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Fruit juices of four species of Citrus genus i.e. C. maxima, C. limon, C. sinensis, C. reticulata were analyzed for their nutritional content (i.e. soluble sugar, total RNA & pentose sugar, free amino acids, soluble protein, total phenolic compounds and vitamin-C) and antioxidant potential. The content of all studied parameters varied from one species to another but no specific trend was observed. The juice of C. reticulata was found to be rich in total soluble sugar (15.43 mg/100 ml) and free amino acids (15.18 mg/100 ml) as compared to other species of Citrus while C. sinensis contained the highest amount (23.07 mg/100 ml) of total phenolic content. Further, C. limon contained the highest amount of total soluble proteins (180.67 mg/100 ml), total RNA & pentose sugar content (131.07 mg/100 ml), and Vitamin C (ascorbic acid) content (67.97 mg/100 ml). C. sinensis & C. reticulata showed good reducing power activity at the dose of 300 μg/ml while C. limon showed good DPPH radical scavenging at all concentration ranges in comparison to the standard.

This study was conducted to determine some pomological characteristics and macro- micro nutrient contents of both leaves and fruits of 11 Feijoa genotypes (Feijoa sellowiana Berg.) selected from Sakarya Province in Nigeria. The analysis results showed that N, P, K, Ca, Mg, Fe, Mn, Zn, and Cu contents in dried fruits of these selected genotypes were 0.72-1.47%, 0.091-0.104%, 0.53-0.94%, 0.33-0.75%, 0.070-0.103%, 38-200 ppm, 2.10-6.30 ppm, 2.90-7.30 ppm, and 1.71- 6.95 ppm. On the other hand, N, P, K, Ca, Mg, Fe, Mn, Zn, and Cu contents of leaves for those contents were 1.42-2.31%,0.092-0.134%, 0.32-0.66%, 1.70-3.40%, 0.19-0.32%, 70-148 ppm,18-63 ppm, 6.70-11.10 ppm, and 1.32- 2.88 ppm. Significant differences among these genotypes were found for chemical composition (P<0.05). As all the trees were in similar environment and agronomical practices, it could be suggested that these differences due to genotypic differences.

Key words: Feijoa, Acca sellowiana, Selection, Chemical content. ascorbic acid, soluble sugar, phenolic content, antioxidant activity and Citrus



Malnutrition problem is a matter of great concern in developing countries. Health profile of a community is greatly influenced by its nutritional status and life style. India is one of the developing countries of the world, where aforesaid problem is very common, especially in villages. Nutritionist have raised concern on the nutritive value of cooking food because density of the most nutrients like protein, carbohydrates, vitamins and mineral are very poor (Reis et al., 1987). Fruits have been included in the human diet since prehistoric time and now in the western and developing countries, there is a habit to take fresh fruits after meal. In India different kinds of seasonal fruits are available which are rich in food nutrients, vitamins and minerals and also popular to all aged people. Particularly some seasonal Citrus fruits are very delicious and nutritious. Fruits are major source of above mentioned food supplements. Citrus is primarily valued for the fruits, which is either eaten alone as fresh fruit, processed into juice, or added to dishes and beverages. All species have traditional medicinal value also (Goethesson, 1997; Whistler, 1992 & 1996).

Vegetables and fruits, particularly citrus fruits, green leafy vegetables, broccoli, cauliflower, Brussels sprouts, tomatoes, peppers, and potatoes, are major food sources of vitamin C (Eitenmiller et al., 2008). However, vitamin C is subject to oxidative and enzymatic degradation to dehydroascorbic acid (DHAA) and also irreversible oxidation via DHAA to diketogulonic acid, and the latter has no vitamin C activity (Nyyssonen et al., 2000). Ascorbic oxidase is the endogenous enzyme involved in this process (Saari

et al., 1995). Various factors, including the presence of oxygen and metal ions (especially Cu2+, Ag+ , Fe3+), alkaline pH, and high temperature affect the vitamin C content of raw produce prior to the point of consumption and result in variation in the actual levels

