Songklanakarin J. Sci. Technol.31 (6), 605-611, Nov. - Dec. 2009Original ArticleThe effects of banana peel preparations on the properties ofbanana peel dietary fibre concentratePhatcharaporn Wachirasiri1, Siripan Julakarangka2 and Sorada Wanlapa1*1Department of Food Technology,Thailand Institute of Scientific and Technological Research, Khlong Luang, Pathum Thani, 12120 Thailand.2Department of Home Economics, Faculty of Agriculture,Kasetsart University, Phaholyothin, Chatuchak, Bangkok, 10900 Thailand.Received 11 July 2008; Accepted 10 November 2008AbstractFour different preparation methods of banana peel, dry milling, wet milling, wet milling and tap water washing, andwet milling and hot water washing were investigated on their effects on the chemical composition and properties of thebanana peel dietary fibre concentrate (BDFC). The dry milling process gave the BDFC a significant higher fat, protein, andstarch content than the wet milling process, resulting in a lower water holding capacity (WHC) and oil holding capacity(OHC). Washing after wet milling could enhance the concentration of total dietary fibre by improving the removal of proteinand fat. Washing with hot water after wet milling process caused a higher loss of soluble fibre fraction, resulting in a lowerWHC and OHC of the obtained BDFC when compared to washing with tap water. Wet milling and tap water washing gavethe BDFC the highest concentration of total and soluble dietary fibre, WHC and OHC.Keywords: banana peel, dietary fibre, wet milling, dry milling, functional properties1. IntroductionBanana is one of the most common crops grown inalmost all tropical countries, including Thailand. Bananaplantations occupy approximately 106,947 ha (data from theOffice of Agricultural Economics, Ministry of Agriculture,Thailand for the 2002 growing season); therefore it is anabundant and cheap agricultural product. Banana chipand banana fig are the main products from banana fleshproduced by a number of small and medium factories locatednationwide. As industrial by-products, peels represent about30-40 g/ 100 g of fruit weight. This resulted in 200 tons ofwaste from banana peels in Thailand generated each day andthis amount tend to increase annually (Pangnakorn, 2006).*Corresponding author.Email address: [email protected] banana peels waste is normally disposed in municipallandfills, which contribute to the existing environmentalproblems. However, the problem can be recovered by utilizing its high-added value compounds, including the dietaryfibre fraction that has a great potential in the preparation offunctional foods.Dietary fibre has shown beneficial effects in the prevention of several diseases, such as cardiovascular diseases,diverticulosis, constipation, irritable colon, colon cancer,and diabetes (Rodriguez et al., 2006). The fruit fibre has abetter quality than other fibre sources due to its high total andsoluble fibre content, water and oil holding capacities, andcolonic fermentability, as well as a lower phytic acid andcaloric value content (Figuerola et al., 2005). A high dietaryfibre content of banana peel (about 50 g/ 100 g) is indicativeof a good source of dietary fibre (Happi Emaga et al., 2007).Happi Emaga et al. (2008) found that the maturation ofbanana fruits has shown to impact the dietary fibre composi-

606P. Wachirasiri et al. / Songklanakarin J. Sci. Technol. 31 (6), 605-611, 2009tions of banana peels. Cellulose, lignin, and hemicellulosecontents of banana peels, the components of the insolubledietary fibre fractions, varied from 7 to 12 g/100 g, 6.4 to9.6 g/100 g and 6.4 to 8.4 g/100 g, respectively, whereaspectin contents, a component of the soluble dietary fibreranged from 13.0 to 21.7 g/100 g. The concentrations ofhydrogen cyanide, an extremely poisonous substance, andoxalate contents in banana peels were found to be 1.33 mg/gand 0.51 mg/g, respectively, falling within the safety limits(Anhwange, 2008). These results indicated that banana peelswere safe and valuable functional ingredients for humanconsumption.Several technological treatments applied to the fruitresidue may affect dietary fibre compositions and functionalproperties (Lario et al., 2004). Larrauri (1999) observed infibre powders obtained from mango and orange peels thatdietary fibre contents and water holding capacity affected bythe time and