Lower Total Volatile Basic Nitrogen Research Articles

Preparation, characterization, and coating effect of bio-active nano-emulsion based on combined plant essential oils on quality of grass carp fillets

This study aimed to develop a satisfactory essential oil (EO) nano-emulsion through high pressure microjet technology and explore its physiochemical properties and synergistic coating effects on grass carp fillets. The optimal conditions for oregano/litsea cubeba (6:4, wt%/wt%) nano-emulsion were shown to be 80 s high pressure microjet pretreatment time, 9000 lb per square inch pretreatment pressure, 6 % oil phase, and 3:2 Km (mass ratio of surfactant to co-surfactant). The obtained nano-emulsion exhibited 100.42 ± 0.96 nm oil diameter at 4 °C after 15-day storage, coupled with high stability after centrifugation, freeze–thaw and heating treatment. Compared with untreated samples at day 6 storage, the nano-emulsion-treated grass carp fillets exhibited improved textural properties, higher water-holding capacity (74.23 % ± 0.80 %), lower total volatile basic nitrogen (TVB-N, 13.46 ± 0.30 mg/100g)/thiobaric acid (TBA,0.43 ± 0.02 mgMDA/100g), and lower total viable spoilage bacteria count (4.98 ± 0.21 lgCFU/g). This study facilitates understanding the combined EOs nano-emulsion on improving the shelf life of grass carp fillets.

Protection of Whey Polypeptide on the Lipid Oxidation, Color, and Textural Stability of Frozen-Thawed Spanish Mackerel Surimi.

Repeated freeze-thaw (FT) cycles can have an impact on surimi quality. In this study, we used 0.02% BHA as a positive control group. We examined the effects of different concentrations (0%, 5%, 10%, and 15%) of whey protein hydrolysate (WPH) on surimi, focusing on alterations in color metrics (L* for brightness, a* for red-green, b* for yellow-blue, and overall whiteness), textural characteristics, and antioxidant capacity during various freeze-thaw (FT) cycles. The results showed that the lipid oxidant values of surimi, as well as its a* and b* values, rose as the number of FT cycles increased; whereas the adhesiveness, resilience, gumminess, and shear force dropped, as did L* and the whiteness values, leading to an overall darkening of color and gloss. By contrast, the study found that the addition of WPH could effectively slow down the decrease of surimi textural stability after repeated freeze-thawing, with the textural stability of the group with 15% WPH being significantly superior to those of the other groups (p < 0.05). Under the same number of cycles, adding 15% WPH to the experimental group could successfully lower total volatile basic nitrogen (TVB-N) and effectively increase the antioxidant activity of surimi. This finding suggested that 15% WPH had the greatest effect on increasing surimi FT stability. To conclude, it was proved that WPH can be added to frozen surimi and improve its quality.

Impact of supercooling storage on physical and chemical properties of yellowfin tuna (Thunnus albacares)

Seafood is highly perishable, and its spoilage begins immediately after harvesting due to the production of various metabolites. However, freezing, a conventional long-term preservation technology, causes quality degradation due to ice crystallization. Supercooling has emerged as a promising technique to prevent ice formation and quality degradation. In this study, tuna fillets were supercooled at −3.5 °C with an external pulsed electric field (PEF) and oscillating magnetic field (OMF) strengths for optimization. Quality factors such as drip loss, color, microbial analysis, texture, and total volatile basic nitrogen (TVB-N) were evaluated in comparison with refrigerated, frozen-thawed, and supercooled samples stored for 1, 4, 7, and 10 days. The results showed that supercooled samples had lower TVB-N values than refrigerated samples. The aerobic plate counts of supercooled tuna samples did not significantly vary from 1 to 7 days of storage. Moreover, supercooling preserved the textural integrity of the product and reduced drip loss compared to frozen-thawed samples. Therefore, supercooling preservation can extend the shelf-life of tuna fillets while minimizing quality degradation, indicating its potential compared to conventional refrigeration and freezing methods.

