Storage of Fruit and Nut Crops

Storage of Fruit and Nut Crops Post Harvest Physiology and Storage www.Hortilover.com

Fresh Fruit and Nuts are Alive! HORT 319 - Temperate Fruit and Nut Production

Consume O2 Substrates Evolve CO2 Heat Ethylene Lose H2O through epidermis Metabolically active Tissue softening Starch to sugars Sorbitol to fructose Organic acids decreasing Flavor volatiles increasing Color changes Fruits and Nuts are Living HORT 319 - Temperate Fruit and Nut Production

Fresh fruit and nuts Minimize these changes Extend the life span of the fruit/nut Processed fruit/nuts Kill the fruit/nut Sterilize to avoid spoiling Extend time of edible state Objective of Storage HORT 319 - Temperate Fruit and Nut Production

Climacteric Apples Pears Apricot Peach Plum Fig Persimmon Non-climacteric Blueberries Grapes Cherries Strawberries Sweet oranges Lemons Types of Fruit HORT 319 - Temperate Fruit and Nut Production

Respiration increases during ripening Cell division Bloom Cell enlargement Maturation Ripening Senescence Types of FruitClimacteric vs. Non-climacteric Fruit Growth Respiration Climacteric Respiration Non-climacteric HORT 319 - Temperate Fruit and Nut Production

Ethylene content higher and increases more during ripening Cell division Bloom Cell enlargement Maturation Ripening Senescence Types of FruitClimacteric vs. Non-climacteric Fruit Growth Ethylene Climacteric Ethylene Non-climacteric HORT 319 - Temperate Fruit and Nut Production

Fruit Respiration in Response to Ethylene Rate dependent response to ethylene Amount of ethylene dictates the ultimate level of response HORT 319 - Temperate Fruit and Nut Production

Fruit Respiration in Response to Ethylene Non-rate dependent React to a threshold level to give about same response HORT 319 - Temperate Fruit and Nut Production

Climacteric fruit Increased respiration at ripening Ripen faster Ethylene Produce more Higher internal level Level increases at ripening Applied Ethylene Respond to applied ethylene in non-rate dependent fashion Non-climacteric fruit No increase in respiration Ripen slower Ethylene Produce less Lower internal levels No increase at ripening Applied Ethylene Rate dependent response HORT 319 - Temperate Fruit and Nut Production

Apples 3-10 months 40% stored Pears 2-7 months Grapes 2-3 months Nuts 1-4 years Stone fruit 2-8 weeks Berries 1-2 weeks Strawberry 1-5 days Fig 2-3 weeks Storage of Fresh Fruit - Crops HORT 319 - Temperate Fruit and Nut Production

Temperature Lowers All enzymatic processes Respiration Reduce microbial growth Sensitivity to ethylene Optimal temperature Above tissue freezing point -2ºC to 0ºC Important to remove field heat quickly Methods of StorageRefrigeration HORT 319 - Temperate Fruit and Nut Production

Humidity 97% RH = fruit does not lose moisture 95% RH = microbial growth favored 90% RH = poor microbial growth Loss of moisture Less product 5% = shrivelling Fruit is water in an expensive package Prevention 90% RH Wax coatings Shrink wraps Methods of StorageRefrigeration HORT 319 - Temperate Fruit and Nut Production

Examples Burying apples Film wraps Chemical packages to absorb ethylene Not closely controlled How does it work? Temperature Humidity Control of atmospheric gases CO2 O2 Ethylene Methods of StorageModified Atmosphere Storage HORT 319 - Temperate Fruit and Nut Production

CA storage Control Temperature/humidity Oxygen Carbon dioxide Ethylene For long term storage Methods of StorageControlled Atmosphere Storage HORT 319 - Temperate Fruit and Nut Production

Oxygen Level Lower to 3% from 21% Reduce respiration Reduce ethylene production If too low Anaerobic metabolism Off flavors Carbon dioxide Level Increase to 5% from 0.03% Reduce respiration Reduce ethylene production Inhibit the breakdown of pectic substances If too high Anaerobic metabolism Off flavors Methods of StorageCA Storage of Apples HORT 319 - Temperate Fruit and Nut Production

Ethylene Level “One bad apple spoils the whole barrel” Ripe/damaged fruit Release ethylene Induce other fruit to ripen Decrease sensitivity Lower temperatures Increase CO2 Decrease O2 Reduce levels Air ventilation Electric fork lifts Separate ripe from unripe fruit Remove ethylene via potassium permanganate Methods of StorageCA Storage of Apples HORT 319 - Temperate Fruit and Nut Production

Most important storage disorder in apples Dark brown, slightly depressed Caused by volatiles from the fruit Control Air circulation Antioxidants in post harvest dip Do not store susceptible varieties Post Harvest DisordersSuperficial Scald HORT 319 - Temperate Fruit and Nut Production

Translucent areas in the flesh Can be induced by excessive heat More common in over mature fruit Post Harvest DisordersWater core HORT 319 - Temperate Fruit and Nut Production

Bitter pit Sunburn Cork spot Cracking Post Harvest DisordersCalcium-related Disorders HORT 319 - Temperate Fruit and Nut Production

Role of calcium Functions in plant Regulate cell division Regulate nitrogen metabolism Important component of cell wall Not mobile in plant Moves slowly in soil Compete with Mg and K for uptake Worse under high temperature conditions Control: Calcium applications to the fruit Post Harvest DisordersCalcium-related Disorders HORT 319 - Temperate Fruit and Nut Production

Bitter pit Impairment of selective permeability of cell membranes Cell injury and necrosis Browning begins internally Develops external blemishes Sunburn Direct sun exposure Fruit tissue loses water Cell collapses Tissue under skin collapses Post Harvest DisordersCalcium-related Disorders HORT 319 - Temperate Fruit and Nut Production

Deep cracking Cell walls become thick and lose elasticity Fruit crack after rain or irrigation Cork spot After cell division cortical cells form additional cell walls within original cell Tissue hardens, ruptures, and browns Post Harvest DisordersCalcium-related Disorders HORT 319 - Temperate Fruit and Nut Production

HORT 319 - Temperate Fruit and Nut Production

Storage of Fruit and Nut Crops