Chemical Composition Of Natural Juices Combining Lemon And Dates - IJFE

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International Journal of Food Engineering Vol. 2, No. 1, June 2016Chemical Composition of Natural JuicesCombining Lemon and DatesSulaiman M. AlfadulKing Abdulaziz City for Science and Technology (KACST), Riyadh, Saudi ArabiaEmail: H. HassanDepartment of Agricultural Engineering, College of Food and Agriculture Sciences, King Saud University, Riyadh,Saudi ArabiaEmail:, with 60 cultivars considered to be the mostpopular and most predominant.Citrus (Citrus lemon L.) fruits are very importantagricultural products in many countries including theKingdom of Saudi Arabia. Citrus fruit is very populardue to its distinctive flavor, taste, and aroma as well asmultiple health benefits associated with it. Theconsumption of citrus fruits or their products is believedto have beneficial effects against a number of diseases,the main reason being the presence of bioactivecompounds [16], [17]. It is well known that ascorbic acidand carotenoids are found in abundance in citrus fruits[18], which play an important role in causing resistanceagainst many diseases. Ascorbic acid content of somelemon juices has been reported to be as high as 680mg L1 of juice and this trait is affected by growing conditions,maturity of the fruit when picked, and the length of fruitstorage period [18]. The international increase in fruitconsumption can be considered as a trend that affectsfruit processing industry. This increase in consumption offruits can be attributed to the increase interest innutritious and healthier food whether in fresh orprocessed forms [19].Dates industry in Saudi Arabia is composed of 132date packaging and processing factories, consumingapproximately 370 million Kg of dates annually; thisrepresents 34.52% of the total dates production [20].Most of these factories produce packaged dates and datespaste. Very few factories produce dates syrup. The datesindustry in the kingdom is looking to diversify datesprocessing activities through the utilization of theoverwhelming advances in food technology.Several researchers investigated the extraction of datesjuice and the production of concentrated dates syrup,known in Arabic as dates Dibbs [5], [8], [10]. Theextraction of clarified dates juice from dates paste or depitted dates flesh is one of the important operationsnecessary for the production of dates juice. The properextraction temperatures and mechanical mixing canincrease the extraction rates of soluble solids byincreasing the mass diffusion coefficient of the solvent(water) inside solid particles. Thus, the efficiency of theextraction process is increased [20], [21].Abstract—In this work, clarified date juices were producedfrom three date fruit cultivars. Basic physical propertiesand chemical composition of dates were experimentallydetermined. Dates juices were flavored with natural lemonjuice, which was added at 0%, 5%, and 10% by weight. Allof the produced dates juices were characterized for theirchemical composition. The addition of natural lemon juice,particularly at 10% (w/w), significantly affected thecomposition of dates juices. The analysis of variance ofdates juices revealed that the addition of lemon juice hadsignificant impacts (P 0.05) and that the effects of the typeof dates and the interaction between the type of dates andthe addition of lemon juice were insignificant. Index Terms—dates, lemon juice, natural juice, chemicalcompositionI.INTRODUCTIONDue to dates’ nutritional, economic and distinctmedicinal properties, it is a common diet source formillions of people in Middle East and around the world[1]-[3] Dates are rich in sugars (fructose, glucose, andsucrose), minerals (potassium, calcium, magnesium,phosphorous, and