Determination Of Fish Freshness Research Articles

Amine vapor-responsive ratiometric sensing tag based on HPTS/TPB-PVA fluorescent film for visual determination of fish freshness

In this study, amine vapor-sensitive films with ratiometric fluorescence attributes were developed. The pH-sensitive fluorescein 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) and its tetraphenylethylene derivative (TPB) were selected as ratiometric indicators and incorporated into a polyvinyl alcohol (PVA) matrix to produce HPTS/TPB-PVA films. The films responded well to amine vapors, and the interference of aromatic vapors did not substantially affect the fluorescence signals of the films. Under UV light at a wavelength of 365 nm, the fluorescence of the films changed from dark pink to light pink and finally to yellow when the freshness of the fish was visually checked during storage. In addition, the color difference values of the films showed a positive correlation with the total volatile basic nitrogen (TVB-N), ranging from 12.7 to 24.8 mg/100 g at 25 °C and 8.4 to 25.6 mg/100 g at 4 °C, respectively. This indicates that fluorescent films have good potential for quantifying fish freshness in the near future when connected to an automatic data processing system based on color differences.

Current applications and future trends of artificial senses in fish freshness determination: A review.

Fish is a highly demanding food product and the determination of fish freshness is crucial as it is a fundamental factor in fish quality. Therefore, the fishery industry has been working on developing rapid fish freshness determination methods to monitor freshness levels. Artificial senses that mimic human senses are developed as convenient emerging technologies for fish freshness determination. Computer vision, electronic nose (e-nose), and electronic tongue (e-tongue) are the emerging artificial senses for fish freshness determination. This review article is uniquely worked upon to investigate the current applications of the artificial senses in fish freshness determination while describing the steps, and fundamental principles behind each artificial sense, comparing them with their advantages and limitations, and future trends related to fish freshness determination. Among the artificial senses, computer vision determines the freshness of fish in a completely nondestructive way while the e-tongue determines the freshness of fish in a completely destructive way. There are developed e-noses for fish freshness determination in both destructive and nondestructive ways. By analyzing visual cues such as color, computer vision systems can assess fish quality without the need for physical contact and it makes computer vision suitable for large-scale industrial fish quality assessing applications. Overall, this review study reveals artificial senses as a proven replacement for traditional sensory panels in determining fish freshness precisely and conveniently. As future trends, there is a demand for developing applications for consumers to determine fish freshness based on artificial senses.

Use of colorimetric data and artificial neural networks for the determination of freshness in fish

The determination of fish freshness is conducted by different methods, of which, in general, reagents with a high degree of toxicity or dangerousness are used, besides requiring the use of large volumes of drinking water and electricity. Thus, the objective was to develop an alternative analytical method, fast, easy to perform and environmentally friendly for the determination of freshness in fish, based on Total Volatile Basic Nitrogen (TVB-N) and CIELab and RGB colorimetric data associated with chemometrics and the Artificial Neural Networks (ANN) technique. Through the evaluation of the figures of merit, it was possible to verify promising results for the use of the developed alternative in future predictions of freshness in fish, demonstrating its suitability for a more robust quality control. In view of the above, the modeling of colorimetric data by ANN models is in line with the requirements of the 4.0 food industry, since it is a fast method and because it is a sustainable alternative not only environmentally, but also economically, since it encourages the application of green and low-cost tools.

