-1DWQ6FL)RXQGDWLRQ6UL/DQND   DOI: http://dx.doi.org/10.4038/jnsfsr.v47i3.8699 RESEARCH ARTICLE &RPSDULVRQRILQWHUYDULHWDOGLႇHUHQFHVLQFKHPLFDOFRPSRVLWLRQ DQGQXWULWLRQDOSURSHUWLHVRIFRFRQXWWHVWDÀRXU S.S.K. Marasinghe1, J.M. Nazrim Marikkar1*, C. Yalegama2, S. Wimalasiri3, G. Seneviratne1, R. Weerasooriya1 and R. Liyanage1 1DWLRQDO,QVWLWXWHRI)XQGDPHQWDO6WXGLHV+DQWDQD5RDG.DQG\ &RFRQXW5HVHDUFK,QVWLWXWH/XQXZLOD  'HSDUWPHQWRI)RRG6FLHQFHDQG7HFKQRORJ\)DFXOW\RI$JULFXOWXUH8QLYHUVLW\RI3HUDGHQL\D3HUDGHQL\D   Submitted: 28 January 2019; Revised: 13 May 2019; Accepted: 24 May 2019 Abstract: Coconut testa is the brown colour thin outer covering of the coconut endosperm. An attempt was made to convert FRFRQXW WHVWD LQWR ÀRXU IRU EDNHU\ SURGXFWV ,Q WKLV VWXG\ chemical composition and nutritional properties of coconut WHVWD ÀRXU RI IRXU ORFDO FXOWLYDUV QDPHO\ 6DQ 5DPDQ *RQ Thambili, Ran Thambili and Tall × Tall were compared against WKRVH RI D FRPPHUFLDO K\EULG JURZQ LQ 6UL /DQND 3DUWLDOO\ defatted coconut parings of each cultivar were oven-dried and JURXQG LQWR FRFRQXW WHVWD ÀRXU 0RLVWXUH FUXGH IDW DVK DQG FUXGHSURWHLQFRQWHQWVRIFRFRQXWWHVWDÀRXUZHUHGHWHUPLQHG according to AOAC methods. The carbohydrate content was FDOFXODWHGE\WKHGL൵HUHQFH,QWHUYDULHWDOGL൵HUHQFHVRIIDWW\ acids and micro-mineral distributions were also determined. 7KH PDLQ FRQVWLWXHQW RI FRFRQXW WHVWD ÀRXU UHJDUGOHVV RI cultivar was carbohydrate (42.55–59.24 %) followed by protein (23.82–32.22 %) and fat (7.93–23.49 %). Commercial hybrid had the highest carbohydrate content (59.24 %) while the minimum carbohydrate content was recorded for San Raman variety (42.55 %). Highest protein content was observed in Gon Thambili (32.22 %) variety while the least was observed in commercial hybrid (23.82 %). The highest fat content was noted in San Raman variety (23.49 %). Tall × Tall variety contained the least fat content (7.93 %). Maximum ash content was observed in Ran Thambili variety (5.30 %) while the least ash content was for Gon Thambili variety (3.70 %). Highest moisture content was prevalent in San Raman variety (4.27 %) while the least was observed in commercial hybrid (2.27 %). 7KHVHUHVXOWVVXJJHVWHGWKDWFRFRQXWWHVWDÀRXULVDQXWULWLRXV substance, which provides value addition to the under-utilised by-product of coconut processing industry. * Corresponding author (nazrim.ma@nifs.ac.lk; Keywords: &RFRQXW FRFRQXW WHVWD ÀRXU IDWW\ DFLGV PLFUR minerals, proximate composition. INTRODUCTION Coconut (&RFRVQXFLIHUD L.) is a crop grown in more than 85 countries worldwide, with a total production of 54 billion nuts per annum. The island country of Sri Lanka is WKHZRUOG¶V¿IWKODUJHVWSURGXFHURIFRFRQXWV&RFRQXWLV grown mainly in the traditional coconut triangle, although patches of coconut cultivation could also be seen in other parts of the country. The endemic coconut germplasm of Sri Lanka consists mainly of three varieties; typica (tall palm), nana (dwarf palm), and aurantica (king coconut palm). These varieties are generally distinguishable based on their morphological characters as well as the breeding habits (Liyanage, 1958; Fernando, 1999). Despite the PDMRU FKDUDFWHULVWLF GL൵HUHQFHV WKHUH DUH RWKHU PLQRU variations within each variety, which lead them to be FODVVL¿HGIXUWKHULQWRGL൵HUHQWIRUPVRIFRFRQXWNQRZQ as cultivars. As a perennial crop, coconut is one of the most economically important crops in the tropics, serving as a source of food, drink, fuel, medicine, and construction material (Lima et al., 2015). An average mature Sri Lankan type coconut is composed of about 45 % husk, https://orcid.org/0000-0002-0133-5852) This article is published under the Creative Commons CC-BY-ND License (http://creativecommons.org/licenses/by-nd/4.0/). This license permits use, distribution and reproduction, commercial and non-commercial, provided that the original work is properly cited and is not changed in anyway.  