manganese), vitamins (particularly Aand D), and natural fibers. Several value added productshave been prepared from dates such as dateconfectionaries, bakery products, preserved foods, jams,marmalades and jellies, and breakfast cereals [4]-[9].Dates are rich in carotenoids, polyphenols especiallyphenolic acids, isoflavons, lignans, flavonoids, tannins,and sterols [8], they have been used in folk medicine fortreatment of various infectious diseases such asatherosclerosis [10] diabetes, hypertension, and cancer,and as antifungal, antibacterial and immunomodulatory[11]-[13]. Saudi Arabia is the second largest dateproducer in the world. Dates production representsapproximately 55% of the total fruit production in theKingdom and 13.8% of the total world production [14],[15]. There are 450 different date cultivars in the Manuscript received July 29, 2015; revised January 2, 2016. 2016 International Journal of Food Engineeringdoi: 10.18178/ijfe.2.1.9-159

International Journal of Food Engineering Vol. 2, No. 1, June 201630 minutes for homogenization. Then, the homogeneousdates paste-water suspension was filtered using a framesheet filter (Pilot A 20Z, Seitz-werke Gmbh, Germany).The clarified juices were collected into stainless steeltanks equipped with a controlled mechanical mixer andan electrical heater with a temperature controller. Oncethe filtration process was complete, the collected clarifieddates juices were mechanically mixed. The juices wereheated to 90 C and kept at this temperature for 3 minutesto assure manual pasteurization. The pasteurized datesjuices were immediately cooled to a final temperature of25 C in a double jacketed, stainless steel vessels with10 C water. The juices were poured into pre-sterilizedglass jars (1 L capacity) and tightly closed. The juiceswere then kept in a refrigerator for analysis.The selected Lemon fruits were at mature stage, theywere cut into halves and their juice was squeezed with asqueezer until all the juice was recovered. The juice waspassed through a cheese cloth and samples were taken forphysicochemical analysis. The bulk of the juice wasstored frozen (20 C) until use.Chiara et al. [22] had investigated the characteristicsof dates juice extracted from Diglet Nour dates. Thesecharacteristics were yield, pH, total soluble solid content,minerals, carbohydrates, vitamins, yeast, mold and fungi,and total aerobic microorganisms. The best dates juiceproduced by the investigators contained 2.13g/l citricacid, 0.08% phosphorous on a dry basis, and 26.5, 39.6and 185.9g/l of glucose, fructose and sucrose,respectively. All of the produced juices satisfiedmicrobial health requirements. Several attempts weremade by El-Shaarawy et al. [23] to prepare dates drinksbased on dates juices. These authors concluded that datesjuices need supplementation with organic acids andvarious flavors to produce products acceptable toconsumers. The mixed juices are produced from mixturesof fruits pulps or juices, they are prepared with the aim ofenhancing the nutritional value of a product [19]. This isan area to be investigated thoroughly by those in thedates processing industry. Several studies on mixtures offruit juices have been carried out over the years [24]-[28].Dates are characterized by their low ascorbic acidcontents and high sugar contents, therefore, it isnecessary for developing healthy mixed dates juices, is todetermine the ideal ascorbic acid content of the juice. Themixing of the juice may also improve aroma, taste andnutrient content of the drinks. Hence, mixing dates juicewith lemon juice which is a good source of vitamin C andother bioactive compounds can be helpful in improvingthe nutritive value of dates juice.Therefore, the aim of this study was to develop andevaluate high quality natural