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Total, insoluble and soluble dietary fiber contents of Indian fruits
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JOURNAL OF FOOD COMPOSITION AND ANALYSIS
Journal of Food Composition and Analysis 16 (2003) 677–685 www.elsevier.com/locate/jfca
Original Article
Total, insoluble and soluble dietary fiber contents of Indian fruits Punna Ramulu*, Paruchuri Udayasekhara Rao Food Chemistry Division, National Institute of Nutrition, Indian Council of Medical Research, Jamai-Osmania (P.O), Hyderabad 500 007, India Received 30 September 2002; received in revised form 21 February 2003; accepted 13 April 2003
Abstract This work provides new data on total (TDF), insoluble (IDF) and soluble (SDF) dietary fiber contents of Indian fruits, which play an important role in human nutrition. Twenty-five common fruits and nine mango varieties were analyzed for their TDF, IDF and SDF contents by enzymatic and gravimetric method of AOAC. Among the fruits, the TDF and IDF contents ranged between 0.6 and 0.3 g% in watermelon and 10.9 and 9.1 g% in sapota, respectively. The SDF content ranged from 0.3 g% in watermelon to 2.4 g% in fig. The SDF as percentage of TDF was low in pear (7.0%) and high in sweet lime (51.8%), but in general, the majority of the fruits had 30%. In mango varieties the TDF and IDF contents were low in panchadarakalasa (1.3 and 0.5 g%) and high in banganapalli (3.0 and 1.5 g%), respectively. The SDF content was low in dashehari (0.7 g%) and high in eruman (1.6 g%). The SDF as % TDF ranged between 46.9% in dashehari and 61.5% in panchadarakalasa, but most of the mango varieties had around 50% of their TDF as SDF. Results indicate that fruits such as fig, mango, orange, papaya and sweet lime are rich sources of SDF, the component of TDF associated with a number of health benefits. The TDF contents of fruits analyzed in the present study were higher than their crude fiber content. r 2003 Elsevier Ltd. All rights reserved. Keywords: Fruits; Mango varieties; Crude fiber; Total dietary fiber; Insoluble dietary fiber; Soluble dietary fiber
1. Introduction Dietary fiber (DF) plays an important role in decreasing the risks of many disorders such as constipation, diabetes, cardiovascular diseases (CVD), diverticulosis and obesity (Spiller, 2001). *Corresponding author. Tel.: +91-40-7008921; fax: +91-40-7019074. E-mail address: p [email protected] (P. Ramulu). 0889-1575/$ - see front matter r 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0889-1575(03)00095-4
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Plant foods are the only sources of DF. All the fractions (cellulose, lignin, hemicellulose, pectins, gums and mucilages) of DF are the major constituents of plant cell wall (Selvendran, 1984; Selvendran & MacDougall, 1995). Dietary fiber is subdivided into Insoluble (IDF) and soluble (SDF) dietary fiber depending on their solubility in water. However, the DF can be grouped into two major types (a) soluble/viscous/fermentable and (b) insoluble/nonviscous/slowly fermentable (Roberfroid, 1993). Recently, FAO/WHO discussion document on carbohydrates recommended dropping the terms ‘‘soluble’’ and ‘‘insoluble’’ fiber (FAO, 1998). The physiological effects of total dietary fiber (TDF), in the forms of insoluble and soluble fractions of foods, have a significant role in human nutrition (Schweitzer & Edwards, 1992). Indian diets predominantly consist of a variety of plant foods such as cereals, pulses, green leafy vegetables (GLV), roots, tubers, other vegetables, fruits, oil seeds, spices and condiments. Fruits are consumed in various forms like fresh, dried, frozen or canned (Marlett, 1992). The polysaccharides comprising a major part of DF in fruits and vegetables are beneficial to healthy human volunteers, since the consumption of fiber lowers plasma cholesterol levels (Jenkins, Kendall, & Ransom, 1998). Gillman et al. (1995) reported protective effect of fruits and vegetables against the development of stroke in men. Addition of fruits and vegetables to the regular diet of infarcted survivors resulted in a decreased mortality and subsequent infarctions (Singh, Niaz, Ghosh, Singh, & Rastogi, 1993). Therefore, the dietary fiber may play a major role in determining the health and disease conditions of different population groups. The data on DF content and its components in fruits are not available in India. The dietary reference value (DRV) for the DF has not been prescribed so far, either in India (Indian Council of Medical Research, 1998), or in most other countries. Some organizations suggested 10 g DF/1000 kcal as an interim recommendation (Mori et al., 1996) and Food and Nutrition Board (2002), Institute of Medicine, USA recommended approximately 14 g TF/ 1000 Kcal. No systematic studies are available so far in this regard. Presently, the food composition tables give crude fiber (CF) content but not DF content of foods in India (Gopalan, Ramasastri, & Balasubramanian, 2000). Moreover, the methodology for the determination of fiber content of foods has changed from time to time from a chemical method (Van Soest & Wine, 1967) to chemical and gravimetric method (Southgate, 1969) to an enzymatic and gravimetric method (Prosky, Asp, Schweitzer, DeVries, & Furda, 1988). The methodology for the enzymatic and gravimetric determination of DF content of foods simulates the human physiological digestive process and hence gives more accurate/ relevant values. Therefore, it is necessary to adopt a suitable method for the determination of TDF, IDF and SDF contents of foods, which mimics the human physiological conditions. Our earlier studies at National Institute of Nutrition for determining the TDF, IDF and SDF content of cereals and pulses demonstrated that most of the cereals are a rich source of IDF, except wheat, which is rich in both IDF and SDF. Pulses are good sources of IDF as well as SDF (Ramulu & Udayasekhararao, 1997). Since a variety of health benefits have been attributed to the consumption of fruits and as there are no data available on TDF, IDF and SDF contents of most of the commonly consumed fruits in India, the present study has been undertaken.
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2. Materials and methods 2.1. Collection of samples Twenty-five different types of fruits (amla, apple, banana, cherry, custard apple, fresh dates, fig, grape, guava, jackfruit, jambu, mango, muskmelon, orange, papaya, peach, pear, pineapple, plum, pomegranate, sapota, strawberry, sweet lime, watermelon and zizyphus) were purchased from local markets. Each variety of fruit was collected from four different places to assess the variation in their TDF, IDF and SDF contents. Nine authentic mango varieties (banganapalli, dashehari, eruman, neeligova, panchadarakalasa, peddarasaloo, rumani, totapuri, and vikarabad mahamooda) were obtained from Acharya N.G. Ranga Agricultural University, Rajendranagar, Hyderabad, India. Two pickle mango varieties (small and big) were also collected from markets. 2.1.1. Samples preparation Fresh fruits were cleaned with water and external moisture wiped out with a dry cloth. The edible portion of the individual fruits was separated, weighed and homogenized thoroughly in a mixer and a known weight of the sample was quantitatively transferred into 500 ml round bottom flasks (glass) and lyophilized. Freeze-dried sample was extracted with diethyl ether to remove the fat content. The total soluble free sugars present in the sample were extracted with 80% hot ethanol. The sample was rinsed with acetone to remove any traces of moisture from the sample and finally, dried in a hot air oven at 50 C for 1 h. The dried samples were then powdered in cyclotech mill using 100-mesh size to get a fine powder. 2.2. Determination of TDF, IDF and SDF Moisture and fat free samples were analyzed for their TDF, IDF and SDF contents by enzymatic and gravimetric method of the Association of Official Analytical Chemists (AOAC) (Prosky et al., 1988), using TDF-100 kit obtained from Sigma chemical company, USA. Along with the test samples, blank and reference samples were also analyzed simultaneously in duplicate for comparison. TDF, IDF and SDF contents of the various fruits analyzed were calculated and expressed on fresh weight basis. 2.2.1. Data analyses The data generated on TDF, IDF and SDF contents of the commonly consumed fruits have been evaluated by parametric tests for statistical significance (Visveswara Rao, 1996).