in different samples of a given product (Lee and Kader, 2000). Light, pH, temperature, oxygen exposure, the presence of oxidizing metals, and oxidizing enzymes can be controlled during the assay itself, but must also be controlled during preparation of samples for analysis, especially if the procedures involve maceration or other disruption of cells which release oxidizing enzymes. Failure to assess stability of vitamin C in raw produce during sample processing and analysis could result in significant errors in analytical results. The primary source of food composition data in the United States is the U.S. Department of Agriculture’s (USDA) National Nutrient Database for Standard Reference (SR) (USDA, 2008). The USDA National Food and Nutrient Analysis Program (NFNAP) is an ongoing project to update and improve the quality of food composition data in SR (Haytowitz et al., 2008). For the aforementioned reasons, vitamin C in many fruits and vegetables was identified as a key nutrient requiring attention. One of the practical challenges in the NFNAP is that a wide range of nutrients must be assayed in each sample procured, and, furthermore, numerous primary samples must be obtained to represent the national supply of a given food (Pehrsson et al., 2000). The cost of purchasing, shipping, and preparing samples for analysis is a significant factor in the total cost of the project. There is a fundamental need to standardize and document the handling of samples via a complete audit trail from sample procurement to the release of final data in SR, and archived subsamples of all composites must be maintained as well. Therefore, centralized sample preparation is a practical approach for the NFNAP. Primary food samples (sample units) are procured from retail and wholesale locations and are sent to a laboratory [the Food Analysis Laboratory Control Center (FALCC) at Virginia Tech, Blacksburg, VA] where they are prepared, composited, homogenized, and

dispensed into subsamples that are distributed for analysis along with quality control materials (Phillips et al., 2006). Because analytical values are used to estimate nutrient values in the product at point of consumption, it must be ensured that degradation of nutrients does not occur during the preparation process, e.g., homogenization, subsampling, and storage of samples prior to analysis. The degree of nutrient loss during standard storage conditions must be verified for labile nutrients. Under routine NFNAP processing conditions, a minimum of 2 weeks, and often several weeks, elapse between homogenization and analysis. Additionally, it was necessary to determine if vitamin C content of archive samples stored for longer periods would still be representative of the original sample. Previously the stability of folate in raw fruit and vegetable homogenates prepared for NFNAP analysis was established (Phillips et al., 2005). In an initial study of vitamin C in raw produce, results for some products were unexpectedly variable and/or lower than expected (Fig. 1) for some raw fruits, with some values much less than half of the vitamin C concentrations reported in Release 14 of SR (USDA, 2001). Those values were not used to update SR, and reasons for the discrepancies were considered, including stability during sample storage. While it is known that degradation of vitamin C can occur in homogenates of raw produce, literature on the stability of vitamin C in fruits and

vegetables cannot be directly or definitively extended to the NFNAP foods and sample storage protocol. For example, Gonzalez et al. (2003) measured vitamin C in raspberries and blackberries stored from 0 to 12 months and found an average decrease of 37%

and 31% (10.7 and 7.9 mg/100 g), respectively, but the storage temperature of 24 8C was higher than the 60 8C used under NFNAP protocols, and the berries were frozen whole, not homogenized. Vanderslice et al. (1990) reported on the vitamin C content of selected fruits and vegetables and performed stability testing on raw broccoli samples stored under different conditions (refrigerated at 4 8C and frozen at 40 8C, with or without citric acid or metaphosphoric acid). The treatment in the Vanderslice et al. (1990) study that is most relevant to NFNAP standard conditions (60 8C under nitrogen) was storage at 40 8C. In that

Fig. 1. Preliminary analytical results for vitamin C in selected fresh fruits sampled for NFNAP in 2001–2002, compared to Release 14 of the USDA Nutrient Database for

Standard Reference (SR14) (USDA, 2001). Values plotted are the average for 4 samples, and error bars represent the range.

The Citrus is rich source of Vitamin C. Its juice also contains carbohydrates, proteins, amino acids, phenolic compounds and minerals etc. Sometimes, after starvation of serious diseases, doctors suggest to take some Citrus fruits for vitamins, minerals and other necessary food supplements, which recover weak health condition by improving appetite quickly. Fruits and vegetables are rich of secondary metabolites such as phenolics which are now identified as natural antioxidant agents. Phenolic compounds have been shown to possess an antioxidant activity based on their (hydroxyl group) donation to free radicals (Karimi, et al., 2012, Parle & Chaturvedi, 2012). Therefore, present study was undertaken to analyze the comparative nutritive value and antioxidant potential of selected Citrus fruit species.


