Biochemical characterization of the mesocarp in distinct apricot (P. armeniaca) genotypes

Apricot fruit handling and shipping is often impaired by soft flesh texture. Within the apricot germplasm very diverse genotypes differing in mesocarp texture are found. The present study was undertaken to gain greater understanding of the biochemical and physical properties of these fruits. Fruits from fourteen apricot cultivars differing in flesh texture were tested at three different ripening stages (green, breaker and full ripe) for firmness and skin background colour and analyzed for soluble and insoluble pectins, total and pectin-bound calcium. Flesh firmness measurement by penetrometer was found unreliable for assessing flesh texture and compactness. The calcium increased in flesh throughout ripening, suggesting that uptake is active until the final stage of fruit development. Variability in flesh total calcium could not be associated per se to firmness or texture, although it could be very high in very firm cultivars. The allocation of calcium to pectins did not depend on flesh firmness or texture. Variability in pectins (particularly the water insoluble fractions) could possibly explain the high differences found in sensory evaluation of flesh texture in some very firm and compact apricots.