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Small Ruminant Research 105 (2012) 186– 192

Contents lists available at SciVerse ScienceDirect

Small Ruminant Research

jou rna l h omepa g e: www.elsev ier .com/ locate /smal l rumres

omposition of caprine whey protein concentrates produced byembrane technology after clarification of cheese whey

eatriz Sanmartín, Olga Díaz, Laura Rodríguez-Turienzo, Angel Cobos ∗

rea de Tecnología de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Ciencias de Lugo, Universidad de Santiago deompostela, 27002 Lugo, Spain

r t i c l e i n f o

rticle history:eceived 20 July 2011eceived in revised form7 November 2011ccepted 23 November 2011vailable online 14 December 2011

eywords:aprine cheese whey

a b s t r a c t

Caprine whey protein concentrates were manufactured by means of clarification by ther-mocalcic precipitation followed through ultrafiltration–diafiltration. The chemical, lipidand protein compositions of these caprine whey protein concentrates were evaluated andcompared with those of the clarification by-products (aggregates) and a commercial bovinewhey protein concentrate.

Caprine whey protein concentrates with high protein content (74%) and low lipid content(6%) were obtained due to the clarification procedure. This pre-treatment increased theash and calcium contents. The protein composition and the proportion of phospholipids

ltrafiltrationlarificationhey protein concentrates

omposition

and the main fatty acids were not influenced by the clarification procedure. The aggre-gates showed a different protein profile with the highest levels of caseinomacropeptideand immunoglobulin G. The caprine whey protein concentrates presented similar proteincomposition, lower content of phospholipids and higher content of saturated fatty acids ofshort chain than those observed in the bovine whey protein concentrate.

. Introduction

One of the most important by-products of the dairyndustry is whey. Cheese-making and casein manufactureroduce high amounts of whey, which can cause importantnvironmental problems. However, whey is rich in pro-eins, lactose, minerals and water-soluble vitamins, so its now considered a valuable product rather than a wasteroduct (Morr and Ha, 1993; Jelen, 2003). Bovine whey issually transformed into whey protein concentrates (WPC,5–85% protein) or whey protein isolates (WPI, ≥90% pro-ein) (Morr and Ha, 1993; Foegeding and Luck, 2003) dueo the high nutritional (Hambraeus, 1992) and functional

Mulvihill, 1992) properties of their proteins.

Whey protein concentrates are mainly obtained fromovine whey proteins (Bordenave-Juchereau et al., 2005).

∗ Corresponding author. Tel.: +34 982 824070; fax: +34 982 285872.E-mail address: angel.cobos@usc.es (A. Cobos).

921-4488/$ – see front matter © 2011 Elsevier B.V. All rights reserved.oi:10.1016/j.smallrumres.2011.11.020

© 2011 Elsevier B.V. All rights reserved.

However, the production of ovine and caprine whey is alsoimportant in some countries, such as Southern Europeancountries. We have studied the composition and functionalproperties of ovine whey protein concentrates produced bymembrane technology after clarification of cheese wheyby means of thermocalcic precipitation (Pereira et al.,2002; Díaz et al., 2004, 2006). Few studies have been con-ducted about caprine cheese whey composition (Casperet al., 1998; Pintado et al., 1999, 2001; Moreno-Indiaset al., 2009). Caprine whey is often discarded (Bordenave-Juchereau et al., 2005) and sometimes, it is not acceptedby many whey processors. There is a lack of knowledgeabout caprine cheese whey transformation and the com-position and functional properties of caprine whey proteinconcentrates (Casper et al., 1998). In recent years, there hasalso been a renewed interest in goats’ dairy products as an

alternative dairy product source for people with cows’ milkintolerance (Tziboula-Clarke, 2003).

The objective of this work was to evaluate the effectsof the clarification by thermocalcic precipitation on the

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B. Sanmartín et al. / Small Rum

chemical, lipid and protein compositions of caprine wheyprotein concentrates produced by ultrafiltration followedby diafiltration. These compositions were compared withthose of the clarification by-products (aggregates) andthose of a commercial bovine whey protein concentrate.

