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Type: Thesis
Title: Defining the impact of flavour interactions in protein based food matrices
Author: Sanderson, Jessica
Issue Date: 2016
School/Discipline: School of Agriculture, Food and Wine
Abstract: Flavour is widely accepted as a major determinant of consumer satisfaction, so factors that influence flavour quality are of great interest to both food scientists and the manufacturing industry globally. Volatile organic compounds (VOC) play an important role in characterising the unique flavour profile of foods. However non-volatile matrix solutes are capable of selectively binding these compounds and modifying their availability for perception during consumption. The impact of carbohydrates and lipids has been extensively studied which has led to a comprehensive understanding of the principles governing their interaction with flavour volatiles. Proteins, in comparison, remain poorly understood. This is due mainly to their structural diversity and resulting range of available binding mechanisms which can change in response to environmental conditions such as those encountered during food processing. Myofibrillar proteins are compositionally significant components of skeletal muscle tissue and play a critical role in defining the textural properties of processed meat products including burgers and sausages. To determine their influence on flavour, a series of model solutions were analysed and partition coefficients Kg-m calculated to enable changes in compound volatility to be measured. Eleven different flavour volatiles were evaluated, including a number of plant derived bioactive compounds not previously considered in binding studies. Partition coefficients were measured using static headspace-gas chromatography (SH-GC) methods partnered with indirect phase ratio variation (PRV) techniques. The retention effect of myofibrillar proteins was quantified by reporting the percentage change in Kg-m following the introduction of protein extract into the system. Myofibrillar proteins were obtained from a series of extractions of pork loin fillet with sodium phosphate buffer. The process yielded 58.6 mg/g of muscle which accounted for an approximate recovery rate of 60% of total available proteins. Subsequent instrumental analysis confirmed that at 35°C, a 2 mg/mL protein extract was capable of binding all volatile compounds, to various degrees, reducing their volatility, or headspace concentration, and therefore the availability of each compound for sensory perception. The greatest effect was recorded for isomers citral and neral, with 55.9% and 59.1% retention reported respectively, followed by ethyl hexanote which gave 36.7% retention. Thymol and carvacrol followed closely, with 28.6% and 33.7% retention respectively. Data collected throughout the study strongly indicates that myofibrillar proteins interact predominantly via weak reversible associations that are enhanced with increasing levels of flavour compound hydrophobicity. Both SH-GC and PRV are commonly utilised in flavour interaction investigations and are known to have areas of limitation that must be considered throughout application. During instrumental method development however, a significant obstacle was encountered which had not been documented previously. After considerable method development, it was concluded that mass spectrometer (MS) detectors are not suitable for use in PRV trials due to the repeated injection of headspace water vapour into the system. This damaged MS components and limited the ionisation of analytes required for their detection.
Advisor: Wilkinson, Kerry
Dissertation Note: Thesis (MPhil) -- University of Adelaide, School of Agriculture, Food & Wine, 2016
Keywords: Flavour interaction
Partition coefficient
Aroma retention
Volatile binding
Myofibrillar protein
Phase ratio variation (PRV)
Provenance: This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at:
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