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核桃乳饮料外文资料

Carbohydrate Polymers 87 (2012) 1611–1619

Contents lists available at SciVerse ScienceDirect

Carbohydrate

Polymers

j o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /c a r b p o

l

Development of an optimal formulation for oxidative stability of

walnut-beverage emulsions based on gum arabic and xanthan gum using response surface methodology

Seyed Mohammad Taghi Gharibzahedi,Seyed Mohammad Mousavi ?,Manouchehr Hamedi,Faramarz Khodaiyan,Seyed Hadi Razavi

Department of Food Science,Engineering and Technology,Faculty of Agricultural Engineering and Technology,University of Tehran,P.O.Box 4111,Karaj 31587-77871,Iran

a r t i c l e

i n f o

Article history:

Received 29July 2011

Received in revised form 4September 2011Accepted 23September 2011

Available online 29 September 2011

Keywords:

Walnut oil-in-water emulsion Xanthan gum Lipid oxidation Peroxide value Droplet size

Response surface methodology (RSM)

a b s t r a c t

The susceptibility of lipids to oxidation is one of the most fundamental problems in oil-in-water emul-sions.A response surface methodology 5-level-3-factor central-composite rotatable design was applied to study the effects of key formula ingredients including walnut oil (WO,3–6%,w/w),gum arabic (GA,5–10%,w/w)and xanthan gum (XG,0.05–0.15%,w/w)on lipid oxidation in walnut-beverage emulsions.During 30days’storage,the oxidation process was monitored by evaluating the peroxide value,anisidine value and total oxidation (Totox)value in different emulsion https://www.sodocs.net/doc/279596993.html,e of XG as a stabilizer at high concentrations considerably inhibited the oxidation of WO in the prepared emulsions.The experimental data were satisfactorily ?tted to quadratic models using multiple regression analysis.The optimum con-ditions to obtain the minimum peroxide (0.923mequiv.O 2/kg oil),anisidine (0.500)and Totox (2.347)values are met when a walnut-beverage emulsion is formulated with 3%WO,10%GA and 0.12%XG.

? 2011 Elsevier Ltd. All rights reserved.

1.Introduction

Beverage emulsions are thermodynamically unstable systems due to the positive free energy needed to increase the surface area between the oil and water phases,and the density difference between these two phases.They tend to separate into two layers over time through a number of mechanisms,including cream-ing,coalescence,?occulation and Ostwald ripening (McClements &Decker,2000;Mirhosseini,Tan,Hamid,Yusof,&Chern,2009).It is possible to form emulsions that are kinetically stable (metastable)for a reasonable period of time by including substances known as emulsi?ers and/or thickening agents prior to homogenization (Sun,Gunasekaran,&Richards,2007).Gum arabic (GA)due to the excellent emulsifying properties is the most usually applied biopolymer emulsi?er in beverage emulsions.It is surface active,adsorbs to interfaces between oil and water,and facilitates the pro-duction of small droplets by lowering the interfacial tension during homogenization (Buffo,Reineccius,&Oehlert,2001).Xanthan gum (XG)is a non-linear anionic microbial heteropolysaccharide syn-thesized by aerobic fermentation of Xanthomonas campestris ,and has a particularly complicated molecular structure.It is widely

?Corresponding author.Tel.:+982612248804;fax:+982612249453.E-mail address:Mousavi@ut.ac.ir (S.M.Mousavi).

used as an emulsion stabilizer and thickener due to its excel-lent viscosity and dispersion characteristics (such as reversible shear thinning and its ability to disperse in either hot or cold

water)(Krstonoˇ

s i′c,Doki′c,Doki′c,&Dapˇc evi′c,2009).The use of GA biopolymer in combination with XG has revealed for increasing the density of oil droplets,controlling the rheological character-istics of the water phase,and attaining the long-term stability of beverage emulsions (Mirhosseini,Tan,Taherian,&Boo,2009;Taherian,Fustier,&Ramaswamy,2007).Vegetable oil is another critical structural component in the emulsion system.It is added to the formulation of beverage emulsions to achieve desirable optical and rheological properties in the ?nished emulsion-based product (Mirhosseini,Tan,Hamid,&Yusof,2008).This study investigated the feasibility of using walnut oil (WO)as a functional ingredient in the production of concentrated beverage emulsions.The used oil in present study contained the following fatty acids (mol%):0.406%C14:0,8.82%C16:0,0.153%C16:1,3.11%C18:0,25.17%C18:1,50.18%C18:2,12.07%C18:3and 0.133%C20:1as measured by gas chromatography of methyl esters (Gharibzahedi,Mousavi,Hamedi,&Ghasemlou,2012).WO is a good source of essential fatty acids such as linoleic and ?-linolenic acids.These compounds are known to reduce the risk of coronary heart disease,non-fatal myocardial infarction and certain type of cancer (Gharibzahedi,Mousavi,Hamedi,&Khodaiyan,2011;Miraliakbari &Shahidi,2008).

0144-8617/$–see front matter ? 2011 Elsevier Ltd. All rights reserved.doi:10.1016/j.carbpol.2011.09.067

1612S.M.T.Gharibzahedi et al./Carbohydrate Polymers87 (2012) 1611–1619

Table1

Experimental domain of central composite rotatable design(CCRD).

Independent variables Symbol Coded variables levels

Uncodi?ed Codi?ed?1.682(??)?10+1+1.682(+?)