3. Results and discussion 3.1. TDF, IDF and SDF contents of fruits Table 1 gives the moisture, CF, TDF, IDF, SDF and SDF expressed as % of TDF, contents of common Indian fruits. Among the fruits, the moisture content was low in dates (fresh) (18.8 g%),
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Fruit common name (Botanical name)
Moisture (g/100 g)
CF (g/100 g)a
TDF (g/100 g)
IDF (g/100 g)
SDF (g/100 g)
SDF as % TDF
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Watermelon (Citrullus vulgaris) Muskmelon (Cucumis melo) Orange (Citrus aurantium) Grapes (Vitis vinifera) Cherry (Prunus cerasus) Peach (Amygdalis persica) Banana (Musa paradisiaca) Mango (Mangifera indica) Strawberry (Fragaria vesca) Papaya (Carica papaya) Sweet lime (Citrus sinensis) Pomegranate (Punica granatum) Pineapple (Ananas comosus) Plum (Prunus domestica) Apple (Malus sylvestris) Jackfruit (Artocarpus heterophyllus) Jambu (Syzygium cumini) Zizyphus (Zizyphus jujuba) Pear (Prunus persica) Fig (Ficus carica) Custard apple (Anona squamosa) Amla (Emblica officinalis) Dates (fresh) (Phoenix dactylifera) Guava (Psidium guajava) Sapota (Achras sapota)
96.470.08 94.670.24 88.470.37 85.170.74 92.270.70 88.270.84 81.171.54 79.973.76 92.970.74 77.873.53 91.170.29 81.370.48 86.070.60 85.77.0.44 86.470.41 74.070.47 77.170.55 84.071.63 85.471.03 75.470.88 76.772.54 80.970.29 18.871.37 81.271.03 74.470.68
0.2 0.4 0.3 0.9 0.4 1.2 0.4 0.7 1.1 0.8 0.5 2.1 0.5 0.4 1.0 1.1 0.9 — 1.0 2.2 3.1 3.4 3.7 5.2 2.6
0.670.02 0.870.01 1.170.03 1.270.06 1.570.03 1.670.04 1.870.12 2.070.19 2.370.11 2.670.08 2.770.06 2.870.11 2.870.13 2.870.07 3.270.21 3.570.08 3.570.02 3.870.37 4.370.25 5.070.21 5.570.20 7.370.10 7.770.46 8.570.44 10.970.44
0.370.01 0.570.01 0.670.03 0.870.04 0.970.03 1.170.02 1.170.06 1.070.10 1.670.08 1.370.05 1.370.03 2.370.07 2.370.12 1.770.05 2.370.19 2.170.13 2.670.04 2.870.22 4.070.23 2.670.09 4.070.15 5.870.10 6.970.46 7.170.40 9.170.38
0.370.01 0.370.01 0.570.03 0.470.02 0.670.03 0.570.03 0.770.06 1.070.10 0.770.04 1.370.04 1.470.06 0.570.06 0.570.03 1.170.03 0.970.05 1.470.05 0.970.02 1.070.17 0.370.03 2.470.17 1.570.08 1.570.06 0.870.06 1.470.01 1.870.11
50.070.86 37.570.77 45.570.97 33.370.44 40.071.76 31.371.76 38.971.20 50.071.81 30.470.99 50.070.86 51.871.47 17.871.60 17.870.74 39.370.29 28.171.48 40.072.35 25.770.74 26.372.21 7.070.49 48.071.68 27.370.10 20.570.85 10.471.07 16.570.60 16.571.26
TDF: total dietary fiber; IDF: insoluble dietary fiber; SDF: soluble dietary fiber. No. of samples: four in duplicate determinations for each fruit. a CF: crude fiber values are taken from ‘‘Nutritive Value of Indian Foods’’ (Gopalan et al., 2000).
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Table 1 Moisture, crude fiber, total, insoluble and soluble dietary fiber contents of fruits (mean7s.e.)
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and high in watermelon (96.4 g%). The TDF and IDF contents of the fruits ranged between 0.6 and 0.3 g% in watermelon and 10.9 and 9.1 g% in sapota, respectively. The SDF content ranged from 0.3 g% in watermelon to 2.4 g% in fig. The SDF as % of TDF was low in pear (7.0%) and high in sweet lime (51.8%). Interestingly, the majority of the fruits had 30% of TDF as SDF. The SDF expressed as % of TDF was around 50% in fig, mango, orange, papaya, sweet lime and watermelon indicating that these fruits are rich in SDF. Foods high in SDF content, such as fenugreek (Al-Habori & Raman, 1998), guar gum, oat and psyllium are known for their hypoglycemic and hypocholesterolemic effects in experimental animals as well as in humans (Lairon, 1996). Though fruit consumption in India is meager in quantitative terms, it is a good source of SDF. Thus, the inclusion of fruits rich in SDF content in the regular diet may be beneficial. Both American Dietetic Association (ADA) and Dietary Guidelines for Americans recommended the inclusion of a variety of grains, vegetables and fruits for an active and healthy life (Johnson & Kennedy, 2000). A position statement announced recently by the ADA mentions that the public should consume adequate amounts of dietary fiber from a variety of plant foods (Marlett, McBurney, & Slavin, 2002). The source of daily TDF intake through foods in diet in developed countries is very low when compared to developing and underdeveloped countries and therefore emphasis was laid on increasing the intake of TDF in developed countries (National Research Council, 1989). The daily TDF intake from fruits, calculated from data based on the national survey in Japan, was in the range of 0.53–2.50 g% per day per person (Nishimune et al., 1993); this is insignificant compared to total daily TDF intake from diet. Results of the present study will be useful to dietitians and to revise dietary guidelines in recommending fruits rich in SDF to the Indian population. 3.2. Fiber content of fruits in different studies Table 2 gives the fiber content of fruits in different studies. The TDF values for the fruits obtained in the present study were higher than the CF values for the corresponding fruits reported in the Nutritive Value of Indian Foods (Gopalan et al., 2000). This variation could be due to differences in the methodology applied for the determination of fiber content in foods. The TDF values of fruit banana (1.8 g%), cherry (1.5 g%), mango (2.0 g%), peach (1.6 g%) and muskmelon (0.8 g%) obtained in the present study were more or less similar to the DF values reported in ‘‘Food Composition and Nutrition Tables’’. However, for all other fruits, higher TDF values were observed in the present study compared to those reported in ‘‘Food Composition and Nutrition Tables’’ (Souci, Fachmann, & Krant, 2000) except for orange (1.1 g%) which showed a lower value. The TDF values of some of the fruits analyzed in the present study were in general higher than those reported by Chang, Lee, Lin, and Chen (1998), except for banana, papaya and watermelon. It was also observed that there were lower TDF values for apple (3.2 g%), orange (1.1 g%), peach (1.6 g%) and muskmelon (0.8 g%) than the corresponding values reported by Chang et al. (1998). The TDF values of seven fruits (apple, guava, pear, plum, pineapple, strawberry and muskmelon) in the present study were higher than those reported by Holland et al. (1993). It was also observed that there were lower TDF values for mango (2.0 g%), orange (1.1 g%), peach (1.6 g%) and watermelon (0.6 g%) than those reported for the corresponding fruits by Holland et al. (1993). The observed variations in TDF contents of Indian fruits in the
