Effect of Addition Some Hydrocolloids and Sweeteners on Flow Behavior and Sensory Properties of Papaya-Apricot Nectar Blends

Food Processing & Technology Sharoba et al., J Food Process Technol 2012, 3:8 http://dx.doi.org/10.4172/2157-7110.1000170 Research Article Open Access Effect of Addition Some Hydrocolloids and Sweeteners on Flow Behavior and Sensory Properties of Papaya-Apricot Nectar Blends Sharoba AM*, El-Desouky AI and Mahmoud MH Food Science Department, Moshtohor Faculty of Agriculture, Benha University, Egypt Abstract In this study, rheological properties of several food hydrocolloids (guar gum, xanthan gum and arabic gum) and sweeteners (aspartame and stevioside) were evaluated using a rotational viscometer at concentrations of (0.5% and 1.2g/L for hydrocolloids and sweeteners, respectively), Hydrocolloids and sweeteners concentrations were selected depending on preliminary sensory evaluation. The rheological properties for nectar samples were measured at four temperatures (5, 25, 50 and 75°C). The low behavior of the nectars was characterized as non-Newtonian (pseudoplastic with yield stress). The pseudoplasticity increased due to hydrocolloids addition, while it decreased due to sweeteners addition. Herschel-Bulkley and Bingham rheological models were used to describe the low behavior of papaya–apricot nectars samples. Addition of aspartame and stevioside reduced the viscosity of nectar samples compared to control nectar samples. Nectar sample contains hydrocolloids had a higher and best sensory and rheological characteristic. Papaya-apricot nectar containing guar gum, xanthan gum or arabic gum had high score in overall all acceptability. Keywords: Hydrocolloids, Sweeteners, Papaya-Apricot nectar, Flow behavior, Rheological characteristics, Activation energy for low, Sensory properties Nomenclature: Symbol ATH B1 to B12 Ea HB K n R r r2 PAN LSD S.E. T t τ τ0 γ η η∞ Term hixotropy Blend nectar numbers Activation energy for low Herschel-Bulkley Model Consistency index Flow behaviour index Gas constant Correlation coeicients Determination coeicient Papaya-apricot nectar Least signiicant diference Standard error Temperature Temperature Shear stress Yield stress Shear rate Viscosity Constant in eqn (3) Unit or deinition Pa/s KJ/mol Pa.sn Dimensionless 8.314 kJ/kg mol. K K °C Pa Pa s-1 Pa.s Pa.s Introduction Papaya ranks highest per serving among fruit for carotenoids, potassium, iber, and ascorbic acid content [1,2]. Papaya contains 108 mg ascorbic acid per 100 g of fresh fruit, which is higher than oranges 67 mg/100 g [3]. he papaya industry capacity is underutilized. First, fresh whole papaya fruit does not transport well; bruising due to a sot skin, a short shelf life. Fruit is oten sot, wrinkled and/or bruised, signiicantly decreasing consumer acceptance in an environment where unblemished J Food Process Technol ISSN:2157-7110 JFPT, an open access journal fruit is expected. Second, a processed papaya product that maintains its fresh lavor does not currently exist. Research on processing of papaya fruit has resulted in a sweet (non-bitter), stable product; traditional pasteurization treatment leads to cooked lavor development [4]. Other heat processed fruits, including apples, oranges and tomatoes, do not sufer such an extreme alteration from their fresh fruit lavor ater processing. his has led to papaya products that are mixed with other fruits to dilute or mask the of-lavors [5]. In order to improve the cloudy stability of juices for prolonged periods, hydrocolloids have been added [6,7]. Gum arabic is the dried gummy exudate from the stems and branches of Acacia Senegal Willdenow or of other related species of Acacia (Fam. Leguminosae) [8]. Gum arabic is approved for use as food additives by the US Food and Drug Administration and is on the list of substances that is a generally recognized as safe (GRAS) with speciic limitations [9]. Gum arabic is the oldest and best known of all the tree gum exudates from certain species of Acacia, family leguminosae. he chemical and physicochemical properties of this gum can vary signiicantly depending on the source, tree age, time of exudation, type of storage and climatic conditions [10]. Gum arabic is widely used in the food industry, mainly to impart desirable qualities through its inluence over viscosity, body and texture. In aqueous systems, it