Southeast Regional Fruit & Vegetable Conference January 9, 2015 Steve Sargent Extension postharvest horticulturist Horticultural Sciences Department University of Florida-IFAS sasa@ufl.edu
DEALING WITH SUCCESS!! How do increasing yields affect: Crew size needed for harvest Fruit wait time in the field Ability to minimize contamination Transport volume/time to packinghouse Time to cool to final pulp temperature
KEYS FOR SUCCESS!! Harvest at proper maturity Minimize mechanical damage Manage fruit temperature
Delayed Harvest may result in softer fruit
Fruit detachment force: cultivar, harvest maturity for 2 harvests
How Does Harvest Time Affect Quality?? Cvs. Emerald, Jewel, Primadona were harvested early, mid and late season For each harvest, fruit sorted and packed into 4.4 oz clamshells Cooled and stored at 37 o F Quality determined during 14 days storage
Weight loss after 0, 7, and 14 days at 37 F for harvests 1, 2, and 3. Emerald Jewel Primadonna 5 4 Weight Loss (%) 3 2 1 0 7d 14d 7d 14d 7d 14d Harvest 1 Harvest 2 Harvest 3
Brix/acid ratio after 0, 7, and 14 days at 37 for harvests 1, 2, and 3. Emerald Jewel Primadonna 20 18 16 14 Brix / TTA 12 10 8 6 4 2 0 0d 7d 14d 0d 7d 14d 0d 7d 14d Harvest 1 Harvest 2 Harvest 3 2010 Season
Causes of Mechanical Damage Fruit receive many impacts during harvest and handling
Typical handling steps and potential for mechanical damage Blueberry Handling Farm level Bush: Harvest Bucket Field Presorting Lugs/ Pallet Field Transportation 1 2 3 4 5 Potential point of damage Loading / unloading
Receiving/packing/cooling facility Road Transp. Overnight Cold Storage Sort/ Grade/ Pack/ Palletize Rapid Cooling/ Storage Shipping 7 8 9 10 11 Potential point of damage Loading / unloading
Transfer to field lug Blueberry harvest
Mobile collection/pregrading station
Portable collection/pregrading station
Example of a well-designed field lug: Cross-braces reduce vibration Short height better use of space Good ventilation when stacked
Transfer to packing area
Impact Damage to Fresh Blueberries
Impacts affect aroma volatiles Freshly harvested blueberries dropped 6 times from 8 inches (20 cm) and stored @ 36 o F (2 o C) Aroma volatiles measured during storage (after 2, 10, 17, 24 days ) Discriminant function analysis performed after separation of blueberry volatiles (Demir et al. 2011)
Discriminant Function Analysis showed impacts caused differences in aroma volatiles during storage
Demand for fresh-market blueberries continues to rise (Perez & Plattner, 2012) while harvest labor is becoming more scarce (Fonsah et al., 2008). Fruit are typically hand-harvested every 3 to 4 d during the picking season. However, in order for the fruit to be suitable for mechanical harvest, the harvest interval would need to be extended to every 7 to 10 d. This delay might accelerate fruit abscission and/or senescence.
Seasonal Packout: Hand v. Mech. Meadowlark Harvest Marketable Immature Soft Method Hand 92.1 6.2 1.7 Machine 84.1 11.9 4.0 Significance 0.0058 0.0133 0.0005 Farthing Harvest Marketable Immature Soft Method Hand 94.3 4.5 1.2 Machine 80.5 17.3 2.2 Significance 0.0039 0.0051 0.0356 Sweetcrisp Harvest Marketable Immature Soft Method Hand 95.3 3.7 1.0 Machine 77.4 20.6 1.9 Significance 0.0030 0.0006 0.0682
Visual Quality: Hand v. Mech. Harvest Cultiv. App Rat Hand Harvested and Stored Mech. Harvested and Stored 7 days 14 days 7 days 14 days Soft % Shr % App Soft % Shr % App Rat Soft % Shr % App Rat Soft % Shr % Harvest 1 M-lark 4.0 15.0 30.0 2.0 10.0 90.0 4.0 25.0 37.5 2.0 32.5 90.0 Farth. 4.0 10.0 17.5 3.0 30.0 27.5 4.0 25.0 5.0 2.0 75.0 50.0 Swtcrs 4.0 10.0 10.0 2.9 15.0 50.0 4.0 42.5 15.0 2.0 70.0 70.0
Flavor: Hand v. Mech. Harvest Initial Hand (14 d) Mech. (14 d) Cult. SSC TTA (%) SSC/TTA SSC TTA % SSC/TTA SSC TTA % SSC/TTA M- lark 7.7 0.5 16.6 a B 8.2 0.42 19.7 b A 7.7 0.3 24.5 a AB Far 10.8 0.7 16.3 a C 11.3 0.44 25.7 a A 10.7 0.5 20.9 a B Swcr 13.5 1.0 13.4 b B 13.7 0.82 16.9 c A 13.6 1.0 13.7 b B y Means (n=4) followed by the same lower case letter in a column or capital letter in the same row are not significantly different according to Duncan s Multiple Range Test (P<0.05).
Causes of Mechanical Damage Fruit several impacts during mechanical harvest Most severe occurs as the detached fruit falls to the catch plates on the harvester This impact is believed to be the major cause of fruit softening during storage
Delays to harvest on quality Objective: Evaluate mechanical and sensory quality of blueberries picked upon reaching blue color stage and after an additional 7 days on the plant.
Storage Quality
How long can cooling be delayed without affecting fruit quality? `Bonita rabbiteye blueberries picked, stored overnight at 36 o F and 90% relative humidity (RH) Next day, sorted into clamshells; warmed to 86 o F Cooled to 39 o F after 2, 4, 6 or 8 hour delay Stored at 36 o F and evaluated weekly
Delays to Cooling: Results Incidence of unmarketable fruit (%) Delay (hr) Week 1 Week 2 Week 3 Week 4 0 0 0 50.0 42.5 2 0 0 47.5 22.5 4 0 0 40.0 47.5 6 0 0 35.0 60.0 8 0 0 27.5 70.0
Delays to Cooling: Results Weight loss during storage
Delays to Cooling: Results Firmness During Storage
Conclusions Weight loss: Cultivar-dependent Cooling delays over 6 hours = loss during storage Fruit firmness: softening, abscission with delays to harvest Fruit flavor: Cultivar-dependent Regular harvest time - minor effect Delayed harvest time - sweeter
Conclusions (cont.) Mechanical Harvest (vs. Hand Harvest): Cultivar differences soft fruit at harvest and during storage Shrivel symptoms didn t correlate with soft fruit flavor
Questions??