temperature of washing of the peels. At present,there are no published studies on the suitable processes toproduce dietary fibre from banana peel. Therefore, the overall objective of this study was to investigate the influence ofdifferent preparation methods of banana peels on the chemical compositions and properties of dietary fibre concentrateused as a raw material for functional foods.2. Materials and Methods2.1 MaterialsBananas (Musa ABB) at the color index of 1 (maturegreen) according to the CSIRO banana ripening guide(CSIRO, 1972) were purchased from the local market. Thepeels were removed from the flesh with a stainless steelknife. The commercial -amylase Termamyl 300L Type LS,amyloglucosidase (AMG E) and neutral protease from B.subtilis (Neutrase ) were purchased from Novozyme(Krogshoejvej 36, 2880 Bagsverd, Denmark).2.2 Preparation of banana peel powdersBanana peel powder was prepared utilizing fourmethods: dry milling (DM), wet milling (WM), wet millingand tap water washing (WM-TW), and wet milling and hotwater washing (WM-HW). For the dry milling method,banana peels were dried at 50 C in a hot-air oven overnight,ground by using Udy cyclone mill (Udy cooperation, Colorado USA) and passed a 1 mm screen. The banana peels towater ratio of 1: 5 were blended in a commercial blenderand screened through a 1 mm sieve in a wet milling process(WM). After wet milling, the banana peels prepared by WMTW and WM-HW were washed with tap water and hot waterat 95 C in the same amount as used in the WM process for5 min, respectively. The peel samples were dried at 50 C ina hot air oven for 12 hrs and ground to obtain the bananapeel powder with a particle size of less than 1.0 mm.2.3 Extraction of dietary fibreDietary fibre from banana peel was extracted usingthe method of Yoshimoto et al. (2005). The banana peelpowder samples were defatted for 12 hrs using hexane as asolvent (5 ml/g sample). The residue was dried at 50 C in ahot air oven to assure complete removal of the solvent. Thedefatted peel powder was mixed with water (1: 20 w/v ratio).The pH was adjusted to 5.8 by adding 1 N HCl solution. Analpha-amylase was added (0.1 ml/ g sample). The samplewas incubated at 95 C for 30 min. after cooling down to60 C, the pH was adjusted to 7.5 by adding 1 N NaOH.Neutrase was then added (10 mg/ g sample) and incubatedfor 30 min at 60 C. After that, the pH was adjusted to 4-4.5by using 1 N HCl solution. An amyloglucosidase solutionwas added (0.1 mg/ g sample) at 60 C for 30 min. Finally,the mixture was filtered through Whatman No.4 filter paperand dried in the hot air oven at 50 C for 12 hrs. The driedsamples were then powdered in an Udy cyclone mill (Udycooperation, Colorado USA) using a 1 mm sieve.2.4 Chemical analysisMoisture content was determined by using a moisturemeter at 105 C. Ash, protein, and lipid content were analyzedaccording to AACC methods 08-01, 46-13 and 30-25, respectively (AACC, 2000). Total dietary fibre (TDF), insolubledietary fibre (IDF), and soluble dietary fibre (SDF) contentswere determined by enzymatic and gravimetric method ofAOAC (Prosky et al., 1988), using a TDF-100 kit obtainedfrom Sigma chemical company, U.S.A.Water activity was measured by a water activity meterat 25 C (AquaLab Series 3-Decagon).Color measurements of the banana peel dietary fibrewere carried out instrumentally using a color meter (Chroma,CR200, Japan). The CIE chromaticity coordinates (L*, a*and b*) were measured. The L* values gives a measure ofthe lightness of the product color from 100 for perfect whiteto zero for black. The redness/ greenness and yellowness/blueness are denoted by the a* and b* values, respectively.To evaluate the water holding capacity (WHC) andoil holding capacity (OHC). of the dietary fibres, the amountof water and oil released after centrifugation was quantifiedaccording to the modification of centrifugation method ofLarrauri et al. (1996). The dietary fibre samples of 0.5 gwere stirred in 10 ml of water or soybean oil and left at 30 Cfor 20 min. After that, the mixture was centrifuged at 3,000 g for 20 min and the residue was weighed and WHC andOHC calculated as g water or oil per g of dry sample, respectively.2.5 Statistical analysisBanana peel dietary fibre concentrate preparationand all analyses were performed in triplicate. Data were

