March, 1996 September, 2004 - Fresh-cut 2015fresh-cut2015.ucdavis.edu/files/220790.pdf9/22/2015 1 PreharvestFactors and Fresh‐cut Quality of Leafy Vegetables Mabel Gil Research Group

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1

Preharvest Factors and Fresh‐cut Quality of Leafy Vegetables

Mabel Gil

Research Group on Quality, Safety and Bioactivity of Fruits and VegetablesCEBAS‐ CSIC, Murcia Spain

September, 2004March, 1996

1. Fresh appearance

2. No discoloration,

3. No decay,

4. Crisp texture,

5. Good flavour (aroma and taste)

Quality characteristics of leafy greens

Main causes of quality loss

1. Browning

2. Off‐ flavours

3. Texture loss

3. Agricultural practices

2. Environmental conditions

1. Genotypes

Pre‐harvest factors that affect quality of leafy greens

4. Maturity at harvest

5. Harvest time

Yield (high plant density, low core lenght, solid midrib),

Visual appearance, flavor,

Resistant to internal defects (tipburn and pinkrib),

Health promoting constituents

1. Genotype

Criteria for the selection

mg

100

g-1 F

W

0

50

100

150

200

250

Monet

Batavia verde

Romana verde

Romana roja

Lollo rosso BerroMizu

na

Rúcula salvaje

Rúcula cultiv

ada

Flavones derv.Cinnamic acid derv. Antocyanin derv.

LSD52 Total polyphenols

0

Monet

Green Batavia

Green Romaine

Red Romaine

Lollo rosso

Watercre

ssMizu

na

Wild rocket

Salad rocket

Individual and total polyphenol content of baby leaves

1. Genotype: Selection based on health promoting constituents

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2

Yield (high plant density, low core elnght, solid midrib),

Visual appearance, flavor,

Resistant to internal defects (tipburn and pinkrib),

Health promoting constituents

1. Genotype

Criteria for the selection

Selection of cultivars with lower response for cutting

Conditioning

Harvest

Transport to the CEBAS

Raw material cooling

1. Maturity index2. Removal of external leaves

Washing

3. Cutting

Centrifugation

Packaging

Storage

Evaluation and analysis

1. Genotype: Selection based on lower response to cutting

Passive MAPActive MAP

Cultivars

1 2 3 4 5 6 7 8 9 10 11 12

She

lf-L

ife

0

2

4

6

8

10

12

14

PassiveActive

1. Genotype: Selection based on browning potential

Shelf life of 12 cultivars of fresh‐cut Romaine lettuce stored in passive and

active MAP for 3 days at 4ºC plus the rest of storage at 7ºCCut edge browning of fresh‐cut Romaine lettuce cultivars stored

for 11 days at 7ºC

1 = absence, 3 = moderate and 5 = severe


CULTIVAR

1 2 3 4 5 6 71

2

3

4

5

+ 24 h in air

Cultivar

1 2 3 4 5 6 71

2

3

4

5

Active MAP

CULTIVAR

Quality attributes

1 4

Vitamin C - +

Phenolic content + -

PAL + -

POD + -

PPO + -

% PPO activation + -

Respiration rate + -

Browning in air + -

Browning in MAP - -

Off-flavours in MAP + -

Harvest dates:

‐ December

‐ January

‐ April

Results:

Cultivar 1 vs cv 4: higher susceptibility to

browning, lower vitamin C, higher

phenolic content and higher enzymatic

activities of browning related enzymes

(PPO and POD)

Tissues studied:

‐ Photosynthetic + midrib

‐Midrib

Differences between two Romaine cultivars


UPLC‐MS‐QTOF (Quadrupole + Time of

flight): Non‐targeted metabolomics.