Walnut oil concentration(WO,%w/w)X1x1 1.983 4.567.02

Gum arabic content(GA,%w/w)X2x20.03 3.37.51011.7 Xanthan gum content(XG,%w/w)X3x30.020.050.100.150.18

Strong interest in the functional food market is growing as result of consumer demand for foods that contain some health-promoting components beyond traditional nutrients.The polyunsaturated fatty acids(PUFAs)most commonly found in functional foods are generally in the form of dispersed https://www.sodocs.net/doc/279596993.html,e of oils high in n-3 PUFAs in foods is limited due to their high susceptibility to oxi-dation(Donnelly,Decker,&McClements,1998;McClements& Decker,2000).Lipid oxidation is an unfavorable process in most foods such as beverage emulsions because it leads to the expan-sion and development of potentially toxic reaction products and undesirable changes in the quality and characteristics of foods, such as taste,?avor,texture,appearance,shelf life and nutritional value(Frankel,Satue-Gracia,Meyer,&German,2002;McClements &Decker,2000;Osborn&Akoh,2004).Duh,Yen,and Yen(1999) concluded that the oxidative stability of soybean oil-in-water emul-sions can be improved by adding emulsi?ers.Donnelly et al.(1998) found that controlling the type and concentration of emulsi?er and the size of oil droplets at the oil–water interface can increase the oxidative stability of emulsi?ed menhaden oil.Shimada,Fujikawa, Yahara,and Nakamura(1992)and Sun et al.(2007)also demon-strated that the presence of stabilizers such as XG can retard lipid oxidation in o/w emulsions.

Response surface methodology(RSM)is a collection of useful mathematical and statistical procedures that possess the advan-tage of reducing number of experimental trials needed to scrutinize multiple factors and their interactions in comparison to other approaches(Myers&Montgomery,2002).Tiliu and Yang(2011) optimized the emulsi?cation and microencapsulation ef?ciency and oxidative stability of evening primrose oil(EPO)with differ-ent emulsi?ers during storage using RSM.However,to the best of our knowledge,there is no speci?c study on the effect of various concentrations of the main emulsion components on the oxidative stability of WO-in-water beverage emulsions by RSM.Therefore, this study aimed to determine the optimum formulation of walnut-beverage emulsions with RSM for minimizing oxidative damage.

2.Materials and methods

2.1.Materials

Potassium sorbate,sodium benzoate and food grade citric acid(anhydrous)were obtained from Chisso Co.(Tokyo,Japan), Fars Chemical Industry Co.(Shiraz,Iran)and Kimia Gharb-Gostar Industry Co.(Kermanshah,Iran),respectively.GA was purchased from Merck KGaA(Darmstadt,Germany).XG was provided from Sigma–Aldrich(Oakville,ON,Canada).WO was obtained by press-ing Toyserkan cultivar walnuts.The oil expression was carried out with a screw press(Model NA21T,Zeith,Kerman,Iran),with a 5mm restriction die and a screw speed of20rpm.

2.2.Emulsion preparation

For the preparation of walnut-beverage emulsions,the method of Gharibzahedi et al.(2012)was adopted with minor modi?ca-tions.20WO-in-water emulsions were composed of GA(5–10%, w/w),XG(0.05–0.15%,w/w),WO(3–6%,w/w),citric acid(0.4%, w/w),potassium sorbate(0.1%,w/w),sodium benzoate(0.1%,w/w)and deionized water.These components were prepared for the optimization procedure based on a central rotatable composite design(CCRD)(Table1).To prepare the water phase,potassium sor-bate,sodium benzoate and citric acid were dispersed in deionized water(≈60?C)using a blender(IKA-WERK,RW20DZM,Staufen, Germany).During mixing,GA was gradually added to the deionized water(≈60?C),and the solution was mixed for an extra5min to fur-ther facilitate hydration.To achieve full hydration,the mixture was kept at room temperature overnight.XG solution was prepared sep-arately by dissolving XG in deionized water with shaking and then mixed with the GA solution by using a high-speed blender.While the water phase was mixing,the cold-pressed WO without addition of weighting agents was slowly added to the water phase to pre-pare an initial coarse emulsion(Mirhosseini et al.,2008).To obtain ?ne emulsi?cation with small average droplet size(<1?m)and narrow particle-size distribution,pre-emulsions were subjected to pre-homogenization using a high shear blender(IKA-WERK,Ultra Turrax,T25basic,Staufen,Germany)for3min and passed through a high-pressure homogenizer(APV2000,Denmark)three times(30, 25and20MPa).At least two separate emulsions were prepared for each treatment.

2.3.Droplet size measurement

Mean droplet size of WO-in-water emulsions was determined by laser light scattering(Mastersizer2000S,Malvern Instruments Ltd.,Malvern,UK).Sample analysis was carried out during30days based on Mie theory(Gharibzahedi et al.,2012;Huang,Kakuda,& Cui,2001).The concentrated emulsions were diluted with deion-ized water(1:100)to avoid multiple scattering effects,and placed directly into a metal jar that circulated the sample through the measuring-glass cuvette.A laser beam directed through the diluted emulsions was scattered by the droplets in a characteristic pattern according to their size and detected by an array of photodiodes located behind the cuvette(Buffo et al.,2001).Size distribution was characterized by volumetric percentage and mean particle size of the emulsion droplets obtained using the surface-weighted mean diameter:

D32=

n i d3

i

n i d2

i

where n i is the number of droplets of diameter d i(Tangsuphoom& Coupland,2009).

2.4.Optical microscopy

Emulsions were gently agitated in a glass test tube to ensure homogeneity prior to analysis.A drop of emulsion sample was diluted with1g/l SDS solution and placed on a microscope slide, covered with a cover slip(Koocheki,Kadkhodaee,Mortazavi, Shahidi,&Taherian,2009).Microstructure was visualized by phase-contrast light microscopy(Leica Galen III,Germany)at40×magni?cations and recorded by means of a digital camera(Mavica FD88,Sony company,Japan)mounted on the microscope.Images were made immediately after preparation of emulsion and30days after being stored at temperature room.

S.M.T.Gharibzahedi et al./Carbohydrate Polymers87 (2012) 1611–16191613 Table2

Three-factor central composite rotatable design(CCRD)used for RSM with experimental and predicted values for the independent variables.

