mgr inż. Małgorzata Rak

ORCID: 0009-0005-0701-7352

The topic of my dissertation is: „Anthocyanin/anthocyanidin oxidation products as markers of food oxidation and oxidation in selected biological systems”

Description of the research topic:

During the storage or technological processing of food products, various chemical changes occur, one of the key ones being oxidation. This phenomenon significantly reduces food quality, contributing to the degradation of proteins and fats, especially under the influence of factors such as oxygen, light, and high temperature. These processes result in adverse organoleptic changes (loss of color, taste, change in consistency) and a decrease in nutritional value. In addition, oxidation can produce toxic compounds (e.g., peroxides) that pose a threat to human health. For these reasons, it is necessary to prevent oxidation processes and control their course.

Anthocyanins and their aglycones – anthocyanidins – are natural plant pigments belonging to flavonoids commonly found in fruits, vegetables, and flowers with intense red, purple, and blue colors. Their best sources are berries, i.e., blueberries, blackcurrants, black raspberries, black carrots, and red cabbage. Due to their coloring properties, anthocyanins and anthocyanidins are used in the food industry as natural dyes marked with the symbol E163. They have strong antioxidant properties, and their ability to neutralize free radicals and reactive oxygen species makes them important bioactive compounds that protect cells from oxidative stress and are potential preventive factors in the development of many diseases, such as cancer and neurodegenerative diseases. However, as a result of external factors (temperature, pH, light, presence of metals), they can undergo degradation, leading to the formation of oxidation products such as chalcones, phenolic acids, and aldehydes. Anthocyanins and anthocyanidins exhibit both light-absorbing and fluorescent properties. Their ability to absorb and emit light depends on their chemical structure, the pH of the environment, and the presence of other compounds. Studies show that as a result of oxidation, anthocyanins and anthocyanidins form new compounds that exhibit more intense fluorescence than their precursors; moreover, the intensity of fluorescence is related to the concentration of the oxidizing agent. Due to the formation of characteristic fluorescence signals, it can be assumed that anthocyanin/anthocyanidin oxidation products can be used as markers of oxidative processes in food and as fluorescence probes in biomedical research. Despite the growing number of studies on the properties and stability of anthocyanins/anthocyanidins, there is still a clear research gap in terms of their full identification, biological activity, and validation as practical markers of quality and oxidative status.

The aim of the research will be to identify and characterize the main products of anthocyanin/anthocyanidin oxidation anthocyanidins responsible for generating “new fluorescence” and to determine whether changes in light absorption spectra, and in particular the “new fluorescence” characteristic of the oxidation product of these pigments, correlate with food quality and the intensity of oxidation processes in selected biological systems.

The expected results of research into anthocyanin/anthocyanidin modification in two different contexts – food and biological systems – represent an innovative approach that could make a significant contribution to the development of new methods for monitoring food quality and could be a valuable tool in biological research on many diseases and pathological conditions, such as oxidative stress, which plays an important role in neurodegenerative diseases and cancer. Their potential use as markers of food oxidation and oxidation in biological systems is promising, as it may lead to the development of new, more effective methods for controlling food degradation processes and a better understanding of the mechanisms of oxidation in cells.

Publication:

1. Rak M., Mendys D., Płatek A, Sitarz O., Stefaniuk I., Bartosz G., Sadowska-Bartosz I. 2025. Generation of Hydrogen Peroxide in Beer and Selected Strong Alcoholic Beverages. Processes, 13(1), 227. DOI: 10.3390/pr13010277
2. Rak M., Bartosz G., Sadowska-Bartosz I. 2025. A New Fluorescence Band of Anthocyanins as a Simple Oxidation Biomarker of Food Products. Molecules, 30(12), 2510. DOI: 10.3390/molecules30122510
3. Rak M. Analysis of microbiological composition of deep-frozen meet of selected game animals stored in the refrigeration. Annales Universitatis Paedagogicae Cracoviensis Studia Naturae, 10(1). DOI: 10.24917/25438832.10.x
4. Rak M., Bartosz G., Sadowska-Bartosz I. 2025. Effect of Fermentation With and Without the Addition of Carrots on the Total Antioxidant Capacity of White and Red Cabbage. Processes, 13(9), 2928. DOI: 10.3390/pr13092928