On food and cooking the science and lore of the kitchen ( PDFDrive ) 721

sweet oranges by a mixture of lycopene and beta-carotene and by cryptoxanthin The purple-red of blood oranges comes from anthocyanins Citrus anatomy The protective outer rind includes aromatic oil glands embedded in a bitter white pith, the albedo Each segment, or carpel, of a citrus fruit consists of many delicate juice sacs contained within a strong membrane The taste of citrus fruits is created by a handful of substances, including citric acid (so named because it is typical of the family), sugars, and certain bitter phenolic compounds, which are usually concentrated in the albedo and peel Citrus fruits are surprisingly rich in the savory amino acid glutamate, sometimes rivaling the tomato (oranges reach 70 milligrams per 100 grams, grapefruits 250) They contain little starch and therefore don’t sweeten much after picking Usually the blossom end of the fruit contains both more acid and more sugars, and so has a more intense taste than the stem end Neighboring segments can also vary significantly in taste Citrus aroma is produced both by the oil glands in the skin and oil droplets in the juice vesicles — and these two sources are usually quite distinct Generally the vesicle oils contain more fruity esters, and peel oil more green aldehydes and citrusy/spicy terpenes (p 274) A few aroma compounds are shared by most citrus fruit, including generically citrusy limonene and small amounts of eggy hydrogen sulfide In freshly made juice, the sac oil droplets gradually aggregate with the pulpy materials, and this aggregation reduces the aroma available to the taster, especially if some of the pulp is strained off  ...rivaling the tomato (oranges reach 70 milligrams per 100 grams, grapefruits 250) They contain little starch and therefore don’t sweeten much after picking Usually the blossom end of the fruit contains both more... glands in the skin and oil droplets in the juice vesicles — and these two sources are usually quite distinct Generally the vesicle oils contain more fruity esters, and peel oil more green aldehydes and citrusy/spicy terpenes (p... most citrus fruit, including generically citrusy limonene and small amounts of eggy hydrogen sulfide In freshly made juice, the sac oil droplets gradually aggregate with the pulpy materials, and this aggregation reduces the aroma available to the taster, especially if