Characterisation of battered and breaded coatings for food systems

Voong, Amy Kha Yiu (2021). Characterisation of battered and breaded coatings for food systems. University of Birmingham. Eng.D.

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Abstract

Texture perception is due to a foods structural and mechanical properties detected through our senses. The texture of deep-fried battered and breaded coatings are recognised for their crisp outer crust contrasting a tender core. Crispness is a textural parameter used to assess the quality and freshness of deep-fried goods, it is therefore a fundamental attribute. The ultimate goal of this research is to understand the main drivers of crispness, thereby allowing an understanding of how crispness can be controlled from a formulation perspective. The ability to manipulate crispness is advantageous for developing a product to suit a desired specification or market niche.

The focus of this thesis is firstly directed towards gaining an understanding of the microstructure of deep-fried battered and breaded coatings. By characterising the microstructure of the entire coating, it was then possible to study the physical and mechanical properties and relate this to textural properties. The layers of a standard deep-fried coating consisted of predust flour, liquid batter layer followed by panko breadcrumbs. The breadcrumb layer is the first point of contact when biting and assessing texture, this initiated an incentive to investigate the effect of breadcrumb size on the physical and mechanical properties of the coating layer. Eight breadcrumb fractions were investigated for their effect on mechanical and physical properties of the deep-fried coating.

Instrumental characterisation was carried out using X-ray MicroCT, texture analysis, acoustics, confocal microscopy, Cryo-SEM, moisture and oil quantification. This concept was further explored by carrying out sensory studies. This consisted of using a trained sensory panel to develop a tailored lexicon for descriptive profiling. Results showed a significant difference in physical and mechanical properties as well as sensory attributes when breadcrumb size varied. These structural parameters were correlated with sensory parameters to develop a predictive statistical model for crispness. By using both instrumental and sensory characterisation methods, this provided a full representation of the contributors to crispness.

In the final chapter, consumer studies were carried out to understand consumer acceptance and preference. Cluster analysis confirmed that deep-fried battered and breaded coatings were grouping into three clusters (coarse, medium, fine). These clusters were based on dissimilarities instrumentally and sensorially. These three clusters of batter and breadcrumb coatings were carried forward for liking and acceptance testing. Consumers assessed these three samples on four hedonic and nine sensory attributes (9-point scale and JAR-scale). Penalty analysis confirmed significant mean drops within all three samples, highlighting which attributes can be focused on to improve overall hedonic score. Further cluster analysis confirmed consumers grouping into three clusters, each with a higher liking score for either coarse, medium or fine. Although crispness is a known important attribute for deep-fried coatings, results showed that when crispness is scored too high, overall liking score decreases. The results also highlight the microstructural differences in coatings that exceed the crispness limit. These microstructural properties explain why quality may be perceived as lower. It is also a combination of texture, flavour and appearance related attribute that significantly reduce overall liking score.

Type of Work:

Thesis (Doctorates > Eng.D.)

Award Type:

Doctorates > Eng.D.

Supervisor(s):