Antioxident

PRESENTATION ON

“INFLUENCE OF COOKING METHOD

ON ANTIOXIDANT ACTIVITY OF FRUITS AND VEGETABLES”Miss Kanchan D. Deshmukh

ANTIOXIDANTS

INTRODUTIONAll people want to grow old healthy and fresh and to achieve that goal we can do some things the natural way to maintain a healthy body. Ways to extend life is to consume foods that contain Antioxidant.Fruits and vegetables are consider as major sources of Antioxidant, but various cooking method affects the antioxidant activity in different way.

HISTORY• Antioxidants were first introduce for industrial purposes in prevention of oxygen consumption eg. Prevent the corrosion of metal. • Till the late 30s, research on vitamin E led to the current understanding of antioxidants to protect human cells from damage.• During 1980s, many laboratories started to identify phytochemicals in plant that might be used as medicines. Many of these discovered phytochemicals seem to fight disease such as cancer, stroke, heart attack.

• Some nutrition researchers used antioxidants to prevent oxidation of unsaturated fat for the food.• From year 2000 onward, there are many more discoveries of phytochemicals in the fruits and vegetables which has high antioxidant substance. These phytochemicals (or also known as phytonutrients) are an emerging of health and nutrition.

An Antioxidant is a molecule that inhibits the oxidation of other molecules. OR

Antioxidants are compounds in food that neutralise Free Radicals.

OXIDATION

Oxidation is a chemical reaction that transfers electrons/hydrogen from a substance to an oxidizing agent. Oxidation in the human body produces chemicals called Free radicals

BROWNING

Browning has been atributed to air oxidation of phenolic substances present in most plant materials. Enzymes called polyphenolic substances present in plants and on exposure to air these are activated and initiate air oxidation and polymerization of phenolic compounds, producing a brown colour.

Oils and fats are particularly those rich in polyunsaturated fatty acid on exposure to air undergo oxidative decomposition , becoming viscous and giving a foul smell.

Oxidation can be accelerated by stress, cigarette smoking, alcohol, sunlight, pollution and other factor

FREE RADICALS

STAY AWAYFROM YOURENEMIE

• Free Radicals are chemically active atoms or molecular fragments that have a charge due to an excess or deficient number of electrons.

• One of the most frequent types of damage done to your body is caused by only Free Radicals.

Antioxidant

doing

Their

job

You are constantly exposed to the outside world Environmentally, Physically and Mentally. These factors cause Free Radicals.

• Examples of Free Radicals are the superoxide anion, hydroxyl radical, transition metals such as iron and copper, nitric acid and ozone. • Free Radicals arise from sources both inside (Endogenous) and outside (Exogenous) our bodies.

• Reactive Oxygen Species (ROS) - • Reactive Nitrogen Species (RNS) -

NO.• Reactive Metabolites or

Intermediates - metabolic activation of drugs, toxins, pollutants, cigarette smokes, etc.

TYPES OF FREE RADICAL

Diseases of the old – Chronic and degenerative diseases (diabetes, cataracts, Alzheimer’s disease, cancers, cardiovascular disease, and aging)

Diseases of the young and innocent -Acute and immature diseases

(Eyes: retinopathy of prematurity, Lung: bronchopulmonary displasia, Brain: cerebral pulsy, Pancreas: Type 1 diabetes)

FREE RADICAL- MEDIATED DISEASES

• Antioxidant Enzymes • Antioxidant Quenchers

• Antioxidant from Foods – nutrients/non-nutrients

FREE RADICAL DEFENCE SYSTEM

• In mitochondria: - generation of energy - ATP - glucose, fatty acids, amino acid - O2 2H2O

4e-

- leakage of O2-. (superoxide)

H2O2 (hydrogen peroxide)

SOURCES OF OXYGEN RADICAL

• In Smooth Endoplasmic Reticulum

(microsome)- detoxification (cytochrome P-450s)- toxins, drugs and xenobiotics- O2 + RH R-OH and H2O- leakage of O2

-.

- metabolic activation - X.

• In Peroxisomes

- containing oxidases for degradation of various substrates

- glucose, amino acids, xanthine, etc.

