Date of Award

Summer 8-10-2018

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Food Science and Human Nutrition

Advisor

Angela Myracle

Second Committee Member

Renae Moran

Third Committee Member

Lewis Perkins

Abstract

Prunus salicina, Japanese plums, and Prunus domestica, European plums, are naturally rich in fiber, minerals, vitamins and phytonutrients. Consuming plums can increase overall fruit intake and can be incorporated into part of a healthy diet. Through local plum production, harvesting can be completed without the need for cross-country shipping, which can increase overall acceptability and nutritional quality of the fruit. Furthermore, the increase in local production can help to boost Maine’s economy and creates a market for new plum product production.

The first objective of this study was to determine consumer acceptance of locally grown plum cultivars at a tree-ripened stage. Sensory testing was conducted in the Sensory Evaluation Center at the University of Maine on plum cultivars harvested at Highmoor Farm in Monmouth, ME. The highest rated cultivar for ‘overall’ acceptability was the Japanese plum, Oblinya, with an average rating of 7.27±1.42. Toka, Kahinta and Superior also had high ‘overall’ acceptability scores with average ratings of, 6.98±1.4, 6.97±1.55 and 6.9±1.37, respectively. European varieties Early Italian and Caselton also had high ‘overall’ acceptability ratings at 6.98±1.46 and 6.76±1.35, respectively. In a similar consumer study, fruit was believed to be accepted among consumers with likeness ratings of >5.0. All cultivars tested in this study outperformed this value.

The second objective of this study was to evaluate phytonutrient content of the plum cultivars. Phytochemical constituents were extracted using 80% acidified methanol for twelve locally grown plum cultivars at a tree-ripened stage. Total monomeric anthocyanin, total phenolics, and free radical scavenging ability was measured on the cultivars. The European plum Caselton had the highest anthocyanin content (1242.83±14.05mg /100 g.) Toka had the greatest antioxidant capacity, demonstrating 50% inhibition of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) (1.28±0.14 mg/mL.) Toka also had the highest total phenolic content (1006.04±21.88 mg/ 100g.) Statistically significant differences were found between Japanese and European varieties for total phenolic content and free radical scavenging ability, with Japanese cultivars having higher values in both categories.

Cold-hardy plum cultivars that can be produced in Maine were successfully cultivated and were widely accepted among consumers. Producing plums that are well liked by consumers provides a new agricultural sector for Maine’s farmers, in turn boosting local economies and creating a new market for processed plum products. The evaluation of consumer acceptance and bioanalysis of plum cultivars establishes a deeper understanding of novel, tasty, and healthy plums for producers to incorporate into their production programs. This study fills the gap in knowledge of cold-hardy cultivars, and demonstrates that tree-ripened cultivars Oblinya, Toka, Kahinta, Superior and Early Italian all have favorable marketing potential for tree-fruit farmers in Maine.

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