Date of Award

Spring 5-13-2017

Level of Access

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Food Science and Human Nutrition

Advisor

Mary Ellen Camire

Second Committee Member

Gregory Porter

Third Committee Member

Denise Skonberg

Abstract

The potato (Solanum tuberosum L.) is an important vegetable in human diets. In the United States, the potato is the most consumed vegetable. Potatoes contain many nutrients including potassium, vitamin C, and dietary fiber. However consumption of fresh potatoes has declined. The current study was conducted in two parts: 1) evaluation of purple-fleshed potato varieties (All Blue, Adirondack Blue, AF5375-3, AF5412-1, AF5412-3, and AF5414-1), and 2) a comparison of the industry standard Russet Burbank with two potato varieties (Easton and AF4296-3) bred for lower amounts of acrylamide formation during the French fry making process. The goals of the first study were to determine the phytochemical composition and evaluate key sensory characteristics of the potatoes after typical consumer cooking practices of steaming and roasting. The goal of the French fry study was to determine the sensory characteristics of French fries made from Russet Burbank, Easton, and AF4296-3 potatoes fertilized with varying amounts of nitrogen, and whether information regarding acrylamide content affects consumers’ liking of French fries made from these potatoes.

Steamed purple-fleshed potatoes had a high concentration of anthocyanins ranging from 24.03 to 51.06 mg cyanidin-3-glucoside (C3G)/100 g potato. Experimental variety AF5412-1 had the highest anthocyanin content (p ≤ 0.05). Roasting reduced anthocyanin content when compared to steamed potatoes, but had more than raw potatoes on a fresh weight basis. Roasted potatoes were higher in total free phenolics and antioxidant activity. Roasted Adirondack Blue contained the highest content of phenolic compounds at 220.89 mg chlorogenic acid eq/100 g potato, AF5375-3 was statistically similar. After roasting, Adirondack Blue, All Blue, and AF5375-3 had the highest antioxidant activity. No significant differences in liking were found among roasted potatoes (n = 48) for any attribute. Liking scores ranged from 6.3 to 7.2 on a nine-point hedonic scale over all categories. AF5412-1, AF5375-3, and AF5412-3 were liked most for color and appearance. Hedonic scores ranged from 6.1 to 7.7 for color, appearance, texture, flavor, and overall liking.

In the second part of this study, a 3 x 4 factorial design, three different varieties of potatoes (Russet Burbank, Easton, and AF4296-3) were fertilized with four levels of nitrogen (0, 45.3, 90.7, and 136.1 kg N/acre), to determine whether the degree of fertilization affected acrylamide production. Acceptability differences were not found by consumers (n = 48) between treatments for aroma, texture, flavor, and overall liking on a nine-point hedonic scale. Differences in color and appearance were found. Overall liking for Russet Burbank samples declined after the acrylamide content was revealed.

Consumer education may pave the way to greater acceptance of French fries that are lighter in color and lower in acrylamide content. While these findings provide important information for Maine’s potato industry, further research is needed.

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