Effect of gum tragacanth–sodium alginate coatings incorporated with epigallocatechin gallate on the quality and shelf life of large yellow croaker (Larimichthys crocea) during superchilling storage

Abstract The effect of gum tragacanth (GT) and sodium alginate (SA) active coatings incorporated with epigallocatechin gallate (EGCG; 0.16%, 0.32%, and 0.64%, respectively) on the quality of large yellow croaker fillets was evaluated during superchilling storage at –3 ˚C for 42 d. The results revealed that the GT-SA-EGCG active coatings delayed microbial spoilage by reducing the total viable counts of Pseudomonas spp. and psychrophile bacteria and retarded the degradation of the physical properties of water-holding capacity, cooking loss, color, odor and texture. GT-SA-EGCG coatings could also maintain fillet freshness by maintaining lower total volatile basic nitrogen, K value, and histidine content, inhibiting myofibrillar protein degradation during superchilling storage. These results suggested that the active coatings embedded with GT-SA-EGCG could be used as a preservative to enhance the quality of large yellow croaker and prolong the shelf life by 7–14 d during superchilling storage at –3 ˚C.

Enhancement of foaming properties and storage stability of pasteurized liquid egg white through ultrasound modification

Due to the high heat sensitivity of liquid egg white (LEW), there were a loss of foaming properties during pasteurization. At the same time, the temperature of pasteurization was limited by this property and did not limit the growth of microorganisms very well. Therefore, the article hoped to improve the foaming characteristics of pasteurized liquid egg white (PLEW) and to increase the stability during storage by using water-bath ultrasound. It was found that the foaming capacity of the pasteurization only group increased from 270% to 326% under optimal sonication conditions (60 Hz, 400 W, 15 min). The increase in protein solubility and decrease in particle size following ultrasound suggested that ultrasound had a deaggregation effect. The fact that surface tension was reduced suggested that sonication could provide more soluble proteins and a more flexible conformation for PLEW. Both free sulfhydryl and surface hydrophobicity were enhanced, which might be related to the disruption of protein molecular forces by the cavitation effect of ultrasound. The results of spectral analysis again revealed that the essence of ultrasound to improve the foaming properties of PLEW lied in changing the conformation of the protein molecule. Furthermore, the results also demonstrated that the ultrasound-treated LEW showed better foaming properties, minimal changes in viscosity, lower total volatile basic nitrogen content, and a longer shelf life (40 d) during storage. The quality of the ultrasound-treated group remained the most stable. Therefore, ultrasound has great potential for improving the foaming ability and stability of PLEW.

Stunning methods before slaughter induce oxidation changes of large yellow croaker during cold storage: the role of mitochondria and underlying mechanisms.

Improper stunning methods before slaughter could cause fish to deteriorate more quickly during cold storage. However, it is unclear how stunning methods affect the mitochondrial structure and the role of mitochondria in oxidation in muscle-based food. This study explored the potential mechanism of oxidation induced by different stunning methods (hit on the head, T1 ; gill cut, T2 ; immersion in ice/water slurry, T3 ; CO2 asphyxiated, T4 ; 40% CO2 + 30% N2 + 30% O2 , T5 ) in large yellow croaker during cold storage. The results showed that T4 samples had the minimum stress response and the mitochondrial membrane potential and permeability were less damaged. Besides, the mitochondrial functional structure and peroxisome of T4 samples were less damaged compared with other samples, which was reflected in higher total superoxide dismutase, catalase and glutathione peroxidase activities. In terms of oxidation indices, the T4 samples showed higher pH values and iron myoglobin contents and lower total volatile basic nitrogen and thiobarbituric acid reactive substances after 168 h cold storage, indicating that the T4 samples significantly maintained oxidative stability of large yellow croaker. The CO2 asphyxiation had the least oxidative damage to large yellow croaker during cold storage, possibly because it had the least effect on mitochondrial structure, reactive oxygen species and antioxidant enzyme activity. © 2023 Society of Chemical Industry.