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Table 2 Fiber content of fruits in different studies Fruit
Apple Banana Cherry Guava Mango Orange Papaya Pear Peach Plum Pine apple Strawberry Watermelon Muskmelon
Crude fiber (NVIF) (g/100 g)a
Total dietary fiber (g/100 g) FCNT (2000)b
Chang et al. (1998)
McCance & Widdowson (Southgate)c
Present study
1.0 0.4 0.4 5.2 0.7 0.3 0.8 1.0 1.2 0.4 0.5 1.0 0.2 0.4
2.0 1.8 1.3 5.2 1.7 1.6 1.9 3.3 1.9 1.6 1.0 1.6 0.2 0.7
4.2 2.0 0.7 5.3 1.4 5.4 2.7 3.2 3.9 1.7 1.6 1.7 0.8 1.4
2.0 2.0 1.5 4.7 2.9 1.8 2.3 2.1 2.3 2.3 1.3 2.0 0.9 0.3
3.2 1.8 1.5 8.5 2.0 1.1 2.5 4.3 1.6 2.8 2.8 2.3 0.6 0.8
a
NVIF: Nutritive Value of Indian Foods (Gopalan et al., 2000). FCNT: Food Composition and Nutrition Tables, CRC Press, Germany, 2000. c McCance and Widdowson’s ‘‘The Composition of Foods’’, 1993. b
present study and those reported by earlier studies could be attributed to the differences in genetic make up and agronomic and climatic conditions of cultivation. 3.3. Dietary fiber content of mango varieties Table 3 gives the moisture, TDF, IDF, SDF and SDF as % of TDF, of mango varieties. The moisture content of mango varieties ranged from 74.1 g% in banganapalli to 90.3 g% in peddarasaloo, while in pickle mangoes, it was around 83.9 g%. Among the mango varieties, the TDF and IDF contents were low in panchadarakalasa (1.3 and 0.5 g%) and high in banganapalli (3.0 and 1.5 g%). The SDF was low in dashehari (0.7 g%) and high in eruman (1.6 g%). The SDF as % TDF ranged between 46.7% in dashehari and 61.5% in panchadarakalasa, but most of the mango varieties had around 50% of their TDF as SDF. Gourgue, Champ, Lozano, and DelortLaval (1992) have shown that the mango pulp has IDF and SDF in the ratio of one and made similar observations. Among the two pickle varieties of mango analyzed, the moisture contents were 81.2 and 86.6 g%, respectively. The TDF, IDF and SDF contents were 2.3, 1.0 and 1.3 g% in big pickle mango and 3.8, 1.8 and 2.0 g% in small pickle mango, respectively. SDF as percent of TDF was in the range of 52.6–56.5%. The results of the present investigation on TDF, IDF and SDF contents of commonly consumed Indian fruits indicate that the TDF values are much higher than the CF values of corresponding fruits (Table 1). The CF contents of fruits reported in Nutritive Value of Indian
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Table 3 Moisture, total, insoluble and soluble dietary fiber contents of mango (Mangifera indica) varieties (mean7s.e.) S. No
Fruit
Moisture (g/100 g)
TDF (g/100 g)
IDF (g/100 g)
SDF (g/100 g)
SDF as % of TDF
1 2 3 4 5 6 7 8 9 10 11
Panchadara Kalasa Dashehari Vikarabad Mahamooda Rumani Totapuri Peddarasaloo Neeligova Eruman Banganapalli Pickle mango (big) Pickle mango (small)
83.670.86 80.370.37 84.570.22 82.270.24 86.270.38 90.370.37 85.871.26 81.970.86 74.170.59 86.670.78 81.270.67
1.370.04 1.570.06 1.670.02 1.770.01 2.070.06 2.070.04 2.370.14 2.970.35 3.070.17 2.370.11 3.870.12
0.570.01 0.870.06 0.870.02 0.870.01 1.070.02 0.870.02 1.270.08 1.370.10 1.570.08 1.070.06 1.870.07
0.870.04 0.770.03 0.870.02 0.970.01 1.070.05 1.270.03 1.170.08 1.670.25 1.570.12 1.370.05 2.070.09
61.571.25 46.772.76 50.070.62 52.970.01 50.071.03 60.070.79 47.871.19 55.271.96 50.071.32 56.570.84 52.671.44
TDF: total dietary fiber; IDF: insoluble dietary fiber; SDF: soluble dietary fiber. No. of samples: four determinations in duplicate for each mango variety.
Foods (Gopalan et al., 2000), were estimated by chemical methods, whereas the TDF values in the present study were assessed by enzymatic and gravimetric methods (Prosky et al., 1988). The differences in fiber contents of fruits may be due to the differences in methodology used for the determination of fiber. The unavailable carbohydrate values of banana (2.5 g%) and mango (2.3 g%) estimated by Kamath and Belavady (1980) with the Southgate method were higher than the corresponding TDF values for banana (1.8 g%) and mango (2.0 g%) obtained in the present study by enzymatic and gravimetric methods (Prosky et al., 1988). The discrepancies observed between the results of the present study and those reported by Chang et al. (1998) for the corresponding fruits could be due to varietal or location differences and agro-climatic or soil condition differences. From the results observed in this study, it is evident that fruits such as fig, mango, orange, papaya and sweet lime are rich sources of SDF, the component of TDF associated with a number of health benefits. Among the mango varieties, banganapalli and eruman appear to be better sources of SDF than others. The data generated in the present study on TDF, IDF and SDF contents of different fruits will be useful in selecting appropriate fruits rich in SDF for incorporation into the Indian diets to promote better health. Also they can be included in the food composition tables, which in turn will help dietitians to plan SDF rich diets for diabetic and hyperlipidemic subjects. These data will also be useful to the National Nutrition Monitoring Bureau (NNMB) for computing the DF intake of different population groups in India. In addition they shall also help in computing the correct values for available carbohydrates from these different fruits.
Acknowledgements The authors wish to thank Dr. Kamala Krishnaswamy, Former Director, National Institute of Nutrition (NIN), Indian Council of Medical Research, Hyderabad, India for her valuable
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suggestions, interest and encouragement in carrying out the present study. We wish to thank Dr. B. Sivakumar, Officer-in-Charge, NIN, for his keen interest in this study.