2. Materials and methods

2.1. Sample preparation

Sweet caprine whey was obtained from a local cheese-making farm.Caprine whey was obtained from a rennet-coagulated cheese that hadbeen produced from pasteurized whole milk. Briefly, the following cheesetechnology was used on farm. Goat milk was pasteurized (72 ◦C for 30 s)and after the milk was cooled at 34–36 ◦C, starter culture and CaCl2 wereadded. After 5 min, coagulation was performed with commercial rennet(70% chymosin, 30% pepsin). After 25 to 30 min, curds were cut with1 cm wire knives. After the collection, the whey was clarified througha filter (20 �m of pore diameter) and pasteurized at 63 ◦C for 30 min.Approximately 80 L of whey were used in each trial. Thirty litres wereprocessed through ultrafiltration–diafiltration (UF/DF), and 50 L, afterdetermining the calcium content by a colorimetric method using a com-mercial kit (Spinreact S.A., Girona, Spain), were used for thermocalcicprecipitation–separation of aggregates followed by UF/DF. An overviewof the successive steps is shown in Fig. 1. Thermocalcic precipitation wascarried out by the method of Fauquant et al. (1985): the calcium con-tent of the whey was adjusted to 1.2 g/L with CaCl2, the pH adjusted to7.3–7.5 with NaOH 10 N and the temperature was quickly raised to 50 ◦Cand maintained at this value for 8 min. The whey was cooled to 5 ◦C andkept overnight. The next day, the aggregates were separated by centrifu-gation (4 ◦C, 1600 × g, 10 min). The final volume of aggregates was 20%of the initial volume of the whey [volume concentration factor (VCF) = 5].The clarified whey (40 L) and the initial whey (30 L) were submitted toUF and DF using a Centramate lab tangencial flow system equipped withan Omega (polyethersulfone) membrane cassette (0.09 m2 surface area,10 kDa MW cut-off) (Pall Corporation, Ann Arbor, MI, USA). A ten-foldvolumetric concentration factor (VCF = 10) of the retentate was applied.Subsequently, the ultrafiltration retentates were diafiltrated by additionof deionized water followed by concentration (VCF = 10) in order to pro-duce the final diafiltration retentates. The diafiltration retentates and theaggregates were freeze dried in a Lyph-LockTM (Labconco Corporation,Kansas City, USA) freeze dryer for compositional analysis. Three productswere obtained: the aggregate powder (aggregates), the diafiltration reten-tate powder from the clarified whey (CWP) and the diafiltration retentatepowder from the unclarified whey (UWP). All experiments were made intriplicate.

2.2. Chemical composition

The chemical compositions of the original cheese whey, the three kindof caprine products (aggregates, CWP and UWP) and a commercial bovineWPC (BWPC) [Protarmor 800, Armor Proteins (Saint Brices en Coglés,France)] were determined as follows: dry matter by oven drying at 105 ◦Cuntil constant weight (A.O.A.C., 2005), ash by incineration at 550 ◦C for6 h (A.O.A.C., 2005); protein by the Kjeldahl method using a conversionfactor of 6.38 and by the Bradford method (Kruger, 1996); lipids by theRöse-Gottlieb method (A.O.A.C., 2005); lactose by difference [dry matter –(protein + ash + lipids)] and calcium and lactates by colorimetric methodsusing commercial kits (Spinreact S.A., Girona, Spain). All determinationswere made in duplicate.

