Total Volatile Basic Nitrogen Values Research Articles

Effects of Red Vinasse on Physicochemical Qualities of Blue Round Scad (Decapterus maruadsi) During Storage, and Shelf Life Prediction

A fish processed with red vinasse is a type of Fujian cuisine with regional characteristics. In order to monitor the effect of red vinasse on storage quality and shelf life of blue round scad (Decapterus maruadsi) during storage, the changes in fat content, thiobarbituric acid reactive substances (TBARS), composition of polyunsaturated fatty acids (PUFAs), pH value, texture, and sensory quality were studied at different storage temperatures (4 °C, 25 °C, and 37 °C). By analyzing the correlation between changes in sensory qualities and physical and chemical indexes, a first-order kinetic model and the Arrhenius equation were used to build a shelf-life prediction model for blue round scad during storage. The results showed that processing with red vinasse can significantly reduce the malondialdehyde (MDA) production and the decrease in PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (p < 0.05) during storage. Based on partial least squares regression (PLSR), the storage temperature and time have a significant impact on the PUFA composition in blue round scad, which changed less when the samples were stored at 4 °C and 25 °C, and they had better nutritional composition of fatty acids at lower temperatures. Among the PUFAs, DHA (C22:6n-3) and EPA (C20:5n-3) had higher relative contents and significantly decreased during storage (p < 0.05). Additionally, the processing with red vinasse can slow down the increase in total volatile basic nitrogen (TVB-N) value and pH of blue round scad, maintain the appropriate hardness, elasticity, cohesion and chewability, and improve the overall sensory quality of the fish. In addition, according to the results of model prediction based on TBARS value, the storage shelf life of blue round scad with red vinasse added was 55 d, 2.7 d and 28 h at 4 °C, 25 °C and 37 °C, respectively. The accuracy of the forecast model was high, and the relative errors of the measured values and predicted values were less than 10%. Thus, it not only provided a theoretical basis for the processing and application of red vinasse to Chinese traditional food, but also provided innovative ideas for the safe storage and high-value utilization of blue round scad.

Nondestructive freshness prediction of large yellow croaker (Pseudosciaena crocea) using computer vision and machine learning techniques based on pupil color.

Conventional methods for evaluating of fish freshness based on physiological and biochemical methods are often destructive, complicated, and costly. This study aimed to predict the freshness of large yellow croaker which was sampled every second day in 9 consecutive days at 4°C, using computer vision technology combined with pupil color parameters and different machine learning algorithms (back propagation neural network, BPNN; radial basis function neural network; support vector regression; and random forest regression, RFR). In the process of model building, the RFR model provided the most accurate prediction for the value of total volatile basic nitrogen (TVB-N), with the R-square of the test set ( ) of 0.993. The BPNN model exhibited the best fit for predicting the value of thiobarbituric acid (TBA), with of 0.959. Additionally, the RFR model was the most effective in forecasting total viable count (TVC), with of 0.935. After validation, the root mean square error values of the RFR model for predicting TVB-N value, TBA value, and TVC value were the lowest, which were 0.764, 0.067, and 0.219, respectively. It demonstrated the applicability and good predictive performance of the RFR model for predicting biochemical and microbiological indicators. These findings also demonstrated that monitoring the changes in pupil color could successfully predict the freshness of chilled fish. PRACTICAL APPLICATION: Application Scenario: Quality inspectors detect changes in thefreshness of large yellow croaker in real time from the beginning of distribution to the selling site.

Monitoring Meat Freshness with Intelligent Colorimetric Labels Containing Red Cabbage Anthocyanins Copigmented with Gelatin and Gallic Acid.

Polyvinyl alcohol (PVA)-based pH-responsive color indicators were developed using red cabbage anthocyanin (Anth) copigmented with gelatin and gallic acid (GA). The indicator prepared with gelatin and GA (GA/gelatin/Anth/PVA) was highly resistant to light exposure. GA/gelatin/Anth/PVA exhibited distinct color changes in pH 2-11 buffer solutions and stable color indication in acidic and neutral solid systems (pH 2 and 7) at 97% relative humidity. GA/gelatin/Anth/PVA exhibited the highest sensitivity to dimethylamine, followed by ammonia and trimethylamine. The addition of gelatin and GA facilitated hydrogen bonding, which enhanced thermal stability and water solubility without compromising tensile properties. A color change from purple to blue signaled spoilage when total volatile basic nitrogen values for beef and squid reached 21.0 and 37.8 mg/100 g, respectively. The GA/gelatin/Anth/PVA indicator shows potential for indicating the freshness of raw beef.

