PaPer Ital. J. Food Sci., vol. 27 - 2015 397 - Keywords: date fibre, ice cream, elemental composition, nutraceutical ingredient - Mineral Contents and PhysiCal, CheMiCal, sensory ProPerties of iCe CreaM enriChed with date fibre filiz yangilar Erzincan University School of Health Department of Nutrition and Dietetics, 24100, Erzincan, Turkey Tel. +90 446 2266669, Fax: +90 446 2265862 email: f_yangilar@hotmail.com AbstrAct Date samples of Amber cultivar straining from Medina region (saudi Arabia) were analysed for their chemical compositions and physicochemical properties of date fibre in the present study. Fi- bre rich date pieces were found to contain 80.2 g/100 g total dietary fibre, 16.32 g water/g sample water-holding capacity while 9.50 g oil/g sample oil-holding capacity. It can be stated from these results that fibre content of date is a valuable dietary fibre source and used in food production as an ingredient. Effects of the addition of date fibres at different concentrations (1, 2, 3 and 4%) were investigated on the physical, chemical, sensory properties and mineral content of ice cream in the present study. It was found that elemental composition of ice cream samples was affected significantly by the addition of date fibre concentrations (p<0.05) and the rates of K, Mg and Zn especially increased in the samples depending on the content of date fibre while the content of ca and P decreased. It was determined from the sensory results that ice cream sample containing date fibre in the rate of 1 and 2% received the highest score from panellists. 398 Ital. J. Food Sci., vol. 27 - 2015 IntroDuctIon Dietary fibre as a class of compounds includes a mixture of plant carbohydrate polymers, both oligosaccharides and polysaccharides (cellulose, hemicelluloses, pectic substances, gums, resis- tant starch, inulin) that may be associated with lignin and other non-carbohydrate components (polyphenols, waxes, saponins, cutin, phytates, resistant protein; ELLEucH et al., 2011). over the last decades, knowledge on dietary fibre has increased considerably, both in the physiolog- ical and analytical areas. Health benefits of di- etary fibre are associated with bowel function, reduced risk of coronary heart diseases, type 2 diabetes and improved weight maintenance (AGostonI et al., 2010; HAunEr et al., 2012; WEstEnbrInK et al., 2012). In addition, dietary fibre can provide a multitude of functional prop- erties when they are incorporated in food sys- tems. several advantages of using fruit fibres in ice cream production are improvement in body due to the fibrous framework and melting prop- erties, reduction of cold impression, reduction of recrystallization causing prolonged shelf-life, and enhancing mixed viscosities allowing freez- ing at higher overrun, causing no negative ef- fect on the ice crystal sizes, and leading to a more homogenous air-bubble formation (Anon- YMous, 2000; DErVIsoGLu and YAZIcI, 2006). thus, fibre addition contributes to the modifi- cation and improvement of the texture, sensory characteristics and shelf-life of food due to their water binding capacity, gel-forming ability, fat mimetic, anti-sticking, anti-clumping, texturis- ing and thickening effects (DELLo stAFFoLo et al., 2004; GELrotH and rAnHotrA, 2001; tHE- bAuDIn et al., 1997, chap. 23; souKouLIs et al., 2009). there is little data dealing with the study of the functionality of dietary fibre in ice creams (souKouLIs et al., 2009). Date (Phoe- nix dactylifera L.) provides a good source of di- etary fibre content, is also considered to be a commercially important agricultural commodi- ty as well as vital element of the daily diet and a nutritious food in the Arabian world (KHAn et al., 2008; AL-FArsI and LEE, 2008) general- ly being consumed fresh or processed into var- ious products (sInGH et al., 2013). Annual pro- duction rate of date all across the world in 2010 was about 7.91 million tons, which increased in the rate of 6.6% in when compared to 2009 (FAo, 2011; AHMED et al., 2013). Different