Exact molecular weight and chemical

formula. High sensitivity. Authentic

standards for identification

Agilent QTOF 6550 Agilent QQQ 6460

Biomarkers of enzymatic browning (AGL2013‐48529‐R)

Plant metabolites including phenolic compounds and other primary and secondary metabolites evaluated using a metabolomic approach

UPLC‐MS‐QQQ (Triple Quadrupole):

Targeted metabolomics. High

sensitivity. Authentic standards

for quantitation


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3

UnbrownedBrowned

Browned

Unbrowned



Selection of specific groups of metabolites by clustering and principal component analysis

The untargeted metabolomic study was able to differentiate three groups ofmetabolites that were able to explain differences in the browning process

Barracuda Greenforest

Compound0 Days of storage

5 Days of storage

0 Days of storage

5 Days of storage Class

PS(20:5(5Z,8Z,11Z,14Z,17Z)/0:0) Phospholipids

LysoPE(15:0/0:0) Phospholipids

PE(18:0/0:0) Phospholipids

LysoPE(0:0/18:4(6Z,9Z,12Z,15Z)) Phospholipids

PS(18:3(6Z,9Z,12Z)/0:0) Phospholipids

PI(18:3(6Z,9Z,12Z)/0:0) Phospholipids

LysoPE(0:0/18:3(9Z,12Z,15Z)) Phospholipids

PS(18:2(9Z,12Z)/0:0) Phospholipids

Camila tesela

Compound0 days of storage

5 days of storage

0 days of storage

6 days of storage Class

PIP(16:1(9Z)/18:0) Phospholipids

PI(18:2(9Z,12Z)/0:0) Phospholipids

PI(18:3(6Z,9Z,12Z)/0:0) Phospholipids

LysoPE(0:0/20:2(11Z,14Z)) Phospholipids

PE(19:0/0:0) Phospholipids

LysoPE(0:0/20:2(11Z,14Z)) Phospholipids



LysoPE(18:3(6Z,9Z,12Z)/0:0) Phospholipids



LPA(18:2(9Z,12Z)/0:0) Phospholipids

PA(18:3(9Z,12Z,15Z)/0:0) Phospholipids



Phospholipids, Fatty acids and Phenylpropanoids

Days of storage0 2 4 6 8 10 12 14 16

kP

a

0

2

4

6

8

10

12

14

16

4ºC 7ºC

Days of storage

O2

CO2

0 2 4 6 8 10 12 14 16

Off

-od

ours

1

2

3

4

5Var 5Var 6Var 7Var 8Var 9Var 10

Gas composition (left) and off‐flavors (right) of fresh‐cut Iceberg cultivars

stored in Active MAP for 3 days at 4ºC + 13 days at 7ºC

1. Genotype: Selection based on low off‐flavor potential

septum

juice

fiber

Incubation15 min at 35 ºC

Time (min.)

0 2 4 6 8 10 12 14

0

1e+6

2e+6

3e+6

4e+6

5e+6

Ace

tald

eh

yde

Dim

eth

yl s

ulfi

de

Eth

yl a

ceta

te

Eth

an

ol

Inte

rna

l Sta

nd

ard

He

xan

al

Tra

ns-

2-h

exe

na

l

1-h

exa

no

lC

is-3

-he

xen

-1-o

lT

ran

s-2

-he

xen

-1-o

l

Tra

ns-

cary

op

hyl

len

e

2-m

eth

yl b

uta

na

l3

-me

thyl

bu

tana

l

Pe

nta

na

l

Lim

on

ene

Iso

am

yl a

lco

ho

l

Sulfides Aldehydes Alcohols Terpenes

Analysis of volatiles by GC‐MS Solid Phase Micro

Extraction (SPME)


Day 0

1. Acetaldehyde2. Dimethyl sulfide3. 2‐Methyl propanal4. Ethyl acetate5. 2‐Methyl butanal6. 3‐Methyl butanal7. Ethanol8. α‐ Pinene9. 3‐Methyl‐pentanal10. Toluene11. Butanoic acid 2‐methyl ethyl ester12. Butanoic acid 3‐methyl ethyl ester13. Hexanal14. 1‐Undecane15. Heptanal16. Limonene17. Trans‐2‐hexenal18. Styrene19. 1‐hexanol20. 2‐ethyl‐1,6‐dioxaspiro [4,4]nonane

