Chilling Injury and Browning of Fresh-cut Fruits and ... · Chilling Injury and Browning of Fresh-cut Fruits and Vegetables ... Document Document ... • Browning can be prevented

Chilling Injury and Browning of Chilling Injury and Browning of FreshFresh--cut Fruits and Vegetablescut Fruits and Vegetables

ChienChien Yi WangYi WangProduce Quality and Safety LaboratoryProduce Quality and Safety Laboratory

Plant Sciences InstitutePlant Sciences InstituteU. S. Department of AgricultureU. S. Department of Agriculture

Beltsville, Maryland 20705Beltsville, Maryland 20705U. S. A.U. S. A.

Fresh-cut

ConvenientConvenientFreshFreshGood flavorGood flavorNutritiousNutritious

12 Billion dollar industry 12 Billion dollar industry annually in the United Statesannually in the United States..

Fresh-cut

Fresh-cut

ChallengesChallenges

What are the challenges?What are the challenges?What kind of problems we can What kind of problems we can encounter?encounter?What kind of approaches we can What kind of approaches we can use to alleviate the problems?use to alleviate the problems?Are those approaches safe?Are those approaches safe?

BrowningBrowning and and decay decay are two of the most are two of the most serious problems in serious problems in freshfresh--cut Products.cut Products.

•• Wounding and oxidation cause an Wounding and oxidation cause an increase in metabolic activities increase in metabolic activities and lead to rapid browning of the and lead to rapid browning of the cut surfacecut surface

•• Sulfite compounds (e.g. sodium Sulfite compounds (e.g. sodium bisulfitebisulfite, potassium , potassium metabisulfitemetabisulfite) were banned for ) were banned for use on fresh fruits and use on fresh fruits and vegetables by FDAvegetables by FDA

•• Alternatives: Other GRAS Alternatives: Other GRAS substances or naturally occurring substances or naturally occurring compoundscompounds

Digging for Answers

Natural Products as AntiNatural Products as Anti--browning browning AgentsAgents

•• CysteineCysteine or or acetylcysteineacetylcysteine –– An An inhibitor of inhibitor of polyphenolpolyphenol oxidaseoxidase(the key catalytic enzyme in (the key catalytic enzyme in browning reaction.)browning reaction.)

•• Ascorbic acid or Ascorbic acid or isoascorbateisoascorbate –– A A reducing agentreducing agent

•• 44--Hexylresorcinol Hexylresorcinol –– A competitive A competitive inhibitor of inhibitor of polyphenolpolyphenol oxidaseoxidase..

AntiAnti--browning Treatmentbrowning Treatment

ApplesApples acetylcysteineacetylcysteine + + isoascorbateisoascorbate+ 4+ 4--hexylresorcinol + calciumhexylresorcinol + calciumpropionatepropionate

BananasBananas acetylcysteineacetylcysteine + citric acid+ citric acidMangoesMangoes isoascorbateisoascorbate + 4+ 4--

hexylresorcinol + potassiumhexylresorcinol + potassiumsorbatesorbate

Peaches Peaches isoascorbateisoascorbate + 4+ 4--exylresorcinolexylresorcinol + potassium + potassium sorbatesorbate

AntiAnti--browning Treatmentsbrowning TreatmentsPearsPears isoascorbateisoascorbate + 4+ 4--

hexylresorcinol + potassiumhexylresorcinol + potassiumsorbatesorbate

PineapplesPineapples ascorbic acid or ascorbic acid or isoascorbateisoascorbatePotatoesPotatoes acetylcysteineacetylcysteine + 4+ 4--

hexylresorcinol + citric acidhexylresorcinol + citric acidRadishesRadishes acetylcysteineacetylcysteine + 4+ 4--

hexylresorcinol + potassiumhexylresorcinol + potassiumsorbatesorbate

Sweet Sweet PotatoesPotatoes acetylcysteineacetylcysteine + citric acid+ citric acid

Fresh - cut Apple Slices

FreshFresh--cut Apple Slicescut Apple Slicesacetylcysteineacetylcysteine+ + isoascorbateisoascorbate

+ 4+ 4--hexylresorcinol hexylresorcinol + calcium propionate+ calcium propionate

FreshFresh--cut Peach Slicescut Peach Slices

FreshFresh--cut Peach Slicescut Peach Slicesisoascorbateisoascorbate

+ 4+ 4--hexylresorcinolhexylresorcinol+ potassium + potassium sorbatesorbate

FreshFresh--cut Banana Slicescut Banana Slices

FreshFresh--cut Banana Slicescut Banana Slices

acetylcysteineacetylcysteine+ citric acid+ citric acid

ororglutathioneglutathione+ citric acid+ citric acid

FreshFresh--cut Sweet Potatoescut Sweet Potatoes

FreshFresh--cut Sweet Potatoescut Sweet Potatoes

acetylcysteineacetylcysteine+ citric acid+ citric acid

FreshFresh--cut Mango Slicescut Mango Slices

FreshFresh--cut Mango Slicescut Mango Slices

isoascorbateisoascorbate+ 4+ 4--

hexylresorcinol hexylresorcinol + potassium + potassium

sorbatesorbate

FreshFresh--cutcutPineapplePineappleSlicesSlices

Dec

ay in

dex

1

2

3

4

5

Acc

epta

bilit

y1

3

5

7

9

ControlAIA 0.1 MAC 0.05 MAA 0.05 M

A

B

Inedible

Freshly-cut

Limit ofmarketability

Very good

Limit ofusability

None

Up 50% surfaceaffected

5 to 20% surface affected

20 to 50% surfaceaffected

Up to 5% surfaceaffected

Days at 10°C

7 14

Bro

wni

ng in

dex

1

2

3

4C

MYTHMYTHFreshFresh--cut products do cut products do not have chilling injury not have chilling injury problem.problem.FreshFresh--cut products are cut products are less susceptible to less susceptible to chilling injury.chilling injury.