- requires O2

- by product is H2O2

• In Cytoplasm

- nitric oxide (NO.) production from Arginine - functions as a biological messenger - in brain, vascular endothelial cells, and macrophages

- NO. + O2-. ONOO.

(peroxynitrite)

Reactive oxygen species

Free Radical containing oxygen known as Reactive Oxygen Species,(ROS). ROS

hydrogen peroxide, H2O2

(Fenton´s reaction)hypochlorous acid, HClO

ozone, O3

singlet oxygen, 1O2

Free radicals superoxide, O2

· -

hydroxyl radical, OH ·

peroxyl, ROO ·alkoxyl, RO ·

hydroperoxyl, HO2 ·

ROS ROS also known as Free oxygen radicals Any molecule with an unpaired electron Extremely chemically reactive Damage cell membranes Responsible for more than 100 human diseases Aging, cancer, heart attacks, stroke and arthritis

• Primary source is our body during energy production• Environmental contaminants• Ionizing and ultraviolet radiation• Prolonged low blood flow states (atherosclerosis, heart attacks and stroke)• Diet (fatty and processed foods)• Low levels of antioxidants

HOW ARE ROS FORMED??

• Superoxide dismutase• Catalase• Glutathion• Antioxidants in diet• Supplementation

PROTECTION FROM ROS DAMAGE

Protecting Your cellMembrane from FREE RADICAL

OXIDATIVE STRESS.

Oxidative Stress occurs when the production of harmful molecules called Free Radicals is beyond the protective capabilities of the antioxidant defenses.

Insufficient levels of antioxidants, cause oxidative stress and may damage or kill the cells.

Oxidative Stress means unbalance between Pro-oxidant and Antioxidant mechanisms. This stress can be due to several factors as, exposure to pollutants, alcohol, medication, infection, poor diet, toxins, radiation etc.

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Disorder Associated With Oxidative Stress

Neurological• Alzheimers Disease• Parkinson‘s Disease

Endocrine• Diabetes

Gastrointestinal• Acute Pancreatitis

Others Conditions

• Obesity• Air Pollution• Toxicity• Inflammation This may lead to a wide range of human diseases most notably Heart diseases and Cancer.

Pollution. Ageing. Increase of Food consumption. Excessive physical exercise. Inflammation increases Free Radical production

RISKFACTORS OF FREERADICAL

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Examples of Antioxidants Include – Vitamin A Vitamin C Vitamin E Beta-carotene Lutein Lycopene Carotene Zinc Selenium Manganese Chromium

Antioxidant Rich Food

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What Harmful Effect will You Get Without Antioxidants?

Damage to your DNA Speed up the aging process Damage to cells Oxidation of LDL(bad cholesterol)

Damage

To

Your

DNA

Factors Affecting the Efficiency of Antioxidant:1. Activation energy of antioxidants to

donate hydrogen should be low.2. Oxidation potential should be high.3. Reduction potential should be low.4. Stability to pH and processing.5. Solubility in oil should be high.

Antioxidants Benefits

INFLUENCE OF COOKING METHODS ON ANTIOXIDANT ACTIVITY OF VEGETABLES

• Cooking such as boiling, baking, microwaving, pressure-cooking, frying, griddling can profoundly affect both the texture and nutritional value of vegetables.• Cooking softens the cell walls and facilities the extraction of carotenoids.• Some studies have shown that a loss of vitamins in vegetables during cooking varies with cooking treatment.

• Vegetables contain several hydrophilic and lipophilic antioxidant compounds and most of the vegetables are consumed after being cooked.

Thus, it is important to know what happens to their antioxidant activity or free radical capacity during common domestic processes (boiling, frying, micro Wave cooking).

