Study On The Fruit Quality Changes During Fruit Development Of Lane Late And Cara Cara Navel Orange

China is an essential origin of Citrus spp and riches in different kinds of citrus germplasm resources.However,there are still some problem exist in citrus industry,such as lacking of variety diversity,too many medium-maturing varieties,short of good quality and late-maturing oranges,etc.To adjust production structure of citrus industry in our country,in recent years,several late-maturing varieties were successfully bred or introduced from other countries.So far,the studies on the adaptability are rare,especially the fruit quality of these late-maturing varieties.In this paper,we used the fruit flesh and pericarp of Citrus sinensis Osbeck cv.Lane late and Citrus sinensis Osbeck cv.Cara cara navel orange as experiment materials.The content of major sugars,organic acids,Vc,carotinoid and cellulose in the fruits was analyzed.The major results are as follows:1.Lane late and Caca cara navel orange have the same fluctuation profiles in sugar content,which were both increasing with the fruit developing.The total sugar content was 128.44 mg/g and 141.41mg/g,respectively.Saccharose increased the fastest and eventually reached a higher level than fructose,and the glucose level was even lower.But there was no significant difference between them.The content of soluble solids increased gradually with the fruit developing.It was 13.8%in ripe Caca cara navel orange,while 11.2%in ripe Lane late.The content of Vc was declined in harvest time.It was 52.30 mg/100 mL in ripe Caca cara navel orange,while 36.35 mg/100 mL in ripe Lane late.2.The components of titratable acid in both varieties decreased gradually with the fruit developing.It was 0.93%in ripe Caca cara navel orange and just 0.51%in ripe Lane late.Among the different components of acid,the citric acid content is about 79 %-88%of the total acid content.There are little malic acid and quinic acid as well.3.The fruit coloration changed dramatically in the middle-stage of fruit development. The color of Lane late and Caca cara navel orange fiuit turned yellow green to orange. The total carotinoid in pulp and peel continued to rise in this developmental stage.The major component of carotinoid was Lutein in the fruit of Lane late navel orange,which was 55%-90%of the total carotinoid content.The content of Lycopene was the highest in Caca cara navel orange fruit,followed with lutein andβ-carotene.4.During the fruit developmental stage,the proto pectin decreased while the water soluble pectin increased.The content of proto pectin and water soluble pectin was 3.52 mg/g and 2.28 mg/g respectively in ripe Lane late,and was 6.24 mg/g and 1.07 mg/g respectively in ripe Caca cara navel orange.They are both higher in the peel than in the pulp in the two varieties.The cellulose changing trends between the pulp and the peel were opposite.It was increased in the pulp while decreased in the peel with the development of the fruit.