Textural, melting and sensory properties of low-fat fresh kashar ...

ARTICLE IN PRESS

International Dairy Journal 14 (2004) 365–373

Textural, melting and sensory properties of low-fat fresh kashar cheeses produced by using fat replacers Nurcan Koca*, Mustafa Metin Department of Food Engineering, Engineering Faculty, Ege University, Bornova, Izmir 35100, Turkey Received 17 January 2003; accepted 7 August 2003

Abstract The textural, melting and sensory properties of low-fat fresh kashar cheeses (B70% fat reduction) produced by using two proteinbased fat replacers (1.0% w/w SimplessesD-100 and 1.0% w/w Dairy-Lot) and one carbohydrate-based fat replacer (5.0% w/w RaftilinesHP) were examined during the storage period for 90 days. The low-fat cheese without fat replacer and the full-fat cheese were also produced, for comparison. The moisture contents and the values of moisture in non-fat substance of the cheeses made with fat replacers were significantly higher than low fat control cheese, whereas protein contents were significantly lower. The use of fat replacers decreased the hardness, springiness, gumminess and chewiness and increased cohesiveness. SimplessesD-100 corrected all appearance defects determined in low fat cheese. SimplessesD-100 and RaftilinesHP produced an improving effect on flavour, texture and overall acceptability of low-fat cheese until the 30th day of storage. The sensory scores of the cheeses with these fat replacers decreased due to excessive softening and salty flavour for SimplessesD-100 and undesirable colour, softening and off-flavour for RaftilinesHP on the 60th and 90th days of storage. Dairy-Lot had no effect on the textural and sensory properties of low-fat cheese. The use of RaftilinesHP among fat replacers caused a slight increase in meltability. These results indicated that SimplessesD-100 and RaftilinesHP can improve the texture and sensory properties of low-fat fresh kashar cheese. However, further investigations are needed to prevent the defects which were shown after the 60th day of storage. r 2003 Elsevier Ltd. All rights reserved. Keywords: Low fat kashar cheese; Fat replacer; Texture; Sensory properties

1. Introduction Kashar cheese is a semi-hard Turkish traditional cheese which is one of the cheeses consumed most in Turkey. According to Turkish Standards, this cheese is classified as ‘‘fresh kashar cheese’’ and ‘‘old or matured kashar cheese’’ in terms of ripening (Turkish Standards (TS), 1999). In recent years the production of fresh kashar cheese has increased in contrast to matured kashar cheese because of the economical reasons. Because of increasing consumer trend for low fat products, the production of reduced- or low-fat cheeses has significantly increased since 1980 (Molina, Alvarez, Ramos, Olano, & Lopez-Fandino, 2000). However, fat has an important role in the development of flavour, texture and appearance of cheese (Sipahioglu, Alveraz, *Corresponding author. Fax: +90-232-3427592. E-mail address: [email protected] (N. Koca). 0958-6946/$ - see front matter r 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.idairyj.2003.08.006

& Solano-Lopez, 1999). Removal of fat from cheese causes textural, functional and sensory defects such as rubbery texture, lack of flavour, bitterness, off-flavour, poor meltability and undesirable colour (Fife, McMahon, & Oberg, 1996; McMahon, Alleyne, Fife, & Oberg, 1996; Sipahioglu et al., 1999; Mistry, 2001; Romeih, Michaelidou, Biliaderis, & Zerfiridis, 2002). Therefore, several strategies have been proposed in order to improve the flavour and texture of low-fat cheeses. These strategies can be collected in three titles (Drake & Swanson, 1995; Mistry, 2001): making-process modifications; starter culture selection and use of adjunct cultures; use of fat replacers. Fat replacers are ingredients intended to be used in the place of natural fats with the objective of obtaining a reduction in the caloric value (Huyghebaert, Dewettinck, & de Greyt, 1996). They are categorized as fat substitutes which are fat-based and as fat mimetics which are protein- and carbohydrate-based. Fat

