FST_____
TITLE OF EXPERIMENT: ____________ ____________________ ______________ _____________ _____________ _____________ ______________ _____________ __________ ____ Introduction (4M) Methods (2 M) Results (4M) Discussion (4M) onclusion (!M) Re"erences (#M) For$%t (2M) TOT&L (2'M)
N&ME N&ME
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TDE TDENT NT ID
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*RO *ROP P
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D&TE OF EXPERIMENT: ________________________________________________ D&TE OF +MIION : ________________________________________________
FST_____ Introduction
The moisture content of food is important to food manufactures for a variety of reasons. Moisture is an important factor in food quality, preservation, and resistance deterioration. Determination of moisture content also is necessary to calculate the content of other food constituents on a uniform basis (dry weight basis). The dry matter that remain after moisture analysis is commonly referred to as total solids. The simplest method to measure moisture content is based on gravimetric where the loss of weight due to water evaporation is calculated. This can be accomplish using air oven, vacumm oven, convection oven or other sophiscated instruments such as infared lamp, halogen radiator and microwave energy. An instrument such as Moisture Analyser used in this eperiment operates on the thermogravimetric principle. This instrument first measure the initial weight of sample and then the sample is quic!ly heated by an integral halogen dryer unit to vapori"e the water. During the drying operation, weight of sample is continuously determines until at the completion of drying, result is displayed as percent moisture content. #ther methods for moisture determination include distillation and chemical methods. Distillation methods are particularly useful for foods of low moisture content and products containing volatile oils such as herbs and spices, since the oils remain dissolve in the organic solvent. $owever , distillation methods have often been reported to give low values and the use of flammable solvents pose a small but significant ha"ard . %n chemical reaction method such as &arl 'isher, water content is determined by titration. This method is not suitable for foods or high moisture content. %t is applicable to foods that give eeratic results when heated or placed under vacumm for eample dried foods and vegetables, oils, candies and chocolate. egardless of the measurement used, the quality of moisture determination is based on the sample preparation and the used of correct parameters ( for eample sample si"e, type of smple, drying temperature and drying time).
FST_____ 1.0 OVEN DRING METHOD.
#bective * To determine the moisture content of selected food samples using drying oven method. Apparatus * Aluminium dish, analytical balance, drying oven, dessicators and spatula Method * +) An aluminium dish with cover for hours is dried in an oven at +- -/. The dish is transferred into the dessicator to let it cool and the dish is weighed after it has attained room temperature. 0) g of homogeni"ed is weighed approimately into the aluminium dish. 1) The sample which is an uncovered is placed in the oven overnight at 2--/ or at +--3+--/ for hours. ) The lid is replaced while dish is still in the oven, the dish is removed from oven. %t is cooled in dessicator and weigh soon after attaining room temperature. The weight is recorded . ) The drying process( step 1 and step ) are repeated until constant weighed is achieved. 2) The percentage of moisture is calculated.
2.0 DRYING METHOD ( MOISTURE ANALYSER )
#bective* To determine the moisture content of selected food samples using moisture analyser. Apparatus * M4 $alogen Moisture Analyser ( #haus /orporation ), sample pan and spatula. 5rocedure* +. The ONO!! button is pressed to switch on the Moisture Analyser. The air bubble is ma!e sure in the LEVEL INDI"ATOR is centred.
0. The TEST MENU button is pressed and the drying parameter is set based on the following*
FST_____ Drying Temperature * +- -/ 5rofile * 6tandard 6witch #ff Time * + minutes Display 6et * 7 moist Target weight * +g 5rogram * Auto switch3off 1. The cover of the instrument is opened and the pan is cleared. . An empty sample pan is placed in the pan handler and the pan handler is placed in the sample chamber. The tongue of the pan handler is ensured fits eactly in the slot of the draft shield element and the sample pan lie flat in the pan handler. . The TARE button is pressed to sets reading to "ero. 2. + g of sample is placed and it is evenly distributed in the sample pan. The cover is closed, 8. The STARTSTO# button is pressed to start the drying process. 9. At the end of the drying process, the result display for moist 7 is read and the reading is recorded in Data 6heet. :. The cover is opened and the pan handler is carefully lifted from the chamber to remove the sample.
