PhD Thesis abstract published online as a service to the JDR Community.
Understanding aroma and flavour formation in baked confectionery products, as influenced by sugar and fat
Emer Garvey
Ireland
Emer Garvey
Ireland
Abstract
This thesis directly addresses consumer demands for more ‘clean-label’ sustainable and natural ingredients. Baked confectionery products are a prime matrix to explore alternative sucrose replacers due to the critical functionality of sucrose and fat to the desirable structure and organoleptic properties. The primary objective of this research was to elucidate the influence of sugar and butter on sensory perception, focussing on changes in volatile profile.
To identify important volatile compounds, Chapter 2 outlines the development and optimisation of a headspace solid-phase microextraction gas-chromatography mass-spectrometry (HS-SPME-GC-MS) method for the extraction of volatile compounds from a baked confectionery matrix. Extraction parameters; fibre type, incubation time, extraction time and extraction temperature were chosen for optimisation. The optimum, validated HS-SPME-GC-MS method consisted of a 50/35um DVB/CAR/PMDS fibre with a 5 min incubation time, 60 min extraction time at 60°C. This method was then applied throughout all subsequent volatile analysis. Chapter 3 explored the influence of clean-label sucrose replacers on the sensory quality and volatile aroma profile of sponge cakes. Gas-chromatography-olfactory (GC-O) was applied to evaluate the impact of sucrose replacers on aroma perception, whilst, consumer evaluation and ranking descriptive analysis (RDA) were employed to understand changes in sensory attributes. To further appreciate the contribution of sucrose to aroma formation, the influence of sucrose particle size manipulation, and sucrose source (beet or cane sugar) was explored in sponge cakes (Chapter 4). Salted butter flavour, and the ability of its sensory properties to translate into shortbread biscuit, was explored (Chapter 5 and Chapter 6). An initial study (Chapter 5) looked to understand if the production of butter, from a pasture and non-pasture bovine diets, had different sensory characteristics, and if sensory perception differed in a cross-cultural context. Consumer studies were conducted in Ireland, Germany and the USA, whereas, RDA was conducted in Ireland and Germany, and descriptive analysis (DA) in the USA. The last experimental chapter (Chapter 6) utilised the butter produced for the same bovine diets and incorporated it into shortbread biscuits. Consumer liking tests were conducted, with temporal assessment, using temporal-check-all-that-applies (T-CATA) employed to further understand the melting behaviour of the butter biscuit during consumption.
Key findings of this research demonstrate the composition of sucrose replacers, particularly when containing reducing sugars, can accelerate Maillard (MR) and Caramelisation (CR) reactions, and hence influence the sensory perception. ‘Spicy/bready’ furfural contributed most to the overall aroma of all samples, with factor dilution values differing the most for ‘fatty cake crust’ heptanal and ‘potato damp’ methional, between the control (100% sugar), and the 30% w/w reduced sugar with apple pomace powder and oligofructose, respectively. Sucrose source did not demonstrate a significant (P < 0.05) effect on the volatile profile in sponge cakes; however, small sugar crystals have the ability to positively influence MR and CR compounds. No significant difference (P < 0.05) was identified in the overall liking, among USA, German and Irish consumers, of the experimental butters-although cross-cultural preferences were evident. Sensory attribute differences based on cow diet were likely influenced by familiarity. The colour of shortbread biscuits formulated with pasture was perceived favourable by consumers due to the more golden colour, as a result of higher β-carotene content in the biscuit. The temporal profile of the butter biscuits can be profiled, with stages of oral processing; orthonasel, in-mouth and aftertaste, differentiating mainly due to the difference in fatty acid profile. This PhD thesis has highlighted the unique approach and significant potential of combining multiple sensory techniques, volatile profiling and olfactometry to best elucidate the impact of formulation changes in baked confectionary products on sensory perception to improve our overall understanding of flavour development in these products.