21. 2‐ethyl‐1,6‐dioxaspiro [4,4]nonane22. 3‐Hexen‐1‐ol23. 2‐nonanone24. 2‐Hexen‐1‐ol25. 2,4‐Hexadienal26. 2,4‐Hexadienal27. 2‐Methoxy‐3‐(1‐methylethyl)‐pyrazine28. 1‐Octen‐3‐ol29. Acetic acid30. 2‐Ethyl‐1‐hexanol31. 2‐Methoxy‐2‐(1‐methylpropyl)‐pyrazine32. 2‐Methoxy‐2‐(2‐methylpropyl)‐pyrazine33. 2‐Nonenal34. 1S‐(‐)Camphor35. Benzaldehyde36. β‐Elemene37. 2,6‐Nonadienal38. Caryophyllene39. Benzeneacetaldehyde40. 2,4‐nonadienal41. 2,4‐nonadienal42. Siloxanes derivatives

1. Genotype: Selection based on low off‐flavor potentialDay 0

Day 13, Damaged tissue

Day 13, Fermented tissue

0 5 10 15 20

Abundan

ce

0

5e+6

1e+7

2e+7

2e+7

0 5 10 15 20

Abundan

ce

0

5e+6

1e+7

2e+7

2e+7

123

5

67 8

9

11

14

15

21

10

13

20

242516 1817

12

1 2

5

67

8

9 10

12

1415 22

11 1619

3

3

0 5 10 15 20

Abundan

ce

0

5e+6

1e+7

2e+7

2e+7

12 3 4

56

7

8

9 10

11

121314

15161718

20

21

22 2423

Day 0

Time

0 5 10 15 20

Abu

ndan

ce

0

5e+6

1e+7

2e+7

2e+7

1

2

5

6

7

IS

13 17

22

2737

19

24

33

4139

303231 38

439 15 23 35

4011

122914 2021

2526 28

Synthetic

Aspirin

Honeydew

melon

Strawberry

Rawalm

ond

Sea, fishy

Candy

Aspirin

Mushroom

Bitter, burny

Good, intense

Mowngrass

Familiar

Red

pep

per, intense

Sweetmelon

Sweaty, p

ungent

Fruity, candy

Cheesy

Acid, m

ild

Rotten

fish

Leather

Combination of gas chromatography‐coupled olfactometry techniques (GC‐O) and gas chromatography–mass spectrometry (GC–MS)

GC‐O AROMAGRAM

GC‐MS CHROMATOGRAM


Biomarkers of gaseous and volatile compounds (AGL2013‐48529‐R)

9/22/2015

4

Selection of cultivars is critical because of the strong influence in the

“freshness” of the fresh‐cut product

Advantages

Consistency of the stability of the shelf life

Consistency of the rawmaterial

Consistency of the quality of fresh‐cut product

1. Genotype selection

Conclusions

1. Genotype selection

Breeding program for lettuce

1. Genotype selection 1. Genotype selection

Other factors such as environmental and cultural practices influence

shelf life

Storage conditions influence shelf life. Experimental design: Active

MAP (0.5% O2 + 8‐10% CO2) + 24 h in air

Results must be confirmed in different seasons and years

Seed companies must provide the selected cultivars through several

years (confidential agreement)

Growers must use recommended cultural practices for cultivation

1. Genotype selection: Disadvantages



1. Genotypes



5. Harvest time

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Influence cultivation in different production areas and growing cyclesVariety 52 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51

Cervantes X X X X X X X X X X X X X X X X X X X X X X X X

Chiquina X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X

Cuore X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X

Cuore PM23 X X X X X X X X X X X X X X X X

Spring Summer FallWinter

2. Environmental conditions: Temperature, RH, light and rainfall

Fresh‐cut Romaine lettuce cultivars stored for 11 d at 7ºC in Active MAP + 24h 7ºC after opening the bags

Cut edge bro

wning

Average temperature during cultivation

Eth

anol c

ontent (ppm)

