The effect of UV light and spray drying on glucosamine non-enzymatic browning

  • Author / Creator
    Zou, Fuyao
  • Non-enzymatic browning reactions, including Maillard and caramelization, are important and complex reactions occurring during food processing and storage. Many factors can affect non- enzymatic browning reactions, which include the concentration of reactants, initial pH, temperature, heating time, water activity, etc.
    Glucosamine (GlcN) is an amino monosaccharide that contains both an amino group and a carbonyl group. It is capable of undergoing non-enzymatic browning at lower temperatures, generating a plethora of desirable compounds, including α-dicarbonyl compounds (α–DCs), fructosazine (FR) and deoxyfructosazine (DOFR), melanoidins, etc. Among the major α-DCs, 3- deoxyglucosone (3-DG), glucosone (G), methylglyoxal (MGO), glyoxal (GO) and diacetyl (DA) can be generated from GlcN at as low as 25 °C, while increasing the reaction temperature to 37 or 50 °C can speed up this degradation process. MGO, GO, DA, and 3-DG have been reported to have antibacterial activities. Apart from α-DCs, FR and DOFR are the self-condensation products of GlcN. The latter have been reported to have anti-inflammatory properties and are applied in therapeutic uses. At the same time, non-enzymatic browning reactions can generate potential toxic compounds, including 4-methylimidazole (4-MEI), 2-acetyl-4-tetrahydroxybutylimidazole (THI), and 5-hydroxymethylfurfural (5-HMF).
    The first study aimed to examine the non-enzymatic browning of GlcN under UV-C radiation at 25 °C, referred as “cold caramelization”. Several UV-C exposure times were studied, including 0, 20, 60, 120 min at two GlcN concentrations of 15% and 30%. The physico-chemical properties, quantitation of α-DCs and polyhydroxylalkyl pyrazines (FR and DOFR), alkylimidazoles and 5-hydroxymethylfurfural were determined in all resulting GlcN caramels. The results revealed the possibility of generating GlcN caramel containing desirable compounds by
    applying UV-C. Specifically, longer UV-C exposure time produced caramel with higher content of G and 3-DG, as well as the GlcN self-condensation products, FR and DOFR. The amount of glucosone was significantly higher compared to GlcN caramels produced under heat treatment. Additionally, none of the neo-formed contaminants were detected during the process. Thus, UV- C treatment may be a newly advantageous method for producing GlcN caramel.
    The second study focused on the effect of spray-drying on the non-enzymatic browning of GlcN incubated at 50 °C and 90 °C for 12 h. The resulting spray-dried GlcN caramel powders were analyzed along with the non-spray-dried GlcN caramel solutions to compare their physico- chemical properties and concentrations of polyhydroxylalkyl pyrazines, alkylimidazoles, and heterocyclic compounds. Spray-dried GlcN caramels were found to have lower concentrations of both non-volatile FR and DOFR, as well as THI and 5-HMF.
    In summary, this thesis examined the non-enzymatic browning of GlcN under the application of UV-light and spray-drying, which revealed the possibilities of creating desirable caramels containing bioactive compounds. The resulted caramels can be potentially applied in different food applications.

  • Subjects / Keywords
  • Graduation date
    Spring 2022
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.