66.0DUDVLQJKHHWDO 13 % shell, 22 % meat and 20 % water (Marikkar et al., 2009). The most economically important part of coconut is its endocarp; the hard dark core of the fruit. Inside this part is a solid white endosperm of varied thickness, depending on the maturity of the fruit (Lima et al., 2015). In an earlier report, Nathanael (1966) pointed out that the coconut endosperm had some unique features such that the layer closest to the water cavity was least rich in oil (~56.3%) while the layer nearest to the brown testa was richest in oil (~75.4 %). Later investigations into this aspect showed that the oil characteristics of the EURZQWHVWDZHUHVOLJKWO\GL൵HUHQWIURPWKRVHRIWKHRLO characteristics of inner layers of the kernel (Marikkar & Nasyrah, 2012). of each cultivar were subjected to cold press oil extraction using a micro oil expeller (Komet DD85 machine, *HUPDQ\ 3DUWLDOO\GHIDWWHGFRFRQXWWHVWD OHVVWKDQ RLOFRQWHQW ZHUHJURXQGLQWR¿QHFRFRQXWWHVWDÀRXUXVLQJ a grinder. The entire process was carried out according to WKHVHTXHQFHLOOXVWUDWHGLQ)LJXUH7KHJURXQGHGÀRXU samples were then stored at refrigerated (4 °C) condition for further analysis. All chemicals used in this study were RIDQDO\WLFDOJUDGHXQOHVVRWKHUZLVHVSHFL¿HG 6HDVRQHGQXWV 'HKXVNLQJ Coconut testa is the brown coloured thin outer covering of the coconut endosperm. It is an underutilised by-product of the desiccated coconut industry; it is often XVHGDVDQLPDOIHHG3UHYLRXVLQYHVWLJDWLRQVE\$SSDLDK et al. (2014) showed that it is a rich source of bioactive FRPSRXQGV VXFK DV SKHQROLFV DQG ÀDYDQRLGV ,W KDV potential to be used as a functional ingredient by the food SURFHVVLQJLQGXVWU\$OWKRXJKGHYHORSPHQWRIÀRXURXW of coconut kernel has been the interest of researchers for preparation of snack foods (Yalegama et al., 2013), the VWXGLHVRQXWLOLVDWLRQRIFRFRQXWWHVWDDVDVRXUFHRIÀRXU is scanty. Hence, the aim of this study was to evaluate LQWHUFXOWLYDU GL൵HUHQFHV LQ SUR[LPDWH FRPSRVLWLRQ mineral content and fatty acid distribution of coconut WHVWDÀRXURIIRXULQGLJHQRXVFRFRQXWFXOWLYDUVQDPHO\ Gon Thambili (GT), Ran Thambili (RT), San Raman (SR), Tall × Tall (T×T) and commercial hybrid coconut (COM). It is believed that this information would be YLWDOIRUKHOSLQJWRGHYHORSFRFRQXWWHVWDÀRXUDVDUDZ material for nutritional improvement of the Sri Lankan society. 'HVKHOOLQJ 3DULQJ &RFRQXWWHVWD 'U\LQJ 2LOH[WUDFWLRQ METHODOLOGY Coconuts of twelve-month maturity were collected from ¿YHGL൵HUHQWORFDOFXOWLYDUV LH*757657î7DQG COM) maintained at the varietal blocks of the Coconut Research Institute, Lunuwila, Sri Lanka during the period August 2018 to October 2018. Fifty nuts of each cultivar were sampled for seasoning followed by de-husking. Shells of the nuts were removed manually using hammers while de-pairing was done using manually operated knives. The fresh testa of individual cultivars were disintegrated separately to medium size particles using a disintegrator (Unitex Engineers, Sri Lanka). The disintegrated parings were then dried at 70 °C using a cabinet-type dehydrator (Wessberg, Martin, Germany) for 8 hrs. Two kilogram samples of dried coconut testa 2LO 'HIDWWHGPHDO *ULQGLQJ 7HVWDIORXU Figure 1: 3URFHVVÀRZGLDJUDPIRUSURGXFWLRQRIFRFRQXWWHVWDÀRXU )LJXUH3URFHVVIORZGLDJUDPIRUSURGXFWLRQRIFRFRQXWWHVWDIORXU