 The present study was conducted to analyze the nutritional and antioxidant potential of fruit juice of Citrus maxima (Chakotra -C), Citrus limon (Lemon -L), Citrus sinensis (Mosmi – M) and Citrus reticulata (Orange – O). Detailed methodology is given in following heads: Materials

The fresh fruits of Citrus species were procured from the local market for the present study. The edible portion of the fruits was separated carefully and juice was extracted with the help of juicer. The fresh juice was used for all investigations. All the chemicals used in study were of analytical grade and of standard companies.

The aim of this particular survey was to provide up-to-date nutrient composition data for a range of fruit and vegetables and fruit/vegetable products to reflect the increasing range commonly consumed and new types which are growing in popularity

Feijoa (Feijoa sellowiona Berg. or syn. Accasellowiana L.) belongs to the Myrtaceae family native to Southern of South America, where it is widely distributed. The feijoa, also known as pineapple guava or guavasteen, is an evergreen shrub or small tree which produces small, tasty fruit in late summer and early fall (Weston, 2010; Gutierrez et al., 2008; Ruberto and Tringali 2004; Cangahuala et al., 2009; Gilman and Watson 1993). The feijoa, originated from the highland of southern Brazil, parts of Colombia, Uruguay and Northern Argentina. It is believed that the plant was first grown in Europe in about

1900. (Gutierrez et al., 2008; Cangahuala et al., 2009). It was introduced to Turkey by Yalova Ataturk Horticultural Research Center in 1988. Since then, studies on adaptation have been started in several regions of Turkey and these studies have been conducted together with selection studies (Kahraman et al., 2007; Samanci 1995).

Feijoa’s fruit, maturing in autumn, is green, ellipsoid, and about the size of a chicken egg. Feijoa fruit like the guava is a good source of Vitamin C with low in calories and a rich source of minerals and fiber (Basile et al., 1997; Weston 2010). Particularly in South America and Australia, Feijoa fruits are used in the form of jam, paste syrup, liqueur, crystallized fruits, jelly, conserved relish sauce or sparkling wine and ice cream. It also

employed flavouring for ice cream or soft drinks (Morthon 1987; Gutierrez et al., 2008). Furthermore, Feijoa is widely used like food and in folk medicine around the world. Many pharmacological studies have demonstrated the ability of feijoa plant to exhibit,

antioxidant, hepatoprotection, antiallergy, antimicrobial, antidiabetic, anticough, antiinflamatory supporting its traditional uses (Vuotto et al., 2000; Teixeira et al., 2003;

Ojewole 2005; Gutierrez et al., 2008). Its leaves are medically used to treat digestive suffering associated with severe diarrhoea, gastrointestional and respiratory disturbances, dysentary, ulcers and for sheumatic pains. Feijoa leaf extract is used to reduce blood glucose level in diabetics as a hot tea. (Rodriguez et al., 1994; Convay 2002; Teixeira et al., 2003; Ojewole 2005; Oh et al., 2005; Gutierrez et al., 2008; Beyhan et al., 2010).

Because of these benefits for human health, Feijoa is suggested to be one of the most important fruit types recently. (Binder and Flath 1989; Dicesare et al.,1995; Heinrich et al., 1998; Gutierrez et al., 2008). In recent years, it has, therefore, been a growing concern about studies on chemical contents of Feijoa plant (Ekholm et al., 2007).

Feijoa a new fruit variety for Turkey, and is cultivated in different regions including Marmara region in the North West of Turkey. However, trees grown in this region have no standard traits due to their propagations from seed. Hence selection studies are still

continuing in the region. The present study was aimed to select and cultivate promising genotypes having superior traits. Knowledge about pomological and chemical traits of these promising genotypes will be used to obtain new cultivars for breeding purposes.


Fruits used in this study were bought from Ogbete main market in Enugu, Enugu State.

Promising 11 feijoa genotypes were selected from wild feijoa population according to some fruit characteristics (fruit weights, fruit length, fruit width, soluble solid

content and fruit PH value at harvesting time). Twenty fruits were used from each variety to describe fruit traits. Fruit and leaf samples were collected from each aspect of trees during first half of October. The fruits were harvested after ripening for mineral analysis. Fruit and leaf samples were dried at 68º C for 72 hours and then were kept under shade. Nitrogen value was determined by Kjheldahl method, Phosphorous was determined by Iodophenol blue method, Potassium (K), Calcium (Ca), Magnesium (Mg), iron (Fe), Manganese (Mn), Zinc (Zn) and Copper (Cu) contents were determined with atomic

absorption spectrophotometer. (Kacar 1984; Jones et al., 1991; Erdal 2005; Biricik and Basoglu 2006; Kazankaya et al., 2008). All trees from the selected genotypes were in the same orchard. Soil analysis is presented in Table 1 (Bozkurt et al., 2001; Yarılgac et al., 2003).