607P. Wachirasiri et al. / Songklanakarin J. Sci. Technol. 31 (6), 605-611, 2009Table 1. Proximate composition of banana peel used forpreparation of dietary fibre.ItemsContent (g/100 g dry matter)ProteinFatStarchAshTotal dietary fibre8.6 0.113.1 0.212.78 0.915.25 0.150.25 0.2tion methods was performed in this study in order to enhancethe content of the dietary fibre and lower the content of fat,starch, and protein to obtain the low caloric value products.Moreover, fat and protein trapped inside the fiber matrixhave the evidence to retard the water hydration properties ofdietary fibres (Raghvendra et al., 2004; Yamazaki et al.,2005).3.2 Yieldsubjected to analysis of variance (ANOVA) test followed byDuncan multiple range test to compare means at the 5% significance level.3. Results and Discussion3.1 Chemical compositionThe main components of banana peel used for preparation of dietary fibre were listed in Table 1.The dry matter of banana peel sample was 11 g/100 gsample, which was similar to the values reported by HappiEmaga et al. (2007) (9.5 g/100 g sample). The banana peelhad higher fat, ash, and total dietary fibre content, but lowerprotein and starch content than those of the banana peels atstage 1 of ripeness reported by Happi Emaga et al. (2007)(4.2, 12.8, 37.3, 3.6 and 9.5 g/ 100 g dry matter, respectively). This might be due to the differences in varieties anddue to geographical factors. In comparison with the peels ofother fruits, the protein and fat content of the banana peelwere greater than those of lemon peel (7 and 2.5 g/ 100 g drymatter, respectively) and sweet orange peel (9.1 and 2.6 g/100 g dry matter, respectively). On the other hand, it hadlower total dietary fibre content than fibre obtained fromdifferent sources of fruit industrial by-products (60-78 g/100 g dry matter) as reported by Figuerola et al. (2005),Llobera and Canellas (2007), Marin et al. (2007). Thereforethe removal of the fraction of fat, protein, and starch fromthe banana peel powders prepared by the different prepara-Yields after the removal of protein, starch, and fat frombanana peel powder prepared by the different banana peelpreparation methods were shown in Table 2. The bananapeel dietary fibre concentrates (BDFC) prepared by DM hadsignificantly higher yield than those prepared by the othermethods (P 0.05). In this method, no water washing wasperformed, therefore, there was no loss of undesired components associated to dietary fibre, such as sugar washing outwith water. This result was in accordance with the results ofthe orange peel dietary fibre preparation reported by Larrauri(1999). Hot water washing caused significantly higher lossthan tap water washing (P 0.05) due to the additional lossin the low molecular weight carbohydrate from the thermaldegradation, the leaching to the processed water, and thesolubilization of insoluble dietary fibre components (Nymanet al., 1987).3.2 Chemical compositionChemical compositions of BDFCs prepared by different methods are shown in Table 2. Protein contents of thebanana peel dietary fibres were in the range of 2.09-3.04 g/100 g dry matter, indicating that 55-76 g/100 g of the proteincontent in banana peel was removed by neutral proteaseextraction. The methods of preparation significantly affectedthe protein content left in the BDFCs (P 0.05). The proteincontent of BDFC prepared by wet milling tended to behigher than that prepared by dry milling, although no significant difference was observed. The protein contents in theBDFCs prepared by WM-TW and WM-HW were signific-Table 2. Chemical compositions of the banana dietary fibre concentrates prepared by different methods.Preparation Yield (g/100 gdry weight ofMethodsbanana peel)DMWMWM-TWWM-HW44.041.937.335.6Chemical composition (g/100 g dry matter of dietary fibre)ProteinFatStarchTDFSDFIDFIDF/SDF3.86 0.03b3.44 0.04b2.09 0.04a2.04 0.04a1.43 0.01c0.73 0.18b0.66 0.01b0.74 0.07b4.62 0.01c4.08 0.02b4.08 0.02b2.71 0.01a83.00 0.28a87.77 0.35b89.21 0.85c89.35 0.62c12.84 0.13a17.10 0.30c17.84 0.13c16.29 0.00b70.16 0.27a70.67 0.37a71.37 0.63ab73.06 0.62b5.46:14.13:14.00:14.48:1Values are means standard deviations of three replicate measurements. Treatments followed by same letter (a, b,, ) ina column were not significant different (P 0.05).DM Dry milling, WM Wet milling, DM-TW Wet milling and tap water washing, and WM-HW Wet milling and hotwater washing.