2.3. Protein composition

The determination of the main whey proteins (�-lactoglobulin,�-lactalbumin, serum albumin and immunoglobulin) and the caseino-macropeptide of whey and powders were simultaneously carried outby reversed-phase HPLC, following the method of Elgar et al. (2000).Reagents were HPLC grade. Commercially purified whey protein and

caseinomacropeptide standards were purchased from Sigma Chemical(St. Louis, USA). Samples of powders (CWP, UWP and bovine WPC) andaggregates were dissolved (3% and 10%, w/v of protein, respectively) inMilli-Q water (Millipore Ibérica S.A., Madrid, Spain), whereas the wheywas diluted twofold with Milli-Q water. Before RP-HPLC analysis, all

esearch 105 (2012) 186– 192 187

the samples and standards were filtered through filters (0.45 �m ofpore diameter) to remove any insoluble material. The sample injectionvolume was 100 �l. Mixed calibration standards with different concen-trations were prepared in order to construct the standard curves. Proteinsand caseinomacropeptide were chromatographed with a Source 15RPCST 4.6/100 column (Amersham Biosciences, Uppsala, Sweden) at roomtemperature at a flow-rate of 1 ml/min using a Shimadzu liquid chro-matograph composed by pump model LC-10AT, a low pressure gradientflow control valve model FCV-10ALVP and a spectrophotometric detectormodel SPD-10AV. System control and peak integration was carried outusing LC Solution software (Shimadzu Corp., Kyoto, Japan). The columnwas equilibrated with 80% eluent A [0.1%, v/v trifluoroacetic acid (TFA)in Milli-Q water] and after sample injection a 1-min isocratic period wasapplied followed by a series of linear gradients from 20% to 100% sol-vent B (0.09%, v/v TFA in 90%, v/v acetonitrile and 10% Milli-Q water)as follows: 1–6 min, 20–40%; 6–16 min; 40–45%; 16–19 min; 45–50%;19–20 min, 50%; 20–23 min, 50–70%; 23–24 min, 70–100%. The columnwas re-equilibrated after a 5-min hold at 100% B by a 5-min linear gradientto 20% B followed by an isocratic period of 8 min. The detection was carriedout at 214 nm. Quantification was based on peak areas of whey proteinsand caseinomacropeptide, and external standards for each compound.The results were expressed in g/100 g of protein. All determinations weremade in triplicate.

2.4. Lipid and fatty acid composition

In order to study the fatty acid composition and the composition ofthe lipids of the powders (CWP, UWP, aggregates and BWPC), the extrac-tion of the lipids was necessary. The lipid extraction was carried outby the method of Bligh and Dyer (Hanson and Olley, 1963). The fattyacid composition of lipids was determined by gas liquid chromatog-raphy of methyl esters prepared in basic conditions (KOH:methanol).The gas chromatograph was a Hewlett–Packard apparatus (model 5890;Hewlett Packard Co., Wilmington, DE, USA) equipped with a dual flameionization detector. The capillary column (30 m, internal diameter0.25 mm) was packed with OV-225 (0.1 �m) on fused silica. The anal-ysis was performed using an initial isothermic period (150 ◦C, 2 min);thereafter the temperature was incremented to 210 ◦C at an increas-ing rate of 4 ◦C/min, and finally an isothermic period (210 ◦C, 15 min)was established. The injector and detector were maintained at 250 ◦C. AHewlett–Packard HP3394A integrator (Hewlett Packard Co., Wilmington,DE, USA) was used for quantitative analyses. The identification of differ-ent fatty acid methyl esters was performed by comparing the retentiontimes with those of authentic standards (Sigma Chemical, St. Louis,USA). The amounts of fatty acids were expressed as a percent of totalarea of injected methyl esters. All the analyses were performed intriplicate.

Total lipids (100 mg) were separated into neutral lipids, free fatty acidsand phospholipids in NH2-aminopropyl minicolumns by the method ofKaluzny et al. (1985). The neutral lipid fraction is mainly composed ofglycerides and this term will be used throughout the text. Amounts ofglycerides, phospholipids and free fatty acids were quantified by weighing(Vaghela and Kilara, 1995) and the results were expressed as a percent ofthe total weight obtained.

