1. Processing and Storage Effects on Berry Bioactives
Luke R. Howard, Ph.D .

2. Phytonutrient/Phytochemical
Components in a plant based diet other than traditional nutrients that can reduce the risk of degenerative diseases

3. Berries and Health Promotion
Prevention of Chronic Diseases CHD & stroke Cancer Neurological disorders Obesity Type II diabetes
Mechanisms Antioxidant Anti-inflammatory Cell signaling Gene regulation Apoptosis Modulation of enzymes

4. Free Radicals

5. Antioxidants

6. Fruit and Vegetable Phytochemicals
Fruit and vegetable phytochemicals play an important role in health-promotion
Due to limited shelf-life and seasonal availability, fruits and vegetables are commonly consumed in various processed forms
How does processing impact phytochemical content?

7. Flavonoids

8. Procyanidins
Epicatechin
Procyanidin B2

9. Anthocyanin-Procyanidin Polymers a.k.a Polymeric Pigments

10. The Problem
Phytochemicals losses are inevitable during fruit and vegetable processing
Losses are due a number of processing, biochemical, and food matrix factors
Losses can also occur during storage of processed products

11. Processing Factors Influencing the Stability of Phytonutrients
Temperature (blanching and pasteurization)
Light
Oxygen
Water (washing, soaking, canning)
Physical removal of tissues

12. Thermal Degradation of Anthocyanins

13. Strawberry Puree Stored One Month at 25oC

14. Biochemical Factors Influencing the Stability of Phytonutrients
Co-factors
Metals
Enzymes pH
Ascorbic acid

15. Consequences of Cell Disruption
PPO O2
PPO/POD
POD
+ o-diphenols
quinones
ACY
Phenolics
Organic acids
Sugars
ascorbic acid
degradation products
ACY
tannins + ACY
mediators?
polymers O2
tannins
ACY
tannins
polymers
ACY

16. pH Effect on Anthocyanin Structure

17. Food Matrix Factors Influencing the Stability of Phytonutrients
Chemical structure/solubility
Tissue localization: Free vs. bound
Interactions among compounds

18. Light Microscopy of Cranberry Pomace
Differential interference contrast (DIC) microscopy image of residue remaining after ground cranberry pomace was extracted with acetone:water:acetic acid (70:29.5:0.5) and stained with dimethylaminocinnamaldehyde (DMAC) at 20x magnification
Differential interference contrast (DIC) microscopy image of residue remaining after ground cranberry pomace was treated with 2 N NaOH at 60 °C for 15 m and stained with dimethylaminocinnamaldehyde (DMAC) at 20x magnification

19. Procyanidin Oligomer (DP1 – DP6) Composition of Cranberry Pomace Before and After Treatment with Sodium Hydroxide

20. Properties of Phytonutrients in Plant Tissues
Feature
Carotenoids
Phenolics
Subgroups
Lutein, α-carotene, β-carotene, zeaxanthin, β-cryptoxanthin
Phenolic acids, hydroxycinnamates, flavonoids
Solubility
Lipid
Water
Cellular localization
Associated with membrane protein, complexes in chloroplast or chromoplast
Dissolved in vacuole and apoplast, some may be cell wall bound (not water soluble)
Structural localization
Some types preferentially in surface tissues like peel and outer pericarp
Anthocyanins preferentially in peel; procyanidins in peel and seed; hydroxycinnamates in flesh, ellagitannins in seeds

21. Changes in Antioxidant Activity as Affected by Heating
Nicoli et al. (1999) Trends Food Sci. Tech. 10:94-100

22. Food Matrix Interactions – Anthocyanin Co-pigmentation
Intermolecular
copigmentation
Self-association
Metal complexation
Intramolecular
copigmentation
Aglycone
Sugar
Copigment
Acid

23. Food Matrix Interactions – Binding of Procyanidins to Cell Wall Polysaccharides
Le Bourvellec et al. (2009) Carbohydrate Polymers 75:

24. Food Matrix Interactions – Binding of Procyanidins to Proteins
Haslam (1998) Practical Polyphenolics: From structure to molecular recognition and physiological
action. Cambridge University Press

25. Case Study: Processing Effects on Blueberry Polyphenolics

26. Case Study I Objectives
To determine how different preservation methods (canning, pureeing, juicing) affect the retention of blueberry polyphenolics and antioxidant capacity
To determine how storage of processed products affects the retention of blueberry polyphenolics and antioxidant capacity

27. Fresh Blueberries (cv. Bluecrop)
Analysis of Fresh Berries
Frozen Berries
Individually Quick Frozen (IQF)
Puree
Juice
Canning
Baking
Canned (Syrup)
Canned (Water)
Clarified
Non-Clarified
Pie-Canned in Water
Pie-Frozen Berries
Sampling: 1 d, 1 mo, 3 mo, 6 mo

28. Juice Processing Steps

29. Chemical Analysis
Polyphenolics (anthocyanins, procyanidins, chlorogenic acid, flavonols) measured by HPLC
Antioxidant capacity: ORACFL assay
Polymeric color: Colorimetric assay, measures the amount of anthocyanin polymers

30. Polymeric Color Assay

31. Total Anthocyanin Retention and Polymeric Color in Blueberry Juices

32. Total Anthocyanin Retention and Polymeric Color in Canned Blueberries

33. Total Anthocyanin Retention in Blueberries Canned in Syrup

34. Total Anthocyanin Retention and Polymeric Color in Blueberry Puree

35. Total Flavonol Retention in Blueberry Juices

36. Total Flavonol Retention in Blueberries Canned in Syrup

37. Total Flavonol Retention in Blueberry Puree

38. Total Procyanidin Retention in Blueberry Juices

39. Total Procyanidin Retention in Blueberries Canned in Syrup

40. Total Procyanidin Retention in Blueberry Puree

41. Chlorogenic Acid Retention in Blueberry Juices

42. Chlorogenic Acid Retention in Blueberries Canned in Syrup

43. Chlorogenic Acid Retention in Blueberry Puree

44. ORACFL Retention in Blueberry Juices

45. ORACFL Retention in Canned Blueberries

46. ORACFL Retention in Blueberry Puree

47. Tissues Small intestine Liver Kidney Urine
Dietary polyphenols
Tissue
metabolites
Tissues
Small
intestine
Liver
bile
Kidney
Colon
Urine
Microbial
metabolites
Feces

48. Discussion
Which processing, biochemical, and food matrix factors most likely played a role in polyphenolic losses during processing and storage of blueberry products?
Why does the antioxidant capacity of stored products change little during storage despite losses of anthocyanins and procyanidins?

49. Discussion Continued
What steps can processors take to minimize phytonutrient losses during processing and storage?
What steps can consumers take to minimize phytonutrient losses following purchase of processed berry products?
Would you expect processed berry products to have the same health benefits as fresh berries?