vari- eties of date vary in their chemical composition especially in sugars and dietary fibre (MustAFA et al., 1986; AHMED et al., 1995; rAHMAn and AL-FArsI, 2005; sInGH et al., 2013). the impor- tance of date in human nutrition comes from its rich composition of carbohydrates (70-80%), salts and minerals, dietary fibres, vitamins, fat- ty acids, antioxidants, amino acids and protein (EL-bELtAGY et al., 2009; AL-sHAHIb and MAr- sHALL, 2003; EL-nAGGA and AbD EL–tAWAb, 2012; AL-FArsI et al., 2005, 2007; bIGLArI et al., 2008; HonG et al., 2006; MAnsourI et al., 2005; VAYALIL, 2002; KcHAou et al., 2013). In fact, date fruit has been used in traditional medicine as immune system stimulator (PurI et al., 2000), and as treatment for various infectious diseas- es (DuKE, 1992; MArtÍn-sÁncHEZ et al., 2013). However, such a valuable nutrient is gener- ally discarded or used in animal feeding. A se- rious economic loss can be experienced unless such a useful fruit and its products are used in human diet and food since it is rich in bio- active compounds, which can be extracted and used as value added materials. Development of new food products using date flesh is the topic of very limited number of studies. the objective of the present study is to characterize and eval- uate the functional properties of the us date fi- bre (DF) taking into account the quality and nu- tritional content of ice cream. MAtErIALs AnD MEtHoDs Materials cows’ milk and cream were obtained by the research and Application Farm of Atatürk university. Amber dates were purchased from the palm garden in Medina city of saudi Ara- bia. sugar, salep and emulsifier (mono- and di- glycerides) were obtained from local markets. skim milk powder was supplied by Pınar Dairy Products co. (turkey). Preparation of date flour Date fibre concentrates were extracted from the Medina cultivar ‘Amber’ as described pre- viously (ELLEucH et al., 2008). DF from whole fruits were extracted in boiling water for 15 min, using a magnetic stirrer. After solubilisation of the sugars (sucrose, glucose and fructose), date fibres and pits were recovered through filtration using a 0.2 mm sieve. the pits were then re- moved. the fibres were concentrated by succes- sive rinsing (water at 40°c) and filtration until the residue was free of sugar as described. the residues obtained were pressed dried, in oven at 65°c for 24 h and milled in a Mill Laboratory at 2890 rpm, then at 5000 rpm until they could pass through a 0.2 mm sieve to recover the date fibre concentrate, and stored at -18°c for sub- sequent physicochemical analyses and incorpo- ration studies. Chemical composition Moisture content was determined according to the Association of official Analytical chemists (AoAc, 1997) method. Ash was analysed by com- busting the sample in a muffle furnace at 550°c for 4 h. the residue was dissolved in Hno 3 and Ital. J. Food Sci., vol. 27 - 2015 399 the mineral constituents (ca, K, na, Mg, P and Fe) were determined using an inductively cou- ple plasma spectrophotometer (Perkin-Elmer, optima 2100 DV, IcP/oEs, shelton, ct, usA). the bligh and Dyer method (HAnson and oL- LEY, 1963) was used to determine the lipid con- tent. Protein content was determined by micro kjeldahl method (AoAc, 1990) and expressed as: % n 2 x6,23. total sugars were extracted through ethanol (80%) (nInIo et al., 2003). After centrif- ugation, the supernatant was collected and the total sugar content was analysed using phenol/ sulphuric acid reagent (DuboIs et al., 1956). the total phenolic content was analysed accord- ing to the Folin-ciocalteu method developed by AL-FArsI et al. (2005). the extract (200 μL) was mixed with 1.5 mL of Folin-ciocalteu reagent (previously diluted 10-fold with distilled water) for 5 min at room temperature. 