Controlling the quality of Patinopecten yessoensis from the perspective of the ultrasound and ferulic acid influences.

In this study, the effects of ultrasound combined with ferulic acid (FA) on the quality of the Yesso scallop (Patinopecten yessoensis) adductor muscles (SAM) during refrigerated storage were investigated. The results demonstrated that the combined treatment with 350W ultrasound and FA (UFA) significantly delayed enzyme activities and microbial growth in SAM tissues compared to FA treatment alone. After 6 days of cold storage, samples treated with UFA exhibited higher hardness (2850g), lower thiobarbituric acid reactive substances (TBARS=9.35 MDA mg/g SAM), and lower total volatile basic nitrogen (TVB-N=19.75mg/100g SAM) values compared to control and FA-treated samples. Consequently, UFA treatment prolonged the shelf life of SAM by 3 days during storage at 4°C. Based on scanning electron microscopy and low-field nuclear magnetic resonance data, these findings are attributed to UFA treatment not only reducing the degradation of SAM tissue network structure but also minimizing water loss. PRACTICAL APPLICATION: Scallop adductor muscle (SAM) is commonly considered a delicacy owing to its unique mouthfeel and delicious taste. However, owing to its high moisture content and high levels of various nutrients, SAM has a short shelf life. In this work, a combination of ultrasound with ferulic acid (UFA) has been found to have effective preservation effects on SAM during refrigerated storage. Our study findings pave the way for a potential approach to maintain scallop quality during processing and storage. Moreover, our study also provides some theoretical basis for using and promoting these technologies in aquatic products.

A novel fluorescence platform for portable and visual monitoring of meat freshness

Biogenic amines (BAs) are crucial markers of meat spoilage. Developing practical and effective BAs detection methods is essential for monitoring meat freshness and ensuring daily consumption safety. This study prepared several naphthalene-based fluorescent compounds to visually monitor meat freshness in real-time. These probes show a colorimetric fluorescence response to putrescine and cadaverine (typical spoilage indicators) through nucleophilic addition/elimination reaction. The detectability of these probes can be optimized by altering the electronegativity and substitution position of the recognition group. Among these compounds, 2-((6-(4-(diphenylamino)phenyl)naphthalen-2-yl)methylene)malono nitrile (TNMA) demonstrated exceptional sensing performance toward putrescine and cadaverine, including high-contrast fluorescence color transition (red to blue), rapid response times (∼30 s), high selectivity and sensitivity (detection limit for putrescine: 2.69 ppm, cadaverine: 6.11 ppm). Furthermore, the B/R values of TNMA test strips output by RGB analysis presented a linear correlation with total volatile basic nitrogen (TVBN, an international standard for evaluating food spoilage) values in pork. Based on this correlation, we utilized smartphone applications to construct an intelligent evaluation system, enabling visual monitoring of pork, chicken, and shrimp freshness under various storage conditions. The TNMA-based system offers a reliable platform for real-time, portable and visual monitoring of meat freshness for consumers and suppliers in the food industry.

Microbial composition of spoiled irradiated ready-to-eat chicken feet and their spoilage characteristics

The spoilage of irradiated ready-to-eat chicken feet (RTECF) seriously affects the food's quality, resulting in package swelling and off-flavors, both of which are highly undesirable to stakeholders and consumers. To investigate the spoilage characteristics of irradiated RTECF and the microorganisms responsible for the spoilage and swelling, the changes in physicochemical properties, microbial community, and volatile organic compounds (VOCs) between normal and spoiled RTECF were evaluated. Compared with normal samples, the spoiled RTECF showed a higher pH value and total volatile basic nitrogen (TVB-N) value, lower color value, and texture features (P < 0.05). Acinetobacter, Pseudomonas, Lactobacillus, and Candida were the dominant genera responsible for RTECF spoilage as confirmed through both culture-dependent methods and high-throughput sequencing (HTS). The results of the verification for gas-producing strains showed that Lactobacillus brevis could cause RTECF packaging to swell. A total of 20 key VOCs were identified using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results of Pearson correlation analysis (|r|>0.8, P < 0.05) showed that 12 dominant core microbial genera had a significant effect on the flavor of RTECF before and after spoilage. This study provides a theoretical reference for solving the problem of RTECF spoilage and improving the overall quality of RTECF products.