This thesis directly addresses consumer demands for more ‘clean-label’ sustainable and natural ingredients. Baked confectionery products are a prime matrix to explore alternative sucrose replacers due to the critical functionality of sucrose and fat to the desirable structure and organoleptic properties. The primary objective of this research was to elucidate the influence of sugar and butter on sensory perception, focussing on changes in volatile profile.
To identify important volatile compounds, Chapter 2 outlines the development and optimisation of a headspace solid-phase microextraction gas-chromatography mass-spectrometry (HS-SPME-GC-MS) method for the extraction of volatile compounds from a baked confectionery matrix. Extraction parameters; fibre type, incubation time, extraction time and extraction temperature were chosen for optimisation. The optimum, validated HS-SPME-GC-MS method consisted of a 50/35um DVB/CAR/PMDS fibre with a 5 min incubation time, 60 min extraction time at 60°C. This method was then applied throughout all subsequent volatile analysis. Chapter 3 explored the influence of clean-label sucrose replacers on the sensory quality and volatile aroma profile of sponge cakes. Gas-chromatography-olfactory (GC-O) was applied to evaluate the impact of sucrose replacers on aroma perception, whilst, consumer evaluation and ranking descriptive analysis (RDA) were employed to understand changes in sensory attributes. To further appreciate the contribution of sucrose to aroma formation, the influence of sucrose particle size manipulation, and sucrose source (beet or cane sugar) was explored in sponge cakes (Chapter 4). Salted butter flavour, and the ability of its sensory properties to translate into shortbread biscuit, was explored (Chapter 5 and Chapter 6). An initial study (Chapter 5) looked to understand if the production of butter, from a pasture and non-pasture bovine diets, had different sensory characteristics, and if sensory perception differed in a cross-cultural context. Consumer studies were conducted in Ireland, Germany and the USA, whereas, RDA was conducted in Ireland and Germany, and descriptive analysis (DA) in the USA. The last experimental chapter (Chapter 6) utilised the butter produced for the same bovine diets and incorporated it into shortbread biscuits. Consumer liking tests were conducted, with temporal assessment, using temporal-check-all-that-applies (T-CATA) employed to further understand the melting behaviour of the butter biscuit during consumption.
Key findings of this research demonstrate the composition of sucrose replacers, particularly when containing reducing sugars, can accelerate Maillard (MR) and Caramelisation (CR) reactions, and hence influence the sensory perception. ‘Spicy/bready’ furfural contributed most to the overall aroma of all samples, with factor dilution values differing the most for ‘fatty cake crust’ heptanal and ‘potato damp’ methional, between the control (100% sugar), and the 30% w/w reduced sugar with apple pomace powder and oligofructose, respectively. Sucrose source did not demonstrate a significant (P < 0.05) effect on the volatile profile in sponge cakes; however, small sugar crystals have the ability to positively influence MR and CR compounds. No significant difference (P < 0.05) was identified in the overall liking, among USA, German and Irish consumers, of the experimental butters-although cross-cultural preferences were evident. Sensory attribute differences based on cow diet were likely influenced by familiarity. The colour of shortbread biscuits formulated with pasture was perceived favourable by consumers due to the more golden colour, as a result of higher β-carotene content in the biscuit. The temporal profile of the butter biscuits can be profiled, with stages of oral processing; orthonasel, in-mouth and aftertaste, differentiating mainly due to the difference in fatty acid profile. This PhD thesis has highlighted the unique approach and significant potential of combining multiple sensory techniques, volatile profiling and olfactometry to best elucidate the impact of formulation changes in baked confectionary products on sensory perception to improve our overall understanding of flavour development in these products.
Affiliation and Awarding Institution: University College Cork, Ireland
Corresponding E-mail address: 117221652@umail.ucc.ie
Availability of full Thesis: please contact author
Corresponding E-mail address: 117221652@umail.ucc.ie
Availability of full Thesis: please contact author
Abstract published 15 January 2021. Thesis to be defended, February 2021