608P. Wachirasiri et al. / Songklanakarin J. Sci. Technol. 31 (6), 605-611, 2009antly lower than those prepared by DM and WM (P 0.05).The wet milling process was known to effectively separateprotein-containing and non-protein-containing products bysoftening the plant tissue for milling, helping breakdown theprotein, and also removing certain soluble constituents(Adejuyitan et al., 2008). The washing process allows for thesoluble proteins to be removed from fibres, especially hotwater washing, which additionally solubilized more proteinsto water by denaturing and made more susceptible toenzyme.Fat contents of the banana peel dietary fibre concentrates ranged between 0.66 and 1.43 g/100 g dry matter; werelower than fat contents in dietary fibre concentrates derivedfrom grape fruit (3.24 g/g dry matter), lemon (1.89 g/100 gdry matter), and apple (2.44 g/100 g dry matter) found byFiguerola et al. (2005) and Llobera and Canellas (2007).The methods of banana peel preparation had significantinfluence on fat content in the BDFCs. Dietary fibre preparedfrom dry milling process had significantly higher fat contentthan those prepared from wet milling processes (P 0.05).It might be due to the removal of some types of fats duringwater treatment. Christie (2003) pointed out that mostcomplex lipids are slightly soluble in water and at least formmicellar solutions, and lipids such as polyphosphoinositides,lysophospholipids, acyl-carnitines, and coenzyme A estersare especially soluble in water.Starch contents in the BDFCs were in the range of2.71 g/100 g dry matter and 4.62 g/100 g dry matter, indicating that 64-78 g/100 g of starch in the banana peel wasremoved by amylase enzyme. The BDFC prepared by drymilling process had significantly higher starch content leftin the product than those prepared by wet milling processes(P 0.05). In wet milling, the plant fibres were hydrated,resulting in a differential swelling and making the starchseparation more effective (Cabrales et al., 2006). The washing by hot water could produce the BDFCs with significantlylower starch content than the others (P 0.05). It might bedue to the fact that hot water washing caused the starch togelatinize, involving the dissolution of hydrogen bondsamong and within starch molecules to open the molecules upto hydration and enzymatic hydrolysis (Hall, 2003).Table 2 shows the total dietary fibre (TDF), insolubledietary fibre (IDF), soluble dietary fibre (SDF) contents ofthe BDFCs, and ratio between IDF and SDF. The BDFCshad more than 80 g/100 g dry matter of TDF. According toFemenia et al. (1997) and Larrauri (1999), these productscould be considered as a rich source of dietary fibre. TheBDFCs had higher TDF content than found in the dietaryfibre concentrate from processing by-products of fruits andgreens (35.8-38.8 g/ 100g dry matter) reported by GrigelmoMiguel and Martin-Belloso (1999b), and in the lemon peeldietary fibre (66-70.4 g/100 g dry matter) reported byUbando-Rivera et al. (2005).IDF was the predominant fraction in all samples. Theinsoluble dietary fiber ranged between 70.16-73.06 g/100 gdry matter. IDF in banana peel fibre as reported by Aregheore(2005) includes hemicellulose (10.1 g/100 g), cellulose (25.6g/100 g), and lignin (12.3 g/100 g). This class of dietary fiberis insoluble in water. It is possible that the BDFCs havepronounced effects on intestinal regulation and stool volume,which are related to the consumption of IDF (GrigelmoMiguel et al., 1999a). The BDFCs prepared by wet millingprocess and subjected to hot water washing had the highestIDF content, followed by the BDFC prepared by WM-TW,DM, and WM. This may be explained by a concentrationeffect. The SDF fraction in the banana fibres ranged between12.84-17.84 g/100 g dry matter, which was greater than thepreviously described values for dietary fibre from residuesfrom juice extraction of grape fruit (4-6 g/100 g dry matter),lemon (6-9 g/100 g dry matter), orange (10 g/100 g drymatter) reported by Figuerola et al. (2005), and DF concentrates from processing by-products of apple (13.8 g/100 gdry matter), pear (14.1 g/100 g dry matter), orange (13.6 g/100 g dry matter), peach (9.71 g/100g dry matter), artichoke(10.4 g/100 g dry matter), and asparagus (10 g/100 g drymatter) reported