is used as an emulsiier, stabilizer, thickener, adhesive, and to prevent crystallization of sugar and the formation of ice crystals. Other hydrocolloids are also used for these purposes [11]. *Corresponding author: Dr. Sharoba AM, Food Science Department, Moshtohor Faculty of Agriculture, Benha University, Egypt, Fax:+20132467786; Tel: +2 012 21463079; E-mail: ashraf_sharoba@yahoo.com Received June 05, 2012; Accepted July 25, 2012; Published July 29, 2012 Citation: Sharoba AM, El-Desouky AI, Mahmoud MH (2012) Effect of Addition Some Hydrocolloids and Sweeteners on Flow Behavior and Sensory Properties of Papaya-Apricot Nectar Blends. J Food Process Technol 3:170. doi:10.4172/21577110.1000170 Copyright: © 2012 Sharoba AM, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Volume 3 • Issue 8 • 1000170 Citation: Sharoba AM, El-Desouky AI, Mahmoud MH (2012) Effect of Addition Some Hydrocolloids and Sweeteners on Flow Behavior and Sensory Properties of Papaya-Apricot Nectar Blends. J Food Process Technol 3:170. doi:10.4172/2157-7110.1000170 Page 2 of 7 Xanthan gum has been used in a wide variety of foods for a number of important reasons, including emulsion stabilization, temperature stability, compatibility with food ingredients, and its pseudoplastic rheological properties [12]. Guar gum is used as a gelling and thickening agent in many food products such as sauces, syrups, ice cream, instant foods, beverages, and confectionaries [13,14]. Guar gum and its derivatives are also extensively used in various industries such as mining, paper, textile, ceramic, paint, cosmetic, pharmaceutical and explosives [14]. Stevia rebaudiana Bertoni, belonging to the Compositae family, is a sweet herb native to Brazil and Paraguay. Stevia sweeteners, extracts from the leaves of this herb, are commercially available in Japan, Korea, China, South-East Asia and South America, where they have been used for some decades to sweeten a variety of foods including beverages, confectionery, pickled vegetables and seafoods. Recently, stevia extracts have been extensively used as the dietary supplements in USA [15]. he high-intensity sweetener aspartame has been consumed in more than 6000 products by hundreds of millions of people in countries around the world [16]. Aspartame and mixtures of aspartame+acesulfame K are used instead of sucrose to sweeten many beverages and dairy products aimed at weight-conscious consumers. Many authors have studied the sensory properties of these high intensity sweeteners, especially with respect to their atertaste [17]. In fruit juice and beverage, sensory properties and organoleptic attributes of the inal products are inluenced by the several factors such as type and amount of acids and sweeteners [18]. Flow properties of fruit purees are of considerable interest in the development of fruit products for technological and marketing reasons. Together with others, they provide the information necessary for the optimum design of unit processes; contribute to the quality control in both manufacturing processes and inal product; limit the acceptability and the ield of application of a new product; and inally, they are a powerful tool into understanding molecular structure changes [19-21]. Blendes of papaya and apricot nectar appear that the nectar blends Blends No B* (1) Control B (2) B (3) * Mixed papaya puree+apricot juice containing equal percentage of papaya puree and apricot juice had the higher score in all attributes and acceptable to panelists due to better consistency and lavor [22]. Accordingly, this work was carried out to study the efect of addition of some hydrocolloids and sweeteners on sensory and rheological properties of papaya-apricot nectar. Materials and Methods Materials Apricot fruits (Prunus armeniaca) variety Amar were picked at the ripe stage from Amar village, Qalyoubia Governorate, Egypt. he fruits weight ranged from 60 to 65g. Papaya fruits (Carica papaya L.cv. Sunrise Solo) are usually collected green mature from the farm of Moshtohor Faculty of Agriculture, Benha University, Egypt. he fruits weight ranged from 750 to 1750g. he fruit surface was treated by H2O2 5% as disinfectant. It ripened under storage at room temperature for 3-4 days. Sweeteners: Aspartame was obtained from Hortimex, 62-510 Konin, Poland. Stevioside was obtained from Jining Yunhe Stevioside