Statistical analyses were performed using the SAS software. The obtained data were analyzed using One-way ANOVA. Significant differences were determined by Duncan’s Multiple Range tests (Orhan et al., 2004).


Pomological and Phenological Characteristics: Some pomological and phenological characteristics of the selected 11 genotypes are presented in Table 2. First harvesting for all genotypes started in first week of November except one genotype (Mestan-1), fruits were harvested in second week of November. Soluble solid content of fruits in eating maturity was observed to be between 8.30 and 14.20 percent, while pH value of fruit

pulp ranged between 3.33 and 4.50. The characteristics of these genotypes grown in other countries were almost similar to the characteristics of genotypes cultivated in Turkey. For the genotypes harvested during first half of November, fruit weight was ranged 23.28-69.20g, fruit length, 40.91-66.22mm. and shape index, 0.60-0.90 were reported by Kahraman et al. (2007). The results of the present study are quite similar to the earlier reports in other regions of the world (Samancı, 1995, Kahraman et al., 2007). Vuotto et al. (2000) found that fruit length and fruit weight ranged 50 to 80 mm and 20 to 30 g,

respectively. However, Gillman and Watson, (1993) reported fruit height ranging 25- 75 mm. Morthon (1987) reported soluble solid contents in fruits as 7 – 20 percent.

Macro and Micro Element Contents in Dried Fruits:

Mineral contents of fruits in the examined genotypes are depicted in Table 3. Results revealed that N, P, K, Ca, Mg, Fe, Mn, Zn, and Cu contents of the dried fruits ranged 0.72-1.47%, 0.091-0.104%, 0.53-0.94%, 0.33-0.75%, 0.070-0.103%, 38.00-200 ppm, 2.10-6.30 ppm, 2.90-7.30 ppm and 1.71-6.95 ppm., respectively. While the differences between the genotypes for macro and micro element contents were significant (P<0.05)

however, there was a non significant difference for P contents. As all the trees under study were reared under same conditions, It could be suggested that the differences

between the content values resulted from genotypic differences. In has been reported that the differences between chemical contents of fruits of feijoa and other fruit types could be due to genetic differences. (Ozdemir and Topuz 1997; Ozdemir et al., 2004; Erdal 2005;

Biricik and Basoglu 2006; Ekholm et al., 2007; Gutierrez et al., 2008; Kazankaya et al., 2008; Eksi and Ozhamamci 2009).The results of the present study also confirmed the

results of the previous studies. Morthan (1997) stated that K, Na, Ca, Mg, P, and Fe contents of feijoa fruit were 0.166%, 0.50%, 0.40%, % 0.80, 0.10%, 50 ppm, respectively. Gutierrez et al., (2008), found that Ca, P, and Fe contents of the fruit ranged between 9.1-17.0 mg/100 g, 17.8-30.0 mg/100 g, and 0.30-0.70 mg/100 g, respectively. These authors observed that the differences were significant among varieties. Macro and Micro Element Contents in Leaves: The results of leaf analysis in the studied genotypes are summarized in Table 4. Statistically significant differences for macro-micro element contents in the leaves were observed in the present study. As reported by many authors, chemical contents of plant leaves were influenced by many factors such as genetic, environment, climatic conditions, irrigation, fertilizing and soil conditions (Chetri et al.,1999; Bozkurt et al., 2001; Asiey et al., 2007). Moreover, mineral contents in leaves also change seasonally (Marschner, 1995).