by Grigelmo-Miguel and Martin-Belloso(1999b). Soluble dietary fiber in banana peels includespectin (Madhav and Pushpalatha (2002), Happi Emaga et al.,2008), fructans (Rodriguez et al., 2006), oligosaccharidesand arabinoxylan (Zhang et al., 2004). This type of dietaryfiber is soluble in water. The result suggests that the BDFCscould possibly be used as a good source of soluble DF inmany food applications. The BDFC prepared by dry millingprocess showed the lowest SDF due to a higher content ofimpurities such as fat, starch, and protein, which are higherthan other samples subjected to wet milling and water washing. No significant difference was found between the BDFCsprepared from WM and WM-TW, which had DF with higherSDF than those subjected to wet milling and hot water washing. It is due to the fact that hot water treatment caused thesolubization of polysaccharides, resulting in the loss of thedietary fibre components, especially in the low molecularweight carbohydrates (Larrauri, 1999; Tatjana et al., 2002).There were found different IDF/ SDF ratios in thesamples studied ranging between 4:1 in BDFCs obtainedusing wet milling and tap water washing and 5.46:1 in BDFCobtained using dry milling process. These values are lowerthan those in lemon (9.9:1) and apple (12.9:1) but are comparable to the values of grape fruit (5.9:1) and orange (5.3:1)reported by Figuerola et al. (2005). The ratio values fromthe banana peel DF are close to the well-balanced valuesaccording to the recommendation of Spiller (1986) (1.0-2.3:1) in order to obtain the physiological effect associated withboth the soluble and insoluble fractions. No significanteffect of the preparation methods on the IDF/SDF ratio wasobserved.3.4 Water holding capacity (WHC) and oil holding capacity (OHC)WHC and OHC are important properties of DF fromboth a physiological and technological point of views. The

609P. Wachirasiri et al. / Songklanakarin J. Sci. Technol. 31 (6), 605-611, 2009BDFCs had high WHC (9.25-10.52 g water/g dry matter)except the sample prepared from dry milling process (Table3). This is in accordance with the results reported by Larioet al. (2004). The lower values of WHC found in the BDFCprepared by DM in comparison with the other methods ofpreparation could be attributed to the lower content ofsoluble DF comprising some components in the plant tissuematerials having the ability to hold water such as pectin,fructan, and arabinoxylan (Stephen and Cummings, 1979;Marin et al., 2007) and the higher content of protein and fatretarding hydration capacity of dietary fibers (Raghvendraet al., 2004; Yamazaki et al., 2005). Moreover, dry millingaffected its physical structure by breaking pores and therefore, the increasing fiber density and so reducing WHC(Cadden, 1987). The WHC values of the BDFCs in this studypresented a great value in comparison with peach dietaryfibre concentrate (9.2-9.3 g water/g fibre) reported byGrigelmo-Miguel et al. (1999). The high WHC of the BDFCsindicates the potentiality to be used as a functional ingredientto avoid syneresis and to modify the viscosity and texture offormulated products (Grigelmo-Miguel et al., 1999).OHC is another functional property of some ingredients used in formulated food (Kuntz, 1994). Ingredients withhigh OHC are useful as emulsifiers for high fat foodproducts. OHC was significantly influenced by the preparation methods (P 0.05) (Table 3). The DM resulted in thelowest OHC, while no significant difference was foundamong the other three methods of preparations. The preparation methods of banana peels may have an influence onthe factors affecting the OHC of dietary fibre, includingsurface properties, overall charge density, thickener, andhydrophobic nature of the fibre particle (Femenia et al.,1997). The values of OHC of the BDFCs were much higherthan those of peach DF (1 g oil/g fibre) reported byGrigelmo-Miguel et al. (1999) and orange fibre DF concentrate (1.2 g oil/g fibre) reported by Grigelmo-Miguel andMartin-Belloso (1999a). The high OHC of the BDFCssuggests their potential use as fibre-rich ingredient in foodstuffs requiring oil retention and cholesterol absorption.3.5 Water activityWater activity (Aw) values of the BDFCs were in therange of 0.43-0.53 (Table 3). These values of Aw of