References Al-Habori, M., & Raman, A. (1998). Antidiabetic and hypocholesterolaemic effects of Fenugreek. Phytotherapy Research, 12, 224–233. Chang, S. C., Lee, M. S., Lin, C. J., & Chen, M. L. (1998). Dietary fiber content and composition of fruits in Taiwan. Asia Pacific Journal of Clinical Nutrition, 7, 206–210. FAO (1998). Carbohydrates in human nutrition-FAO/WHO expert consultation on carbohydrates in human nutrition. FAO Food and Nutrition Paper 66. Rome, Italy: FAO. Food and Nutrition Board (2002). Dietary, functional and total fiber. In Institute of Medicine (Eds.), Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids (macronutrients) (pp. 265–334). Washington, DC, USA: National Academy Press. Gillman, M. W., Cupples, L. A., Gagnon, D., Posner, B. M., Ellisor Castelli, W. P., & Wolf, P. A. (1995). Protective effect of fruit and vegetables on development of stroke in men. Journal of the American Medical Association, 273, 1113–1117. Gopalan, C., Ramasastri, B. V., & Balasubramanian, S. C. (2000). Proximate principles: Common foods. In B. S. Narasinga Rao, K. C. Pant, & Y. G. Deosthale (Eds.), Nutritive value of Indian foods (Revised and updated edition) (pp. 53–55). Hyderabad, India: National Institute of Nutrition, ICMR. Gourgue, C. M. P., Champ, M. J. M., Lozano, Y., & Delort-Laval, J. (1992). Dietary fiber from mango by-products: Characterisation and hypoglycaemic effects determined by in vitro methods. Journal of Agricultural and Food Chemistry, 40, 1864–1868. Holland, B., Welch, A. A., Unwin, I. D., Buss, D. H., Paul, A. A., & Southgate, D. A. T. (1993). Fruits. In B. Holland, A. A. Welch, I. Unwin, D. H. Buss, A. A. Paul, & D. A. T. Southgate (Eds.), McCance and Widdowson’s The Composition of Foods (5th revised and extended edition) (pp. 280–311). Cambridge, UK: Royal Society of Chemistry and Ministry of Agriculture, Fisheries and Food. Indian Council of Medical Research (1998). Recommended dietary allowances for Indians. In Expert Committee for Dietary Guidelines (Eds.), Dietary guidelines for Indians—a manual (pp. 65–76). Hyderabad, India: National Institute of Nutrition, ICMR. Jenkins, D. J. A., Kendall, C. W. C., & Ransom, T. P. P. (1998). Dietary fiber, the evolution of the human diet and coronary heart disease. Nutrition Research, 18, 633–652. Johnson, R. K., & Kennedy, E. (2000). The dietary guidelines for Americans; what are the changes and why were they made? Journal of the American Dietetic Association, 100, 769–774. Kamath, M. V., & Belavady, B. (1980). Unavailable carbohydrates of commonly consumed Indian foods. Journal of the Science of Food and Agriculture, 30, 194–220. Lairon, D. (1996). Dietary fibers: Effects on lipid metabolism and mechanisms of action. European Journal of Clinical Nutrition, 50, 125–133. Marlett, J. A. (1992). Content and composition of dietary fiber in 117 frequently consumed foods. Journal of the American Dietetic Association, 92, 175–286. Marlett, J. A., McBurney, M. I., & Slavin, J. L. (2002). Position of the American Dietetic Association: Health implications of dietary fiber. Journal of the American Dietetic Association, 102, 993–1000. Mori, B., Nakaji, S., Sugawara, K., Ohta, M., Iwane, S., Munakata, A., Yoshid, Y., & Ohi, G. (1996). Proposal for recommended level of dietary fiber intake in Japan. Nutrition Research, 16, 53–60. National Research Council (1989). Dietary fiber, in Committee on Diet and Health, Food and Nutrition Board, Commission Life Sciences (Eds.), Diet and health implications for reducing chronic disease risk (pp. 291–309). Washington, DC, USA: National Academy Press. Nishimune, T., Sumimoto, T., Konishi, Y., Yakushiji, T., Komachi, Y., Mitsuhashi, Y., Nakayama, I., Okazaki, K., Tsuda, T., Ichihashi, A., Adachi, T., Imanaka, M., Kirigaya, T., Ushio, H., Kasuga, Y., Saeki, K., Yamamoto, Y.,
ARTICLE IN PRESS P. Ramulu, P. Udayasekhara Rao / Journal of Food Composition and Analysis 16 (2003) 677–685
685
Ichikawa, T., Nakahara, S., & Oda, S. (1993). Dietary fiber intake of Japanese younger generations and the recommended daily allowance. Journal of Nutritional Science and Vitaminology, 39, 263–278. Prosky, L., Asp, N. G., Schweitzer, T. F., DeVries, W. J., & Furda, I. (1988). Determination of insoluble, soluble and total dietary fiber in foods and food products: Interlaboratory study. Journal of the Association of Official Analytical Chemists, 71, 1017–1024. Ramulu, P., & Udayasekhararao, P. (1997). Effect of processing on dietary fiber content of cereals and pulses. Plant Foods for Human Nutrition, 50, 249–257. Roberfroid, M. (1993). Dietary fibre, inulin and oligofructose: A review comparing their physiological effects. CRC Critical Review of Food Science and Nutrition, 33, 103–148. Schweitzer, T.F., & Edwards, C.A. (1992). Dietary fiber, nutritional function, health and disease—a component of food (pp. 295-332), London, UK: Springer. Selvendran, R. R. (1984). The plant cell wall as a source of dietary fiber: Chemistry and structure. American Journal of Clinical Nutrition, 39, 320–337. Selvendran, R. R., & MacDougall, A. J. (1995). Cell-wall chemistry and architecture in relation to sources of dietary fibre. European Journal of Clinical Nutrition, 49(3), S27–S41. Singh, R. B., Niaz, M. A., Ghosh, S., Singh, R., & Rastogi, S. S. (1993). Effect of mortality and reinfarction of adding fruits and vegetables to a prudent diet in the Indian experiment of infarct survival (IEIS). Journal of the American College of Nutrition, 12, 255–261. Souci, S.W., Fachmann, W., & Krant, H. (2000). Fruits. In H. Scherz, & F. Senser (Eds.), Food composition and nutrition tables (6th revised and completed edition) (pp. 873–1071). Stuttgart, Germany: Medpharm Scientific Publication, CRC Press. Southgate, D. A. T. (1969). Determination of carbohydrates in foods. II—unavailable carbohydrates. Journal of the Science of Food and Agriculture, 20, 331–335. Spiller, G. A. (2001). Dietary fiber in prevention and treatment of disease. In G. A. Spiller (Ed.), CRC handbook of dietary fiber in human nutrition (pp. 363–431). Washington: CRC Press LLC. Van Soest, P. J., & Wine, R. H. (1967). Use of detergents in the analysis of fibrous feeds. IV. Determination of plant cell-wall constituents. Journal of the Association of Official Analytical Chemists, 50, 50–55. Visveswara Rao, K. (1996). Variance and standard deviation. In K. Visveswara Rao (Ed.), Biostatistics—a manual of statistical methods for use in health, nutrition and anthropology (pp. 64–68). New Delhi, India: Jaypee Brothers Medical Publishers Pvt. Ltd.
