Understanding the mechanisms in fruit response to various storage conditions Implications for Australian growers and fruit quality management

Transcription

1 Understanding the mechanisms in fruit response to various storage conditions Implications for Australian growers and fruit quality management Chris Watkins Cornell University Ithaca, NY

2 NEW YORK STATE 2

3 NEW YORK STATE 3

4 Varieties McIntosh Empire Delicious Gala Cortland Jonagold Honeycrisp Many others incl. Fuji, Granny Smith, Pink Lady, club varieties

5 Plant growth regulators Aminoethoxyvinylglycine (AVG) Napthaline acetic acid (NAA) Prevent fruit drop Harvest and labor management Responses of fruit to SmartFresh

6 Cummulative fruit drop (%) Harvista - Preharvest application of 1-MCP Delicious untreated Harvista /10 10/17 10/24 10/30 11/6 11/9 11/14 11/21

7 Diphenylamine (DPA)

8 Diphenylamine (DPA) Non-recycling drench Thermofogging and Aerosol DPA EU issues - residues

9 Increasing investment in new CA storages

10 SmartFresh TM Technology heavily invested

11 Outline Brief postharvest basics Optimizing SmartFresh benefits Range of CA options, including Dynamic CA storage

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13 The apple is a climacteric fruit Increase in respiration is associated with autocatalytic ethylene production

14 The climacteric results in higher - Ethylene production Increased respiration Softening Loss of acidity Yellowing Aroma increases (but not necessarily good aromas) Respiration Loss of carbohydrates and other energy sources Rates of Respiration and ethylene production reduced by Low storage temperatures, low oxygen, higher carbon dioxide SmartFresh inhibits ethylene production and thereby respiration rate

15 Relative change Correct maturity is a compromise between quality and storage life required! STORABILITY (firmness, acidity, starch, background color) QUALITY (color, flavor, sugar/acid ratio, starch index) Maturation and ripening period

16 Effect of storage temperature on relative velocity of deterioration deterioration rate Storage temperature ( o C)

17 Respiration rate (ml CO 2 /10kg/hr) at different oxygen concentrations Oxygen concentration (%)

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19 Responses to 1-MCP and CA storage (and susceptibility to disorders) Combination of 1. Harvest timing combination of maturity, growing climate and PGRs 2. Postharvest handling As a generalization, most attributable to understanding ethylene production by the fruit, which also increases the respiration rate

20 ReTain, Harvista, NAA, ReTain and NAA - McIntosh with CA storage Harvest Sept 18 and Sept 21(3 d difference) ReTain 2 weeks (*before Sept 18) Harvista 1 week* NAA 3 days* ReTain + NAA

21 Internal ethylene concentrations (ppm) in response to Harvista, ReTain and NAA Sept 18 Sept

22 Sept 21 harvest: 4 months CA storage + 1 d firmness (Kg-f) No SF SF 5 4 untrt Harvista ReTain NAA ReTain + NAA

23 23 Ethylene during postharvest handling Effect of delaying application of SmartFresh Jonagold fruit harvested, cooled overnight. 1-MCP applied after 2, 7, 14 and 21 days in cold store IEC measured at time of treatment. Firmness measured after 5 months of storage in CA.

24 Jonagold, IEC (ppm) before 1-MCP and CA storage 12 IEC (ul/l) at harvest and at time of trt H 1 d 7 d 14 d 21 d

25 After 5 months CA 70 Firmness (N) Untrt 1 d 7 d 14 d 21 d

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27 27 CA methods O2 (%) CO2 (%) N2 (%) Refrigerated air Controlled ventilation Conventional CA LO ULO DCA/DCS <0.8 <1.5 >98

28 28 Conventional CA 2-5% O2 and 2-5% CO2 depending on cultivar Originally O2 reduced by respiration or burning, but modern systems use N2 to flush down the rooms Reliant on development of technology to remove CO2 produced by respiration from room atmosphere Can be manual control by measuring gas composition with hand-held gas analyzers, or by computer-based technology (typically wide fluctuations with manual) Used extensively worldwide

29 29 Low Oxygen (LO) and Ultra Low Oxygen (ULO) LO: % O2 and 1-3% CO2 depending on cultivar ULO: % O2 and 0.5-2% CO2 depending on cultivar Tightness of rooms must be much higher than conventional CA rooms O2 and CO2 must be maintained within 0.1% of set point Frequent measurements (min 4-6 hours) and adjustment of atmospheres are essential Therefore computer-based monitoring and control systems are important Worldwide but regional and cultivar specific; less emphasis since advent of SmartFresh

30 Maximal quality retention (green line) occurs when the storage O 2 (%) is at Lower O 2 Limit, LOL (= Anaerobic Compensation Point, ACP) Fermentation threshold

31 31 Dynamic CA <0.8% O2 with <1.5 variety dependent Based on philosophy that measurement of fruit physiology can indicate stress and that this signal can be used to maintain O2 levels above injurious levels. Dynamic in that it recognizes that fruit metabolism may change during the storage period Systems to date are based on fluorescence, ethanol and respiratory quotient (RQ)

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33 Sample container in open position showing sensor on lid Sample container in closed position Computer Hub for multiple sample containers

34 Using HarvestWatch to determine LOL in apple Decreasing O 2 LOL = ca. 0.8% O 2

35 The LOL (ACP) is dynamic! In this fruit sample, the LOL (ACP) is lower than the first sample Fermentation threshold

36 The LOL (ACP) is dynamic! In this fruit sample, the LOL (ACP) is higher than the first sample Fermentation threshold

37 37 HarvestWatch containers in storage bins

38 SmartFresh and DCA an interesting contrast Both technologies launched commercially in 2002, but market penetration of DCA greater in Europe than North America Registration for 1-MCP for food products in 2002 in US, Chile, Canada, New Zealand, but later in Europe (2006+) No registration for DCA required so available earlier in Europe DCA chemical free greater issue in Europe Where 1-MCP was available industries chose because of fewer room quality issues, concern about fruit variation, convenience and postharvest benefits

39 Storage technologies in South Tyrol (Italy) ( ) (3rd season without DPA) 3,4% 2,0% 17,9% CA/ULO 1-MCP 19,0% 57,8% DCA-CF (incl. MCP) ILOS (incl. MCP) RLOS (incl. MCP) Apple 800,000 tons Zanella

40 Marketing Early Late Storage Strategy replacing DPA DCA + MCP/SF DCA-CF MCP SmartFresh ILOS, CA/ULO, KL RLOS, DCA-CF Light, ILOS ILOS CA/ULO KL unbalanced/ young trees Start End over maturity HarvestWindow Zanella

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