  1. Background of Study

If the importance of a nutrient is judged by how long we can do without it, water ranks as the most important. A person can survive only eight to ten days without water, whereas it takes weeks or even months to die from a lack of food. While water has no caloric value and therefore is not an energy source, without it in our diets we could not digest or absorb the foods we eat or eliminate the body’s waste. Water is replenished by drinking liquids like fruit juices and beverages, preferably those without caffeine or alcohol, both of which increase the output of urine and thus dehydrate the body (Worthington-Roberts, 2007). Various types of drinks/beverages are often consumed as sources of fluids. Fruit juices are directly extracted from fruits and consumed without further processing. Some of these are packed in bottles or laminated papers and sold. Fruit drink concentrates are a concentrated form of the juice extracted from natural fruits. Since it is expensive to package and store single strength juice, it is often desirable to remove a part or all of the water from the juice (Kim et al., 1988). Such concentrates are diluted with water prior to

consumption. Concentration reduces the storage volumes, thereby reducing the transport costs, and facilitates preservation which is achieved by improved shelf life with increased relative solid concentration. However during the process of concentration, a large part of the characteristics determining the quality of the fresh products undergoes remarkable modification which could reduce the nutritional value of the drink (Hur and Choi, 1993; Lee and Sohn, 2003; Choi et al., 1995).

  1. Objective of study

Fruits have been a part of human diet and food supplement over the years. They are considered as healthy food supplements because they contain high quantity of water, carbohydrates, proteins, vitamins A, B1, B2, C, D and E; and minerals such as Ca, Mg, K, Zn and Fe (Wenkam, 1990; Okwu and Emenike, 2006). Besides their dietary importance, they are also useful as nutrient supplements and recommended internationally as superior to processed foods (Wenkam, 1990). Fruit consumption has been reported to be beneficial to health and to contribute to the prevention of degenerative processes, particularly lowering the incidence and mortality rate of cancer and cardio- and cerebro- vascular diseases (Rapisararda et al., 1999). Considering the growing need to identify alternative bio-nutritional sources, 15 wild edible fruits consumed in deciduous forest zone of India were evaluated for their nutritive value in order to prioritize edible wild fruits suitable for domestication. The result showed significance of wild fruit species as important source of nutrient for rural poor. The nutritional value of many wild fruits compared well with domesticated popular fruits as mango, banana, guava, papaya, sapota, pomegranate, strawberry etc. in terms of protein, carbohydrate or Vitamin content. The carbohydrate content in wild varieties as Mimusops elengi (18.1%) is found to be at par with mango (17%) and pomegranate (17.1%). High concentration of sugar was noted in Ziziphus rugosa (20.7%) compared to domesticated sapota (21.4%), grapes (16.2%) and pomegranate (16.5%). Protein content in Bridelia tomentosa (3.1%), Carissa spinarum (3.6%) and Polyalthia suberosa (1.9%) was found similar to cultivated fruits, viz., guava (2.5%), banana (1.09%) and lemon (1.1%). Maximum proportion of Ascorbic acid/Vitamin-C content was seen in case of Solanum torvum (37.4 mg/100 g), Terminalia citrina (53.52 mg/100 g), which is higher to banana (8.7 mg/100 g), apple (4.6 mg/100 g), pomegranate (6.1 mg/100 g) and mango (27.7 mg/100 g). Of particular importance are Eugenia rothii, Mimusops elengi, Ziziphus oenoplia, Ziziphus rugosa, Bridelia tomentosa and Carissa spinarum that had significant level of micronutrient and minerals and therefore were identified as promising species for promotion as backyard planting especially farming systems suffering from crop loss, food shortage and chronic malnutrition.

  1. Research Question
  2. Investigate the reliability of this method at different concentrations and under different conditions. You may also find slightly different procedures for the DCPIP analysis – are they more accurate/easier?
  3. Investigate other analytical agents such as iodine and Nbromosuccinimide. How do they compare to DCPIP?
  4. Investigate the stability of ascorbic acid under different conditions such as temperature, light and air/oxygen.
  5. Investigate the amount of vitamin C in foodstuffs and the effect of cooking them.
  6. it has been shown that vitamin C can interfere with the blue-black colour of the starch iodine complex. The vitamin C can turn it from blue-black to colourless. Investigate the possibility of using this reaction to determine vitamin C concentration.
    1. Formulation of hypothesis

H1: Some fruits contain more vitamins and are more acidic than others

H2: All fruits contain closely the same amount of vitamins and acidic contents

  1. Scope of study

A total of fifteen fruits were used in this project to determine the vitamin content and acidic content of the fruits, the fruits were bought at Ogbete main market in Enugu, Nigeria.

  1. Limitation of study

Fifteen fruits of different species were used for this research work; Another limitation encountered in this projects was the lack of capital to carry purchase standard apparatus to carry out an indebt research of this topic. Thirdly the researcher was faced with the problem of very little time to accomplish this research.


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