pom212_soft_fruit_2005_handout

pom212_soft_fruit_2005_handout - Soft Fruit Morphological...

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Unformatted text preview: Soft Fruit Morphological Characteristics • Simple fruits – Berries • Blueberry, cranberry, currant, gooseberry – Drupe raspberry strawberry • Huckleberry • Multiple fruits – Mulberry • Aggregate – Drupe • Blackberry, loganberry, raspberry – Achene • strawberry cranberry blueberry Strawberry is an Achene Fruit Changes in Strawberry Fresh Weight, Anthocyanin Content, and Ethylene Production 10 20 Days after Anthesis 30 Changes in Strawberry Respiration, Firmness and Cellulase Activity Repiration Rates and Ethylene Production Respiration Respiration Ethylene @ 5ºC 5º @ 0ºC @ 20ºC 0º 20º 22 155 <0.1 6 68 0.1 to 1.0 3 18 24 200 15 127 <0.1 16 130 10 58 58 Fruit Blackberry Blueberry Cranberry Raspberry Strawberry Currant Gooseberry 1 Climacteric verses Nonclimacteric • Blueberry is climacteric • Strawberry and raspberry are nonclimacteric – Strawberry has negative feedback response to ethylene • Decreased ethylene production and ACC levels Stages of Strawberry Color Development Minimum color at harvest U.S. - ½ to ¾ pink Calif. - 2/3 pink • Question about blackberry – Conflicting reports – How can we test for certain? Antisense of Strawberry Pectate Lyase Gene • Completely suppressed gene expression in three lines • Fruit were approximately twice as firm as non-transformed lines at red stage non• Softening during 4 days at 25ºC was 25º reduced to varying degrees in the three lines. – In one line, only 5% of the fruit were soft after 4 days at 25ºC 25º • Less cell wall swelling and less ionicallyionicallybound pectin 2 Quality Factors for Strawberries Degree of Ripeness Presence of Gloss Absence of Defects – Decay – Misshapen fruit – Unripe fruit • Berry Size and Uniformity • Firmness • Flavor • • • Postharvest Decay Organisms for Soft Fruit Botrytis cinerea Rhizopus stolonifer • • • • • • Methods of Decay Control Temperature management CA or MA, especially elevated CO2 Acetaldehyde vapor Chitosan coating Biological control Heat therapy – air and water – Blueberry and strawberry • Irradiation • Ozone in air – up to 0.3ppm on blackberry 3 Effects of CA on Strawberries • Enhanced fruit firmness after as few as 2 days in 20% CO2 • Whitening of strawberries • Off-flavors can develop due to Offaccumulation of ethanol and ethyl acetate – After 3 days at 20% CO2, dissipated after 24h in air at 20C – Off-flavors persistent after 7 days at 20% CO2 Off- • Reduced Vitamin C content after 10 to 30% CO2 – also in blackberries and currants – also greatly influenced by water loss Mean Diameter of Botrytis cinerea Lesions As Affected by Controlled Atmospheres Treatment Air Air + Ethylene Air + 15% CO2 Air + 10% CO CA CA + Ethylene CA + CO Aiko 7.5c 39.1f 2.0a 3.6b 11.8d 16.6e 0.6a G-3 62.7e 86.8f 2.6a 44.8d 21.8b 30.2c 1.6a G-4 45.0c 61.3d 2.9a 33.3b 27.7b 31.0b 2.2a Fruit needle inoculated before 21d storage Mean separation within columns CA = 2.3% O2 + 5% CO2 20 ppm ethylene 4 Effect of Controlled Atmospheres on Mycelial Infection and Nesting by Botrytis cinerea Treatment Air Air + Ethylene Air + 15% CO2 Air + 10% CO CA CA + Ethylene CA + CO 20 fruit around 1 inoc. fruit before storage inoc. Mean separation within columns Number of Rotted Berries (20 fruit) 19.3e 20.0e 0.2a 16.0c 14.0b 17.6d 0.2a CA = 2.3% O2 + 5% CO2 20 ppm ethylene Effect of High Oxygen Atmospheres on Strawberry Decay • Suppressed growth of microorganisms • Less effect on fruit quality – Fermentative metabolism Growth of Microorganisms Under Varying Oxygen Atmospheres 120 120 100 80 Anaerobes Aerobes 60 40 20 (Day, 1996) 0 0 20 40 60 % Oxygen 80 100 Mycelial Growth After Elevated Oxygen Treatment 100 Diameter (mm) 80 60 40 20 0 5d 7d Storage Time 14d Air 40% O2 60% O2 80% O2 90% O2 100% O2 40% O2 + 15% CO2 15% CO2 Strawberry Decay After 14d Elevated Oxygen Treatment 3 Decay Scale 2 1 0 14d 14+2d 40 Decay Scale: 0 = none; 1 = slight; 2 = moderate; 3 = severe 15 % % CO O 2+ 2 15 % CO 2 40 % O 2 60 % O 2 80 % O 2 90 % O 2 10 0% O 2 Treatment Ai r 5 Ethyl Acetate Concentrations