FACTSFACTS•• FreshFresh--cut products are as sensitive to cut products are as sensitive to

chilling injury as intact producechilling injury as intact produce•• Chilling injury symptoms are not evident Chilling injury symptoms are not evident

because of the removal of skin which because of the removal of skin which carries the visible symptomscarries the visible symptoms

•• The affected tissues can develop offThe affected tissues can develop off--flavor or offflavor or off-- odor which are not visibleodor which are not visible

•• Chilling temperatures can weaken Chilling temperatures can weaken chillingchilling--sensitive tissues and cause them sensitive tissues and cause them to be more susceptible to physiological to be more susceptible to physiological and pathological deteriorationand pathological deterioration

Alleviation of Chilling Alleviation of Chilling Injury in FreshInjury in Fresh--CutCut

Decay induced by Decay induced by chilling injury can be chilling injury can be Reduced by UVReduced by UV--C C irradiationirradiation

UV-C Treatment of Mango Slices

UV-C

Chilling injury can also be Chilling injury can also be reduced by treatment reduced by treatment with GRAS (Generally with GRAS (Generally Recognized as Safe) Recognized as Safe) substances, such as substances, such as methyl methyl jasmonatejasmonate..

MJ Reduces Chilling Injury

Control MJ-Treated

Control MJ-Treated

Control MJ-Treated

Control MJ-Treated

Control MJ-Treated

Control MJ-Treated

Control MJ-Treated

0

20

40

60

80

100

120

2 4 6 8 10 12 14

Days

Dec

ay (%

)controlAITCMJAlcTTO

Now let me think…..What could be the mechanisms through which MJ works to exert its effects?

Antioxidant Activity (ORAC)

Treatment

Control

38ºC

MeJA

MeSA

26S rRNA

Days of storage at 5oC0 1 3 7 14 21 28

Accumulation of HSP 17.6 in Different Pretreated Accumulation of HSP 17.6 in Different Pretreated Tomato Fruit During Chilling TemperatureTomato Fruit During Chilling Temperature StorageStorage

Treatment

Control

38ºC

MeJA

MeSA

Days of storage at 5oC0 1 3 7 14 21 28

HSP 70HSP 70--1 (Cytosol) transcripts in different pretreated 1 (Cytosol) transcripts in different pretreated tomato fruit during chilling temperature storagetomato fruit during chilling temperature storage

Treatment

Control

38ºC

MeJA

MeSA

26S rRNA

Days of storage at 5oC

0 1 3 7 14 21 28

PRPR--2B transcripts in different pretreated 2B transcripts in different pretreated tomato fruit during chilling temperature tomato fruit during chilling temperature

storagestorage

Enhanced Expression of 1.5-kb and 3.5-kb AOX Transcripts by 10-4M MeJA in

Cold-Stored Peppers

3.5 kb

1.5 kb

18S

Time (days) 0 1 2 6 14 17 19 1 2 6 14 17 19 1 2 6 14 17 19Time (days) 0 1 2 6 14 17 19 1 2 6 14 17 19 1 2 6 14 17 19Air 10-5M MeJA 10-4M MeJATreatment Air 10-5M MeJA 10-4M MeJATreatment

(°C) 25 25257 200 200 200°C) 25 25257 200 200 200

Methyl Jasmonate & Methyl Salicylate

1. Are they safe to use?

2. Are they toxic?

3. Are they carcinogenic?

FDA (Food and Drug Administration)

EAFUS (Everything Added to Food in the US)

GRAS (Generally Recognized As Safe)

Document Document

___________________Type_____Number_______

Methyl Jasmonate ASP* 0980

Methyl Salicylate ASP 1600

_________________________________________

*Fully up-to-date toxicology information has been sought.

Conclusions• Browning and decay are two of the most serious

problems in fresh-cut• Browning can be prevented by treatment with

naturally occurring inhibitors of PPO• Fresh-cut products are not immune from chilling

injury, except that the injury is expressed in different forms

• Decay induced by chilling injury can be reduced by UV-C irradiation or by GRAS treatment

• Methyl jasmonate appears to reduce decay and chilling injury through enhancing defensive gene expression and increasing antioxidant activity

Conclusions (Continue)•• Increase Increase phenolicphenolic acid and acid and anthocyaninanthocyanin in lettucein lettuce

•• Increase biosynthesis of Increase biosynthesis of flavonolsflavonols (Quercetin(Quercetin--33--rutinoside, Quercetinrutinoside, Quercetin--33--diglucoside and diglucoside and QuercetinQuercetin--33--glucosylrutinoside) in potatoglucosylrutinoside) in potato

•• Decrease ascorbic acid and increase Decrease ascorbic acid and increase dehydrodehydro--ascorbic acid in pineapple, kiwi, cantaloupe and ascorbic acid in pineapple, kiwi, cantaloupe and mangomango

•• Decrease total Decrease total carotenoidscarotenoids in cantaloupe, in cantaloupe, mango, and pineapplemango, and pineapple

•• Effect on Effect on phytonutrientsphytonutrients is variable because of is variable because of wounding stress and oxidation.wounding stress and oxidation.

Keep improving…………...To maintain better quality of fresh-cut products.

To develop better methods for reducing

browning, decay, and chilling injury.

Keep improving…………...