Harvest & Post Harvest Handing of Blueberries for Fresh & IQF Markets. Charles F. Forney Kentville Research and Development Centre

Harvest & Post Harvest Handing of Blueberries for Fresh & IQF Markets Charles F. Forney Kentville Research and Development Centre

Factors Affecting Fruit Quality and Market Life Fruit Quality Cultural practices/environment Harvest factors Packing and handling Temperature management Storage environment

Fruit Quality Parameters Size Color Bloom Firmness Defects Flavor

IQF Fruit Quality CFIA Grade A fruit Good flavour of well-ripened blueberries Uniform colour Good condition Free from cap stems Free from defects Clusters, Leaves, Stems, Green berries, Extraneous material Good condition-avoid splits Loss of sugars Toughening Increase drip loss upon thawing

Postharvest Quality Loss Mechanical damage Shrivel/water loss Decay Physiological breakdown Loss of flavor

Importance of Initial Fruit Quality Determines fruit marketability potential market life Fruit quality can not be improved postharvest

Shrivel Dehydration Overripe Split Mechanical damage Excess water Decay Insect/bird damage Decay Defects

Genetic Effects - Cultivars Marketable fruit (%) 100 90 80 70 60 50 6 weeks 0 C 3 C 40 Burlington Nelson Elliot Brigitta Jersey Coville Cultivar

Genetic variability Wild fields V. angustifolium Aiton ~95% of wild fields V. myrtilloides Michaux Clonal differences Determine storage potential ~109 different clones/acre V. angustifolium V. myrtilloides

Fertility Cultural Practices/Environment Pollination Field cleanliness Weed control Debris Rainfall Temperature Stress - Biotic - Abiotic

Fruit maturity Harvest Factors Environment Method

Quality Changes during Ripening on the Plant Firmness Declines rapidly during color development Titratable acids Declines during color development and further ripening Soluble solids Increases during color development and further ripening Firmness (g/mm) 700 600 500 400 300 200 100 TA SS SS/TA 0 white 0 3 6 9 Ripeness (days following color turning) 3 2 1 0 14 12 10 15 10 5 0 3 6 9 Ripeness (days following color turning)

Harvest Timing Wild Blueberries Once-over harvest Challenge of determining optimum harvest window Fruit ripen unevenly Within plants Among clones Ripening rate influenced by biology/environment Pollination Position on stem and in cluster Temperature Sunlight Moisture availability

Harvest Window Temperature most important factor Growing degree day (GDD) model Predict harvest window GDD = (max C + min C)/2 5 C First ripe fruit ~650 GDD Maximum ripe fruit 1100 GDD 500 600 GDD after first ripe fruit (~6 weeks) 2 week harvest window Composition of ripe fruit did not change Soluble solids, Acidity, ph, Total Anthocyanins, Total Phenolics

Harvest Window Eaton 2009

Harvest Environment Rain Fruit turgidity Splitting Time of day Dew Temperature

Harvest Dry Fruit Wet fruit and debris stick together Reduced efficiency picking in wet fields Slower cleaning and sorting Greater susceptibility to splitting Free water on fruit encourages decay

Harvest Time - Temperature Fruit temperature Harvest at cool times of day Hot fruit Softer More prone to mechanical damage Avoid solar exposure Provide shade Cover fruit with reflective tarps Minimize time in field Cool within an hour of harvest

Harvest Method Minimal damage - high quality fruit Hand harvested fruit has longer storage life. Field packing may result in longer storage life Must ensure quality

Harvest Method Southern Highbush Blueberries Harvest method Hand Korvan 8000 blueberry harvester 70 Appearance 60 % Split % Shrivel 50 Hand Machine Day 0 5 40 4 Held overnight at 10 C (50 F) Percentage 30 20 10 0 60 50 40 30 Stored 14 days at 1 C 3 2 1 5 4 3 Appearance Rating (1-5) Commercial packing morning after harvest 20 10 0 Meadowlark Sweetcrisp Farthing 2 1 Cultivar Sargent et al. 2013

Physical Abuse Wild Blueberries Fruit dropped onto hard surface Stored 14 days 0, 5, 10 and 20 C Percentage 60 40 20 Marketable Split Shrivel Decay Average of all 4 temperatures 0 0 20 40 60 80 100 120 140 160 180 Drop (cm) Sanford et al. 1989

Harvest Method Wild Blueberries Machine harvesters Tractor driven Walk-behind Hand harvest Rakes