Co., Ltd, Shandong, China. Hydrocolloids: Guar gum and Xanthan gum were obtained from CP Kelco Germany GmbH, 23755 Grossenbrode, Germany. Arabic gum was obtained from Hortimex, 62-510 Konin, Poland. Methods Processing: • Preparation of papaya-apricot nectar samples: he papaya puree and apricot juice (1:1) were mixed together as recommended [22]. his mixture was used to prepare the formulas indicated in Table (A). Nectars pH was adjusted to 3.5 by adding citric acid solution (50% w/v), [23,24]. Methods: • Sensory evaluation: Sensory evaluation was carried out by Sugar solution or water º Hydrocolloids Sweeteners 25% mixed papaya puree+apricot juice 75% sugar solution (18 ± 0.5 brix) - - 25% mixed papaya puree+apricot juice 75% water - 1.2 g/L aspartame** 25% mixed papaya puree+apricot juice 75% water - 1.2 g/L stevioside B (4) 25% mixed papaya puree+apricot juice 75% sugar solution (17.5 ± 0.5 º brix) 0.5% guar gum - B (5) 25% mixed papaya puree+apricot juice 75% sugar solution (17.5 ± 0.5 º brix) 0.5% arabic gum - B (6) 25% mixed papaya puree+apricot juice 75% sugar solution (17.5 ± 0.5 º brix) 0.5% xanthan gum - B (7) 25% mixed papaya puree+apricot juice 74.5% water 0.5% guar gum 1.2 g/L aspartame B (8) 25% mixed papaya puree+apricot juice 74.5% water 0.5% arabic gum 1.2 g/L aspartame B (9) 25% mixed papaya puree+apricot juice 74.5% water 0.5% xanthan gum 1.2 g/L aspartame B (10) 25% mixed papaya puree+apricot juice 74.5% water 0.5% guar gum 1.2 g/L stevioside B (11) 25% mixed papaya puree+apricot juice 74.5% water 0.5% arabic gum 1.2 g/L stevioside B (12) 25% mixed papaya puree+apricot juice 74.5% water 0.5% xanthan gum 1.2 g/L stevioside B =Blend ** Sweeteners were added 1.2g/L of inal prepared nectar Table A: formulas of papaya-apricot nectar samples. J Food Process Technol ISSN:2157-7110 JFPT, an open access journal Volume 3 • Issue 8 • 1000170 Citation: Sharoba AM, El-Desouky AI, Mahmoud MH (2012) Effect of Addition Some Hydrocolloids and Sweeteners on Flow Behavior and Sensory Properties of Papaya-Apricot Nectar Blends. J Food Process Technol 3:170. doi:10.4172/2157-7110.1000170 Page 3 of 7 a properly well trained panel of 12 panelists. hey were selected if their individual scores in 10 diferent tests showed a reproducibility of 90%. he 12 member internal panel evaluated the diferent papaya and apricot nectar blends for color, texture, taste, lavor, mouth feel (smoothness, consistency, spread ability) and overall acceptability. Mineral water was used by the panelists to rinse the mouth between samples, according [25]. he sensory evaluation of papaya-apricot nectar was carried out at two phase. he irst phase was done to select the best concentration of adding each hydrocolloids or sweeteners in papaya-apricot nectar. he second phase was done to know the best blends of hydrocolloids and sweeteners in papaya-apricot nectar. • Selection of the best concentration of hydrocolloid and sweeteners: Many samples of papaya-apricot nectars were prepared containing diferent concentration of guar gum, xanthan gum and arabic gum as hydrocolloid and aspartame and stevioside as sweeteners. Each additive was added alone in papaya-apricot nectar. All samples of papaya-apricot nectar were subjected for sensory evaluation to know the best concentration of additives had high acceptability in sensory attributes. he concentration of additives which had high score in sensory evaluation was used for preparing inished papaya-apricot nectars samples which used to complete this study. • Rheological measurements: Viscosity measurement was carried out by the Brookield Digital Viscometer Model DV-II+ (USA) with 18 rotational speeds for comprehensive data gathering (0.3, 0.5, 0.6, 1.0, 1.5, 2.0, 2.5, 3, 4, 5, 6, 10, 12, 20, 30, 50, 60 and 100 rpm). he Brookield small sample adapter spindle was used. Data was analyzed by using Universal Sotware US200, PhysicaGermany. Each value of rheological parameters is the average of three replicates. Herschel-Bulkley and Bingham plastic math models provide a numerically and graphically analyze the behavior of data sets. • Herschel-Bulkley model: It describes the low curve of a material with a yield stress and shear thinning or shear thickening behavior at stresses above the yield to calculate the viscosity and yield point of ideal-viscous luids. τ = τOHB + K γ n (1) where: τ = Shear stress (Pa) τOHB= Yield