allsamples were lower than the minimum level at which microorganism can grow (about 0.61) (Beauchat, 1981). The wetmilling and washing previous to drying enhanced the Awreduction compared with dry milling. These results are inagreement with those reported by Lario et al. (2004).3.6 ColorAll BDFCs presented brown color, which could bedefined as yellow color with low lightness. The WM-HWresulted in the BDFC with lighter colors than the others,whereas WM and WM-TW yielded a darker color than theothers (Table 4). The b* value of the BDFC made by DMprocess was significantly lower than those of the samplesprepared by the other three methods (P 0.05), which agreeswith the reports from Lario et al. (2004). These results mightbe attributed to the fact the wet milling caused the celldamage, resulting in the phenolic substrate available in thefruit coming into contact with the browning enzyme polyphenoloxidase.4. ConclusionsBanana peel is a good source of dietary fibre exhibiting 50 g/100 g dry matter. The different preparation methodhad an influence on the properties of banana peel dietaryfibre concentrate obtained subsequently after removal of fat,protein, and starch fraction. Dry milling process yielded thebanana dietary fibre concentrates with significantly higherfat, protein, and starch residue than wet milling processes (P 0.05), resulting in the lower dietary fibre concentration.Among the wet milling processes, washing with either tap orhot water contributed to the removal of protein fraction,enhancing the total dietary fibre concentration. Although thewet milling and hot water washing process could reduceTable 3. Water Holding Capacity (WHC), Oil Holding Capacity (OHC) and Water activity (Aw)of the banana dietary fibre concentrates prepared by different methods.Preparation methodWHC(g water/g fibre)OHC(g oil/g fibre)AwDMWMWM-TWWM-HW6.57 0.15a9.62 0.03b10.52 0.36c9.25 0.35b4.75 0.01a5.23 0.69b5.77 0.01b5.17 0.03b0.53 0.00d0.46 0.00c0.43 0.00a0.45 0.01bValues are means standard deviations of three replicate measurements. Treatments followedby same letter (a, b,, ) in a column were not significant different (P 0.05). DM Dry milling,WM Wet milling, DM-TW Wet milling and tap water washing, and WM-HW Wet millingand hot water washing.

610P. Wachirasiri et al. / Songklanakarin J. Sci. Technol. 31 (6), 605-611, 2009Table 4. Color of the banana dietary fibre concentrate prepared bydifferent methods.Preparation methodL*a*b*DMWMWM-TWWM-HW41.14 0.21b32.23 2.28a35.50 2.20a45.04 0.47c5.67 0.18a7.94 0.36b7.69 0.36b5.24 0.11a16.44 0.22a18.39 0.74b18.19 0.86b18.45 0.10bValues are means standard deviations of three replicate measurements.Treatments followed by same letter (a, b,, ) in a column were not significant different (P 0.05). DM Dry milling, WM Wet milling, DM-TW Wet milling and tap water washing, and WM-HW Wet milling and hotwater washing.higher starch fraction in the dietary fibre, the higher loss ofsoluble fibre fraction was observed. Wet milling and tapwater washing gave the banana peel dietary fibre concentratehaving the highest WHC and OHC. This results indicatedthat this treatment was the most effective method to providean opportunity to enhance the functionality of dietary fibreconcentrate and hence to use the banana peel dietary fibreconcentrate as a low-caloric functional ingredient for fibreenrichment, although the incorporation of them within thefood system may slightly affect the color of the final product.ReferencesAACC. 2000. Approved methods (10th ed). American Association of Cereal Chemists. St Paul, Minnesota, USA.Adejuyitan, J. A., Adelakun, O. E., Olaniyan, S. A. andPopoola, F. I. 2008. Evaluating the quality characteristics of kunun produced from dry-milled sorghum.African Journal of Biotechnology. 7(13), 2244-2247.Anhwange, B. A. 2008. Chemical composition of Musasapientum (Banana) peels. Journal of Food Technology. 6(6), 263-266.Aregheore, E. M. 2005. Evaluation and utilization of Noni(Morinda citrifolia) juice extract waste in completediets of goats. Livestock Research for Rural Development. 17. Art. #39. m. [September 29, 2008].Beauchat, C. 1981. Microbial stability as affected by wateractivity. Cereal Foods World. 