We re handling living products! The Importance of Temperature RESPIRATION. Page 1

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1 The Importance of Michael Reid Postharvest Short Course June 213 We re handling living products! Perishable products are alive Plant tissues are composed of cells Each cell is a minute factory carrying out thousands of tasks simultaneously The biological factory uses energy RESPIRATION Energy is produced through combustion of sugars, which produces CO2 The combustion of sugars is called respiration The process uses oxygen and produces CO 2 and energy C 6 H 12 O 6 + 6O 2 = 6 CO H 2 O We can determine the rate of development and aging by measuring the rate of CO 2 production Like determining activity in a factory by watching the smoke-stacks Page 1 1

2 Relative Perishability Nuts Dates Citrus Garlic Potato Apple Carrot Onion Banana Tomato Peach Artichoke Broccoli Strawberry Asparagus Peas Sweet Corn 1 - why is it important? Rate of deterioration rate of respiration Faster respiration, shorter life Respiration increases exponentially with T ml CO2 / kg hr y = e.847x R 2 =.9936 Relative Respiration Rate temperature (C) effects on product life As temperature increases, the rate of deterioration increases exponentially For every 1 C increase in temperature, the rate of deterioration increases 2-3 fold This increase is described by the Q1 - the ratio of respiration at temperature T + 1 to that at temperature T High temperatures also accelerate water loss, disease growth, appearance of disorders, and unwanted growth of plant parts Effects of Q 1 Example Strawberries How long do they last at room temperature? Q 1 (2 1) = 2 Life at 1 C? Q 1 (1 ) = 3 Life at C? We can store strawberries for two weeks at C (if we control Botrytis) Page 2 2

3 also affects other factors that are important to product life Ethylene Production Response Water loss Wound response Disease Unintended growth What is the correct temperature? Species from cool climates 3 C Species from tropical climates 1 1 C Species from sub-tropical climates Varies Avocados 1 C Kiwi - C Stored for 1 week The real world Box 2 Roses arriving in the Netherlands from Kenya, by air! 3 Transport time (h) : 9/12/24 3:2 9/13/24 9/13/24 /11/24 :4 22: Storage experiments First Red Roses Page 3 3

4 Narcissus & respiration Narcissus Respiration & Vase life Respiration (ml CO2/kg/hr) y = e.1378x R 2 = (C) Days vase life y = -.314x R 2 = Respiration at storage temperature (ml CO2/kg/hr) Shelf-life model Based on respiration regressions By species or cultivar Predicts remaining vase life Flowers lose vaselife even under good temperature management % Vaselife Insert graph of flower life Time (hr) % vaselife remaining % Vaselife Time (hr) % vaselife remaining Not just flowers Monitoring tools Dataloggers Time/temperature labels Active RFID Page 4 4

5 This image cannot currently be displayed. This image cannot currently be displayed. Time/temperature labels A new tool - active RFID tags Change time, Avery label (h) y = e -.13x 2 R 2 = Radio Frequency Identification Chip Antenna receives and transmits information in RF signals Passive chips already in widespread use (Walmart) Active tags include battery Environmental sensors Battery Assisted RFID Tag Long range identification Data tracking Time/temperature monitoring Sensor monitoring Pilot Study 11 wholesalers sent tags to 48 domestic and offshore growers At the time of packing, the tags were, placed into the flower boxes, which were shipped to the wholesalers The tags provided transit time and temperature data Our respiration/temperature model was used to calculate remaining vase life Results Average transit time days Minimum 1 day (air from CA) Maximum 12 days (sea from Colombia) Average temperature 1 C Lowest - 2 C Highest 3 C! Average vase life loss 14% Maximum 41% Minimum 3% Questions? Page