Best Practices for use of SmartFresh on Pear Fruit Beth Mitcham Department of Plant Sciences University of California Davis
1-Methylcyclopropene Cyclic olefin gas Inhibitor of ethylene binding and action Effective at nanomolar concentrations Registered as SmartFresh TM for postharvest use on fruits CH 3 Treated with 3 ppb 1-MCP
Potential Benefits of SmartFresh TM Extend storage life in air or CA storage Reduce development of storage disorders Enable warmer temperatures in storage to save energy Shipment of fruit to tropical climates or areas without cold chain
Factors Influencing Pear Fruit Response to Smartfresh TM Variety Growing Location Maturity Fruit ethylene production Temperature during delay after harvest
Differences in Variety Response to SmartFresh Bartlett - 3 ppb Anjou - 2 ppb Bosc - 3 ppb Rocha - 316 ppb (report from literature) Packham - 2 ppb (report from literature) Abate Fetel - < 3ppb (report from literature) Related to the fruit s general ripening capacity and ethylene production at harvest
Growing Locations Pacific Northwest Bartlett 3 ppb California Bartlett 3-6 ppb
Senescent Scald (%) 1 8 6 4 2 Influence of Elevation and Harvest Maturity on Efficacy of SmartFresh to Control Senescent Scald in Bartlett Pears Solid color = Elevation 15m Patterned = Elevation 61m Wang & Sugar 215 Control 1-MCP Control 1-MCP Harvest 1 Harvest 2
Senescent Core Breakdown (%) 8 6 4 2 Influence of Elevation and Harvest Maturity on Efficacy of SmartFresh to Control Senescent Core Breakdown in Bartlett Pears Solid color = Elevation 15m Patterned = Elevation 61m Control 1-MCP Control 1-MCP Wang & Sugar 215 Harvest 1 Harvest 2
Competition Between SmartFresh and Ethylene Internal ethylene levels increase during ripening and reduces 1-MCP efficacy Accumulation of ethylene in the 1-MCP treatment atmosphere will reduce efficacy CH 3 CH 3 CH 3
Methodology Early-, mid- and late-season Bartlett pears were harvested from two growing regions in CA Fruit were cooled to o C and exposed to the following treatments for 24 hours at o C Control (no 1-MCP or ethylene) 1-MCP only (6 nl/l) 6 nl/l 1-MCP & 12 nl/l ethylene (5:1) 6 nl/l 1-MCP & 3 nl/l ethylene (2:1) 6 nl/l 1-MCP & 6 nl/l ethylene (1:1) 6 nl/l 1-MCP & 6 nl/l ethylene (1:1) Fruit were then ripened at 2 o C
Effect of Ethylene on Response to SmartFresh on Bartlett Pears IEC =.4 ±.1 ppm IEC =.16 ±.2 ppm IEC = 3.98 ± 1.18 ppm Flesh firmness (lbs) 2 15 1 5 SmartFresh TM treatment Ethylene challenge Early-season Mid-season Late-season SmartFresh TM treatment Ethylene challenge Control SF only 5 SF:1 C 2 2 SF:1 C 2 1 SF:1 C 2 1 SF:1 C 2 SmartFresh TM treatment Ethylene challenge AH 3 6 9 12 15 AH 3 6 9 12 15 AH 3 6 9 12 15 Time (days) SmartFresh TM effects are diminished for later harvests in association with higher ethylene production by fruit
Control SF only 5 SF: 1 C 2 Early season fruit Day 9 at 2 o C 6 ppb 1-MCP 2 SF: 1 C 2 1 SF: 1 C 2 1 SF: 1 C 2