stress, shear stress at zero shear rate, (Pa) K = Consistency index (Pa.sn) γ = Shear rate (sec-1) n = Flow index (dimensionless) he calculated parameters for this model are: Herschel-Bulkley yield stress (τOHB), Consistency index (K) and Flow index (n). τ = τOB + ηB γ Bingham Plastic: he Bingham equation is (2) where: τ = Shear stress (Pa) τOB=Yield stress, shear stress at zero shear rate, (Pa) ηB = Plastic viscosity (Pa.s) = Shear rate (sec-1) γ J Food Process Technol ISSN:2157-7110 JFPT, an open access journal he calculated parameters for this model are: Plastic (apparent) viscosity (ηB) and Bingham yield stress (τOB). he efect of temperature on viscosity and low activation energy: Activation energy was calculated using Arrhenius-type equation as mentioned [26,27] η = η∞ exp (Ea/ RT) Where η is the viscosity, η∞ is a constant, Ea is the activation energy of low (J/mol) R is the gas constant, and T is the absolute temperature in K. • hixotropic area: hixotropic area calculates the area between two curves, commonly the up and down curves of a shear rate sweep (the gab area between the ascending and descending rheogram curves). his area is given in (Pas-1) and is oten used as a measure of a sample’s thixotropy. Also the thixotropic area is a measure for the destruction (viscosity decrease at thixotropic samples) or construction (at rheopectic samples) of structures at inclining and declining load. Statistical Analysis Data for the sensory evaluation of all nectar preparations were subjected to the analysis of variance (ANOVA) followed by multiple comparisons using least signiicant diference, (L.S.D.0.05) [28]. Results and Discussion Efect of mixing some sweeteners and hydrocolloid blends in sensory properties of apricot-papaya nectar: Organoleptic parameters are good indicating the possibility of nectar for acceptability. In this study we used (aspartame and stevioside) to produce low-calorie fruit nectars; aspartame has a clean, sugar-like taste, enhances fruit and can be safely used under heat with some loss of sweetness at higher temperatures. It is primarily responsible for the growth of the low-calorie and reduced-calorie product market in the past two decades and is today an important component of thousands of foods and beverages. Because aspartame helps impart a good, sweettasting lavor to low-calorie and reduced-calorie foods and beverages, it is helpful to diabetics and beneicial in weight control by managing caloric intake while still maintaining a healthful diet. In the other hand stevioside is a low-calorie sweetener derived from Stevia rebaudiana, is 300 times sweeter than sucrose. he plant leaves have been used for centuries in Paraguay to sweeten bitter beverages and to make tea. Stevioside is highly soluble in water, very sweet in taste, and synergistic with other sweeteners [29]. Color, texture, taste, lavor, mouth feel and overall acceptability of papaya-apricot nectar with diferent blends of sweetness and hydrocolloid were organoleptically evaluated; the results are indicated in Table (1). Non tabulated results for sensory evaluation of papaya-apricot nectar indicated that the best percentage additive of hydrocolloids for enhanced the texture of nectar was 0.5% for either guar, arabic or xanthan gum. Concerning for sweeteners, the best percentage additive of sweeteners was 1.2g/l for either aspartame or stevoside. Nearly, the acceptable percentages of adding hydrocolloids and sweeteners were in agreement with those obtained, whom were used hydrocolloids and sweeteners in other fruits and vegetables products [30-32]. So, samples of papaya-apricot nectar were prepared containing each acceptable percentage of hydrocolloids and sweeteners or blends of some of them. Volume 3 • Issue 8 • 1000170 Citation: Sharoba AM, El-Desouky AI, Mahmoud MH (2012) Effect of Addition Some Hydrocolloids and Sweeteners on Flow Behavior and Sensory Properties of Papaya-Apricot Nectar Blends. J Food Process Technol 3:170. doi:10.4172/2157-7110.1000170 Page 4 of 7 Sensory evaluation of papaya-apricot nectar Data in Table (1) indicated that papaya-apricot nectar containing guar gum, xanthan gum or arabic gum had high score in overall all acceptability. All papaya-apricot nectar containing hydrocolloids were acceptable more than control papaya-apricot nectar which free from hydrocolloids. Also from the data for