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mimetics have often been recommended to be used in cheese products consisting of mainly microparticulated protein- and carbohydrate-based materials (Romeih et al., 2002). These materials are used for improving sensory and functional properties of low-fat cheeses by binding water and by improving texture and yield (Drake, Bolyston, & Swanson, 1996a). Therefore, they give a sense of lubricity and creaminess (Romeih et al., 2002). They, because of their particulate nature, can also act as light scattering centers and increase the opaqueness of low-fat cheese (McMahon et al., 1996). The objective of this study was to determine the effects of SimplessesD-100, Dairy-Lot and RaftilinesHP on the textural, melting and sensory properties of low-fat fresh kashar cheese and also to find the correlation between these properties. The effects of the fat reduction on these properties were also determined.

2. Materials and methods 2.1. Materials The whole cows’ milk and skim cows’ milk were supplied by Pinar Dairy Company. Streptococcus thermophilus E was used as the starter culture (Wiesby GmbH & Co. KG) and b-carotene as the colouring agent (Roche). Fat replacers used were SimplessesD100 (NutraSweet Co.), which is the microparticulated whey protein, supplied by Pinar Dairy Company and Dairy-Lot (Pfizer Inc. Co.), whey protein concentrate, and RaftilinesHP (Orafti), inulin, each supplied by Dora Company in Turkey. 2.2. Cheese production Cheese production was carried out in Dairy Pilot Plant of Food Engineering Department of Ege University. For the production process, observations obtained from dairies were applied to pilot plant scale. Low-fat cheese samples were produced by using 1.0% of SimplessesD-100 (SM), 1.0% of Dairy-Lot (DL) or 5.0% of RaftilinesHP (RF). Full fat (FF) and low-fat (LF) control cheeses without fat replacer were also produced, for comparison. The fat content of milk was standardized to 2.5% for full-fat and 0.6% for low-fat cheese production. 65 kg of standardized milk were used for each batch. Fat replacers were added to cheese milk at 30 C and mixed. After the mixing process, all batches were pasteurised at 65 C for 30 min and then cooled to 34 C. b-carotene (0.7 mg kg1), starter culture (9 mL kg1) and CaCl2 (2 mg kg1) were added. When the pH of milk was at 6.2–6.3, rennet diluted with pure water was added to milk. Cutting was done 50 min later. The curd was cut with a curd knife in the shape of 1 cm3 cubes. The cut curd was allowed to settle for 10 min.

Cooking was done by increasing the temperature within 30 min from 34 C to 40 C. The increase rate was 1 C for every 5 min. At the same time the cheese curd was agitated. At the end of the cooking, 20 kg of whey were drained from each batch. The cheese curd was fermented until it reached 5.2–5.25 pH. The remaining whey was then drained. The curd was hand-stretched in a 6% brine at 72 C for full-fat cheese, at 85 C for low-fat control cheese, at 75 C for low-fat cheese with SimplessesD-100 and at 80 C for low-fat cheeses with Dairy-Lot and RaftilinesHP. They were put into cylindrical plastic moulds and turned 30 min later to provide flat surface. All cheeses were cooled in room temperature and the moulds were removed. After that, the cheeses were allowed to gain their yellow colour for 24 h at 18–20 C. One block of fresh kashar cheese was approximately 400 g. The blocks of cheeses were vacuum and shrink packaged in Cryovac bags and stored at 4– 6 C for 90 days. Cheese samples were taken for chemical analyses on the 7th day and for textural, melting and sensory analyses on the 1st, 7th, 30th, 60th and 90th days of storage. Cheese was manufactured in triplicate for each group. 2.3. Chemical analyses The moisture content of cheese samples was determined by gravimetric method (International Dairy Federation (IDF), 1982), fat content by Van-Gulik method (Turkish Standards (TS), 1978) and total nitrogen content by Kjeldahl method (AOAC, 1995). The protein content of cheeses was calculated by multiplying the total nitrogen content by 6.38 and the moisture in non-fat substance was calculated according to Codex Alimentarius for Milk and Milk Products (Codex Alimentarius (CA), 2000). 2.4. Textural analyses Texture profile analysis (TPA) parameters were determined by using Instron Universal Testing Machine, Model 1140 (Instron Ltd., UK) equipped with a 50– 500 kg load cell. A flat plate probe with 57 mm of diameter was attached to moving crosshead. Cylindrical samples were prepared using a metal borer at 4–6 C and wrapped with plastic stretch cover. Samples were taken at least 1 cm away from cheese surface. They were left at 25 C for almost 30 min until they reached the definite temperature (1971 C). The central temperature of a control specimen was measured by a thermocouple. The dimensions of cheese specimens were 25 mm both in diameter and height. The operating conditions were: crosshead speed 50 mm min1, chart speed 200 mm min1, 80% of compression ratio from the initial height of the sample in two bites. The texture profile parameters were determined using the TPA