Fabrication of an Immobilized Polyelectrolite Complex (PEC) Membrane from Pectin-Chitosan and Chromoionophore ETH 5294 for pH-Based Fish Freshness Monitoring

Considering the significance of its demand around the world, the accurate determination of fish freshness with a simple and rapid procedure has become an interesting issue for the fishing industry. Hence, we aimed to fabricate a new optical pH sensor based on a polyelectrolyte (PEC) membrane of pectin–chitosan and the active material chromoionophore ETH 5294. A trial-and-error investigation of the polymer compositions revealed that the optimum ratio of pectin to chitosan was 3:7. With an optimum wavelength region (λ) at 610 nm, the constructed sensor was capable of stable responses after 5 min exposure to phosphate-buffered solution. Furthermore, the obtained sensor achieved optimum sensitivity when the PBS concentration was 0.1 M, while the relative standard deviation values ranged from 2.07 to 2.34%, suggesting good reproducibility. Further investigation revealed that the sensor experienced decreased absorbance of 16.67–18.68% after 25 days of storage. Employing the optimum conditions stated previously, the sensor was tested to monitor fish freshness in samples that were stored at 4 °C and ambient temperature. The results suggested that the newly fabricated optical sensor could measure pH changes on fish skin after 25 h storage at room temperature (pH 6.37, 8.91 and 11.02, respectively) and 4 °C (pH 6.8, 7.31 and 7.92, respectively).

One-Step and Colorimetric Detection of Fish Freshness Indicator Hypoxanthine Based on the Peroxidase Activity of Xanthine Oxidase Grade I Ammonium Sulfate Suspension.

The global food waste problem, especially aquatic product spoilage, stimulates the accurate freshness analysis of food products. However, it still remains a great challenge to realize in-field determination of fish freshness at the time of use. In the present study, a colorimetric enzyme biosensor was developed for one-step detection of hypoxanthine (Hx), which is an important intermediate of adenosine triphosphate decomposition during fish storage. We demonstrate that xanthine oxidase grade I ammonium sulfate suspension (XOD-ASS) possesses peroxidase activity. It can oxidize different peroxidase substrates, including 3,3′,5,5′-tetramethylbenzidine, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, and o-phenylenediamine in the presence of H2O2, producing visible color reactions. Further experiments indicate that XOD-ASS displayed effective peroxidase activity and could be used for H2O2 detection. Based on this, a one-step Hx detection method was established using only XOD-ASS as the catalyst. The method displays a good linear relationship in the range from 20 to 100 μM with a detection limit of 6.93 μM. Additionally, we successfully applied this method in testing Hx accumulation in sea bass fish samples of different storage times. The recovery values range from 97.44 to 102.56%. It is exciting to note that, compared with other methods, our proposed method provides a robust advantage on the economic reaction system, ease of preparation, short time consumption, and moderate reaction temperature. We believe that this method shows good application prospects for on-site fish freshness determination.

Nutritional profile of nigiri sushi meal and the usage of citrate synthase activity as freshness parameter

The aim of the study was to access the influence of nigiri sushi meal ingredients ratio on its weight, nutritional profile, physic-chemical characteristics (crude protein, lipid content, ash content, salt content, phosphorus content and thiobarbituric acid assay) and to estimate the usage of citrate synthase activity as freshness index of seafood used for sushi preparation. Nutrition composition of nigiri sushi is highly influence by rice/seafood ratio. Inclusion of processed seafood in sushi can influence significantly weight and consequently nutritional profile of nigiri sushi meal as well. Shrimp cooking resulted in 16.45±3.29% weight loss in whole non-deveined shrimp and 13.03±3.40% in non-deveined shrimp tail. Nigiri sushi meal prepared with salmon and tuna fish can be recognized as good sources of seafood. Nigiri sushi meal can be considered as a low-calorie meal (nigiri salmon: 716.13±24.18 kJ/100g; nigiri tuna: 638.12±10.64 kJ/100g; nigiri shrimp: 672.06 ± 8.72 kJ/100g) but on the contrary it cannot be considered as low salt content meal (nigiri salmon: 0.97±0.04%; nigiri tuna: 0.89±0.10%; nigiri shrimp: 1.06±0.13%). Citrate synthase activity (CSA) increases after each freezing/thawing cycle and at the end (4th cycle) were 5.29±0.67 μmol/mL/min and 6.67±0.63 μmol/mL/min in tuna and salmon samples, respectively. CSA can be recognized as reliable enzymatic kit indicator for fish freshness determination in nigiri sushi meal.