A Self‐Calibrating Sensing Platform Based on Amine‐Responsive Excitation Wavelength‐Dependent Fluorescent Polymers for Real‐Time and Visual Detection of Food Freshness

AbstractAccurate assessment of food freshness is critical to maintaining human health. However, the complex environment of food usually leads to false‐positive measurements result. Therefore, the development of sensing platforms with self‐calibration for accurate detection of food freshness in complex environments is essential. Here, using the green fluorescence‐emitting FITC‐ene and the red fluorescence‐emitting DBA‐ene‐Eu3+ as fluorescent units, fluorescent polymeric materials P1‐P4 with excitation wavelength‐dependent (254 and 365 nm, matched with standard UV lamp) emission are prepared. P1‐P4 responded rapidly to biogenic amines (BAs). Among them, P3 exhibits the widest linear range, and the most noticeable fluorescence color change (from orange‐red to yellow‐green) under 254 nm excitation and enhanced green fluorescence under 365 nm excitation. The changes of P3‐prepared labels at different excitation wavelengths can be utilized to rapidly evaluate the food's freshness. Furthermore, by using a smartphone to read the Red/Green/Blue values of the labels, the total volatile basic nitrogen (TVBN) values can be output to quantitatively evaluate the food freshness, and the output TVBN values at different excitation wavelengths are utilized for mutual calibration to improve the accuracy of the estimation results. This self‐calibrating sensing platform is fast and nondestructive, which provides an effective method for the accurate evaluation of food freshness.

Designing the pH-sensitive indicator based on starch nanoparticle with bromocresol green for monitoring meat spoilage

ABSTRACT The starch nanoparticle, combined with bromocresol green (BCG), served as a pH-sensitive indicator to monitor meat quality throughout an 8-day refrigerated storage period. The meat samples were sealed in package which the pH-sensitive indicator attached to the interior part of packaging lid. The changes in meat quality were evaluated by total volatile base nitrogen (TVBN), pH, total viable count (TVC), sensory analysis, and color in interval of 0, 3, 5, 7, and 8-days storage at 4°C. Initial TVBN values were recorded at 19.6 mg/100 g, increased to 26.6 mg/100 g by the end of storage period. The pH value was significantly increased after 8 days storage at 4°C. The observed color variation in the indicator from yellow to blue was attributed to the concurrent increases in TVBN, TVC, and pH. The indicator color changes had significant correlation with analyzed chemical quality of stored meat. Therefore, the designed BCG pH-sensitive indicator could be effective in monitoring the meat spoilage during storage.

The enhancement mechanism of adding stachyose to Lactiplantibacillus plantarum SS-128 in the probiotic/prebiotic combination biopreservation in salmon

Lactiplantibacillus plantarum SS-128 (SS-128) is a biocontrol bacterium used to preserve food freshness. However, its performance with aquatic products is limited due to unstable adhesion. This study investigated how stachyose affects SS-128's growth, acid production, and biofilm formation, and explored the preservation mechanism of the probiotic/prebiotic combination as a biocontrol agent. Stachyose shortened the lag phase of SS-128 growth and gave it a competitive advantage over other microorganisms. It greatly enhanced SS-128's acid production, lowering the environmental pH and inhibiting spoilage bacteria growth. Additionally, stachyose increased SS-128's biofilm production by 74% and increased its adhesion to the surface of aquatic products. Using this probiotic/prebiotic combination, the shelf life of salmon was extended from 4 to 8 days. On the 8th day of storage, the TVB-N (Total Volatile Basic Nitrogen) values of the LAB/Stachyose group remained within the acceptable range at 0.28 g N/kg. This demonstrates that stachyose significantly contributes to SS-128's biopreservation effect. Thus, this probiotic/prebiotic combination had great potential for application in other aquatic products and the broader food industry.

