1. Use of a Chlorophyll Fluorescence Detector to Monitor Grape Dehydration

2. Agriculture and Agriculture et Agri-Food CanadaAgroalimentaireCanada Ali A Ramin, Robert K. Prange and John M. DeLong Atlantic Food and Horticulture Research Centre Kentville, Nova Scotia, Canada

3. 1.Introduction to chlorophyll fluorescence (CF) - CF curve – Fo, Fm, Fv = Fm-Fo - identification of Fo as most important 2. Design of the HarvestWatch system - produces F α as an estimate of Fo - important features of HarvestWatch system 3. Applications of HarvestWatch system - control O 2 in CA stores - monitor water loss in fruit, e.g. grapes 4. Concluding Remarks

4. 1. Introduction to chlorophyll fluorescence (CF) - CF curve – Fo, Fm, Fv = Fm-Fo - Identification of Fo as most important 2. Design of the HarvestWatch system - Produces Fα as an estimate of Fo - Important features of HarvestWatch system 3. Applications of HarvestWatch system - Control O 2 in CA stores - Monitor water loss in fruit, e.g. grapes 4. Concluding Remarks

5.  Fluorescence (red) is at ca. 740 nm (far-red)  Known since the 1930’s

6. Fo Typical Chlorophyll Fluorescence Curve Fo changes in response to stress 0.2 sec Add modulating light (LED) Add saturating light

7. 1. Introduction to chlorophyll fluorescence (CF) - CF curve – Fo, Fm, Fv = Fm-Fo - Identification of Fo as most important 2. Design of the HarvestWatch system - Produces Fα as an estimate of Fo - Important features of HarvestWatch system 3. Applications of HarvestWatch system - Control O 2 in CA stores - Monitor water loss in fruit, e.g. grapes 4. Concluding Remarks

8. Output Scans Hub Sensors System PC with HarvestWatch Software HarvestWatch System components Sensor in Apple Storage

9. Fluorescence vs. Photon flux

10. Typical Fluorescence Scans (Healthy Product) F  (Fo at zero irradiance) does not change F  values

11. Typical Fluorescence Scans (Stressed Product) F  (Fo at zero irradiance) changes F  values

12. Features of HarvestWatch System  Durable – no moving parts  Single initial cost  Easy to install  Continuous measurement – 24 h/day  Very sensitive to small changes in Fα  Tech. Support - Isolcell  Res. Support – Ag. & Agri-Food Canada  Covers large surface area

13. 1. Introduction to chlorophyll fluorescence (CF) - CF curve – Fo, Fm, Fv = Fm-Fo - Identification of Fo as most important 2. Design of the HarvestWatch system - Produces Fα as an estimate of Fo - Important features of HarvestWatch system 3. Applications of HarvestWatch system - Control O 2 in CA stores - Monitor water loss in fruit, e.g. grapes 4. Concluding Remarks

14. “specific O 2 concentrations at which Fo suddenly increases”

15. Experimentation Chlorophyll-containing fruits and vegetables Fruit - apple, pear, banana, kiwifruit, mango, avocado Vegetables - cabbage, green pepper, iceberg lettuce, romaine lettuce Apple PearCabbage

16. Treatments 1. ambient O 2 2. programmed rapid decrease in O 2 Responses simultaneous O 2 and F  values Sample JarsCA Jar and Sensor unit

17. Low Oxygen Stress (Apple)

18. Low Oxygen Stress (Pear)

19. Low Oxygen Stress (Cabbage)

20. Other Stresses Detected by F  High CO 2 e.g. Cabbage Monitoring water loss

21. Monitoring Water Loss F  declines, e.g. in grape berries Postharvest: Preharvest (field): New Fluorescence Induction and Relaxation (FIRe) system may be better choice than HarvestWatch (See following slides)

22. Lid with HarvestWatch Sensor and 4 LED’s Sensor LED Base with grapes Postharvest Water Loss in Grapes

23. Change over 13 days in Control and Drying treatment Fα values for ‘Thompson’ and ‘Flame’ grapes. Control Fα Drying treatment Fα

24. ‘Thompson’ Fα and weight loss (expressed in proportion to the initial value) over 13 days. The estimated weight loss value is a mean of three groups of grapes. Weight loss Fα ‘Thompson’ grape

25. Comparison of weight loss changes and Fα changes in ‘Thompson’ grapes, using data from previous Fig. 0.80 = 20% wt. loss ‘Thompson’ grape

26. ‘Flame’ Fα and weight loss (expressed in proportion to the initial value) over 13 days. The estimated weight loss value is a mean of three groups of grapes. Weight loss Fα ‘Flame’ grape

27. Comparison of weight loss changes and Fα changes in ‘Flame’ grapes, using data from previous Fig. 0.80 = 20% wt. loss ‘Flame’ grape

28. CultivarTreatmentSSC (%) Tit. Acidity (mg/100 ml) pH ThompsonInitial18.27683.06 13 d drying23.711303.03 Control (13 d in cold room) 15.37903.16 FlameInitial19.65163.08 13 d drying25.57003.10 Control (13 d in cold room) 17.85443.33 CultivarTreatmentSSC (%) Tit. Acidity (mg/100 ml) pH ThompsonInitial 13 d drying Control (13 d in cold room) FlameInitial 13 d drying Control (13 d in cold room)

29. CultivarTreatmentSSC (%) Tit. Acidity (mg/100 ml) pH ThompsonInitial18.27683.06 13 d drying23.711303.03 Control (13 d in cold room) 15.37903.16 FlameInitial19.65163.08 13 d drying25.57003.10 Control (13 d in cold room) 17.85443.33 CultivarTreatmentSSC (%) Tit. Acidity (mg/100 ml) pH ThompsonInitial18.2 13 d drying23.7 Control (13 d in cold room) 15.3 FlameInitial19.6 13 d drying25.5 Control (13 d in cold room) 17.8

30. CultivarTreatmentSSC (%) Tit. Acidity (mg/100 ml) pH ThompsonInitial18.27683.06 13 d drying23.711303.03 Control (13 d in cold room) 15.37903.16 FlameInitial19.65163.08 13 d drying25.57003.10 Control (13 d in cold room) 17.85443.33 CultivarTreatmentSSC (%) Tit. Acidity (mg/100 ml) pH ThompsonInitial18.2768 13 d drying23.71130 Control (13 d in cold room) 15.3790 FlameInitial19.6516 13 d drying25.5700 Control (13 d in cold room) 17.8544

31. CultivarTreatmentSSC (%) Tit. Acidity (mg/100 ml) pH ThompsonInitial18.27683.06 13 d drying23.711303.03 Control (13 d in cold room) 15.37903.16 FlameInitial19.65163.08 13 d drying25.57003.10 Control (13 d in cold room) 17.85443.33

32. 1. Introduction to chlorophyll fluorescence (CF) - CF curve – Fo, Fm, Fv = Fm-Fo - Identification of Fo as most important 2. Design of the HarvestWatch system - Produces Fα as an estimate of Fo - Important features of HarvestWatch system 3. Applications of HarvestWatch system - Control O 2 in CA stores - Monitor water loss in fruit, e.g. grapes 4. Concluding Remarks

33. Concluding Remarks F  is an estimate of Fo at zero irradiance F  is very sensitive to water loss in grapes Change in F  stops at ca. 20-25% water loss Changes in water loss in the field may be measurable by new FIRe fluorescence system Continuous and non-destructive F  declines with water loss whereas it increases in low O 2