1. 2 Vitamin Losses During Food Storage and Processing 16-June-2008.

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Vitamin Losses During Food Storage and

Processing

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Contents:

1 .Introduction

2 .Fat-soluble vitamins

3 .Water-soluble vitamins

4 .Simultaneous analysis of fat-soluble vitamins

5 .Analysis of vitamin C

6 .Conclusion

Vitamin Losses During Food Storage and Processing

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Introduction

Vitamins: Are organic compounds.

Are indispensable in very small amounts in the diet.

They have specific and individual functions to promotegrowth or reproduction, or to maintain health and life.

They regulate metabolic processes, control cellularfunctions, and prevent diseases, such as scurvy and rickets.

Introduction

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Introduction

Introduction

Vitamins are unstable in foods .Processing and cooking conditions cause vitamin loss. The losses vary widely according to cooking

method and type of food .

Vitamin degradation depends on specific parameters during the culinary process, e.g., temperature, oxygen, light, moisture,pH, and obviously length of exposure.

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Fat-soluble vitamins

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Water-soluble vitamins

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Due to the nutritional importance of the vitamins several analytical methodologies have been developed for determination of these substances

in food :

SpectrophotometrySpectroflurorimetryVoltametry

Chromatography…

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Simultaneous analysis of fat-soluble vitamins

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Why chromatography?

To determine more than one vitamin, the analytical method should be able to determine multi-components in complex samples.

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This method cannot be considered green, including the ones to determine fat-solublevitamins, due to the utilization of several organic solvents as mobile phase.

BUT

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To decrease the amount of toxic organic solvent, normally utilized in the chromatographic determination of fat-soluble vitamins.

strategy

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The stationary phase is a C18 column due to its popularity.

As the main goal was to develop green chromatographic method, all reagents selected as mobile phase component should be as nontoxic as possible.

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Structure of the fat-soluble vitamins

vitamin A

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vitamin E

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vitamin D3

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vitamin K1

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The vitamins A, E, D3 and K1 are hydrophobic .

High affinity by the selected stationary phase (C18 group)

Elution of Fat-soluble vitamins

1. Usage of high concentrations of methanol and acetonitrile

2 .Use of micelar medium

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The anionic SDS surfactant almost did not present absorption in the UV region and was selected as mobile and stationary phase modifier.

SDS : sodium dodecyl sulphate

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Micelar medium:


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SDS in concentrations higher than the critical micelar concentration (CMC, 0.24% (w/v)) as mobile phase:

Effect of the SDS in the separation of fat-soluble vitamins.

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SDS and ethanol in the mobile phase:

Effect of the ethanol in the chromatographic separation of fat-soluble vitamins.

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Effect of the butyl alcohol in the chromatographic separation of fat-soluble vitamins.

SDS and n-butyl alcohol in the mobile phase:

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It was possible to elute all the analytes in 70 min.

Optimization of the green chromatographic method:to improve the analytical frequency

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SDS and n-butyl alcohol in the mobile phase:


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Experimental conditions

pH

Temperature

Mobile phase flow rate

SDS concentration

Butyl alcohol concentration

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Constant

Factorial Experiment


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ExperimentButyl alcoholSDSFlow rate

110.0%) v/v(1.50%) w/v(1.5 mLmin−1

215.0%) v/v(1.50%) w/v(1.5 mLmin−1

310.0%) v/v(15.0%) w/v(1.5 mLmin−1

415.0%) v/v(15.0%) w/v(1.5 mLmin−1

510.0%) v/v(1.50%) w/v(2.0mLmin−1

615.0%) v/v(1.50%) w/v(2.0mLmin−1

710.0%) v/v(15.0%) w/v(2.0mLmin−1

815.0%) v/v(15.0%) w/v(2.0mLmin−1

Conditions of the factorial experiment to optimize the determination of the fat-soluble vitamins A, E, D3 and K1

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Effect of the mobile flow rate, butyl alcohol and SDS concentrations inthe chromatographic separation of fat-soluble vitamins.

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Result :

Experiment 8 led to the best result .

Quantifying the fat-soluble vitamins was possible in 25.0 min with retention times of 4.0, 9.6, 13.0 and 22.7 min to D3, A, E and K1 vitamins, respectively.