dates juices utilizing thenutritional characteristics of both dates and lemon fruits.C. Physical Properties of Raw DatesA random sample of 50 fruits from each type of dateswas examined for fruit mass, length, diameter, pit massand pit mass ratio. A sensitive balance (Mettler ToledoSensitive Balance, Switzerland) was used to measurefruit and pit mass. A digital caliper with a sensitivity of0.01mm (Absolute Digimatic, Mitutoyo, Japan) was usedto measure length and diameter.D. Chemical Composition of Dates Flesh and JuiceBasic physical properties of dates from the threecultivars, Sukkari(S), Khlass(K), and Rezaiz(R), wereexperimentally determined at room temperature (23 C).The standard AOAC methods [29] were used to analyzeall dates flesh and juice samples.II. MATERIALS AND METHODSA. MaterialsThree commercially popular Saudi dates (Sukkari(S),Khlass(K) and Rezaiz(R)) fresh lemon (Citrus lemon L.)were purchased from local market in the city of Riyadh,Saudi Arabia. Dates were manually sorted, washed andcleaned using distilled water. The cleaned, sorted dateswere spread in trays and left to dry at room temperaturein the laboratory at the Department of Food Science andNutrition, College of Food and Agriculture Sciences,King Saud University. The dates were packaged into 3 kgcartons internally lined with a polyethylene bag and wererefrigerated at 5 0.5 C.E. pH, Titratable Acidity and Total Soluble SolidsMeasurement of Lemon JuicepH, Titratable Acidity (TA), and Total Soluble Solids(TSS) were evaluated as quality indexes. The pH wasmeasured using a pH meter (Model: pH meter 240,Corning Scientific Products, NY, USA). The TA wasdetermined by titrating 2ml of the mixture (rising 60mlfinal volume with distilled water) with 0.1 N NaOH (pH8.1). Results were expressed as g citric acid per 100 ml ofsample, in accordance with AOAC [29]. The TSScontents were recorded using a Digital Refractometer(Model: Abbe Mark II, Cambridge Instrument, INC.Buffalo, NY, USA), with values being expressed as Brix.The machine was standardized using purified waterbefore taking readings.B. Samples PreparationFor each of the three dates (S, K and R) 15kg of fruitswere obtained. Dates were manually de-pitted with sharpknives. The dates’ flesh was then transformed to dates’pastes using an electrically driven mincer (Model VEKL1-IEC-34, Italy). Samples were then transferred to astainless steel tank equipped with a controlledmechanical mixer and an electrical heater with atemperature controller (Model D B60A, Seitz Enzinger,Germany). Potable water was added to the dates paste ata ratio of 1:2.5 date paste: water, as recommended by AIHarthi [8]. The dates paste-water mixture wasmechanically mixed and heated to 70 C for a period of 2016 International Journal of Food EngineeringF. Determination of Ascorbic Acid ContentsAscorbic Acid (AA) and Dehydroascorbic Acid(DHAA) contents were determined by HPLC-UV asdescribed in González-Molina et al. [30]. The vitamin Ccontent was calculated by adding ascorbic acid anddehydroascorbic acid values, and results were expressedas mg per 100ml.10

International Journal of Food Engineering Vol. 2, No. 1, June 2016B. Chemical Composition of DatesProximate and nutritional analysis are essential forassessing health benefits of various fruits. In this study,we determined moisture, carbohydrate, fat, crude fibers,ash, protein, dry matter, and energy contents of dates.The chemical composition of the studied types of dates ispresented in Table II as mean sd. There were cultivardifferences in these parameters. Ismail et al. [31] reportedthat moisture level ranged from 20% to 22% in Khalasgrowing in UAE, while Saudi Khalas dates showed lowervalues for moisture content (15.3 to 19.8%).Thisdifference can be attributed to the amount and frequencyof irrigation