Average temperature during cultivation

Influence diseases and disorders of lettuces

Frost damage Excess of water Pinkrib TipburnBacterial soft rot


Appearance, location and evolution of spots and alterations observed in lettuce leaves

(Blancard et al., 2005)

Influence differences in the specifications of rawmaterial

‐ Maturity indices: size, weight, compactness


Fresh weight vs harvest week of baby leaf red lettuces

Red Batavia (B1) Red Batavia (B2) Red oak leaf (R)

Fall/Winter: 50 mmSpring/Summer:70 mm

Specifications of raw material


Phenolic compounds vs harvest week vs harvest week of baby leaf red lettuces

Harvest week

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Fla

vono

ids

(mg

100

g-1dw

)

0

20

40

60

80

100

120

140

Harvest week

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Phe

noli

c ac

ids

(mg

100

g-1dw

)

0

10

20

30

40

50

B1 Cy-3GML-7GcQ-3Gc+Q-3GQ-3GM

5-CQACMAdCTA

B1

14050

Cy‐3MG: cyanidin‐3‐O‐(6”‐O‐malonyl)‐glucoside5‐CQA: 5‐caffeoylquinic acidCMA: caffeoylmalic aciddCTA: dicaffeoyltartaric acidL‐7Gc: luteolin‐3‐O‐glucuronideQ‐3Gc: quercetin‐3‐O‐glucuronideQ‐3G: quercentin‐3‐O‐glucosideQ‐3MG: quercetin‐3‐O‐(6”‐O‐malonyl)‐glucoside

Red Batavia (B1)

Radiation and temperature showed positive correlations with the content of phenolic acids and flavonoids that increased as the season progressed


Respiration rate of fresh‐cut Iceberg lettuce harvested in different months stored for 9 d at 7 ºC and 0.5% O2

b

bb

a

Harvest month

Novem

ber

Janu

ary

Febru

ary

May

June

mL

O2 k

g-1 h

-1

0

1

2

3

4

5

b


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6

Greenhouse vs field production

Soilless system in greenhouse: lack of lettuce heart and bolting in the case of butterheadand the lack of color in the case of red‐leafed genotypes, as well as the presence of

tipburn in all genotypes.

2. Environmental conditions: Temperature and light intensity

• Protected culture system: increases yield, allows off‐season production,

controls abiotic factors and facilitates pest management.

• Cultivation in open field: more resistant crops because of the adverse

weather conditions and long growing cycle.

Conclusions




1. Genotypes



5. Harvest time Control

Urban D

1

Urban D

2

Sewage 2

D1

Sewag

e 2 D

2

Yie

ld (

g m

-2)

0

200

400

600

800

1000

% W

ater

Con

ten

t

75

80

85

90YieldWater content

c c c

b

a

x

xy

xy

y

z

Urban(45 and 135 T/ha)

Control

Sewage(45 and 135 T/ha)

3. Agricultural practices: Fertilizers

Organic soil amendments

Control

Urban D

1

Urban D

2

Sewage 2

D1

Sewage 2

D2

Ph

enol

ic c

onte

nt

(mg

100

g-1 f

.w.)

0

75

150

225

300

375

a

b

c bc

d

Glu

cosi

nol

ates

(m

g 10

0g-1

)

0

30

60

90

120

150

180

a

bb

b

b

Organic soil amendments

3. Agricultural practices: Fertilizers

Irrigation regime= Irrigation treatment + Rainfall – Crop evapotranspiration (Etc)Harvest date

Mar

ch '0

9

Novem

ber '0

9

Mar

ch '1

0

October

'10

Febru

ary

'11

May

'11

Wa

ter

su

pp

lied

(m

m)