Quality non-destructive sorting of large yellow croaker based on image recognition

The YOLOv7 algorithm was used to establish a fast and non-destructive quality identification model for large yellow croaker (Larimichthys crocea) in this study. The cross multi-head attention mechanism in the swin transformer was incorporated into the neck of YOLOv7 architecture to enhance the recognition performance. The freshness classification model based on the total volatile basic nitrogen value was evaluated by freshness indicators, visual features, and texture profile analysis (TPA). The findings indicated that the enhanced model achieved an accuracy rate of 98.6% in freshness classification, which was higher than 85.6% of the original model. Visual features (fish-eye plumpness and turbidity) were highly correlated with all freshness indexes (all above 0.8). The accuracy of freshness discrimination in different lighting environments was also greater than 90%. These results collectively indicate the potential for the eye region images to serve as a reliable indicator for the sorting of freshness in large yellow croakers.

Impact of Packaging Methods Coupled with High Barrier Packaging Loaded with TiO2 on the Preservation of Chilled Pork.

This study investigated the impact of packaging methods coupled with high barrier packaging loaded with titanium dioxide (TiO2) on the quality of chilled pork. The experiment consisted of three treatment groups: air packaging (AP), vacuum packaging (VP), and vacuum antibacterial packaging (VAP). Changes in total viable count (TVC), pH value, total volatile basic nitrogen (TVB-N) value, sensory attributes, and water holding capacity of pork were analyzed at 0, 3, 6, 9, and 12 d. TVC of the VAP group was 5.85 Log CFU/g at 12 d, which was lower than that of AP (6.95 Log CFU/g) and VP (5.93 Log CFU/g). The antibacterial film incorporating TiO2 effectively inhibited microorganism growth. The VAP group exhibited the lowest pH value and TVB-N value among all the treatment groups at this time. The findings demonstrated that the application of VAP effectively preserved the sensory attributes of pork, the hardness, cohesiveness and adhesiveness of pork in VAP group were significantly superior than those in AP group (p<0.05), but not significantly compared with VP group. On the 12 d, the CIE a* value of pork in VAP group was significantly higher (p<0.05). This exhibited that VAP could effectively maintain the freshness of chilled pork and extend the shelf life for 3 d compared to the AP group. These findings provide empirical evidence to support the practical implementation of TiO2-loaded packaging film in the food industry.

Evaluation of fish meal freshness using a metal-oxide semiconductor electronic nose combined with the long short-term memory feature extraction method.

To improve the classification and regression performance of the total volatile basic nitrogen (TVB-N) and acid value (AV) of different freshness fish meal samples detected by a metal-oxide semiconductor electronic nose (MOS e-nose), 402 original features, 62 manually extracted features, manually extracted and selected features by the RFRFE method, and the features extracted by the long short-term memory (LSTM) network were used as inputs to identify the freshness. The classification performance of the freshness grades and the estimation performance of the TVB-N and AV values of fish meal with different freshness were compared. According to the sensor response curve, preprocessing and feature extraction steps were first applied to the original data. Then, five classification algorithms and four regression algorithms were used for modeling. The results showed that a total of 30 features were extracted using the LSTM network, and the number of extracted features was significantly reduced. In the classification, the highest accuracy rate of 95.4% was obtained using the support vector machine method. In the regression, the least squares support vector regression method obtained the best root mean square error (RMSE). The coefficient of determination (R2), RMSE, and relative standard deviation (RSD) between the predicted value of TVBN and the actual value were 0.963, 11.01, and 7.9%, respectively. The R2, RMSE, and RSD between the predicted value of AV and the actual value were 0.972, 0.170, and 6.05%, respectively. The LSTM feature extraction method provided a new method and reference for feature extraction using an E-nose to identify other animal-derived material samples.