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refrigerator at 4 C for 30 min and then horizontally in an oven heated at 104 C for 60 min (Poduval & Mistry, 1999). Meltability was measured as flow distance (mm) of melted cheese. 2.6. Sensory evaluation

Fig. 1. The TPA curve of full-fat fresh kashar cheese (springiness= length2/length1, adhesiveness=A3 ; cohesiveness=A2 =A1 ; gumminess= hardness cohesiveness, chewiness=gumminess springiness).

curve, an example, given in Fig. 1: the compressive force (kg) recorded at maximum compression during the first bite as a measure of cheese hardness (Katsiari, Voutsinas, & Kondyli, 2002); the distance of the detected height of the product on the second compression divided by the original compression distance (length2/length1) as a measure of springiness (Anonymous, 2002); the negative force area (A3, cm2) during the first bite as a measure of adhesiveness (Antoniou, Petrides, Raphaelides, Ben Omar, & Kesteloot, 2000); the ratio of positive area during the second compression to the positive area during the first compression (A2 =A1 ) as a measure of cheese cohesiveness; the product of hardness cohesiveness (kg) as a measure of gumminess; the product of gumminess springiness (kg) as a measure of chewiness (Katsiari et al., 2002). Texture values were the mean of three replicates tested each sampling time. 2.5. Meltability Meltability of cheese samples was determined by two methods: Schreiber test and a method with a test tube. For Schreiber test, cheese samples were prepared using a glass borer and a sharp knife at 4–6 C. The specimens (4.1 cm 4 mm) were placed in a Petri dish and put into an electrical oven preheated to 230 C for 5 min. They were then removed and cooled for 30 min at room temperature. Specimen expansion was measured using a scale having six lines (A–E) marked on a concentric set of circles as described by Kosikowski (1982). Schreiber meltability was given as the mean of the six readings on the arbitrary scale of 0–10 units (Park, Rosenau, & Peleg, 1984). For the second method, 10 g of grated cheese were placed in a test tube (32 mm 250 mm) and were packed to form a plug at the bottom. The height of cheese was marked. The test tube was covered with an aluminium foil and holes were made to let the hot gas escape during heating. The test tube was kept vertically in a

Sensory evaluation was carried out with scoring test by nine panelists who are the members of Food Engineering Department. The panelists were selected on the basis of their interest in sensory evaluation of cheeses and trained by using commercial fresh kashar cheeses. The cheeses were evaluated for appearance, flavour, texture and overall acceptability using a score from 1 to 5. The equivalents of sensory characteristic scores were determined using commercial cheese samples obtained from local markets. The samples were presented to panelists as 15–20 g of cheese with water and bread for them to clean their palates between samples. Panelists were also requested to tick the defects on the panel scale in order to determine the reasons of decrease in scores. 2.7. Statistical analyses One-way analysis of variance for the data of chemical analyses (the factor being the fat replacer addition) and two-way analysis of variance for the data of textural, melting and sensory analyses (the factors being the fat replacer addition and the storage period) were carried out to determine the significance of the individual differences. Significant means were compared using Duncan test on the level of Po0:01 and standard deviations for mean values of chemical analyses were also calculated. Simple correlations were performed between the textural, melting and sensory properties of the cheese samples. All the statistical analyses were conducted using the SPSS (Version 8.0) commercial statistical package.

