pom212_pome_fruit_handout

pom212_pome_fruit_handout - APPLES Pome Fruit •...

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Unformatted text preview: APPLES Pome Fruit • Cartilaginous endocarp • Edible portion is receptacle tissue • Remnants of flower parts at blossom end • Sclereid cells in pear flesh and skin – Stone cells with thick cell walls Harvest date influences postharvest life and quality!! •Red color development •Background color •Firmness •Sugar to acid ratio •Flavor volatiles •Presence of or susceptibility to disorders Goal Maximize Storage life Blush Sensory quality – – – Crispness Flavor Sweetness • • • Minimize • Softening and mealiness • Disorders – – – – Bitter pit Scald Internal browning Checking • Size Apples and Pears are Climacteric Fruit Many Changes Occur as Fruit Approach Maturity RS Rate First 30 d of development are critical Time 1 Indicators of Harvest Maturity • # Days from full bloom • Time/temp (heat units) from anthesis • Days from harvest to onset of ethylene production • Ground color • Soluble solids content • Flesh firmness and SSC • Starch disappearance pattern • Internal ethylene concentration • Changes in firmness or starch content Indicators of Harvest Maturity? Starch Content is a Common Indicator of Harvest Maturity Starch Determination with Iodine/Potassium Iodide Granny Smith Apples Granny Starch Staining Warm Temperatures and Ethylene Treatment Promote Starch Conversion to Sugar in Apples Initial Fruit Quality Determines the Ripened Quality!! Cold Storage Only Air Ethylene Ethylene 6 d @ 25°C (75°F) 25° (75° 2 Fruit Quality • Flavor – Volatiles, acids, sugars Controlled Atmosphere Storage Store 1.5 to 12+ months 0.7 to 3% oxygen 0.5 to 4% carbon dioxide Maintains firmness, ground color and acidity by reducing respiration and the effects of ethylene • Reduces storage scald and bitter pit • May induce disorders such as internal browning • • • • • Texture – Crispness, lack of mealiness • Appearance – Color, gloss, lack of defects • Effect of harvest maturity • Effect of controlled atmosphere storage Controlled Atmospheres • Rapid CA – Establish in 1 to 3 days compared with 20 days Internal Browning of Fuji Apples CO2 Injury • • • • • CO2 Concentration Temperature Harvest Date Orchard Factors Seasonal Factors • High CO2 or low O2 initial shock 2 2 – 20% CO2 for 2 hours 2 • Greater effect on ACC oxidase activity – 0.5% O2 for 1 to 3 days 2 • Greater inhibition of storage scald • Ultra-low O2 CA UltraUltra-low 2 • Dynamic controlled atmospheres – Ethanol or chlorophyll fluorescence Effect of Carbon Dioxide Concentration on Internal Browning Effect of Harvest Date on Susceptibility to Internal Browning 3 Internal Browning in Controlled Atmosphere Use of 1-MCP on Apples 11-MCP • Binds to ethylene receptor • Inhibits ethylene action • Inhibits ethylene production, softening, storage scald development, bitter pit • Inhibits volatile production • May reduce or enhance decay Frequency of Disorders & Diseases Reported in USDA Inspections of Apple Shipments Disorder Blue mold rot Gray mold rot Bruise damage Scald Scarring Bitter pit Cuts/punctures Internal breakdown Shriveling Watercore Sunburn Sodium Injury from Liquid Chlorine Shipments Affected (%) 32.7 1.1 75.1 4.6 3.8 3.5 3.3 2.0 0.4 0.2 0.1 Cappellini 1987 Sodium Injury from Liquid Chlorine A Fresh Water Rinse can Prevent Sodium Injury Granny Smith Apples 2 min in 1500 ppm Na No Rinse 15 Second Rinse 1 minute Rinse 4 Bitter Pit Low calcium, high nitrogen Vigorous trees Water stress Large fruit Low maturity fruit Develops on tree or during first 4 to 6 weeks of storage • Control with calcium applications • • • • • • Hypothesis of Bitter Pit Development • High GA levels late in season – Excessive root activity • High GA leads to increased permeability