Potential of two-dimensional correlation-based dual-band visible/near infrared spectroscopy to predict total volatile basic nitrogen content in meat

In the meat industry, it is essential to monitor the total volatile basic nitrogen (TVB-N) content due to its impact on human diets safety. In the present study, two-dimensional correlation spectroscopy (2D-COS) was combined with dual-band visible/near-infrared spectroscopy to identify the characteristic wavelengths of TVB-N in pork meat during storage. Reflectance spectra of pork longissimus dorsi muscles at 350–1100 nm and 1000–2500 nm were obtained during a 13-day storage period. The dual-band spectra were merged via parabolic fitting, and subjected to pre-treatments using absorbance conversion, first derivation (FD), and standard normal variate transformation (SNV). Then, the storage day was used as the external perturbation factor, and 2D-COS was performed on the dynamic spectra to identify TVB-N-related wavebands. Twenty-five characteristic wavelengths were selected, and a simplified partial least square regression (PLSR) model was established with a correlation coefficient (Rp) of 0.9591, root mean square error on prediction (RMSEP) of 1.8341 mg/100 g, and relative percent deviation (RPD) of 3.2518. These results outperformed those of the model based on full wavebands data (Rp = 0.9215, RMSEP = 2.8191 mg/100 g, RPD = 2.1114). This study accurately predicted TVB-N values in pork meat, and the integration of 2D-COS and dual-band spectra had great potential for real-time meat freshness evaluation.

Prediction of total volatile basic nitrogen (TVB-N) in fish meal using a metal-oxide semiconductor electronic nose based on the VMD-SSA-LSTM algorithm.

The total volatile basic nitrogen (TVB-N) is the main indicator for evaluating the freshness of fish meal, and accurate detection and monitoring of TVB-N is of great significance for the health of animals and humans. Here, to realize fast and accurate identification of TVB-N, in this article, a self-developed electronic nose (e-nose) was used, and the mapping relationship between the gas sensor response characteristic information and TVB-N value was established to complete the freshness detection. The TVB-N variation curve was decomposed into seven subsequences with different frequency scales by means of variational mode decomposition (VMD). Each subsequence was modelled using different long short-term memory (LSTM) models, and finally, the final TVB-N prediction result was obtained by adding the prediction results based on different frequency components. To improve the performance of the LSTM, the sparrow search algorithm (SSA) was used to optimize the number of hidden units, learning rate and regularization coefficient of LSTM. The prediction results indicated that the high accuracy was obtained by the VMD-LSTM model optimized by SSA in predicting TVB-N. The coefficient of determination (R2), the root-mean-squared error (RMSE) and relative standard deviation (RSD) between the predicted value and the actual value of TVBN were 0.91, 0.115 and 6.39%. This method improves the performance of e-nose in detecting the freshness of fish meal and provides a reference for the quality detection of e-nose in other materials. © 2024 Society of Chemical Industry.

Development of active hydrogel absorbent pads based on sodium alginate/potassium-doped carbon dots for chilled pork preservation

In this study, potassium-doped carbon dots (K-CDs) were added to sodium alginate (NaAlg) hydrogel to yield high-strength, antibacterial, antioxidant NaAlg hydrogel absorbent pads (NaAlg/K-CDs) to absorb chilled pork exudate during storage. The results revealed that the swelling rates of the NaAlg/K-CDs peaked at 3286.83%, a figure exceeding that of the commercial absorbent pads. Based on the bacterial diversity and richness results, Pseudomonas aeruginosa (P. aeruginosa) was evidently the dominant spoilage organism during chilled pork storage. On storage day 6, the P. aeruginosa population in the NaAlg/K-CDs hydrogel absorbent pad group was 82% of that in the control group. The total volatile basic nitrogen (TVB-N) value of the NaAlg/K-CDs group remained lower than 0.15 mg/g on day 8. The pH, TVB-N, total viable count (TVC), cooking loss, and volatile odour values of the chilled pork in the NaAlg/K-CDs hydrogel absorbent pad group were significantly lower than those in other absorbent pad groups. Moreover, the colour change and shear force values of the chilled pork in the NaAlg/K-CDs hydrogel absorbent pad group were lower than those in the control and wood fiber paper absorbent pad groups. These results indicate that the shelf life of the NaAlg/K-CDs-packaged chilled pork was extended by 2 days compared with that of the control. Therefore, the NaAlg/K-CDs hydrogel absorbent pads potentially inhibited microbial growth and improved the storage quality of chilled pork. This study provides an alternative solution against traditional chilled pork absorbent pads, further promoting the advancement of fresh meat preservation techniques.

