Freshness Determination From Poultry Meat With Photocolorimeters Biology Essay

In Europe, the mean loss in measure of fresh domestic fowl meat is estimated to be 1 & A ; Ntilde ; 3 % , although some processing workss describe up to 6 % trimming loss in breast meat entirely. At 1 % loss, it can be estimated that 54,600 metric tons of premier broiler meat was lost during the twelvemonth 1996. In December 1996, the manufacturer monetary value ( lb sterling ( & A ; lb ; ) equivalent ) was 56 p kg-1 in the Netherlands, the lowest cost manufacturer in Europe, and at this manufacturer monetary value, the existent loss for the twelvemonth 1996 can be estimated at over & As ; lb ; 30 million. If the retail monetary value of fresh Meleagris gallopavo meat is considered to be & amp ; lb ; 3 kg-1 and the minimum loss due to paring happens to be 1 % , so it is estimated that the European Meleagris gallopavo industry had lost about & A ; lb ; 50 million worth of premier meat in the twelvemonth 1996. Although the fixingss and downgraded parts or carcases would hold been sold at a decreased monetary value, this surely shows the importance of carcase and meat quality.

To turn to the concerns of domestic fowl processors and retail merchants, scientists around the universe are unrelentingly prosecuting research and development. ( A.B.M. Raj, 1997 )In meat and meat merchandises during storage at refrigerated temperatures can develop a extremely toxic substances such as ammonium hydroxide, H sulphide, peroxidase, putrescine, and cadaverine formed by decarboxylation of aminic acids in meat as a effect of the procedure autolytic decomposition procedure in meat.Qualities measurings of chemical or physico-chemical belongingss, which are straight relevant to nutrient quality, are found less often for procedurecontrol in the meat industry ( Nollet, L. M. L.

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Et Al. 2006 ) To measure the quality and freshness of meat during storage was determined ammonia ( easy hydrolyzable N ) with Nessler reagent. Method consists in step the measure of nitrogen nowadays in the signifier of dissolved ammonium hydroxide and ammonium ions. The trial involves dosing in the reaction medium with Nessler ‘s reagent ( solution of K tetraiodomercurate ) Photocolorimetric method.The merchandises were purchased from the slaughter house instantly after slaughter and stored for 10 yearss at 4 0 C.

Materials and Method

Sample PreparationMeat for analysis was minced twice after that was weighed 10 gms ( 10,000 milligram ) of the analytical balance and placed in a 100 volumetric flask and brought to volume with bidistilate H2O closed and with a palpebra to agitate and go forth to rest for 10 proceedingss.Sample PreparationAmmonia in aqueous infusion of meat sample signifier with solution of K tetraiodomercurate ( II ) ( K2 [ HgI4 ] ) ( Nessler reagent ) composite colored, yellowish-orange oximercury ammonium iodide, colour strength was read photocolorimeter to the wavelengths of 425 nanometers.NH4+ + 2 [ HgI4 ] 2? + 4OH? > HgO·Hg ( NH2 ) I + 7I? + 3H2OReagentsBidistilate H2O without ammonium hydroxide.Nessler reagent ( tetraiodomercurate bipotasic solution in K hydrated oxide ) : 5 g K iodide dissolved in 5 cm3 of hot H2O in an Erlenmeyer flask.

Add hot saturated solution of mercurous chloride until the precipitate formed is no longer dissolved. After chilling the solution separate, pour a 100 cm3 volumetric flask. Add 15 g K hydrated oxide dissolved in 30 cm3 H2O and convey to volume with H2O. Add 0.5 cm3 saturated solution of mercurous chloride, allow to do the solution above the precipitate and separated by decantation, base on balls in a clean and kept in the dark.

