| Summary: | 碩士 === 國立中興大學 === 食品科學系 === 92 === Abstract
Citrus fruit has about 37,000 hectares of planting area and 450,000 tons of annual production in Taiwan, is one of the Taiwan’s most important economic fruit. Citrus pulp and peel are both rich in functional constituents, such as vitamin C, flavonoids, phenolic acids, pectic substances, carotenoids, monoterpenes, glucarates, phytosterols, folic acid, and so forth. These components provide many kinds of physiological effects, such as antioxidation, antitumor, antimocrobial, diuresis ,anti-inflammation, analgesia, sedative, toxicide, inhibitory of blood clots , reducd the risk of cardiovascular and enhanced immune system etc. In this study, the focus on eight of the most productive types of citrus in Taiwan, such as Ponkan, Tonkan, Murcott, Wendun, Peiyou, Kumquat, Liucheng and lemon. Samples of each were taken from the location of producing. Analysis of the pulp and peel for the functional compounds were carried out.
Concerning the investigation of citrus pulp, the content of totalphenols distributed from 0.502-1.284 g/100 g . Tonkan, Lemon and Wendun contained the most. The content of total flavonoids distributed from107.02-275.30 mg/100g. Liucheng and Lemon contained the most. Flavonoids were divided into three classes : flavanone, flavone and flavonol. Hesperidin, narigin and neohesperidin were three kinds of flavanones in citrus fruit. Hesperidin, which was the highest concentration in citrus pulp, with the content of 4.46-94.16 mg/100g. Diosmin, luteolin and sinensetin were three kinds of flavone compounds in citrus fruit. Diosmin, which exhibited the highest concentration in citrus pulp, with the content of 0.71-8.53 mg/100g. Rutin, quercetin and kaempferol were three kinds of flavonols in citrus fruit. Kaempferol, which showed the highest concentration in citrus pulp, with the content of 0.07-15.29 mg/100g. There were many kinds of phenolic acids finding in citrus pulp, but all the content of compounds showed more lower. Citrus fruit possessed fairly high concentration of vitamin C, especially in Tonkan and Lemon, which contained 126.88-146.83 mg/100g in pulp. Pectic substances, which had a rate of 0.49-0.93 g/100g in citrus pulp, were richer than other fruits, and the content of total carotenoids distributed from 0.036 mg/100g to 0.743 mg/100g. Kumquat showed the highest content. Lutein, zeaxanthin, β-cryptoxanthin and β-carotene were four kinds of carotenoids, and the concentrations in citrus pulp were relative low.
The investigation of citrus peel, we found that the concentration of functional ingredients was higher. The concentration of total phenols in citrus peel distributed from 4.953 g/100g to 6.988 g/100g, which was 4-5 times that in citrus pulp. The content of total flavonoids distrubuted from 521.79-1248.40 mg/100g , Wendun and Peiyou showed the highest ones, containing 1248.40 mg/100g and 1118.42 mg/100g respectively. Three classes of flavonoids in citrus fruits, which are flavanone, flavone and flavonol. Flavanone occurred in the highest content. Hesperidin, naringin and neohesperidin are three kinds of flavanones in citrus fruit. Hesperidin occurs in a fairly high concentration in citrus peel, 202.39-511.25 mg/100g. Wendun and Peiyou contained much higher content of naringin than other citrus, 639.33及683.54 mg/100g。. Diosmin, luteolin and sinensetin, three kinds of flavone compounds, diosmin appeared to be the highest one, 2.78-14.23mg/100g. Rutin, quercetin and kaemperol, three kinds of flavonol occur in similar content in citrus peel, 1.11-6.20 mg/100g, 3.37-9.96 mg/100g and 1.85-8.72 mg/100g respectively. The content of phenolic acid in citrus peel was higher than that in citrus pulp. Chlorgenic acid and coumaric acid appear to be the highest, while ferulic acid and sinapic acid were followed, and caffeic acid was the lowest one. The content of vitamin C in citrus peel was 2 times higher than that in citrus pulp, 264.27-354.11 mg/100g. Pectic substances occured at 0.74-2.31 g/100g in citrus peel, a rate which was 1-2.5 times higher than that in citrus pulp. Liucheng and Murcott showed the highest content, with the content of 0.609 and 0.611 mg/100g, respectively. Four kinds of carotene, which were lutein, zeaxanthin, β-cryptoxanthin and β-carotene, β-cryptoxanthin and β-carotene exhibited fairly high content in citrus peel.
According to the results in our studies, citrus fruit in Taiwan was rich in functional constituents that possessed many kinds of healthy functions. The results provide great information in citrus fruit marketing and fresh to eat citrus fruit. Moreover, awareness of the high composition of functional components in citrus peel, especially flavonoids, could have applications in the health food and cosmetics. Thus, it will help to provide a larger development for the production of citrus fruit in Taiwan.
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