FATTY ACID AND GLYCEROLIPID CHANGES DURING TUNISIAN MYRTLE (MYRTUS COMMUNIS VAR. ITALICA) FRUIT RIPENING

The neutral and polar glycerolipids as well as their fatty acid distribution in Myrtus communis var. italica fruit during its maturation were investigated. The increase of fruit weight (from 2.54 to 8.79%) during the ripening process was correlated positively with that of moisture (from 28.01 to 72.02%) and total lipid (TL; from 0.79 to 2.90%) contents. Myrtle fruit ripening was characterized by an increase in the neutral glycerolipid (NL) proportions (from 39.67 to 92.42% of TL) mainly represented by triacylglycerol (TAG) and a decrease of the levels of phospholipids (PL; from 41.09 to 4.32% of TL) and glycolipids (GL; from 19.23 to 3.25% of TL). Total fatty acids (TFA) of the fruit TLs were rich in linoleic (12.21-71.34% of TFA), palmitic (13.58-37.03% of TFA), oleic (6.49-21.89% of TFA) and alpha-linolenic (3.25-17.98% of TFA) acids. The fatty acid composition of TL was similar to that of different NL classes with the increase of polyunsaturated fatty acid (PUFA) proportions (from 16.57 to 74.58% of TFA) despite of saturated fatty acid (SFA; from 55.91 to 18.38% of TFA) and monounsaturated fatty acid (MUFA; from 27.39 to 7.02% of TFA) ones during the fruit ripening. However, the influence of fruit maturation on the PUFA proportions in different PL and GL fractions were obvious in contrast to those of in NL. PRACTICAL APPLICATIONS From a fundamental point of view, the survey of the evolution of the main fatty acids in neutral and polar glycerolipids could provide information about the glycerolipid variation during the myrtle fruit maturation. The survey of fatty acid distribution in the studied glycerolipids is of great interest since it could reveal information about the main glycerolipid classes containing the optimal fatty acid proportions which can be gave an idea about the nutritious value of the myrtle fruit. This latter was a good source of polyunsaturated fatty acid and triacylglycerol for the human diet and it could be used by the cosmetic and food industries.