Chemical Composition And Physicochemical Properties Of Squash .
Contemporary Engineering Sciences, Vol. 11, 2018, no. 21, 1003 - 1012HIKARI Ltd, 8384Chemical Composition and PhysicochemicalProperties of Squash (Cucurbita moschata)Cultivated in Bolivar Department (Colombia)Somaris E. Quintana1, R. M. Marsiglia2, Diana Machacon1,Edilbert Torregroza2 and Luis A. García-Zapateiro11Faculty of Engineering, Food Engineering Program, Group of Investigation inEngineering of Complex Fluids and Food Rheology (IFCRA)University of Cartagena, Cartagena, Colombia2Social Sciences and Education FacultyUniversity of Cartagena, Cartagena, ColombiaCopyright 2018 Somaris E. Quintana et al. This article is distributed under the CreativeCommons Attribution License, which permits unrestricted use, distribution, and reproduction in anymedium, provided the original work is properly cited.AbstractThe present work has evaluated the morphological, chemical and physicochemicalproperties of three components of squash (the peel, pulp and seed). Proximatecomposition and physicochemical properties of oil were performed according toAOAC procedures. Different morphological characteristics showed considerablesimilarities among different cultivars from Bolivar department (Colombia). Thehigher moisture and carbohydrate contents were established in the pulp with 85.34% and 81.45 %, and the peel with 81.06 % and 79.23 %, respectively. On the otherhand, the seeds had higher amounts of oils and proteins with 25.70 % and 52.6,respectively. The Fourier transform infrared spectroscopy (FTIR) spectrum showedrelations with the functional groups of the different vegetal parts with their chemicalcomposition. Considering the proximate composition in the different part of squashappear to be quite promising technological and commercial exploitation.Keywords: Squash (Cucurbita moschata), chemical composition, physicochemical, peel, seed, pulp
1004Somaris E. Quintana et al.IntroductionSince ancient times, native vegetables and tropical fruits have been used inaccordance with the empirical knowledge of the relevant communities. Fruits havevarious uses, from gastronomic, industrial and pharmaceutical points of view. Thereis a lack of the scientific and technical aspects of some varieties of fruit andvegetables, which has potentially caused wasted opportunities in terms of sourcesof foodstuffs, raw materials and even medicines. In recent years, the relationshipbetween fruit and vegetable intake and health has been the focal point of scientificinvestigations with the aim of identifying the specific plant components thatcontribute to well-being [1]. Squash is an annual herbaceous plant belonging to thefamily Cucurbitaceae; it is widely cultivated and has been used as food sinceancient times. It is an economically important and diverse crop species of vegetablein the genus Cucurbita. It is grown commercially in fields as well as domesticgardens and is native to the Americas. Cucurbita sp. crops have of great incidenceand importance in the Bolívar Department (Colombia), where this vegetablepresents an essential product for inhabitants’ food safety [2]. There is evidence thatshows it was introduced to Europe in the 16th century [3] Squash (Cucurbitamoschata) is widely cultivated throughout the world but especially in tropicalregions. It is highly appreciated due to its nutritional value, its sensorycharacteristics and digestive effects [4]. The fruit is frequently used as an ingredientin pies, soups, stews, and bakery preparations. The seeds are a common snack foodin several cultures and the seed oil has culinary and pharmaceutical uses. In themarket, there has been an increase in products derived from squash, both in the foodand in the cosmetic industries. Therefore, there is an important quantity of peel andpulp by-products that have great potential for exploitation in the future.The consumer preference for summer squash is greatly influenced by its externalappearance, constituting the main physical property. Moreover, information on thesoluble solid content and individual carotenoids in fruits could help increase thedietary intake for consumers. Thus, recently, because of the high antioxidantactivity and nutritional properties of squash, the ready-to-eat winter squash snackwas developed with a high carotenoid content and good sensory properties [5]. Dueto the increasing acceptance and commercialization of the products derived fromfruits and vegetables, more extensive scientific information about thecharacteristics of this fruit is required. For this reason, the study of the chemical andphysicochemical properties of squash is of interest, to aid the characterization anduse in the development of new productsThe purposes of this study were to determine the chemical and physicochemicalproperties of the pulp, seeds and peel of squash. This study is part of thecontinuation in the application of Geographic Information Systems forcharacterization of preharvest and postharvest factors of Squash (Cucurbita sp.) inBolívar Department, Colombia [2].