Effect of Slightly Acidic Electrolyzed Water Immersion at Different Frequencies on Quality of Raw Chicken Legs.

Slightly acidic electrolyzed water (SAEW) is used as a disinfectant for raw chicken meat. Because its volume for a single immersion exceeds 10 times the weight of meat, a large amount of wastewater is generated. Importantly, a higher frequency of immersion is believed to reduce microbial contamination. The objective of this study was to investigate the effect of SAEW immersion at different frequencies on the disinfection and quality of raw chicken legs, thereby possibly limiting the usage of SAEW. Immersion for 1, 3, and 5 times, with a 7:1 SAEW:meat ratio, and duration of 15 min was tested. Meat quality was evaluated based on total aerobic bacteria, Enterobactericeae, total volatile basic nitrogen, thiobarbituric acid reactive substances, and color. A higher immersion frequency lowered the numbers of total aerobic bacteria and Enterobacteriaceae. Moreover, two immersions with a SAEW:meat ratio of 4:1 and a total immersion time of 6 min reduced the bacterial load as effectively as a single 15-min immersion with a SAEW:meat ratio of 7:1. Higher frequencies of SAEW immersion also resulted in lower total volatile basic nitrogen and lipid oxidation after 0 or 3 days of storage. They did, however, magnify the change in color, resulting in brighter meat. Overall, SAEW treatments with two to five immersions can improve the quality of raw chicken legs and reduce wastewater generation.

Hydrogels, Oleogels and Bigels as Edible Coatings of Sardine Fillets and Delivery Systems of Rosemary Extract.

Edible coatings provide an alternative way to reduce packaging requirements and extend the shelf life of foods by delaying oxidation and microbial spoilage. Hydrogels, oleogels and bigels were applied as coatings on fresh sardine fillets. The effectiveness of these coatings as delivery systems of rosemary extract (RE) was also evaluated. Three groups of sardine fillet treatments were prepared: (i) the control (C), which comprised sardine fillets without coating, (ii) sardine fillets with plain hydrogel (H), oleogel (O) or bigel (BG) coatings, and (iii) sardine fillets with RE incorporated into the H, O and BG coatings. The different treatments were evaluated for lipid oxidation (TBA test), total volatile basic nitrogen (TVB-N) and microbiological growth during cold storage at 4 °C. Results showed that hydrogel, oleogel and bigel coatings delayed oxidation. The incorporation of RE into coatings significantly retarded lipid oxidation but did not affect the proliferation of microorganisms during storage. When RE was incorporated in the oleogel phase of the bigel coating, it produced significantly lower TVB-N values compared to the control and BG treatments. The incorporation of RE into the oleogel phase of the bigel coating may be a promising method of maintaining the storage quality of the sardine fillets stored at refrigerated temperatures.

Effects of chitosan molecular weight and deacetylation degree on the properties of collagen‐chitosan composite films for food packaging

AbstractComposite films based on collagen and chitosan with different molecular weights (MWs) and deacetylation degree (DD) are prepared for food packaging. Fourier‐transform infrared analysis indicates that more hydrogen bonds have formed between collagen molecules and chitosan with larger MW or higher DD due to their more reactive groups for interactions. The light barrier capacity, mechanical, and thermal properties of the composite films enhanced with increasing the MW or DD of chitosan. However, composite film with the lowest MW of 50 kDa possesses the best antioxidative and antibacterial activities. Among all the films, composite films containing chitosan with low MW of 50 kDa and high DD of 95% exhibit better preservation effect in pork. The shelf life of pork wrapped with film containing chitosan of 50 kDa has been extended to 3 days with the lowest total volatile basic nitrogen level (12.13 mg/100 g), thiobarbituric acid reactive substance value (0.541 mg malondialdehyde/kg) and total viable count (5.64 log colony forming unit/g). These results indicate that MW and DD of chitosan are two important factors that should be considered when designing collagen‐chitosan composite films for food packaging.