of cell membranes near vascular bundles – Increases sensitivity to water stress • Calcium levels may be a secondary factor that reduces fruit susceptibility • Calcium may stabilize cell membranes and reduce their permeability Saure, 1996; Germany Saure, Watercore • Disorder of vascular bundles • Sorbitol remains in intercellular spaces, promotes water retention • Associated with high maturity fruit • Can disappear in storage or turn brown – Anaerobic • Altered membrane lipids An accumulation of sorbitol in the intercellular spaces 5 Sunburn on Apples Storage Scald on Granny Smith Apples •Damage occurs in the field •May turn brown in storage •Usually on one side of fruit Storage Scald α farnesene α farnesene precursor (+) ethylene (-) DPA, low O2, 1-MCP O2 low O2 (-) antioxidants (-) Death of epidermal cells!! Oxidation of epidermal cell lipids conjugated trienols Storage Scald • A type of chilling injury • Cultivars vary in susceptibility • Higher in low maturity fruit, low calcium levels • Higher in fruit grown in hot, dry climates • Cool temperatures before harvest may reduce susceptibility – Hours < 10ºC predict susceptibility 10º 10ºC • Antioxidants in peel reduce susceptibility Control of Storage Scald • Old method - oil wraps and ventilation of storage • Antioxidants such as diphenylamine and ethoxyquin on pears • Controlled atmosphere storage – Ultra-low oxygen UltraUltra-low – Initial low oxygen stress Effects of Controlled Atmosphere on Bitter Pit and Storage Scald • 1-methylcyclopropane (SmartFresh) 1-methylcyclopropane (SmartFresh) (SmartFresh) • Pre-storage heat treatments PrePre-storage 1.5% O2; 1% CO2 6 Penicillium expansum on Apple Mealiness • Soft texture causing a dry feeling in the mouth during mastication – Low adhesion between cells • Measure tensile strength, force to pull apart •Wound pathogen •Controlled by low-temperature storage low- – Retain strong cell walls • Place cells in greater and greater osmotic solution until they burst • Cells pull apart instead of breaking when you bite – no juicy sensation Botrytis Rot on Apple Side, stem or blossom infections Growth is reduced at 0°C 0° Mucor Rot (Mucor piriformis) (Mucor piriformis) •Organism lives in soil •Do not pick up grounders •Keep soil off field bins Core Rot in Apple •Can begin in field or after harvest •Difficult to detect European Pears 7 Harvest Maturity • Immature fruit – more susceptible to shrivel – lower ethylene production • Advanced maturity fruit – more susceptible to breakdown in storage – higher ethylene production European Pears are Harvested Unripe, but Mature Fiirmness F rmness (llbs..-force) ( bs -force) Bartllett Bart ett 19 - 20 19 - 20 20 - 21 20 - 21 20..5 – 21..5 20 5 – 21 5 21 - 22 21 - 22 D’’Anjjou D An ou Comiice Com ce Bosc Bosc 10 - 15 10 - 15 9-13 9-13 11 - 16 11 - 16 Sollublle Solliids So ub e So ds < 10% < 10% 10 10 11 11 12 12 Comice Forelle Starkrimson Bosc 8 Anjou Red Bartlett Bartlett Factors Affecting Pear Quality • • • • • • • Harvest maturity Delays before cold storage Speed of cooling Storage temperature Relative humidity in storage Length of storage Storage atmosphere - O2, CO2, ethylene Pear Ripening • Do not ripen to good quality on the tree • Need cold storage to induce synthesis of ethylene biosynthesis enzymes • ACC oxidase is induced in cold storage before ACC synthase • Loose ability to ripen after extended storage – Not due to lack of ethylene production Bartlett Pears Harvested and Immediately Ripened 8d air 20°C 20° 1d C2H4 7d air 20°C 20° 9 20 Firmness (lbs) 16 12 8 4 0 Air 100 ppm ethylene 24 hr 60 40 20 0 Firmness (N) 80 Why do Pears Need Cold Storage or Ethylene Treatment? • Pears have insufficient capacity to produce ethylene at harvest – lack of precursor, ACC Ethylene production (µl•kg-1h-1) 40 20 