Formulation Point type Independent

variables Peroxide value

(mequiv.O2/kg oil)(Y1)

Anisidine value(Y2)Totox value(Y3)

X1X2X3Experimental a Predicted Experimental a Predicted Experimental a Predicted

1Fact?1?1?1 1.230 1.223 1.121 1.094 3.581 3.541

2Fact1?1?1 1.440 1.431 1.621 1.588 4.501 4.451

3Fact?11?1 1.020 1.0600.6070.587 2.647 2.707

4Fact11?1 1.060 1.0480.7820.817 2.902 2.913

5Fact?1?110.9100.9380.5940.555 2.414 2.433

6Fact1?11 1.260 1.2360.6150.631 3.135 3.105

7Fact?1110.7900.8150.3590.388 1.939 2.019

8Fact111 1.070 1.0930.6910.714 2.831 2.901

9Center000 1.140 1.1030.4910.473 2.771 2.679

10Center000 1.050 1.1030.5120.473 2.612 2.679

11Center000 1.220 1.1530.5850.602 3.025 2.908

12Center00 1.170 1.1530.5530.602 2.893 2.908

13Axial?1.6800 1.090 1.0450.9540.985 3.134 3.077

14Axial 1.6800 1.350 1.370 1.487 1.459 4.187 4.199

15Axial0?1.680 1.410 1.423 1.335 1.381 4.155 4.229

16Axial0 1.680 1.120 1.0820.8510.808 3.091 2.972

17Axial00?1.68 1.610 1.610 1.854 1.877 5.074 5.099

18Axial00 1.68 1.350 1.325 1.142 1.121 3.842 3.772

19Center000 1.320 1.3300.954 1.027 3.594 3.688

20Center000 1.270 1.330 1.112 1.027 3.652 3.688

a Mean of triplicate determinations.

2.5.Oxidizing conditions and evaluation of oil oxidation

The procedure described by Osborn and Akoh(2004)was employed for the analysis of the oil oxidation progression in emul-sion samples with minor modi?cation.Oxidation was monitored over a28-day period.In brief,15ml aliquots of the WO-in-water beverage emulsions were stored in covered test tubes and then allowed to oxidize at a thermostated water bath(50?C).In order to determine the levels of hydroperoxide and aldehyde present in the oil,triplicate15ml WO-in-water emulsion samples were taken periodically.By adding isooctane/isopropanol(3:2,v/v),vortexing 3times for10s each,and followed by centrifugation at1000rpm for5min at room temperature,WO was extracted from these emul-sions.The upper layer was removed and the solvent was evaporated under nitrogen gas.Then,the oil samples were weighed in order to accurately determine oxidation progression in each tested sample.

Peroxide values were determined using the International Dairy Foundation method as described previously by Moayedi,Rezaei, Moini,and Keshavarz(2011).Brie?y,about0.25g of obtained oil was weighed into a glass test tube and dissolved in9.7ml of a mixture of chloroform/methanol(4:1,v/v).Then,a drop of ammo-nium thiocyanate solution(30%,w/v)and a drop of ferrous chloride solution(0.35%,w/v)were added.The absorbance of the mixture was measured at500nm using a UV–visible spectrophotometer(U-5100model,Hitachi,Japan),after standing for5min.In addition, a calibration curve was constructed using ferric chloride solutions containing3–15?g of Fe3+.The anisidine value was determined at 350nm in a1.0cm cell of a solution containing1.0g of oil in100ml

Table3

Analysis of variance for the effect of the independent variables on the dependent variables and the regression coef?cients of the?tted quadratic equations obtained from experimental results.

Source DF Peroxide value(mequiv.O2/kg oil)Anisidine value Totox value

Coef?cient Sum of

squares p-Value Coef?cient Sum of

squares

p-Value Coef?cient Sum of

squares

p-Value

Model9 1.1950.4800.00020.701 1.989<0.0001 3.0927.063<0.0001 Linear

ˇ110.0960.1270.00010.1400.271<0.00010.333 1.521<0.0001ˇ21?0.1010.141<0.0001?0.1700.396<0.0001?0.373 1.905<0.0001ˇ31?0.0840.0980.0003?0.2240.689<0.0001?0.394 2.122<0.0001 Quadratic

ˇ111?0.0430.0270.01350.0680.0680.0028–0.004ns

ˇ221–0.010ns–0.008ns–0.013ns

ˇ3310.0480.0330.00770.1670.401<0.00010.264 1.004<0.0001 Interaction

ˇ121–0.007ns–0.001ns–0.030ns

ˇ1310.0470.0180.0329–0.012ns–0.023ns

ˇ231–0.009ns0.1490.1780.00010.2190.3840.0003 Residual80.0210.0300.086

Lack-of-?t50.0150.41710.0170.62630.0630.3626 Pure error30.0060.0130.023

Total190.704 3.27011.225

R20.9560.9850.988

Adj-R20.9070.9680.974

CV 4.37 6.75 3.09

1614S.M.T.Gharibzahedi et al./Carbohydrate Polymers 87 (2012) 1611–1619

00.250.50.7511.251.51.7532

28

24

20

16

12

8

4

P e r o x i d e v a l u e (m e q O 2/k g o i l )

Storage time (day)

00.250.50.7511.251.51.75232

28

24

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4

A n i s i d i n e v a l u e

Storage time (day)

012345632

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T o t o x v a l u e

Storage time (day)

c

a

b

Fig.1.Changes in peroxide value (a),anisidine value (b)and Totox value (c)over storage time at 25±2?C in WO-in-water beverage emulsions prepared with the different concentrations of XG (0.05%,w/w, ;0.1%,w/w,?;0.15%,w/w, )and the same contents of WO (=3%,w/w)and GA (=10%,w/w)as a function of storage time.Data points represent means (n =3)±standard deviations.Some error bars lie within the data points.

of isooctane according to the method CD 18-90of the AOCS (1998).The total oxidation (Totox)value was determined from following equation:

Totox value =2(peroxide value)+anisidine value

2.6.Experimental design and statistical analysis

The software Design-Expert (trial version 7.1.6,Stat-Ease Inc.,Minneapolis,USA)was used for experimental design,regression analysis of the experimental data and quadratic model building.A central-composite rotatable design (CCRD)was employed to iden-tify the reasonable relationship existing between the response functions and the formulation variables,as well as to determine those conditions that optimized the production of concentrated beverage emulsions based on WO.The in?uence of three main emulsion components namely WO (3–6%,w/w,X 1),GA (5–10%,w/w,X 2),and XG (0.05–0.15%,w/w,X 3)on the lipid oxidation (peroxide value (Y 1),anisidine value (Y 2)and Totox value (Y 3))in model beverage emulsions formulated with WO was studied by using the CCRD.Our preliminary studies showed that the addition of the concentration levels studied to the emulsion formulation resulted in desirable changes of physical and chemical stability of walnut-beverage emulsions.For statistical calculations,the rela-tion between the coded values and actual values are described by Eq.(1):

x i =

X i ?X 0 X

(1)

where x i is the coded value of the variable,X i is the actual value of the variable,X 0is the actual value of X i at the center point,and X is the step change value of the variables.A second-order polynomial regression model was used to express the dependent variables as a function of the independent variables,which is given by Eq.(2):