The effects of different packaging methods and sous vide cooking on chemical, sensory, and microbiological changes of marinated crayfish ( Astacus leptodactylus Esch., 1823)

Chemical, sensory parameters and microbiological condition of marinated crayfish (Astacus leptodactylus), with emphasis on the quality and safety parameters in brine, vacuum packaging (VP) and sous-vide cooking were investigated. Quality assessment of crayfish stored in in brine, vacuum packaging (VP) and sous-vide (SV) for up to 120 days at 4±1 °C was done by the monitoring of sensory, microbiological, pH value, total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA) and peroxide value (PV). The highest concentration of TVB-N was recorded in the marinated crayfish stored under brine whereas the lowest TVB-N in the marinated crayfish stored under SV packed conditions. The concentration of TBA increased and its level reached over 5.44 mg MA/kg for crayfish stored in brine, 3.57 mg MA/kg for VP and 2.54 mg MA/kg for SV at 120 days. The formation of PV increased with the time of storage and was the lowest in the marinated crayfish stored in SV packed. During storage period, aerobic and anaerobic colony count, Escherichia coli, Coagulase positive staphylococcus, Listeria monocytogenes, Salmonella, and Clostridium perfringens were not found in any of samples. The marinated crayfish packed in sous-vide had extended shelf life at 4±1 °C compared to that packaged in brine and VP according to physico-chemical analysis.

Effect of detoxified Rhus verniciflua extract on oxidative stability and quality improvement of raw chicken breast during cold storage.

This study investigated the utilization of detoxified Rhus verniciflua (RV) extract as a natural antioxidant to extend the shelf life of chicken breast meat during storage. Pre-heating at (35°C, 100°C, 120°C, and 140°C) was conducted on heartwood of RV prior to extraction to improve its antioxidant activity and remove the allergenic compound urushiol. The antioxidant activity was the highest when RV pre-heated at 120°C with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging activity observed at 62.29 EC50 µg/mL and 12.11 IC50 mg/mL, respectively. Pre-heating also significantly increased the total phenolic content (TPC), with the highest improvement was seen at 120°C, 100°C, and 140°C respectively, wherein 35°C shared no difference with the raw RV (RRV). Urushiol content was vanished following pre-heating at 120°C and 140°C. With respect to these result, pre-heating treatment at 120°C was applied before the extraction of the heartwood of RV. Prepared breast meat sample was dipped into distilled water as a negative control, 0.02% butylated hydroxytoluene (BHT) as positive control, and a solution containing detoxified RV extract (0.10%, 0.25%, 0.50%, 1.00%) at 4°C for 60 min. Treatment group with 0.50% and 1.00% addition increased the redness and yellowness value on day 6 and day 3 of storage respectively (p < 0.05). The pH value of breast meat was also increased in treatment of 0.50% and 1.00% on day 0, but subsequently lower until end of storge day compared to control negative (p < 0.05). Furthermore, 0.50% treatment exhibited a higher antioxidant activity, stronger inhibition of the microbial growth evaluated by total viable count and maintaining a lower total volatile basic nitrogen among treatments (p < 0.05), unless for BHT and 1.00% treatment groups (p > 0.05). It indicates a similar efficacy of detoxified RV extract with that of positive control treated with BHT. The results of this study suggested that dipping chicken breast meat into a solution containing 0.50% of previously pre-heated RV heartwood at 120°C could be a promising natural antioxidant for extending the shelf life, and at the same time improve its quality during storage.