Predicting an optimal [SmartFresh TM ] Based on observations from the 21 season Flesh firmness (lbs) 2 Control SF only 5 SF:1 C 2 15 1 5-3 3 6 9 12 15 Harvest SmartFresh SM treatment Ethylene challenge Time (days) 2 SF:1 C 2 1 SF:1 C 2 1 SF:1 C 2 Ethylene build-up in tanks during treatment Ethylene Treatment concentration (ppm) Beginning End End ratio Control..172 - SF only..56 11:1 5 SF:1 C 2.17.86 7:1 2 SF:1 C 2.34.18 5.5:1 1 SF:1 C 2.72.173 3.5:1
Late season fruit (IEC = 3.98 ± 1.18 µl/l) Late Season Bartlett Pears Flesh firmness (N) 1 8 6 4 2-3 3 6 9 12 15 Harvest SmartFresh SM treatment Ethylene challenge Time (days) Control SF only 5 SF:1 C 2 2 SF:1 C 2 1 SF:1 C 2 1 SF:1 C 2 Ethylene build-up in tanks during treatment Treatment Treatment Ethylene concentration (µl/l) Ethylene concentration (µl/l) Beginning End Beginning End End ratio Control.7.258 SF only.7.224 Control.7.258-5 SF:1 C 2.19.48 SF only.7.224 2.7:1 2 SF:1 C 2.36.547 51 SF:1 C 2 H 24.67.19.688.48 1.3:1 1 SF:1 C 2.65 1.573 2 SF:1 C 2.36.547 1.1:1 1 SF:1 C 2.67.688.9:1
Predicting an optimal SmartFresh TM Concentration Steps involved: 1. Cool fruit to treatment temperature 2. Seal fruit in jars for 12-15 hours 3. Measure the ethylene concentration that accumulates in jars 4. Calculate the concentration of ethylene that would accumulate around pears in 24 hours 5. Predict an optimal SmartFresh TM concentration: [optimal SF} = 3.5 X [ethylene]
Ability of Pear Fruit to Ripen After SmartFresh Treatment
Firmness (N) after 7d @ 2 C Influence of Elevation and Harvest Maturity on Recovery of Ripening Capacity following Treatment with SmartFresh in Bartlett Pears 7 6 5 4 3 2 1 3 months 5 months 6 months Solid color = Elevation 15m Patterned = Elevation 61m Control 1-MCP Control 1-MCP Wang and Sugar 215 Harvest 1 Harvest 2
Firmness (N) after 12d @ 2 C 6 5 4 3 2 1 Influence of Elevation and Harvest Maturity on Recovery of Ripening Capacity following treatment with SmartFresh in Bartlett Pears 3 months 5 months 6 months Solid color = Elevation 15m Patterned = Elevation 61m Control 1-MCP Control 1-MCP Wang and Sugar 215 Harvest 1 Harvest 2
Changes in firmness during storage and post-storage shelf-life of Rocha pears treated with 312 ppb 1-MCP Firmness (N) 7 6 5 4 3 2 1 At harvest 14 wks = 3 ½ mo; 26 wks = 6 ½ mo., 35 wks = 8 ¾ mo. 2.5 C + air 2.5 C + CA C + air C + CA 14 14+1 14+2 26 26+1 26+2 35 35+1 35+2 Time (weeks) Gago et al., 213
Incidence of internal browning during storage and shelf-life of Rocha pears treated with 312 ppb 1-MCP Internal Browning (%) 12 1 8 6 4 2 At harvest 14 wks = 3 ½ mo; 26 wks = 6 ½ mo., 35 wks = 8 ¾ mo. 2.5 C + air 2.5 C + CA C + air C + CA 14 14+1 14+2 26 26+1 26+2 35 35+1 35+2 Time (weeks) Gago et al., 213
Firmness (N) 8 6 4 2 Influence of Storage Temperature and SmartFresh Treatment on Firmness of Anjou pears During Storage Control@-1.1 C 1-MCP@-1.1 C 1-MCP@1.1 C 1 2 3 4 5 6 7 8 Months in Storage 15 1 5 Firmness (lbs.-force)