0

100

200

300

400R4

R3

R2

R1

T1: ControlT2:FC ‐50% T3: FC ‐25% T4: FC +25 %T5: FC +50 %

Deficit

Excess

2009

2010

2011

MarchNovemberMarch October February May

• Crop: Romaine and iceberg lettuce

• Total cultivated area: 1080 m2

• Number of treatments: 5

• Number of harvest: 6

3. Agricultural practices: Irrigation

9/22/2015

7

Visual quality of fresh‐cut Iceberg lettuce stored during 13 days in MAP (3 d at 4 ◦C and 7 ◦C for the rest of the storage) as affected by different irrigation regimes

0 8 10 13

Vis

ual

qu

alit

y

1

3

5

7

9

Days of storage

LSDregime= 0.6

LSDstorage= 0.3

R1 () (0‐100 mm)

R2 () (101‐200 mm)

R3 () (201‐300 mm)

R4 () (301‐400 mm)


Low irrigation doses are recommended for quality and economic reasons

0 1 2 3 40

2

4

6

8

10

12

PP

O (

µM

min

-1)LSDstorage= 2.4

LSDregime= 2.0B

Days of storage

0 1 2 3 4

Cu

t ed

ge

bro

wn

ing

1

2

3

4

5

Days of storage

A

LSDregime= 0.9

LSDstorage= 0.6

Cut edge browning (left) and PPO (right) of fresh‐cut Iceberg lettuce stored in air 7 ◦C as affected by different irrigation regimes

R1 () (0‐100 mm)

R2 () (101‐200 mm)

R3 () (201‐300 mm)

R4 () (301‐400 mm)


0

100

200

300

400

SoilSoilless

Ph

enol

ic c

omp

oun

ds

(mg

100

g-1

f.w

.)

a

b

Lollo ro

sso

Butterh

ead

Red oak lea

f

ns

ns

Caffeic acid derivativesFlavonolsAnthocyanins

Content of phenolic compounds in different lettuce types

3. Agricultural practices: Soil and soilless systems

Medium HighLow Medium HighLow Medium HighLow

Lollo Rosso

Fre

sh

we

igh

t (g

)

0

100

200

300

400

500 Red oak leaf Butterhead

0

100

200

300

400

500

Fre

sh

wei

gh

t (g

)

SummerWinter

Macroanions (NO3‐) and macrocations (K+, Ca2+ and NH4

+)

Genotype and season strong influence on quality and shelf

life of fresh‐cut product

3. Agricultural practices: Nutrient solutions

Lettuces cultivated in soilless under different salinity concentrations (mM NaCl)

Clarkson et al. (2003) observed that lettuces exposed to an stress increased the plasticity which conferred higher acceptability and shelf life to the product.

Ct=0 S1=50 S2=100 S3= 150

10 cm

Elasticity (reversible extension) and plasticity (irreversible extension)

Treatment

Ct S1 S2 S3

Ela

sti

cit

y (%

)

0

1

2

3

4

5

aa

b

a

3. Agricultural practices: Salinity

Higher procesability if there is a combination between small cells with a high solute concentration and strong cellular walls

(Clarkson et al. 2003; Zhang et al., 2007; Wagstaff et al., 2010).

Image captured by the optical microscope (A) and the corresponding

cellular vision in the inner part of the area studied (B)

Analysis of the internal anatomy of the tissue


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8

Ct=0 S1=50 S2=100 S3= 150

10 cm

Analysis of the internal anatomy of the tissue


ue

le

pp

spie

100µm

ue

pp

spie

le100µm

ue

le

sp

ie

pp

100µm

ue

sp

le

ie

pp

100µm

Ct (control) S1 (50 mMNaCl) S2 (100 mMNaCl) S3 (150 mMNaCl)

Ue, upper epidermis; le, lower epidermis; pp, palisade parenchyma; sp, spongy parenchyma; ie, intercellular spaces


Ct=0 S1=50 S2=100 S3= 150

10 cm

Histology: Analysis of the internal anatomy of the tissue


Treatments

Ct S1 S2 S3

Are

a o

f e

pid

erm

al c

ells

(µ

m2)

0

500

1000

1500

2000

2500

Treatments

Ct S1 S2 S3

Are

a o

f p

are

nc

hym

a c

ells

(µ

m2)