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
Journal of Food Composition and Analysis 16 (2003) 677–685 www.elsevier.com/locate/jfca
Original Article
Total, insoluble and soluble dietary fiber contents of Indian fruits Punna Ramulu*, Paruchuri Udayasekhara Rao Food Chemistry Division, National Institute of Nutrition, Indian Council of Medical Research, Jamai-Osmania (P.O), Hyderabad 500 007, India Received 30 September 2002; received in revised form 21 February 2003; accepted 13 April 2003
Abstract This work provides new data on total (TDF), insoluble (IDF) and soluble (SDF) dietary fiber contents of Indian fruits, which play an important role in human nutrition. Twenty-five common fruits and nine mango varieties were analyzed for their TDF, IDF and SDF contents by enzymatic and gravimetric method of AOAC. Among the fruits, the TDF and IDF contents ranged between 0.6 and 0.3 g% in watermelon and 10.9 and 9.1 g% in sapota, respectively. The SDF content ranged from 0.3 g% in watermelon to 2.4 g% in fig. The SDF as percentage of TDF was low in pear (7.0%) and high in sweet lime (51.8%), but in general, the majority of the fruits had 30%. In mango varieties the TDF and IDF contents were low in panchadarakalasa (1.3 and 0.5 g%) and high in banganapalli (3.0 and 1.5 g%), respectively. The SDF content was low in dashehari (0.7 g%) and high in eruman (1.6 g%). The SDF as % TDF ranged between 46.9% in dashehari and 61.5% in panchadarakalasa, but most of the mango varieties had around 50% of their TDF as SDF. Results indicate that fruits such as fig, mango, orange, papaya and sweet lime are rich sources of SDF, the component of TDF associated with a number of health benefits. The TDF contents of fruits analyzed in the present study were higher than their crude fiber content. r 2003 Elsevier Ltd. All rights reserved. Keywords: Fruits; Mango varieties; Crude fiber; Total dietary fiber; Insoluble dietary fiber; Soluble dietary fiber
1. Introduction Dietary fiber (DF) plays an important role in decreasing the risks of many disorders such as constipation, diabetes, cardiovascular diseases (CVD), diverticulosis and obesity (Spiller, 2001). *Corresponding author. Tel.: +91-40-7008921; fax: +91-40-7019074. E-mail address: p [email protected] (P. Ramulu). 0889-1575/$ - see front matter r 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0889-1575(03)00095-4
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Plant foods are the only sources of DF. All the fractions (cellulose, lignin, hemicellulose, pectins, gums and mucilages) of DF are the major constituents of plant cell wall (Selvendran, 1984; Selvendran & MacDougall, 1995). Dietary fiber is subdivided into Insoluble (IDF) and soluble (SDF) dietary fiber depending on their solubility in water. However, the DF can be grouped into two major types (a) soluble/viscous/fermentable and (b) insoluble/nonviscous/slowly fermentable (Roberfroid, 1993). Recently, FAO/WHO discussion document on carbohydrates recommended dropping the terms ‘‘soluble’’ and ‘‘insoluble’’ fiber (FAO, 1998). The physiological effects of total dietary fiber (TDF), in the forms of insoluble and soluble fractions of foods, have a significant role in human nutrition (Schweitzer & Edwards, 1992). Indian diets predominantly consist of a variety of plant foods such as cereals, pulses, green leafy vegetables (GLV), roots, tubers, other vegetables, fruits, oil seeds, spices and condiments. Fruits are consumed in various forms like fresh, dried, frozen or canned (Marlett, 1992). The polysaccharides comprising a major part of DF in fruits and vegetables are beneficial to healthy human volunteers, since the consumption of fiber lowers plasma cholesterol levels (Jenkins, Kendall, & Ransom, 1998). Gillman et al. (1995) reported protective effect of fruits and vegetables against the development of stroke in men. Addition of fruits and vegetables to the regular diet of infarcted survivors resulted in a decreased mortality and subsequent infarctions (Singh, Niaz, Ghosh, Singh, & Rastogi, 1993). Therefore, the dietary fiber may play a major role in determining the health and disease conditions of different population groups. The data on DF content and its components in fruits are not available in India. The dietary reference value (DRV) for the DF has not been prescribed so far, either in India (Indian Council of Medical Research, 1998), or in most other countries. Some organizations suggested 10 g DF/1000 kcal as an interim recommendation (Mori et al., 1996) and Food and Nutrition Board (2002), Institute of Medicine, USA recommended approximately 14 g TF/ 1000 Kcal. No systematic studies are available so far in this regard. Presently, the food composition tables give crude fiber (CF) content but not DF content of foods in India (Gopalan, Ramasastri, & Balasubramanian, 2000). Moreover, the methodology for the determination of fiber content of foods has changed from time to time from a chemical method (Van Soest & Wine, 1967) to chemical and gravimetric method (Southgate, 1969) to an enzymatic and gravimetric method (Prosky, Asp, Schweitzer, DeVries, & Furda, 1988). The methodology for the enzymatic and gravimetric determination of DF content of foods simulates the human physiological digestive process and hence gives more accurate/ relevant values. Therefore, it is necessary to adopt a suitable method for the determination of TDF, IDF and SDF contents of foods, which mimics the human physiological conditions. Our earlier studies at National Institute of Nutrition for determining the TDF, IDF and SDF content of cereals and pulses demonstrated that most of the cereals are a rich source of IDF, except wheat, which is rich in both IDF and SDF. Pulses are good sources of IDF as well as SDF (Ramulu & Udayasekhararao, 1997). Since a variety of health benefits have been attributed to the consumption of fruits and as there are no data available on TDF, IDF and SDF contents of most of the commonly consumed fruits in India, the present study has been undertaken.
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2. Materials and methods 2.1. Collection of samples Twenty-five different types of fruits (amla, apple, banana, cherry, custard apple, fresh dates, fig, grape, guava, jackfruit, jambu, mango, muskmelon, orange, papaya, peach, pear, pineapple, plum, pomegranate, sapota, strawberry, sweet lime, watermelon and zizyphus) were purchased from local markets. Each variety of fruit was collected from four different places to assess the variation in their TDF, IDF and SDF contents. Nine authentic mango varieties (banganapalli, dashehari, eruman, neeligova, panchadarakalasa, peddarasaloo, rumani, totapuri, and vikarabad mahamooda) were obtained from Acharya N.G. Ranga Agricultural University, Rajendranagar, Hyderabad, India. Two pickle mango varieties (small and big) were also collected from markets. 2.1.1. Samples preparation Fresh fruits were cleaned with water and external moisture wiped out with a dry cloth. The edible portion of the individual fruits was separated, weighed and homogenized thoroughly in a mixer and a known weight of the sample was quantitatively transferred into 500 ml round bottom flasks (glass) and lyophilized. Freeze-dried sample was extracted with diethyl ether to remove the fat content. The total soluble free sugars present in the sample were extracted with 80% hot ethanol. The sample was rinsed with acetone to remove any traces of moisture from the sample and finally, dried in a hot air oven at 50 C for 1 h. The dried samples were then powdered in cyclotech mill using 100-mesh size to get a fine powder. 2.2. Determination of TDF, IDF and SDF Moisture and fat free samples were analyzed for their TDF, IDF and SDF contents by enzymatic and gravimetric method of the Association of Official Analytical Chemists (AOAC) (Prosky et al., 1988), using TDF-100 kit obtained from Sigma chemical company, USA. Along with the test samples, blank and reference samples were also analyzed simultaneously in duplicate for comparison. TDF, IDF and SDF contents of the various fruits analyzed were calculated and expressed on fresh weight basis. 2.2.1. Data analyses The data generated on TDF, IDF and SDF contents of the commonly consumed fruits have been evaluated by parametric tests for statistical significance (Visveswara Rao, 1996).