Evaluating the effect of an emerging microwave-assisted induction heating (MAIH) on the quality and shelf life of prepackaged Pacific white shrimp Litopenaeus vannamei stored at 4°C in Taiwan

Microwave-assisted induction heating (MAIH) is an emerging alternative technology for shrimp cooking over traditional heating technologies. This study evaluated the effect of the MAIH and boiling in salt solution on the quality and shelf life of prepackaged Pacific white shrimp L . vannamei stored at 4 °C in Taiwan. Samples were treated for 80 s at 130 °C or for 100 s at 90 °C with the MAIH technology, and 130 s at 90 °C with boiling in salt solution, respectively. Cooked shrimps were stored 28 days at 4 °C to determine changes in aerobic plate count (APC), psychrotrophic bacteria count (PBC), color, texture, pH, and total volatile basic nitrogen (TVBN). Results showed that the levels of APC and PBC were not detectable (<2.0 log CFU/g) during first 12 days of storage in samples treated with the MAIH technology, but they slowly increased afterward, reaching to 3.0 log CFU/g on the 28th day of storage, compared to the traditional boiling technology, when the levels of APC and PBC were gradually increased throughout 28 days of storage, exceeding 8.7 log CFU/g at the end of the storage. In terms of color and TVBN, all cooked samples showed a decreasing trend in lightness ( L* ), redness ( a* ), and whiteness ( W ) but an increasing trend in yellowness ( b* ), absolute color difference ( ΔE ), and the TVBN during the storage period. However, these decreasing and increasing trends occurred slower in samples treated by the MAIH than by boiling ( p < 0.05). In terms of texture, samples treated by the MAIH demonstrated greater hardness and cohesiveness during the storage than samples boiled in salt solution ( p < 0.05). Compared with traditional boiling method, the treatment of shrimp samples with the MAIH delayed the degradation of color and texture and inhibited the growth of microorganisms during refrigerated storage. Therefore, the MAIH technology offers a potential alternative over boiling method for preventing the deterioration and quality loss of shrimps more effectively and extending the refrigerated shelf life of prepackaged Pacific white shrimps stored at 4 °C. • Effect of MAIH and boiled heating on quality of shrimp stored at 4 °C were evaluated. • The MAIH effectively pasteurized and retarded bacterial growth of shrimp until 12 d. • The boiled samples had higher aerobic plate counts and lower physicochemical values. • MAIH can delay reduction of color ( L* , a* , W ) and hardness in samples during storage. . • Shrimps heated by MAIH maintained lower TVBN and extended shelf life from 8 d to 28 d .

Effect of multi-frequency ultrasound assisted thawing on the quality of large yellow croaker (Larimichthys crocea)

The effects of mono-, dual- and tri-frequency ultrasound-assisted thawing (UAT) on the physicochemical quality, water-holding capacity, moisture migration and distribution and myofibrillary structure of frozen large yellow croaker (Larimichthys crocea) were detected. The results indicated that multifrequency UAT treatment significantly increased the thawing rate, maintained the stability of myofibrils and reduced the lipid oxidation. The multifrequency UAT samples had better water-holding capacity (higher water-holding capacity values, lower thawing loss and cooking loss) and physicochemical quality (higher hardness, springiness, resilience, chewiness and lower total volatile basic nitrogen (TVB-N) values, thiobarbituric acid reactive substances (TBARS) values), higher immobilized water content, and lower free water content. Therefore, the results provide a further understanding of the quality stability of frozen large yellow croaker treated by the multifrequency UAT.

Influence of Multifrequency Ultrasound-Assisted Freezing on the Flavour Attributes and Myofibrillar Protein Characteristics of Cultured Large Yellow Croaker (Larimichthys crocea).

The influence of multifrequency ultrasound-assisted freezing (UAF) as compared with single- and dual-UAF on the flavour, microstructure, and myofibrillar proteins (MPs) of cultured large yellow croaker was investigated to improve food quality in a sustainable way and address the major global challenges concerning food and nutrition security in the (near) future. Multifrequency UAF-treated samples had lower total volatile basic nitrogen values during freezing than single- and dual-UAF-treated samples. Thirty-six volatile compounds were identified by solid-phase microextraction (SPME) coupled to gas chromatography–mass spectrometry (GC-MS) during freezing, and the multifrequency UAF-treated samples showed significant decreases in the relative contents of fishy flavoured compounds, including 1-penten-3-ol and 1-octen-3-ol. In addition, multifrequency UAF treatment better maintained a well-organised protein secondary structure by maintaining higher α-helical and β-sheet contents and stabilising the tertiary structure. Scanning electron microscopy images indicated that the ice crystals developed by the multifrequency UAF were fine and uniformly distributed, resulting in less damage to the frozen large yellow croaker samples. Therefore, multifrequency UAF improved the flavour attributes and MP characteristics of the large yellow croaker samples. Overall, multifrequency UAF can serve as an efficient way for improving food quality and nutritional profile in a sustainable way.

