Hui Hong

Effects of different freezing treatments on the biogenic amine and quality changes of bighead carp (Aristichthys nobilis) heads during ice storage

The effects of different freezing treatments on the quality changes of bighead carp heads were evaluated in terms of pH value, TBARS, TVB-N, K-value, biogenic amine, total aerobic counts (TACs), drip loss, cooking loss and electrical conductivity (EC) during ice storage. Fish heads were stored at -40°C (T1), -40°C for 12h and then -18°C (T2), -18°C (T3) for 3months prior to ice storage. No significant differences were observed among T1, T2 and T3 for drip loss, cooking loss and EC (p>0.05). T2 showed lower TACs, pH value, TBARS and TVB-N than T3 did. Significant lower value of spermine and spermidine were observed in T1, T2 and T3 than those of control group (fresh) from 9th to 18th day (p<0.05). Drip loss was significantly correlated with TBARS, pH value, TVB-N, and TACs in groups T1, T2 and T3 (p<0.05).

Effects of salt concentration on biogenic amine formation and quality changes in grass carp (Ctenopharyngodon idellus) fillets stored at 4 and 20 °C.

The effects of different salt concentrations on the quality changes of grass carp (Ctenopharyngodon idella) fillets were evaluated in terms of biogenic amines, adenosine triphosphate and its related compounds, sensory attributes, total volatile basic nitrogen (TVB-N), and total viable counts during 4 and 20 °C storage. Grass carp fillets were brined in solutions of 2% NaCl (T1) and 10% NaCl (T2), and unsalted carp fillets were used as controls (CK). T1 and T2 showed higher sensory scores than CK. According to the TVB-N values, CK, T1, and T2 could maintain the freshness of carp for approximately 9, 12, and 27 days, respectively, when stored at 4 °C. The higher salt concentration had better inhibitory effect on the accumulation of some biogenic amines, such as tryptamine (TRM), 2-phenylethylamine (PHE), putrescine (PUT), and cadaverine (CAD). TVB-N of untreated grass carp fillets showed a significant (P < 0.05) correlation with TRM, PHE, PUT, and CAD during storage. PUT and CAD showed a significant (P < 0.05) correlation with TVB-N for T2 at 20 °C and T1 at 4 °C.

Effects of different stunning methods on the flesh quality of grass carp (Ctenopharyngodon idellus) fillets stored at 4 °C.

The effects of stunning methods (percussion (T1), stunning at -22 °C in a freezer (T2), and immersion in ice slurry (T3)) on the flesh quality of grass carp fillets were evaluated in terms of K-value, total volatile base nitrogen (TVB-N), electrical conductivity (EC), total viable counts (TVC), biogenic amines, and sensory scores during storage. Moreover, fillets were analyzed periodically for pH, hardness, acid phosphatase activity, and the content of glycogen, adenosine triphosphate (ATP), and lactate. Significantly slower ATP depletion, slower reduction in pH, slower lactate formation, and higher initial glycogen level were observed in T3 compared to T1 and T2 (P<0.05). Grass carp stunned by percussion showed higher TVB-N, EC, TVC, total biogenic amines, and lower sensory scores. Significantly lower TVC (P<0.05) was exhibited in T3, which indicated that stunning in ice slurry could improve the quality and prolong the shelf life of grass carp.

Quality Changes and Biogenic Amines Accumulation of Black Carp (Mylopharyngodon piceus) Fillets Stored at Different Temperatures

Postmortem quality changes of black carp (Mylopharyngodon piceus) fillets stored at 20, 4, and 0°C (in ice) were determined in terms of pH value, K value, total volatile basic nitrogen, free amino acids, biogenic amines, drip loss, electrical conductivity (EC), sensory score, and microbial growth. The results showed that black carp fillets could maintain a good quality for 2, 9, and 12 days when stored at 20, 4, and 0°C, respectively. Pseudomonads, Aeromonas, and Enterobacteriaceae were the main spoilage bacteria in black carp. Tryptamine, 2-phenylethylamine, putrescine, cadaverine, and tyramine increased significantly (P < 0.05) during storage at the three temperatures, but not spermidine and spermine, among which tyramine and putrescine were the main biogenic amines in black carp fillets. A significantly higher concentration of histamine (132.05 mg/kg on the third day) was detected in the samples stored at 20°C (P < 0.01) than at 4 and 0°C (0.62 to 3.28 mg/kg) throughout storage, indicating storage of samples at 20°C favored the formation of histamine. The accumulations of tyramine, cadaverine, and histamine were highly correlated with the productions of tyrosine, lysine, and histidine, respectively. Correlations between EC and sensory, physical, chemical, and microbial parameters at the three storage temperatures showed that EC could be used as a better quality indicator to assess the overall quality of fish stored at 4 and 0°C (low temperature) than at 20°C.