2.5. Statistical analysis

The data from caprine powders were analysed by a one-way ANOVA,and the means were compared using the least significant difference test(LSD) with significance at p ≤ 0.05 (SPSS version 12.0 for Windows, 2004,SPSS Inc., Chicago, IL, USA).

3. Results and discussion

3.1. Chemical composition of caprine cheese whey

Chemical composition and pH of caprine whey are

shown in Table 1. The pH value corresponded to sweetwhey (the casein was coagulated by rennet) and was sim-ilar to that found by Casper et al. (1998) in caprine sweetwhey.

188 B. Sanmartín et al. / Small Ruminant Research 105 (2012) 186– 192

Whey

Pasteurized whey 80 L

Centrifugation VCF=5

Ultrafiltration ( 10 kDa ) VCF=10

Retentate 3 L

Filtrate 27 L

Freeze drying

Agreggates 10 L

Clarified whey 40 L

Thermocalcic precipitation

Pasteurization

36 L H2O

27 L H2O

Diafiltration VCF=10

Ultrafiltration ( 10 kDa ) VCF=10

Freeze drying

Filtrate 36 L

Filtrate 36 L

Filtrate 27 L

Retentate 4 L

Retentate 3 L

Diafiltration VCF=10

Freeze drying

Retentate 4 L

UWP

CWP

Aggregates

F diafiltrar

shPe

r

TCo

M

ig. 1. Processing diagram for making aggregate powders (aggregates),etentate powder from the unclarified whey (UWP).

The dry matter content of the caprine whey (7.07%) wasimilar to that reported by Moreno-Indias et al. (2009),igher than that observed by Casper et al. (1998) andintado et al. (2001) and lower than that found by Pintado

t al. (1999).

Lipid concentration (0.84%) was higher than thoseeported by Casper et al. (1998), Moreno-Indias et al. (2009)

able 1hemical composition (%), pH and protein composition (g/100 g protein)f caprine cheese whey.

Caprine cheese whey

Dry matter 7.07 ± 0.09Lipids 0.84 ± 0.18Protein 0.63 ± 0.03Ash 0.57 ± 0.01Lactose 5.02 ± 0.24Calcium 0.04 ± 0.01Lactates 0.14 ± 0.06pH 6.34 ± 0.29�-Lactoglobulin 52.02 ± 2.05Caseinomacropeptide 21.75 ± 0.53�-Lactalbumin 11.96 ± 1.05Immunoglobulin G 9.49 ± 1.47Serum albumin 4.79 ± 0.33

ean values ± standard deviation (n = 3).

tion retentate powder from the clarified whey (CWP) and diafiltration

and Pintado et al. (2001) in caprine whey. This differencemight be due to the lack of whey skimming in our work.Besides, the cheese whey produced in cheese factories hadlower lipid contents than that obtained in cheese-makingfarms due to the fact that the technology used in factories(automatic control of the temperature and curd particlesize) improves curd fat recovery (Moreno-Indias et al.,2009).

The protein content (0.63%) was lower than the val-ues observed in other caprine whey (Casper et al., 1998;Moreno-Indias et al., 2009; Pintado et al., 1999, 2001) andhigher than those reported in the acid caprine whey ofCasper et al. (1998). Protein contents are influenced bybreed, stage of lactation, feeding, season, etc (Park et al.,2007). In our work, the caprine cheese was manufacturedwith milk from Alpine and Saanen goats and the milk ofthese breeds has a low protein content (Tziboula-Clarke,2003).

The ash content (0.57%) was similar to that observedin sweet caprine whey but lower to that reported in acidcaprine whey by Casper et al. (1998). The mineral content

of acid whey is higher than sweet whey due to solubi-lization of colloidal calcium phosphate of casein micellesthat occurs concomitantly with acidification (Pintado et al.,2001; Jelen, 2003). The content of CaCl2 added during

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B. Sanmartín et al. / Small Rum

cheese making also affects the calcium content. The con-tent of this mineral is very important for the functionalityof whey proteins, because it plays a critical role in the inter-actions between proteins (Johansen et al., 2002).