September 2019 Journal of the National Science Foundation of Sri Lanka 47(3)  $QDO\VLVRIFRFRQXWWHVWDÀRXU  Analysis of proximate composition Moisture, crude fat, crude protein and ash content of FRFRQXWWHVWDÀRXUZHUHGHWHUPLQHGDFFRUGLQJWRPHWKRGV described in AOAC (2005) manual. The carbohydrate FRQWHQW RI WKH ÀRXU ZDV FDOFXODWHG E\ WKH GL൵HUHQFH [100- (crude protein + crude fat + ash + moisture+ crude ¿EUH @ Analysis of micro-minerals 'LJHVWLRQRIÀRXUVDPSOHVZDVFDUULHGRXWLQDPLFURZDYH digester (CEM MARS 6, USA) with the addition of 3 mL RI   QLWULF DFLG WR  J RI ÀRXU 7KH GLJHVW ZDV ¿OWHUHGLQWRDP/YROXPHWULFÀDVNDQGPDGHXSWR mark with distilled water. This solution was used for DQDO\VLVRIPLFURPLQHUDOVXVLQJ,&3VSHFWURSKRWRPHWHU 7KHUPRVFLHQWL¿FL&$3VHULHV86$  $QDO\VLVRIIDWW\DFLGSUR¿OH A sample portion of oil (0.4 g) was weighed into a screw capped glass tube and 4.0 mL portion of methanol and 0.1 mL portion of methanolic KOH were added. The mixture was heated to 60 °C in a water bath for 10 min and allowed to cool. Into this, 2 mL portion of hexane and 4 mL portion of distilled water were added. Contents were agitated at 2500 rpm for 10 min in a vortex. After allowing the contents to separate into layers, the upper layer was injected into a gas chromatograph (GC-2010 Shimadzu &RUSRUDWLRQ-DSDQ ¿WWHGZLWKDÀDPHLRQLVDWLRQGHWHFWRU (FID). The temperature of the oven was programmed as follows: the initial temperature was 130 °C (1 min hold), then increased to 170 °C (6.5 °C min-1), 170 °C to 215 °C (2.75 °C min-1) and maintained at 215 °C for 12 min. Thereafter, the temperature was increased from 215 °C to 230 °C (4 °C min-1) and maintained at 230 °C for 3 min. Temperatures of the injector and detector were maintained at 270 °C and 280 °C, respectively. +\GURJHQ ZDV XVHG DV WKH FDUULHU JDV DW D ÀRZ UDWH RI 43 cm/sec. Split ratio of the injector was 50:1. Retention time of each peak was compared with that of standard fatty acid methyl esters to identify individual fatty acids. The percentage of each fatty acid was calculated by dividing the peak area of the individual fatty acid by the total of the peak areas gained for all fatty acids. Statistical analysis All the results from analyses were expressed as the mean value ± standard deviation. Data were statistically analysed by one-way analysis of variance (ANOVA) using Tukey’s test of MINITAB (version 14) statistical package at 0.05 probability level. Journal of the National Science Foundation of Sri Lanka 47(3)  RESULTS AND DISCUSSION Moisture Moisture is the most abundant component of most plant foods and is also a crucial factor to determine the shelflife stability of processed products (Coultate, 2009). According to the data presented in Table 1, the mean PRLVWXUH FRQWHQW RI WKH WHVWD ÀRXU RI FRFRQXW FXOWLYDUV was found to range from 1.8 to 4.6 %. The moisture FRQWHQW RI 65 ZDV VLJQL¿FDQWO\ KLJKHU WKDQ WKRVH RI *7 7î7 DQG 57 7KHUH ZDV QR VLJQL¿FDQW GL൵HUHQFH among the mean moisture contents of GT, T×T and RT. However, the mean moisture content of COM ZDVVLJQL¿FDQWO\ORZHUWKDQWKRVHRI*77î7DQG57 (p < 0.003). When compared with previous reports, the PRLVWXUHFRQWHQWVRIFRFRQXWWHVWDÀRXUXVHGLQWKLVVWXG\ ZHUHORZHUWKDQWKRVHRIFRPPHUFLDOZKHDWÀRXU 1DVLU et al.,   2UJDQLVPV QDWXUDOO\ SUHVHQW LQ WKH ÀRXU VWDUW WR JURZ DW KLJK PRLVWXUHV SURGXFLQJ R൵ RGRXUV DQG ÀDYRXUV +HQFH 1DVLU et al. (2003) suggested that ZKHDW ÀRXU KDYLQJ OHVV WKDQ  PRLVWXUH ZRXOG EH appropriate for extended shelf life. Further, more mold growth and insect infestation has been noticed in wheat ÀRXUKDYLQJKLJKHUPRLVWXUHGXULQJVWRUDJH Protein 