Study On Coloring Physiological And Biochemical Characteristics In Apricot Fruits

Apricot is a deciduous tree of Armennica, Prunoideae, Rosaceae. People enjoy apricotfruit very much as its unique flavor, gorgeous color and luster, and rich nutrition. Nevertheless,it appeared that coloration of apricot fruit was not stable in the production. It led to the declineof economic benefits. In order to provide theoretical guidance for the production of highquality apricot fruit, three apricot cultivars, i.e. Fengren, Yinxiangbai, Chuanzhihong, wereused to investigate the changes of fruit diameter, fresh weight, volume, color of peel and flesh,sugar and acid, pigment substance (anthocyanin, chlorophyll, carotenoid, flavonoid), totalphenolics concentration and PPO activity, and correlation among them. Moreover, sugar andacid and pigment substance concentration was studied when ripe in ten apricot cultivars. Theresults showed that:1. The fruit growth and development period of Fengren (kernel apricot cultivar) can bedivided approximately into the fast growth period, the slow growth period of fruit. Thevertical diameter, transverse diameter, lateral diameter, fresh weight and volumet dynamicsrhythm of Yinxiangbai and Chuanzhihong (flesh apricot cultivar) showed obvious "double S"growth curve.2. On the early stage of apricot fruit development, color of flesh and peel was green.During middle and later development, the fruit color change had obvious difference amongvarieties. Both flesh and peel color in Fengren were from green to orange-yellow. ForYinxiangbai, flesh color was from green to white, peel color to green-white, with red spot insunny side of peel. For Chuanzhihong, both flesh and peel color were from green toorange-yellow, with3/4purplish red in peel.3. During apricot fruit development, in the flesh, the content of soluble total sugar andnon-reducing sugar increased all the times. The content of titratable acid increased slowly atfirst and then decreasd sharply. For Fengren, reducing sugar was the main component of totalsugar. For Yingxiangbai and Chuanzhihong, on the early stage, reducing sugar was the maincomponent of total sugar; but on the later stage, non-reducing sugar became the maincomponent.4. During apricot fruit development, in the peel, the content of chlorophyll decreased all the times. The content of carotenoid decreased at first and then increased, and then decreased.The content of flavonoid decreased at first and then increased, and then decreased. Theanthocyanin pigments were not detected in the peel of Fengren during the entire development.With the maturation of the fruit, the anthocyanin content in the peel of Yinxiangbai andChuanzhihong increased gradually. Significant (P＜0.05) or significant (P＜0.01) negativecorrelation between anthocyanin and chlorophyll, and significant (P＜0.01) positive correlationbetween anthocyanin in the peel and soluble total sugar and non-reducing sugar in the fleshwere observed.5. During apricot fruit development, in the peel, for Fengren, the content of totalphenolics kept a stable lower level before61days after full bloom, and then increased sharply.For Yinxiangbai and Chuanzhihong, the content of total phenolics decreased at first and thenincreased, and then decreased. Significant (P＜0.05) positive correlation between totalphenolics and PPO was observed in Yingxiangbai.6. Soluble total sugar was significant (P＜0.05) lower and titratable acid was significant(P＜0.05) higher in the kernel apricot cultivars than in the flesh apricot cultivars; the reducingsugar was no significant differences between them. Anthocyanin was only located in the peelof red apricot varieties. As a general rule, contents of pigments in both flesh and peel ofapricot cultivars were significant (P＜0.05) higher than that of flesh apricot cultivars; the peeltissues contained significant (P＜0.05) higher amounts of pigments than the flesh tissues inthe same variety. Contents of soluble total sugar, titratable acid, and carotenoid weresignificantly (P＜0.05) different among three flesh color groups. The carotenoid content wascorrelated significantly (P＜0.05) with the flesh color (r=0.872). No significant correlationbetween the flesh color and chlorophyll, flavoniod, and sugar acid was observed. All showedthat the red appearance in the peel of apricot resulted in anthocyanin, while the color of fleshwas mainly determined by carotenoid.