Metabolic Profiling and Fingerprinting for the Detection and Discrimination of Mechanical Damage in Mushrooms (Agaricus bisporus) during Storage

Aoife O'Gorman (Thesis), Dublin Institute of Technology

Document Type Theses, Ph.D

Successfully submitted for the award of Doctor of Philosophy (Ph.D.) to the Dublin Institute of Technology, October, 2010


Horticultural products such as mushrooms are exposed to external agents during their postharvest life, which are going to affect product quality. Loss of whiteness during storage is particularly important in the mushroom industry. Rough handling and distribution of crops, fruiting body senescence, bacterial and viral infection are among the causes of mushroom discolouration. The aim of this work was to study the use of metabolic fingerprinting and
metabolic profiling tools for the detection and discrimination of mechanical damage on mushrooms. This research involved:
1. Investigating whether the chemical changes induced by mechanical damage and ageing of mushrooms could be (a) detected in the mid-infrared absorption region using FTIR spectroscopy as a fingerprinting tool and (b) identified using chemometric data analysis.
2. Investigating metabolites in mushroom tissues using GC/MS as a metabolic
profiling technique. The method was used to profile mushroom samples to identify metabolic markers for damage and to gain understanding of the many metabolic processes that occur.
3. Studying low levels of damage in mushrooms using NMR spectroscopy as a
fingerprinting technique coupled with chemometrics to identify markers and
determine metabolite structure. The results from this study show the usefulness of FTIR spectroscopy coupled with chemometric data analysis for evaluating damage in mushrooms with specific wavenumbers identified. Metabolic profiling using GC/MS has led to a library of metabolites being built. Specific metabolites have been identified as markers for damage.