overall all acceptability, can grouped the papaya-apricot nectar to four groups as statically analyzed and indicated by letter in the table as follow: group one which mentioned before had letter (a) which contained hydrocolloid only, second group which had letter between (b to d) which had hydrocolloid with sweetener, or control and hired group had letter (e) containing sweetener. All nectar samples including control had high average score in overall all acceptability more than eighty except nectar samples containing sweetener alone. So, can conclude to use hydrocolloid alone or and sweetener when prepare nectar fruits. Mouth feel is important properties in sensory evaluation. Data in Table (1) indicated that all nectar samples can divided to two groups as follow: irst group, included control nectar sample and nectars containing each hydrocolloid. Second, group other nectars containing hydrocolloid with sweetener or sweetener only. Neutrally, the papaya-apricot nectar (control) had high score in color, lavor and taste among all nectar samples. On the other hand all nectars samples containing hydrocolloids had score in texture more than control samples. It’s worthy that the papaya-apricot nectar containing any sweetener without adding hydrocolloids had the lowest score in sensory properties between all papaya-apricot nectar. purees containing particles with non uniform sizes and shapes, stability may sometimes be diicult to achieve at either very low or high shear rates. At high shear rates, turbulent low conditions are likely to be induced by the dispersed particles, resulting in structural breakdown of the sample. Even with these complexities, most purees generally exhibit non-Newtonian low patterns. herefore, the non-Newtonian models in Eqs. (1) and (2) were considered for their suitability in describing the low of papaya-apricot nectar. he Herschel-Bulkley model has been used extensively in studies on handling and heating/cooling of foods because it gives good description of luid low behavior in the shear rate range that is easily measured by most rheological instruments. Most fruit purees and nectars show shear-thinning behavior (0<n<1), a situation that may be regarded as an indication of breakdown of structural units in a food due to the hydrodynamic forces generated during shear [34]. Quantiication of low parameters within some deined shear rate ranges may be a good way of studying these changes in product structure. If the foodstuf has a inite yield stress, the yield term can be included in the Power Law model to yield the HerschelBulkley (HB) model: he yield stress can be determined experimentally, graphically as explained [35], or calculated by a separate model. Selection of rheology models he HB model is convenient because Newtonian, Power law and Bingham Fluids can be considered as special cases obeying this generalized model [36]. However, the yield stress obtained by itting the three parameter HB model is strongly dependent on the selected shear rate range [35]. As mentioned that choice of an appropriate model to relate product viscosity to brix number and shear rate depends essentially on the intended application and use of a suitable instrument to determine the model parameters [33]. During experiments, laminar low conditions are necessary for accurate measurements; and for fruit he Correlation coeicients was used to determine how good the models it the data. Based on Correlation coeicients and overall suitability of the models considered, the Herschel-Bulkley and Bingham models were selected to describe the rheological behavior of papaya-apricot nectar samples. Sensory attributes (max. score) Products (Nectar Blends) Color (20) Texture (20) Taste (20) Flavor (20) Mouthfeel (20) Overall acceptability (100) Papaya-apricot nectar (control) (B1) 19.81a±0.38 16.92c±0.64 18.07a±0.54 19.48a±0.34 18.21a±0.28 83.17cd±2.45 PAN with aspartame (B2) 11.27e±0.08 8.22d±0.86 10.15d±0.47 11.08e±0.83 13.65b±0.84 71.16e±1.07 PAN with stevioside (B3) 11.64e±0.42 8.34d±0.99 9.63d±0.83 10.39e±0.71 13.84b ±0.57 69.10e±2.08 PAN with guar gum (B4) 18.57b±0.39 19.41a±0.14 17.64ab±1.23 17.82b±0.35 18.94a±0.61 96.14a±1.83 PAN with arabic gum (B5) 18.31b±0.48 17.86abc±0.53 16.81ab±0.85 17.21b±0.96 18.04a±0.34 93.18a±0.97 PAN with xanthan gum (B6) 18.94b±0.24 18.87ab±0.67 17.52ab±0.62 17.91b±0.67 19.01a±0.81 