3.2. Protein composition of caprine cheese whey

The protein composition (expressed as g/100 g protein)of the caprine cheese whey is showed in Table 1. The mainprotein was �-lactoglobulin (�-LG) (50% of total whey pro-tein) followed by caseinomacropeptide (CMP) (21.75%),�-lactalbumin (�-LA) (11.96%), immunoglobulin G (IgG)(9.49%) and seroalbumin (SA) (4.79%).

The concentrations of �-LG and �-LA were lower thanthose observed in sweet (Casper et al., 1998) and acidcaprine whey (Law and Brown, 1994; Casper et al., 1998).These differences were probably due to the CMP was notdetermined by these researchers. However, this is one ofthe most important protein fractions of sweet whey thatderived from the action of chymosin on к-casein during themilk clotting process in cheesemaking (Park et al., 2007).The CMP constitutes approximately 20% of the protein frac-tion of sweet whey (Jelen, 2003).

3.3. Chemical composition of powders

Table 2 shows the chemical composition of powdersobtained from caprine cheese whey and the bovine WPC.Significant differences were observed among caprine pow-ders for ash, lipid, protein and calcium, whereas dry matterand lactates did not differ significantly.

The dry matter contents of the caprine powders werehigher than 95%. The protein content of the clarified pow-ders (74.14%) was higher than those of unclarified andaggregates powders (36.84 and 9.35%, respectively). Theamount of lipids decreased from 53.18% in unclarified pow-ders to 5.91% in clarified powders; the lipid content ofaggregates was 34.60%.

These results clearly indicate that the clarification pro-cedure improves the protein content and reduces the lipidcontent of the powders. During thermocalcic precipita-tion, insoluble complex between calcium and lipoproteinsare formed (Vaghela and Kilara, 1996), which are retainedin aggregates. Despite the fact that the whey was notskimmed, the great reduction of the lipid level is correlatedwith this clarification.

The levels of ash were much higher in aggregates(10.72%) than those in clarified and unclarified WPC (1.15%and 0.65%). The lactose and calcium content were higher inaggregates (40.46% and 2.64%) than in clarified and unclar-ified powders (14.19% and 0.56% for lactose and 6.89% and0.18% for calcium). The high level of calcium in aggregatesis probably related with the thermocalcic precipitation,because most of the calcium added during this clarificationcan be retained with lipoproteins (Maubois et al., 1987).

The information on the chemical composition of caprinewhey protein concentrates is very limited. Casper et al.

(1999) obtained caprine whey protein concentrates pre-pared by ultrafiltration–diafiltration, with a content of66.7% of protein, 26.0% of lactose, 3.6% of ash and 0.3% offat. The caprine WPC obtained by these authors showed

esearch 105 (2012) 186– 192 189

higher ash and lactose content, but lower lipid content(due to skimming of the liquid whey) than our caprineWPC. Pintado et al. (1999) studied caprine WPC prepared bydialysis and found that its composition was 63.4% protein,17.0% lactose and 4.3% ash; they also obtained a caprineWPC with more lactose and ash than our caprine WPC. Theclarification procedure produced a CWP with higher lev-els of protein than those observed by Casper et al. (1999)and Pintado et al. (1999). The lipid and protein contents ofBWPC were similar and ash content was higher than thoseobserved in CWP.

3.4. Protein composition of powders

Table 3 shows the protein composition (�-LG, CMP,�-LA, IgG and SA) of caprine cheese whey powders andbovine WPC. No significant differences between the pro-tein composition from CWP and UWP were observed. Theproportion of the different proteins in BWPC was also verysimilar. �-LG was the main protein (60–63%), followed byCMP (12–13%), �-LA (11–12%), and IgG (9–11%). SA (seroal-bumin) showed the lowest percentages (3–4%).