3. Results and discussion 3.1. Compositions of cheeses The compositions of full- and low-fat cheeses are given in Table 1. The moisture and protein contents of low-fat control cheese were significantly higher than those of full-fat cheese. Similar results were also observed by other authors (Katsiari & Voutsinas, 1994; Bryant, Ustunol, . & Steffe, 1995; Ustunol, Kawachi, & Steffe, 1995; Fenelon & Guinee, 1999; Rudan, Barbano, Yun, & Kindstedt, 1999; Fenelon & Guinee, 2000; Fenelon, O’Connor, & Guinee, 2000). The use of fat replacer affected the values of moisture, protein and moisture in non-fat substance of low-fat


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Table 1 Chemical composition of cheese samples (mean17standard deviation) Cheese samples FF2 Moisture (%) Fat (%) Protein (%) MNFS (%)3 Moisture/protein4

LF

47.78 71.02 24.50a70.40 24.71a70.59 63.28a71.02 1.93 a

SM

55.24 72.33 7.33b70.58 32.95c71.63 59.60b72.15 1.63 b

DL

59.20 70.55 6.67b71.15 29.22b70.69 63.43a70.41 2.02 c

RF

57.11 71.13 6.42b70.14 31.02bc71.79 61.03ab71.30 1.84 bc

57.88bc70.80 6.17b70.29 28.07ab71.32 61.68ab70.87 2.06

abc

Means within a row without a common superscript differ (Po0:01). Mean values of three replicates. 2 FF: full-fat cheese, LF: low-fat cheese, SM: low-fat cheese with SimplessesD-100, DL: low -fat cheese with Dairy-Lot, RF: low-fat cheese with RaftilinesHP. 3 Moisture in non-fat substance. 4 It was calculated using the means of moisture and protein. 1

cheese (Po0:01). One of the most important strategies for improving the properties of lower fat cheese is to increase its moisture content sufficiently to provide a ratio of moisture to protein or moisture in non-fat substance in the lower fat cheese that is equal or higher than its full fat counterpart (Broadbent, McMahon, Oberg, & Welker, 2001). Fortunately, the moisture contents and the values of the moisture in non-fat substance of low-fat cheeses with fat replacers were significantly higher than those of low-fat control cheese whereas the protein contents were significantly lower (Po0:01). Especially the value of the moisture in nonfat substance of the cheese with SimplessesD-100 was equal to that of full-fat cheese because of the increase of water binding capacity of the cheese matrix. Moreover, the ratios of moisture to protein for low-fat cheeses with fat replacers were higher than that of low-fat control cheese. The increased moisture content of low-fat cheeses produced by using fat replacers indicated that curd syneresis was retarted during cheese making. It has been suggested that water can bind directly to fat replacers and the fat replacers can interfere with the shrinkage of the casein matrix. Therefore, this lowers the driving force involved in expelling water from curd particles (McMahon et al., 1996). Similar results to present study have been obtained by Drake, et al. (1996a), McMahon et al. (1996), Rudan, Barbano and Kindstedt (1998), Sipahioglu et al. (1999), Zalazar et al. (2002) and Romeih et al. (2002) for low-fat Cheddar, low-fat Mozzarella, low-fat feta cheese, low-fat whitebrined cheese and low-fat soft cheeses. However, . Ku@ . uk . oner (1996) found that the low-fat Cheddar cheese had a similar protein content to the low-fat cheeses containing Simplesse and Dairy-Lo. 3.2. Textural properties The mean values of the TPA parameters are given in Table 2. The full-fat cheese was significantly softer than