Chemical composition and physicochemical properties1005Material and methodsPlant materialSquashes (Cucurbita moschata) with a similar maturity and weight were cultivatedat Bolivar department (Colombia). The fruits were washed and peeled. The seedsand peel were dried at room temperature for 72 hours and then ground in a mill IKAMF 10 (from IKA-Werke GmbH & Co. KG). The pulp was crushed by mechanicalshear, using a KitchenAid food processor for 2 minutes in order to obtain ahomogeneous natural pulp. The samples were vacuum packed in small plastic bagsand stored at -4 ºC until further analysis.Physical propertiesThe weight of whole fruits and seeds was evaluated from samples of squash. Theedible rate was calculated as the weight percentage of pulp to the whole fruit. Twomeasurements were made for each fruit and a mean value was obtained from themeasurements of a total of fifteen fruit. The following analysis was carried out foreach harvesting time and maturity stage: fruit was randomly chosen to create tenbatches of eight, visually presenting the same high-quality appearance in theirphysical characteristics (homogeneous color, size, and without wrinkling). Eachbatch was considered to be replicate.Physicochemical and bromatological characterizationThe physicochemical and bromatological analysis was carried out on a dried basis.Soluble solids were measured with an Abbé refractometer (Milton Roy Co., USA)and represented as Brix; the pH of the solution was recorded using a digitalpotentiometer (Orion , USA). All analyses were carried out in triplicate on ripefruit. The ash, moisture, total sugar, oil and protein content of the samples weredetermined according to the standard methods described in Association of OfficialAnalytical Chemists [6].Fourier transform infrared spectroscopy (FTIR)The characterization of the peel, seed and pulps of squash were carried out by meansof Fourier transform infrared spectroscopy (FTIR). FTIR spectra were obtainedwith a Spectrum 400 model (Perkin Elmer) apparatus. Samples were lyophilizedwith a FreeZone 2.5 Liter -50C Benchtop Freeze Dryer and milled. A small samplewas placed between two KBr disks (32 mm x 3 mm in size) and then placed into anappropriate sample holder. The spectra were obtained for a wavelength range of500 – 4000 cm-1 at 4 cm-1 resolution, in the transmission mode. The analyses wereperformed in triplicate and the average spectra used.Results and DiscussionMorphological propertiesThe shape and firmness of the flesh and skin are important features of squashquality, as well as chemical content. Different morphological characteristics (such
1006Somaris E. Quintana et al.as fruit shape, apex, base and skin) showed considerable similarities amongdifferent cultivars at Bolivar (Colombia). Fruit shape varied (oval, long, ovate,round) for different cultivars and strains whereas, the stem end cavity was small,medium or large in size on a visual basis. The summer squash can be harvested overa wide range of sizes, from 50 g to 400 g, the acceptable size range beingdetermined by market demand [7]. A lot of pumpkins (Cucurbita pepo, Cucurbitamaxima) have oval or oblate fruit that are rounded or flat at the ends; scallopsquashes have almost discoidal shaped fruit with undulations or equatorial margins;vegetable marrows have short, cylindrical fruit that are slightly broader at the apex,with a smooth rind which hardens and thickens on ripening and zucchini hascylindrical fruit. These differing fruit shapes result in differential adaptations tovarious methods of culinary preparation [3]. The squash weights ranged from 575.4g to 1561.3 g, the lengths ranged between 16.4 cm and 29.0 cm and the diameterswere from 8.5 cm to 11.3 cm. The samples were cut and peeled and then the peel,seeds and pulp were obtained. The peduncle comprised 0.29% of the wholevegetable. 10.11% was peel, 71.50% pulp and 3.11% seeds. The seeds consisted of36.93% of hull and 63.06% of kernel.Physicochemical and bromatological characteristicsThe physicochemical and bromatological composition of the pulp, seeds and peelof squash are shown in Table 1. The differences in fruit composition depend onmany factors such as the variety, stage of maturity, soil fertility, climate and culturalpractices, among others[8]. The pH values were approximately 6.84 for the rawpulp, 8.50 for the seeds and 6.87 for the peel. This is an important parameterassociated with protein solubility [9]. The pH of a food is used as an indicator ofbacterial spoilage (i.e. food with a high pH is more susceptible to microbialspoilage) [10]. The pH of squash pulp and peel present values close to neutral but,in the case of seeds, it was the basic for considering the vegetable to be lesssusceptible to microbial spoilage. Total solids represent the amount of dry materialremaining after all the water has been evaporated [11] and soluble solid content isused as a maturity index for some fruits. The soluble solids were expressed in ºBrix,with values of 10.46% 0.45 for peel, 1.40% 0.11 for seeds and 5.01% 0.12for the pulps. The pulps have higher moisture contents (85.34% 0.265) than thepeel (81.06% 0.260) and seeds (23.59% 0.700). The higher moisture content ofthe pulps is an indication of the susceptibility of the fruit to microbial attack andspoilage and it is related to the stability. For that reason, the pulp of the squashesshould be dried for storage [12]. A comparison of the proximal composition ofCucurbita pulps, seeds and peel revealed that the moisture of the pulps was inagreement with the data reported by other authors: 79.00 to 93.00 % for Cucurbitamoschata [13], 96.77% for Cucurbita pepo and 94.23% for Cucurbita maxima. Themoisture content of the squash peel was higher than the value reported forCucurbita maxima (75.68) and lowest for Cucurbita pepo (93.59%) [14].