Y =ˇ0+ˇ1X 1+ˇ2X 2+ˇ3X 3+ˇ11X 2

1

+ˇ22X 22+ˇ33X 2

3+ˇ12X 1X 2+ˇ13X 1X 3+ˇ23X 2X 3+ε

(2)

where X 1,X 2and X 3represent the levels of the factors according to Table 1and ˇ0,ˇ1,...,ˇ23represent coef?cient estimates with ˇ0having the role of a scaling constant.The adequacy of model was examined accounting for coef?cient of determination (R 2),adjusted-R 2(adj-R 2)and coef?cient of variation (CV).Statistical sig-ni?cance of the terms in the regression equations was checked.The signi?cant terms in the model were found by analysis of variance (ANOVA)for each response.The signi?cances of each of the coef-?cients in the empirical model were selected or rejected based on the p -value.For the graphical analysis of the independent variable interactions,the use of 3D surface plots of the regression mod-els was highly recommended (Myers &Montgomery,2002).Thus,these plots were depicted from the ?tted polynomial equations to explain the interactive effects of the independent variables with the response variable.Subsequently,three additional con?rmation experiments were conducted to verify the validity of the statistical experimental strategies.

3.Results and discussion

3.1.Fitting the response surface models

The experiments were performed according to the CCRD matrix under the de?ned conditions and the responses obtained from the experimental runs are given in Table https://www.sodocs.net/doc/279596993.html,ing the CCRD,20sets of tests with appropriate combinations of WO concentration (X 1),GA content (X 2)and XG content (X 3)were conducted.The results in Table 2were ?tted to second-order polynomial models by applying multiple regression analysis for three response variables includ-ing peroxide value (Y 1),anisidine value (Y 2)and Totox value (Y 3).As shown in Table 3,the models were highly signi?cant with very low p -values (p <0.0001).Moreover,the “?tness”of the models was investigated through the lack-of-?t test (p >0.05),which indicated the suitability of models to accurately predict the variation (Myers

S.M.T.Gharibzahedi et al./Carbohydrate Polymers87 (2012) 1611–16191615

Fig.2.Response surface plots and contour plots showing the signi?cant(p<0.05)interaction effects on the variation of peroxide value(a and b),anisidine value(c and d) and Totox value(e and f)of WO-in-water beverage emulsion.

1616S.M.T.Gharibzahedi et al./Carbohydrate Polymers87 (2012) 1611–1619 &Montgomery,2002).A measure of the model’s overall perfor-

mance referred to as the coef?cient of determination and denoted

by R2must be considered(Gharibzahedi et al.,2011).The R2were

found to be0.956,0.985and0.988for peroxide value,anisidine

value and Totox value,respectively(Table3).The adjusted R2values

(0.907–0.974)were also indicated the signi?cance of the models.

At the same time,the values of the CV were3.09–6.75%,indicating

high degree of precision and reliability of the experimental values

(Table3).

3.2.Effects of formulation variables on peroxide value

As illustrated in Table3,the linear effect of all independent variables on the emulsions’peroxide value(Y1)was highly signif-icant.The quadratic effect of WO concentration and XG content was signi?cant at the5%and1%level,respectively(Table3). The results also indicated that among the interactions,only the interaction effect of WO with XG was signi?cant(p<0.0001). The individual optimization procedure showed that the optimum content of WO,GA and XG for the minimum peroxide value (Y1=0.908mequiv.O2/kg oil)was around3%(w/w),10%(w/w)and 0.15%(w/w),respectively.

Hydroperoxides are primary oxidation components that have a lower half-life than secondary oxidation components(Fomuso, Corredig,&Akoh,2002).Many researchers believe that the most common reason for oxidative instability is the interaction between lipid hydroperoxides located at the droplet surface and transi-tion metals from the aqueous phase(McClements&Decker,2000; Mei,McClements,&Decker,1998;Paraskevopoulou,Boskou,& Paraskevopoulou,2007).Mancuso,McClements,and Decker(1999) mentioned that iron is the major prooxidant of lipid oxidation in o/w emulsions.XG,due to its ability to chelate metal ions at negatively charged pyruvate sites in the structure,can quench oil peroxidation by inactivation of Fe2+ions present in the emulsion system(Karadjova,Zachariadis,Boskou,&Stratis,1998;Shimada et al.,1992;Sun et al.,2007).Moreover,increasing viscosity in the aqueous phase by adding XG inhibits diffusion of prooxidants such as oxygen,and slows down the movement of oil droplets,hence decreasing the rate of lipid oxidation(Shimada et al.,1992).As Fig.1a shows,the peroxide value of emulsions was signi?cantly decreased by increasing XG content.

The emulsions with high WO contents had higher peroxide values compared to the low-WO emulsions(Fig.2a and b).It may also be due to the high concentrations of unsaturated fatty acids especially mono-unsaturated fatty acids(oleic acid)at higher WO levels(Shahidi&Wanasundara,1998;Waraho,McClements, Decker,2011).Waraho et al.(2011)found that the monounsat-urated fatty acids due to more linear geometry compared to di-and tri-unsaturated fatty acids had more ability to promote lipid oxidation in soybean oil-in-water emulsions.Therefore,the high presence of these fatty acids with more linear molecular struc-ture could permit them easier availability to the interface area of emulsion droplets and followed by increases the lipid oxidation rate in the emulsions.However,Osborn and Akoh(2004)obtained that the emulsions containing10%oil had signi?cantly higher per-oxide values compared to the emulsions with oil content of30%. This discrepancy might be attributed to differences in the molec-ular arrangements of the fatty acids within surfactant micelles (Miyashita,Tateda,&Ota,1994).Therefore,an increase of XG con-tent in range and initial concentration of WO were associated with minimum peroxide value(Fig.2a and b).