3URWHLQV DUH WKH WKLUG PRVW DEXQGDQW FODVV RI macromolecules in food systems; they perform numerous biological functions in living systems (Chang, 1998). According to the data presented in Table 1, WKH PHDQ SURWHLQ FRQWHQW RI WKH WHVWD ÀRXU RI FRFRQXW cultivars was found to range from 23.8 to 32.2 %. The lowest protein content was found with COM while the highest was recorded for GT. However, there was no VLJQL¿FDQW GL൵HUHQFH EHWZHHQ WKH SURWHLQ FRQWHQWV RI RT and SR cultivars. The mean protein content of T×T ZDVVLJQL¿FDQWO\KLJKHUWKDQWKRVHRI5765DQG&20 3UHYLRXVUHVHDUFKHUVKDYHH[DPLQHGWKHSURWHLQFRQWHQW RI GHIDWWHG FRFRQXW ÀRXU REWDLQHG IURP WKH ZKROH endosperm, but not the protein content of the testa. In an early report, Ediriweera and Kashizumi (1991) pointed out that the whole endosperm of fresh coconut has about 4 % protein and the value might increase in defatted meals after extraction of milk. In a study on mixed coconut types, Yalegama and Chavan (2006) IRXQG WKDW FRFRQXW ÀRXU REWDLQHG DIWHU RLO H[WUDFWLRQ of the whole kernel has around 18 to 20 % of protein. According to another report, Beansch et al. (2004) UHSRUWHG WKDW GHIDWWHG FRFRQXW ÀRXU REWDLQHG DIWHU WKH extraction of virgin coconut oil contained about 20 % protein; the value was higher than those reported for September 2019  66.0DUDVLQJKHHWDO FRPPHUFLDOO\PLOOHGZKHDWÀRXUZKLFKFRQWDLQHGDERXW 10.33 % protein. The protein content is an important SDUDPHWHU IRU EUHDG PDNLQJ DV ÀRXU FRQWDLQLQJ KLJKHU SURWHLQ FRQWHQWV ZRXOG EH PRUH H[SHQVLYH WKDQ ÀRXUV Table 1: of lower protein content. Another important feature of FRFRQXWWHVWDÀRXULVWKDWLWVSURWHLQLVJOXWHQIUHHZKLFK is advantageous for people with celiac disease or gluten intolerance. ,QWHUYDULHWDOGL൵HUHQFHVLQSUR[LPDWHFRPSRVLWLRQRIFRFRQXWWHVWDÀRXURIGL൵HUHQWFRFRQXWFXOWLYDUV 3DUDPHWHU Moisture (%) Ash (%) Crude protein (%) Crude fat (%) Total carbohydrates E\GL൵HUHQFH     SR  GT &XOWLYDU RT T×T COM 4.27 ± 0.31c 5.00 ± 0.57c,d 24.69 ± 0.74a 23.49 ± 4.91d 42.55 3.40 ± 0.53b 3.70 ± 0.14a 32.22 ± 2.48c 13.41 ± 4.56c 47.27 3.07 ± 0.11b 5.30 ± 0.14d 25.39 ± 0.25a 13.28 ± 0.06c 52.96 2.80 ± 0.40b 4.20 ± 0.00b 28.37 ± 0.00b 7.93 ± 2.22a 56.7 2.27 ± 0.42a 4.50 ± 0.14c 23.82 ± 0.99a 10.17 ± 1.84b 59.24 (DFKYDOXHLQWKHWDEOHUHSUHVHQWVWKHPHDQRIWKUHHUHSOLFDWHV0HDQVZLWKLQHDFKURZEHDULQJGL൵HUHQWVXSHUVFULSWVDUH VLJQL¿FDQWO\ S GL൵HUHQW SR - San Raman; GT - Gon Thambili; RT - Ran Thambili; T×T - Tall×Tall; COM - commercial hybrid Fat Fatty acid distribution Dietary fat or lipid is one of the most important macronutrients that provides energy and essential fatty acids to various functions of the human body (Raihana et al., 2015). Fat contents of food usually vary from very low to high depending on the source of origin, variety, geographical location, etc. (De Man, 1999). The data presented in Table 1 compared the inter-varietal GL൵HUHQFHV RI IDW FRQWHQW DPRQJ WKH ORFDOO\ DYDLODEOH coconut cultivars. The mean fat content of the testa ÀRXURIFRFRQXWFXOWLYDUVZDVIRXQGWRYDU\IURP to 23.49 %. According to literature, previous researchers KDYHH[DPLQHGWKHIDWFRQWHQWRIFRFRQXWÀRXUREWDLQHG from the whole endosperm, but not the fat content of the WHVWD WR FRPSDUH WKH LQWHUYDULHWDO GL൵HUHQFHV RI ORFDO cultivars. For instance, Yalegama and Chavan (2006) UHSRUWHGWKDWFRFRQXWÀRXUREWDLQHGDIWHURLOH[WUDFWLRQ of the whole kernel had about 10 to 13 % fat. In a separate communication, Beansch et al. (2004) stated WKDWGHIDWWHGFRFRQXWÀRXUREWDLQHGDIWHUWKHH[WUDFWLRQ of virgin coconut oil contained about 12.0 % fat (w/w, dry basis). According to Najwa et al. (2017), the fat