Study On The Rule Of Oil Accumulation And The Activities Of Related Synthetic Enzymes In Olive Pulps Of Introduced Cultivars

This article was conducted on five kinds of olive varieties from foreign countries, they were Frantoio, Arbequina, Coratina, Koroneiki and Picual. After choosing these olive trees as experimental materials which were growing in Xichang and taking Ezhi from domestic as control check(CK), the study analyzed oil accumulation and changes in lipid synthetic activities during fruit-filling stage. The results were as follows.1Changes of oil accumulation in pulps of different olive varieties1.1Changes of crude fat (CF)The changes of the CF content in pulps mostly went up during the growth of fruit and began decreasing in the mature period. The maximum CF content of olives in decreasing order were Arbequina, Frantoio, Coratina, CK, Koroneiki and Picual. And in the mature period, the average CF content of olives in decreasing order were Koroneiki, Arbequina, Frantoio, CK, Coratina and Picual.1.2Changes of free fatty acids (FFA)During the growth period of fruit, the amount of FFA in pulps of all olive varieties, which were used for producing TG, showed downward trends. The minimum FFA values of olives in increasing order were Coratina, Picual, CK, Arbequina, Koroneiki and Frantoio. And in the mature period. And in the mature period, the average FFA values of olives in increasing order were Picual, Coratina, Arbequina, CK, Koroneiki and Frantoio.1.3Changes of unsaturated fat acids(UFA)During the growth of fruit, the amount of UFA in pulps of most olive varieties mainly showed a slight decrease and rose until the peak values, then dropped slightly again. The maximum UFA content of olives in decreasing order were Picual, Koroneiki, CK, Arbequina, Coratina and Frantoio. And in the mature period, the average UFA content of olives in decreasing order were Koroneiki, Picual, Arbequina, CK, Frantoio and Coratina.1.4Changes of amounts in fatty acid compositionThe Fatty Acids(FA) in olive pulps were mainly composed of oleic acid(OA), linoleic acid(LA), palmitic acid(PA), α-linolenic acid(ALA), stearic acid(SA) and palmitoleic acid(POA). And OA accounted for the highest percentage of the FA. Changes of FA composition in pulps of every variety was obvious during fruit-filling stage and they turned out upward trends in the stage of prometaphase, then changed as wave-like curves, up or down.2Changes of lipid synthesize enzymes activities in pulps of different olive varieties2.1Changes of ACCase activities in pulps of different olive varietiesThe changes of ACCase activities of every variety showed single-peak curves. The ACCase activities of all the introduced varieties performed significant or very significant difference for much of the fruit-filled stage, compared with CK. It illustrated that the changes of ACCase activities of all the varieties were different.2.2Changes of PPase activities in pulps in different olive varietiesThe changes of PPase activities of every variety showed single-peak curves. The PPase activities of Arbequina, Coratina, Koroneiki and Picual performed significant or very significant difference for much of the fruit-filled stage. It illustrated that the changes of PPase activities of separate varieties were different.3Correlation analysis3.1Correlation analysis between ACCase activities and CF contentThe changes of ACCase activities of each olive variety looked like the same as CF content except the ACCase activities achieved the maximum earlier and decreased much more. The changes of ACCase activities were positively correlated with CF content. And the changes of Arbequina, Picual and CK showed significant positive correlation. It illustrated that ACCase, as the regulating enzyme involved in the first step of the synthesis of fat, its activities regulated the changes of CF content.3.2Correlation analysis between PPase activities and CF contentThe changes of PPase activities of every olive variety looked like the same as CF content except the PPase activities achieved the maximum earlier. The changes of PPase activities were positively correlated with CF content. And the correlation coefficient of Picual was significant difference. It illustrated that PPase activities had an important effect on the accumulation of CF.4The conclusion4.1The optimal harvest timeTaking into account the FFA content and the unsaturated fatty acid content in the mature period(160to230days after flowering), the optimal harvest time of Frantoio, Arbequina, Coratina, Koroneiki, Picual and CK was the time of190days after flowering, which was10-20d later than the usual harvest dates.4.2Variety EvaluationArbequina, Koroneiki and Picual were superior to CK, which were the most adapted and suitable varieties for promotion in the region. On the other hand, Frantoio and Coratina showed no better than CK, and needed to go on observing in trial.