1.5 mL of aque- ous sodium bicarbonate (60 g/L) was added and the mixture was vortexed and allowed to stand at room temperature. After 90 min, the absorbance was measured at 725 nm. the total phenol con- centration was expressed as the mean ± sD as mg of gallic acid equivalent (mg GAE) per 100 g of fresh weight of date for two replicates. AoAc enzymatic-gravimetric official method (991.43; AoAc, 1995) was used to determine dietary fi- bres while dry matter content, fat, ash, acidity (ºsH) and pH of ice cream samples were deter- mined as in DEMIrcI and GunDuZ (1994). Min- eral contents (ca, K, na, P, s, Mg, Fe, Mn, Zn, ni) of ice cream samples were determined using an Inductively couple plasma spectrophotome- ter (Perkin-Elmer, optima 2100 DV, IcP/oEs, shelton, ct, usA) and following the method de- scribed by GuLEr (2007). samples were decom- posed in a microwave oven (berghof speed wave MWs-2, Eningen, Germany). For this purpose, about 0.5 g ice cream sample was weighed into the digestion vessels, added concentrated nitric acid (10 mL) and digestion process was realized over each sample at 210°c and under 176 psi pressure for 10 min. After cooling, the carousels were removed from the oven, 30% hydrogen per- oxide (2 mL) was added to samples and then sec- ond digestion was applied at 195°c and under 95 psi pressure for 5 min. the vessels were im- mediately closed after the addition of oxidants. At the end of the digestion process, the samples were diluted in with distilled water to an appro- priate concentration and filtered through What- man no. 42 filter paper. All diluted digests were eventually analysed using an Inductively couple plasma spectrophotometer (IcP-oEs). Water and oil holding capacities, and pH of fibre Water and oil holding capacities (WHc and oHc) of the fibres were determined according to the methods of MAc-connELL et al. (1997) and cAPrEZ et al. (1986), respectively. WHc and oHc values represented the amount of water and oil absorbed per gram of sample, respectively. pH of DF was measured using a pH meter (WtW 340- 1) and following the method described by sun- tHArALInGAM and rAVInDrAn (1993). Ice cream manufacture the ice cream samples were prepared in the Pilot Plant of Food Engineering Department, Ag- riculture Faculty, Atatürk university. Initially, the fat ratio of cows’ milk was adjusted to 6% by adding cream. then, the milk was divided into five equal parts of 2 kg. For each mix, skim milk powder (125 g), sugar (405 g), salep (stabilizer) (16.2 g), emulsifier (mono- and di-glycerides) (6.75 g) were added to each mix. then prepared date fibres were added at four different concen- trations: 1, 2, 3 and 4% to mixture weight. the mixes were pasteurized at 85°c for 25 min and stored at 4°c for 24 h. then, they were iced in ice cream machinery (-5°c; ugur cooling Ma- chineries co., nazilli, turkey) and hardened at -22°c for 24 h and stored at -18°c and used for physical, chemical, mineral and sensory analyses. Ice cream samples were produced in duplicate. Ice cream analysis Physical measurements. overrun was deter- mined using a standard 100 mL cup, according to the equation [(volume of ice cream)-(volume of mix)/volume of mix×100] given by JIMEnEZ-FLo- rEZ et al. (1993). First dripping and complete melting times were measured according to Gu- VEn and KArAcA (2002) 25 g of tempered sam- ples were left to melt (at room temperature, 20ºc) on a 0.2 cm wire mesh screen above a beaker. First dripping and complete melting times of the samples were accepted to be seconds. the vis- cosities of the ice cream mixes were determined at 4ºc using a digital brookfield Viscometer, Model DV-II (brookfield Engineering Laborato- ries, stoughton, MA, usA). before measuring the viscosity, the samples were stirred gently to re- move the air from the mixes (AKIn et al., 2007). the color analyses (L*, a* and b* values) of the ice cream mix were carried out using in Minol- ta colorimeter (chroma Meter, cr-200, osaka, Japan; AnonYMous, 1979). the colorimeter was calibrated using a white reference plate before measurements. Light source for the colorime- ter was standard daylight (c) and the standard observer was 2°. Sensory evaluation Eight professional panellists from the Food Engineering