After Elevated Oxygen Treatment Ethyl Acetate ( l/L) 180 135 90 45 0 90 2 % 10 O 2 0% 40 O 1 % 5% 2 O 2+ CO 15 2 % C O 2 2 In iti al Ai r 2 O O O % % 40 60 80 % 14d 14+2d Acetaldehyde Concentrations After Elevated Oxygen Treatment Acetaldehyde ( /L) 80 60 40 20 0 l Ai 40 r % O 60 2 % O 80 2 % O 90 2 % 10 O2 0% 40 15 O %2 % O 2+ CO 15 2 % C O 2 In iti a 14d 14+2d Treatment Treatment Ethanol Concentrations After Elevated Oxygen Treatment 1200 Ethanol ( l/L) 900 600 300 0 A 40 ir % 60 O2 % 80 O2 % 90 O2 % 10 O2 0% 40 1 % 5 % O2 O 2 + CO 15 2 % C O 2 In iti al 14d 14+2d Conclusions • 100% O2 suppresses mycelial growth better than 15% CO2 after 14d, but not as well after 5 or 7d • Less decay on strawberry fruit treated with 90% and 100% O2 vs. 15% CO2 • No residual protection • Feasibility of commercial application questionable Treatment Botrytis cinerea Conclusions % Germination 100 Hot Water 80 • No effect of atmospheres on firmness, color, soluble solids, titratable acidity, respiration and ethylene production • Volatile production : – Ethanol higher @ > 40% O2, similar to 15% CO2 – Acetaldehyde @ above 40% O2 > 15% CO2 , but but similar after 2d – Ethyl Acetate < than with 15% CO2, but greater after 2d – Combination of O2 + CO2 does not alleviate and may exacerbate volatile accumulation 60 40 20 0 5 10 15 5 10 15 20 25 30 1 3 5 min 40°C 45°C 50°C 6 Pichia guilliermondi 6 Candida oleophila 6 Hot Water 5 Hot Water 5 Log10 of CFU/ml Log10 of CFU/ml 4 4 3 3 2 2 1 1 0 5 10 15 40°C 30 5 10 15 45°C 30 1 3 5 7 50°C 10 min 0 5 10 15 40°C 30 5 10 15 45°C 30 1 3 5 7 50°C 10 min Aureobasidium pullulans 5 Hot Water Population Dynamics Experiment • Treatments: – Biocontrol alone (Pichia guilliermondii) – Biocontrol + 15% CO2 (B + C) – Biocontrol + Heat* (B + H) – Biocontrol, CA + Heat (B, C + H) • Population at wounds evaluated • 5 and 14 d at 5 °C + 2 d at 20 °C *63°C 15 sec. *63° 4 Log10 of CFU/ml 3 2 1 0 5 10 15 40°C 30 5 10 15 45°C 30 1 3 5 7 50°C 10 min Population Dynamics Pichia guilliermondii on Strawberries a Heat, Biological Control and CO2 for Control of Botrytis on Strawberry • Treatments: - Air - Biocontrol* Biocontrol* - Heat (63C, 15 sec) - CA (15% CO2) - Bio + CA (B + C) - Bio + Heat (B + H) - CA + Heat (C + H) - Bio, CA + Heat (B, C + H) 600 Colony Forming Units 500 400 1d 5d 5+2d 14 d 14 + 2 d b a b a ab a ab 300 200 100 c ab bb a b a * b b c c • • • Wound inoculated Diameter of lesion at wound measured 5 and 14 days at 5 ºC + 2 d at 20 ºC 0 Biocontrol B+H B+C B+C+H *Pichia guilliermondii Treatment 7 5 d Lesion Diameter a 14 d Lesion Diameter Lesion Diameter (mm) 20 a Lesion Diameter (mm) 10 ab 5d 5+2d bc c bc 8 6 4 b bc 14 d 14 + 2 d b b bc 15 a a cd 10 a d d d 2 ab ab b d a b b ab ab ab 5 c c 0 C on tro l H ea t c C A co nt ro C l A + H ea t Bi o + C A Bi o + H Bi ea o, t C A + H t 0 l C on t H ea t ro c Treatment Combination Treatments Conclusions • Removal of berries from CA to air caused a spike in biocontrol populations • Treatments did not adversely affect quality parameters • Combination of all three treatments most effective decay control after 5 + 2 d • Still most effective after 14 + 2 d, but not different from CA alone Conclusions • Combinations of heat and CA, heat and biocontrol and CA and biocontrol can have increased efficacy for decay control • The increase in yeast populations after exposure to CO2 should be further explored • Combination treatments should be explored on other commodities Use of Acetaldehyde for Decay and Insect Control C A Bi oc on tro C l A + H ea t Bi o + C A Bi o + H Bi ea o, t C A + H t Bi o Treatment 8 100 1.6 Acetaldehyde Concentration (%) 80 Mean Mortality (%) 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 0 20 40 60 80 100 120 140 160 180 Time (minutes) 0% Load factor 0.5% Load factor 2.1% Load factor 4.3% Load factor 60 40 two-spotted spider mite melon aphid western flower thrips 0.0 0.4 0.8 1.2 1.6 2.0 20 0 Acetaldehyde Concentration (%) Percent Mortality and Strawberry Quality Following Acetaldehyde Exposure Acetaldehyde Acetaldehyde (%) (%) Western Western Flower Thrips Flower Thrips Two-spotted Calyx Two-spotted Calyx Spider Mite