Chemical composition and physicochemical properties1007Table 1. Chemical and physicochemical properties of squash (Cucurbitamoschata).PulpSeedpH6.84 0.0078.5 0.014Soluble solids ( Brix)5.01 0.0701.40 0.110Moisture %85.34 0.26523.59 0.700Ash (%wb)0.70 0.1557.028 0.194Protein (%wb)1.32 0.09825.70 0.403Oil (%wb)0.77 0.01052.6 0.010Total sugar (%db)1.83 0.180 0.05Total carbohydrate (%db)81.45 2.54069.94 2.170*Expressed in (%db) dry basis, (%wb) weight basisPeel6.87 0.01010.46 0.45081.06 0.2603.67 0.0101.78 0.0427.62 0.010 0.0579.23 1.470The seeds contained the highest percentage of protein, oil and ash (25.70% 0.403,52.6% 0.01 and 7.028% 0.194, respectively), followed by the peel (1.78% 0.042, 7.62% 0.01 and 3.67% 0.01), and the pulp (1.32% 0.098, 0.77% 0.01and 0.70% 0.155). In the case of carbohydrate content, the results obtained wereinversely proportional: the pulp had the highest percentage (81.45% 2.54),followed by the peel (79.23% 1.47) and then the seeds (69.94% 2.17). Theseresults were agreed with previous studies [13], [15 – 18]. The ash and proteincontent of the pulps were found to be higher than the results reported by JacoboValenzuela et al., (2011) [3], for Cucurbita moschata, Cucurbita pepo andCucurbita maxima. The oil content was higher than Cucurbita pepo (0.034%) butlower than Cucurbita maxima (0.420%) [14]. The seeds of the squash presentedmoisture, ash and oil contents higher than Cucurbita pepo Subs. Pep Var. Styriaka(5.020%), Cucurbita pepo (7.406%) and Cucurbita maxima (2.75%). The proteinpercentage was higher than Cucurbita pepo Subs. Pep Var. Styriaka (25.40%) andCucurbita pepo (30.883%) but lower than Cucurbita maxima (27.485%) [14], [19– 21]. The ash and protein contents of peel were lower than Cucurbita pepo (0.630%and 0.925%) and Cucurbita maxima (1.396% and 1.130%). The oil was higher thanCucurbita pepo (0.471%), but lower than Cucurbita maxima (0.869%) [14].Chemical characterization of squashAs previously reported [22], FTIR spectroscopy is an appropriate and sensitivetechnique for monitoring quality control in the food industry because it allows arapid screening and quantification of components and, therefore, allows a highthroughput of samples. Most chemical bond components have vibrationalmovements in the medium infrared spectrum (4000 – 650 cm-1), such as lipids,proteins, carbohydrates and nucleic acid molecules [23], [24]. As can be observedin Figure 1, the FTIR spectra of lyophilized samples of squash peel (Sample (a)),seed (Sample (b)) and the pulp (Sample (c)) lie in the wavelength range: 4000–500cm-1. The frequency range of 3000–2800 cm 1 is due to CH stretching absorptions,the carbonyl absorption of the triacylglycerol ester linkage at 1744–1739 cm 1, the
1008Somaris E. Quintana et al.bands associated with the fingerprint region (1500–1000 cm 1), CCH bendingvibration of trans double bonds at 990–950 cm 1 and the overlapping of themethylene rocking vibration and the out-of-plane bending vibration of cissubstituted olefins at 723 cm 1 [25]. The peel (a) presented a band range at 35003200 cm-1 and 1800 cm-1 relating to oxygenated functional groups (O-H), ketones,aldehyde and carboxyl acids of carbohydrate. The bands at 1100–1000 cm-1 relateto esters of lipids and 3000–2900 cm-1, 1300 cm-1 and 700–500 cm-1 correspond tomethyl and methylene of amino acids. In the seeds (b), the band range of 3100–3030 cm-1 is associated with amide B (N-H), the bands at 3300 cm-1 correspond togroups of amide A (N-H), 1660 cm-1 and 1630 cm-1 to amide I (C O; C-N; N-H),1545 cm-1 to amide II (N-H; C-N) and 1300–1230 cm-1 to amide III (which wasassociated with their amino acid contents).