Internal Ethylene (µl l -1 ) 4 35 3 25 2 15 1 5 Influence of Storage Temperature and SmartFresh Treatment on Ethylene in Anjou Pears During Storage Control@-1.1 C 1-MCP@-1.1 C 1-MCP@1.1 C Solid line = Internal Ethylene Dashed line = Ethylene Production 1 2 3 4 5 6 7 8 Months in Storage 16 14 12 1 8 6 4 2 Ethylene Production (pmol kg -1 s -1 )
Effect of SmartFresh and Storage Temperature on Recovery of Ripening Capacity (7d) in Anjou Pears Fruit Firmness (N) after 7d @ 2C 7 6 5 4 3 2 1 Control@-1 1 C 1-MCP@-1 1 C 1-MCP@1 1 C 1 2 3 4 5 6 7 8 Months in Storage
Effect of SmartFresh and Storage Temperature on Recovery of Ripening Capacity in Late Harvested* Anjou Pears Firmness (N) after 7 d at 2 C (N) 7 6 5 4 3 2 1 Control@-1.1 C 1-MCP@-1.1 C 1-MCP@1.1 C 1 2 3 4 5 6 7 8 Months in Storage 14 12 1 8 6 4 2 Firmness (lbs.-force) * 59N
Superficial Scald Incidence (%) 12 1 8 6 4 2 Influence of Storage Temperature and SmartFresh Treatment on Superficial Scald Development in Anjou pears Control@-1.1 C 1-MCP@-1.1 C 1-MCP@1.1 C 1 2 3 4 5 6 7 8 Months in Storage
Can We Achieve Extension of Storage Life AND Fruit Ripening after Harvest? Amit Dhingra will speak to a possible solution in next session
How Does SmartFresh Affect Sensory Quality of Pears This is experience we want our consumers to have!
Experimental Design Northern California (Lakeport) orchards Three weekly harvests Three Treatments 1 ppm Ethylene at 68 F for 24 hours 6 ppb gaseous 1-MCP at 34 F (2C) for 24h Control Ripen fruit at 68 F (2C) Evaluate objective and sensory quality when fully ripe 3 lbs.-force (13N)
Firmness (lbs) 25 2 15 1 Softening of California Bartlett Pears at 68F (2C) Early Season Mid Season Late Season 2C Control 24h. 1 ppm C2H4 24h. 6 ppb 1-MCP 5 2 4 6 8 1 12 14 16 18 2 22 2 4 6 8 1 12 14 16 18 2 22 2 4 6 8 1 12 14 16 18 2 22
Sensory Profiles: Early Season Fermented aroma Green aroma Pear aroma Apple aroma 2C Control 24h, 1 ppm Ethylene 24h, 6 ppb 1-MCP Firmness 1 2 3 4 5 6 7 Overall intensity aroma Juiciness Fruity taste Grittiness Sw eet taste Tart taste
Sensory Profiles: Late Season Early Season Green aroma Pear aroma Fermented aroma Apple aroma Firmness Green aroma Fermented aroma Pear aroma 2C Control 24h, 1 ppm Ethylene 24h, 6 ppb 1-MCP Juiciness Overall intensity aroma 1 2 3 4 5 6 7 Apple aroma Fruity taste Grittiness Sw eet taste Tart taste Firmness Green aroma Pear aroma Mid Season 1 2 3 4 5 6 7 Overall intensity aroma Fermented aroma Apple aroma Juiciness Firmness Juiciness Overall intensity aroma 1 2 3 4 5 6 7 Fruity taste Grittiness Sw eet taste Tart taste Fruity taste Grittiness Sw eet taste Tart taste
SmartFresh Treated Bartlett Pears* Have Better Sensory Quality Once Fully Softened Enhanced sweetness, juiciness and pear aroma Minimized fermented aroma, gritty texture and tart taste Packham pears treated with 2 ppb 1-MCP had greater sweetness and aroma than cold stored and CA stored pears after 4 and 6 months storage *California-grown fruit Escribano et al., 216. Postharvest Biol. Technology Moya-Leon et al., 26 Postharvest Biol. Technology
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