Freshness assessment of European hake (Merluccius merluccius) through the evaluation of eye chromatic and morphological characteristics

The most commonly used method for fish freshness determination is the sensory inspection; alternative sensory methods such as the Quality Index Method (QIM), based on the significant sensory parameters of one specific species, have been recently suggested. Considering that most of the sensory parameters are based on chromatic and morphological visual impression, the set-up of an objective method using computer vision techniques is very promising. The objective of this research was to characterize the changes in eye chromatic and morphological characteristics of European hake (Merluccius merluccius) during 13 days of storage on ice, using a tailored computer vision technique and a 3D scanner. Results obtained by multivariate statistical analysis of the colour spectra of eye images and by the eye concavity index using a 3D scanner permitted to estimate fish unacceptability after 7 days of storage, in agreement with results obtained by QIM sensory analysis. Moreover, 1H NMR was used to evaluate the production of trimethylamine (TMA) and the Ki index, confirming a good correlation with eye chromatic and morphological features. This preliminary study showed the high potentiality of the developed method as a non-destructive technique for raw fish freshness characterization / prediction, being a promising approach to create a robust portable instrument for the evaluation of fish freshness in real transport and marketing conditions.

Amperometric xanthine biosensors using glassy carbon electrodes modified with electrografted porous silica nanomaterials loaded with xanthine oxidase

Glassy carbon electrodes were modified with silica materials such as silica nanoparticles, mesoporous silica nanoparticles and mesoporous silica thin films with the aim to introduce scaffolds suitable for the immobilization of enzymes. Xanthine oxidase was selected as a model enzyme, and xanthine as the target analyte. A comparison of the modified electrodes showed the biosensor prepared with mesoporous silica nanoparticles to perform best. By using the respective biosensor, xanthine can be amperometrically determined (via measurement of enzymatically formed hydrogen peroxide) at a working voltage of 0.7 V (vs. Ag/AgCl) with a 0.28 μM detection limit. The biosensor was evaluated in terms of potential interferences, reproducibility and stability, and applied to the determination of fish freshness via sensing of xanthine.

A nondestructive method for fish freshness determination with electronic tongue combined with linear and non-linear multivariate algorithms

Electronic tongue coupled with linear and non-linear multivariate algorithms was attempted to address the drawbacks of fish freshness detection. Parabramis pekinensis fish samples stored at 4°C were used. Total volatile basic nitrogen (TVB-N) and total viable count (TVC) of the samples were measured. Fisher liner discriminant analysis (Fisher LDA) and support vector machine (SVM) were applied comparatively to classify the samples stored at different days. The results revealed that SVM model was better than Fisher LDA model with a higher identification rate of 97.22% in the prediction set. Partial least square (PLS) and support vector regression (SVR) were applied comparatively to predict the TVB-N and TVC values. The quantitative models were evaluated by the root mean square error of prediction (RMSEP) and the correlation coefficient in the prediction set (R<sub>pre</sub>). The results revealed that SVR model was superior to PLS model with RMSEP = 5.65 mg/100 g, R<sub>pre</sub> = 0.9491 for TVB-N prediction and RMSEP = 0.73 log CFU/g, R<sub>pre</sub> = 0.904 for TVC prediction. This study demonstrated that the electronic tongue together with SVM and SVR has a great potential for a convenient and nondestructive detection of fish freshness.  