as well as postharvest handling. Themoisture content was significantly different between thethree types of dates (P 0.05). The moisture content was15.3 0.1, 11.2 0.0, and 10.3 0.2g/100g for R, K, and Sdates, respectively. Dates are rich in sugar ranging from65% to 80% on dry weight basis mostly of reducingsugars (glucose and fructose). Dates carbohydratescontent is mainly reducing sugars in the form of glucose,fructose, mannose and maltose and non-reducing sugars(primarily sucrose), as well as small amounts ofpolysaccharides such as cellulose and starch [32]. Thethree types of dates were characterized by their highcarbohydrates content and a predominance of sugars(Table I). Carbohydrates content was highest in S dates(84.2 0.3g/100g), followed by K dates (82.1 0.2g/100g)and R dates (78.0 0.1g/100g); this measurement wassignificantly different among the three types of dates(P 0.05). Ali et al. [33] reported 68.53% to 75.37%range for carbohydrates in Omani dates. Similarly,Myhara et al. [34] suggested a mean of 80.6g/100gcarbohydrates content for dates. This may indicategenotypic differences between date cultivars incarbohydrates production as well as differences in theeffects of the environmental conditions that prevailduring the growing season. The amount of total sugarswere not significantly different among the three dates;total sugars were 71.1 0.40, 68.4 1.9, and67.0 1.9g/100g in K, S, and R dates, respectively.Sucrose was the predominant sugar in the S dates(54.3 1.8g/100g), which was significantly greater ascompared to that of K (0.5 0.1g/100g) and R(0.5 0.1g/100g) dates. S dates are popular due to theirhigh sucrose content, which confers a pleasant taste to thefruit [23], [35]. Fructose and glucose were predominantin K (33.6 0.2 and 37.0 0.1g/100g, respectively) and R(32.6 1.4 and 33.9 0.6g/100g, respectively) dates;between these two dates, the difference in fructosecontent was not significant, although their difference inglucose content was significant (P 0.05). The lowsucrose content observed in K and R dates may be due toenvironmental and genotypic factors that may affect boththe qualitative and quantitative composition of the sugarfraction by altering the activity of the enzymes involvedin the synthesis and breakdown processes. The S dateshad significantly lower fructose (6.3 0.0g/100g) andglucose (7.8 0.1g/100g) contents. Glucose and fructoseare important energy sources [25] and are easilydigestible and hydrolysable. Based on these facts, IsmailG. Statistical AnalysisAll parameters were determined in triplicate for eachsample. Statistical analysis was performed with SPSS forwindows (version I2). All data are expressed as mean standard deviation (mean sd). Data were analyzed withone-way analysis of variance using a statistical software(SPSS, Version 19.0; IBM Corporation, New York, NY,USA). A difference was considered significant at p 0.05.III. RESULTS AND DISCUSSIONA. Basic Physical Properties of Whole Date FruitData are shown in Table I, the mass of dates wassignificantly different (P 0.5); K dates had the greatestmass (9.1 1.2g), followed by S (8.9 0.9g), and R(6.8 0.6g). Fruit length, major diameter, pit mass and pitmass ratio were significantly different (P 0.5) betweenthe three date cultivars. Fruit length range was 27.5 2.0 36.7 2.5mm. The major diameters range was 20.7 1.0 24.0 1.3mm. The pit mass of the three types of datesranged between 0.7 0.1 - 1.0 0.1 and the pit mass ratiosrange was 0.1 0.0 - 0.2 0.0.The data collected for the basic physical properties forthe three types of dates were in agreement with otherpublished data [18]-[20].TABLE I.BASIC PHYSICAL PROPERTIES AND COLOR PARAMETERSOF THE THREE DATE FRUITS OF SUKKARI(S), KHLASS(K) ANDREZAIZ(R) AT FINAL STAGE OF MATURITY*PropertyS8.9 0.9 b30.6 1.9 