0

500

1000

1500

2000

2500

ns

a

b b b

Treatments

Ct S1 S2 S3

Ep

ide

rmis

(%

of

tota

l are

a)

0

20

40

60

80

Treatments

Ct S1 S2 S3

Par

ench

yma

(% o

f to

tal

are

a)

0

20

40

60

80

Treatments

Ct S1 S2 S3

Inte

rcel

ula

r s

pa

ces

(% o

f to

tal a

rea

)

0

20

40

60

80

ns

abb b

aab ab

b


3. Agricultural practices: Drought stress

Content of phenolic compounds with mild and

severe deficit irrigation (DI)

Purple

Days of storage

0 5 7

Phe

nol

ics

com

pou

nds

(mg

/ 100

g f.

w.)

0

1000

2000

3000Control25% DI50% DI

Green

Days of storage

0 5 7

Genovese

Days of storage

0 5 70

1000

2000

3000

Ph

enol

ics

com

poun

ds (

mg

/ 100

g f.

w.)

Phenolic

compounds(m

g/100 g FW)

Phenolic

compounds(m

g/100 g FW

)3. Agricultural practices

• Optimization and control of agricultural practices are of paramount

importance, particularly IRRIGATION, to ensure the quality leafy greens.

• The combination of adequate production systems and suitable cultivars is

considered essential to ensure the shelf life of leafy greens.

Conclusions



1. Genotypes



5. Harvest time0 2 4 6 8 10 12

kPa

0

2

4

6

8

10

12

14

16

O2

CO2

Days of storage

Immature

Commercial

Over‐mature


Influence of maturity stage on quality of fresh‐cut Iceberg lettuce

Headspace gas composition of fresh‐cut Iceberg

lettuce at different maturity stages

Kader and Cantwell, 2010 with permission

9/22/2015

9

0 9 13

Ace

tald

ehy

de (

µm

ol 1

00 g

-1fw

)

2

4

6

8

10

12

0 9 13

Days of storage

aa

b

a

bb

a

aa

1000

2000

3000

4000

5000

6000

a

bb

a

b

Eta

nol

(µ

L kg

-1fw

)

c

A

B

Immature

Commercial

Over‐mature

Days of storage


Kader and Cantwell, 2010 with permission

Ethanol (A) and acetaldehyde (B) of fresh‐cut Iceberg lettuce at different maturity

stages

MS 2 > 40 and ≤ 60 mm

MS 3> 60 and ≤ 80 mm

MS 4 > 80 mm Days of storage

0 2 4 6 8 10 12 14

Vis

ual Q

uali

ty (

Scor

e)

1

2

3

4

5

6

7

8

9

MS 2MS 3MS 4


Influence of maturity stage on quality of fresh‐cut Romaine lettuce

Baby Multi Whole

Density of planting(plants/m2)

300 30 7

Cultivation (Days) 66 95 130

Baby Multi Whole heads


0

200

400

600

800

1000

1200

1400

0

200

400

600

800

1000

1200

1400

Con

ten

ido

fen

ólic

o (m

g·10

0 g-1

p.f

.)

Con

ten

ido

fen

ólic

o (m

g·10

0 g-1

p.f

.)

Hoja verde Hoja roja Lollo rosso

Derivados de ácidos cafeicos Flavonoides Antocianos

Baby Multi Cabezas Baby MultiBaby Multi Cabezas CabezasBaby Multi Whole Baby Multi Whole Baby Multi Whole

Cafeic acid derivativesFlavonoidsAnthocyanins

Green Leaf Red Leaf Lollo Rosso

Content of polyphenols(m

g 100 g

‐1FW

) Content o

f polyp

henols(m

g 100 g ‐1

FW)


