Premium
Identification of Beta‐Carotene Degradation Compounds and Their Structural Elucidation by High‐Resolution Accurate Mass Spectrometry
Author(s) -
Xu Minren,
Chen Tom,
Butt Craig M.
Publication year - 2019
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/1750-3841.14909
Subject(s) - chemistry , mass spectrometry , dehydrogenation , double bond , chromatography , mass spectrum , stoichiometry , fragmentation (computing) , beta carotene , photochemistry , vitamin , organic chemistry , catalysis , operating system , biochemistry , computer science
Beta‐carotene (BC) degradation was studied by liquid chromatography coupled to a quadrupole time of flight mass spectrometer. Throughout/After 21 days of dark storage, 56 nonvolatile degradants were chromatographically separated from pure BC crystal and their molecular formulas were identified. Their structure information was gained by comparing the fragments to a different, but structure‐related compound. For example, a newly formed double bond position in dehydrogenated BC was determined by comparing the fragments between BC and dehydrogenated BC. One of their chemical structures was confirmed by comparing its precursor ion mass, retention time, isotopic ratio, and fragmentation to a pure trans ‐beta‐apo‐8′‐apocarotenal. BC cleavage was observed on double bonds as well as single bonds in BC conjugation chain. Practical Application As evidenced in this study, beta‐carotene (BC) degradation is a spontaneous process initiated when the compound is exposed to air. The stoichiometric ratio of BC to oxygen is 1:0.03 at the first oxidation, therefore, only 0.3 mg oxygen or 1.2 mL air will degrade 10 mg BC, an average daily recommended intake. Not like in enzymatic BC degradation, spontaneous BC oxidation did not produce provitamin A, either in retina C20H38O or retinol C20H40O forms. For BC application in vitamin A deficiency, spontaneous BC oxidation should be avoided.