Fruit Quality of Beach Plum Samples Grown in the Northeast

1. Fruit Quality of Beach Plum Samples Grown in the Northeast

2. Objectives • To evaluate fruit quality and field variation • To evaluate differences in total phenolic content (important for flavor) • To measure antioxidant capacity(important for marketing)

3. Experimental Design • 35 fruit samples from 4 different states (MA, NJ, NY, DE), 11 locations, wild and cultivated • Two harvest seasons: 2001 and 2002 • Physical and chemical evaluation

4. Materials • Beach plum samples provided by Richard Uva from different locations in the Northeast including cultivated samples from Falmouth, MA • Fresh fruits were analyzed for quality upon receiving • Stored at -40oC for further chemical analysis

5. Methods Fruit quality analysis • Fruit color: Hunter colorimeter, color values ‘L’ (lightness), ‘a’ (red to green), and ‘b’ (yellow to blue) • pH: pH meter • Acid: % citric acid

6. Methods • Soluble solids: °Brix • Fruit size: width, height, depth • % pulp: manual pitting with a cherry pitter

7. Method-Extraction • For chemical analysis, compounds extracted from the fruit • Procedure followed based on Kalt et al. method (2001), with modifications

8. Method - Extraction

9. Method – Chemical Analysis • Total phenolic content measured using Folin Ciocalteu reagent (Singleton and Rossi, 1965) • Gallic acid used as standard, absorbance read at 750 nm, results expressed as mg of gallic acid equivalents per 100 g of fruit

10. Method – Chemical Analysis Cont. • Antioxidant capacity of water soluble compounds (ACW) measured using photochemiluminometer (PHOTOCHEM) • The PHOTOCHEM uses a photochemiluminescence detection method • Free radicals are generated with a photosensitizer and react with luminol to produce light, which is measured quantitatively

11. Method – Chemical Analysis Cont. • The intensity of the photochemiluminescence is attenuated as a function of antioxidant concentration • Ascorbic acid used as standard, results expressed as equivalents of ascorbic acid in mg/100 g of fruit

12. Photochem diagram

13. Results • Large variations per location in all the measurements. • pH values ranged from 3.13 to 4.09. • Size: only width will be presented, the other 2 values followed the same pattern. • Color data not shown.

14. Results - reference • Commercial plum varieties- used for fresh consumption or for prune making • Soluble solids 12.8 - 29% • Total phenols 111 mg/100 g fruit • Acids approx. 0.5 g/100 g fruit

15. Beach PlumData shown by farm within the state

16. Acid Content

17. Soluble Solids

18. Pulp Content

19. Fruit Size: Width

20. Total Phenols

21. Antioxidant Capacity

22. Results • Cultivated samples from MA had the highest acidity. • A few samples had high Brix, lower acidity and relatively low phenol content. Potential for fresh market or minimally processed foods due to milder flavor. • Two samples had high phenol content, high antioxidant capacity, small size and low percentage pulp. Most phenolic compounds on skin.

23. Conclusions • Location (state and farm) and production practice did not seem to determine the fruit composition. 2002 harvest will provide confirmation. • Beach plum has significantly higher phenolic content than typical commercial varieties. Antioxidant capacity is likely to be also higher.

24. Conclusions • The high phenolic content and high acidity restrict the use of the fruit to processed products where blending and dilution are used to counteract the effect. • Another phase of the project involves working with chefs to develop specialty products.

25. Works Cited • Singleton, V. L.; Rossi, J. A., Jr. Colorimetry of total phenolics with phosphomolybdic- phosphotungstic acid reagents. Am. J. Enol. Vitic. 1965, 16, 144-158 • Kalt, W.; Ryan D. A. J.; Duy, J. C.; Prior, R. L.; Ehlenfeldt, M. K.; Kloet, S. P. V. Interspecific Variation in Anthocyanins, Phenolics, and Antioxidant Capacity among Genotypes of Highbush and Lowbush Blueberries (Vaccinium Section cyanococcus spp.). J. Agric. Food Chem. 2001, 49, 4761-4767