An active packaging film based on esterified starch with Tartary buckwheat bran extract and chitosan and its application for mutton preservation

An active film based on esterified starch incorporating Tartary buckwheat bran extract and chitosan was prepared for mutton preservation, and the effect of these active films on the freshness and edible quality of chilled mutton meats at 4 ± 1°C for 11 days was studied. The physical and antioxidant properties of the films were analyzed. Next, the meat quality changes in mutton packaged with the active film and control samples were studied. Compared with the control samples, mutton packaged with the active film demonstrated a lower pH increase as well as lower total volatile basic nitrogen and thiobarbituric acid reactive substance contents over the whole storage period. The results indicated that the storage time of mutton were increased by 2 days at 4 ± 1°C. In conclusion, active films containing Tartary buckwheat bran extract and chitosan can maintain the quality of mutton. Practical applications Reasonable packaging provides a final barrier to prevent spoilage effectively. Esterified starch and chitosan can enhance the physical and chemical properties of active packaging films. Here, we created an active film via casting and including Tartary buckwheat bran extract with esterified starch and chitosan. It can be prepared in not only the laboratory but also the factory. Moreover, the mechanical, optical, and antioxidant properties of our active films and their actual preservation effect were explored. The comprehensive characteristics of our films provide valuable information for practical applications.

USE OF GALACTOMANNAN FROM Caesalpinia pulcherrima IN RESTRUCTURED FISH PRODUCTS STORED UNDER FROZEN CONDITIONS

ABSTRACT The objective of this work was to evaluate the use of galactomannan from Caesalpinia pulcherrima as a binding agent for the restructuring of fishes. The effect of a frozen (-18 °C) storage of 120 days on the physical-chemical and mechanical properties of fishes was evaluated, restructured fish products with transglutaminase were used as a control. Two fish restructuring formulations were developed: Galactomannan, with 0.2% galactomannan and 1.8% refined salt; and Control, with 0.5% transglutaminase. The analyses were carried out after 24 hours of refrigerated storage (4 °C), corresponding to time zero, and after 30, 60, 90, and 120 days of frozen (-18 °C) storage. The use of galactomannan resulted in a higher pH, and lower total volatile basic nitrogen (TVB-N) and thiobarbituric acid reactive substances (TBARS), with no differences from zero to 120-day storage times for the L*, a*, and b* coordinates. Galactomannan easily bounds to hydrogen, enabling the obtaining restructured fish products with lower expressible water content and less weight losses by cooking, important characteristics for the acceptance of products that denote softness and succulence. Contrastingly, this easy bound to water molecules resulted in a lower hardness, cohesiveness, and elasticity, and higher adhesivity when compared to the control. The results showed the viability of using galactomannan to restructure fishes during frozen storage.

Development of chitosan films incorporated with rambutan (Nephelium lappaceum L.) peel extract and their application in pork preservation

Chitosan (CS) films containing 0, 1, 3 and 5% (w/w) of polyphenol-rich rambutan peel extract (RPE) were developed. The micro-structural characterization and physical and functional properties of the films were determined. Results showed RPE formed strong interactions with CS, making film inner micro-structure become uniform and film crystallinity decline. Amongst different films, CS film containing 5% of RPE showed the lowest light transmission, moisture content (28.35%), water solubility (46.07%), water vapor permeability (8.41 × 10−10 g m−1 s−1 Pa−1) and oxygen permeability (0.28 cm3 mm m−2 day−1 atm−1). Meanwhile, CS film containing 5% of RPE exhibited the highest tensile strength (38.87 MPa) and elongation at break (51.73%) and the strongest antioxidant and antimicrobial activities. Finally, pork was wrapped with the films and stored at 4 °C for 8 days. Results showed pork wrapped with CS film containing 5% of RPE presented the lowest total volatile basic nitrogen level (9.17 mg/100 g), thiobarbituric acid reactive substance value (0.51 mg malondialdehyde/kg) and total viable count (4.53 log colony forming unit/g) and the best sensory attributes on the eighth day. Our results suggested the potential of CS film containing 5% of RPE as an active packaging material in pork preservation.