Content of individual and total polyphenols


Influence of maturity stage on quality of fresh‐cut Iceberg lettuce

Days of storage

-2 0 2 4 6 8 10 12 14 16

0

Days of storage

-2 0 2 4 6 8 10 12 14 16

0

Days of storage

-2 0 2 4 6 8 10 12 14 16

Unwashed

Wash

ed

Unwashed

Wash

ed

Unwashed

Wash

ed

kPa

Lactic acid bacteria

0

1

2

3

4

5

6

7

8

Lac

tic

acid

bac

teri

a

0

1

2

3

4

5

6

7

8

Red LeafGreen Leaf Lollo RossoBaby-leafMulti-leafWhole-head



1. Genotypes



5. Harvest time

9/22/2015

10

Harvest Processing Storage

8:00 h

H1

24 h

13:00 h

H2

24 h

17:30 h

H3

24 h

3d 40C+ 6d 70C

5. Harvest time: Time of the day for harvest

Growing cycle: 54 dSun radiation: 7 h/dayTª : 10 0CRain: 0.1 mm

Growing cycle: 36 d Sun radiation: 9 h/dayTª : 13 0CRain: 1.1 mm

January

April

Leaf water content and environmental Vapor Pressure Deficit (VPD)

1:004:00

7:0010:00

13:0016:00

19:0022:00

H1

H2

H3

0

0.0

0.3

0.5

0.8

1.0

1.3

1.5

020

40

60

80H1 H2 H3

Wat

er c

onte

nt

(%)

At harvest

020

40

60

80H1 H2 H3

Wat

er c

onte

nt (

%)

At harvest

Winter Spring

0

0.0

0.3

0.5

0.8

1.0

1.3

1.5

22:001:00

4:007:00

10:0013:00

16:0019:00

H1

H2 H3

VP

D (

KP

a)

VP

D (

KP

a)

(VPD: Vapor Pressure Deficit)


Dehydration of the leaves in the middle ofthe day but it recovers in the afternoon.

Dehydration as the day progresses.

Respiration rate of minimally processed baby spinach cultivated in spring, harvested at different times and stored for 9 d at 7 ºC

H1: 8:00h

H2: 13:00h

H3: 17:30h

0 2 in

take

(m

l Kg-1

h-1

)

0

5

10

15

20

25

H1 H2 H3

5. Harvest time: Time of the day for harvestVisual quality of minimally processed baby spinach harvested at different times

and stored for 3 d at 4 ºC and 6 d at 4 ºC

Vis

ual

qu

ality

1

2

3

4

5

6

7

8

9

0 days

of storage9 days

of storage

0 days

of storage9 days

of storage

Vis

ual

qu

ality

1

2

3

4

5

6

7

8

9

Winter Spring

H1 H2 H3

H1: 8:00hH2: 13:00hH3: 17:30h


9 5 18 7 6 4 3 2

InedibleInedibleLimit of marketabilityLimit of marketabilityExcellentExcellent

• In winter, the differences observed among harvest times were reduced after

processing during storage, while in spring these differences remained.

• Baby spinach could be harvested at any time of the day in winter and early morning in

spring.

• Baby spinach harvested early in the morning had a higher water content, firm

texture, lower respiration rate and better visual quality.

Conclusions


A greater understanding of the mechanisms, including the metabolites

involved in browning, off‐odor development and texture loss will led to the

identification of the key preharvest factors for each species or cultivar.


Future steps

9/22/2015

11

1 : Genotypes

2 : Environmental conditions

Marin, A., Ferreres, F. Barberá, G.G., Gil, M.I.2015. Weather variability influences color and phenolic content of pigmented baby leaflettuces throughout the season. J. Agric. Food Chem., 63, 1673‐1681.

References: Preharvest Factors and Fresh‐cut Quality of Leafy Vegetables

Martínez‐Sánchez, A., Gil‐Izquierdo, A., Gil, M.I., Ferreres, F. 2008. A comparative study of flavonoid compounds, vitamin C and

antioxidant properties of baby leaf Brassicaceae species. J. Agric. Food Chem., 56, 2330‐2340.

Tudela, J.A., Marín, A., Martínez‐Sánchez, A., Luna, M.C., Gil, M.I. 2013. Preharvest and postharvest factors related to off‐odours offresh‐cut iceberg lettuce. Postharvest Biol. Technol., 75, 75‐85.