content of defatted coconut residue left after extraction of coconut milk was found to be 17.26 %. All these indicated that the method of preparation or the nature of VDPSOLQJ LQ GL൵HUHQW VWXGLHV FRXOG KDYH FRQWULEXWHG WR WKHREVHUYHGYDULDWLRQLQIDWFRQWHQWRIGL൵HUHQWFRFRQXW WHVWDÀRXUVDPSOHV The fatty acid distributions of oils extracted from testa ÀRXURIGL൵HUHQWFXOWLYDUVZHUHFRPSDUHGDVVKRZQLQ Table 2. The oil samples consisted of 88.75–91.23 % saturated fatty acids (SFA) and 8.76–11.19 % unsaturated IDWW\DFLG 86)$ $PRQJWKHGL൵HUHQWFXOWLYDUVODXULF acid was the dominant fatty acid (42.65–45.97 %), followed by myristic acid (19.69–21.46 %) and palmitic acid (9.42–10.24 %). In a previous study reporting the composition of coconut testa oil, lauric acid (42.28 %) was found to be the predominant fatty acid, followed by myristic acid (18.99 %) and palmitic (11.57 %) acid (Zhang et al., 2015). In another study to compare the composition of coconut testa oil and ordinary coconut oil, Marikkar and Nasyrah (2012) observed the proportion of fatty acids in the order of lauric > myristic > palmitic DFLGV+RZHYHUVRPHGL൵HUHQFHVZHUHREVHUYHGLQWKH proportional distribution of fatty acids in the oils of copra testa and wet-coconut testa; they took the order of lauric > myristic > oleic acids (Appaiah et al., 2014). With reference to the report of Appaiah et al. (2014), the mean proportion of lauric acid observed in the present study (44.92 %) was slightly higher than those of copra testa (40.9 %) and wet-coconut testa (32.4 %). When FRPSDUHGWRRLOVIURPFRFRQXWWHVWDÀRXURIWKHSUHVHQW study (7.02 %), copra testa (12.2 %) and wet-coconut testa (17.8 5%) had considerably higher oleic acid contents. However, the mean percentage of myristic September 2019 Journal of the National Science Foundation of Sri Lanka 47(3) $QDO\VLVRIFRFRQXWWHVWDÀRXU   Table 2: ,QWHUYDULHWDOGL൵HUHQFHVLQIDWW\DFLGFRPSRVLWLRQVRIFRFRQXWWHVWDÀRXURIGL൵HUHQWFRFRQXWFXOWLYDUV Fatty acid C8:0 C10:0 C12:0 C14:0 C16:0 C18:0 C18:1 C18:2 SFA USFA SR RT Cultivar GT T×T COM 7.62 ± 0.01b 4.96 ± 0.01c 45.48 ± 0.03b,c 20.25 ± 0b 9.84 ± 0.03b 2.23 ± 0.69a 7.22 ± 0.65a,b 2.38 ± 0b 90.39 ± 0.66b 9.6 ± 0.65a 8.05 ± 0.08c 5.32 ± 0.03d 45.97 ± 0.23c 19.69 ± 0.06a 9.42 ± 0.11a 2.55 ± 0.35a 6.63 ± 0.20a 2.34 ± 0.04b 91.01 ± 0.16b 8.98 ± 0.17a 7.60 ±0.01b 4.72 ± 0.11b 45.23 ± 0.1b 21.46 ± 0.03c 9.55 ± 0.06a 2.66 ± 0.09a 6.27 ± 0.05a 2.49 ± 0.07b 91.23 ± 0.02b 8.76 ± 0.02a 8.14 ± 0.03c 5.21 ± 0.04d 45.29 ± 0.11b 20.2 ± 0.04b 9.43 ± 0.04a 2.52 ± 0.11a 7.09 ± 0.05a,b 2.09 ± 0.04a 90.80 ± 0.08b 9.19 ± 0.08a 7.33 ± 0.01a 4.45 ± 0.03a 42.65 ± 0.21a 21.15 ± 0.21c 10.24 ± 0.04c 2.92 ± 0.02a 7.91 ± 0.01b 3.28 ± 0.02c 88.75 ± 0.06a 11.19 ± 0.01b (DFKYDOXHLQWKHWDEOHUHSUHVHQWVWKHPHDQRIWKUHHUHSOLFDWHV0HDQVZLWKLQHDFKURZEHDULQJGL൵HUHQWVXSHUVFULSWVDUH VLJQL¿FDQWO\ S GL൵HUHQW SR - San Raman; GT - Gon Thambili; RT - Ran Thambili; T×T - Tall×Tall; COM - commercial hybrid C:8 - caprylic; C:10 - caproic; C12:0 - lauric, C14:0 - myristic, C16:0 - palmitic, C18:0 - stearic; C18:1 - oleic; C18:2 - linoleic; SFA - saturated fatty acid; USFA - unsaturated fatty acid acid (20.55 %) in the present study was comparatively similar to those of copra testa (20.9 %) and wet-coconut testa (20.2 %).  7KH LQWHUYDULHWDO GL൵HUHQFHV RI WKH GLVWULEXWLRQ of individual fatty acids among cultivars RT, GT, SR, T×T and COM are of considerable interest in nutrition. Generally, in this study there is no particular pattern of change among the distribution of various fatty acids. 