the low-fat cheese without fat replacer (Po0:01). It is not suprising result because fat breaks up the protein matrix and plays the role of lubricant to provide smoothness and a softer texture (Romeih et al., 2002). The low fat cheese was the hardest cheese due to its high protein content. The low-fat cheeses containing SimplessesD-100 and RaftilinesHP had significantly lower hardness values than low-fat control cheese (Po0:01). On the other hand, the use of Dairy-Lot had no effect on the hardness values. This situation is very clear in Fig. 2a. The positive effect of SimplessesD-100 and RaftilinesHP on the hardness of low-fat kashar cheese could be attributed to both their high contents of moisture in non-fat substance and the ratio of moisture to protein and also to total filler volume of the low-fat cheeses produced by fat replacers. An increase in filler volume (moisture and fat) results in a decrease in the amount of protein matrix. Thus less force is required for a given deformation and the composite becomes softer (Rudan et al., 1998). The ratios of moisture to protein of LF, SM, DL and RF was calculated as 1.63, 2.02, 1.84 and 2.06, respectively. This order exactly fitted into the order of hardness values of low-fat cheeses. The decrease in hardness values determined during storage was not significant (P > 0:01). In the literature, it was reported that the use of different fat replacers decreased the TPA hardness of low-fat cheese (Drake, Herrett, Boylston, & Swanson, 1996b; Fenelon & Guinee, 1997; Rudan et al., 1998; Sipahioglu et al., 1999; Bhaskaracharya & Shah, 2001; Lobato-Calleros, Robles-Martinez, Caballero-Perez, Aguirre-Mandujano, & Vernon-Carter, 2001; Romeih et al., 2002). In contrast to these findings, Stevens and Shah (2002) found that the cheeses containing Maltrins were harder than skim milk Mozzarella cheese. It was observed that both the difference of means and the changes in the hardness values of all cheeses showed a similar trend to the changes in the gumminess and chewiness values during storage. A significant positive


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Table 2 Effect of treatment and storage time on the mean values of TPA parameters TPA parameters Hardness 1

Treatment (n ¼ 15)

FF LF SM DL RF

Significance of F Storage time (n ¼ 15)

1. 7. 30. 60. 90.

Significance of F

a

Springiness

Adhesiveness

a

b

Cohesiveness a

Gumminess a

0.71a 6.45c 2.19ab 4.98c 3.00b

9.49 38.52c 18.75b 31.02c 17.02ab

0.270 0.559c 0.400b 0.530c 0.488c

0.008 0a 0.018c 0a 0.005ab

0.260 0.280a 0.324ab 0.298ab 0.367b

0.000

0.000

0.000

0.003

0.000

0.000

0.451 0.474 0.451 0.441 0.462 0.352

0a 0a 0.002a 0.010b 0.019c 0.000

0.251a 0.275ab 0.318abc 0.338bc 0.355c 0.001

7.13 5.70 7.80 7.31 6.39 0.308

3.21 2.91 4.05 3.74 3.42 0.572

27.80 21.48 25.34 22.39 18.59 0.059

2.45 11.15c 5.44b 9.42c 5.88b

Chewiness

abc Means within a column without a common superscript differ (Po0:01). Lack of superscripts in a column indicates no significant differences among means (P > 0:01). 1 FF: full-fat cheese, LF: low-fat cheese, SM: low-fat cheese with SimplessesD-100, DL: low-fat cheese with Dairy-Lot, RF: low-fat cheese with RaftilinesHP. Po0:01:

0.7

60

0.6 0.5

40 30 20

cohesiveness

springiness

hardness (kg)

50 0.5

0.3

0.3 0.2 0.1

10

0.0

0.1

0 1 (a)

0.4

7 30 60 90 storage time (day)

1 (b)


1 (c)


Fig. 2. The hardness, springiness and cohesiveness values of cheese samples during storage ((E) FF: full-fat cheese; (’) LF: low-fat cheese; (m) SM: low-fat cheese with SimplessesD-100; (K) DL: low-fat cheese with Dairy-Lot; and () RF: low-fat cheese with RaftilinesHP).

