Upload
chu-bagunu
View
222
Download
0
Embed Size (px)
Citation preview
7/29/2019 Postharvest Handling Update Cool Season Vegetables
1/30
Postharvest Handling Update
Cool Season Vegetables
Marita Cantwell, UC Davis
[email protected]://postharvest.ucdavis.edu
UCCE Vegetable Pest Management and Postharvest Issues
Santa Maria, June 9, 2010
7/29/2019 Postharvest Handling Update Cool Season Vegetables
2/30
http://postharvest.ucdavis.edu
Produce Facts
Harvest indices Quality indices
Temperature and RH
Freezing point/damage
Respiration rates
Ethylene production
Effects of ethylene Effects of modified
atmospheres
Physiological disorders
Postharvest diseases
Mechanical injury
PHOTOS
140FruitsVegetablesFlowers
7/29/2019 Postharvest Handling Update Cool Season Vegetables
3/30
Causes of Quality & Postharvest Losses
Leafy VegetablesLettuces
Spinach
CabbageChard
Broccoli
Celery
HerbsEndives
Asparagus
Green Onions
Water loss
Mechanical damage
Loss of chlorophyll andother nutrients
Respiration rates
Microbial growth
Sensitivity to ethylene
7/29/2019 Postharvest Handling Update Cool Season Vegetables
4/30
Fresh Produce
Deterioration
Metabolic changes:
respiration, ethylene, texture, aroma, etc.
Growth and development
Transpiration
Mechanical injury Physiological disorders
Decay; microbial growth
Temperature
Affects All
Causes ofDeterioration
7/29/2019 Postharvest Handling Update Cool Season Vegetables
5/30
Postharvest Handling Update
Cool Season Vegetables Broccoli
Iced to iceless product; firmness and water loss
Specialty Brassicas Compare postharvest performance to broccoli
Fresh-cut and modified atmospheres Response of broccoli and sugar snap peas
Cauliflower --needs postharvest work
Cabbage Quality and Temperature
Lettuce Varieties Fresh-cut performance
7/29/2019 Postharvest Handling Update Cool Season Vegetables
6/30
Storage temperature
D
ays
(toinitiate
yellowing)
0
5
10
15
20
25
30
35 Broccoli Shelf-life & Temperature
032
2.536
541
7.545
1050
12.555
1559
20C68F
cv. Legacy
Fresh appearance
Green florets
Tender stem
No discoloration
No breakage
No decay
No off-odors
7/29/2019 Postharvest Handling Update Cool Season Vegetables
7/30
mg/100gFW
0
5
10
15
20
25
mg/100gFW
0
1
2
3
4
Days
0 5 10 15 20 25
mg
/100gFW
0
5
1015
20
25
30
35
40
Days
0 5 10 15 20 25
mg
/100gFW
0
5
10
15
20
25
Chlorophyll Carotenoids
Ascorbic Acid Sugars
0C (32F)10C (50F)
20C (68F)
Limit ofSalability
Broccoli Compositional Quality and Storage Temperature
Cantwell, unpublished
7/29/2019 Postharvest Handling Update Cool Season Vegetables
8/30
Days
0 2 4 6 8 10 12 14 16 18
Co
lorscore,
5=d
arkgreen,
1=ye
llow
1
2
3
4
5
Mature Kale Leaves 20C (68F)15C (59F)10C (50F)5C (41F)
Days
0 2 4 6 8 10 12 14 16 18
Immature Kale Leaves
LSD.05
Loss of green color by mature and immature Kale leaves storedat 4 temperatures for up to 18 days.