Packing and Handling

Physical Abuse during Packing and Handling Physical abuse of fruit reduces potential storage life Every bounce, bump, drop or squeeze Greater force equals more damage Each physical abuse is cumulative Harvest, packing and handling must be designed to minimize abuse of fruit

Washing Wet Handling Reduces marketlife of fresh fruit 60 50 Stored 14 days at 0, 5, 10 and 20 C Washed Unwashed Increases fruit splitting Percentage 40 30 20 30 20 Firmness (N) Decreased fruit firmness 10 10 0 0 Marketable Split Shrivel Decay Firmness Sanford et al. 1989

Field Packing Pack directly into punnets Least handling of fruit Pick into field containers Grade, sort and pack in field

Shed Packing Packing Line Automation Less labour Better quality control Sizer Color sorter Defect detection Punnet filling More abuse Reduces storage life Feed belt Punnet filler Sizer

Quality Loss during IQF Processing Fruit firmness decreased during processing Production stage Average % change* Firmness Splits Initial quality 36.9 N 33% Lug feed -3.5 +24.3 Splits increased Varied 7 to 576% among plants Winnower -14.1 +33.9 Raw to pre-freeze -38.5 ----- *Average of 10 processing plants Rodgerson et al. 1993

Cumulative Drops in IQF Processing Rodgerson et al. 1993

Minimize mechanical damage Reduce drops and hard impacts Keep equipment clean Process dry fruit Cleaning / Grading

Physical protection Low profile reduce compression Ridged sides/top Plastic Clamshells Packaging Adequate ventilation Breathable films Reduce water loss 34

Temperature Management

Harvested Fruit Are Alive Respiration CHO + O 2 CO 2 + H 2 O CO 2 CO 2 O 2 O 2 H 2 O H 2 O Respiration Transpiration 36

Temperature - Respiration Respiration Rate (mg kg -1 h -1 ) 100 50 0 0 5 10 15 20 25 20 10 0 Heat Produced (BTU T -1 d -1 x 1000) Temperature ( C) 37

Temperature Forced Air Cooling Highbush blueberry - An 8 h delay resulted in: Reduced firmness* Increased weight loss* Increased split and decayed fruit* *following storage Wild blueberry delay cooling Reduced firmness & marketable fruit Increased split fruit Forced air cooling is recommended method Firmness (g/mm) % Split 125 120 115 110 105 100 95 90 0 1 2 3 4 5 6 7 8 9 16 14 12 10 Cooling delay (h @ 20 C) Split Firmness 32 30 28 26 24 22 8 20 0 10 20 30 40 50 Cooling delay (h @ 5-26 C) Jackson et al. 1999 Firmness (N)

Forced Air Cooling Main Components Venting Fan Cold Air

Tunnel Cooler Forced Air Cooling

Cold-Wall Cooler Forced Air Cooling

Storage Temperature 0 to -1.0 C Maximize storage life Avoid freezing fruit Freezing point ~1.6 C

Storage Temperature Wild Blueberries Stored 14 days 0, 5, 10 and 20 C Fruit dropped - 0, 53, 106 or 159 cm Percentage 60 40 20 Marketable Split Shrivel Decay Average of all 4 drops 0 0 5 10 15 20 25 Storage Temperature ( C) Sanford et al. 1989

Benefits of Atmosphere Modification Carbon dioxide (10% + CO 2 ) Inhibits Botrytis Reduces Grey Mold Water vapor (H 2 O) Reduces weight loss Minimizes shrivel Slows compositional changes

Applying Atmosphere Modification Target atmosphere 10-12% CO 2 10-15% O 2 Avoid low O 2 <2% O 2 may cause fermentation Application CA rooms - not practical CA tents / pallet bags MAP

Blueberry Storage Pallet Racking CA Tents Zipper Pressure Relief Valve Sealed Tent Water Trough Open Door Loaded Pallet

Active Atmosphere modification Micro CA Pallet Storage Control Systems Palliflex system Van Amerongen

Passive Atmosphere modification Tectrol system TransFresh View Fresh Spectrum-Slider MAP bag

Conclusions Challenges / Opportunities Optimize fruit quality production practices & harvest timing Minimize mechanical damage during harvesting, cleaning, grading and packaging Cool and maintain optimum temperature (0 to 4 C) Use packaging that minimizes mechanical damage and reduces water loss Consider atmosphere modification to extend market-life