:1, 1:2, 1:4 and 1:8 semen/diluent ratio with a diluent set at 5, 21 and 38 °C was performed and stored for 48 h at 5 °C. In vitro sperm function tests were conducted to evaluate treated semen during different storage intervals of 1, 5, 24 and 48 h. Motility and kinematic parameters were measured by the Sperm Class Analyzer®, the percentage live sperm measured by fluorescence SYBR14®/PI (LIVE/DEAD®), the percentage of sperm able to resist the hypo-osmotic swelling (HOS) stress test and sperm morphology determined by Nigrosin-Eosin staining. Progressive motility (PMOT), motility (MOT), sperm kinematics, LIVE and HOS were best (P < 0.05) maintained at a higher dilution of 1:4–1:8. The beneficial effect (P < 0.05) of a higher dilution temperature (21 °C) was prominent in terms of PMOT at a higher dilution. Storage of chilled semen at 5 °C requires dilution, at interpolated rates of 1:6–1:7, together with an extender temperature of 21 °C, to maintain optimal sperm function with minimal loss over a 48 h storage period.

Effect of Extender Supplemented with Date Palm Pollen Grain on Caprine Semen Qualities

Date Palm Pollen Grain (DPPG) were proved to maintain semen characteristics and quality in bulls, equines, and buffaloes. However, DPPG as supplementation in the extender for goats are scarce. Hence, the aims of this research were to investigate the semen motility and viability and to examine the functional membrane integrity of semen in different concentrations of DPPG supplemented in goat semen extenders. In this study, DPPG was added with 4% and 8% in tris-citrate-fructose-yolk (TCFY) semen extender and chilled at 5°C for 0, 24 and 48 hours. The diluted semen samples were assessed for sperm motility, viability, and membrane integrity. A total of four ejaculations from two Boer bucks were used in this study. The results indicated that the ability to maintain sperm viability was significantly higher in the extender supplemented with 8% DPPG in all storage times (P<0.05). Furthermore, 8% of DPPG in extender significantly improved sperm motility after 48 hours (56.67±5.57) compared to control (0% DPPG) (40.83±3.00) and 4% DPPG (43.33±5.24). Results also showed that sperm membrane integrity percentage in 8% DPPG (40.00±4.04) was significantly higher than control (30.33±2.19) at 0-hour storage time. The extender supplemented with 8% DPPG indicated the best result in maintaining sperm quality after 24 hours of chilled storage compared with other treatments. In conclusion, 8% of DPPG supplemented in semen extenders proved to maintain viability, motility and membrane integrity compared to control.

Effects of Plant Extracts (Clove, Fennel, Rosemary, Cinnamon, and Tea Polyphenols) on Microbiological, Chemical, and Sensory Quality of Smoke-Flavored Sea Bass during Chilled Storage

Effects of Plant Extracts (Clove, Fennel, Rosemary, Cinnamon, and Tea Polyphenols) on Microbiological, Chemical, and Sensory Quality of Smoke-Flavored Sea Bass during Chilled Storage

Slightly acidic electrolyzed water-slurry ice: shelf-life extension and quality maintenance of mackerel (Pneumatophorus japonicus) during chilled storage.

Different ice treatments were applied for the preservation of mackerel (Pneumatophorus japonicus). The quality changes of samples treated with flake ice (Control), slurry ice (SI) and slightly acidic electrolyzed water-slurry ice (SAEW-SI) in microbiological, physicochemical, protein characteristic, and sensory evaluation were investigated during chilled storage. SAEW-SI showed a significant advantage for the inhibition of microbial growth, which could extend the shelf-life for another 144 h at least, compared with Control group. SAEW-SI treatment also showed a strong inhibition for the increase in pH, total volatile basic nitrogen (TVB-N), K-value, histamine and metmyoglobin (MetMb) content. Results of texture profile analysis (TPA) and water holding capacity (WHC) indicated that SAEW-SI can obviously suppress the decrease of hardness value, and have a better protective effect on muscle structure compared to flake ice and SI (P < 0.05). During the whole experiment, the highest sensory scores and a* were obtained in the SAEW-SI group, which indicated that SAEW-SI treatment could maintain better sensory characteristics. According to the results of thiobarbituric acid reactive substances (TBARS) and fluorescence spectroscopy analysis, SAEW-SI treatment could effectively retard protein degradation and lipid oxidation compared with Control and SI group. In maintaining the quality of mackerel, SAEW-SI shows a better effect than SI due to the synergistic effect of fence factors. The results demonstrated that the shelf-life of mackerel could be extended and the quality of mackerel could be maintained effectively with SAEW-SI treatment during chilled storage. © 2022 Society of Chemical Industry.