95.53a±0.84 PAN with (aspartame + guar gum) (B7) 15.41cd±0.19 18.60abc±1.04 15.99bc±0.97 15.86c±0.96 14.58b±0.70 88.17b±1.27 PAN with (aspartame + arabic gum) (B8) 14.87d±0.54 17.39bc±0.82 14.86c±1.28 15.44d±0.51 14.33b±0.93 83.11cd±1.36 PAN with (aspartame + xanthan gum) (B9) 15.68c±0.61 18.12abc±0.32 15.64bc±0.25 15.91c±0.28 14.61b±0.82 86.17bc±1.57 PAN with (stevioside + guar gum) (B10) 15.36cd±0.27 18.43abc±0.55 15.68bc±0.31 14.79d±0.37 14.47b±0.71 84.75bcd±1.25 PAN with (stevioside + arabic gum) (B11) 14.81d±0.69 17.11bc±0.36 14.77c±0.52 14.68d±0.68 14.32b±0.68 81.17d±2.04 PAN with (stevioside + xanthan gum) (B12) 15.54c±0.40 18.04abc±0.75 15.65bc±0.61 14.89d±0.72 14.58b±0.94 83.19cd±1.67 0.67 1.81 1.76 0.81 1.64 4.57 L.S.D at P<0.05 a,b There is no signiicant different ( P > 0.05) between any two means, within the same attribute have the same letter. Table 1: Sensory properties of papaya and apricot nectar (PAN) blends. J Food Process Technol ISSN:2157-7110 JFPT, an open access journal Volume 3 • Issue 8 • 1000170 Citation: Sharoba AM, El-Desouky AI, Mahmoud MH (2012) Effect of Addition Some Hydrocolloids and Sweeteners on Flow Behavior and Sensory Properties of Papaya-Apricot Nectar Blends. J Food Process Technol 3:170. doi:10.4172/2157-7110.1000170 Page 5 of 7 Efect of mixing some sweeteners and hydrocolloid blends on rheological characterization of apricot-papaya nectar he rheological behavior of hydrocolloids is of special importance when they are used to modify low behavior. It is also well recognized that rheological properties play a role in process design, evaluation and modeling. hese properties are sometimes measured as an indicator of product quality (e.g. indication of total solids or change in molecular size). Rheological data are required for calculation in any process involving luid low (e.g. pump sizing, extraction, iltration, extrusion, puriication) and play an important role in the analyses of low conditions in food processes such as pasteurization, evaporation, drying and aseptic processing. In this study three hydrocolloids (guar gum, xanthan gum and arabic gum) were used in papaya-apricot nectar due to improve the rheological properties. Shear rate – shear stress curves (recorded by Brookield Digital Viscometer) and data in Tables (2-3) for nectar samples showed non-Newtonian pseudoplastic with yield stress luids as the apparent viscosity decreases with increasing shear rate, therefore they exhibit a shear-thinning behavior. Several models have been used to characterize the low behavior of papaya-apricot nectars mixed with gum and sweeteners and among them Herschel-Bulkley model has been frequently used for the determination of rheological properties of the fruit juices and nectars. In addition, Bingham model has been also used for the characterization of luid foods such as fruit juices and nectars. he parameters obtained for the Herschel-Bulkely and Bingham models are summarized in Tables (2–3). he Correlation coeicients, Nectar samples Papaya-apricot nectar (control) (B1) PAN with aspartame (B2) PAN with stevioside (B3) PAN with Guar gum (B4) PAN with Arabic gum (B5) PAN with Xanthan gum (B6) t C for all cases, were higher than 0.964. Higher measure temperatures showed slightly lower values (K, ηB τ0HB and τ0B), this trend of results are in according to references [35,37]. Higher yield stress values were observed due to addition of gums and lower temperatures. his is in agreement .It has been recognized that the yield stress is a useful property of gums when they are used as binders, because it helps keep various components of the food formulation in place [37]. Gums addition showed that guar gum had generally higher synergistic efect than xanthan and arabic gum when used with papayaapricot, this trend is similar with the fond guar gum had high low behavior parameters than arabic gum [38]. It could be concluded in the view of the results that guar gum particularly was more efective in increasing “K” values of papaya-apricot nectar. In the case of guar its molecular mass and galactose:mannose ratio strongly depended on the origin of the gum. In addition, the branching degree of the hydrocolloid, which is higher for guar, can also play an important part in the galactomannan-nectar compound interactions according [38]. Similar trends were observed for other nectars content gums. he “K” values were increased with adding gum suggesting better synergy when they used to combine with papaya-apricot nectar. Combination of papaya-apricot nectar and guar gum may help attaining desired consistency. Guar gum is used in food industry for thickening purpose since it is more economical compared to other stabilizers. Since the synergy between guar and papaya-apricot nectar in terms of increasing the consistency of nectars was found better in this study, therefore the combined of guar- papaya-apricot nectar mix could be recommended in diferent fruit nectars formulations. Flow behavior index of nectar samples decreased with temperature. Parameters for different rheology models Herschel-Bulkley ° Thixotropy (Pa.s-1) Bingham τ0HB K n r ηB τ0B r 5 4.89 4.79 0.159 0.999 22.31 4.83 0.996 138.01 25 4.14 4.55 0.153 0.999 19.11 4.24 0.996 124.15 50 3.82 4.28 0.148 0.999 15.87 3.94 0.992 116.81 75 3.51 3.96 0.139 0.998 12.12 3.75 0.990 107.46 5 0.91 2.33 0.122 0.984 13.46 1.21 0.984 38.11 25 0.63 2.09 0.121 0.986 10.83 1.05 0.986 31.67 50 0.42 1.93 0.119 0.975 9.14 0.91 0.976 25.08 75 0.19 1.77 0.120 0.972 7.25 0.78 0.971 18.40 5 0.68 2.28 0.113 0.996 13.27 0.89 0.988 38.45 25 0.49 2.04 0.112 0.997 10.75 0.74 0.982 31.27 50 0.32 1.86 0.112 0.991 9.21 0.65 0.965 25.19 75 0.17 1.65 0.109 0.985 7.34 0.55 0.966 18.15 5 8.12 15.83 0.603 0.999 49.83 8.96 0.995 74.34 25 7.54 14.77 0.582 0.999 46.81 8.40 0.997 71.81 50 5.84 12.46 0.531 0.997 44.31 8.03 0.991 68.50 75 5.12 9.11 0.485 0.990 42.10 7.79 0.990 64.39 5 7.15 11.65 0.335 0.999 43.12 7.74 0.999 81.07 25 6.28 8.93 0.333 0.999 41.08 7.09 0.996 75.45 50 5.20 7.58 0.321 0.999 38.91 6.73 0.991 70.29 75 4.06 6.42 0.310 0.999 35.67 6.14 0.979 66.49 5 7.78 13.08 0.589 0.999 46.34 8.41 0.993 78.64 25 6.34 10.67 0.551 0.999 44.09 8.12 0.991 74.38 50 5.83 10.11 0.501 0.998 42.33 7.76 0.991 71.12 75 5.04 8.63 0.480 0.999 40.46 7.31 0.988 67.34 Table 2: Effect of addition some sweetness and hydrocolloids on rheological parameters of papaya and apricot nectar. J Food Process Technol ISSN:2157-7110 JFPT, an open access journal Volume 3 • Issue 8 • 1000170 Citation: Sharoba AM, El-Desouky AI, Mahmoud MH (2012) Effect of Addition Some Hydrocolloids and Sweeteners on Flow Behavior and Sensory Properties of Papaya-Apricot Nectar Blends. J Food Process Technol 3:170. doi:10.4172/2157-7110.1000170 Page 6 of 7 Nectar samples aspartame with Guar gum (B7) aspartame with Arabic gum (B8) aspartame with Xanthan gum (B9) Stevioside with Guar gum (B10) Stevioside with Arabic gum (B11) Stevioside with Xanthan gum (B12) Parameters for different rheology models t C Herschel-Bulkley ° Thixotropy (Pa.s-1) Bingham τ0HB K n r ηB τ0B r 5 6.63 12.54 0.491 0.999 42.10 7.33 0.998 68.15 25 5.46 11.29 0.443 0.999 39.89 6.79 0.973 65.47 50 4.62 10.74 0.399 0.998 37.82 6.27 0.968 61.33 75 3.95 10.06 0.379 0.995 34.43 5.76 0.967 58.94 5 4.92 10.11 0.294 0.999 36.84 5.68 0.999 78.19 25 3.98 8.24 0.259 0.999 35.01 5.13 0.998 70.01 50 3.35 6.71 0.244 0.999 32.54 4.65 0.991 67.87 75 2.96 5.94 0.225 0.996 28.49 4.18 0.986 64.28 5 5.51 11.37 0.479 0.999 40.22 6.28 0.997 75.28 25 4.43 9.14 0.431 0.997 37.85 5.81 0.992 71.14 50 3.89 8.58 0.397 0.994 34.99 5.34 0.988 69.34 75 3.05 7.86 0.374 0.990 32.41 4.79 0.964 66.11 5 6.43 12.21 0.474 0.999 41.35 7.26 0.995 69.74 25 5.37 11.03 0.431 0.995 39.15 6.73 0.994 65.96 50 4.51 10.40 0.394 0.995 37.14 6.16 0.987 62.14 75 3.86 9.81 0.368 0.991 33.74 5.71 0.976 59.81 5 4.79 9.86 0.287 0.999 36.16 5.65 0.988 78.37 25 3.88 8.06 0.253 0.993 34.57 5.09 0.983 73.15 50 3.13 6.63 0.235 0.995 31.90 4.54 0.971 70.13 75 2.74 5.71 0.213 0.987 27.61 4.11 0.972 67.81 5 5.21 11.08 0.461 0.999 40.01 6.22 0.985 77.11 25 4.17 9.02 0.417 0.991 37.28 5.73 0.982 73.21 50 3.66 8.34 0.391 0.989 34.32 5.22 0.982 71.14 75 2.89 7.56 0.366 0.990 31.74 4.71 0.979 68.27 Table 3: Effect mixing of sweetness and hydrocolloids on rheological parameters of papaya and apricot nectar. Ea (kJ/mol.) η∞ (mPa.s) Correlation coeficient (r2) Temperature range (°C) Papaya-apricot nectar (control) (B1) 9.34 3.11 0.999 5-75 PAN with aspartame (B2) 5.84 1.95 0.956 5-75 PAN with stevioside (B3) 5.13 1.87 0.943 5-75 PAN with guar gum (B4) 16.48 4.20 0.999 5-75 PAN with arabic gum (B5) 14.39 4.12 0.999 5-75 PAN with xanthan gum (B6) 15.96 4.16 0.999 5-75 PAN with (aspartame+ guar gum) (B7) 11.23 6.24 0.994 5-75 