% TransmissionFigure 1. FTIR spectra of squash (Cucurbita moschata) a) peel, b) seed and c)pulp.c) Pulp% 100b) Seeda) Peel350030002500200015001000500-1Wavenumber (cm )Proteins are represented in the band range 1700–1650 cm-1 (C O of terminal groupsCOOH of polypeptides). The band near to 1700cm-1 corresponds to the carboxylgroup (C O stretching) that are localized at the ends of the proteins. The band rangeof 3300–3200 cm-1 represents the esters of lipids. The pulps (c), show a band at3400 cm-1 corresponding to carboxyl groups (C( O)OH) and 1500 cm-1 toaldehydes and ketones (R-OH) of carbohydrate. The band range at 3000–2900 cm1conform to methyl and methylene of amino acid and the wave range of 1900–1800cm-1 and 1100–1000 cm-1 to esters of lipids.
Chemical composition and physicochemical properties1009ConclusionsSquash (Cucurbita moschata) is a vegetable with different morphologicalcharacteristics and it has been cultivated at Bolivar department (Colombia). Thepulps and peels have a high percentage of carbohydrate and the seeds arecharacterized by a high amount of oil and protein. The functional groups wereidentified and correlated with FTIR, the pulp and peels with carbohydrate contentand the seeds with protein and lipids. The results of this project corroborate andpromote the use of physicochemical properties and the chemical composition of thesquash, as raw materials of national interest to be used for the preparation of newproducts and the extraction of microcomponents with technological functionality.Acknowledgements. This work is part of a research project "Basic and appliedresearch projects in the agricultural sector (667 of 2014); Project 0487-2014 code1107-667-44997" sponsored by the Administrative Department of Science,Technology, and Innovation (CTeI) - Colciencias (Colombia). The authors aregrateful for their financial support.References[1]H. Palafox-Carlos, E. M. Yahia and G. A. González-Aguilar, Identificationand quantification of major phenolic compounds from mango (Mangiferaindica, cv. Ataulfo) fruit by HPLC–DAD–MS/MS-ESI and their individualcontribution to the antioxidant activity during ripening, Food Chem., 135(2012), no. 1, 105–111. . M. Marsiglia-Fuentes, E. Torregroza Fuentes, S. E. Quintana and L. A.Garcia-Zapateiro, Application of geographic information systems forcharacterization of preharvest and postharvest factors of squash (Cucurbitasp) in Bolivar Department, Colombia, Indian J. Sci. Technol., 11 (2018), no.9, 1–10. H. Paris, Characterization of the Cucurbita pepo collection at the Newe Yaâ TM ar Research Center , Israel, Plant Genetic Resources Newsl., 216 (2001),41–45.[4]J.-V. Noelia, M.-J. Mario Roberto, Z.-M. José de Jesús and G.-I. José Alberto,Physicochemical, technological properties, and health-benefits of Cucurbitamoschata Duchense vs. Cehualca: A Review, Food Research International,44 (2011), 2587-2593. https://doi.org/10.1016/j.foodres.2011.04.039[5]D. Konopacka, A. Seroczyńska, A. Korzeniewska, K. Jesionkowska, K.Niemirowicz-Szczytt and W. Płocharski, Studies on the usefulness ofCucurbita maxima for the production of ready-to-eat dried vegetable snacks
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1012Somaris E. Quintana et al.[25] M. D. Guillén and N. Cabo, Characterization of edible oils and lard by fouriertransform infrared spectroscopy. Relationships between composition andfrequency of concrete bands in the fingerprint region, J. Am. Oil Chem. Soc.,74 (1997), 1281-1286. https://doi.org/10.1007/s11746-997-0058-4Received: March 21, 2018; Published: April 19, 2018
Chemical composition and physicochemical properties 1005 Material and methods Plant material Squashes (Cucurbita moschata) with a similar maturity and weight were cultivated at Bolivar department (Colombia). The fruits were washed and peeled. The seeds and peel were dried at room temperature for 72 hours and then ground in a mill IKA
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