3 : Agricultural practices

Selma, M.V., Luna, C., Martínez‐Sánchez, A., Tudela, J.A., Beltrán, D., Baixauli, C., Gil, M.I. 2012. Sensory quality, bioactive constituentsand microbiological quality of green and red fresh‐cut lettuces (Lactuca sativa L.) are influenced by soil and soilless agriculturalproduction systems. Postharvest Biol. Technol., 63, 16‐24

Luna, C., Tudela, J.A., Martínez‐Sánchez, A., Allende, A., Marín, A., Gil, M.I. 2012. Long term deficit and excess of irrigation influencesquality and browning related enzymes and phenolic metabolism of fresh‐cut iceberg lettuce (Lactuca sativa L.). Postharvest Biol.Technol., 73, 37‐45.

3 : Agricultural practices

Luna, C., Tudela, J.A., Martínez‐Sánchez, A., Allende, A., Gil, M.I. 2013. Optimizing water management to control respiration rate andreduce browning and microbial load of fresh‐cut romaine lettuce, Postharvest Biol. Technol., 80, 9–17.

Luna, M.C., Martínez‐Sánchez, A., Selma, M.V., Tudela, J.A., Baixaulib, C., Gil, M.I. 2013. Influence of nutrient solutions in open fieldsoilless system on the quality characteristics and shelf life of fresh‐cut red and green lettuces (Lactuca sativa L.) in differentseasons, J. Sci. Food Agric., 93, 415‐421.

Gil, M.I., Tudela, J.A., Luna, M.C. 2013. Water management and its effect on the postharvest quality of fresh‐cut vegetables. StewardPostharvest Review, September 1:2

Garrido, Y., Tudela, J.A. Marín, A., Mestre, T., Martínez, V., Gil, M.I. 2014. Physiological, phytochemical and structural changes of multi‐leaf lettuce caused by salt stress. J. Sci. Food Agric., 94, 1592‐1599

Bekhradi, F., Luna, M.C., Delshad, M., Jordan, M.J., Sotomayor, J.A., Martínez‐Conesa, C., Gil, M.I. 2015. Effect of deficit irrigation on the postharvest quality of different genotypes of basil including purple and green Iranian cultivars and a Genovese variety. Postharvest Biol. Technol., 100, 127‐135.

Bekhradi, F., Delshad, M., Marín, A., Luna, M.C., Garrido, Y., Kashi, A., Babalar, M., Gil, M.I. 2015. Salt stress on physiological andpostharvest quality characteristics of different Iranian genotypes of basil. Horticulture Environment and Biotechnology, in press.


4 : Maturity at harvest

Gil, M.I., Tudela, J.A., Martínez‐Sánchez, A., Luna, M.C. 2012. Harvest maturity indicators of leafy vegetables. Steward PostharvestReview, June 1:2

5 : Harvest time and postha<rvest handling

Medina, M.S., Tudela, J.A., Mar<<<<<<<ín, A., Allende, A., Gil, M.I. 2012. Short postharvest storage under low relative humidityimproves quality and shelf life of minimally processed baby spinach (Spinacia oleracea L.). Postharvest Biol. Technol., 67, 1‐9.

Martínez‐Sánchez, A., Luna, C., Selma, M.V., Tudela, J.A., Abad, J., Gil, M.I. 2012. Baby‐leaf and multi‐leaf of green and red lettuces aresuitable raw materials for the fresh‐cut industry. Postharvest Biol. Technol., 63, 1‐10.

Garrido, Y., Tudela, J.A., Gil, M.I. 2015. Time of day for harvest and delay to processing affect the quality of minimally processed babyspinach. Postharvest Biol. Technol., 110, 9‐17.



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Documents

March, 1996 September, 2004 - Fresh-cut 2015fresh-cut2015.ucdavis.edu/files/220790.pdf9/22/2015 1 PreharvestFactors and Fresh‐cut Quality of Leafy Vegetables Mabel Gil Research Group