Bitterness Quality Evaluation Of Fruit From Different Citrus Germplasm Resources And Newhall Navel Orange Harvested In Different Areas

Citrus is one of the major favorable fruit in the world. As the development of economy and improvement of living standard, consumers’demand for the quantity and quality of fruit increased gradually. The bitterness substance is an important component of fruit quality, also has function in health-promotion of human beings. In present study, in order to evaluate the accumulation of bitter substances in differential citrus germplasm and the regulation of environmental factors on it, fruits of 76 citrus germplasms and Newhall navel orange from 16 production areas were selected to detect the content of naringin, limonin and nomilin. The main results were as follows:1. The concentrations of naringin, limonin and nomilin in four different fruit tissues (flavedo, albedo, segment membrane and juice sacs) of 76 citrus species were measured by high-performance liquid chromatography (HPLC). Significant differences were discoverd among the four fruit tissues and the 76 citrus species. In fruit tissue, content of naringin was highest in albedo, followed in turn by segment membrane, juice sacs and flavedo. Contents of limonin and nomilin in tissues showed the same way, segment membrane> albedo> juice sacs> flavedo. In addition, contents of the three bitterness substances in different citrus species ranked in order as:pummelos, grapefruits, hybrids, mandarins, tangerines, navel oranges and common sweet oranges.2. The concentration of bitterness substances in 4 differential tissues were measured in mature Newhall navel orange fruit harvested from 16 production areas. The results showed that the contents of bitterness substrates were affected significantly by the environment. The naringin concentration of Newhall navel orange fruit was the highest (4.57±0.16 mg/g FW) in Baishi of Guizhou province, but the lowest (1.29±0.18 mg/g FW) in Jishou of Hunan province. As for limonin, the highest content (352.99±56.59μg/g FW) was detected in the fruit harvested from Danjiangkou of Hubei province, while the lowest (9.05±2.28μg/g FW) in Yizhang of Hunan province. Besides, content of nomilin in Newhall navel orange fruit from Danjiangkou of Hubei province was the highest (11.51±1.27μg/g FW), while that from Fengjie of Chongqing municipalities was lowest (1.46±0.12μg/gFW).3. Influence of meteorological factors on bitterness substances in citrus fruit was evaluated based on data of the Newhall orange fruit from the 16 production areas. Linear regression showed that the content of naringin was negatively related with rainfall (r=-0.52, P<0.05), the content of limonin was negatively related with temperature (r=-0.65, P<0.05), and the content of nomilin was positively correlated with temperature (r=0.77, P<0.05).