Fig.3a–c shows the results of variations during storage in the droplet-size distribution of the emulsions prepared with3%WO and15%XG in various concentrations of GA.A monomodal size distribution with a mean droplet diameter of0.855–0.952?m was observed when concentration of GA emulsi?er was increased to

1

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0.01

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1 day

7 day

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a

b

c

Fig.3.Change in the droplet-size distribution of the emulsions prepared with3% (w/w)WO and15%(w/w)XG in different concentrations of GA(a,5%,w/w;b,7.5%, w/w;c,10%,w/w)during30days’storage at25±2?C.

10%(w/w).Some of researchers have determined that lipid oxi-dation spreads faster in emulsions with small droplets than in emulsions with large droplets(McClements&Decker,2000;Osborn &Akoh,2004).Since the majority of emulsions had no signi?cant difference for the droplet size values(p>0.05),therefore,there is no dependence of the oxidation rate on droplet size.Fomuso et al. (2002)reported similar results in the case of?sh-oil-based struc-tured lipid emulsions.It is possible that emulsi?er content,rather than droplet size distribution,caused the changes in oxidation char-acteristics found in that study.

The results of the present study showed that high contents of GA not only protect the emulsion droplets against coalescence(Fig.4), but also act as an ef?cient barrier to the penetration and diffusion of prooxidants at the o/w interface,inhibiting lipid oxidation into the droplets(Table3).These?ndings were generally in agreement with those reported by Coupland and McClements(1996)and Silvestre, Chaiyasit,Brannan,McClements,and Decker(2000).Matsumura, Satake,Egami,and Mori(2000)and Matsumura et al.(2003)also

S.M.T.Gharibzahedi et al./Carbohydrate Polymers87 (2012) 1611–1619

1617

Fig.4.Microstructure of WO-in-water beverage emulsions containing low(5%,w/w;(a)fresh emulsion and(c)after30days’storage)and high(10%,w/w;(b)fresh emulsion and(d)after30days’storage)concentrations of GA with3%(w/w)WO and15%(w/w)XG.

demonstrated the antioxidative effect of GA on lipid oxidation in methyl linoleate or methyl oleate emulsions containing?-casein or other surfactants such as Tween20.The inhibitory effect of GA on lipid oxidation in oil-in-water emulsions can probably be attributed to the presence of peptide moieties in its structure(Matsumura et al.,2003).In other words,the radical-scavenging activity of GA found in this study was due to the physical protection of lipids from the lipoxygenase enzyme and radical by the adsorption of GA molecules to the oil-droplet surface(Matsumura et al.,2000).

3.3.Effects of formulation variables on anisidine value

Anisidine value is an indicator used to determine the secondary reaction products during lipid oxidation by evaluating the level of2-alkenals in the oil(White,1995).Secondary oxidation prod-ucts are responsible for the quality and sensory characteristics of oxidized oils(Osborn&Akoh,2004).

The optimization results showed that WO concentration,XG content and GA content had signi?cant(p<0.0001)linear effects on the anisidine value of walnut-beverage emulsions(Table3). The quadratic terms of WO and XG concentrations were signi?cant (p<0.01;p<0.0001).The interaction between GA concentration and XG content was also found to be signi?cant(p=0.0001).The most signi?cant(p<0.05)effect on anisidine value was revealed to be the linear effect of XG followed by the linear term of GA and quadratic effect of XG(Table3).As shown in Fig.2c and d,the variation in the anisidine value of the walnut-beverage emulsion could be explained as a nonlinear function of the XG and GA.The highest concentrations of GA and XG were predicted to achieve the minimum anisidine values(Fig.2c and d).

Analysis of anisidine values showed that the emulsions formu-lated with0.10and0.15%XG presented better protection against lipid oxidation than those formulated with0.05%XG(Fig.1b), which was in agreement with the results for peroxide values.This may be due to the fact that adding XG to the emulsion may,by increasing the viscosity of the aqueous phase,enhance the adsorp-tion of the constituent protein of GA on the oil droplets and slow the diffusion of prooxidants to oil droplet surface,thus decreasing the decomposition of lipid hydroperoxides into secondary prod-ucts(Shimada et al.,1992;Sun&Gunasekaran,2009;Sun et al., 2007).Sun et al.(2007)also reported that the anisidine value of whey protein isolate oil-in-water emulsions stabilized by adding

1618S.M.T.Gharibzahedi et al./Carbohydrate Polymers87 (2012) 1611–1619

Table4

Optimum conditions of formulation variables and,predicted and experimental values of the responses at these conditions.

Independent variables Optimum condition Response variables Optimum condition

Experimental a Predicted

WO concentration3%(w/w)Peroxide value0.978±0.1540.923(mequiv.O2/kg oil) GA content10%(w/w)Anisidine value0.522±0.0360.500

XG content0.12%(w/w)Totox value 2.321±0.121 2.347

a Mean±standard deviation(n=3).

about0.15%XG changed negligibly during storage time.The indi-vidual optimum condition also indicated that minimum anisidine value would be obtained for a walnut-beverage emulsion contain-ing3.03%(w/w)WO,10%(w/w)GA and0.12%(w/w)XG.

3.4.Effects of formulation variables on Totox value

The Totox value is an evaluation of both primary and secondary oxidation products.This value is often considered practical for esti-mating the extent of oxidative deterioration of food lipids,as it combines evidence about an oil’s past history with its present state (Sun,Wang,Chen,&Li,2011).Fig.1c con?rms that the Totox values of extracted WO from prepared emulsions had the same trend as the peroxide and anisidine values.In general,lower Totox values in the emulsions prepared using high concentrations of XG may be due to its higher hydrogen-donating ability and its ef?ciency in less-ening the oxygen consumption at the interfacial surface between oil and water(Kishk&Al-Sayed,2007).

