Effect of cyclodextrins on the flavour of goat milk and its yoghurt

The results in this thesis are confidential as described on page (iii). The thesis must not be given to anyone who is not directly involved in its examination. CONFIDENTIAL ii Acknowledgements First of all, I pay my sincere thanks to my supervisor, Associate Professor Owen Young, for his valuable supervision. A key factor behind this research was his encouraging, appreciative and tolerant attitude. I would also like to thank Thought Group Limited and Technology New Zealand for funding this research, under Enterprises Scholarship scheme. Also, I am thankful to Clyde Langford and Adam Hampson, who supplied free goat milk for this research. I would like to thank AUT laboratory technicians for their time and support. I am thankful to Applied Science and Engineering staff and students for being panellists on the sensory experiments held frequently during this study. I pay my sincere gratitude to my brother, Darshan Agarwal, for encouraging me to become qualified in food sciences. I appreciate the support and patience I got from my husband Sukhdarshan Gupta, and my son Vikram during my study. The contents of this thesis are confidential because of a commercial agreement with Thought Group Limited Auckland, and Technology New Zealand, parties that helped fund this work. The results have significant commercial value. However, it was agreed that confidentiality would lapse two years from submission of this thesis, after which time the author would be free to publish the results. Abstract Background and aim: A previous study showed that addition of β-cyclodextrin to goat milk made a difference to its flavour, but in an undescribed way. Cyclodextrins (CDs, comprising α-β-and γ-CD) may be able to bind the free branched chain fatty acids in goat milk responsible for the largely undesirable 'goaty' flavour. The primary aim was to test the effect of CDs on this flavour in goat milk and its products with a view to marketing goat milk products with reduced flavour intensity. A secondary aim was to test the effect of β-CD on skatole flavour, a characteristic flavour of milk from pasture-fed ruminants. Study design and methods: The present study evaluates addition of mainly β-CD to goat milk, cow milk and their products to reduce undesirable flavours. The methods applied were mainly ranking and hedonic assessment in sensory experiments. The tests done were with CDs added to buffers and milks, some of which were flavour-enhanced with 4-methyloctanoic acid as a representative goaty …