bDate cultivarK9.1 1.2 a36.7 2.5 aRDate fruit mass (g)6.8 0.6 cFruit length (mm)27.5 2.0 cFruit major24.0 1.3 a21.2 2.8 b20.7 1.0 bdiameter (mm)Pit mass (g)1.0 0.1 a0.8 0.1 b0.7 0.1 cPit mass ratio0.1 0.01 a0.1 0.01 b0.1 0.01 a*Same letter in row means no significant differences at p 0.05.TABLE II. CHEMICAL COMPOSITION OF THE DATE FLESH OF THETHREE DATE FRUITS OF SUKKARI(S), KHLASS(K) AND REZAIZ(R) ATFINAL STAGE OF MATURITY*ComponentCarbohydrate (g/100g)Total sugars (g/100g)Fructose (g/100g)Glucose (g/100g)Sucrose (g/100g)Protein (g/100g)Fat (g/100g)Moisture (g/100g)Ash (g/100g)Crude Fiber (g/100g)Vitamin C (mg/100g)Energy (kcal/100g)Potassium (mg/100g)Magnesium (mg/100g)Calcium (mg/100g)Phosphorus (mg/100g)S84.2 0.3 a68.4 1.9 a6.3 0.00 b7.8 0.1 c54.3 1.8 a3.1 0.1 a0.2 0.0 a10.3 0.2 c1.8 0.1 a3.7 0.1 a1.2 0.0 c315.2 0.8 a585.0 7.1 a76.1 1.3 a64.1 1.3 a10.8 0.3 aK82.1 0.2 b71.1 0.4 a33.6 0.2 a37.0 0.1 a0.5 0.1 b2.1 0.0 c0.2 0.0 a11.2 0.0 b1.8 0.2 a2.7 0.1 b1.8 0.0 a307.6 0.5 b565.0 21.2 ab59.9 1.6 b59.7 0.6 b5.4 0.1 cR78.0 0.1 c67.0 1.9 a32.6 1.4 a33.9 0.6 b0.5 0.1 b2.6 0.0 b0.2 0.0 a15.3 0.1 a1.5 0.1 a2.5 0.1 c1.6 0.0 b294.6 0.3 c525.0 7.1 b46.4 0.4 c55.9 0.7 c6.4 0.1 bSodium (mg/100g)9.1 0.1 a11.5 2.1 a11.0 1.4 a*Data are expressed as mean SD (n 3) based on 100g date flesh.Means SD followed by the same letter, within a raw, are significantlydifferent at p 0.05 level. 2016 International Journal of Food Engineering11

International Journal of Food Engineering Vol. 2, No. 1, June 2016study conducted in UAE [31], showed similar range ofash content (1.8% to 2.34%) to that reported in this study.Potassium was the most abundant mineral in the threedates, with contents of 585.0 7.1, 565.0 21.2, and525.0 7.1mg/100g in the S, K, and R dates, respectively.Magnesium and calcium were also relatively abundantand significantly different between the three dates. In Sdates, magnesium and calcium contents were 76.1 1.3and 64.1 1.3mg/100g, respectively. In K dates,magnesium and calcium contents were 59.85 1.63 and59.70 0.57mg/100g, respectively. In R dates, magnesiumand calcium contents were 46.35 0.35 and64.05 1.34mg/100g,respectively.InSdates,phosphorous and sodium contents were 10.8 0.3 and9.1 0.1mg/100g, respectively. In R dates, phosphorousand sodium contents were 6.4 0.1 and 11.0 1.4mg/100g,respectively. In K dates, phosphorous and sodiumcontents were (5.4 0.1 and 11.5 2.1mg/100g,respectively. All minerals, except sodium, were highestin content in S dates. K dates were the second high in allmineral contents, except for phosphorus, which washigher in R dates. However, Ahmed et al. [39] reportedin their study on dates from twelve cultivars of date palm,which are widely consumed in the UAE, that dates areexceptionally rich in potassium and extremely low insodium. The differences in mineral content of dates aremainly due to soil fertility in the fields where date palms,from which the random samples were collected, aregrown. It has also been reported that the mineral contentof the dates may be influenced by environmental factors,soil characteristic and the amount of fertilizers add todate palms [10].et al. [31] suggested that the dates have an importantagro-industrial future as a potential source of refinedliquid sugar.Dates are considered as high-energy fruits due to theirhigh sugar content; these fruits are also important sourcesfor fiber and minerals [21], [23]-[25]. The energymeasured in the three types of dates was significantlydifferent (P 0.05); the highest energy value was found inthe S dates (315.2 0.8kcal/100g), followed by the K(307.6 0.5kcal/100g) and R (294.6 0.3kcal/100g) dates.Protein and crude fiber contents were significantlyhigher in the S dates (3.1 0.1 and 3.7 0.1g/100g,respectively) as compared to the K dates (2.1 0.0 and2.7 