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Two harvest seasons: 2001 and 2002. Physical and chemical evaluation ... Beach plum samples provided by Richard Uva from different locations in the Northeast ...
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Slide 1:Fruit Quality of Beach Plum Samples Grown in the Northeast
Slide 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)
Slide 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
Slide 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
Slide 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
Slide 6: Methods
Soluble solids: °Brix Fruit size: width, height, depth % pulp: manual pitting with a cherry pitter
Slide 7:Method-Extraction
For chemical analysis, compounds extracted from the fruit Procedure followed based on Kalt et al. method (2001), with modifications
Slide 8:Method - Extraction
Slide 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
Slide 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
Slide 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
Slide 12:Photochem diagram
Slide 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.
Slide 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
Slide 15:Beach PlumData shown by farm within the state
Slide 16:Acid Content
Slide 17:Soluble Solids
Pulp ContentSlide 19:Fruit Size: Width
Slide 20:Total Phenols
Slide 21:Antioxidant Capacity
Slide 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.
Slide 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.
Slide 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.
Slide 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