Department of Atatürk university, Erzurum, turkey, participated in the study to determine some properties using a score test for flavour, body and texture, color and appearance, 400 Ital. J. Food Sci., vol. 27 - 2015 resistance to melting and general acceptability. Hardened ice cream samples were tested at a serving temperature of -10ºc and scored their sensory characteristics in a scale ranging from 1 (poor) to 9 (excellent). Warm water and bread were also provided to the panellists to cleanse their palates between samples. All panellists were non-smokers, had prior testing experience with a variety of dairy products including milk, cheese and ice cream and had previously used flavour profile procedures adapted from roLAnD et al. (1999). Statistical analysis All statistical analysis was performed using sAs for windows (sAs, 1998). Analysis of vari- ance was performed using the routine Proc Ano- VA. significant treatment was separated using Duncan’s Multiple range test (DuZGunEs et al., 1987). rEsuLts AnD DIscussIon Physical and chemical characteristics of date fibre Dry matter, fat, acidity (osH) and pH values of milk, skim milk powder and cream used in the production of the ice cream are given in table 1. Date and date fibre were analyzed for mois- ture, ash, fat, total sugars, color, total phenol- ic content, WHc and oHc (table 2). Date fibres are rich in protein (9.01 g/100 g). Earlier, EL- LEucH et al. (2008) reported 9 g/100 g protein contents for tunisian dates and similar to the present work. Presence of high protein content in fruit fibres (11.6-14.4 g/100 g) is reported in the literature (brAVo and sAurA-cALIXto, 1998; sAurA-cALIXto, 1998). In the present study, cal- cium, sodium, potassium and magnesium con- tents of date fibre were measured to be 1925, 56.5, 981 and 1807 mg/kg, respectively. AHMED et al. (2013) reported that the sodium content was significantly lower than other minerals (55- 86 mg/kg); however, the fibres were rich in po- tassium. the barhee cultivar possessed excep- tionally higher amount of potassium (2600 mg/ kg), and the maximum sodium was found in ow- adi cultivar. these results are significantly differ- ent from the reported values for date flesh (EL- LEucH et al., 2008). the variation could origi- nate from the cultivar, and agro-climatic as well as environmental conditions. Date contains high proportions of total die- tary fibre (80.2 g/100g) similarly to those re- ported in Deglet-nour and Allig (two varieties of date) between 88 and 92%, respectively (EL- LEucH et al., 2008). In addition, the contents of dietary fibre in dried apricots, prunes, figs, and raisins were 7.7, 8.0, 12.2, and 5.1 g/100 g, re- spectively (cAMIrE and ouGHErtY, 2003; MAr- LEtt et al., 1994; VInson, 1999). thus, dates and their by-products serve as good sources of fibre compared with syrups and other fresh and most dried fruits. In addition, these DF con- tents are close to levels measured for DF prep- arations from apple (Liberty cultivars) (89.8%), but notably higher than those of other fruit DF concentrates reported for grapefruit, lemon, or- ange, apple and mango (28-78.2%) (FIGuEroLA et al., 2005; VErGArA-VALEncIA et al., 2007), table 1 - the gross chemical, physical properties and min- eral contents of raw milk, skim milk, cream. Analysis Milk Skim milk powder Cream Dry matter (%) 11.37 95.17 63.76 Fat (%) 3.5 1.00 65.00 Ash (%) 0.67 - - Acidity (oSH) 5.81 - 13.98 pH 6.40 - 4.95 Minerals (mg kg-1) Ca 1224.00 K 1397.00 Mg 91.67 P 869.54 Na 327.90 Fe 13.56 - Not determined. table 2 - chemical and physical properties of date fibre and date. Chemical analysis Date Date fibre Moisture (g/100 g) 13.61±0.11 3.87±0.13 Ash (g/100 g) 1.79±0.07 2.06±0.04 pH 6.00±0.21 5.71±0.02 Protein (g/100 g) 1.23±0.16 9.01±0.75 Fat (g/100 g) 3.41±0.03 0.98±1.21 Total sugars 78.20 0 Total phenolic contentc 186±2.30 0.73±0.01 Total dietary fibre (g/100 g) 8.75±0.96 80.2±1.06 Minerals (mg kg-1) Ca 23.40±0.51 1925±1.84 K 428±0.14 981±2.04 Mg 84.51±0.22 1807±0.82 P 90.19±1.36 