Boiling Pressure cooking

Microwave cooking(mediumpower)

Baking Grinding Frying

Vegetables Time(min)Artichoke 10 4 3 20 13 10Asparagus 17 5 4 39 18 12Beetroot 24 5 2.5 30 15 8Broad bean 20 5 4 30 14 10Broccoli 16 5 2 49 20 15Brussels sprout 22 5 2 35 18 14

Carrot 23 5 3 35 17 10Cauliflower 17 5 2.5 34 20 13

Celery 20 4 3 20 20 10Eggplant 16 4 3.5 38 10 10Garlic 20 4 2.5 30 12 8Green bean 21 4.5 3 35 15 15Leek 15 3 2 30 12 8Maize 47 10 2 40 10 7Onion 20 5 3.5 35 17 12Pea 12 4 4 25 10 6Green Pepper 20 5 4.5 47 17

Spinach 13 3 2 14 18 12Swiss chard 20 3 3.5 30 15 10

Zucchini 20 4.5 4 24 15 10

Table 1: Cooking methods and cooking time use to cook vegetables.

• The vegetables were purchased on 5 different occasions in local supermarket and were from different lots.

• After cooking, the vegetables were cooled for a few minutes at room temperature before being ground, homogenised, and hydroxyl radicals and Trolox equivalent antioxidant capacity (TEAC) methods to evaluate their free radical scavenging and Antioxidant capacity.

Hydroxyl Radical Scavenging • ROS have been suggested to cause structural alterations in DNA, for eg. Damage bases and damage to deoxyribose and protein DNA cross-links.• ROS are able to directly modify DNA bases, including hydroxyl radical and peroxyl and alkoxyl radicals.• Where as superoxide and hydrogen peroxide do not react with DNA bases directly

ABTS radical cation scavenging activity

This method is base on the inhibition, by antioxidants, of the absorbance of the radical cation 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) or ABTS which has a characteristics long-wavelength absorption spectrum showing a maximum at 734 nm.Antioxidant compounds suppress the absorbance of the antioxidant capacity of the ABTS radical cation to an extent and on a time scale dependent on the antioxidant capacity of the substance.

Free Radical Scavenging Assays

1. Antioxidant activity expressed as scavenging of lioperoxyl radical

Table 2. shows the inhibition of lipid peroxidation in the presence of vegetables submission to different cooking treatments, such as boiling, pressure-cooking, baking, microwaving, griddling, frying

% losses

Cooking losses

Vegetables Boiling Pressure-cooking Baking Microwaving Griddling Frying

Artichoke --- A --- --- --- −7.0 ± 2.18yz ---Asparagus −6.7 ± 1.56z --- --- --- --- 6.5 ± 1.08bcBeetroot 5.0 ± 0.85bc --- 19.6 ± 1.16e 22.0 ± 1.55d 8.0 ± 1.42def 21.4 ± 0.88efBroad bean 9.7 ± 0.69bc 6.8 ± 0.60c 10.5 ± 1.09d 10.4 ± 0.72c −6.5 ± 1.66yz 11.8 ± 1.15cdBroccoli 32.7 ±2.65fg 37.4 ± 1.66de --- 34.2 ± 0.60e 35.1 ± 1.32g 15.6 ± 1.03deBrussels sprout 33.0 ±1.67fg 38.9 ± 2.19def 31.8 ± 0.84f 40.3 ± 1.50fg 11.8 ± 0.78ef 42.4 ± 0.83iCauliflower 55.0 ± 1.08ij 36.7 ± 0.61d 36.4 ± 1.06g 56.7 ± 1.55h 13.7 ± 2.04f 23.9 ± 0.47fCarrot 33.9 ±1.45fg 43.7 ± 1.37fg 31.7 ± 1.92f 42.2 ± 0.96g --- 11.1 ± 1.47cdCelery 21.2 ± 1.17d 34.3 ± 1.57d 11.2 ± 1.09d 30.7 ± 2.10e --- 18.9 ± 3.28efEggplant --- −6.4 ± 2.24z −8.7 ± 2.11xy −6.7 ± 2.34z --- −8.4 ± 3.15zGarlic 32.5 ±1.38fg 38.9 ± 1.15def 19.9 ± 1.41e --- −14.6 ± 3.06x 15.5 ± 1.79deGreen beans 40.0 ± 2.54h 25.9 ± 2.36d −12.4 ± 2.00x 33.0 ± 0.44e 9.1 ± 2.56def ---

