Date of Award

8-2005

Level of Access

Campus-Only Thesis

Degree Name

Master of Arts (MA)

Department

Food Science and Human Nutrition

Advisor

Mary Ellen Camire

Second Committee Member

Denise Sltonberg

Third Committee Member

Alfred Bushway

Abstract

The health benefits of blueberries (Vaccinium species) have been widely attributed to their antioxidant activity. Because of their antioxidant activity, consumption of these berries may offer protection against urinary tract infection, cancer, cholesterol and cardiovascular diseases, memory loss, age related diseases, and other health benefits. The objectives of this study were to develop an extruded confection product that would have some health benefits and utilize Maine wild blueberries, and blueberry byproducts. Another objective was to protect the loss of antioxidant activity after processing by adding rosemary extract. In the first study, three different formulations were prepared using different sources of blueberry liquids (blueberry juice concentrate, blueberry concentrated spent, and blueberry spent). All formulations were mixed with sugar (48.4%), starch (16.4%), flour (8.2%), and had the same amount of moisture (10.5%). The three different extrudates had anthocyanin content that ranged from 2.1 - 62.6 mg/100 g dry basis (DB), total phenolics ranged from 36.8 - 12 12.0 mg/100 g DB, expressed as ferulic acid equivalent, and antioxidant activity ranged from 100.9 - 2770.8 μmol Trolox equivalent/100g. All of these were significantly (p≤0.05) higher in the blueberry juice concentrate extrudate. In the second study, the effect of low (8.5%) and high (10.5%) moisture content formulations was evaluated. Blueberry juice concentrate was pumped in different amounts to achieve the desired moisture level. Moisture content significantly (p≤0.05) affected extrusion conditions; higher moisture reduced torque, die pressure, and melt temperature. The two extrudates had anthocyanin content that ranged from 62.6 - 79.8 mg/100g DB, total phenolics ranged from 1008.0 - 1212.0 mg/100g DB as ferulic acid equivalent, and antioxidant activity ranged from 2316.0 - 2770.8 μmol Trolox equivalent/100 g. In the third study, the effect of extrusion on blueberry juice concentrate fortified with rosemary extract (0.0, 0.1, and 0.3% v/v) was examined. The three different formulations were prepared by extruding them with the dry mix previously described. The three different extrudates had anthocyanin content that ranged from 62.6 - 99.3 mg/100g DB, total phenolics ranged from 998.3 - 12 12.0 mg/100 g DB as ferulic acid equivalent, and antioxidant activity ranged from 2770.8 - 2978.1 μmol Trolox equivalent/100g. Addition of rosemary extract minimized anthocyanin degradation and increased antioxidant activity. The mean scores of overall acceptability by consumers' evaluation of blueberry spent, blueberry concentrated spent, blueberry juice concentrate, and blueberry juice concentrate +0.3% RE extrudates were 4.2, 4.7, 6.5, and 6.4, respectively. These results suggest that consumers could accept a blueberry confection product made with blueberry juice concentrate once further refinements are made in the process. These preliminary studies indicate that extrusion decreases anthocyanins but retains sufficient antioxidant activity to warrant further studies.

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