The Application of Qualitative and Quantitative Research to Evaluate Whole Wheat Bread and Sweet Whey Powder.

JERVIS, MATTHEW GABRIEL. The Application of Qualitative and Quantitative Research to Evaluate Whole Wheat Bread and Sweet Whey Powder. (Under the direction of Dr. MaryAnne Drake). Both qualitative and quantitative data collection methods hold great importance in the research of food products and consumer perception. Qualitative research can be used to understand consumer behavior and motivation, or to develop a hypothesis and relies on nonquantifiable data. Quantitative research can be used to test a hypothesis and involves a strictly objective measurement of variables of interest. Two studies were designed to explore the use of these two diverse data collection techniques. The first study was designed to determine children’s perceptions and attitudes towards whole grain sliced sandwich breads to identify ideal whole grain breads for children. Focus groups, emotional response surveys, appearance liking surveys, and an adaptive choice based conjoint survey were conducted with children (n=173). From focus groups, children had an overall positive attitude towards breads, but darker colored breads, and breads with toppings and crumb particulates were disliked. Quantitative utility values from conjoint survey analysis confirmed that across elementary, middle and high school aged children, children preferred bread with a light crumb (inside of the bread), a light crust, and no topping or added textures or visual cues in the crumb. A soft crust with no topping, and a soft crumb with no crumb particles or flake crumb particles were also preferred. Children had a generally negative feeling for breads with dark colored crumb and crust, but generally positive feelings for breads with light colored crumb and crust. Breads with white crumb were liked more than bread with dark crumb, regardless of crumb particles, crust or crust topping, and regardless of crumb color, no topping was preferred to flakes or oats as a topping to the loaf or slice of bread. These results demonstrated that children like soft breads with light colored crumb and crust with no fillings or toppings. Successful whole grain breads for children must have the visual appeal of a white bread. The second study was designed to understand the impact that point of bleaching had on the flavor and bleaching efficacy of various bleaching agents on sweet whey powder (SWP). Colored Cheddar whey was manufactured, fat separated and pasteurized. Subsequently, the whey (6.7% solids) was bleached, concentrated using reverse osmosis (RO) to 14% solids and then spray-dried, or whey was concentrated prior to bleaching and then spray dried. Bleaching treatments included: Control (CR) (no bleaching, 50°C, 60 min), hydrogen peroxide (HP) (250 mg/kg, 50°C, 60 min), benzoyl peroxide (BP) (50 mg/kg, 50°C, 60 min), lactoperoxidase (LP) (HP 20 mg/kg, 50°C, 30 min), and external peroxidase (EP) (2 dairy bleaching units (DBLU)/ml, 50°C, 30 min). The experiment was repeated in triplicate. Sensory properties and volatile compounds of SWP were evaluated by a trained panel and gas chromatography mass spectrometry, respectively. Bleaching efficacy (norbixin destruction) and benzoic acid levels were measured using high performance liquid chromatography. Differences in bleaching efficacy, sensory and volatile compound profiles and benzoic acid were observed with different bleaching agents (p<0.05), consistent with previous studies. Solids concentration impacted bleaching efficacy of HP (p<0.05) but not other bleaching agents. SWP from whey bleached with HP or LP following RO had increased cardboard and fatty flavors and higher concentrations of lipid oxidation compounds compared to SWP from whey bleached prior to RO. SWP bleached with BP after RO contained less benzoic acid than SWP from whey bleached before RO (p<0.05). Results indicated that solids concentration impacted bleaching efficacy of HP, and influenced off flavors and residual benzoic acid levels in SWP.