Effect of Procyanidin on Canine Sperm Quality during Chilled Storage.

Procyanidin (PC) is a polyphenolic compound with antioxidant activity. The purpose of this study was to determine the influence of PC on canine sperm quality after 72 h of storage at 4 °C. The collected ejaculates were separated into four equal aliquots and treated with various concentrations of PC (0, 10, 30, and 50 μg/mL) in Tris-citric-fructose-egg yolk (TCFE) extender and stored at 4 °C for 72 h. The findings revealed that 30 μg/mL PC was the optimum concentration for significantly improving sperm motility (p &lt; 0.05). Sperm samples treated with 30 μg/mL PC had substantially greater plasma membrane integrity, acrosome integrity, and mitochondrial membrane potential than the control group (p &lt; 0.05). Furthermore, T-AOC and the expression levels of superoxide dismutase 1 (SOD1), catalase (CAT), and glutathione peroxidase 1 (GPx1) genes were significantly higher in sperm treated with 30 μg/mL PC than those in control (p &lt; 0.05). In summary, this study discovered that adding PC to the TCFE extender enhanced sperm quality and that 30 μg/mL PC was the optimal concentration for canine sperm when stored at 4 °C.

Antioxidant, Antimicrobial and Physicochemical Properties of Beef Sausages Enriched with an Aqueous Extract of Senduduk (Melastoma malabathricum L.) Leaf

The use of natural products in sausages has become a new trend for health reasons. A natural product that could be incorporated into sausages is an extract of the senduduk (Melastoma malabathricum L.) leaf. Senduduk is an abundant shrub herb in Indonesia. This kind of plant is mostly used as a traditional medical remedy and as an ingredient in some culinary recipes. This study was carried out to investigate the effect of an aqueous extract of senduduk leaf (SLE) on the antioxidant, antimicrobial and physicochemical properties of beef sausage. Four treatments were used: ingredients consisting of beef, vegetable oil, skim milk, tapioca, salt, phosphate, ice cubic, garlic, pepper, dan nutmeg as a Control; the Control ingredients plus 0.01% of butylated hydroxytoluene (BHT); the Control ingredients plus 0.83% of SLE (SLE-1), and the Control ingredients plus 1.1% of SLE (SLE-2). All ingredients of each formula were homogenously blended and the sausage mix was cooked. The addition of BHT and SLE affected the proximate composition, with the moisture content decreasing as the duration of chilled storage increased. The addition of SLE lowered the pH and aw value and both tended to increase during chilled storage. SLE also enhanced the WHC of the sausages which increased in value during chilled storage. The addition of BHT and SLE could increase the antioxidant activity of the sausages as indicated by scavenging DPPH free radicals. SLE in sausages could inhibit microbial growth during chilled storage. It can be summarized that the addition of an aqueous extract of senduduk could improve the physicochemical, antioxidant and antimicrobial properties of beef sausages.

The Impact of Raw Milk Quality, particularly Thermoduric, and Storage Temperatures on the Keeping Quality of Pasteurized Milk

Abstract This study was aimed to investigate the effect of raw milk qualities on their corresponding pasteurized milk stored at different chilled temperatures. Raw milk collected from two different sources, Banhong (BH) milk farm and Mae Tha (MT) collection center, were pasteurized at 78 ± 2ºC for 30 s and kept for 21 days at 4-8ºC. During the storage period, representatives of milk treatments were assessed for their chemical, microbiological and sensorial characteristics. Collected data revealed that there was only minor alteration for the chemical properties of pasteurized milk throughout the studied storage period. The microorganism numbers in the pasteurized milk were significantly increased during storage and higher at higher storage temperatures. Poorer microbial quality of raw milk, including thermoduric bacteria, strongly contributed to higher microbial load of the correspondence pasteurized milk during chilled storage. The coliform number of all the pasteurized milk samples was found to be below 1 cfu/ml during 21 days of storage, while no Escherichia coli, Listeria monocytogenes and Staphylococcus aureus was detected in the pasteurized milk samples. The appraisal of the sensory features of pasteurized milk, including color, flavor, odor, creamy taste, texture and overall acceptance, were gradually decreased with longer storage period. Keywords: Pasteurized milk, Storage temperatures, Raw milk, Microbial quality, Chemical properties

Cold-induced denaturation of muscle proteins in hairtail (Trichiurus lepturus) during storage: Physicochemical and label-free based proteomics analyses.