3. Results and discussion 3.1. TDF, IDF and SDF contents of fruits Table 1 gives the moisture, CF, TDF, IDF, SDF and SDF expressed as % of TDF, contents of common Indian fruits. Among the fruits, the moisture content was low in dates (fresh) (18.8 g%),
680
Fruit common name (Botanical name)
Moisture (g/100 g)
CF (g/100 g)a
TDF (g/100 g)
IDF (g/100 g)
SDF (g/100 g)
SDF as % TDF
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Watermelon (Citrullus vulgaris) Muskmelon (Cucumis melo) Orange (Citrus aurantium) Grapes (Vitis vinifera) Cherry (Prunus cerasus) Peach (Amygdalis persica) Banana (Musa paradisiaca) Mango (Mangifera indica) Strawberry (Fragaria vesca) Papaya (Carica papaya) Sweet lime (Citrus sinensis) Pomegranate (Punica granatum) Pineapple (Ananas comosus) Plum (Prunus domestica) Apple (Malus sylvestris) Jackfruit (Artocarpus heterophyllus) Jambu (Syzygium cumini) Zizyphus (Zizyphus jujuba) Pear (Prunus persica) Fig (Ficus carica) Custard apple (Anona squamosa) Amla (Emblica officinalis) Dates (fresh) (Phoenix dactylifera) Guava (Psidium guajava) Sapota (Achras sapota)
96.470.08 94.670.24 88.470.37 85.170.74 92.270.70 88.270.84 81.171.54 79.973.76 92.970.74 77.873.53 91.170.29 81.370.48 86.070.60 85.77.0.44 86.470.41 74.070.47 77.170.55 84.071.63 85.471.03 75.470.88 76.772.54 80.970.29 18.871.37 81.271.03 74.470.68
0.2 0.4 0.3 0.9 0.4 1.2 0.4 0.7 1.1 0.8 0.5 2.1 0.5 0.4 1.0 1.1 0.9 — 1.0 2.2 3.1 3.4 3.7 5.2 2.6
0.670.02 0.870.01 1.170.03 1.270.06 1.570.03 1.670.04 1.870.12 2.070.19 2.370.11 2.670.08 2.770.06 2.870.11 2.870.13 2.870.07 3.270.21 3.570.08 3.570.02 3.870.37 4.370.25 5.070.21 5.570.20 7.370.10 7.770.46 8.570.44 10.970.44
0.370.01 0.570.01 0.670.03 0.870.04 0.970.03 1.170.02 1.170.06 1.070.10 1.670.08 1.370.05 1.370.03 2.370.07 2.370.12 1.770.05 2.370.19 2.170.13 2.670.04 2.870.22 4.070.23 2.670.09 4.070.15 5.870.10 6.970.46 7.170.40 9.170.38
0.370.01 0.370.01 0.570.03 0.470.02 0.670.03 0.570.03 0.770.06 1.070.10 0.770.04 1.370.04 1.470.06 0.570.06 0.570.03 1.170.03 0.970.05 1.470.05 0.970.02 1.070.17 0.370.03 2.470.17 1.570.08 1.570.06 0.870.06 1.470.01 1.870.11
50.070.86 37.570.77 45.570.97 33.370.44 40.071.76 31.371.76 38.971.20 50.071.81 30.470.99 50.070.86 51.871.47 17.871.60 17.870.74 39.370.29 28.171.48 40.072.35 25.770.74 26.372.21 7.070.49 48.071.68 27.370.10 20.570.85 10.471.07 16.570.60 16.571.26
TDF: total dietary fiber; IDF: insoluble dietary fiber; SDF: soluble dietary fiber. No. of samples: four in duplicate determinations for each fruit. a CF: crude fiber values are taken from ‘‘Nutritive Value of Indian Foods’’ (Gopalan et al., 2000).
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Table 1 Moisture, crude fiber, total, insoluble and soluble dietary fiber contents of fruits (mean7s.e.)
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and high in watermelon (96.4 g%). The TDF and IDF contents of the fruits ranged between 0.6 and 0.3 g% in watermelon and 10.9 and 9.1 g% in sapota, respectively. The SDF content ranged from 0.3 g% in watermelon to 2.4 g% in fig. The SDF as % of TDF was low in pear (7.0%) and high in sweet lime (51.8%). Interestingly, the majority of the fruits had 30% of TDF as SDF. The SDF expressed as % of TDF was around 50% in fig, mango, orange, papaya, sweet lime and watermelon indicating that these fruits are rich in SDF. Foods high in SDF content, such as fenugreek (Al-Habori & Raman, 1998), guar gum, oat and psyllium are known for their hypoglycemic and hypocholesterolemic effects in experimental animals as well as in humans (Lairon, 1996). Though fruit consumption in India is meager in quantitative terms, it is a good source of SDF. Thus, the inclusion of fruits rich in SDF content in the regular diet may be beneficial. Both American Dietetic Association (ADA) and Dietary Guidelines for Americans recommended the inclusion of a variety of grains, vegetables and fruits for an active and healthy life (Johnson & Kennedy, 2000). A position statement announced recently by the ADA mentions that the public should consume adequate amounts of dietary fiber from a variety of plant foods (Marlett, McBurney, & Slavin, 2002). The source of daily TDF intake through foods in diet in developed countries is very low when compared to developing and underdeveloped countries and therefore emphasis was laid on increasing the intake of TDF in developed countries (National Research Council, 1989). The daily TDF intake from fruits, calculated from data based on the national survey in Japan, was in the range of 0.53–2.50 g% per day per person (Nishimune et al., 1993); this is insignificant compared to total daily TDF intake from diet. Results of the present study will be useful to dietitians and to revise dietary guidelines in recommending fruits rich in SDF to the Indian population. 3.2. Fiber content of fruits in different studies Table 2 gives the fiber content of fruits in different studies. The TDF values for the fruits obtained in the present study were higher than the CF values for the corresponding fruits reported in the Nutritive Value of Indian Foods (Gopalan et al., 2000). This variation could be due to differences in the methodology applied for the determination of fiber content in foods. The TDF values of fruit banana (1.8 g%), cherry (1.5 g%), mango (2.0 g%), peach (1.6 g%) and muskmelon (0.8 g%) obtained in the present study were more or less similar to the DF values reported in ‘‘Food Composition and Nutrition Tables’’. However, for all other fruits, higher TDF values were observed in the present study compared to those reported in ‘‘Food Composition and Nutrition Tables’’ (Souci, Fachmann, & Krant, 2000) except for orange (1.1 g%) which showed a lower value. The TDF values of some of the fruits analyzed in the present study were in general higher than those reported by Chang, Lee, Lin, and Chen (1998), except for banana, papaya and watermelon. It was also observed that there were lower TDF values for apple (3.2 g%), orange (1.1 g%), peach (1.6 g%) and muskmelon (0.8 g%) than the corresponding values reported by Chang et al. (1998). The TDF values of seven fruits (apple, guava, pear, plum, pineapple, strawberry and muskmelon) in the present study were higher than those reported by Holland et al. (1993). It was also observed that there were lower TDF values for mango (2.0 g%), orange (1.1 g%), peach (1.6 g%) and watermelon (0.6 g%) than those reported for the corresponding fruits by Holland et al. (1993). The observed variations in TDF contents of Indian fruits in the