0.1g/100g, respectively) and R dates (2.6 0.0 and2.5 0.1g/100g, respectively). Our results showed asimilar trend to those found in Iranian dates [26]. Withrespect to the reported results [22], [27], [28], the studieddates are considered to have higher levels of proteins.Their differences in protein content may be due togenotypic and environmental factors. The protein contentof the tested dates was similar as those previouslyreported in other studies [31]. The results of this studyshowed that the protein content in S dates is higher thanthat of the other two types of dates. This protein contentwas also higher than that reported by Sawaya et al. [35]in regards to the dates of different cultivars in SaudiArabia. Similarly, the protein content of eight differentPakistani dates ranged from 2.0% to 2.7% [36], whichare less than the protein contents of the studied dates. Ithas been estimated elsewhere that protein content ofdates range between 1% and 3% [6]. In Deglet Nour andMedjool dates, the protein content is 2.45% and 1.8%respectively which is also less than that found in thetested dates. Our data also support a higher proteincontent in the tested dates when compared to thosementioned by Al-Shahib and Marshall [32] who reporteda range between 1% and 2.5%.Fat content was small, with insignificant differencesbetween the three tested dates. The fat contents were0.2 0.0g/100g in S, K, and R dates, respectively. AlShahib and Marshall [32] found fats content rangingfrom 0.1% to 0.2% in Saudi and UAE dates. Our resultsare in line with those of Al-Hooti et al. [10]. whorecorded similar fats content in five different UAE dates.The Deglet Nour and Medjool dates contained 0.1% to0.3% of fats [3]. Thus the differences in fat contents maybe for genotypic reasons. The tested dates containedsmall amounts of vitamin C. Vitamin C content washighest in the K dates (1.8 0.0g/100g), followed by the R(1.6 0.0g/100g) and then S (1.2 0.0g/100g) dates;significant differences were observed between the threedates types in vitamin C contents. Similar results wererecorded by Suleiman et al. [37] who assessed fivedifferent Sudanese dates.Ash contents were not significantly different betweenthe three dates. The ash contents were 1.8 0.1, 1.8 0.2,and 1.5 0.1g/100g in S, K, and R dates, respectively.Jamil et al. [38] in a study on eight different Pakistanidates, showed that the ash content ranged from 1.0% to2.5% which is in conformity to our findings. A similar 2016 International Journal of Food EngineeringC. Chemical Composition of Lemon and Dates JuicesTable III shows the results from the chemical analysisof natural S, K, and R dates juices. The analysis ofvariance showed statistically significant differences in thecharacteristics of the studied nine juices.TABLE III. PH, TOTAL TITRATABLE ACIDITY (TA) AND TOTALSOLUBLE SOLIDS (TSS) OF DIFFERENT DATES AND LEMON JUICES ANDTHEIR MIXTURES*ParametersJuicespHTitratable acidity Total Soluble Solids(%) as citric (TA)(TSS) ( Brix)100% LJ2.8 0.0c5.36 0.0a8.2 0.0b100% SJ6.1 0.0a0.1 0.0c22.2 0.0aSJ 5% LJ3.9 0.0b0.5 0.0bc22.8 0.0aSJ 10% LJ3.5 0.0b0.7 0.0b22.6 0.0a100% KJ6.3 0.0a0.1 0.0c21.5 0.0aKJ 5% LJ3.9 0.0b0.4 0.0bc22.3 0.0aKJ 10% LJ 3.5 0.0b0.7 0.0b22.5 0.0a100% RJ5.3 0.0a0.1 0.0c21.0 0.0aRJ 5% LJ3.8 0.0b0.4 0.0bc21.4 0.0aRJ 10% LJ3.4 0.0b0.8 0.0b21.7 0.0a*Data are expressed as mean SD (n 3). Means followed by the sameletter within each column are not significantly different at p 0.05 levelusing Duncan’s multiple range test.D. pH, Titratable Acidity and Total Soluble SolidsThe main characteristics of the prepared lemon, datesand mixed juices are given in Table III, Table IV, Table12

