| Olive{Olea europaea L.) is one of four major world woody oil plants and its oil has highly health-promoting value. The fine characteristic and biological activity of olive oil are mainly due to the presence of components, such as the optimal balance among monounsaturated, polyunsaturated and saturated fatty acids, as well as to minor components, such as polyphenols, phytosterols, chlorophyll and tocopherols. The olive cultivation in our country is in development period, and the impact of the maturity on olive fruit quality is rarely reported. In this paper, the phenotypic traits of olives (fruit longitudinal diameter, fruit transect diameter, single fruit weight, nuclear weight, fruit volume, etc.), and the contents of oil, total polyphenol, reducing sugar, protein and moisture in fresh fruits, as well as fatty acids composition and squalene in olive oil, and the phenolic composition of fresh fruits were measured during the six maturity stage. At the same time, the fruits quality of 10 olive varieties in six maturity were comprehensive evaluated by correlation analysis and principal component analysis in order to find the best maturity for olives and provide a theoretical basis for rational exploitation. The main results were as follows:1. The fruits phenotypic traits in 10 olive varieties with six maturity were determined and the results showed that the fruit size, single fruit weight, flesh-stone ratio increased with maturity increasing. And the maximum value appeared in the 4th,5th maturity, after which, it would decline slightly. The correlation analysis of each index showed that flesh-stone ratio, fruit volume and fruit diameter were significantly correlated with maturity, and fruit size, diameter were significantly correlated with varieties. The principal component analysis of fruit phenotypic traits showed that the 5th and 6th were best maturity in most varieties; compared scores of optimum maturity of each variety and the scores from high to low were as follows:Picual, Ezhi, White olives, Vuntai, Frantoio, Douguo, Kalinjot, Koroneiki, Pendollino, Coratina.2. The contents of oil, total polyphenols, reducing sugar, protein and moisture of fresh olives in 10 olive varieties with six maturity were measured. The result showed that the content of oil kept steady after initial increased; total polyphenols, reducing sugar and protein had slightly increased after initial declined; and the content of moisture had little change. The correlation analysis showed that the contents of oil, total polyphenols, protein, moisture were significant negatively correlated with maturity, and no correlations between species.3. The main fatty acids in olive fruit oils were:oleic acid, palmitic acid, linoleic acid, stearic acid, lignolenic acid, palmitoleic acid, arachidic acid, arachidonic acid, behenic acid, lignoceric acid. The trends of various fatty acids were not exactly same and the same fatty acids were always differences among the different varieties. On the whole, the relative contents of various fatty acids and squalene were:oleic acid and palmitic acid rose after initial decline; palmitoleic acid, linolenic acid, stearic acid, arachidic acid, arachidonic acid, behenic acid, squalene declined after initial increase; linoleic acid stabilized after the first rise; changes in lignoceric acid were great difference among varieties. The correlation analysis showed that there were complex correlations among fatty ascid as well as varieties and maturity. The principal component analysis showed that the 4th maturity was best in most varieties; compared the scores of optimum maturity of each variety and then scored in descending order:Koroneiki, Yuntai, Coratina. Picual, Frantoio, Douguo, White olives, Kalinjot, Ezhi, Pendollino.4. The main phenolic compounds of fresh olives in 10 olive varieties with six maturity were determined and the results as follows:gallic acid, hydroxytyrosol, p-hydroxy benzoic acid, chlorogenic acid, p-coumaric acid, ferulic acid, caffeic acid, benzoic acid, verbascoside, oleuropein, rutin, quercetin. With the maturity increasing, the trends of various polyphenols were not exactly same, but basically showed the following trends: gallic acid, hydroxytyrosol, rutin, oleuropein and quercetin declined with maturity increasing; p-hydroxy benzoic acid, chlorogenic acid, p-coumaric acid, ferulic acid, benzoic acid, caffeic acid first declined and then rising, verbascoside changes were quite different among different varieties. The correlation analysis showed that there were significantly or apparently significantly positive correlations among different compounds; there were no significant or negative correlation between compounds and maturity; the correlation between the compounds and varieties were different in terms of types. The principal component analysis showed that the first maturity was best in most varieties; compared the scores of each variety in optimum maturity and then scored in descending order:Pendollino, Picual, Koroneiki, Ezhi, Kalinjot, White olives, Coratina, Douguo, Yuntai, Frantoio.7. The comprehensive evaluation of olive fruit quality from both the maturity and the varieties, the results were as follows:the 4th maturity was the best one and followed was 5th maturity; the principal component analysis of 34 measured indicators in optimum maturity for each variety showed the orders of quality from high to low:Douguo, Picual, White olives, Yuntai, Ezhi, Koroneiki, Pendollino, Coratina, Frantoio, Kalinjot,... |
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