LAB Report 1( Moisture) PDF

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FST306: FOOD ANALYSIS LAB REPORT 1: DETERMINATION OF MOISTURE STUDENT’S NAMES: 1. SITI NUR ALISSA BINTI AHMAD RASMAN (2019242842) 2. MUHAMMAD ADIB BIN MOHD KHALID (2019209238) 3. KHADIJAH HANEEZ BINTI ROSMADI (2019648028) 4. NURUL FAIZA BINTI RUSHDI (2019288712) LECTURER’S NAME: DR. SAFIYYAH BINTI SHAHIMI

1.0 INTRODUCTION One of the most important and widely used measurements in food processing and food testing is the determination of moisture. There are essentially several types of foods available for consumption on the market such as raw foods, processed foods and also modified foods. The objective of moisture content determination is to determine the moisture content of selected food samples using drying oven method and moisture analyzer. It is necessary to consider that the food is sufficient before consumption because the moisture contents affects the physical and chemical aspects of food that contribute to the freshness and stability of the food for a long period of time for storage. The actual quality of the food prior to consumption and subsequent processing by food producers in the food sector is determined by the moisture content. Basically, there are two different types on how to determine the moisture content in the food samples which is by using drying oven method and drying method by using moisture analyzer. In order to obtain more consistent temperature distribution in the oven, accurate measurements are carried out using force draft oven that circulate the air. Sample containing great deal of carbohydrates which will undergo chemical modification or volatile materials aside from water should not be dried in a exceedingly convection or force draft ovens. After a drying phase with infrared energy of the original matter previously weighed, the moisture analyser will calculated the remaining dry mass. Humidity is then measured in relation to the weight of the wet matter. The reduction of moisture in the material is seen on the monitor during the drying process. The moisture analyser is an excellent instrument for evaluating moisture and the amount of dry mass as well as the quality of highly reliable volatile and fixed substances. 2.0 METHODS • OVEN DRYING METHOD - Objective: To determine the moisture content of selected food samples using drying oven method. - Procedure: a) An aluminium dish was dried with cover for 4 hours in an oven at 105°C. The dish was transferred into the desiccator to let it cool and weighed after it had attained room temperature. b) 5g of homogenized sample was weighed approximately into the aluminium dish. c) The sample was placed uncovered in the oven overnight at 60°C or at 100°C - 105°C for 5 hours.

d) The lid was replaced while dish was still in the oven, the dish was removed from the oven. Cool in the desiccator and weighed soon after it had attained room temperature. The weight obtained was recorded. e) The drying process (step 3 and 4) was repeated until the constant weight was achieved. f) The percentage of moisture was calculated as described below. •

MOISTURE ANALYSER - Objective: To determine the moisture content of selected food samples using moisture analyser. - Procedure: a) The on/off button was pressed to switch on the moisture analyser. The air bubble in the level indicator was made sure to be centred. b) The test menu button was pressed and the drying parameter was set based on the following: Drying temperature: 150°C Profile: Standard Switch off time: 15 minutes Display set: % moist Target weight: 1g Program: Auto switch off c) The cover of the instrument was opened and cleared the pan. d) The empty sample pan was placed in the pan handler and placed the pan handler in the sample chamber. Ensured that the tongue of the pan handler fits exactly in the slot of the draft shield element and the sample pan lied flat in the pan handler. e) The tare button was pressed to set reading to zero. f) About 1g of sample was placed evenly distributed in the sample pan. The cover was closed. g) The start/stop button was pressed to start the drying process. h) At the end of the drying process, the result display for % moist was read and been recorded in the data sheet. i) The cover was opened and carefully lift the pan handler from the chamber to remove the sample.