Fish Freshness Monitoring Using an E-Tongue Based on Polypyrrole Modified Screen-Printed Electrodes

In this paper, a novel e-tongue for evaluating biogenic amine compounds is reported. The method uses an array of voltammetric electrodes chemically modified based on screen-printed electrodes. The electrochemical signals toward amines consist in complex voltammetric curves. Cyclic voltammograms show redox processes related to the electrochemical activity of the amine under study, and redox peaks associated with the electrochemical activity of the electroactive material. Additionally, the electroactivity and basic character of amines influences considerably the electrochemical behavior of the electrodic material. The viability of the method is tested for the fish freshness monitoring. The samples are Pontic shad (Alosa Pontica), a fish living in the northwestern part of the Black Sea. Pontic shad migrates in the Danube River for spawning. The pattern of responses provided by the array can be used to discriminate and evaluate the fish freshness state. Principal component analysis confirmed the capability of the sensors array to fish freshness monitoring. Partial least squares-discriminant analysis showed that this method could be used for the analysis and determination of fish freshness as well as determination the postmortem time elapsed.

Droplet-based microfluidic sensing system for rapid fish freshness determination

A microfluidic device was constructed for on-site determination of fish freshness by using adenosine-5′-triphosphate (ATP) concentration as an indicator of freshness. In the device, extracts from fish and reagent solutions were processed in the form of droplets separated by air. The volumes of the droplets of the extract solution, a solution containing enzyme substrates, and a washing buffer solution were measured in branched flow channels. To simplify the structure and procedure for mixing solutions, a wider portion was formed in one flow channel to merge the droplets. A row of droplets was ejected from each of three branched flow channels, merged in the wider portion, and transported to a sensing region located downstream. ATP was detected using two enzymatic reactions involving glycerol kinase (GK) and glycerol-3-phosphate oxidase (G3PO). A linear relationship between the generated current and ATP concentration was confirmed, and ATP detection from jack mackerel extracts was carried out. A distinct change in the current was observed with the fresh extracts as in the case of standard solutions. The obtained data correlated well with those obtained by high-performance liquid chromatography (HPLC).

Improvement of Fish Freshness Determination Method by the Application of Amorphous Freeze-Dried Enzymes

Alkaline phosphatase (ALP), nucleoside phosphorylase (NP), and xanthine oxidase (XOD) were used in a colorimetric method for evaluation of fish freshness based on the Ki value. Two enzyme mixtures, NP-XOD and ALP-NP-XOD, were prepared with a color developing agent, and stabilities of the enzymes were improved by freeze-drying with glass-forming additives, i.e., sucrose and sucrose-gelatin. As a result, a linear relationship was obtained between the Ki values determined by the developed colorimetric method and a conventional high-performance liquid chromatography with a high correlation coefficient of 0.997. All enzyme samples containing the additive(s) were amorphous, and higher enzymes activities were maintained compared to those freeze-dried without an additive. Sucrose-gelatin/enzyme mixtures showed higher glass transition temperature; consequently, the enzymes were better stabilized than the sucrose/enzyme formulations. Using the sucrose-gelatin/enzyme mixture, Ki values of fish meat could be accurately determined even after 6-month storage of the dried enzymes at 40 °C.

Comparison of polypyrrole-based xanthine oxidase amperometric and potentiometric biosensors for hypoxanthine

Abstract The preparation and performance of xanthine oxidase electrochemical biosensor developed for the determination of hypoxanthine is reported. Xanthine oxidase (XOD) and a mediator potassium ferrocyanide (K 4 Fe(CN) were entrapped into a polypyrrole (PPy) film during galvanostatic film formation. The optimum conditions for the formation of PPy-XOD-Fe(CN) 6 4− film include 0.4 M pyrrole, 6.2 U/mL XOD, 40 mM K 4 Fe(CN) 6 , polymerisation period of 200 s, and an applied current density of 0.5 mA/cm 2 . Two modes of detection, the potentiometric and amperometric modes, were investigated. The optimum potential for the amperometric biosensing of hypoxanthine was 800 mV vs. Ag/AgCl (3 M KCl) in 0.05 M phosphate buffer. A comparison of the sensitivities for the amperometric and potentiometric modes revealed that potentiometric detection was more sensitive and amperometric detection gave a wider linear concentration range. The PPy-XOD biosensor was successfully used for the determination of fish freshness.