6LJQL¿FDQWGL൵HUHQFHVZHUHQRWLFHGDPRQJWKHFXOWLYDUV with regard to the distribution of fatty acids such as FDSU\OLFDFLGDQGFDSURLFDFLGDOWKRXJKWKHGL൵HUHQFHV were minute. The proportion of lauric acid was highest for RT while the same for COM was lowest. Likewise, the proportion of myristic acid was highest for GT while WKHVDPHIRU57ZDVORZHVW$PRQJDOO¿YHFXOWLYDUVWKH proportions of stearic acid and unsaturated fatty acids such as oleic and linoleic acids were low. As a result, coconut WHVWDÀRXURIWKHVHFXOWLYDUVPLJKWGLVSOD\EHWWHUVKHOI OLIHVWDELOLW\WKDQZKHDWÀRXU,WLVEHFDXVHFRFRQXWWHVWD ÀRXU ZLWK OHVV DPRXQWV RI XQVDWXUDWHG IDWW\ DFLGV WKDQ ZKHDWÀRXUZRXOGEHFRPHOHVVSURQHWRDXWRR[LGDWLRQ In a previous study, Nikolic et al. (2015) reported that the SUHGRPLQDQWIDWW\DFLGRIZKHDWÀRXUZDVOLQROHLFDFLG (66.57 %), followed by palmitic acid (15.36 %) and oleic acid (13.34 %). According to another report by Nikolic et al   WKH PDMRU IDWW\ DFLG RI ZKHDW ÀRXU ZDV found to be linoleic acid (57.67 %), followed by oleic acid (20.28 %) and palmitic acid (19.56 %). Journal of the National Science Foundation of Sri Lanka 47(3) Ash Ash is the composite material of minerals present in ÀRXU 'HWHUPLQDWLRQ RI WKH DVK DQG PLQHUDO FRQWHQW RI foods is important for a number of reasons. For instance, the quality of many foods depends on the concentration and type of minerals they contain, including the taste, DSSHDUDQFHWH[WXUHDQGVWDELOLW\3UHYLRXVVWXGLHVKDYH VKRZQWKDWDVKFRQWHQWRIZKHDWÀRXUYDULHVIURPDERXW 1.50 to 2.00 % (NDSU, 2018). It is generally accepted WKDW WKH DVK FRQWHQW RI ÀRXU GRHV QRW D൵HFW WKH EDNLQJ performance in majority of the cases (Borla et al., 2004). The data presented in Table 1 shows that ash contents of the samples ranged from 3.6 to 5.4 %. Mean ash content RI*7ZDVVLJQL¿FDQWO\ S ORZHUWKDQWKRVHRI 65 57 7î7 DQG &20 +RZHYHU QR VLJQL¿FDQW S !  GL൵HUHQFHVZHUHQRWLFHGDPRQJPHDQDVKFRQWHQWV of SR, RT, T×T and COM. In a previous study, Yalegama et al. (2013) observed the changing pattern of ash content DPRQJFRFRQXWÀRXURUUHVLGXHVDPSOHVREWDLQHGIURP GL൵HUHQW PHWKRGV RI SURFHVVLQJ )RU LQVWDQFH WKH DVK contents of coconut residue samples obtained after milk H[WUDFWLRQ E\ WZR GL൵HUHQW PDFKLQHV ZHUH IRXQG WR EH 1.5 % (Yalegama et al., 2013) and 0.54 % (Najwa et al.,  7KHVHGL൵HUHQFHVFRXOGEHGXHWRWKHGL൵HUHQFHLQ H[WUDFWLRQH൶FLHQFLHVRIWKHWZRPLONH[WUDFWRUPDFKLQHV used by these two groups. However, higher ash content YDOXHVZHUHQRWLFHGIRUFRFRQXWÀRXUREWDLQHGWKURXJK virgin coconut oil extraction. This could probably September 2019  66.0DUDVLQJKHHWDO be because more minerals are washed away during the aqueous exaction of coconut milk, while they are retained with the defatted residue coming from coconut oil extraction. Micro-mineral distribution &RPSDULQJ PLFURPLQHUDO GLVWULEXWLRQ LQ IRRG VWX൵V LV generally important for the assessment of nutritional values. Although they are required in minute quantities, micro minerals are essential to catalyse enzymatic biochemical reactions of various metabolisms. The data presented in Table 3 compares the distribution of PLFURPLQHUDOVSUHVHQWLQWKHFRFRQXWWHVWDÀRXURIWKH cultivars. Mn was the most prevalent mineral (73.71– 94.1 mg/kg), followed by Zn (29.65–57.34 mg/kg) and Cu (29.94–45.14 mg/kg). According to previous studies, whole coconut kernel was known to possess minerals such as Fe, Cu, Mn and Zn (Yalegama et al., 2013). Mn is an essential micro-mineral that acts as a cofactor to many enzymes involved in bone formation and various other metabolic processes. It is said to be present in trace amounts in a variety of food items such as nuts, whole grains, and some vegetables. In this study, Mn content of the samples