Growth and compositional changes during development and ripening of early summer 'Lonet-Mesaed' date palm fruits

'Lonet-Mesaed' is one of early season date palm cultivars consumed at both the Bisir and the Rutab stages as a result of low soluble tannins level. Growth and compositional changes during development and ripening of 'Lonet-Mesaed' date palm fruit were studied in two successive seasons. The results showed that fruit and flesh weight, diameter and length gradually increased during development until week 14 from pollination (maturity or Bisir stage) but slightly decreased thereafter during ripening at week 16 from pollination (ripening or Rutab stage). The changes in these parameters showed a clear sigmoidal pattern for fruit growth. Seed weight rapidly increased especially from week 6 to 10 (cell elongation or Kimri stage), slightly increased from week 10 to 12 and then decreased at week 16 from pollination. Flesh/seed ratio was sharply decreased from week 6 to 10 from pollination but then gradually increased until ripening. TSS and flesh dry weight percentage slightly increased from week 6 to 10 from pollination and then rapidly increased during maturation and ripening. Acidity percentage sharply decreased from week 6 to 8, remained relatively constant until week 12 from pollination and then slightly increased during maturation and ripening. The concentration of vitamin C increased from week 6 to 8 from pollination but sharply decreased thereafter during maturation and ripening. On a fruit basis, the amount of vitamin C (mg/fruit) increased from week 6 to 8 and decreased at week 10 from pollination with slight changes during maturation and ripening. Total phenol concentration gradually increased during development, slightly decreased during maturation and then sharply decreased during ripening. As amount per fruit total phenols followed a similar pattern as for the concentration. The concentration of soluble tannins increased from week 6 to 8, decreased with fluctuation from week 8 to 14 and then sharply decreased during ripening. However, as amount per fruit, the soluble tannin content gradually increased during development, slightly decreased during maturity and then sharply decreased during ripening. On a dry weight basis, the concentration of all nutrient elements (nitrogen, potassium, phosphorus, magnesium, calcium, sodium, zinc, iron, copper and manganese) gradually decreased during development and more progressively during ripening.