Physicochemical, proteomics, and bioinformatics analyses were conducted to investigate protein profiles in Trichiurus haumela under frozen (120 d) and chilled (6 d) storage. Springiness, chewiness, myofibrillar active sulfhydryl content, and Ca2+-ATPase activity significantly decreased, suggesting that cold stress altered muscle proteins. Compared with fresh hairtail (FH), 66 common differentially abundant proteins (DAPs) had lower abundances in chilled (3 d; CSH) and frozen (120 d; FSH) hairtail, including myosin binding proteins, filamins, actinin, troponin, and muscle-restricted coiled-coil protein. Gene Ontology (GO) annotation showed DAPs were mainly involved in cellular process, cellular anatomical entity, intracellular, and binding items. Eukaryotic orthologous group (KOG) analysis revealed that changes in cytoskeleton and energy production and conversion functions dominated during cold storage, degrading the myofibril and connective tissue structures and the physicochemical performance of muscle tissues. This study presents deep insights into the protein alternation mechanisms in hairtail muscle under cold stress.

A TMT-based proteomic approach for investigating the effect of electron beam irradiation on the textural profiles of Litopenaeus vannamei during chilled storage

To elucidate the effect of electron beam irradiation (EBI) on the textural quality of Litopenaeus vannamei, the tandem-mass-tag labeled proteomic method was conducted to illustrate the protein changes in shrimp muscle. The results suggested that shrimp irradiated with 5 kGy exhibited optimum textural traits of hardness, springiness, and chewiness. In total, 486 proteins were identified as differentially abundance proteins (DAPs) in multiple comparison groups. Bioinformatics analysis revealed that most of DAPs participated in cellular process, binding, and catalytic. etc. Various signaling pathways, such as RNA transport and oxidative phosphorylation, were notably enriched by DAPs. The correlation analysis indicated that some DAPs such as Myosin-XVIIIa, projectin, and beta-thymosin 3 were remarkably correlated with the textural properties, which could be proposed as potential biomarkers to assess the irradiation-induced textural variation in shrimp. This study provided an insightful understanding at the protein level to improve the application of EBI to shrimp preservation.

Effects of hot or cold boning on the freshness and bacterial community changes of lamb cuts during chilled storage

Deboning methods are vital during fresh meat processing, influencing the evolution of spoilage. In this study, we examined the effects of deboning methods (including hot boning (HB), conventional chilling and boning (CCB) and very fast chilling and boning (VFCB)) on freshness and bacterial changes of lamb cuts stored at 4 °C. The freshness of lamb was evaluated by total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), total viable count mesophilic (TVCm) and total viable count psychrophilic (TVCp), and the bacterial community was determined by 16S rRNA high-throughput sequencing. The results showed basically no significant difference in the freshness indicators between HB and CCB lamb, and those of VFCB lamb were significantly lower than HB and CCB lamb except TBARS. In the early and mid storage, Pseudomonas and Ralstonia were dominant in HB lamb and norank_f_Mitochondria was dominant in CCB and VFCB lamb. In the end of storage, Pseudomonas was dominant in all lambs. Furthermore, the nutrient metabolism and some pathways potentially involved in cellular interaction might be prominent during lamb spoilage. Our work can provide information for delaying spoilage and supporting the high-quality development of raw lamb.