Caprine WPC (CWP and UWP) showed lower �-LA andmore SA and IgG contents than those observed by Casperet al. (1999) and Pintado et al. (1999) also in caprine WPC.The content of �-LG was higher than that reported byPintado et al. (1999) and lower than that observed byCasper et al. (1999).

The aggregates showed a different protein profiles. The�-LG and the CMP were the main proteins, which presenteda similar content (31–33%) followed by the IgG (18.9%), the�-LA (11.5%) and the SA (6.1%). Significant differences in�-LG, CMP, IgG and SA contents from caprine WPC andaggregates were observed.

When comparing the protein profile of the sweet wheyand the different caprine powders, many differences wereobserved. Both WPC (CWP and UWP) showed higher pro-portion of �-LG and lower CMP than sweet whey; whilethe aggregates had higher values of CMP, SA and IgG andlower values of �-LG in relation to sweet whey. The high-est values of CMP in aggregates indicate that CMP could beretentated with lipoproteins during clarification. The low-est values of CMP in caprine WPC could also indicate thatthis protein had been filtrated during UF/DF. It has been alsosuggested (Casper et al., 1999; De la Fuente et al., 2002)that �-LA could pass through the membrane during UF.However, similar concentrations of �-LA were observed inliquid sweet whey and caprine powders. The aggregatesshowed the highest content of IgG. This increase of IgGmight be mainly due to the removal of IgG by precipitationat pH 7 during clarification; this protein has the isoelectricpoint at pH 7 (Musale and Kulkarni, 1998).

3.5. Lipid composition of powders

Table 4 shows the lipid composition (expressed as% of total lipids) of caprine cheese whey powders and

bovine WPC. Glycerides represented 86–91%, phospho-lipids 5.3–7.0% and free fatty acids 3.1–6.7% of the totallipid content in caprine powders. Significant differencesin the lipid composition between CWP and the other two

190 B. Sanmartín et al. / Small Ruminant Research 105 (2012) 186– 192

Table 2Chemical composition (%) of caprine cheese whey powders and bovine whey protein concentrate.

% CWP UWP Aggregates Bovine WPC

Dry matter 95.38 ± 1.13 97.56 ± 0.68 95.12 ± 1.23 92.67Ash 1.15 ± 0.10b 0.65 ± 0.27b 10.72 ± 1.23a 3.39Lipids 5.91 ± 3.08c 53.18 ± ± 6.34a 34.60 ± 4.64b 4.32Protein 74.14 ± 3.37a 36.84 ± 4.92b 9.35 ± 0.91c 74.74Lactose 14.19 ± 1.50b 6.89 ± 0.81c 40.46 ± 2.37a 10.22Calcium 0.56 ± 0.06b 0.18 ± 0.16b 2.64 ± 0.72a 0.39

± 0.77

C tes, aggw 05). Me

cchiwtope

TP

Cw

TL

Cup

Lactates 3.27 ± 0.70 3.23

WP, clarified whey powders; UWP, unclarified whey powders; Aggregaithin the same row with different superscripts differ significantly (p < 0.

aprine powders (UWP and aggregates) were observed. Thelarified powders showed lower content of glycerides andigher content of free fatty acids than those of unclar-

fied powders and aggregates. No significant differencesere observed in the proportion of phospholipids among

he three caprine powders. Maubois et al. (1987) the-rized that the aggregates obtained with thermocalcicrecipitation contained most of the phospholipids. How-ver, the content of phospholipids was not reduced by the

able 3rotein composition (g/100 g powder) of caprine cheese whey powders and bovin

CWP UWP

�-Lactoglobulin 60.28 ± 2.45a 63.57Caseinomacropeptide 12.24 ± 4.11b 12.90�-Lactalbumin 12.53 ± ± 0.36 11.18Immunoglobulin G 10.75 ± 1.79b 9.02Serum albumin 4.21 ± 1.03b 3.34

WP, clarified whey powders; UWP, unclarified whey powders; Aggregates, aggithin the same row with different superscripts differ significantly (p < 0.05). Me

able 4ipid composition (% lipids) and fatty acid profiles (% of total fatty acids) of caprin

