Off-flavor is the main problem for potato protein to be sold in significant amounts as food ingredients. There are off-flavors formed as a part of indigenous enzyme activity. Among enzyme induced changes, redox enzymes lipoxygenases (LOX)1 giving rise to the formation of volatile secondary lipid oxidation products, e.g. 2-pentyl-furan and hexanal2. LOX activity is well-known in plants. However, its influence on potato protein quality is limited. Screening of LOX activity in five different potatos will be the first part of the project. A following lipidomics studies can be conducted using either LC-MS or GC-MS. To understand where in the production line the off-flavor is generated, the volatile secondary oxidation products can be quantified using solid phase micro extraction head space (SPME-HS) coupled to GC-MS.
Depending on the length of the study and the student, this study can be support by free radical analysis using electron spin resonance (ESR) using spin trapping and quantification of lipid hydroperoxides.
References:
1 Royo J, Vancanneyt G, Pérez AG, Sanz C, Störmanni K, Rosahli S, Sánchez-Serrano,JJ (1996). Characterization of Three Potato Lipoxygenases with Distinct Enzymatic Activities and Different Organ-specific and Wound-regulated Expression Patterns. The J Biol. Chem., 271: 21012–21019
2 Grebenteuch S, Kroh LW, Drusch S, Rohn S. Formation of Secondary and Tertiary Volatile Compounds Resulting from the Lipid Oxidation of Rapeseed Oil. Foods. 2021 Oct 12;10(10):2417. doi: 10.3390/foods10102417. PMID: 34681465; PMCID: PMC8535505.
The project is aligned to UN's SGD:
