Recipient Organization
NORTH CAROLINA STATE UNIV
(N/A)
RALEIGH,NC 27695
Performing Department
Food, Bioprocessing, and Nutrition Sciences
Non Technical Summary
A consistent high quality flavor is desired in fluid and cultured dairy products as well as in dried ingredients and cheese for finished product consistency in ingredient applications and palatability for direct consumption. Further, consistent quality and knowledge of how to maintain, produce or prevent particular flavors is desirable for marketing in conjunction with new consumer trends regarding environment and sustainability. Sensory quality and consumer market research are the critical determinants in identification of target consumers. This project will address these problems using a combination of sensory and instrumental approaches.
Animal Health Component
85%
Research Effort Categories
Basic
10%
Applied
85%
Developmental
5%
Goals / Objectives
A consistent high quality flavor is desired in fluid and cultured dairy products as well as in dried ingredients and cheese for finished product consistency in ingredient applications and palatability for direct consumption. Further, consistent quality and knowledge of how to maintain, produce or prevent particular flavors is desirable for marketing in conjunction with new consumer trends regarding environment and sustainability. Sensory quality and consumer market research are the critical determinants in identification of target consumers. The goal of this project will be to characterize and define sensory and chemical parameters of dairy foods and ingredients to generate healthy and nutritious foods that are appealing to consumers.Objective 1:To identify and quantify chemical flavor components responsible for specific flavor attributes in fluid milks and milk protein ingredients.Objective 2:To characterize and quantify chemical flavor components due to specific unit operations in dried dairy or plant ingredients, cheeses, or protein beverages.Objective 3: To characterize consumer perception of selected products and relate perception to quantifiable sensory or chemical measurements.
Project Methods
Objective 11. The dried ingredient flavor language and milk flavor language developed by PI Drake (Drake et al., 2003; Russell et al., 2006; Wright et al., 2009; McCarthy et al., 2017) are used to document flavor profiles of samples. A specific goal will be to determine the impact of various unit operations and storage on fluid milk and milk protein ingredient and fluid milk beverage flavors. Products are manufactured by industry collaborators or processed in the NCSU Creamery pilot plant.2. Flavor volatiles will be extracted from selected products by direct solvent extraction with high vacuum distillation , SPME and stir bar sorptive extraction (SBSE). Preliminary work in our laboratory on this objective has been initiated and successful trapping of volatile flavor components is achieved in this manner. Accurate quantitation will be accomplished by cool on-column injection with gas chromatography (GC)-mass spectrometric (MS) or triple quadrupole gas chromatography mass spectrometry (GC-MS/MS) analysis and use of internal standard methodology and compound class separation. Separation and analysis of flavor components will be conducted by GC-MS on two different stationary phases. GC-olfactometry (sniffing of GC effluent), will be used to indicate and compare potent odor-active compounds. In addition to evaluation of potent odorants by AEDA, multivariate statistical analysis including factor analysis and principal component analysis will also be used to identify and correlate key chemical components with specific sensory flavors. Evaluation of existing literature will also be conducted to aid in identification/clarification of potential chemical anchor compounds.Chemical compounds identified as potential chemical anchors will be evaluated qualitatively and quantitatively in model matrices. Compound(s) will be added to each matrix at the concentration(s) encountered in the dried ingredient exhibiting the flavor attribute.A trained sensory panel will evaluate the spiked models in blind studies (eg. the panel will not know what descriptor is being studied). Blind studies will ensure that a true indication of the sensory impact of the compound is addressed. When a compound or compounds have been identified by the sensory panel as associated with a particular flavor, threshold studies and the linear dose response behavior of the compound(s) in the milk matrix will be determined. GC-O and AEDA as well as previous literature from milk flavor analysis allow us to identify qualitative aspects and relative intensities of isolated aroma components, but do not indicate the sensory impact of chemical components in a milk matrix or the concentration range within which these components exhibit a significant impact. Identification of the linear dose response behavior of chemical components will enable clarification of the role a particular chemical component plays in milk flavor perception across a concentration range and will also result in identification of protocols for preparation of reference samples for panel training. Threshold studies of identified chemical reference components confirmed by descriptive analysis will be conducted by ascending forced choice trials using screened experienced panelists (n=25).Objective 21. Screening and identification of ingredients:Dried ingredients or commercial beverages containing elevated levels of specific flavor attributes for which chemical anchors have not been identified will be selected from commercial sources or manufactured in the NCSU pilot plant. These will be later subjected to exhaustive flavor composition analyses (explained below).2. Flavor analysis and characterization--identification/quantitation of key odorants:For each ingredient (pair or group) two methods for isolation of volatile compounds dynamic headspace-thermal desorption, and solvent extraction-high vacuum distillation will be applied. These are complementary methods that will allow us to sample the wide range of aroma compounds in the cheese--from highly volatile components to intermediate and semi-volatile components (Horwood, 1989; Zehentbauher and Reineccius, 2000). We will use standard addition methodology using 2-methyl-3-heptanone as internal standard. Solvent extraction (ether)-high vacuum distillation has been previous described (Milo and Reineccius, 1997; Suriyaphan et al., 2000). Separation and analysis of flavor components will be conducted by GC-MS on two different stationary phases (nonpolar DB5 and polar FFAP columns). GC-olfactometry (sniffing of GC effluent), including both GCO of decreasing headspace samples (GCO-H and GCO-DHS) and aroma extract dilution analysis (AEDA), will be used to indicate and compare (between ingredients) potent odor-active compounds. Evaluation of existing literature will also be conducted to aid in identification/clarification of potential chemical anchor compounds.Objective 3Survey approaches including but not limited to conjoint analysis, Kano questioning, and Maximum Differential scaling as well as traditional and non-traditional preference mapping techniques will be applied or developed to relate consumer perception to quantifiable sensory or instrumental analyses or to determine consumer attitudes and preferences to current key concepts (such as sustainability) as they relate to dairy foods or protein enriched foods. Category surveys will be conducted on some products. To conduct the category survey, a descriptive sensory panel will be trained to identify and quantify sensory properties (appearance, flavor, texture) of each product Panelists will be trained to identify and quantify sensory attributes (Meilgaard et al., 1999; Drake and Civille, 2003). Following language identification and scale usage, panelists will discuss products and the identified attributes for several training sessions. Analysis of data collected from training sessions will be used to confirm that the panel is operating in unison as an instrument and is ready for formal product analysis (Meilgaard et al., 1999).A minimum of 10-15 commercial products from each category will be collected. A large array of products is crucial as the survey and the sensory space defined is only as good as the samples that are collected and evaluated. Order of presentation will be balanced among panelists. Data will be analyzed by analysis of variance with means separation to determine specific differences between means and by principal component analysis to determine how all of the samples were differentiated from each other across all of the attributes. These results will be used to identify representative products for consumer testing and to merge with consumer results to characterize drivers of liking.Consumer acceptance testing will be conducted on representative products within each category. As with descriptive analysis, testing on each product category will be conducted separately. For each product type, 6 to 10 representative products will be selected for consumer testing Consumers will evaluate each product for flavor, texture, and overall acceptance on a nine-point hedonic scale (Lawless and Heymann, 1998; Meilgaard et al., 1999). Additionally, acceptance and intensity perception of other attributes will also be scaled. A minimum of 100 consumers will be recruited. Consumers will receive food treats and gift certificates for participation. Traditional preference mapping techniques will be applied to identify key drivers. Additionally other techniques to characterize consumer perception will also be evaluated including focus groups, qualitative multivariate analysis and non-traditional preference mapping.