As can be seen in Table3,the linear effect of WO exhibited a signi?cant(p<0.0001)positive effect on the Totox value(Y3);in contrast,the variation of Totox value was negatively in?uenced by the concentrations of GA and XG(p<0.0001).The quadratic term of XG content was signi?cant(p<0.0001).The mutual interaction of GA content with XG concentration was also signi?cant(p<0.001). Fig.2e and f shows the interaction between GA and XG contents. When GA concentration was increased from5to10%(w/w),the Totox value decreased in a parabolic manner.The XG concentration revealed a nonlinear decrease for the emulsion’s Totox value.The results suggested that a walnut-beverage emulsion containing3% (w/w)WO,10%(w/w)GA and0.12%(w/w)XG would result in the minimum Totox value(Y3=2.347).

3.5.Optimization and validation of RSM results

The optimal values of the selected variables were obtained by solving the regression equations using Design-Expert software. According to the RSM analysis,the minimum oxidative stability can be achieved at a WO concentration of3%(w/w),GA content of10% (w/w),and XG content of0.12%(w/w).This optimum condition pro-vides the lowest value of peroxide value=0.923mequiv.O2/kg oil, anisidine value=0.500and Totox value=2.347(Table4).In order to validate the optimization results,three additional experiments were carried out at the optimum conditions within the experi-mental range obtained above(Table4).No signi?cant difference (p>0.05)was found between the experimental and predicted val-ues,which indicates the high accuracy of the presented models. 4.Conclusion

This study used RSM to determine the optimal formulation of WO-in-water beverage emulsions to maximize oxidative stabil-ity.The effects of various levels of WO,GA and XG on the lipid oxidation of walnut-beverage emulsions were studied by central rotatable composite design(CCRD).The results showed that the second-order polynomial models with high R2(>0.95)can be used to predict the optimal formulation for any given conditions within the experimental range.An increase of GA and XG contents in range and initial concentration of WO were associated with high oxidative stability in the emulsions.

Acknowledgments

This study has been partially supported by a grant provided by the Council for Research at the Campus of Agriculture and Natural Resources of the University of Tehran and the Research Council of the University of Tehran.Gratitude is expressed to the ZamZam Iran Co.(Tehran,Iran)for providing the laboratory facilities and ?nancial assistance.Also,the authors gratefully thank Mr Seyed Jalil Gholami and Mrs Mehrnoosh Farid,Department of Fisheries and Environmental Sciences of University of Tehran,for assistance in carrying out the optical microscopic analysis.

References

AOCS.(1998).p-Anisidine value,of?cial method Cd18-90.In D.Firestone(Ed.),Of?-cial methods and recommended practices of the American Oil Chemists’Society.

Champaign,USA:AOCS Press.

Buffo,R.A.,Reineccius,G.A.&Oehlert,G.W.(2001).Factors affecting the emul-sifying and rheological properties of gum acacia in beverage emulsions.Food Hydrocolloids,15,53–66.

Coupland,J.N.&McClements,D.J.(1996).Lipid oxidation in food emulsions.Trends Food Science and Technology,7,83–91.

Donnelly,J.L.,Decker,E.A.&McClements,D.J.(1998).Iron-catalyzed oxidation of menhaden oil as affected by emulsi?ers.Journal of Food Science,63,997–1000. Duh,P.D.,Yen,W.J.&Yen,G.C.(1999).Oxidative stability of polyunsaturated fatty acids and soybean oil in an aqueous solution with emulsi?ers.Journal of the American Oil Chemists Society,76(2),201–204.

Fomuso,L.B.,Corredig,M.&Akoh,C.C.(2002).Effect of emulsi?er on oxidation properties of?sh oil-based structured lipid emulsions.Journal of Agricultural and Food Chemistry,50,2957–2961.

Frankel,E.N.,Satue-Gracia,T.,Meyer,A.S.&German,B.(2002).Oxidative stability of?sh and algae oils containing long-chain polyunsaturated fatty acids in bulk and in oil-in-water emulsions.Journal of Agricultural and Food Chemistry,50, 2094–2099.

Gharibzahedi,S.M.T.,Mousavi,S.M.,Hamedi,M.&Khodaiyan,F.(2011).Determi-nation and characterization of kernel biochemical composition and functional compounds of Persian walnut oil.Journal of Food Science and Technology, doi:10.1007/s13197-011-0481-2

Gharibzahedi,S.M.T.,Mousavi,S.M.,Hamedi,M.&Ghasemlou,M.(2012).Response surface modeling for optimization of formulation variables and physical stability assessment of walnut oil-in-water beverage emulsions.Food Hydrocolloids,26, 293–301.doi:10.1016/j.foodhyd.2011.06.006

Huang,X.,Kakuda,Y.&Cui,W.(2001).Hydrocolloids in emulsions:Particle size distribution and interfacial activity.Food Hydrocolloids,15,533–542. Karadjova,I.,Zachariadis,G.,Boskou,G.&Stratis,J.(1998).Electrothermal atomic adsorption spectrometric determination of aluminium,cadmium,chromium, copper,iron,manganese,nickel and lead in olive oil.Journal of Analytical Atomic Spectrometry,13(3),201–204.

Kishk,Y.F.M&Al-Sayed,H.M.A.(2007).Free-radical scavenging and antioxidative activities of some polysaccharides in emulsions.LWT-Food Science and Technol-ogy,40,270–277.

Koocheki,A.,Kadkhodaee,R.,Mortazavi,S.A.,Shahidi,F.&Taherian,A.R.(2009).

In?uence of Alyssum homolocarpum seed gum on the stability and?ow proper-ties of O/W emulsion prepared by high intensity ultrasound.Food Hydrocolloids, 23,2416–2424.

Krstonoˇs i′c,V.,Doki′c,L.,Doki′c,P.&Dapˇc evi′c,T.(2009).Effects of xanthan gum on physicochemical properties and stability of corn oil in-water emulsions sta-bilized by polyoxyethylene(20)sorbitan monooleate.Food Hydrocolloids,23, 2212–2218.