Comparison between the Arrhenius model and the radial basis function neural network (RBFNN) model for predicting quality changes of frozen shrimp (Solenocera melantho)

ABSTRACT Changes in quality indices [total volatile base nitrogen (TVB-N), salt extractable protein (SEP), hypoxanthine (Hx), K-value, sensory assessment (SA), and electrical conductivity (EC)] for shrimp (Solenocera melantho) stored at −28, −20, and −12°C for 112 days were investigated in this study. The Arrhenius model and the radial basis function neural network (RBFNN) model were established to predict changes in the quality of shrimp during storage. Quality of shrimp stored at −12°C changed more quickly during 56–112 days, but those stored at −28°C deteriorated slowly during the entire storage period. Additionally, the indicators SEP, EC, and SA all fitted to the Arrhenius model well (relative errors within ±10%), but this model did not perform well in the prediction of K-value, Hx, and TVB-N on some days. However, the RBFNN model showed excellent accuracy for all indicators (relative errors within ±0.5%). The RBFNN model performed better than the Arrhenius model in predicting the quality of shrimp stored at −28°C to −12°C.

Study on Gel Properties of Silver Carp (Hypophthalmichthys molitrix) and White Croaker (Argyrosomus argentatus) Blended Surimi at Different Setting Conditions

Gel properties of blends of surimi from silver carp and white croaker set for a range of times and at different temperatures were evaluated for breaking force, breaking distance, and whiteness. Total protein content was 12% in all samples, and the concentration of white croaker surimi protein in the blends was designed at 0, 10, 20, 30, and 40%. The blended surimi had greater gel strength than either of the two types of surimi alone. Breaking force and breaking distance after setting were also significantly higher than that of the blended surimi cooked directly without setting. The blended surimi exhibited less modori than either of the two types of surimi alone heated to 50°C. The whiteness values of the blended surimi were significantly higher than that of white croaker alone. These results indicate there are advantages to be gained in utilizing surimi from freshwater silver carp in blends with surimi from marine captured white croaker which is becoming limited in supply.

Effect of glazing and rosemary (Rosmarinus officinalis) extract on preservation of mud shrimp (Solenocera melantho) during frozen storage

In this study, glazing with water and rosemary (Rosmarinus officinalis) extract were applied on frozen mud shrimp (Solenocera melantho) and stored at -20 °C for 24 weeks. Quality loss and protein and lipid changes of shrimp were evaluated by total volatile basis nitrogen (TVB-N), drip loss, moisture distribution, sulfhydryl content (SH), disulfide bond, intrinsic fluorescence intensity, lipid content, free fatty acids (FFA), peroxide value (PV), fluorescent compounds and sensory characteristics. Results showed that unglazed mud shrimp exhibited significant quality decline after 16 weeks of frozen storage. Glazing treatment significantly reduced quality loss, protein degradation, and lipid oxidative damage of shrimp during the 24 weeks of frozen storage, compared to the unglazed control sample. Glazing with rosemary extract was more effective in controlling quality changes in frozen mud shrimp with lower TVB-N, drip loss, PV, FFA and higher lipid content and sensory scores.

Gel properties of silver carp (Hypophthalmichthys molitrix) and chicken mixture gels as affected by setting temperatures

ABSTRACT This study aimed to evaluate the effect of setting temperatures (30°C, 35°C, 40°C, 45°C, and 50°C) on gel properties and protein profiles of paste gels derived from silver carp (Hypophthalmichthys molitrix) and chicken meat. The mixture composed of 50% (w/w) chicken meat and 50% (w/w) silver carp meat, and the three paste gels, were assessed based on color, gel strength, TPA, water distribution, chemical interactions, and SDS-PAGE. Chicken gels had better gel properties and a higher content of immobilized water than the mixture or fish gels, regardless of setting conditions. On the other hand, an appropriate setting temperature for the three paste gels promoted aggregation of the myosin heavy chain (MHC) and the formation of hydrophobic interactions and disulfide bonds, which resulted in superior gel properties. Pre-incubation at 40°C enhanced gel properties of fish meat, but pre-incubation at 45°C and 50°C were appropriate for achieving better gels for the mixture and chicken, respectively. These results indicated that there is the potential to obtain mixed products and new meat products by utilizing chicken and fish meat that have improved gel properties.