An electronic tongue for fish freshness analysis using a thick-film array of electrodes

We report on the development of an electronic tongue as potential tool for fish freshness determination. The studies were carried out following the evolution with time on fillet of cultured sea bream (Sparus Auratus). The electronic tongue consists of 16 potentiometric electrodes of the type metal, metal oxide and insoluble metal salts. Graphite was also used as electrode. Fish freshness indicators such as texture, pH, colour, microbial analysis, total volatile basic nitrogen (TVB-N) and biogenic amines were also determined versus time. The effectivity of the electronic tongue in the assessment of the evolution with time of fish fillets was evaluated. First the electronic tongue was used to classify samples according to time. Perceptron and adaptive resonance theory were used to discriminate between the data from different days. In a second step, the electronic tongue was used to predict the results obtained from chemical and biochemical analyses by building quantitative partial least square (PLS) models. A remarkable correlation was found between the electronic tongue formed by the 16 simple electrodes and parameters such as total biogenic amines, pH, TVB-N and microbial analysis with correlation coefficients larger than 0.98.

Fish freshness analysis using metallic potentiometric electrodes

One of the fields where the idea of developing artificial electronic mammalian sense devices might be widely applied is in food analysis. In this field, one very complex attribute yet of great importance is that of freshness. For instance, freshness is one of the most significant parameters of fish quality in most markets. The state of fish freshness can be assessed by various indicators but most of them are costly, time-consuming and lack of aptness for in situ or on site monitoring. This makes that the development of simple and undemanding systems for the evaluation of fish freshness is still an unresolved goal. Based on this demand, we focused our attention on the use of unselective sensors for the potential development of low-cost and easy-to-use devices for the estimation of freshness. After a preliminary study with a number of different electrodes, simple Au and Ag wires were used for the analysis of the evolution of sea (Sparus aurata) bream fish stored throughout time. PCA and neuronal network analyses showed that it is possible to determine the post-mortem time elapsed in minced gilthead sea bream using simple potentiometric measurements, suggesting that this method could be used for the analysis and evaluation of fish freshness. In order to somehow validate the potentiometric protocol for freshness assessment, the method has been compared with the determination of fish freshness based on the analysis of the concentration of certain bio-molecules as a function of time after the death of the fish. Among different possibilities the K1 index that simultaneously measures the variation in the ATP metabolites inosine 5′-phosphate (IMP), inosine (Ino) and hypoxanthine (Hx) was used. A remarkable correlation has been found between the K1 index determined during 7 days and the potentials of the Au and Ag electrodes.

A new method for the non-destructive determination of fish freshness by nuclear imaging

A new method for determining the freshness of harvested carp using nuclear imaging technology is presented. This research attempted to determine the freshness of carp by measuring the radioactive area increase (RAI) value of fish. The carp samples were maintained under refrigerated condition for 12 d, and RAI and total volatile base nitrogen (T-VBN) values were determined during the storage. The results showed that the RAI value increased with the T-VBN content during the storage. Also, there is a significant correlation between T-VBN content and RAI value of the carp kept in refrigerated condition. The results of this study suggest that the RAI value could be utilized to evaluate rapidly the freshness of carp.

Flow system for fish freshness determination based on double multi-enzyme reactor electrodes

A double reactor system for the determination of fish and shellfish freshness using the freshness indicator, K-value ( K={(HxR+Hx)/(ATP+ADP+AMP+IMP+HxR+Hx)}×100), was developed, where ATP, ADP, AMP, IMP, HxR and Hx are adenosine triphosphate, adenosine diphosphate, adenosine monophosphate, inosine monophosphate, inosine and hypoxanthine, respectively. The system consisted of a pair of enzyme reactors with an oxygen electrode positioned close to the respective reactor. The enzyme reactor (I) was packed with nucleoside phosphorylase and xanthine oxidase immobilized simultaneously on chitosan beads (immobilized enzyme A). Similarly, the enzyme reactor (II) was packed with immobilized enzyme A and immobilized enzyme B (co-immobilized alkaline phosphatase and adenosine deaminase). Moreover, this reactor consisted of two layers, the enzyme A and enzyme B (1:1). A good correlation was obtained between K values, which were determination by the proposed system and by the HPLC method. One assay could be completed within 5 min. The signal for the determination of K value of fish and shellfish was reproducible within 2.3%. The long-term stability of the enzyme reactors was evaluated at 30 °C for 28 days.