Mancuso,J.R.,McClements,D.J.&Decker,E.A.(1999).The effects of surfactant type, pH,and chelators on the oxidation of salmon oil-in-water emulsions.Journal of Agricultural and Food Chemistry,47(10),4112–4116.

S.M.T.Gharibzahedi et al./Carbohydrate Polymers87 (2012) 1611–16191619

Matsumura,Y.,Satake,C.,Egami,M.&Mori,T.(2000).Interaction of gum arabic, maltodextrin and pullulan with lipids in emulsions.Bioscience Biotechnology and Biochemistry,64(9),1827–1835.

Matsumura,Y.,Egami,M.,Satake,C.,Maeda,Y.,Takahashi,T.,Nakamura,A.,et al.

(2003).Inhibitory effects of peptide-bound polysaccharides on lipid oxidation in emulsions.Food Chemistry,83(1),107–119.

McClements,D.J.&Decker,E.A.(2000).Lipid oxidation in oil-in-water emulsions: Impact of molecular environment on chemical reactions in heterogeneous food systems.Journal of Food Science,65,1270–1282.

Mei,L.Y.,McClements,D.J.&Decker,E.A.(1998).Iron-catalyzed lipid oxida-tion in emulsion as affected by surfactant,pH and NaCl.Food Chemistry,61(3), 307–312.

Miraliakbari,H.&Shahidi,F.(2008).Antioxidant activity of minor components of tree nut oils.Food Chemistry,111,421–427.

Mirhosseini,H.,Tan,C.P.,Hamid,N.S.A.&Yusof,S.(2008).Optimization the con-tents of Arabic gum,xanthan gum and orange oil affecting turbidity,average particle size,polydispersity index and density in orange beverage emulsion.

Food Hydrocolloids,22(7),1212–1223.

Mirhosseini,H.,Tan,C.P.,Hamid,N.S.A.,Yusof,S.&Chern,B.H.(2009).Character-ization of the in?uence of main emulsion components on the physicochemical properties of orange beverage emulsion using response surface methodology.

Food Hydrocolloids,23,271–280.

Mirhosseini,H.,Tan,C.P.,Taherian,A.R.&Boo,H.C.(2009).Modeling the physico-chemical properties of orange beverage emulsion as function of main emulsion components using response surface methodology.Carbohydrate Polymers,75, 512–520.

Miyashita,K.,Tateda,T.&Ota,T.(1994).Oxidative stability of free fatty acids mix-tures from soybean,linseed and sardine oils in an aqueous solution.Bioscience Biotechnology and Biochemistry,60,315–318.

Moayedi,A.,Rezaei,K.,Moini,S.&Keshavarz,B.(2011).Chemical compositions of oils from several wild almond species.Journal of the American Oil Chemists Society,88,503–508.

Myers,R.H.&Montgomery,R.C.(2002).Response surface methodology,process and product optimization using design experiment.New York:Wiley.

Osborn,H.T.&Akoh,C.C.(2004).Effect of emulsi?er type,droplet size,and oil con-centration on lipid oxidation in structured lipid-based oil-in-water emulsions.

Food Chemistry,84,451–456.Paraskevopoulou,D.,Boskou,D.&Paraskevopoulou,A.(2007).Oxidative stability of olive oil–lemon juice salad dressings stabilized with polysaccharides.Food Chemistry,101,1197–1204.

Shahidi,F.&Wanasundara,U.N.(1998).Methods of measuring oxidative rancidity of fats and oils.In C.C.Akoh,&D.B.Min(Eds.),Food lipids:Chemistry,nutrition and biotechnology(5th ed.,pp.377–396).New York:Marcel Dekker. Shimada,K.,Fujikawa,K.,Yahara,K.&Nakamura,T.(1992).Antioxidative properties of xanthan on the autoxidation of soybean oil in cyclodextrin emulsion.Journal of Agricultural and Food Chemistry,40(6),945–948.

Silvestre,M.P.C.,Chaiyasit,W.,Brannan,R.G.,McClements,D.J.&Decker,E.A.

(2000).Ability of surfactant headgroup size to alter lipid and antioxidant oxi-dation in oil-in-water emulsions.Journal of Agricultural and Food Chemistry,48, 2057–2061.

Sun,C.&Gunasekaran,S.(2009).Effects of protein concentration and oil-phase vol-ume fraction on the stability and rheology of menhaden oil-in-water emulsions stabilized by whey protein isolate with xanthan gum.Food Hydrocolloids,23, 165–174.

Sun,C.,Gunasekaran,S.&Richards,M.P.(2007).Effect of xanthan gum on physic-ochemical properties of whey protein isolate stabilized oil-in-water emulsions.

Food Hydrocolloids,21,555–564.

Sun,Y.E.,Wang,W.D.,Chen,H.W.&Li,C.(2011).Autoxidation of unsaturated lipids in food emulsion.Critical Reviews in Food Science and Nutrition,51,453–466. Taherian,A.R.,Fustier,P.&Ramaswamy,H.S.(2007).Effects of added weighting agent and xanthan gum on stability and rheological properties of beverage cloud emulsions formulated using modi?ed starch.Journal of Food Process Engineering, 30,204–224.

Tangsuphoom,N.&Coupland,J.N.(2009).Effect of surface-active stabilizers on the surface properties of coconut milk emulsions.Food Hydrocolloids,23,1801–1809. Tiliu,T.&Yang,T.S.(2011).Optimization of emulsi?cation and microencapsulation of evening primrose oil and its oxidative stability during storage by response surface methodology.Journal of Food Quality,34,64–73.

Waraho,T.,McClements,D.J.&Decker,E.A.(2011).Impact of free fatty acid concentration and structure on lipid oxidation in oil-in-water emulsions.Food Chemistry,129(3),854–859.

White,P.J.(1995).Conjugated diene,anisidine value,and carbonyl value analyses.

In K.Warner,&N.A.M.Eskin(Eds.),Methods in assess quality and stability of oils and fat-containing foods(p.159).Champaign,USA:AOCS Press.

