RADIATION AND PHYTOCHEMICAL PRODUCTION By Maria … · radicals resulting of the lipid peroxidation and oxidized DNA base,whose reactions are important in the pathogenesis of cancer

RADIATION AND PHYTOCHEMICAL RADIATION AND PHYTOCHEMICAL PRODUCTIONPRODUCTION

ByByMaria Alexandra MorenoMaria Alexandra Moreno

College Station, April 2002 College Station, April 2002

BACK GROUNDBACK GROUND

Flavonoids are natural constituents in plant foods and Flavonoids are natural constituents in plant foods and important components in human dietimportant components in human dietStudies have started to investigate the relationship Studies have started to investigate the relationship between diet and cancer between diet and cancer It has been found that polyphenol flavonoids exhibit a It has been found that polyphenol flavonoids exhibit a wide range of biological, pharmacological and chemo wide range of biological, pharmacological and chemo protective proprietiesprotective proprietiesFlavonoidsFlavonoids act as a free scavengers preventing oxidation act as a free scavengers preventing oxidation and cancer initiation.and cancer initiation.

Irradiation and Irradiation and PhitochemicalPhitochemical ProductionProduction

QuercetinQuercetin,one of the most abundant,one of the most abundantflavonoidsflavonoids,can act increasing the inactivation and ,can act increasing the inactivation and excretion of carcinogens or by reducing oxidative excretion of carcinogens or by reducing oxidative damage of DNA target cellsdamage of DNA target cellsIrradiation has been applied for extending the Irradiation has been applied for extending the postpost--harvest life of fruits and vegetablesharvest life of fruits and vegetablesPrevious studies reported that gamma irradiation Previous studies reported that gamma irradiation influences theinfluences the flavonoidflavonoid content in fruits and thecontent in fruits and thepolyphenolicpolyphenolic compounds in mushrooms.compounds in mushrooms.

FLAVONOIDSFLAVONOIDS

PolyphenolicPolyphenolic compoundscompoundsCommon flavon nucleusCommon flavon nucleusComposed of benzene rings Composed of benzene rings Ubiquitous in plants Ubiquitous in plants ((flavonolsflavonols,, flavanonesflavanones, , flavanols flavanols and and flavansflavans))QuercetineQuercetine present in tea, present in tea, coffee,cocoa,cereal, grains coffee,cocoa,cereal, grains and a variety of fruits and and a variety of fruits and vegetables.vegetables.

FLAVONOIDSFLAVONOIDS

AnthocyaninsAnthocyanins are other group are other group ofof flavonoidsflavonoids which are which are responsible to pigmentation in responsible to pigmentation in some fruits and vegetables.some fruits and vegetables.Their biosynthesis are otherTheir biosynthesis are otherflavonoidsflavonoids andand phenolicphenolic acids acids that are also antioxidants.that are also antioxidants.The average intake ofThe average intake offlavonoidsflavonoids is about 1g, of this is about 1g, of this about 170 mg are counted for about 170 mg are counted for flavones andflavones and flavonolsflavonols. .

Antioxidant Activity ofAntioxidant Activity of FlavonoidsFlavonoids

Flavonoids show cancer chemo preventive effects Flavonoids show cancer chemo preventive effects because their antioxidant propriety.because their antioxidant propriety.They act as a scavengers of the oxygen free They act as a scavengers of the oxygen free radicals resulting of the lipid peroxidation and radicals resulting of the lipid peroxidation and oxidized DNA base,whose reactions are oxidized DNA base,whose reactions are important in the pathogenesis of cancer , and can important in the pathogenesis of cancer , and can cause damage at this molecules.cause damage at this molecules.The position and the number of hydroxyl groups The position and the number of hydroxyl groups in flavonoids are responsible of their in flavonoids are responsible of their antioxidative activity.antioxidative activity.

Effect of Irradiation on Effect of Irradiation on FlavonoidsFlavonoids

The effectiveness of irradiation in the preservation of The effectiveness of irradiation in the preservation of fruits and vegetables differs according to the specie.fruits and vegetables differs according to the specie.Some of the changes are associated with the alteration in Some of the changes are associated with the alteration in some enzymatic activities.some enzymatic activities.The formation of flavonoids requires light stimulus, The formation of flavonoids requires light stimulus, which induces the enzymes responsible of flavonoid which induces the enzymes responsible of flavonoid biosynthesis,and provides the various substrates for the biosynthesis,and provides the various substrates for the rapid production of flavonol glucosides. rapid production of flavonol glucosides. Irradiation emits its effect at some metabolic prior to Irradiation emits its effect at some metabolic prior to flavonoid synthesis. flavonoid synthesis.

Biosynthesis of Biosynthesis of FlavonoidsFlavonoids

The phenylalanine ammoniaThe phenylalanine ammonia lyaselyase (PAL) catalyzes the(PAL) catalyzes thephenoylalanine phenoylalanine to 4to 4--coumaroylcoumaroyl--CoACoA and then it is and then it is converting toconverting to flavonolflavonol end products.end products.

