Christy Alsado | ALES Graduate Seminar

Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree. This is an ALES PhD Final Exam Seminar by Christy Alsado. This seminar is open to the general public to attend.

Zoom Link: https://ualberta-ca.zoom.us/j/91858459546?pwd=G3iGM1CrFo1ebpkN33tJsw4M5dObEb.1 

PhD with Drs. Wendy Wismer and Lingyun Chen.    

Thesis Topic: Multi-dimensional characterization of plant-based and dairy milks: Sensory attributes, consumer perceptions, and tribo-rheological properties

Abstract:

Plant-based milk (PBM) has been viewed as a sustainable and healthier alternative to dairy milk (DM). However, differences in PBM composition lead to variations in physical properties, consequently affecting sensory properties, consumer acceptance, and perception. This research aimed to address current challenges by developing a fortified oat milk and comparing it with commercial PBMs and Dairy Milks (DMs) through sensory characterization, consumer perceptions, and instrumental analyses.

In the first study, oat milks were fortified with β-glucan at a level that attains health benefits and protein at a level equivalent to cow’s milk. Sensory attributes and liking were evaluated by consumers (n=106) using the 9-point hedonic scale, Just-About-Right, and Check-All-That-Apply (CATA). Fortification with β-glucan significantly increased the overall liking of oat milks attributed to smoothness. However, fortification with β-glucan and oat protein significantly reduced the overall liking due to rancid, chalky, and sandy attributes. Conjoint Analysis (CA) confirmed that protein from plant-based sources, protein content greater than cow’s milk, and β-glucan at recommended health-benefiting levels were the most important attributes to consumers. Thus, improving the protein component and sensory attributes was essential for greater acceptance of fortified oat milks.

The second study developed the fortified oat milk using β-glucan and pea protein, and determined the influence of extrinsic cues (labels, testing locations) on consumer perception and acceptance.  Consumers (n=108) evaluated fortified oat milks for four consecutive days: Day 1 (label pre-exposure) in sensory laboratory; Day 2-3 (bottles labeled with either health or environmental benefits) through Home-Use-Test (HUT); Day 4 (post-exposure) in sensory laboratory. Attribute intensity and overall liking (9-point hedonic scale) were evaluated daily, and wellness perception (six dimensions assessed by CATA items) was evaluated on Days 1 and 4. Fortified oat milks with health and environmental labels were correlated with a greater number of wellness dimensions compared to unlabelled milks, while product liking did not significantly differ between labeled and unlabeled milks. Additionally, testing locations did not significantly influence product liking and perceived attribute intensities in fortified oat milk. This implied that although extrinsic cues enhanced positive experience, consumers remained consistent in their liking for fortified oat milk, meriting comparison of fortified oat milk with a broader range of commercial PBMs and DMs.

In the third study, experienced sensory panelists (n=14) evaluated fortified oat milk, PBMs, and DMs (n=29) through Projective Mapping. Variations in textural attributes were perceived; moreover, six clusters revealed groups with similar texture profiles. Twelve milks were selected from these clusters for evaluation by consumers of both PBMs and DMs (n=109) using liking (9-point hedonic scale), sensory attributes (Rate-All-That-Apply), perceptions and uses (CATA), and dairy consumption motivation (4Ns Scale) based on factors ‘Natural,’ ‘Need,’ ‘Normal,’ and ‘Nice.’ Dairy and oat milks were most significantly liked, generating two consumer clusters: dairy-oat-highlikers (high liking for dairy and oat milk) and dairy-plant-modlikers (moderate liking for dairy and select plant-based milks). ‘Sweet,’ ‘smooth,’ and ‘creamy’ were the drivers of liking, while ‘simple,’ ‘traditional,’ ‘comforting,’ and varied product uses were associated with a mean liking increase. A key finding was that consumers viewed PBMs as distinct products with unique sensory attributes that conveyed specific emotions, perceptions, and uses, and achieved comparable liking to DM driven by the key sensory attributes. Moreover, continued consumption of dairy milk was due to a perceived ‘Need’ (p<0.0001).

Texture was identified as the most important attribute of PBM acceptance. Thus, in the fourth study, consumers (n=104) evaluated milks (n=5) through Temporal Dominance of Sensation (TDS), and the resulting texture perceptions were associated with particle size, viscosity, and tribological behavior by instrumental analysis. PBMs had a greater number of dominant sensory attributes, including thickness, smoothness, powdery, astringency, and creaminess, while DM only had smoothness and creaminess as TDS dominant perceptions. These sensory perceptions were correlated with the instrumental texture measures.

The novelty of this thesis was reflected in the development of fortified oat milk with improved sensory attributes and consumer liking, the consumer-based approach which provided relevant insights on consumer segments, perceptions, and consumption motivations, and in addressing the gap of limited use of dynamic methodologies and their integration to instrumental texture properties. This thesis is significant to academia and food industry by identifying drivers of liking, consumer perceptions, and insights on the PBM and DM product landscape.