Effects of acid and alkaline treatments on physicochemical and rheological properties of tilapia surimi prepared by pH shift method during cold storage

Microbial, physicochemical, rheological, and microstructural changes of surimi prepared by pH shift methods and the traditional water-washing method during cold storage were investigated. The starting aerobic mesophilic count (AMC) of pH shift surimi was around 1 log CFU/g lower than water-washed surimi, suggesting antimicrobial effects of the pH shift. All samples could be stored for 5 to 6 days based on the AMC results. Throughout the storage, the gel strength of alkaline-treated surimi increased from 204.2 to 491.9 g, while water-washed surimi decreased from 462.1 to 172.9 g. After the storage, alkaline-treated surimi showed lower total volatile basic nitrogen (TVB-N) value and smaller network hole size that was suitable for incorporation of moisture and starch. It also remained its rheological properties comparing with acid-treated surimi, with better odour properties, less protein degradation, and better network formation. The results indicate that alkaline-treated surimi is more suitable for cold storage.

Application of Black Cumin and Green Tea Extracts and Oils for Microbiological, Physicochemical, Textural and Sensorial Quality of Vacuum Packaged Rainbow Trout Fillets Stored at 2±1°C

ABSTRACT The study was conducted to evaluate the effect of black cumin extract (BCD), green tea extract (GTD), black cumin oil (BCO), and green tea oil (GTO) (10%) on the proximate, microbial, physicochemical, textural, and sensorial quality of vacuum packaged rainbow trout during 16 days of storage at 2 ± 1°C. Results indicated that both BCD and BCO had significant effects on reduction of bacterial growth. Thiobarbituric acid (TBA) values (0.21–0.48 mg MA/kg) of all groups at the end of storage did not exceed the limit values. The BCD and BCO showed lower total volatile basic nitrogen (TVB-N) values than control, GTD, and GTO during storage, and TVB-N limit value was exceeded on the 11th day in the CO, GTD, and GTO, and on the 16th day in the BCD and BCO. During the research, pH and water activity of trout fillets ranged between 6.03–6.34 and 0.9863–0.9942, respectively. The results also showed that the BCD and BCO significantly improved the sensorial quality of the samples compared to CO, GTD, and GTO. Based on the results, the application of black cumin extract and oil was effective with at least a 5-day extension of shelf life in preserving the quality of rainbow trout fillets.

Horse mackerel (Trachurus trachurus) fillets biopreservation by using gallic acid and chitosan coatings

Atlantic horse mackerel (Trachurus trachurus) fillets were coated by gallic acid and chitosan solutions, including chitosan nanoparticles, and fish quality and shelf life were assessed during chilled storage for 13 days. All chitosan-containing coatings decreased microorganisms’ growth in more than 2 log cycles up to late storage stages; however, those with chitosan nanoparticles resulted to be more effective, probably due to a greater contact surface with fish muscle. Furthermore, the lowest total volatile basic nitrogen (TVB-N) values, as well as pH values below 7, were found for horse mackerel fillets coated by those solutions with chitosan nanoparticles. Additionally, horse mackerel fillets coated by solutions with chitosan nanoparticles also showed the lowest thiobarbituric acid reactive substances (TBARS) values, maybe owing to a more sustained release of gallic acid. In this regard, it is worth noting that, although gallic acid solution showed no antimicrobial activity, this prevented lipid oxidation and, therefore, preserved color and texture during the chilling storage.