CWP UWP

Glycerides 86.22 ± 1.09b 90.83 ± 1Phospholipids 7.01 ± 0.65 5.45 ± 0Free fatty acids 6.76 ± 0.82a 3.71 ± 2C-4:0 1.59 ± 0.17b 2.02 ± 0C-6:0 1.82 ± 0.58 2.25 ± 0C-8:0 2.41 ± 0.37b 2.89 ± 0C-9:0 0.02 ± 0.00 0.04 ± 0C-10:0 10.67 ± 0.46 11.64 ± 1C-10:1 0.18 ± 0.09 0.18 ± 0C-11:0 0.06 ± 0.03 0.06 ± 0C-12:0 4.08 ± 0.06b 4.31 ± 0C-13:0 0.07 ± 0.01 0.08 ± 0C-14:0 10.31 ± 1.20 9.73 ± 0C-14:1 0.10 ± ± 0.01b 0.11 ± 0C-15:0 1.24 ± 0.16 1.09 ± 0C-16:0 26.39 ± 1.08 26.49 ± 0C-16:1 0.37 ± 0.02 0.53 ± 0C-17:0 0.69 ± 0.08 0.68 ± 0C-17:1 0.32 ± 0.01 0.30 ± 0C-18:0 11.59 ± 0.89 10.58 ± 1C-18:1 23.80 ± 2.19 24.38 ± 0C-18:2 n-6 3.57 ± 0.89a 1.85 ± 0C-18:3 n-3 0.72 ± 0.14 0.79 ± 0SFA 70.94 ± 1.23 71.86 ± 1MUFA 24.76 ± 2.17 25.51 ± 0PUFA 4.29 ± 1.03a 2.64 ± 0

WP, clarified whey powders; UWP, unclarified whey powders; Aggregates, ages within the same row with different superscripts differ significantly (p < 0.05olyunsaturated fatty acids. Mean values ± standard deviation (n = 3).

3.19 ± 0.60 1.84

regates powders; Bovine WPC, bovine whey protein concentrate. Valuesan values ± standard deviation (n = 3).

thermocalcic precipitation. In bovine whey protein con-centrates, Vaghela and Kilara (1996) also observed thatphospholipids were not selectively removed by the pre-treatment of whey with calcium chloride and contrary tothe hypothesis, they also observed that the pre-treatment

of whey with calcium chloride and heat, followed bycentrifugal clarification, significantly increased the pro-portion of phospholipids and decreased the proportion oftriacylglycerols.

e whey protein concentrate.

Aggregates Bovine WPC

± 7.52a 32.86 ± 3.53b 63.39 ± 6.27b 30.60 ± 1.61a 11.50 ± 2.21 11.51 ± 0.21 11.75

± 1.95b 18.90 ± 1.45a 9.65 ± 1.04b 6.13 ± 0.55a 3.72

regates powders; Bovine WPC, bovine whey protein concentrate. Valuesan values ± standard deviation (n = 3).

e cheese whey powders and bovine whey protein concentrate.

Aggregates Bovine WPC

.72a 91.48 ± 3.35a 79.33

.32 5.39 ± 1.99 16.20

.03b 3.12 ± 1.43b 4.47

.22a 2.09 ± 0.13a 1.14

.24 2.37 ± 0.24 0.86

.13a 2.98 ± 0.02a 0.53

.01 0.03 ± 0.01 0.10

.01 11.10 ± ± 0.30 1.66

.07 0.13 ± 0.03 0.11

.01 0.05 ± ± 0.01 0.05

.08a 4.38 ± 0.07a 2.76

.01 0.07 ± 0.00 0.08

.53 9.91 ± 0.25 10.85

.01a 0.10 ± 0.01b 0.73

.06 1.08 ± 0.03 1.36

.65 27.18 ± 0.67 31.30

.21 0.54 ± 0.19 1.43

.03 0.69 ± 0.03 0.64

.01 0.31 ± 0.05 0.36

.69 11.41 ± 2.23 11.02

.70 22.58 ± 1.92 30.16

.59b 2.21 ± 0.11b 4.22

.10 0.80 ± 0.16 0.66

.27 73.33 ± 1.91 62.34

.84 23.66 ± 2.17 32.78

.57b 3.01 ± 0.26ab 4.88

gregates powders; Bovine WPC, bovine whey protein concentrate. Val-). SFA, saturated fatty acids; MUFA, monounsaturated fatty acids; PUFA,