Alkaline mixture: 10 g Na carbonate and 10 g Na hydrated oxide dissolved in few milliliter of bidistilate H2O in a 100 milliliter volumetric flask and completed to volume with bidistilate H2O ;Standard stocks solution of ammonium hydroxide is obtained by weighing the analytical balance 1000 milligram ammonium chloride dissolved in a 100 volumetric flask, conveying to volume with bidistilate H2O after a dilution is made by taking 1 milliliter of this solution and presenting it into a 1000 milliliter volumetric flask and conveying to volume with bidistilateH2O so that the solution eventually have a concentration of 0.01 milligrams / fifty ammonium chloride.Seignette salt ( potassium Na tartrate ) : 392g salt SeignetteNaKC4H4O6 a?™ 4:20 dissolve in 784 milliliters 20 % NaOH solution. Mix good and after two hours may be used without agitating the bottle.Description of working processs100 milliliters aqueous meat infusion were placed in a cylinder with a stopper and add 1 ml alkalic mixture and shaken. It was the supernatant 10 milliliter, was added 2 ml Seignette salt and 2 milliliters Nessler reagent was shaken and left to stand 10 proceedingss subsequently which was centrifuged at 3500 revolutions per minute for 10 min with a revolving extractor ROTANTA theoretical account 460 so read colour strength in WTW photocolorimeter SpectroFlex theoretical account 6100 to 425 nanometers in 1 millimeter cuvette. Extinction values of the sample was interpolated from a criterion curve which was performed after the strategy of Table no 1.

Table 1. Standard solution realisation for photocolorimeter standardization

Concentration of ammonia solution









standard solutionmilliliter024680Bidistilate H2Omilliliter086421Seignette saltmilliliter2Nessler reagentmilliliter2Figure 1. Calibration curveTable 2. Consequences of standard solution readings at photocolorimeterStandard solution concentrations ( milligram )Abs.1*Abs.2*MediaRSD**


00,0020,0020,00200,020,1560,1550,1550,4540,040,2870,2820,2841,2420,060,4360,4340,4350,3250,080,5530,5550,5540,2550,10,6710,6730,6720,210* Absorbance ; ** Relative criterion divergence

Consequences and Discussion

During the 10 yearss in which meat was kept at 4 0 C was taken each twenty-four hours 10 g sample which was analyzed for ammonium hydroxide content by reaction of ammonium hydroxide with Nessler reagent.The strength of colour formed following reaction likewise to the standard solution of ammonium hydroxide reading. Extinction values of the sample was interpolated on the standardization curve.

In the tabular array one can see the consequences content additions of the ammonium hydroxide in meat during the 10 yearss.Table 3. Consequences of experimental informations


Sample multitudes g







milligram NH3/ 100 g

110,0180,1050,1040,1050,67623,484210,0220,1410,1420,1420,49924,736310,0250,1720,1740,1730,81726,509410,0020,1850,1860,1860,38126,942510,0080,2010,2020,2020,35029,229610,0030,2150,2160,2160,32831,399710,0130,2240,2270,2260,94035,824810,0160,2430,2470,2451,15437,224910,0110,2680,2620,2651,60037,2421010,0100,2750,2730,2740,51638,212* Absorbance ; ** Relative criterion divergenceFrom Table 3 we can see that the meat from of the 9th twenty-four hours the value exceeds the bound from 35 milligram, g NH3/100 permitted by Rumanian statute law, bound stipulated in article 12 of Order 975/1998 which provides that in the porc meat the easy hydrolyzable N over 35 milligrams NH3/100 g bound is unfit for human ingestion through clear marks of impairment ( Order 975 1998 )Variation of hydrolysable N ( mg NH3 /100g meat ) during storage to de 40C can be seen in Figure 2.Figure 2 Variation of hydrolysable N ( mg NH3 /100g meat ) during storageto de 40C


The finding of ammonium hydroxide ( easy hydrolyzable N ) in porc meat is critical for day-to-day quality control of production and for specification in contracts.

The traditional ammonium hydroxide methods ( easy hydrolyzable N ) see. SR 9065-7: 2007 is comparatively accurate, but it is, time-consuming ; exposes the analyst to toxic exhausts, concentrated acid, and base ; and produces chemical wastes that must be disposed compared with Photocolorimetric method of this paper which is slightly quicker than the traditional method SR 9065-7: 2007.


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