ranged from 73.71 to 94.1 mg/kg; there was no statistically VLJQL¿FDQW GL൵HUHQFH DPRQJ WKH PHDQ 0Q FRQWHQW RI RT, GT and COM. However, the mean Mn content of 65 ZDV VLJQL¿FDQWO\ S    KLJKHU WKDQ WKRVH RI RT, GT and COM. Meanwhile the mean Mn content RI 7î7 ZDV VLJQL¿FDQWO\ S    ORZHU WKDQ WKRVH of RT, GT and COM. Zn was the next most abundant PLFURPLQHUDOGHWHFWHGLQFRFRQXWWHVWDÀRXURIWKHORFDO FRFRQXWFXOWLYDUV$FFRUGLQJWRVFLHQWL¿FVWXGLHV=QLV WKH FRIDFWRU IRU PDQ\ HQ]\PHV D൵HFWLQJ JURZWK DQG GLJHVWLRQLWVGH¿FLHQF\FDQOHDGWRJURZWKUHWDUGDWLRQ sexual immaturity and impaired immune response (Coultate, 2009). Generally, protein containing foods are a good source of zinc. In this study, Zn contents of the samples ranged from 29.65–57.34 mg/kg. There ZDV QR VWDWLVWLFDOO\ VLJQL¿FDQW S !   GL൵HUHQFH in the mean Zn contents among SR, RT, GT, T×T and COM. The next important micro-mineral is Cu, which plays an important role in several enzymatic reactions (Coultate, 2009). It is a constituent of enzymes such as tyrosinase, cytochrome oxidase, ascorbic acid oxidase, uricase, monoamine oxidase, etc. Legumes, ZKROHJUDLQVQXWVVKHOO¿VKDQGVHHGVDUHVRPHRWKHU sources that provide Cu in human nutrition. Since Cu is a transition metal, citrus fruit juices might help Cu DEVRUSWLRQWKURXJKPHWDOFKHODWLQJH൵HFW$FFRUGLQJWR 7DEOH&XFRQWHQWVRIFRFRQXWWHVWDÀRXURIFXOWLYDUV were found to range from 29.94–45.14 mg/kg. The mean Cu content was highest for RT while the mean Cu content decreased in order of RT, SR and GT in a VWDWLVWLFDOO\ VLJQL¿FDQW S    PDQQHU +RZHYHU WKHUH ZDV QR VLJQL¿FDQW GL൵HUHQFH EHWZHHQ WKH PHDQ Cu content of T×T and COM. The data presented in Table 3 shows that Fe contents of the samples were in the range of 0.48–2.6 mg/kg. Fe is an essential mineral for hemoglobin and myoglobin, which are part of the oxygen transport system of the human body. Iron EDODQFHLVDOVRFULWLFDOIRUEUDLQIXQFWLRQWKHGH¿FLHQF\ might lead to tiredness, fatigue and anemia (Coultate,  5HGPHDWV¿VKSRXOWU\HJJVDQGOHJXPHVDUH Table 3: ,QWHUYDULHWDOGL൵HUHQFHVLQPLQHUDOFRPSRVLWLRQRIFRFRQXWWHVWDÀRXURIGL൵HUHQWFXOWLYDUV Mineral element Ni (mg/kg) Zn (mg/kg) Mn (mg/kg) Cr (mg/kg) Co (mg/kg) Cu (mg/kg) Fe (mg/kg) Ba (mg/kg) Mo (mg/kg) SR RT Cultivar GT T×T COM 6.54 ± 0.67c 46.7 ± 6.50b 93.82 ± 0.38d 6.78 ± 0.65 0.15 ± 0.57 38.7 ± 0.70 2.60 ± 0.16c 1.1 ± 0.02c 0.26 ± 0.01b 6.69 ± 1.5c 54.5 ± 4.00c 89.20 ± 0.41c 7.56 ± 0.32 0.21 ± 0.03 44.7 ± 0.70 1.38 ± 0.41b 1.19 ± 0.11c 0.31 ± 0.08b 3.17 ± 78.4b 44.5 ± 8.50b 85.62 ± 3.02b 1.97 ± 0.02 0.11 ± 0.00 34.8 ± 0.90 0.91 ± 0.64a 0.52 ± 0.09b 0.12 ± 0.00a 2.12 ± 0.10a 33.4 ± 5.30a 75.30 ± 2.25a 0.68 ± 0.02 0.07 ± 0.01a 30.5 ± 0.80a 0.48 ± 0.26a 0.36 ± 0.10a 0.12 ± 0.01a 3.89 ± 0.04b 36.2 ± 0.70a 83.60 ± 1.43b 0.35 ± 0.02a 0.16 ± 0.00 31.0 ± 0.70a 0.61 ± 0.00a 0.51 ± 0.03b 0.09 ± 0.03a (DFK YDOXH LQ WKH WDEOH UHSUHVHQWV WKH PHDQ RI WKUHH UHSOLFDWHV 0HDQV ZLWKLQ HDFK URZ EHDULQJ GL൵HUHQW VXSHUVFULSWV DUH VLJQL¿FDQWO\ S GL൵HUHQW SR - San Raman; GT - Gon Thambili; RT - Ran Thambili; T×T - Tall×Tall; COM - commercial hybrid September 2019 Journal of the National Science Foundation of Sri Lanka 47(3) $QDO\VLVRIFRFRQXWWHVWDÀRXU  usually good sources of Fe. The mean Fe contents of RT (1.38 ± 0.41 mg/kg), GT (0.91 ± 0.64 mg/kg), T×T (0.48 ± 0.26 mg/kg) and COM (0.61 ± 0.00 mg/kg) were PRUH RU OHVV HTXDO EXW VLJQL¿FDQWO\ ORZHU S    than that of SR (2.60 ± 0.16 mg/kg). Total carbohydrate content Total carbohydrates consist of multiple nutrients, which LQFOXGH GLHWDU\ ¿EUH VXJDUV DQG VWDUFKHV 7KH GDWD presented in Table 1 compares the total carbohydrate