5 4 3 2 1
7/29/2019 Postharvest Handling Update Cool Season Vegetables
9/30
10C Air 1-MCP, 10C Air 10C C2H4 1-MCP, 10C C2H4
12 days; 8 ppm C2H4;500 ppb 1-MCP
Collards
5C Air 10C Air 10C C2H4
1-MCP=1-methyl-cyclopropene, SmartFresh, AgroFresh
7/29/2019 Postharvest Handling Update Cool Season Vegetables
10/30
Chlorop
hy
ll,mg
/gFW
0.3
0.4
0.5
0.6
0.7
0.8
0C Control 0C 1-MCP
5C Control 5C 1-MCP
10C Control 10C 1-MCP
A. Chlorophyll
LSD.05
Days
0 5 10 15
Sugar,
mg
/gFW
3
4
5
6
7
8B. Sugar
LSD.05
VitaminC,mg/100gFW
40
80
120
160
200
240
280
0C Control 0C 1-MCP
5C Control 5C 1-MCP
10C Control 10C 1-MCP
A. Vitamin C (AA + DHA)
LSD.05
Days
0 5 10 15
Glucoraphinin,mole/gDW
5
6
7
8
9
10
11
12
13
14
15B. Glucoraphinin
LSD.05
Broccoli and Temperature and 1-MCP (no ethylene exposure)
Glucoraphin produces Sulforaphane potent Phase 2 Enzyme Inducer, inhibit cancer
7/29/2019 Postharvest Handling Update Cool Season Vegetables
11/30
Specialty Brassicas Comparative Study
Gai-lan
Choi-sum
Broccoli raab, rapini
Broccolini
Florets Stem Tissue
Component
Initial 5C,
8d
10C
8d
Initial 5C
8d
10C
8d
Total sugars, mg/gFW 5.2 4.5 3.7 17.4 14.4 12.0
Ammonia, mole/100gFW 1.1 1.4 2.3 0.5 1.0 1.1Antioxidant activity
mg Trolox/100g FW
117 100 92 47 43 32
Vitamin C, mg/100g FW 235 176 112 87 86 88
M. Cefola, G. Hong, M. Cantwell, R. Paiva e G. Colelli. 2009
Marketable quality
Compositional qualityResponse to Temperature
Response to atmospheres
Broccoli raab
7/29/2019 Postharvest Handling Update Cool Season Vegetables
12/30
0
200
400
600
800
1000
1200
1400
1600
0C 5C 10C
AMMONIA
INC
REASE
25
27
29
31
33
35
37
39
TOTALGS
ACTIVITY
AMMONIA INCREASE GS TOT
6 days, data of Eghle Catalano, 2007
Changes in ammonia andGS activity in Spinach
Days
0 2 4 6 8 10 12 14 16 18
mg
/gfres
hweig
ht
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
2.5C 36F
5C 41F
7.5C 45F
10C 50F
Ammonia concentration
Changes in ammonia in spinachat 4 temperatures over 18 days
7/29/2019 Postharvest Handling Update Cool Season Vegetables
13/30
mo
le/100g
FW
0
50
100
150
200
250
300
350
400
450A. Ethanol
mo
le/100g
FW
0
10
20
30
40
50
60
70
80
90 B. Acetaldehyde
Days at 5C
0 3 6 9 12 15 18
g/g
FW
0
10
20
30
40
50
60
70
80
Days at 5C
0 3 6 9 12 15 18
g/gFW
45
50
55
60
65
70C. Ammonia D. Sugars
LSD.05
3%O2+7%CO2
3%O2+12%CO23%O2+18%CO210%O2+12%CO2
Air
3%O2+7%CO2
3%O2+12%CO23%O2+18%CO210%O2+12%CO2
Air
Test #2
7/29/2019 Postharvest Handling Update Cool Season Vegetables
14/30
18 days at 5C (41F)
A B C D E3+7 3+12 3+18 10+12 Air
DAMAGING
Air=Best quality
7/29/2019 Postharvest Handling Update Cool Season Vegetables
15/30
Iceless BroccoliTemperature-yellowing
Moisture loss-softening
0C with very high humidity MA: 5-8% O2 + 7-10% CO2
Broccoli Storage Conditions
7/29/2019 Postharvest Handling Update Cool Season Vegetables
16/30
Table 1. Broccoli head firmness and compactness scoring and the relationship to firmness
measurements on texture analyzer. This table based on preliminary 2009 data.
Subjective
score
Description Objective firmness
N compression
force*
5 Heads hard, very tight and firm 65-100N
4 Heads firm, a few outer florets may be loosened 50-80
3 Heads moderately firm, with some florets loosened** 40-60
2 Heads moderately soft, with most florets loosened 25-40
1 Heads soft, with extensive loosening of florets 10-25
*Heads compressed with a flat disc to a depth of 7.5 mm
**A score of 3 is likely the limit of marketability at retail.
7/29/2019 Postharvest Handling Update Cool Season Vegetables
17/30
Days at 7.5C
0 1 2 3 4
%
We
ightloss
0
1
2
3
4
5
6
7
8
Curve 1, y= 1.55x+ 0.34; R2
= 0.98
Curve 2, y= 1.72x+ 0.36; R2
= 0.98
Curve 1 original firmness techniqueCurve 2, modified technique, mark
A. % Weight Loss
Days at 7.5C
0 1 2 3 4 5 6 7
%Firm
nessloss
0
10
20
30
40
50
60
70
80
90
100
Curve 1 original firmness technique
Curve 2, modified technique, mark
B. % Firmness Loss
Minimize delay from harvest to cooling
Use plastic liners to reduce water loss
Keep it cold
7/29/2019 Postharvest Handling Update Cool Season Vegetables
18/30
2.5C (36F) 5C (41F) 7.5C (45F)
14 days air
7/29/2019 Postharvest Handling Update Cool Season Vegetables
19/30
14 days 5C (41F)
5% O2 5% O2 + 7.5% CO2 5% O2 + 15% CO2
7/29/2019 Postharvest Handling Update Cool Season Vegetables
20/30
14d 5C
Quality ProblemsGrayingLoss of fluidOff-odor
Air 1%O2 +15% CO2
7/29/2019 Postharvest Handling Update Cool Season Vegetables
21/30
RESEARCH TO DO
Evaluate the performance of cultivars forquality of fresh market and fresh-cut product
Evaluate the impact of initial postharvesthandling on the shelf-life and quality offresh-cut cauliflower florets.