Application of Ulva lactuca polysaccharide in the preservation of refrigerated of Lateolabrax maculatus fillets

This study aimed to explore the use of Ulva lactuca polysaccharide (ULP) as a preservative for perch (Lateolabrax maculatus) fillets stored under refrigeration at 4 °C. Fresh perch fillets were treated with ULP (7–10 kDa) and potassium sorbate, respectively, to evaluate their effectiveness in inhibiting bacterial growth and maintain freshness. A 0.5% ULP solution significantly decreased the pH value, total volatile basic nitrogen value, thiobarbituric acid value, and total bacterial count of perch fillets. ULP solution delayed the changes in whiteness and texture of fillets, as well as protein degradation. The acute toxicity experiment further evaluates the safety and reliability of ULP. Simultaneously, utilizing 16S rRNA techniques, the ULP solution inhibited microorganisms known for their strong spoilage capabilities, such as Pseudomonas, Actinetobacter, and Shewanella. Microorganisms with a weaker ability to cause corruption became the dominant bacteria, such as Acetobacter, Lactobacillus, and Faecalibacterium, thereby exerting a degree of inhibition against spoilage.

Identification of the anthocyanin profile from butterfly pea (Clitoria ternatea L.) flowers under varying extraction conditions: Evaluating its potential as a natural blue food colorant and its application as a colorimetric indicator

This study aims to extract anthocyanins from BPF (Butterfly Pea Flower) to determine an effective solvent combination resulting in higher total anthocyanin content. Various solvent combinations were utilized to discern crucial characteristics of the obtained BPFE (Butterfly Pea Flower Extract). The BPFE from the optimal treatment was utilized as a pigment in colorimetric indicators, which were then evaluated for their initial response to seafood spoilage stored at room temperature for 24 h. The color change response of the colorimetric indicators employing BPFE pigment was compared with the pH and TVBN (Total Volatile base Nitrogen) values of the seafood initially and after 24 h. The highest total anthocyanin content was achieved with the combination of 96 % ethanol/1.5 N HCl (85:15, v/v) at 551.06 mg/L, followed by the combination of 96 % ethanol/distilled water (70:30, v/v) with pH adjustment to 1 using 1.5 N HCl at 484.27 mg/L. Subsequent combinations, in decreasing order, were 96 % ethanol/1.5 N HCl (99:1, v/v), 96 % ethanol/distilled water (70:30, v/v), and lastly, 96 % ethanol/distilled water (30:70, v/v), with total anthocyanin content of 275.53 mg/L, 200.39 mg/L, and 125.24 mg/L, respectively. BPFE applied in colorimetric indicators demonstrated responsiveness to seafood spoilage through color changes, with tested spoilage indicators being pH and TVBN. The initial (first hour) pH and TVBN values for each tested seafood were 5.5 and 9.42 mg/100 g (Scylla serrata), 6.4 and 4.23 mg/100 g (Litopenaeus vannamei), 5.4 and 11.29 mg/100 g (Uroteuthis sibogae), and 6.5 and 10.26 mg/100 g (Restrelliger kanagurta). Meanwhile, the pH and TVBN values after 24-h storage at room temperature became 7.9 and 57.01 mg/100 g, 7.4 and 76.65 mg/100 g, 7.5 and 216.44 mg/100 g, and 7.8 and 51.86 mg/100 g, respectively. The conclusion drawn is that the extraction of BPFE is more efficient when utilizing acidified ethanol solvent, and the resulting BPFE holds promise as a reliable pH indicator.

Combined Effect of an Active AgIon® Absorbent Pad and a Chitosan Coating on the Preservation of Fresh Beef.