Damagezz Spider Mite Damage Berry Berry Damagezz Damage Effect of a Two Hour Fumigation with Acetaldehyde on Strawberry Calyx 0 0 1 1 2 2 3 3 4 4 15.1 15.1 12.3 12.3 89.0 89.0 93.8 93.8 95.1 95.1 10.6 10.6 14.6 14.6 39.9 39.9 73.6 73.6 93.3 93.3 1.8b 1.8b 1.6a 1.6a 1.7ab 1.7ab 2.7c 2.7c 3.3d 3.3d 1.1a 1.1a 1.2a 1.2a 1.2a 1.2a 1.2a 1.2a 1.2a 1.2a 3% 4% control 1% 2% zDamage score: 1 = none; 2 = slight; 3 = moderate; 4 = severe z load factor 13%; 1 h at 24°C 0°C Day 0 Acetaldehyde -1 (µmol mol ) 60 40 15 10 5 0 Ethanol (µmol mol-1) 20°C Day 4 Acetaldehyde (µmol mol-1) 40 15 10 5 0 400 200 0 Day 2 Day 0 Day 1 Day 2 Ethanol (µmol mol-1) 400 200 0 120 80 40 0 Ethyl Acetate (µmol mol-1) Ethyl Acetate (µmol mol-1) Air CO2 120 80 40 0 Air CO2 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 0 1 2 3 4 Acetaldehyde Concentration (%) Acetaldehyde Concentration (%) 9 Other Acetaldehyde Effects • Improved aroma and flavor • A 1 hour exposure to 2.5% AA killed spores of Botrytis cinerea and Rhizopus stolonifer • Fruit tolerate between 2 and 3% AA Cranberry Harvest • Two mechanical harvest methods – Dry and wet • Wet – More fungal rot if fruit remain in bog more than 24h – With 12+ hours in bog, increase in physiological breakdown – Time immersed had a greater effect on physiological breakdown than decay Harvest Methods • Strawberry and raspberry – Hand-harvest Hand- Cranberry Health Benefits • Phenolic compounds – Anthocyanins, flavonoids, condensed Anthocyanins, flavonoids, tannins, proanthocyanidins, low proanthocyanidins, molecular weight phenolic acids • Blueberry and cranberry – Mechanical or hand harvest • Health claims – Prevent bacterial adhesion in urinary tract infections of E. coli and stomach ulcers – Protection against lipoprotein oxidation – In vitro anticancer activity • Effects on postharvest quality Strawberries Growing on Raised Beds Beds Covered in Plastic Hand Harvest 10 Nesting of Botrytis Rot Harvest, Sort, and Pack in the Field One Bad Berry can Destroy the Whole Tray Harvest Operation Pick, Pack, and Palletize in the Field Inspection and Quality Control Twelve One-Pint Mesh Baskets One- Eight One Pound Clamshell Baskets Rough basket can cause damage Slightly slower cooling Protects berries from damage 11 Two Trays are Connected with Wire Stabilizes Pallet Keep Berries out of the Sun Transport Fruit to Cooler Shortly After Harvest 12 Forced-Air Cooling of Strawberries Forced- Effect of Temperature Fluctuations on Strawberry Quality Pallet Covers for Carbon Dioxide Treatment of Strawberries during Transport Effect of Temperature and Carbon Dioxide on Growth of Botrytis cinerea Lesions on Strawberry 13 Center-Line Loading CenterRefrigerated loading dock! 14 Raspberries Multiple Harvests are Required Gentle Harvest by Hand Harvest into small containers to avoid bruising! Ranch Packing for Raspberry Inspection and quality control 15 Packing in Fiberboard Box with Plastic Wrapper Has Been Replaced with Plastic Clamshell Packed Tray of Raspberries Similar design to that for strawberry Pallet covers are used similar to strawberries Blueberries Hand Harvest of Blueberries 16 Current blueberry research is evaluating: Techniques for controlling soil pH Pruning impacts on time of fruiting Variety selection Hot tunnel effects Plant spacing Reduce Handling to Maintain Waxy Bloom Machine Harvest of Blueberries Field Totes Dumped onto the Packingline Effect of Harvest Method and Cultivar on Blueberry Quality 17 Filling Clamshell Containers Sorting by Hand Blueberry Tray & Clamshell Basket Palletize packed fruit 18 Cranberry Bog Cranberry Bog with Fruit Dry Harvest of Cranberry Wet Harvest of Cranberry Floating Cranberries are Pumped Out of the Bog 19 Future Research • Benefits of harvesting raspberries directly into clamshells • Genetic manipulation to increase sweetness and flavor of all fruits – Traditional breeding or GMOs – Retain firmness of red fruit with high SS • Systems approach to fungal control • Develop a method to detect food-borne foodpathogens • Benefits of high CO2 on cranberry • Phytochemical composition Future Research 20 ...
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