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Table 2 Fiber content of fruits in different studies Fruit
Apple Banana Cherry Guava Mango Orange Papaya Pear Peach Plum Pine apple Strawberry Watermelon Muskmelon
Crude fiber (NVIF) (g/100 g)a
Total dietary fiber (g/100 g) FCNT (2000)b
Chang et al. (1998)
McCance & Widdowson (Southgate)c
Present study
1.0 0.4 0.4 5.2 0.7 0.3 0.8 1.0 1.2 0.4 0.5 1.0 0.2 0.4
2.0 1.8 1.3 5.2 1.7 1.6 1.9 3.3 1.9 1.6 1.0 1.6 0.2 0.7
4.2 2.0 0.7 5.3 1.4 5.4 2.7 3.2 3.9 1.7 1.6 1.7 0.8 1.4
2.0 2.0 1.5 4.7 2.9 1.8 2.3 2.1 2.3 2.3 1.3 2.0 0.9 0.3
3.2 1.8 1.5 8.5 2.0 1.1 2.5 4.3 1.6 2.8 2.8 2.3 0.6 0.8
a
NVIF: Nutritive Value of Indian Foods (Gopalan et al., 2000). FCNT: Food Composition and Nutrition Tables, CRC Press, Germany, 2000. c McCance and Widdowson’s ‘‘The Composition of Foods’’, 1993. b
present study and those reported by earlier studies could be attributed to the differences in genetic make up and agronomic and climatic conditions of cultivation. 3.3. Dietary fiber content of mango varieties Table 3 gives the moisture, TDF, IDF, SDF and SDF as % of TDF, of mango varieties. The moisture content of mango varieties ranged from 74.1 g% in banganapalli to 90.3 g% in peddarasaloo, while in pickle mangoes, it was around 83.9 g%. Among the mango varieties, the TDF and IDF contents were low in panchadarakalasa (1.3 and 0.5 g%) and high in banganapalli (3.0 and 1.5 g%). The SDF was low in dashehari (0.7 g%) and high in eruman (1.6 g%). The SDF as % TDF ranged between 46.7% in dashehari and 61.5% in panchadarakalasa, but most of the mango varieties had around 50% of their TDF as SDF. Gourgue, Champ, Lozano, and DelortLaval (1992) have shown that the mango pulp has IDF and SDF in the ratio of one and made similar observations. Among the two pickle varieties of mango analyzed, the moisture contents were 81.2 and 86.6 g%, respectively. The TDF, IDF and SDF contents were 2.3, 1.0 and 1.3 g% in big pickle mango and 3.8, 1.8 and 2.0 g% in small pickle mango, respectively. SDF as percent of TDF was in the range of 52.6–56.5%. The results of the present investigation on TDF, IDF and SDF contents of commonly consumed Indian fruits indicate that the TDF values are much higher than the CF values of corresponding fruits (Table 1). The CF contents of fruits reported in Nutritive Value of Indian
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Table 3 Moisture, total, insoluble and soluble dietary fiber contents of mango (Mangifera indica) varieties (mean7s.e.) S. No
Fruit
Moisture (g/100 g)
TDF (g/100 g)
IDF (g/100 g)
SDF (g/100 g)
SDF as % of TDF
1 2 3 4 5 6 7 8 9 10 11
Panchadara Kalasa Dashehari Vikarabad Mahamooda Rumani Totapuri Peddarasaloo Neeligova Eruman Banganapalli Pickle mango (big) Pickle mango (small)
83.670.86 80.370.37 84.570.22 82.270.24 86.270.38 90.370.37 85.871.26 81.970.86 74.170.59 86.670.78 81.270.67
1.370.04 1.570.06 1.670.02 1.770.01 2.070.06 2.070.04 2.370.14 2.970.35 3.070.17 2.370.11 3.870.12
0.570.01 0.870.06 0.870.02 0.870.01 1.070.02 0.870.02 1.270.08 1.370.10 1.570.08 1.070.06 1.870.07
0.870.04 0.770.03 0.870.02 0.970.01 1.070.05 1.270.03 1.170.08 1.670.25 1.570.12 1.370.05 2.070.09
61.571.25 46.772.76 50.070.62 52.970.01 50.071.03 60.070.79 47.871.19 55.271.96 50.071.32 56.570.84 52.671.44
TDF: total dietary fiber; IDF: insoluble dietary fiber; SDF: soluble dietary fiber. No. of samples: four determinations in duplicate for each mango variety.
Foods (Gopalan et al., 2000), were estimated by chemical methods, whereas the TDF values in the present study were assessed by enzymatic and gravimetric methods (Prosky et al., 1988). The differences in fiber contents of fruits may be due to the differences in methodology used for the determination of fiber. The unavailable carbohydrate values of banana (2.5 g%) and mango (2.3 g%) estimated by Kamath and Belavady (1980) with the Southgate method were higher than the corresponding TDF values for banana (1.8 g%) and mango (2.0 g%) obtained in the present study by enzymatic and gravimetric methods (Prosky et al., 1988). The discrepancies observed between the results of the present study and those reported by Chang et al. (1998) for the corresponding fruits could be due to varietal or location differences and agro-climatic or soil condition differences. From the results observed in this study, it is evident that fruits such as fig, mango, orange, papaya and sweet lime are rich sources of SDF, the component of TDF associated with a number of health benefits. Among the mango varieties, banganapalli and eruman appear to be better sources of SDF than others. The data generated in the present study on TDF, IDF and SDF contents of different fruits will be useful in selecting appropriate fruits rich in SDF for incorporation into the Indian diets to promote better health. Also they can be included in the food composition tables, which in turn will help dietitians to plan SDF rich diets for diabetic and hyperlipidemic subjects. These data will also be useful to the National Nutrition Monitoring Bureau (NNMB) for computing the DF intake of different population groups in India. In addition they shall also help in computing the correct values for available carbohydrates from these different fruits.
Acknowledgements The authors wish to thank Dr. Kamala Krishnaswamy, Former Director, National Institute of Nutrition (NIN), Indian Council of Medical Research, Hyderabad, India for her valuable
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suggestions, interest and encouragement in carrying out the present study. We wish to thank Dr. B. Sivakumar, Officer-in-Charge, NIN, for his keen interest in this study.