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Determination of fat-soluble vitamins with the proposed green chromatographic method. The results are expressed in mg L−1 ±S.D.


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Determination of fat-soluble vitamins in food and pharmaceutical supplement samples by the proposed green chromatographic method and by the conventional one

The results are expressed in mg g−1 ±R.S.D.a : Liquid sample and the results are expressed in mg L−1.

Comparison of green and conventional chromatography


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Analysis of vitamin C


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Vitamin C is considered as the most important water-soluble antioxidant.

The current RDA for ascorbic acid is suggested to be 100–120 mg/day to achieve cellular saturation and optimum risk reduction of heart diseases, stroke and cancer in healthy individuals.

RDA : recommended daily acceptance


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Evaluation of the effect of time and temperature on the content of vitamin C of two different

brands of pure orange juice by HPLC


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Months of storage18 ºC28 ºC38 ºC

Orange juice 1

0408.5

2385.4336.6265.6

4354.0302.0145.1

6333.0283.683.5

Orange juice 2

0361.5

2340.2311.3202.4

4303.5270.4127.4

6280.2244.263.1

Changes in the content of vitamin C measured by HPLC in orange juices during 6 months of storage at 18, 28 and 38 ºC (mg/L)


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Evaluation of the antioxidant activity of the orange juices by FRAP assay

FRAP : ferric reducing antioxidant power


Fe3+ Fe2+antioxidant

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Months of storage18 ºC28 ºC38 ºC

Orange juice 1

07.5

27.26.55.5

46.46.04.6

66.15.13.3

Orange juice 2

07.1

26.96.15.5

46.05.44.4

65.44.53.0

Changes in the antioxidant activity (FRAP mM) in orange juices during 6 months of storage at 18, 28 and 38 ºC


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Changes in (A) FRAP value in orange juice upon storage at: 18 ºC , 28 ºC and 38 ºC

Changes in (B) vitamin C in orange juice upon storage at: 18 ºC , 28 ºC and 38 ºC

Changes were calculated as the percentage of the values obtained for fresh juice.


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Conclusion:

Conclusion

Vitamin A is stable under an inert atmosphere; however,it rapidly loses its activity when heated in the presence of oxygen, especially at higher temperatures.

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Conclusion:

Conclusion

Retention of vitamin A in vegetables:household microwave steaming>frying > cooking without addition of water > cooking with the use of a large amount of water

There were no significant differences in vitamin A concentration among raw, pasteurized, and cooked milks.

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Conclusion:

Conclusion

Vitamin D is susceptible to the alkaline pH range, light, and heat .

Fat content is probably the crucial factor affecting retention during culinary treatment.

No losses were found during pasteurization and sterilization of milk or during production of dried or evaporated milk.

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Conclusion:

Conclusion

Retention of vitamin E in meats: roasting > frying > boiling

The losses of vitamin E in egg yolk during cooking:preparation, particularly by more drastic methods .

Vitamin E is unstable in the presence of oxygen, light, and even some unsaturated fats.

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Conclusion:

Conclusion

Vitamin K is destroyed by sunlight and decomposed by alkalis.

More vitamin K was retained when microwave heating was used.

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Conclusion:

Conclusion

Cooking losses of vitamin C depend on the degreeof heating, leaching into the cooking medium, surface area exposed to water and oxygen, pH, presence of transition metals, and any other factors

that facilitate oxidation .

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Conclusion:

Conclusion

Retention of vitamin C in vegetables:

Steaming>microwave technique>stir-frying with oil> pressure-cooking>conventional cooking, starting with boiled water> starting with cold water

Thawing before cooking causes more vitamin C loss.

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Conclusion:

Conclusion

Retention of vitamin B in meats:

microwave>frying>parching>steaming>boiling

Marinading of fish is the most damaging process.

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References:

1 .Journal of Food Composition and Analysis 19 (2006) 252–276

2 .Talanta 75 (2008) 141–146

3 .Journal of Food Composition and Analysis 20 (2007) 313–322

4 .Spectrochimica Acta Part A 65 (2006) 802–804

5 .Food Chemistry 100 (2007) 1220–1222

1. 2 Vitamin Losses During Food Storage and Processing 16-June-2008.

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Transcript of 1. 2 Vitamin Losses During Food Storage and Processing 16-June-2008.