A New Approach for the Determination of Fish Freshness by Electrochemical Impedance Spectroscopy

ABSTRACT Changes in several dielectric parameters of carp, herring and sea bass during their storage after death at 4 °C, 15 °C and 25 °C were examined by electrochemical impedance spectroscopy (EIS) in the frequency range of 0.1 Hz to 100 kHz. This method offers a simple, rapid and in situ measurement of the onset of spoilage. The phase angle and admittance changes are the best freshness indicators, from which four classifications of freshness may be defined for all of the tested fish species. Warburg‐type impedance and CE (chemical reaction preceding an electrochemical reaction) processes were observed in the relaxation process during storage and a proposed equivalent circuit satisfactorily described the overall electrochemical behavior.

Development of a system with enzyme reactors for the determination of fish freshness

A continuous system for the determination of fish freshness with double enzyme reactors was developed and applied to the determination of the freshness indicator K K=100( HxR+ Hx)/( IMP+ HxR+ Hx), where IMP, HxR and Hx are Inosine monophosphate, Inosine and Hypoxanthine, respectively. The system was assembled with a three electrode screen-printed element (graphite as working electrode, silver as counter and silver, silver chloride as reference electrode) placed in a flow cell, a sample injection valve and two enzyme reactors. The determination of the total amount of HxR and Hx is realized by flowing the sample through two reactors in series: one reactor was packed with nucleoside phosphorylase (Np) and the other with xanthine oxidase (XO) immobilized on aminopropyl glass. Similarly, the other term of the equation was evaluated by flowing through the two reactors the sample treated by Alkaline phosphatase (AlP) for 5–10 min at 45°C. One assay could be completed within 5 min. The system for the determination of fish freshness was reproducible within 2–3% ( n=4). The immobilized enzymes were fairly stable for at least 3 months at 4°C. More than 200–300 samples could be analyzed in about one month by using these enzyme reactors provided the disposable screen-printed electrode should be changed every 30–40 real samples. The results obtained suggest that the proposed sensor system provides a simple, rapid and economical method for the determination of fish freshness ( K). We applied the present system with two reactors for the determination of K values in fish samples and compared the results with those obtained by the XO-reactor. Correlation factor and regression line between the two methods were 0.992 and Y=−3.14+1.03 X respectively. We concluded that the present flow injection analysis (FIA) system with XO and Np reactors was suitable as a simple, easy to handle and reliable instrument for quality control in the fish industry.

Amperometric sensor for fish freshness based on immobilized multi‐enzyme modified electrode

AbstractAn amperometric biosensor for the determination of fish freshness has been developed by immobilizing 5′‐nucleotidase (NT), nucleoside phosphorylase (NP) and xanthine oxidase (XO) enzymes on a Nafion‐paraquat chemically modified glassy‐carbon working electrode. The sensing principle is based on the oxygen consumption in the enzymatic reaction catalyzed by xanthine oxidase immobilized in the matrix. The quantity of hypoxanthine (Hx), the combined amount of inosine (HxR) and Hx and the total quantity of inosine 5′‐monophosphate (IMP), HxR and Hx can be determined, respectively, by changing the medium conditions. This sensor system can be used to determine the freshness of fish. An indicator of fish freshness, K1, is defined as K1 = {[HxR] + [Hx]}/{[IMP] + [HxR] + [Hx]}. This biosensor prowides a reliable means for determining of Hx, HxR and IMP in fish samples and the freshness of the fish meat.