Date of Award

5-2004

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Food Science and Human Nutrition

Advisor

Mary Ellen Camire

Second Committee Member

Alfred A. Bushway

Third Committee Member

Denise I. Skonberg

Abstract

Lowbush or wild blueberries (Vaccinium angustifolium Ait.) contain an unusual variety of flavonoid phytochemicals. High in antioxidant activity, these berries may offer protection against aging, inflammation and certain infections. Soy protein consumption also offers many health benefits, including reducing risk of coronary heart disease.

Since new commercial markets are needed for Maine wild blueberries, our objectives were to develop acceptable frozen desserts (similar to ice cream) and frozen bars containing both wild blueberries and soy protein, and to evaluate the effects of health information and consumer health attitudes on bar acceptability.

Four frozen dessert formulations were prepared with soy protein isolate and different amounts of blueberry concentrate and puree. The high fat formulation with 10% fat content and 8.6% blueberry concentrate received the highest acceptability with all attributes achieving scores >6.0 (p≤0.05). The four formulations had a mean overrun range 67% to 81%, anthocyanin content range of 20.95 - 47.75 mg/100g, antioxidant activity ranged from 1279 to 1910 TE/100g and total phenolics of 42.25 to 63.47 mg/100g. Over a third (35%) of the sensory panelists are trying to increase blueberry consumption, 20% want to increase their consumption of soy, and 20% would like to increase their consumption of both foods. The majority of panelists (88%) would like to see these frozen desserts in the market.

For the frozen bar formulations, three soy food ingredients: soy isolate, soymilk, and tofu were used. For the soymilk and tofu formulations, soy ingredients were mixed with sugar and water then coated with a mixture of blueberry juice concentrate, frozen wild blueberry puree, citric acid and guar gum, whilethe soy isolate formulation was a homogenized product. Each formulation had 6.25 grams of soy protein content. Forty-two panelists (19-63 years old; 19 male and 23 female) participated in two sequential sensory evalutation sessions. During the first session, consumers provided demographic information, the Health and Tast Attitude Scales (HTAS) and a blind evaluation of the frozen bars' acceptability using the 9-point hedonic scale. During the second session, consuemrs were randomly assigned to receive either no information or a brief overview of health benefits of soy and wild blueberries, prior to evaluating bars that were labeled with their soy content.

The frozen bars had a mean anthocyanin content range of 51.85 - 67.69 mg/100g, antioxidant activity ranged from 532 to 865 TE/100g and total phenolics of 41.43 to 76.89 mg/100g. The mean scores of overall acceptability in the tofu, soymilk, and soy isolate formulation were 4.7, 4.8, and 5.1, respectively. HTAS appeared to be a good tool for characterizing consumers' attitudes towards dietary patterns, when factor loadings were calculated within each sub-scale of both health and taste oriented questions. Nutrition information did not affect acceptability scores except for texture. Significant differences were observed between ratings given by male and female subjects.

This study suggests that consumers could accept blueberry soy frozen desserts. New markets for wild blueberries could benefit Maine growers and processors who are currently suffering from low blueberry prices and increased competition.

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