Fst 606 Pulsed Nmr.docx

FST 606 EXPERIMENT 1: DETERMINATION OF SOLID FAT CONTENT USING THE PULSED – NUCLEAR RESONANCE (NMR) SPECTROMETER

Prepared by

: ERNIE NAJWA NAJIHAH BINTI FAIDI

Student ID

: 2017283562

Group members

: 1.

NURUL FATINI BINTI MOHAMAD HALIMIN (2017405588)

2.

SITI NADIA BINTI JUMPAAN (2017405658)

3.

NUR NABILAH BINTI JOHARI (2017405596)

Group

: AS2465Q

Prepared for

: DR MARYAM BINTI HUSIN

Date of experiment

: 13TH MARCH 2019

Experiment 1: Determination of Solid Fat Content Using the Pulsed – Nuclear Resonance (NMR) Spectrometer

INTRODUCTION According to Fiedler, Mallin, & Vesci (2011), Nuclear Magnetic Resonance (NMR) was observed by Edward Purcell and Felix Bloch, independently, in 1946 when investigating the behavior of nuclei once placed in an external, uniform magnetic field and subject to a radio frequency (RF) magnetic field oriented perpendicular to the external field.

OBJECTIVES 1. To understand the principle of pulsed nuclear magnetic resonance 2. To determine the solid fat content of difference food samples (margarine, butter, shortening) at different set of temperature.

MATERIALS Pulsed – NMR (minispec MQ20, Bruker, Germany) Sample tubes (180 mm x 10 mm) Water bath (different temperature setting) SFC standards (0%, 30.6% and 72.7% SFC) Droppers Stopwatch Food sample: shortening, margarine, butter

METHOD 1. Standard Operating Procedure For Pulsed NMR The power for the magnet unit and PC was switched on before pressing ‘1’nat the back of the electronic controller. The PC was switched on and the ‘Bruker The

Minispec’ was clicked and the PC was waited to connecting the magnet unit. Next, the LED on both magnet and electronic unit were observed. Electric Control Unit Right LED, Connection status indicator: ON (green): PC communication to Electronic Control Unit OK OFF

: No communication of the Electronic Control Unit to PC.

Left LED, Status indicator: ON (green): Electronic Control Unit is working OFF

: Electronic Control Unit not working

Magnet Unit Right LED, indicates magnet temperature status: RED: preheating (fast mode) YELLOW: Transition to normal heating (air heat mode) GREEN: Temperature OK Left LED, connection status indicator: ON (green): Electronic Control Unit to Magnet Unit OK OFF: No communication between Electronic Control Unit and Magnetic Unit. The list of recent application was appeared, the top application was the latest, an application can be chosen from the list or click ‘setup’ and ‘browser’. The ‘Application Pool V5.2 Ratio’ was opened. Then customize was clicked, making sure the SFC analyser and Calibration permission were checked. OK was clicked again to proceed. After a while, the PC tried to communicate with the Minispec. The result appeared on the PC when the right LED on the control PC turned green. The temperature of the magnet unit has been making sure to stabilize by observing the right LED or clicking the instrument status. The daily check was performed.

2. Sample Preparation The sample used in this experiment was prepared a day earlier than the actual experiment. About 10 g fat samples were melted on a hot plate until the fats were clear with no suspended solids. It was then transferred into a glass NMR tubes while it was still hot, filling the tubes to a height of 4 cm. The tubes was then capped. No fats was ensure adhering to the outside of the tubes. Next, the samples were transferred into water bath at 60°C for 10 min and then at 0°C for 90 minutes interval. The instrument was then calibrated by measuring three standard sample of 0%, 30.6% and 72.7% solid respectively. After the holding time ended, the sample was next transferred into 10°C water bath for 30 minutes. After that, the samples were quickly removed from the water bath before letting it to dry and transferred to the measurement port on the pulsed – NMR. The samples was then transferred into 20°C water bath and was let for 30 minutes. The measurement was then repeated for 30°C, 40°C, 50°C and 60°. All the SFC result were obtained and printed for analyse.

Figure 1.1 shows the flowchart of the method in application of pulsed – NMR.

Figure 1.2 shows the sample preparation steps to determine the Solid Fat Content.

RESULTS Table 1.1 shows the data obtained by the pulsed – NMR spectrometer.

