Bitterness and flavanone composition of ‘Redson’ fruit: A new red-fleshed pomelo × grapefruit hybrid

‘Einat’ (‘Redson™’) is a new triploid, red-fleshed pomelo × grapefruit hybrid. We examined the quality, flavor, bitterness and flavanone composition of ‘Redson’ fruit, as compared to 'Oroblanco', another pomelo x grapefruit hybrid, 'Star Ruby' grapefruit, 'Goliath' pomelo and 'Newhall' navel orange. ‘Redson’ fruit are seedless with a yellow peel and red flesh and have unique quality characteristics. Descriptive sensory tests revealed that ‘Redson’ fruit are bitterer than other citrus fruit, but earned a high consumer acceptance score and ranked first for preference among all bitter citrus fruits, including pomelo, grapefruit and their hybrids. ‘Redson’ fruit contained the highest amount of the bitter flavanone naringin, but had low levels of other bitter flavanones (neohesperidin and poncirin) and non-bitter flavanones (hesperidin and narirutin). Furthermore, we detected a high correlation (R² = 0.957) between naringin levels and the sensation of bitterness among citrus fruit, featuring the importance of naringin in determining citrus bitterness.