26(7), 345-349.Cabrales, L., Niu, Y. X., Buriak, P. and Eckhoff, S. R. 2006.Effect of Laboratory Batch Steeping pH on StarchYield and Pasting Properties of Selected Corn Hybrids.Cereal Chemistry. 83, 22-24.Cadden, A. M. 1987. Comparative effects of particle sizereduction on physical structure and water bindingproperties of several plant fibres. Journal of Food Science. 52(6), 357-360.Commonwealth Scientific and Industrial Research Organisation (CSIRO). 1972. Banana ripening guide. BananaResearch Advisory Committee, Technical Bulletin 3.Melbourne, Australia: Banana Research AdvisoryCommittee.Cristie, W. W. 1993. Preparation of lipid extracts fromtissues. In Advances in Lipid Methodology, W. W.Cristie, editor. Oily Press, Dundee, Scotland, pp. 195213.Femenia, A., Lefebvre, C., The baudin, Y., Robertson, J. andBougeois, C. 1997. Physical and sensory propertiesof model food supplemented with cauliflower fiber.Journal of Food Science. 62(4), 635-639.Figuerola, F. Hurtado, M. L., Estevez, A. M., Chiffelle, I. andAsenjo, F. 2005. Fibre concentrates from applepomace and citrus peel as potential fibre sources forfood enrichment. Food Chemistry. 9, 395-401.Grigelmo-Miguel, N. and Martin-Belloso, O. M. 1999a.Characterization of dietary fiber from orange juiceextraction. Food Research International. 31(5), 355361.Grigelmo-Miguel, N. and Martin-Belloso, O. M. 1999b. Comparison of dietary fibre from by-products of processing fruits and greens and from cereals. LebensmittelWissenschaft und Technologie. 32, 503-508.Grigelmo-Miguel, N., Gorinstein, S. and Martin-Belloso, O.M. 1999. Characterization of peach dietary fibreconcentrate as a food ingredient. Food Chemistry. 65,175-181.Hall, M. B. 2003. Challenges with nonfiber carbohydratemethods. Journal of Animal Science. 81, 3226-3232.Happi Emaga, T., Andrianaivo, R. H., Wathelet, B., Tchango,J. T. and Paquot, M. 2007. Effects of the stage of maturation and varieties on the chemical composition ofbanana and plantain peels. Food Chemistry. 103, 590600.Kuntz, L. A. 1994. Fiber: from frustration to functionality.Food Product Design. 2, 91-108.Lario, Y., Sendra, E., Garcia-Perez, J., Fuentes, C., SayasBarbera, E., Fernandez-Lopez, J. and Perez-Alvarez,J. A. 2004. Preparation of high dietary powder fromlemon juice by-products. Innovative Food Science andEmerging Technologies. 5, 113-117.

P. Wachirasiri et al. / Songklanakarin J. Sci. Technol. 31 (6), 605-611, 2009Larrauri, J. A. 1999. New approaches in the preparation ofhigh dietary fibre powders from fruit by-products.Trends in Food Science and Technology. 10, 3-8.Larrauri, J. A., Ruperez, P., Borroto, B. and Saura-Calixto, F.1996. Mango peels as a new tropical fibre: Preparation and Characterization. Lebensmittel Wissenschaftund Technologie. 29, 729-733.Llobera, A. and Canellas J. 2007. Dietary fibre content andantioxidant activity of Manto Negro red grape (Vitisvinifera): pomance and stem. Food Chemistry. 101,659-666.Marin, F. R., Soler-Rivas, C., Benavente-Garcia, O., Castillo,J. and Perez-Alvarez, J. A. 2007. By-products fromdifferent citrus processes as a source of customizedfunctional fibres. Food Chemistry. 100, 736-741.Madhav, A. and Pushpalatha, P. B. 2002. Characterization ofpectin extracted from different fruit wastes. Journalof Tropical Agriculture. 40. 53-55.Nyman, M., Palsson, K. E. and Asp, N. G. 1987. Effects ofprocessing on dietary fiber in vegetables. LebensmittelWissenschaft und Technologie. 20, 20-29-36.Pangnakorn U. 2006. Valuable added the agricultural wastefor farmers using in organic farming groups inPhitsanulok, Thailand. Proceeding of the prosperityand poverty in a globalized world - challenges foragricultural research, Bonn, Germany, October, 1113, 275-278.Prosky, L., Asp, N. G., Schweitzer, T. F., DeVries, W. J. andFurda, I. 1988. Determination of insoluble, solubleand total dietary fiber in foods and food products:Interlaboratory. Journal of the Association of OfficialAnalytical Chemists. 71, 1017-1024.611Raghavendra, S. N., Rastogi, N. K., Raghava

a hot air oven for 12 hrs and ground to obtain the banana peel powder with a particle size of less than 1.0 mm. 2.3Extraction of dietary fibre Dietary fibre from banana peel was extracted using the method of Yoshimoto et al. (2005). The banana peel powder samples were defatted for 12 hrs using hexane as a solvent (5 ml/g sample).