Date of Award

12-2004

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

Denise Skonberg

Third Committee Member

Alfred Bushway

Abstract

Maine wild (lowbush) blueberries (Vaccinium angustifolium Ait.) are a unique natural resource. The high antioxidant activity of this fruit crop is thought to have an important role in both the prevention and treatment of cardiovascular disease, cancer, and other chronic diseases. Dietary consumption of soy protein also has been shown to have many health benefits. The objectives of this study were to develop new soy beverage products that utilize Maine blueberries and to evaluate their physical, chemical, and sensory properties. There were four beverage formulations and soy protein ingredient was either a 90% soy protein isolate or a 44% soymilk powder. The quantity of soy protein used was based on the FDA health claim requirement of 6.25 g soy protein per serving. The sweetener added to each formulation was either 8.0% brown rice syrup or a 16% 1: 1 mixture of apple and white grape juice concentrates. Blueberry juice concentrate levels were 12% in all formulations. All formulations underwent HTST pasteurization. Mean anthocyanin pigment content of the pasteurized beverages ranged from 29.1 - 38.6 mg/100 g of beverage. Mean total phenolic compound content ranged from 496.6- 664.0 mg/100 g of beverage. Mean antioxidant activity of the pasteurized beverages ranged from 2488.8-3322.8 μmol TE/100 g. Phenolic content was strongly correlated with antioxidant activity (r = 0.84). Beverage formulations were evaluated by 10 trained descriptive panelists and a consumer panel. The isolate juice concentrate beverage (IJC) had more blueberry flavor than did the other beverages. The beverages containing juice concentrates as a sweetener were rated sweeter than the beverages that contained brown rice syrup. The panelists rated the formulations containing rice syrup as having more bitter flavor. Beverages containing soymilk powder had higher ratings for painty aroma and nutty flavor. There were 68 consumers who evaluated the beverages in an acceptability study. Beverages were evaluated for color, flavor, mouthfeel, and overall acceptability using a 9-point hedonic scale. Consumers found the dark violet color of the beverages acceptable, with all four formulations receiving a mean score of at least a 6.0 ("like slightly") on the hedonic scale. The isolate juice concentrate beverage (IJC) received the highest mean score for flavor, mouthfeel, and overall acceptability; mean scores for all attributes ranged from 6.0 ("like slightly") to 7.0 ("like moderately"). With the exception of the attribute color, the mean overall acceptability scores for the other formulations ranged from 4.0 ("dislike slightly") to 5.0 ("neither like nor dislike"). Overall acceptability of the beverages was most strongly correlated with flavor (r = 0.91). There was also a strong correlation (r = 0.77) between mouthfeel and overall acceptability. The results of this study will be used to create new markets for Maine blueberries. Combining Maine blueberries with soy protein in a new beverage product has marketing potential. Increasing the demand for Maine's blueberry crop will help growers and processors in the industry as well as aid the State of Maine's economy.

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