0 0 1 2 3 4 5 6 7 • ACC accumulates during cold storage • Ethylene treatment stimulates production of ACC and ethylene Days @ 68°F (20°C) Ethylene Production during Ripening • More uniform softening • Enhanced production of flavor and aroma volatiles • Improved texture of fruit – buttery, not gritty – juicy Conditioning Pears for Ripening Cold Storage @ -1 to 0°C Ethylene @ 100 ppm, 20°C Bartlett Anjou & Bosc 2 to 3 wks. 6 to 8 wks. 1 to 2 days 1 to 3 days Pink End or Premature Ripening of Pears • • • • Fruit soften prematurely in storage Calyx is pink at harvest May be soft at blossom end on tree Cool temperatures just before harvest – May begin to satisfy the cold storage requirement for ripening 10 Effect of Storage Temperature on Pear Quality Pear Storage • Up to 3 months in regular cold storage – -1ºC -1ºC Lake County 8/23 10 weeks Storage • Controlled atmosphere storage – Recommended concentrations vary with variety – Susceptibility to CO2 injury increases with 2 maturity -1 -0.5 0.5 1 2°C Effect of Storage Temperature on Bartlett Pear Core Breakdown After Storage and Ripening Storage Storage Temp. °C (°F) Temp. °C (°F) -1 (30) -1 (30) Core Breakdown Core Breakdown Core Breakdown (%) (%) 0 0 40 40 56 56 0 (32) 0 (32) 3 (38) 3 (38) Blanpied, 1977 Effect of Delays in Cold Storage on Pear Quality Cold Storage at 1°C (33 °F) 0 1 2 3 4 DAYS DELAY 5 11 Effects of Temperature and Ethylene on Bartlett Pears 2°C (36 F) Harvested 8/2/2001 Stored 3 months -1°C (30 F) 0 ppm 0 ppm 1 ppm 1 ppm Effect of Ethylene on Internal Breakdown of Pears after Three Months Storage Fruit with Int. Breakdown (%) Benefits of CA Storage • Delays fruit ripening and senescence ♦ ♦ ♦ ♦ ♦ ♦ 30oF 100 80 60 40 20 0 control 1ppm 5ppm 10ppm 36oF softening yellowing scald development • Extends storage life 1 2 3 Harvest 1 2 3 Benefits of Controlled Atmosphere Storage Benefits of Six Months of CA Storage of Early Harvested Pears 6 months in Air 6 months in 2% O2 Air 1% CO2 + 2% O2 KMnO4 5% CO2 + 2% O2 KMnO4 12 Late Harvest 3 Months at -1°C Late Harvest 3 Months at -1°C 5% CO2 + 2% O2 KMnO4 Firmness of Pears Treated with 1-MCP upon Removal from Storage 1-MCP 20 Incidence of scald on ripened pears treated with 1-MCP 11-MCP 100 % Fruit with Scald 80 60 40 20 0 control 0.01ppm 0.1ppm 0.5ppm 1.0ppm Firmness (lb) 18 16 14 control 0.01ppm 0.1ppm 0.5ppm 1.0ppm 12 0 6 12 Weeks Stored 18 24 0 3 6 9 12 15 18 21 24 Weeks Stored at 30oF (+0-8 days at 68oF) Loss of 1-MCP Effect on Bartlett Pears During Storage Firmness (lbs) after 6 days at 20°C control 0.01 ppm 0.1 ppm 0.2 ppm 0.4 ppm 0.5 ppm 1.0 ppm Pear Postharvest Diseases • Opportunistic pathogens – wounds • Quiescent or latent infections • Spread by water systems – Grey mold rot (Botrytis cinerea) cinerea) – Blue mold rot (Penicillium expansum) expansum) – Bulls eye rot (Pezicula malicorticis) 15 10 5 0 0 1 2 3 4 Months at -1°C 5 6 13 Botrytis Rot Methods to Control Decay Pears and Apples • Low temperature storage • Controlled atmospheres • Fungicides – TBZ, not very effective-resistance effectiveeffective-resistance – New materials • Biological control – Yeasts or bacteria • Tree and fruit nutrition • Integrated approach – Nutrition, maturity, handling, sanitation, biological agents, heat, controlled atmosphere Biological Control Handling Damage Blue Mold then Yeast Blue Mold only • Bruising • Skin scuffing or vibration injury • Increases respiration rate • Increases water loss • Increases susceptibility to decay Yeast then Blue Mold Internal Bruising Injury Pear Injury during Packinghouse Handling 14 Reducing Skin Browning Bartlett Pears in the Market • Prevent injury to skin •Scuffing •brown spots •appearance could be improved!! – Phenolics and polyphenol oxidase enzyme mix and brown pigments result – Tight-fill packaging or