Table 1.2 shows the SFC obtained from the data analysis. Sample

Temperature (°C)

Margarine

Butter

Shortening

Solid Fat Content (% SFC)

Average ± S.D

Tube 1

Tube 2

Tube 3

10

46.526

47.982

45.429

46.646 ± 1.28

20

18.446

18.695

19.043

18.728 ± 0.30

30

8.52

8.441

8.615

8.525 ± 0.09

40

1.861

2.397

2.291

2.183 ± 0.28

50

0.427

0.134

-0.435

0.042 ± 0.44

60

0.145

-0.053

0.243

0.112 ± 0.15

10

46.573

46.201

45.39

46.055 ± 0.60

20

24.176

24.221

24.337

24.245 ± 0.08

30

10.853

10.742

11.312

10.969 ± 0.30

40

3.567

4.104

4.127

3.933 ± 0.32

50

0.055

-0.005

-0.041

0.003 ± 0.05

60

0.017

0.146

0.085

0.083 ± 0.06

10

72.669

72.962

73.496

73.042 ± 0.42

20

61.138

61.123

61.448

61.236 ± 0.18

30

32.819

32.439

33.082

32.78 ± 0.32

40

17.159

17.028

17.094

17.094 ± 0.07

50

7.673

8.391

8.667

8.244 ± 0.51

60

-0.038

-0.069

0.09

-0.006 ± 0.08

Figure 1.3 shows the graph of Solid Fat Content versus Temperature

Solid Fat Content VS Temperature 80

solid Fat Content (%)

70 60 50 40 30

20 10 0 -10

10

20

30

40

50

60

Temperature (°C) Margarine

Butter

Shortening

CALCULATION

Average percentage solid fat content (SFC) =

For margarine: 10°C =

46.526 + 47.982+ 45.429

= 46.646

3

𝑠𝑢𝑚 𝑜𝑓 𝑡𝑟𝑖𝑝𝑙𝑖𝑐𝑎𝑡𝑒 𝑝𝑒𝑟𝑐𝑒𝑛𝑡𝑎𝑔𝑒 3

Standard Deviation (S.D)

=√

∑(𝑥1− 𝑥)2 2

For margarine: 10°C = √

=√

∑(𝑥1− 𝑥)2 2

∑(46.526− 46.646)2+(47.982−46.646)2+(45.429−46.646)2 2

= 1.28

DISCUSSION Nuclear Magnetic Resonance spectroscopy is perhaps one of the most important scientific development since its first discover in the mid 1940’s. NMR has found a wide range of applications from solid state physics and materials science to chemical analysis and biophysics and also in food industries. NMR imaging has begun to attract the attention of food scientists since the distribution of water within an object can be measured non – invasively and changes with processing or storage can be followed (Colquhoun, 1993). NMR is divided into two main types which are Proton NMR and also Carbon NMR. Proton NMR is specialized in detecting only the hydrogen atom within the molecule meanwhile the carbon NMR is used in detecting the number and types of carbon atoms within the molecules. According to Colquhoun (1993), the solid fat content (SFC) and its temperature dependence are important factors governing the organoleptic properties of fat- based products. Although fat is an essential component in the human diet the excessive consumption of food with high fat content has been the major cause of obesity, one of the most serious human health problems in the modern developed world. Therefore, the fast precise determination of the fat content in raw and processed foods is an important analytical task (Manhas et al., 2015). Based on the graph obtained, shortening has the highest Solid Fat Content at the beginning of the experiment at 10°C followed by butter and margarine. The greater the heat applied to the fat, the lower the percentage of SFC of the substance. This is due to the

breakdown of the molecule bonding occurred during the heat treatment of the sample. However, all samples reach almost 0% of SFC at 60°C. There are some limitation due to the usage of the NMR spectrometer. First and foremost, the samples desired has to be sure to be a pure compound unless it will altered the result obtained and lead to errors in the experiment. Thus, the heating of the samples before running the test is crucial to get only the fat composition of the sample.

CONCLUSIONS This experiment was carried out to understand the principle applied to Pulsed Nuclear Magnetic Resonance (NMR) and to determine the Solid Fat Content (SFC) of three different food sample which are Margarine, Butter and also Shortening. Shortening has the most SFC content among the sample and SFC is decreasing when heat treatment is applied to the sample. The objectives of the experiment were successfully achieved.

REFERENCES Colquhoun, I. J. (1993). NMR Spectroscopy in Food Science. Fiedler, C., Mallin, D., & Vesci, A. (2011). Pulsed Nuclear Magnetic Resonance to Obtain Characteristic Times for Mineral Oil and Gycerin, (March), 1–3. Manhas, F., Pereira, V., Paula, A., Azevedo, J., Pallone, L., & Alberto, L. (2015). Throughpackage fat determination in commercial samples of mayonnaise and salad dressing using time-domain nuclear magnetic resonance spectroscopy and chemometrics. Food Control, 48, 62–66. https://doi.org/10.1016/j.foodcont.2014.02.028