3.0 RESULTS

Table 1.1: Determination of Moisture Data using Oven method Sample

Bread

Trial

Aluminium Initial dish + cover sample (g) weight (g)

Aluminium % Moisture dish + cover + dried sample

1

25.6778

5.02

28.9408

35.00

2

25.7761

5.06

29.0297

35.70

3

25.5998

5.04

28.8556

35.40

Mean±SD

Cheese

35.37±0.35

1

25.6554

5.03

28.8193

37.10

2

25.7001

5.00

28.8507

36.99

3

25.5887

5.07

28.7637

37.88

Mean±SD

37.32±0.3962

Table 1.2: Determination of Moisture Data Using Moisture Analyzer method Sample

Wheat flour

Milk powder

Trial

% Moisture

1

12.05

2

12.00

3

12.02

Mean±SD

12.02±0.0255

1

4.01

2

4.00

3

4.03

Mean±SD

4.01±0.0158

4.0 CALCULATION

Determination of moisture using oven method Bread: % moisture trial 1: (25.6778+5.02)−28.9408 (25.6778+5.02)−25.6778

× 100 = 35.00%

% moisture trial 2: (25.7761+5.06)−29.0297

(25.7761+5.06)−25.7761

% moisture trial 3:

× 100 = 35.70%

(25.5998+5.04)−28.8556

(25.5998+5.04)−25.5998

× 100 = 35.40%

Mean: 35.00+35.70+35.40 3

= 35.37

Standard deviation: 2 +(35.70−35.36)2 +(35.40−35.36)2

√(35.00−35.36)

3−1

=0.3513

Cheese: % moisture trial 1: (25.6554−5.03)−28.8193

(25.5664−5.03)−25.6554

× 100 = 37.10%

% moisture trial 2: (25.7001+5.00)−28.8507 (25.7001+5.00)−25.7001

× 100 = 36.99%

% moisture trial 3: (25.5887+5.07)−28.7637

(25.5887+5.07)−25.5887

× 100 = 37.88%

Mean: 37.10+36.99+37.88 3

Standard deviation:

= 37.32

2 +(36.99−37.32)2 +(37.88−37.32)2

√(37.10−37.32)

3−1

=0.3962 Determination of moisture using moisture analyzer method Wheat flour: Mean: 12.05+12.00+12.02 3

= 12.02

Standard deviation: √

(12.05−12.02)2 +(12.00−12.02)2 +(12.02−12.02)2 3−1

=0.0255

Milk powder: Mean: 4.01+4.0+4.03 3

= 4.01

Standard deviation: √

(4.01−4.01)2 +(4.00−4.01)2 +(4.03+4.01)2

=0.0158

3−1

5.0 QUESTION 1) Identify five (5) factors that you need to consider when choosing a moisture analysis method for specific food product. • the measurement principle • contact method • testing techniques • advantages and disadvantages • typical applications 2) In the drying oven method, why do you allow the sample to get cool before weighing? Because weighing the sample while it is hot will cause inaccurate measurements because as the sample cools, the weight fluctuates due to convection currents and give an incorrect measurement. 3) What are the advantages and disadvantages that you observed from the method conducted in this practical? OVEN DRYING METHOD ADVANTAGES • •

DISADVANTAGES

Several sample can be determined at the same time produces high accuracy result

•

•

requires extended heating periods and cooling phases, it means this method takes a few hours for the result. This method procedures are involving many manual steps. Therefore, the potential for error is high

DRYING METHOD (MOISTURE ANALYSER) ADVANTAGES • •

Fast measurement less than an hour Simple handling

DISADVANTAGES • •

Sample material may decompose or evaporate Only one measurement can be performed at one time