1325±0.51 Na 17.65±0.12 56.5±0.05 Fe 2.03±0.07 24.82±1.36 Physical Analysis L* 23.8±0.04 61.08±0.05 a* 11.0±0.03 6.35±0.01 b* 8.9±0.07 14.72±0.01 WHCa - 16.32±0.47 OHCb - 9.50±0.23 aWater holding capacity (g water/g, sample); bOil holding capacity (g oil/g, sample); cg/100 g of DF concentrates; L* = lightness; a* = redness (+) and blueness (–); b* = yellowness. Ital. J. Food Sci., vol. 27 - 2015 401 grape skins (54.1–64.6%) (brAVo and sAurA-cA- LIXto, 1998; sAurA-cALIXto, 1998), citrus peel (57%; cHAu and HuAnG, 2003), or fibre from lime peels (66.7% and 70.4%; ubAnDo et al., 2005) and mango peel (71%; LArrAurI et al., 1996). WHc was found to be 16.32 (g water/g, sam- ple) in date fibre in the present study. WHc in of date fibres was reported to be significantly higher than those of fruit and vegetable fibres (FEMEnIA et al., 1997; GAn and LAtIFF, 2011; LoPEZ et al., 1996; VErGArA-VALEncIA et al., 2007; AHMED et al., 2013), but similar to those found in date (15.5 g/g, dry matter) by ELLEucH et al. (2008). oHc is another functional proper- ty of some ingredients used in formulated food. In general, date fibre showed significantly high- er oHc (9.5 g oil/g, sample) when compared to other fruit and vegetable derived fibres (GAn and LAtIFF, 2011; VErGArA-VALEncIA et al., 2007). the highest oHc was observed for Allig culti- var (9.9 g oil/g sample) followed by ELLEucH et al. (2008). Higher oHc of date fibre indicated that it could be used as an ingredient to stabi- lize foods with a high percentage of fat (ELLEucH et al., 2008; AHMED et al., 2013). the mean L*, a* and b* values were found to be 61.08, 6.35 and 14.72, respectively. this could be due, on the one hand, to the wash operations during the extraction and concentration of DF and, on the other hand, to the solubility of pigments re- sponsible for the dark units of color. ELLEucH et al. (2008) reported that L*, a* and b* values were 61.92, 7.11 and 14.85, respectively for Al- lig, which are convenient with the present study. GoÑI et al. (2009) informed that PP associated with polysaccharides and proteins in cell walls are significant constituents of date fibre. ta- ble 2 shows date fibre polyphenol (PP) contents (0.73 g/100 g). Physical and chemical characteristics of ice cream samples the results of some physical, chemical anal- yses and mineral contents of ice cream sam- ples are given in tables 3 and 4. the dry-mat- ter content of control sample was lower than other samples at statistically significant levels (p<0.05). the dry matter rates of ice cream in- creased with the addition of DF concentration. the highest fat and acidity ratios were found to be in control sample (4.63%). pH values of ice table 3 - some chemical and physical properties of ice cream samples with date fibre. Analysis C DF1 DF2 DF3 DF4 Moisture (%) 33.15±0.02a 33.32±0.29b 33.49±0.10a 33.63±0.36b 34.05±0.01c Ash (%) 0.89±0.01a 0.92±0.01ab 0.95±0.01b 1.06 ±0.02c 1.10±0.01c Fat (%) 4.63±1.41d 4.17±0.14c 4.15±0.03c 3.91±0.01b 3.86±0.02a Acidity(oSH) 8.99±0.00e 6.23±0.02a 6.38±0.01b 6.54±0.01c 6.73±0.02d pH 6.20±0.02e 5.62±0.02d 5.56±0.01c 5.23±0.03b 5.09±0.01a L* 83.33±0.01d 82.26±0.04d 80.27±0.03c 77.64±0.91b 75.45±0.07a a* 1.62±0.05a 2.54±0.04b 2.73±0.01c 3.21±0.04d 3.90±0.01e b* 9.15±0.02a 9.20±0.01a 11.60±0.14b 12.40±0.01c 12.50±0.02c Overrun (%) 40.51±0.00e 39.32±0.21d 37.20±0.01c 32.24±0.19b 29.87±0.06a Complete melting time (s) 0.43±0.02b 0.50±0.00c 0.46±0.02b 0.35±0.01a 0.38±0.00a Mean values followed by different letters in the same row are significantly different (p<0.05). C: Control (without date fibre); DF1: ice cream with made date fibre 1% (w/w); DF2: ice cream with date fibre 2% (w/w); DF3: ice cream with date fibre 3% (w/w); DF4: ice cream with date fibre 4% (w/w). table 4 - Elemental composition (mg kg-1) of the ash in ice cream with date fibre. Concentrations of minerals C DF1 DF2 DF3 DF4 Ca 1844.36±12.72e 1623.25±2.82d 1547±2.12c 1481.40±2.12a 1514.06±7.77b K 1669.56±21.20a 1913.06±4.15b 1939.18±1.33bc 2043.46±80.63cd 