Physico-chemical chlorophyll-a species in aqueous alcohol solutions determine the rate of its discoloration under UV light
| Autor: | Midori Yasuda, Keisuke Oda, Masaaki Tabata, Toshihisa Ueda |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Chlorophyll a
Chemical Phenomena Ultraviolet Rays Alcohol macromolecular substances 01 natural sciences Analytical Chemistry chemistry.chemical_compound 0404 agricultural biotechnology polycyclic compounds Particle Size J-aggregate Ethanol Aqueous solution Chlorophyll A Methanol 010401 analytical chemistry food and beverages 04 agricultural and veterinary sciences General Medicine 040401 food science 0104 chemical sciences Monomer chemistry Solvents Particle size Food Science Nuclear chemistry |
| Zdroj: | Food Chemistry. 277:463-470 |
| ISSN: | 0308-8146 |
| DOI: | 10.1016/j.foodchem.2018.11.005 |
| Popis: | Chlorophyll-a (Chl-a) discolors when it is exposed to light, and such discoloration decreases food quality. To elucidate the discoloration mechanism of Chl-a, we determined discoloration rate in different Chl-a chemical species and assessed the size of Chl-a aggregates in mixed aqueous solutions of methanol and ethanol. Chl-a existed as monomer, J-aggregate, and random aggregate in solutions with different alcohol concentrations. The predominant species depended on the alcohol concentration. Monomeric Chl-a and J-aggregates discolored quickly, whereas random aggregates discolored slowly. Particle sizes of J-aggregates were 319 and 2305 nm in diameter in aqueous solutions of methanol and ethanol, respectively. The sizes of random aggregates were 51 and 79 nm in 10% (v/v) aqueous solutions of methanol and ethanol, respectively. The size of Chl-a aggregates positively correlated with the rate of Chl-a discoloration under UV light. Based on the results obtained, we propose a mechanism of Chl-a discoloration. |
| Databáze: | OpenAIRE |
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