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Application and development Of case based reasoning in fixture design Abstract: Based on the case based designing (CBD) methodology, the fixture similarity is in two respects: the function and the structure information. Then, the computer aided fixture design system is created on case based reasoning (CBR),in which the attributes of the main features of workpiece and structure of fixture as case index code are designed for the retrieve of the similar cases, and the structure and hierarchical relation of case library are set up for store. Meanwhile, the algorithm based on the knowledge guided in the retrieve of the similar cases, the strategy of case adapt at ion and case storage in which the case ident if cat ion number is used to distinguish from similar cases are presented. The application of the system in some projects improves the design efficiency and gets a good result . Keywords: case based reasoning ;fixture design; computer aided design(CAD) Fixtures are devices that serve as the purpose of holding the workpiece securely and accurately, and maintaining a consistent relationship with respect to the tools while machining. Because the fixture structure depends on the feature of the product and the status of the process planning in the enterprise, its design is the bottleneck during manufacturing, which restrains to improve the efficiency and leadtime. And fixture design is a complicated process, based on experience that needs comprehensive qualitative knowledge about a number of design issues including workpiece configuration, manufacturing processes involved, and machining environment. This is also a very time consuming work when using traditional CAD tools (such as Unigraphics, CATIA or Pro/E), which are good at performing detailed design tasks, but provide few benefits for taking advantage of the previous design experience and resources, which are precisely the key factors in improving the efficiency. The methodology of case based reasoning (CBR) adapts the solution of a previously solved case to build a solution for a new problem with the following four steps: retrieve, reuse, revise, and retain [1]. This is a more useful method than the use of an expert system to simulate human thought because proposing a similar case and

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中文译文 从新型葡萄籽IH636中提取的低聚原花青素和盐碱酸内的铬对治疗仓鼠的动脉粥样硬化症有良好的作用 摘要:动脉硬化症是大动脉上的一种疾病,患有此病在内部动脉壁上会长有脂肪扁桃体颗粒,这些脂肪颗粒最终会堵塞血液流通。以确认的导致动脉硬化症的危险因素包括:遗传、饮食习惯、生活方式、抽烟、循环流通着的脂质和胆固醇含量以及慢性血管炎症和流通信号。黄酮类化合物和动脉硬化症之间有一定的关系,主要是由于黄酮类化合物具有抗氧化剂类的性质,并且黄酮类化合物还有抑制体内低浓度脂蛋白的氧化作用。美国人普遍存在着血脂醇过高现象,而这正是导致心脏血管疾病的主要危险因素。从葡萄籽中提取的低聚原花青素已被证实具有广泛的化学保护特性和心脏保护特性以免受氧危害。最近的一项研究表明从IH636葡萄籽中提取的低聚原花青素与NBC一起使用能降低血脂醇过高的人体中的胆固醇及低浓度脂蛋白和被氧化的脂蛋白总含量。本实验通过分别给仓鼠单独喂食葡萄籽中的低聚原花青素及和NBC一起服用,证实了低聚原花青素对仓鼠的动脉硬化症有益处。因为当给仓鼠服用含0.2%的胆固醇、10%的椰子油的高血胆脂醇食物时他们就会长有与血胆脂醇过多的人像似的脂脂膜。仓鼠食用10周椰子油后就会长出泡沫细胞这是动脉硬化症早期的生物标志。与椰子油一起服用,当低聚原花青素的浓度为50mg/kg 、100mg/kg时,仓鼠得动脉硬化症的几率分别降低50%及60%。若低聚原花青素与NBC一起使用时患病几率大约降低32%。每一实验组用7~9只仓鼠。无论是单独使用葡萄籽中的低聚原花青素或是与NBC 一起使用都对胆固醇、甘油三酸酯的含量,不仅如此还对氧化性脂质损害有很好的抑制作用。这一点已通过硫酸反应物的形成所证明。这一数据表明葡萄籽提取物低聚原花青素(GSPE)和烟碱酸内的铬(NBC)可以提供良好的健康因子。这是通过降低泡沫细胞的形成从而大幅度改变动脉硬化症的发生率来实现的。 关键词:GSPE NBC 动脉硬化症仓鼠泡沫细胞胆固醇甘油三酸酯硫酸反应物 引言

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外文译文范例

外文资料 Rural Labor Movements in Egypt and Their Impact on the State, 1961-1992 Looney, Robert James Toth's highly informative study of Egypt develops the idea that the tarahil or migrant farm workers in Egypt unexpectedly contributed to the making of Egypt's recent history and in shaping the country's national development. His arguments are developed by first examining the struggles taking place inside the rural regime of accumulation and the methods of control each side employed to regulate conflicts over pay and working conditions. This involves not only describing the workers' way of life, standard of living, and the labor processes in both village agriculture and migrant labor, but also identifying the asymmetric relationships and negotiations involved in mutually defining the effort price formula. Toth demonstrates how initially these institutional relations remained local since direct state intervention was relatively limited before the 1960s. Once the state did step in, however, local conflicts diminished while the struggles between workers and their government acquired greater importance. State policies formulated since 1960 repeatedly altered the equation between labor and capital. Toth then shows that the struggle between the government and those who opposed its regulation then became an important motor force in creating Egypt's recent history. Following a carefully laid out introduction, Chapter 2 describes a composite migrant labor trip to work sites on the perimeter of Egypt's northern Delta region where the author conducted field-work in 1980-82. Here the emphasis is placed on introducing the migrant farm workers, describing the variety of social and economic relationships that keep these laborers at the bottom of Egypt's social pyramid. Chapter 3 examines why poor village farm laborers in Egypt repeatedly take up migrant work. In this section the author demonstrates that rural workers in Egypt are channeled into this occupation by the limitations imposed by seasonal unemployment, debt, gender stereotypes, and the country's economic underdevelopment. Chapter 4 develops the methods by which migrant workers exercise some control over valorization by using "weapons of the weak" and other stealth techniques, which enable them to overcome their hardship and poverty. In general, these early chapters discuss the rural regime of accumulation and the local mode of regulation found in the countryside, bridging both village agriculture and migrant labor camp activities. Toth finds these conditions replicated throughout the Egyptian countryside, both north and south. This general picture provides insights into the myriad of tactics and techniques that

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