PAN with (aspartame+ arabic gum) (B8) 10.55 6.08 0.995 5-75 PAN with (aspartame+xanthan gum) (B9) 10.98 6.13 0.991 5-75 PAN with (Stevioside+guar gum) (B10) 11.01 6.19 0.986 5-75 PAN with (Stevioside+arabic gum) (B11) 10.37 5.91 0.968 5-75 PAN with (Stevioside+xanthan gum) (B12) 10.63 5.64 0.974 5-75 Nectar sample Table 4: Parameters for the Arrhenius equation to predict the variation of viscosity of papaya-apricot nectar blended with some sweeteners and hydrocolloids. Addition of sweeteners to the papaya-apricot nectar caused a decreased in values (K, ηB τ0HB and τ0B). he “n” values increased sharply with adding gums to papaya-apricot nectar, while they decreased with adding sweeteners. Both demonstrated non-Newtonian low. hixotropy behavior of papaya-apricot nectar and efect of addition of some hydrocolloids and sweeteners From the shear rate-shear stress curves, nectar samples exhibited thixotropy, exhibit time dependent properties, which mean that the apparent viscosity or consistency will decrease with time. he area enclosed by the hysteresis loop signiies the degree of structural breakdown during steady shearing. he upper curve of the rheogram was found to be higher compared to the down ward curve which indicated a thinning of nectar samples with shearing. Similar behavior was observed [26,27,39-42]. he thixotropy (Pa/s) values increased J Food Process Technol ISSN:2157-7110 JFPT, an open access journal with increasing total solids nectar samples. All hydrocolloid decrease the thixotropy. Efect of temperature on low behavior of nectar samples Temperature has an important inluence on the low behavior of nectar samples content hydrocolloids. Since diferent temperatures are usually encountered during processing of hydrocolloids, their rheological properties are studied as a function of temperature. he efect of temperature on the apparent viscosity at a speciied shear rate is generally expressed by an Arrhenius-type model. he Arrhenius equation to a great extent explains the relationship between the temperature and viscosity. he viscosity is dependent up on the intermolecular distances. As the temperature is increased, the intermolecular distances increase and therefore the viscosity will decrease for these main reasons. he viscosity is a function of temperature and the dissolved solid concentration. Volume 3 • Issue 8 • 1000170 Citation: Sharoba AM, El-Desouky AI, Mahmoud MH (2012) Effect of Addition Some Hydrocolloids and Sweeteners on Flow Behavior and Sensory Properties of Papaya-Apricot Nectar Blends. J Food Process Technol 3:170. doi:10.4172/2157-7110.1000170 Page 7 of 7 Results presented in Table (4) showed the variation in viscosity with temperature described by an Arrhenius-type. he activation energy of nectar samples ranged between 5.13 to 16.48 kJ/mol. he activation energy increased with addition hydrocolloids and decreased with addition sweeteners. he same trend was observed for η∞ factors were increasing with increasing total solids and increased with addition hydrocolloids while decreased with addition sweeteners. From the obtained results it can be concluded that the hydrocolloids were the most efective to improve the viscosity of nectar samples. he efective and best increased of the viscosity was done by addition guar gum. Conclusions From the obtained data, thickened nectars showed a shear-thinning behavior, and their viscosity increased with adding thickeners with sugar, rheology models are recommended that adequately described the stress-rate relationships for the thickened luids. he parameters of the models can be used to estimate the viscosity of fruits nectar. References 1. Liebman B (1992). Fresh fruit: A papaya a day? Nutrition Action Healthletter 10-11. 2. USDA National Nutrient Database for Standard Reference (2008). 3. Lim YY, Lim TT, Tee JJ, (2007) Antioxidant properties of several tropical fruits: A comparative study. Food Chem 103: 1003-1008. 4. 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J Texture Stud 31: 287-295. 41. Nindo CI, Tang J, Powers JR, Singh P (2005) Viscosity of blueberry and raspberry juices for processing applications. J Food Eng 69: 343-350 . 42. Ahmed J, Ramaswamy HS, Hiremath N (2005) The effect of high pressure treatment on rheological characteristics and colour of mango pulp .Int J Food Sci Technol 40: 885-895. Volume 3 • Issue 8 • 1000170