2135.46±49.95d Na 537.68±6.37b 572±0.04c 690±0.70d 528.5±0.70a 573±0.01c P 1100.86±0.01c 1257.05±4.24d 1019±2.12b 1100±0.71c 1006±2.82a S 875.24±1.41a 938.50±17.67b 980±0.70c 1015±7.07d 1103±2.12e Mg 159.31±1.39a 161.32±1.15a 164.78±0.72b 171.06±0.12c 183.33±1.59d Fe 10.82±0.24a 11.17±0.05b 14.73±0.02c 21.02±0.01d 29.65±0.22e Mn 0.32±0.01b 0.35±0.07c 0.26±0.02a 0.30±0.01b 0.40±0.01d Zn 57.84±0.86a 70.82±0.95b 84.03±0.89c 91.13±1.36d 94.56±3.93d Ni 0.97±0.06a 1.20±0.14b 1.14±0.01ab 1.70±0.01c 1.61±0.01c Mean values followed by different letters in the same row are significantly different (p<0.05). C: Control (without date fibre); DF1: ice cream with made date fibre 1% (w/w); DF2: ice cream with date fibre 2% (w/w); DF3: ice cream with date fibre 3% (w/w); DF4: ice. 402 Ital. J. Food Sci., vol. 27 - 2015 cream samples were not statistically different maybe due to pH of date (6.00). Viscosity is one of the most important proper- ties of an ice-cream mixture since it can result in a desirable body and texture in ice creams. therefore, the measurement of viscosity is im- portant to know the effect of DF on the charac- teristics of ice-cream mixtures. It could be seen in the present study that the addition of DF sig- nificantly (p<0.05) affected the viscosity behav- iour of ice cream samples (Fig. 1). Viscosity of ice-cream samples increased significantly by adding DF (3 and 4%). As shown in Fig. 1, the lowest and highest viscosity rates value were ob- tained in DF1 sample the sample with 4% DF. the control sample had an average of 5175 vis- cosity. similar results were reported in grape wine lees added in ice cream by HWAnG et al. (2009), in frozen yogurt by GuVEn and KArAcA (2002), in cape gooseberry (Physalis peruviana L.) added in ice cream by ErKAYA et al. (2012) and the citrus fibre added in ice cream mixes by DErVIsoGLu and YAZIcI (2006). Ice cream color was affected by the addition of DF. the date fibre had a brownish color. Ice cream fortified with date fibre had significant- ly higher a* and b* values and lower L* values compared to the control sample. Lightness (L*) values of ice cream samples were closer to each of dietary fibre but with DF1 and DF2 samples, it was found to be significantly higher than the Fig. 1 - the obtain of date fibre and production of ice cream. other samples (table 3). All samples had neg- ative a* values and DF3 and DF4 samples had close but significantly higher values than other samples. Increase in the concentration of date fibre contributed to the color values of the sam- ples (p<0.05). the addition of date fibre increased the b* values of all samples. the lowest b* val- ue was obtained in DF1 samples while the high- est b* was obtained in the DF4 samples. DErVI- soGLu and YAZIcI (2006) reported that the ad- dition of citrus fibre increased the color prop- erties similarly to the results of present study. overrun and melting time are associated with the amount of air incorporated during the man- ufacturing process. these features can define the structure of the end final product since the presence of air gives the ice cream an agreeable light texture and influences the physical proper- ties of melting and hardness of the end product (soFJAn and HArtEL, 2004; cruZ et al., 2009; DAGDEMIr, 2011). All ice cream samples had normally lower overrun values (29.87-40.51%) than those reported in literature (80-120%). Al- though the rate of DF lowered the overrun values of the ice-cream samples, control samples had higher overrun values than the DF added sam- ples (table 3). since the viscosity of ice cream increased in DF added samples, it was possible that less air was incorporated in the ice cream mix with DF during batch freezing, which re- sulted in lower overrun than for control (with- Ital. J. Food Sci., vol. 27 - 2015 403 out DF). the decrease of overrun values for ice creams with DF was in agreement with the re- sults indicated in literature (DErVIsoGLu et al., 2005; tEMIZ and YEsILsu, 2010). EL-sAMAHY et al. (2009) reported that