The efficiency of citrus peel powders in improvement of meat quality during chilled storage

The efficiency of citrus peel powders in improvement of meat quality during chilled storage

A Review on Performance of Solar Powered Air Conditioning System

Abstract: Solar energy converts the renewable energy to increase growth. The development of energy in to generated worldwide. It in the most easy to construct the process of solar air Conditioning systems. The different energy areinvolved into the solar air conditioning to the decreasing current Sources Then using high oil and concern environmental effects have been Controlling. The most comfortable Process of the solar energy system. It we implemented nowadays, increase in progress. we are air Conditioning systems are using in. every building, malls,Colleges industries, flats, etc. solar power air conditioning system is the hot issue to study building energy Consumer. I Then we indoor and outdoor comfort of air Conditioning while be cold storage system. To increasing the efficiency of air Conditioning intensity of the cooling system. The transient thermal efficiency we can using the storage system to maintain the temperature to indoor,The solar system must be using the different. Parabolic collector from the high accommodation,The basic analysis, to investment of Solar air conditioning system are using 3-phase accumulator. The solar energy using of high rate of low grade energy to high grade of energy are Converting them. It will high efficient process could be panels, collectors, will cool the High temperature can be assumed to use the chilled water storage tank. can be provided due to reduce the system of on and off options. There are improving solar system.It will high efficient process could be panels , collectors, will cool the High temperature can be assumed to use the chilled water storage tank. can be provided due to reduce the system of on and off options. There are improving solar system.it is common for the storage chilling water can be utilized, that can to be operated solar energy.

Investigating the microbial inactivation effect of low temperature high pressure carbon dioxide and its application in frozen prawn (Penaeus vannamei).

During the pandemic of coronavirus disease 2019, the fact that frozen foods can carry the relevant virus raises concerns about the microbial safety of cold-chain foods. As a non-thermal processing technology, high pressure carbon dioxide (HPCD) is a potential method to reduce microbial load on cold-chain foods. In this study, we explored the microbial inactivation of low temperature (5-10 °C) HPCD (LT-HPCD) and evaluated its effect on the quality of prawn during freeze-chilled and frozen storage. LT-HPCD treatment at 6.5 MPa and 10 °C for 15 min could effectively inactivate E. coli (99.45%) and S. aureus (94.6%) suspended in 0.85% NaCl, SARS-CoV-2 Spike pseudovirus (>99%) and human coronavirus 229E (hCoV-229E) (>1-log virus tilter reduction) suspended in DMEM medium. The inactivation effect of LT-HPCD was weakened but still significant when the microorganisms were inoculated on the surface of food or package. LT-HPCD treatment at 6.5 MPa and 10 °C for 15 min achieved about 60% inactivation of total aerobic count while could maintain frozen state and quality of prawn. Moreover, LT-HPCD treated prawn exhibited significant slower microbial proliferation and no occurrence of melanosis compared with the untreated samples during chilled storage. A comprehensive quality investigation indicated that LT-HPCD treatment could maintain the color, texture and sensory of prawn during chilled or frozen storage. Consequently, LT-HPCD could improve the microbial safety of frozen prawn while maintaining its original quality, and could be a potential method for food industry to improve the microbial safety of cold-chain foods.

Effect of chitosan-epigallocatechin gallate coating on volatile flavor compounds retention in bighead carp (Aristichthys nobilis) fillets during chilled storage

The effects of chitosan-epigallocatechin gallate (EGCG) coating on sensory properties and retention of volatile flavor compounds (VFCs) in chilled bighead carp fillets were examined. Scores of odor and overall acceptability indicated that as compared with the control group and group coated with chitosan, chitosan-EGCG coating had the best retention effect on the flavor and quality of the fillets. Twenty-eight VFCs, mainly alcohols, ketones, and aldehydes, were identified from the fillets by GC-IMS analysis. Fillets in the control group showed unique characteristic VFCs distribution at different storage stages: 2-butanone in the early stage; 3-methylbutanal and 2-methylbutanal in the middle stage; and heptanal and 1-octen-3-ol in the final stage. However, the VFCs signals in chitosan-EGCG coated fillets were delayed along with the sharply suppressed intensities of off-odor VFCs such as 1-octen-3-ol, indicating that chitosan-EGCG coating was able to inhibit the formation of off-odors effectively. Principal component analysis and clustering analysis distinguished samples with different storage times and treatments. This study indicated that chitosan-EGCG coating could maintain the flavor quality of bighead carp fillets, and the characteristic VFCs of different storage stages could be considered as signal indicators to identify fish freshness.