Evaluate the impact of production conditions(seasonablity, fertilization, irrigation) on thequality and shelf-life of cauliflower florets
Cauliflower Qualitycolor is cream white
freedom from mechanical injury
freedom from decay
overall attractive appearance
no discoloration on cut edges
minimal number of small pieces; good integrity of cut florets
good aroma and odor as fresh or microwaved food
retain high content of sugars and Vitamin C
Days
1 2 3 4 5 6
Resp
ira
tion
(LCO
2/g-h
)
0
20
40
60
80
100
120
140 0C (32F)
5C (41F)
10C (50F)15C (59F)20C (68F)
A. Heads
Days
1 2 3 4 5 6
B. Florets
7/29/2019 Postharvest Handling Update Cool Season Vegetables
22/30
Napa or Chinese cabbage
Black Speck Disorder
7/29/2019 Postharvest Handling Update Cool Season Vegetables
23/30
Cultivar
1 2 3 4 5 6 7 8 9
Blackspec
kindex
0
50
100
150
200
250
Air
Ethylene
Cv #1= T-7402= Yuki3= Spring Flavor4= Southern King
5= New Summer6= Chacha7= China Express8= Blues9= WR-70
Black speckdevelopmenton Napa cabbage
stored in air or in
ethylene is the same.
PAL enzyme
levels similar; 1-MCP does not reduce
black speck.
Cultivars vary
greatly in their
susceptibility toblack speck.
Black speck index = black speck score multiplied by % extension.
Black Speck Disorder on Chinese Cabbage
7/29/2019 Postharvest Handling Update Cool Season Vegetables
24/30
Cabbage Quality and TemperatureCDFA WIC Stores Small Farm Program Project
Shermain Hardesty, Lucia Kaiser, and Advisors
Retail handlinggood to poor conditions
Impact on marketability and nutritional value
conditions to retain 80% original nutrition
Vitamin C, Antioxidant Activity, Carotenoids
Wide range of temperatures (0-29C; 32-84F)
Cabbage performs well over temp rangeshould be
available in all WIC stores
7/29/2019 Postharvest Handling Update Cool Season Vegetables
25/30
Fresh-cut Lettuces
Varieties of Iceberg, Romaine and Crosses
Performance as fresh-cut product
Visual quality score
Discoloration
Decay
Respiration rates
Phenolics and phenolic enzymes (PAL, PPO)
Composition
Number leaves per head
% dry weight Sugars
Chlorophyll and carotenoids
Vitamin C
Ammonia
7/29/2019 Postharvest Handling Update Cool Season Vegetables
26/30
Discoloration Rating Scale for Romaine
13
4 5
2
7/29/2019 Postharvest Handling Update Cool Season Vegetables
27/30
Totalsu
gars(mg/gfwt.)
0
5
10
15
0 days
7 days
HeartInner
Young Midsize Full sizeOuter
Leaf Position
Total sugars
LSD.05
Leaf Position
To
talascorbicac
id(mg
/100g
fwt.)
0
10
20
30
40 0 days
7 days
LSD.05
Vitamin C (Total Ascorbic Acid)
HeartInner
Young Midsize Full sizeOuter
Romaine
lettuce
7/29/2019 Postharvest Handling Update Cool Season Vegetables
28/30
Variety
1 2 3 4 5 6 7 8 9 10 11 12 13
Russe
tSpo
tting
Score
1=none,
9=severe
1
2
3
4
5
6
7
8
1=Sonoma2=Spreckles3=Salinas 5214=Raider5=Salinas 5176=Buena Vista7=Stinger8=Van Sal 2109=Salinas
10=Ace11=Champ12=Salinas 8813=Ridgemark
A. Iceberg Lettuces
Variety
1 2 3 4 5 6 7
B. Romaine Lettuces
1=Paris Island Cos2=Romo3=Red Eye Cos4=Gx8005=Corazon
6=Red Hot Cos7=Nero
Development of Russet Spot Disorder on Iceberg and Romaine Lettuces.Intact heads were stored in 5ppm ethylene at 5C (41F) plus 1 week in air.
Cantwell, UC Davis, unpublished
7/29/2019 Postharvest Handling Update Cool Season Vegetables
29/30
Is Temperature a Quality Issueor a Food Safety Issue?
Prevention of Contamination is most important Time and Temperature are Amplifiers of Risk
Slide from Trevor Suslow, UC Davis
7/29/2019 Postharvest Handling Update Cool Season Vegetables
30/30
1) Harvest at correct maturity
2) Reduce physical handling
3) Protect product from sun
4) Keep packingline simple and
clean; ensure good worker hygiene5) Select, classify, and pack carefully
6) Align cartons, strap pallet
7) Cool as soon as possible
8) Know market and product requirements9) Coordinate efficient & rapid handling
10)Train and compensate workers adequately
10 Basic Postharvest Principles