the decrement of over- run in ice cream containing concentrated cac- tus pear pulp might be attributed to increment of mix’s viscosity that extremely affects whip- ping rate of mixes. HWAnG et al. (2009) reported that the overrun values of ice-cream samples de- creased significantly when grape wine lees was added. It was found by sun-WAtErHousE et al. (2013) that overrun rate of ice – cream contain- ing green kiwi fruit was 90.5% and higher than that found in the present study. However, similar results with the present study were found with cape gooseberry (Physalis peruviana L.) added in ice cream by ErKAYA et al. (2012). As can be seen in table 3, the complete melt- ing times of the ice cream samples were signif- icantly longer for DF4 samples (0.50 g min-1) and the period got longer as the fibre content increased. this is due possibly to some com- pounds existent in DF4, which have the ability of water absorption. AKIn et al. (2007) reported that the decrease in melting rate of ice cream with inulin might originate from its ability to reduce the free movement of water molecules. DF (3 and 4%) concentration affected the first dripping times positively (Fig. 2). results of the present study indicated that the first dripping times were prolonged as the fibre contents in- creased in the ice cream samples (p<0.05). It was found by DErVIsoGLu and YAZIcI (2006) that citrus fibre samples extended dripping times. these findings were similar to those in the pre- sent study. statistically significant differences (p<0.05) were found in terms of major element contents such as ca, K, Mg and s between the samples except for Mn concentration in all ice cream samples. Dairy products are known to be excellent sources of ca, P and Mg and supply dietary fibre a significant amount of calcimine, a bioavailable form (McKInLEY, 2005). Addition of date fibre lowered ca content of the samples in the present study (table 4). the highest ca was found to be 1844.36 mg/kg in control sam- ples. Mg and s values of ice cream samples in- creased with the addition of date fibre (p<0.05). Increasing K in human diet may provide protec- tion from hypertension in people who are sen- sitive to high levels of na. the highest rate of s and na was fibre detected in the samples with 4% and 2% DF to be 1103 and 690 mg/kg, re- spectively, while the lowest rates were 875.24 in control and 528.5 mg/kg with 3% DF, respec- tively. Elements like Fe, Zn and Mn are classi- fied as micro-nutrients. the addition of DF sig- nificantly increased Fe, Zn and Mn contents of the ice-cream samples (p<0.05). similar results were reported by ErKAYA et al. (2012) in cape gooseberry (Physalis peruviana L.) added ice cream samples. It can be suggested by consid- ering such a result that date fibre may be a good source to enhance dairy products such as ice- cream, which is poor in minor elements like Fe and Zn. Wu et al. (2005) reported that Zn acts as a non-enzymatic antioxidant, so that its con- sumption helps to prevent oxidative damage of the cell. the ice cream sample with 4% DF had the highest Zn content (94.56 mg/kg). Sensory evaluations results of the sensory evaluation of the ice cream samples on a scale from 1 (poor) to 9 (ex- cellent) are shown in a radar plot in Fig. 3. For- tifying ice cream with DF had a significant effect on all sensory properties except sweetness. All the fibre-enriched samples received lower scores for total evaluation in terms of sensory charac- teristics (p<0.05). Ice cream enriched with up to Fig. 2 - Viscosity values of ice cream containing date fibre and control. 404 Ital. J. Food Sci., vol. 27 - 2015 Fig. 3 - Effect of the addition of DF on the sensory profile of ice cream. c: control; DF1: 1% (w/w) date fibre added; DF2: 2% (w/w) date fibre added; DF3: 3%(w/w) date fibre added; DF4: 4%(w/w) date fibre added. 1 and 2% DF had similar mouth feeling, showed resistant to melting and gave general accepta- bility ratings as control sample. 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