FST_____ esults* Table +.+ * Determination of Moisture Data ;sing #ven Method 6ample
4iscuits
#ats
Trial
Aluminium dish
+ 0 1 Mean + 0 1 Mean
0.2:+ 8.:1+ 0.828 +.-+81 0.98+ 1.-282 0.91:2 0.:0+
%nitial sample Aluminium dish weight (g) < cover < dried sample (g) .+-92 .::-1 .-00 0.-+ .--10 8.28-: .-8 .1982 .-0-+ 8.9+.--21 8.8++ .--2.21 .-+-+ 8.1::9l
7 Moisture
1.97 0.087 +.:7 +1.017 -.07 8.+: 7 0.+27 +-.207
Table +.0 * Determination of Moisture Data ;sing Moisture Analy"er Method 6ample 4iscuits
#ats
Trial + 0 1 Mean + 0 1 Mean
7 Moisture 9.9 9.81 :.8: :.-+-.-+ +0.0+-.9 ++.-0
=ample /alculation ;sing #ven Method To Determine 5ercentage of Moisture (>eight of wet sample< pan) ? ( >eight of dried sample
eight of wet sampleeight of pan)
(0.2:+<.+-92)3 .::-1 +--7 @ 1.97 (0.2:+<.+-92) ?0.2:+
FST_____ Discussion * #ven Drying method * #ven drying method is widely used in determination of moisture. >ater is removed due to heating at +- /. Boss of weight due to vapori"ation of water is ta!en as weight of moisture. %n this eperiments, we have as!ed to determine the percentage of moisture for biscuits and oats. 'or biscuits, the percentage of moisture (mean) that we obtained is +1.017. The value ( +1.017) can be accepted as the typical biscuits commonly as have low moisture content and rather low value of water activity. Then, the percentage of moisture( mean) that we get for oats is +-.207 . 4y comparing to biscuits, we can say that percentage of moisture is slightly higher than oats and this shows us that the accuracy of moisture determination is affected by several factors which are, drying temperature, relative humidity, particle si"e of sample, handling method of sample, amount of sample, type of evaporation dish, variation in temperature inside the oven. The precaution also be ta!en during the eperiment to minimi"e any erros happen such as sample should be dried in stainless steel containers, which is not decompose during heating and the weighing process of aluminium dish should be cool for 1- minutes after dried for certain periods in oven must be followed to avoid overestimation readings. Moisture Determination Method * Moisture Analyser is one of the tools that we applied to determine of moisture for biscuits and oats. 'or biscuits and oats respectively, the percentage of moisture is :.--7 and ++.-07. ;nfortunately, we find that the readings for both sample is not consistent such as for 1 rdtrial for biscuits, there is increment of readings which from 9.817 to :.8:7 , it should be range 9 of something and for 0nd trial for oats, the readings is increase suddenly from +-.-+7 to +0.0-7. Although, the method are very easy and it only need + minutes, we believed some erros may happen which are the moisture analy"er is not to be cooled for temporarily after get the result for first trial which affected the second reading or third reading and students not distribute the sample evenly in moisture analy"er cause the results for moisture determination is inconsistent and inaccurate as it disturbed some part in loss of weight of sample process.
Cuestions *
FST_____ +. %dentify five () factors that you need to consider when choosing a moisture analysis method for a specific food product. a) b) c) d) e)
=pected moisture content ature of other food constituents =quipment availability Accuracy and precision 5urpose
0. %n the drying oven method, why do you allow the sample to get cooled before weighingE %t is because the balance in calibrated to wor! at a specific temperature, if the obect being weighed transfers heat into the balance pan it will heat things up. Metal epands and contracts with different temperature, even a slight temperature change can cause enough change in distance of internal components to get bad reading. Another is the air. The heat will transfer to the air. %f the balance is in a enclosures (which it should be to remove any variations do to air current), when the temperature of the air increases the pressure inside the closed container will increaseF pushing down more on the balance pan throwing off the reading. 1. Discuss some possible errors involves in using distillation method. 5lacing the thermometer too high will lead to a low value for boiling point 3 be sure all the mercury in the bulb is below the sidearm of the still head. %nadequately clamping the apparatus can be dangerous. #ver clamping can be a problem, since it causes stress in the apparatus. efer to the Distillation section for detail on clamping the apparatus in place and clamping the pieces together. %t is especially important to tighten the nut which !eeps the utility clamp from rotating. #ther than that, formation of emulsions between the water and the solvent which difficult to separate and adherence of water droplets to the inside of the glasswares.
. Does the pigment in the toluene from analysis of turmeric powder represent moistureE =plain. No. because the pigment in the toluene is oil which is lipid.
FST_____ . >hat are the advantages and disadvantges tat you observed from the methods conducted in this practical. The advantages that % observed from the eperiments are the method are suitable to be applied to food that has low moisture content. 'uthermore, methods are easy to setup and operate. The method also officially aproved for many applications. #therwise, there are still disadvantages such as the destructive effect of method applied. The time ta!en for the results to be collected for oven drying method is too long. 6ome method are not applicable to some types of food
/onclusion* The percentage of moisture content in oats and biscuits have been successfully determined using drying oven method and moisture analyser. eferences +.
https://en.wikipedia.org/wiki/Moisture _ analysis https://en. wikipedia.org/ wiki/Water _ content.
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Food Analaysis Laboratory Manual, Diploma or Food !echnology pro"ided by Aishah #u$ang. 2.
%. ielsen, 6.6. (0-+-). 'ood Analysis th =dition. &pringer &cience ' #usiness Media 5ublication.