FRQWHQWVRIFRFRQXWWHVWDÀRXUREWDLQHGIURP¿YHORFDO coconut cultivars. The total carbohydrate contents of the samples were found to range from 59.24–42.55 %; the mean total carbohydrate content was lowest for SR variety, while the highest value of the same was recorded IRU &20 7KH LQWHUYDULHWDO GL൵HUHQFHV RI WRWDO FDUERK\GUDWHV DPRQJ WKH FXOWLYDUV ZHUH VLJQL¿FDQWO\ S GL൵HUHQW7KHFDUERK\GUDWHFRQWHQWRIFRFRQXW WHVWDÀRXULVJHQHUDOO\ORZHUWKDQWKDWRIWUDGLWLRQDOJUDLQ ÀRXUVVXFKDVZKHDWÀRXU.DVVHJQ  UHSRUWHGWKDW  J RI ZKHDW ÀRXU PLJKW FRQWDLQ DURXQG ± J RI carbohydrates while David et al. (2015) found that the WRWDOFDUERK\GUDWHFRQWHQWRIVRIWZKHDWÀRXUZDVDURXQG 83 %. According to previous reports of Yalegama and Chavan (2006), the total carbohydrate content of coconut ÀRXUZDVDURXQG,QDVHSDUDWHVWXG\%HDQVFKet al. (2004) also reported that the total carbohydrate content RI GHIDWWHG FRFRQXW ÀRXU REWDLQHG DIWHU WKH H[WUDFWLRQ of virgin coconut oil was about 52.0 % (w/w, dry basis). The occurrence of higher proportions of fat and SURWHLQLQFRFRQXWÀRXUZRXOGEHDUHDVRQIRUWKHORZHU proportion of total carbohydrates. In addition, the quality RIFDUERK\GUDWHLVDOVRGHSHQGHQWRQLWV¿EUHFRQWHQWDQG JO\FHPLF LQGH[ $V LW FRQWDLQV HQRXJK ¿EURXV PDWWHU it can also be useful as a thickening agent in sauces or soups. In a previous study, Leelavathi and Rao (1993) UHSRUWHGWKDWZKHDWÀRXUFRQWDLQHGDORZDPRXQWRIWRWDO GLHWDU\ ¿EUH DQG WKHUHIRUH VXSSOHPHQWDWLRQ RI ZKHDW ÀRXU ZLWK GHIDWWHG FRFRQXW ÀRXU FRXOG LQFUHDVH WKH GLHWDU\¿EUHFRQWHQWRIIRRGIRUPXODWLRQV CONCLUSIONS ,Q WKLV VWXG\ LQWHUYDULHWDO GL൵HUHQFHV RI FKHPLFDO composition and nutritional properties of coconut testa ÀRXU RI GL൵HUHQW LQGLJHQRXV FXOWLYDUV ZHUH FRPSDUHG ,QJHQHUDOFRFRQXWWHVWDÀRXURIDOOFXOWLYDUVGLVSOD\HG KLJKHU FRQWHQWV RI SURWHLQ DQG IDW WKDQ ZKHDW ÀRXU KHQFH SDUWLDO VXEVWLWXWLRQ RI ZKHDW ÀRXU ZLWK FRFRQXW WHVWD ÀRXU ZRXOG LPSURYH WKH QXWULWLRQDO TXDOLW\ RI ÀRXUEDVHGSURGXFWV$PRQJWKHGL൵HUHQWFXOWLYDUVWKH Journal of the National Science Foundation of Sri Lanka 47(3)  highest protein content was observed in GT while the lowest protein value was observed for COM variety. The highest fat content was noted in SR while least fat content was found in T×T. The maximum ash content was found in RT while the lowest ash content was in GT variety. COM hybrid had the highest carbohydrate content while the lowest carbohydrate content was UHFRUGHGIRU65YDULHW\,QJHQHUDOFRFRQXWWHVWDÀRXU of all cultivars contained micro-minerals such as Mn, &X DQG =Q 7KHUH ZHUH QRWLFHDEOH FXOWLYDU GL൵HUHQFHV with regard to mineral composition. Highest amounts of Fe and Mn were present in SR while the highest content of Cu and Zn were found with RT. All these ¿QGLQJV VXJJHVW WKDW FRFRQXW WHVWD ÀRXU FDQ EHFRPH D potential source for value addition purposes and reduce the wastage of under-utilised coconut testa generated by the coconut processing sector. Acknowledgements Authors gratefully acknowledge provision of coconut samples and analytical services by the Coconut Research Institute of Sri Lanka. REFERENCES AOAC International (2005). 2৽FLDO 0HWKRGV RI $QDO\VLV RI $2$& ,QWHUQDWLRQDO, 18th edition. 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Studies on utilization RIFRFRQXWÀRXUDVDVRXUFHRIFHOOZDOOSRO\VDFFKDULGHV 7URSLFDO$JULFXOWXUDO5HVHDUFK 18: 126–134. =KDQJ< =KHQJ< 'XDQ .  *XL 4   3UHSDUDWLRQ DQWLR[LGDQWDFWLYLW\DQGSURWHFWLYHH൵HFWRIFRFRQXWWHVWDRLO extraction on oxidative damage to human serum albumin. ,QWHUQDWLRQDO-RXUQDORI)RRG6FLHQFHDQG7HFKQRORJ\ 51: 946–953. DOI: https://doi.org/10.1111/ijfs.12945 Journal of the National Science Foundation of Sri Lanka 47(3)