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

2016 ◽  
Vol 79 (4) ◽  
pp. 635-645 ◽  
Author(s):  
HONGBING FAN ◽  
XIAOCHANG LIU ◽  
HUI HONG ◽  
SONG SHEN ◽  
QIAN XU ◽  
...  

ABSTRACT 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.

2012 ◽  
Vol 47 (1) ◽  
pp. 93-98 ◽  
Author(s):  
M Begum ◽  
MA Khaleque ◽  
MA Wahed ◽  
F Hafiz

With a view to get a pen picture about the trend and extent of quality changes and as well as shelf life of the head off and head on shrimp (Macrobrachium rosenbergii, De Man, 1879), the present study have been carried out . Quality changes have been measured by application of sensory score evaluation and changes in chemical indices such as Total Volatile Nitrogen (TVN) value, pH and level of moisture at different time interval and Total Bacterial Count (TBC) at 15°C during the study period. The results of the sensory score evaluation indicates that the shrimp quality decreased to the limits of acceptability at 12th days of ice storage. The head off shrimp kept slight better than corresponding head on shrimps. The bacterial counts determined at 15°C have been found to increase from 103 - 107 and 104 -108 cfu/gm for head off and head on shrimp respectively at the limit of acceptability. The moisture level increased from initial 78.85gm% to final 83.80gm% (head off) & 79.0gm% to 84.0gm% (head on) and pH value increases from 7.1 to 8.1 during the whole period of iced preservation . Both head off and head on shrimp remained in acceptable condition for up to 12 and 14 days of storage respectively while the quality of fish deteriorates and become unacceptable. The bacterial count corresponding to unacceptable condition ranges from 108-109 cfu/gm fish sample. The TVN value corresponding to rejection condition were 45-50mg N/100gm fish sample. DOI: http://dx.doi.org/10.3329/bjsir.v47i1.10731 Bangladesh J. Sci. Ind. Res. 47(1), 93-98, 2012


2014 ◽  
Vol 159 ◽  
pp. 20-28 ◽  
Author(s):  
Hongbing Fan ◽  
Yongkang Luo ◽  
Xiaofei Yin ◽  
Yulong Bao ◽  
Ligeng Feng

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).


2012 ◽  
Vol 239-240 ◽  
pp. 1573-1576
Author(s):  
Zhu Qing Gao ◽  
Xiao Dong Cai ◽  
Kai Cheng Ling

At different temperatures, the protonation constants of tannic acid and the complex apparent stability constants between tannic acid and VO2+ were determined by using pH potentimetric method. The results showed that the protonation constants and the complex apparent stability constants slightly decreased with the raising temperature. In accordance with the pH value in the tannin extract technology, the conditional stability constants of the complex were calculated on the basis of the acid effect of tannic acid and the hydrolysis effect of VO2+. It was found that pH greatly affected the stability constants of the complex , so pH must be strictly controlled in the tannin extract technology.


2005 ◽  
Vol 73 (3) ◽  
pp. 147-161 ◽  
Author(s):  
Charumanee S. ◽  
Weiss-Greiler P. ◽  
Wolschann P. ◽  
Viernstein H. ◽  
Titwan A. ◽  
...  

Thermodynamic studies of piroxicam in aqueous solution complexed with β-cyclodextrin (β-CD), γ-cyclodextrin (γ-CD) and two β-cyclodextrin derivatives, hydroxypropyl-β-cyclodextrin (HP-P-CD) and methyl-β-cyclodextrin (Me-β-CD) were performed at different temperatures and pH values using the phase solubility method. The phase solubility diagrams of β-CD, γ-CD and HP-β-CD is of AL-type behavior, indicating the formation of 1:l complexes. The related stability constants range from β-CD > γ-CD > Me-β-CD > HP-β-CD, respectively. An Ap-type solubility diagram is observed for Me-β-CD, indicating the formation of 1:2 complexes at higher CD concentrations. From the temperature dependence of the equilibrium constants the reaction enthalpies and entropies have been determined. The contributions of the reaction entropies are small and no enthalpy-entropy-compensation is observed, except for γ-CD, where a very small negative reaction entropy could be estimated. Moreover, the influence of the pH value is rather high because the differently charged forms of piroxicam show different solubility behavior in water.


2013 ◽  
Vol 7 (4) ◽  
pp. 175-180 ◽  
Author(s):  
Liga Dabare ◽  
Ruta Svinka

Porous ceramic pellets for possible environmental application were produced from different Latvian clays by sintering at different temperatures. Their characteristics and influence of additives were analysed using X-ray diffraction, mercury porosimetry and BET tests. The obtained ceramic pellets from calcareous clays after immersion in distilled water change its pH value, which affects their capability to adsorb ions or molecules on the surface. The sorption capabilities are dependent on the pH level of water solution, composition of clays, and used adsorbate. Porosity of the produced pellets is mostly within range from 15 to 25 % throughout all sintering temperatures with a slight decrease at 1050 ?C. The specific surface area has a wide range up to 30 m2/g. The highest surface area has pellets sintered at lower temperatures. The adsorption capability of pellets was evaluated using water solutions with different ions. The most promising results were obtained with iodine sorption. For most pellets the sorption capacity was 12.7 mg/g, although for the pellets sintered at 1050 ?C it was lower.


2017 ◽  
Vol 21 (2) ◽  
pp. 63-72 ◽  
Author(s):  
Yunfeng Hu ◽  
Zengyu Wei ◽  
Yuanyuan Chen

AbstractIn this paper, the quality changes of fresh dumpling wrappers during storage were studied by measuring the changes of microbial growth, color, pH, texture, cooking property, moisture content and distribution of raw dumpling wrappers. The correlation of these indicators was analyzed. The results showed that the dumpling wrappers had generated lots of microorganisms during storage and the pH value decreased gradually. The dumpling wrappers had browning and the color became darker. The texture of the dumpling wrappers changed obviously. The original structure of raw dumpling wrappers were destroyed, the water distribution is uneven and migration to the surface. The apparent index of raw dumpling wrappers has a significant correlation with the internal change, which provides a certain guiding significance for maintaining the good quality of dumpling wrappers.


1996 ◽  
Vol 13 (6) ◽  
pp. 527-536 ◽  
Author(s):  
L.J. Alemany ◽  
M.C. Jiménez ◽  
M.A. Larrubia ◽  
F. Delgado ◽  
J.M. Blasco

The present work examines the possible use of fly ash, a byproduct of coal power stations, as a means of removing phenol from water, or equivalently, of restricting its movement in solid wastes or soil. Equilibrium experiments were performed to evaluate the removal efficiency of fly ash. The adsorption experiments were undertaken using fly ash treated at three different pH levels and with three different temperatures. The results indicate that although phenol can be removed from water, this depends markedly on the temperature and pH value of the treatment solution employed.


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