Effect of gamma irradiation in fruits and Effect of gamma irradiation in fruits and vegetablesvegetables

Dose rate = 4.5 kGyh-¹Storage at 4°C/17 daysOne sample with metabisulfitepH differential method (concentration of anthocyanin)

Cobalt-601.03.06.09.0

GRAPE POMACE

Dose rate = 6 kGyh-¹Storage at 3-4°C/49 daysHPLC analysis.

Cobalt-600.3CITRUS CLEMENTINA

Storage at 20-24°C/24 hr HPLC Analysis (determination flavonoids).

OTHER CONDITIONS

Cobalt-60

SOURCE

0.81.2

DOSE (kGy)

ONIONS(red,yellow,pink,and white)

PRODUCT

Effect of Gamma IrradiationEffect of Gamma Irradiation

In diced onions the In diced onions the aglyconaglycon content and content and quercetin quercetin content content increase in all increase in all genotypes,except in genotypes,except in white,at both doses.white,at both doses.The higher increase The higher increase was at 0.8 was at 0.8 kGykGy.

Diced onionsDose Aglycone Quercetin

TotalRed onions 0.00 0.73 164.76

0.80 13.60 229.061.20 12.77 179.00

Pink onions 0.00 0.17 150.400.80 15.15 167.891.20 5.75 146.47

Yellow onions 0.00 0.15 132.860.80 15.40 187.131.20 12.28 160.04

White onions 0.00 ND ND0.80 ND 0.181.20 ND 0.14

.

Effect of gamma irradiation on aglycone and total quercetin(mg/kg fresh wt)


There is a higher increase inThere is a higher increase in aglyconaglycon content thancontent thanquercetinquercetin content after radiation.content after radiation.

Figure 4. Aglycone Content in Irradiated Diced Onions

0.00 5.00 10.00 15.00 20.00

0.00

0.80

1.20

Dos

es (K

gy)

Aglycone( mg/kg fresh wt)

Red Pink Yellow White


Figure 5. Total Quercetin Content in Irradiated Diced Onions

0.00 50.00 100.00 150.00 200.00 250.00

0.00

0.80

1.20

Dos

es (K

gy)

Total Quercetin (mg/kg fresh wt)



In whole onions bulbs In whole onions bulbs all genotypes showed all genotypes showed an increase in an increase in quercetin quercetin content at both content at both doses,but the higher doses,but the higher increase was at 0.8 increase was at 0.8 kGykGy..AglyconAglycon content content increase slightly after increase slightly after radiation.

Whole onions Bulbs Dose Aglycone Quercetin

TotalRed onions 0.00 0.17 122.54

0.80 0.53 274.791.20 0.54 163.02

Pink onions 0.00 0.14 108.270.80 0.97 152.631.20 1.25 112.61

Yellow onions 0.00 0.15 99.940.80 0.20 159.861.20 0.25 135.79

White onions 0.00 ND 0.190.80 ND 0.961.20 0.16 1.71radiation.

Effect of gamma irradiation on aglyconcontentand total quercetin(mg/kg fresh wt)


All genotypes showed an increase inAll genotypes showed an increase in quercetinquercetin content content at both doses,but the higher increase was at 0.8at both doses,but the higher increase was at 0.8 kGykGy..

Figure 6.Aglycone Content in Irradiated Whole Onions Bulbs

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40

0.00

0.80

1.20

Dos

es (K

gy)

Aglycone( mg/kg fresh wt)



Figure 7. Total Quercetin Content in Irradiated Whole Onions Bulbs

0.00 50.00 100.00 150.00 200.00 250.00 300.00

0.00

0.80

1.20

Dos

es (K

gy)

Total Quercetin (mg/kg fresh wt)



In the case,of Citrus In the case,of Citrus clementinaclementina,the results ,the results showed an increase in the showed an increase in the total total phenolic phenolic compounds, with a compounds, with a maximum content of 21 maximum content of 21 days of storage.days of storage.The PAL activity was The PAL activity was significantly higher in significantly higher in irradiated samples irradiated samples compares with control compares with control samplessamples..


In the case of grape In the case of grape pomacepomace, irradiation , irradiation increased the increased the anthocyanin anthocyanin content, and the best content, and the best concentration was concentration was obtained at 6 obtained at 6 kGy kGy dose, dose, and adding sulfite.and adding sulfite.

CONCLUSIONCONCLUSION

Gamma irradiation both low (0.8,1.2, and 3.0 Gamma irradiation both low (0.8,1.2, and 3.0 kGykGy) and ) and high doses (6 high doses (6 kGykGy) in combination with lower ) in combination with lower temperature, improves the temperature, improves the flavonoids flavonoids content in fruits and content in fruits and vegetables by the induction of chemical changes vegetables by the induction of chemical changes stimulated by the PAL activity in the biosynthesis of this stimulated by the PAL activity in the biosynthesis of this compounds.compounds.This increase can be beneficial considering the This increase can be beneficial considering the chemopreventive chemopreventive effects of these effects of these flavonoids flavonoids implicated as implicated as dietary antioxidants in foods, and also important for dietary antioxidants in foods, and also important for extending the storage time.extending the storage time.

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RADIATION AND PHYTOCHEMICAL PRODUCTION By Maria … · radicals resulting of the lipid peroxidation and oxidized DNA base,whose reactions are important in the pathogenesis of cancer