6.0 DISCUSSION The objective of this experiment is to determine the moisture content of selected food samples using oven drying method and moisture analyser. This oven drying method is a method that based on water evaporation in food samples. Under defined conditions, a known food sample weight is dried until constant weight is achieved. The weight loss in food sample after it is dried is equated with the moisture content of the food sample. On the other hand, the method of using moisture analyser is a measurement of moisture content based on thermogravimetric principle. Under controlled high heat conditions, the food sample placed on the sample pan is weighed and heated. Due to the heat produced by the halogen radiator, the water from food sample evaporates. The instrument will measure the weight loss and automatically determines the moisture percentage. In moisture analyzer method, we will be using MB45 Halogen Moisture Analyzer. In oven drying method, we will determine the moisture percentage bread and cheese. First, the aluminium dish and its cover need to be dried for 4 hours in an oven at 105◦C and then cool it to room temperature in the desiccator. The homogenized sample of bread and cheese will be weighed approximately 5g into the aluminium dish and then left the sample uncovered overnight for 5 hours at 100-105◦C. While the dish is still in oven, replace the lid and remove the dish from the oven. Then, cool it in desiccator and weigh it as soon as it attains room temperature then record the weight obtained. The drying process need to be repeated until it achieved the constant weight. Lastly, calculate the moisture percentage using formula stated: (𝑤𝑡 𝑜𝑓 𝑤𝑒𝑡 𝑠𝑎𝑚𝑝𝑙𝑒 + 𝑝𝑎𝑛) − (𝑤𝑡 𝑜𝑓 𝑑𝑟𝑖𝑒𝑑 𝑠𝑎𝑚𝑝𝑙𝑒 + 𝑝𝑎𝑛) × 100 (𝑤𝑡 𝑜𝑓 𝑤𝑒𝑡 𝑠𝑎𝑚𝑝𝑙𝑒 + 𝑝𝑎𝑛) − (𝑤𝑡 𝑜𝑓 𝑝𝑎𝑛) In the result table, we can obtain that cheese a higher percentage of moisture than bread which is 37.32% while bread is 35.37%. This shows that dairy product which is cheese contain more water than bread. In this experiment, the moisture is removed by evaporation since water has a lower boiling point than the other major components within food. To obtain a precise result, there are precaution steps we need to take and follow which is to weight the sample approximately and also repeat the drying process a few times in order to get precise result. In moisture analyser method, the experiment will be conducted using MB45 Halogen Moisture Analyser. In this experiment, we will be using wheat flour and milk powder as a food sample. First, turn on the moisture analyser and make sure that the air bubble in the level indicator is centred. Then, set the drying parameter for % moist at 150◦C for 15 minutes, 1 g for target weight, auto switch off for the program and set the profile at standard. Next, open the cover of the instrument

and clear the pan then put an empty pan in the pan handler that fits in the slot of the draft shield element and the sample pan lie flat in the pan handler. Sets the reading to zero by pressing tare button and then place about 1g of the food sample and make sure the sample are distributed evenly in the sample pan then close the cover. Then, start the drying process by pressing the start button and them when the drying process are done, read the result display for % moist and record the data. Remove the sample by opening the cover and lift the pan handler from the chamber. In the result collected, the moisture percentage of wheat flour is higher that milk powder which is 12.02% and milk powder is 4.01%. This shows that wheat flour contains more water than the milk powder. There are few practical considerations during removal of moisture we can include in this experiment. The first one is sample dimensions. The rate and efficiency of removal of moisture depends on particle size, distribution of particle size, sample size (how finely grounded it is) and surface area. This is because if the surface area increase, then the rate of moisture removal will increase. Next, the decomposition of other food components. When the drying temperature is too high or the drying process is carried out for too long, it might decompose some heat-sensitive components in food. This will cause a change in the mass of food matrix and also lead to errors in moisture content determination. Other than that, the temperature control. Drying methods use the specified drying temperature and time to dry the sample to standardize the process and achieve reproducible results. Lastly, the sample pans. Pan covers or lids is necessary to control and prevent sample from spattering which would lead to weight loss and result errors. Also, the pans should be handled with tongs since fingerprints might contribute to the mass of sample and to ensure there is no residual moisture is attached to the pans, it should be dried in an oven and placed in a desiccator prior to use. 7.0 CONCLUSION As a conclusion, this experiment run for determination of moisture by using oven drying method and moisture analyser method. From oven drying method we determine the moisture amount in the bread and cheese. The moisture content in cheese is higher than in the bread. From moisture analyser method, we determine the amount of moisture in wheat flour and milk powder. The moisture content in milk powder is lower than in the wheat flour. All the objective in this experiment is successfully obtained....