Leek 36.1±2.06gh 43.3 ± 1.78ef 34.6 ± 1.77fg 36.3 ± 1.68ef --- 30.7 ± 2.44gMaize 23.1±1.95de 26.4 ± 2.00d −8.6 ± 1.06xy −8.5 ± 1.38z −5.6 ± 1.25yz 9.5 ± 1.74cd

Onion --- --- 10.1 ± 0.44cd --- 34.7 ± 1.16g 34.6 ± 1.20ghPea 60.5 ± 1.42j 34.5 ± 1.04d 38.7 ± 0.86g 34.7 ± 1.05ef 6.6 ± 2.29de 38.2 ± 1.40hiPepper 27.9 ±0.69ef 24.5 ± 1.23d --- −9.8 ± 3.15z 42.9 ± 1.40iSpinach 31.6 ±1.81fg 18.3 ± 1.39d −6.0 ± 1.71yz --- −10.0 ± 1.50xy 7.8 ± 1.54bcSwiss chard 10.8 ± 1.09c --- −8.0 ± 1.93xy −6.4 ± 1.81z −10.2 ± 1.34xy ---Zucchini 51.2 ± 1.35i 49.5 ± 0.51g 47.5 ± 1.72h 36.2 ± 1.11ef 13.1 ± 1.59ef 60.9 ± 1.71j

Table 2

Above 50% losses (highest) Around 30% to 50% Between 5%and 30%Table 3 shows ABTS radical scavenging capacity for cooked vegetables expressed by TEAC value.

% lossesCooking losses

Vegetables Boiling Pressure-cooking Baking Microwaving Griddling Frying

Artichoke --- A --- --- --- --- ---Asparagus --- --- --- --- --- 37.9 ± 2.84bcBeetroot --- --- --- --- --- ---Broad bean --- --- --- --- --- ---Broccoli --- --- --- --- --- ---Brussels sprout --- --- --- --- --- ---Cauliflower --- --- --- --- --- 17.5 ± 2.75abCarrot −66.7 ± 15.61y −79.8 ± 16.35x -111.1 ± 23.68y −142.2 ± 26.84y −191.1 ± 25.06y −191.2 ± 25.41x

Celery −37.3 ± 13.81z −43.1 ± 9.26y 149.6 ± 20.69 −167.0 ± 18.43y −167.2 ± 18.79y −154.7 ± 18.10yEggplant --- --- ---- --- --- ---Garlic 59.1 ± 3.83c 59.3 ± 3.08e 59.4± 2.55b --- 35.5 ± 3.96b 58.2 ± 2.02cGreen beans --- −10.6 ± 4.71z −57.8 ± 6.99z −57.2 ± 7.42z −53.4 ± 6.70z −53.6 ± 8.33zLeek --- 35.9 ± 4.40cd --- --- --- ---

Maize --- 23.5 ± 3.15cd --- 35.0 ± 3.20b --- ---Onion --- --- --- --- --- ---Pea --- --- --- 6.1 ± 1.43ab --- ---Pepper --- --- --- --- --- 20.5 ± 3.16abSpinach 11.1 ± 1.77ab --- --- --- --- ---Swiss chard --- 18.6 ± 2.94bc --- --- --- 14.0 ± 3.85abZucchini 28.5 ± 3.11b 39.3 ± 1.68d --- --- --- ---

Table 3

Conclusion• The results showed that artichoke was the only vegetable that maintain its very high scavenging lipoperoxyl radical capacity in all the cooking methods. • Beet root , green bean, and garlic kept their OH antioxidant activity after most cooking treatment. • Among the vegetables that increased their TEAC values were green bean, celery and carrot after all cooking methods(except green bean after boiling). These 3 types showed less ABTS radical capacity.

• Depending on the vegetable in question, griddling and microwave cooking produced the lowest losses, while pressure-cooking and boiling lead to the greatest losses; in general frying occupies an intermediate position.• The results of the study serve as a data base providing information on the effects of different cooking methods on the antioxidant potential of the vegetables, and might encourage the food industry to recommended particular cooking methods to help to maintain the antioxidant properties of vegetables that we eat.

THANKYOU

So, start living healthier by consuming foods and fruits that have many benefits for the body of both short and long term and take care.