International Journal of Food Engineering Vol. 2, No. 1, June 2016IV). From the above data, significant differences amongtypes of mixed and controls juices were observed interms of these traits. Many factors, such as soil fertilityand irrigation may affect carbohydrates and solublesugars contents of dates and lemon fruits.V and Table VI. Characteristics, such as pH, totalTitratable Acidity (TA) and Total Soluble Solids (TSS)that are shown in Table III, were chosen to characterizethe overall quality of the tested juices. The data showedsignificant differences in juice quality traits of mixed andcontrol juices. The results are presented as mean standard deviation (Table III). The lowest pH (2.8 0.0)was for lemon juice, the same juice had the lowest totalsoluble solids, but the highest total acidity. The statisticalanalysis showed no significant differences in pH betweenthe mixed juices, but they all differ significantly from thecontrol juices. The pH values in the mixed juicesdecreased with the percentage of LJ added, ranging from3.4 0.0 for RJ 10% LJ to 3.9 0.0 for KJ and SJ 5% LJ(Table III).The results of TA in 100% dates juices were found tobe 0.1% and 5.36% in 100% LJ. These values were in anagreement with the known percent in dates and lemonfruits used in this study. Consequently, the acidityincrease in the mixed juices was proportional to theadded LJ.Regarding the Total Soluble Solid contents (TSS), incase of LJ100 is 8.2 rix (Table III), these were inaccordance with reported contents for lemon juices [3].The TSS contents of the mixed juices were representativeof the addition of individual components of each mixture.TSS was insignificantly different in all juices with theexception of LJ. TSS in mixed juices varied between22.8 0.0 rix in SJ 5% LJ and 21.4 0.0 Brix in RJ 5%LJ.From these data, significant differences among the 10types of fruits juices were observed in terms of the threetested quality characteristics. Of all mixed juice types, theSJ 5% LJ showed best quality characteristics in terms ofthe mentioned parameters.TABLE IV. CARBOHYDRATES AND SOLUBLE SUGARS CONTENT OFDIFFERENT DATES AND LEMON JUICES AND THEIR MIXTURES*ParametersJuices100% LJ 11.7 0.3b100% SJ 22.2 0.4aTotalSugarsFructose1.0 0.0c0.50 0.0c 0.49 0.0c 0.01 0.0cGlucoseSucrose1.9 0.0b 2.1 0.0b 15.2 0.6aSJ 5%23.5 0.3a 19.5 0.3a 1.9 0.1b 2.3 0.3b 15.3 0.1aLJSJ 10%23.4 0.1a 20.2 0.1a 1.9 0.1b 2.4 0.2b 15.9 0.3aLJ100%23.7 0.4a 18.1 0.0a 8.7 0.3a 9.3 0.6a 0.1 0.0bKJKJ 5%22.3 0.3a 18.9 0.8ab 9.1 0.2a 9.5 0.6a 0.3 0.0bLJKJ 10%21.3 0.6a 19.1 0.9ab 9.3 0.2a 9.6 0.2a 0.2 0.0bLJ100%21.3 0.5a 16.8 0.3ab 8.4 0.2a 8.3 0.5a 0.1 0.0bRJRJ 5%20.9 0.2a 17.9 0.4b 8.9 0.1a 8.9 0.3a 0.1 0.0bLJRJ 10%20.6 0.5a 18.6 0.6b 9.2 0.0a 9.2 0.3a 0.2 0.0bLJAll values are in g/100g.*Data are expressed as mean SD (n 3). Means followed by the sameletter within each column are not significantly different at p 0.05 levelusing Duncan’s multiple range test19.2 0.7aF. Protein, Ascorbic Acid, Moisture and AshThe protein contents of the mixed and the controljuices differed significantly, but those of lemon juicewere markedly higher (0.8 0.1) (Table V). The KJ mixedand control juices were generally low, varying between0.52 0.0g/100g in SJ 10% LJ and 0.20 0.0g/100g in100% KJ. The differences in protein content between thetested juices may be due to analytical, environmental orgenotypic differences.The ascorbic acid (Vitamin C) contents of the testedjuices (Table V) differed significantly, however, those oflemon juice were significantly high (23.9 0.2mg/100g).Vitamin C in the mixed juices varied in accordance to theadd percentages of LJ to dates juice (Table V). Thehighest Vitamin C content was recorded in SJ 10% LJ(5.7 0.9mg 100g), followed by KJ 10% LJ(5.4 0.6mg/100g), no significant differences werenoticed in Vitamin C content between the mixed juices(Table V). In the present study, we found that vitaminproduction was cultivar specific, since