In the present study, the combined effect of an AgIon® antimicrobial absorbent (Ζ) pad and a chitosan coating (C) on the preservation of fresh beef stored aerobically at 5 °C was investigated. Microbiological, physicochemical, and sensory attributes were monitored for up to 10 days of storage. The microbiological data indicated that the C and chitosan coating plus absorbent pad (CZ) treatments were the most efficient in reducing total viable counts (TVC) by 4.09 and 3.53 log cfu/g compared to the control W and Z treatments on day 4 of storage (p < 0.05). An analogous reduction in the counts of the other microbial groups monitored was recorded. pH values were ca. 5.7 for treatments W and Z and 5.45 for treatments C and CZ on day 4 of storage (p < 0.05). The total volatile basic nitrogen (TVB-N) values remained <20 mg/100 g for all treatments on day 4 and for treatments C and CZ on day 10 of storage. The total color difference values decreased (p < 0.05) during storage for treatments W and Z, but remained constant for treatments C and CZ. Based on sensory, microbiological and physico-chemical data, beef shelf life was ca ^# + 3 days for samples W and Z and at least 10 + 3 days for samples C and CZ. Between the two antimicrobial treatments, chitosan was considerably more effective than the AgIon® antimicrobial absorbent pad, which showed practically no antimicrobial activity in direct contact with beef meat.

Growth Reduction of Vibrionaceae and Microflora Diversity in Ice-Stored Pacific White Shrimp (Penaeus vannamei) Treated with a Low-Frequency Electric Field.

A novel storage technique that combines the low-frequency electric field (LFEF) and ice temperature was used to extend the shelf life of Pacific white shrimp (Penaeus vannamei). The study investigated the effect of LFEF treatment on the quality and microbial composition of Penaeus vannamei during storage at ice temperature. The results showed that the LFEF treatment significantly extended the shelf life of shrimp during storage at ice temperature. The total volatile base nitrogen (TVB-N) and pH of samples increased over time, while the total viable count (TVC) showed a trend of first decreasing and then increasing. Obviously, shrimp samples treated with LFEF had a lower pH, TVB-N and TVC values than the untreated samples (p < 0.05) at the middle and late stages of storage. LFEF treatment increased the diversity and altered the composition of the microbial communities in Penaeus vannamei. Additionally, the treatment led to a decrease in the relative abundance of dominant spoilage bacteria, including Aliivibrio, Photobacterium and Moritella, in Penaeus vannamei stored at ice temperature for 11 days. Furthermore, correlation analysis indicated that TVB-N and pH had a significant and positive correlation with Pseudoalteromonas, suggesting that Pseudoalteromonas had a greater impact on shrimp quality. This study supports the practical application of accelerated low-frequency electric field-assisted shrimp preservation as an effective means of maintaining shrimp meat quality.

The effect of carvacrol, thymol, eugenol and α-terpineol in combination with vacuum packaging on quality indicators of anchovy fillets

Food safety issues associated with the increased use of synthetic and chemicals preservatives agents are receiving increasing attention. The utilisation of natural resources may provide a potential and advisable alternative to chemical preservatives in the seafood industry. This research study focused on the impacts of pure bioactive compounds (carvacrol, thymol, eugenol, and α-terpineol) on the sensory and microbiological (total viable count, TVC) and chemical qualities (total volatile basic nitrogen (TVB-N) value, thiobarbituric acid (TBA), free fatty acid (FFA), and peroxide value (PV)) of vacuumed packaged anchovy (Engraulis encrasicolus) fillets during the refrigerated storage period. This study also evaluated the potential effect of bioactive compounds on biogenic amines (BAs) and ammonia (AMN) production in fish samples. Sensory investigations revealed that the control had an 8-day shelf life, that of the carvacrol and α-terpineol treatment was 15 days, and that of the thymol and eugenol treatment was 19 days. The application of bioactive compound on fish had a positive impact on the preservation of its oxidative stability through the reduction of TBA, FFA, and PV values as well as enhancement of the microbiological quality in comparision to the control. The use of pure bioactive compounds resulted in the reduction of the accumulation of BAs and AMN in anchovy fillets during 22 days of storage. The results exhibited that the pure bioactive compounds mainly eugenol and thymol, can increase the shelf life of anchovy. Therefore, they can be used by seafood industries as preservative agents due to their good antimicrobial and antioxidant activities.