You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Prooxidative and antioxidative properties of β-carotene in chlorophyll and riboflavin photosensitized oil-in-water emulsions. Effects of β-carotene on the oxidative stability of chlorophyll or riboflavin photosensitized oil-in-water (O/W) emulsions were determined by analysing the depleted headspace oxygen content, lipid hydroperoxides, fluorescence intensity, and headspace volatiles. As the concentration of β-carotene increased from 0 to 10, 100, and 1000μM, the oxidative stability of samples containing chlorophylls decreased in a concentration-dependent manner under light, indicating that β-carotene acted as a prooxidant. However, in riboflavin photosensitized O/W emulsions, 100 and 1000μM β-carotene inhibited lipid oxidation. Although β-carotene protected both photosensitisers in O/W emulsions, β-carotene displayed antioxidative or prooxidative properties, which depended on the polarity of the photosensitisers. The development of t-2-heptenal and 1-octen-3-ol increased greatly in chlorophyll sensitised O/W emulsions with an increase in β-carotene concentration, implying that more singlet oxygen oxidation occurred due to the higher levels of remaining chlorophylls. However, the content of t-2-heptenal and 1-octen-3-ol in the riboflavin sensitised O/W emulsions was not significantly correlated with the β-carotene concentration, which indicates that β-carotene in the lipid particles effectively quenched singlet oxygen.
{"Chemical": ["chlorophylls", "1-octen-3-ol", "hydroperoxides", "t-2-heptenal", "\u03b2-carotene", "oxygen", "chlorophyll", "riboflavin"]}