References Al-Habori, M., & Raman, A. (1998). Antidiabetic and hypocholesterolaemic effects of Fenugreek. Phytotherapy Research, 12, 224–233. Chang, S. C., Lee, M. S., Lin, C. J., & Chen, M. L. (1998). Dietary fiber content and composition of fruits in Taiwan. Asia Pacific Journal of Clinical Nutrition, 7, 206–210. FAO (1998). Carbohydrates in human nutrition-FAO/WHO expert consultation on carbohydrates in human nutrition. FAO Food and Nutrition Paper 66. Rome, Italy: FAO. Food and Nutrition Board (2002). Dietary, functional and total fiber. In Institute of Medicine (Eds.), Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids (macronutrients) (pp. 265–334). Washington, DC, USA: National Academy Press. Gillman, M. W., Cupples, L. A., Gagnon, D., Posner, B. M., Ellisor Castelli, W. P., & Wolf, P. A. (1995). Protective effect of fruit and vegetables on development of stroke in men. Journal of the American Medical Association, 273, 1113–1117. Gopalan, C., Ramasastri, B. V., & Balasubramanian, S. C. (2000). Proximate principles: Common foods. In B. S. Narasinga Rao, K. C. Pant, & Y. G. Deosthale (Eds.), Nutritive value of Indian foods (Revised and updated edition) (pp. 53–55). Hyderabad, India: National Institute of Nutrition, ICMR. Gourgue, C. M. P., Champ, M. J. M., Lozano, Y., & Delort-Laval, J. (1992). Dietary fiber from mango by-products: Characterisation and hypoglycaemic effects determined by in vitro methods. Journal of Agricultural and Food Chemistry, 40, 1864–1868. Holland, B., Welch, A. A., Unwin, I. D., Buss, D. H., Paul, A. A., & Southgate, D. A. T. (1993). Fruits. In B. Holland, A. A. Welch, I. Unwin, D. H. Buss, A. A. Paul, & D. A. T. Southgate (Eds.), McCance and Widdowson’s The Composition of Foods (5th revised and extended edition) (pp. 280–311). Cambridge, UK: Royal Society of Chemistry and Ministry of Agriculture, Fisheries and Food. Indian Council of Medical Research (1998). Recommended dietary allowances for Indians. In Expert Committee for Dietary Guidelines (Eds.), Dietary guidelines for Indians—a manual (pp. 65–76). Hyderabad, India: National Institute of Nutrition, ICMR. Jenkins, D. J. A., Kendall, C. W. C., & Ransom, T. P. P. (1998). Dietary fiber, the evolution of the human diet and coronary heart disease. Nutrition Research, 18, 633–652. Johnson, R. K., & Kennedy, E. (2000). The dietary guidelines for Americans; what are the changes and why were they made? Journal of the American Dietetic Association, 100, 769–774. Kamath, M. V., & Belavady, B. (1980). Unavailable carbohydrates of commonly consumed Indian foods. Journal of the Science of Food and Agriculture, 30, 194–220. Lairon, D. (1996). Dietary fibers: Effects on lipid metabolism and mechanisms of action. European Journal of Clinical Nutrition, 50, 125–133. Marlett, J. A. (1992). Content and composition of dietary fiber in 117 frequently consumed foods. Journal of the American Dietetic Association, 92, 175–286. Marlett, J. A., McBurney, M. I., & Slavin, J. L. (2002). Position of the American Dietetic Association: Health implications of dietary fiber. Journal of the American Dietetic Association, 102, 993–1000. Mori, B., Nakaji, S., Sugawara, K., Ohta, M., Iwane, S., Munakata, A., Yoshid, Y., & Ohi, G. (1996). Proposal for recommended level of dietary fiber intake in Japan. Nutrition Research, 16, 53–60. National Research Council (1989). Dietary fiber, in Committee on Diet and Health, Food and Nutrition Board, Commission Life Sciences (Eds.), Diet and health implications for reducing chronic disease risk (pp. 291–309). Washington, DC, USA: National Academy Press. Nishimune, T., Sumimoto, T., Konishi, Y., Yakushiji, T., Komachi, Y., Mitsuhashi, Y., Nakayama, I., Okazaki, K., Tsuda, T., Ichihashi, A., Adachi, T., Imanaka, M., Kirigaya, T., Ushio, H., Kasuga, Y., Saeki, K., Yamamoto, Y.,
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Ichikawa, T., Nakahara, S., & Oda, S. (1993). Dietary fiber intake of Japanese younger generations and the recommended daily allowance. Journal of Nutritional Science and Vitaminology, 39, 263–278. Prosky, L., Asp, N. G., Schweitzer, T. F., DeVries, W. J., & Furda, I. (1988). Determination of insoluble, soluble and total dietary fiber in foods and food products: Interlaboratory study. Journal of the Association of Official Analytical Chemists, 71, 1017–1024. Ramulu, P., & Udayasekhararao, P. (1997). Effect of processing on dietary fiber content of cereals and pulses. Plant Foods for Human Nutrition, 50, 249–257. Roberfroid, M. (1993). Dietary fibre, inulin and oligofructose: A review comparing their physiological effects. CRC Critical Review of Food Science and Nutrition, 33, 103–148. Schweitzer, T.F., & Edwards, C.A. (1992). Dietary fiber, nutritional function, health and disease—a component of food (pp. 295-332), London, UK: Springer. Selvendran, R. R. (1984). The plant cell wall as a source of dietary fiber: Chemistry and structure. American Journal of Clinical Nutrition, 39, 320–337. Selvendran, R. R., & MacDougall, A. J. (1995). Cell-wall chemistry and architecture in relation to sources of dietary fibre. European Journal of Clinical Nutrition, 49(3), S27–S41. Singh, R. B., Niaz, M. A., Ghosh, S., Singh, R., & Rastogi, S. S. (1993). Effect of mortality and reinfarction of adding fruits and vegetables to a prudent diet in the Indian experiment of infarct survival (IEIS). Journal of the American College of Nutrition, 12, 255–261. Souci, S.W., Fachmann, W., & Krant, H. (2000). Fruits. In H. Scherz, & F. Senser (Eds.), Food composition and nutrition tables (6th revised and completed edition) (pp. 873–1071). Stuttgart, Germany: Medpharm Scientific Publication, CRC Press. Southgate, D. A. T. (1969). Determination of carbohydrates in foods. II—unavailable carbohydrates. Journal of the Science of Food and Agriculture, 20, 331–335. Spiller, G. A. (2001). Dietary fiber in prevention and treatment of disease. In G. A. Spiller (Ed.), CRC handbook of dietary fiber in human nutrition (pp. 363–431). Washington: CRC Press LLC. Van Soest, P. J., & Wine, R. H. (1967). Use of detergents in the analysis of fibrous feeds. IV. Determination of plant cell-wall constituents. Journal of the Association of Official Analytical Chemists, 50, 50–55. Visveswara Rao, K. (1996). Variance and standard deviation. In K. Visveswara Rao (Ed.), Biostatistics—a manual of statistical methods for use in health, nutrition and anthropology (pp. 64–68). New Delhi, India: Jaypee Brothers Medical Publishers Pvt. Ltd.