the genotype ofthe date cultivar has direct influence on the metabolicpathways of the plant. Also, the ascorbic acid productionmay be greatly influenced by environmental conditions.Results of the moisture content of the tested juices arepresented in Table V. Moisture contents of the differentjuices with the exception of moisture content for lemonjuice were not significantly different. The moisturecontents of the tested juices ranged between 74.8 0.5%in 100% SJ and 89.7 0.2% in 100% LJ (Table V). Thevariations in moisture content in fruits have beenE. Carbohydrates and Soluble SugarsThe carbohydrates and soluble sugar of the control andmixed juices are presented in Table IV. The resultsindicated that the carbohydrates contents varied between23.7 0.4g/100g, for 100% KJ, and 20.6 0.5g/100g, forRJ 10% LJ. The lemon had the lowest amount ofcarbohydrates (11.7 0.3g/100g). There were insignificantdifferences (P 0.05) in the carbohydrates contents amongthe mixed juices, but they were all significantly differentwhen compared to LJ.The total sugars contents in the tested juices showedconsiderablevariations(TableIV),reaching20.2 0.2g/100g in SJ 10% LJ. This was relatively higherthan its counterparts KJ 10% LJ (19.1 0.9g/100g) andRJ 10% LJ (18.6 0.6g/100g). The sucrose content wassignificantly higher in S J 10% LJ (15.9 0.3g/100g) ascompared to its fructose (1.9 0.1g/100g) and glucose(2.4 0.2g/100g) contents (Table IV). The latter sugarswere significantly higher in KJ 10% LJ (9.3 0.2,9.6 0.2, and 0.2 0.0g/100g for fructose, glucose andsucrose, respectively), and RJ 10% LJ (9.2 0.0, 9.2 0.3,and 0.2 0.0g/100g for fructose, glucose and sucrose,respectively) 11.75), however, the lemon juice had thelowest (0.50 0.0, 0.49 0.0, and 0.1 0.0g/100g forfructose, glucose and sucrose, respectively) values (Table 2016 International Journal of Food EngineeringCarbohydrate13

International Journal of Food Engineering Vol. 2, No. 1, June 2016attributed to many factors e.g. genotypic differences,climatic conditions, cultural practices and postharvesthandling measures [40].Insignificant differences were observed between thetested juices for ash content (Table V). The ash content inthe tested juices varied between 0.3 0.0g/100g in 100%LJ and 0.4 0.0g/100g in all other juices (Table V).100% KJ (Table VI). The P content varied between13.6 0.0 in RJ 10% LJ to 5.6 0.0mg/100g in 100% KJ(Table VI). K content varied between 120.7 0.4mg/100gin SJ 10% LJ and 101.4 0.1mg/g in 100% KJ (Table VI).Na content varied between 5.2 0.1 for SJ 10% LJ and2.3 0.00mg/100g for 100% KJ (Table VI). These resultsreflect the low mineral content of KJ which may be dueto the low soil fertility in the fields where Khlass datepalms were planted.TABLE V. PROTEIN, ASCORBIC ACID, MOISTURE AND ASHCONTENTS OF DIFFERENT DATES AND LEMON JUICES AND THEIRMIXTURES*JuicesProtein(g/100 g)0.80 0.1a0.40 0.0b0.50 0.0bParametersVitamin Cmoisture(mg/100g)%23.9 0.2a89.7 0.2a0.4 0.0c74.8 0.5b4.06 0.3b75.8 0.2bIV. CONCLUSIONSAsh (g/100g)0.3 0.0a0.4 0.0a0.4 0.0aDates, one of the most nutritious fruits in Saudiagriculture, is an ideal raw material for different valueadded products. There is a growing interest in thekingdom for conducting research and developmentactivities to identify new dates products for commercialutilization. The physical measurement of dates from thethree cultivars grown in Saudi Arabia revealed that fruitsdiffered in the physical measurement

D. Chemical Composition of Dates Flesh and Juice Basic physical properties of dates from the three cultivars, Sukkari(S), Khlass(K), and Rezaiz(R), were experimentally determined at room temperature (23 C). The standard AOAC methods [29] were used to analyze all dates flesh and juice samples.

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