inant R

B. Sanmartín et al. / Small Rum

The phospholipid content of bovine WPC (16.2%) washigher and the glycerides content (79.3%) was lower thanthose observed in caprine powders. The results in BWPCwere in the range to those observed by Vaghela andKilara (1996) in bovine WPC containing 35 and 75% pro-tein and varying amounts of residual lipids. The freefatty acids content of BWPC (4.5%) was higher than thoseobserved by these authors (1.8–3.5%). No studies aboutlipid composition of caprine WPC were found in theliterature.

The fatty acid profiles (expressed as % of total fattyacids) of caprine cheese whey powders and bovine WPCare shown in Table 4. In caprine powders, the saturatedfatty acids were the most abundant (71–73%) followed bymonounsaturated fatty acids (24–25%). Palmitic (26–27%),oleic (23–24%), stearic (11–12%), capric (11–12%) andmiristic (10%) acids were the main fatty acids. These are alsothe main fatty acids found in goat milk (Alonso et al., 1999;Banón et al., 2006; Park, 2006), goat cheese (Lucas et al.,2008) and caprine whey (Moreno-Indias et al., 2009). Inthis sense, Moreno-Indias et al. (2009) reported that cheesemaking procedure did not affect fatty acid compositionduring the transition from milk to cheese whey.

No significant differences in the proportion of themain fatty acids among the three caprine powders wereobserved. Significant differences were found in other fattyacids (C-4:0; C-8:0; C-12:0; C-14:1; C-18:2 n-6) and in thepolyunsaturated fatty acids (PUFA) content. The highestlevels of linoleic acid and PUFA of CWP were probably dueto the highest proportion of phospholipids of this powder;the phospholipids have a higher proportion of PUFA thanglycerides (Walstra et al., 2006).

The caprine powders showed higher content of satu-rated fatty acids of short chain, specifically C-6:0, C-8:0,C-10:0 and C-12:0, than that observed in bovine WPC.Goat milk is characterized by higher contents of these fattyacids than ovine (Jandal, 1996) or bovine (Tziboula-Clarke,2003; Park et al., 2007) milk due to differences in poly-merization of the acetate produced by the rumen bacteriain goats (Tziboula-Clarke, 2003). Besides, the bovine WPCcontained more monounsaturated fatty acids and PUFAthan the caprine powders. The higher content of PUFA inbovine WPC were probably due to this powder showedhigher content of phospholipids.

4. Conclusions

Caprine whey protein concentrates with high pro-tein content (74%) and low lipid content (6%) wereobtained by means of clarification by thermocalcic pre-cipitation followed by ultrafiltration–diafiltration. Thispre-treatment increased the ash and calcium contents. Thephospholipids proportion was not reduced by thermocalcicprecipitation. The protein composition and the propor-tion of the main fatty acids were not influenced by thispretreatment. The clarification procedure increased theproportion of caseinomacropeptide and immunoglobulin

G and decreased the proportion of �-lactoglobulin in theaggregates. The protein composition of caprine whey pro-tein concentrates was similar to the commercial bovineWPC. The caprine products showed a lower content of

esearch 105 (2012) 186– 192 191

phospholipids and higher content of saturated fatty acids ofshort chain than those observed in the bovine WPC. Accord-ing to their composition, caprine WPC could be of interestin the food industry in products that require the use ofnon-bovine proteins.

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