air-ride trucks TightairTight-fill air-ride – Special packaging at retail • Antioxidant treatment – DPA or ethoxyquin reduce but do not eliminate damage symptoms 15 Changes in Hosui Pears Grown in New Zealand Seasonal Changes in Starch and Soluble Solids in Asian Pears TSS fructose sorbitol glucose Optimum Maturity for 3+ Months Storage and for Immediate Consumption for Nashi Varieties Long-Term LongStorage Variety Color Soluble Grade Solids Shinsui 2 13 Shinseiki 2 or 3 11 Kosui 4 Hosui 3 Nijisseiki 2 or 3 14 13 11 Immediate Consumption Color Soluble Grade Solids 4 or 5 14 4 or 5 12 4 or 5 4 or 5 4 or 5 14 14 12 sucrose Soluble Solids Pattern in Asian Pears 16 Relationship Between Harvest Maturity and Storage Disorders in Shinseiki after 12 Weeks at 0ºC 0º 0ºC Flesh Spot Decay (%) Color Grade 1 2 3 4 5 6 Slight 14 21 17 19 21 8 Severe 0 8 33 43 71 69 Core Browning (%) Slight 0 0 0 0 0 8 Severe 0 0 0 10 43 69 Watercore (%) Slight 0 0 0 5 21 0 Severe 0 0 0 0 0 15 Susceptibility of Five Nashi Varieties to Maturity-Related Storage Disorders MaturityMaturity-Related Flesh Spot Core Decay Browning Watercore Variety Shinsui Rare Rare Rare Shinseiki Hosui Nijisseiki High Slight High High Slight High High Slight High Controlled Atmosphere Storage of Asian Pears • Limited research (hint, hint) • Benefits are cultivar specific – 25% longer storage – Retain firmness – Delay changes in skin color • Oxygen – 1 to 3% for Nijisseiki – 3 to 5% for Ya Li • Carbon Dioxide – Less than 2% to avoid injury Response of 20th Century to Low O2 After 4 months at 0°C 0° 17 Carbon Dioxide Injury after 6 months @ 0°C 0° Internal Browning from Watercore after 6 months at 0°C 0° Hand Harvest into Small Padded Picking Bags Highly Susceptible to Bruising Carefully transfer to field bin!! Avoid bruising! 18 Field bins are loaded onto a trailer!! •Wooden bins may be lined with plastic to reduce abrasion •Better to keep bins on trailer from harvest to packing to avoid soil on bin Drenching bins of apples prior to storage •Diphenylamine -antioxidant to control scald •Fungicide •Calcium to control bitter pit Diphenylamine Staining Immersion of bins Apples naturally float Very gentle!! 19 Washing of Apples with Brushes and Detergent Wax Application Hand Sorting Remains Necessary Even with Electronic Sorting Electronic Sorting for Size and Color Optical Sizer Electronic Sorting for Size and Color Weight Sizer Tray Packing after Sizing 20 Automatic Bagging Generally Causes Bruising Pre-Sizing Apples Pre•Water systems to reduce damage •Sanitation can be an issue •Pre-sizing of fruit Preand return to bins 21 Bartlett pear trees can be very large! Remain productive for 100+ years! Harvest by hand into large soft-sided softpicking bags. Empty into field bins. Dumping fruit from field bin to packingline Immersion dump from field bin to packingline •bin pulled under water and fruit float out •need floatation salts •gentle •Combination wet/dry dump •Dry dump 22 Pre-Sizer to Remove Small Fruit Pre- Sorting Pears into Two Grades Center Lane for Canning and Juice Weight Sizer Computer determines the placement of fruit of various sizes Weight Sizer and Place Pack Operation Place Pack Operation Each fruit wrapped in tissue and placed in box in a pattern Rope Sizer •Not very accurate •Have mostly been replaced 23 Volume Fill Vibration Settling of Tight-Fill Box Vibration Tight- Strapping the Telescoping Box Closed Tray-Pack Box TrayCan Also Display in Box Future Research Needs? • CA conditions for asian pears • Effect of climate on pear physiology 24 ...
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This note was uploaded on 12/30/2010 for the course POM 212 taught by Professor Kadermitcham during the Spring '05 term at UC Davis.

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