correlation among these three TPA parameters was also found (Po0:01). Full-fat cheese had significantly lower springiness values than low-fat cheese during storage (Po0:01; Fig. 2b). SimplessesD-100 had a significant positive effect on springiness values of low-fat cheese (Po0:01) whereas Dairy-Lot and RaftilinesHP had no significant effect (P > 0:01). Romeih et al. (2002) found that the addition of SimplessesD-100 and Novagel decreased the values of springiness of low-fat white-brined cheese. However, Zalazar et al. (2002) observed that the use of 2% Dairy-Lot had no effect on the springiness values of low-fat Cremoso Argentino cheese. The adhesiveness started on the 30th day of storage for the cheese containing SimplessesD-100 and on the 60th day for the cheese containing RaftilinesHP and the values increased in the following days of storage. The low-fat control cheese and low-fat cheese with

Dairy-Lot had no adhesiveness during the 90-day storage. On the other hand, full-fat cheese was slightly adhesive on the 60th day of storage but this cheese was in the same group as low-fat control cheese statistically (P > 0:01). It was found that the mean of cohesiveness value of low-fat control cheese was higher than that of full-fat cheese. However, this was not significant (P > 0:01). The use of fat replacers increased cohesiveness values. Although all cheeses showed the similar trend until the 30th day of storage, the cohesiveness values of the lowfat cheeses, especially the one with RaftilinesHP, increased on the 60th and 90th days of storage (Fig. 2c). On the other hand, a decrease was observed in the values of full-fat cheese. As a result, as the fat content of fresh kashar cheese decreased, all the TPA parameters except adhesiveness increased. The similar results were observed by Bryant


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et al. (1995) who reported that as fat in cheese decreased, and the moisture increased, hardness, springiness and cohesiveness determined with Instron increased and adhesiveness decreased for Cheddar cheese and also by Rudan et al. (1999) who stated that the decrease of the fat content of Mozzarella cheese resulted in the increase of the TPA hardness, cohesiveness and springiness. The other important result of present study was that the use of the fat replacers except Dairy-Lot improved the textural properties of low-fat fresh kashar cheese. All fat replacers used in this study were fat mimetics which are polar and water soluble compounds. The polar nature of these fat mimetics is an advantage in that additional water is bound in cheese containing fat mimetics. Increase in moisture content of cheese results in improving the texture of low-fat cheese (Drake & Swanson, 1995). The possible reason why Dairy-Lot fails may be the use of standard heat treatment at 65 C for 30 min in cheese pasteurisation. Recommended usage of Dairy-Lot requires a heat treatment at 80 C for 10 min (in a portion of the milk) to bind the whey proteins in Dairy-Lot to the casein micelles in milk through bonding with k-kasein (McMahon et al., 1996). The other possible reason may be that Dairy-Lot has a much lower microparticulation size than SimplessesD-100 according to McMahon et al. (1996). Ma, Drake, Barbosa-Canovas, and Swanson (1997) found that the addition of protein, whey-based protein did not improve the protein matrix of the lowfat Cheddar cheese and a carbohydrate fat mimetic improved the rheological properties, but did not completely simulate the protein matrix of cheese. This result is not in agreement with the result observed for SimplessesD-100.

3.3. Melting properties Melting properties of fresh kashar cheese are very important because this cheese is used as an ingredient in sandwiches and pizzas in Turkey. The results of both tests are shown in Table 3. The full-fat cheese had significantly better meltability than that of low fat cheese (Po0:01). However, the use of fat replacers had no positive effect on the melting properties of low-fat cheese except RaftilinesHP which caused a slight increase in meltability. According to Rudan et al. (1998), materials based on carbohydrate and protein do not behave like materials based on fat under various conditions, especially when heated. There was no significant change in meltability determined by the method with test tube during the 90 days of storage (P > 0:01) but a significant increase in Schreiber meltability was observed on the 7th day of storage as clearly shown in Fig. 3 (Po0:01). In contrast to these results, Zalazar et al. (2002) found that low-fat cheeses without fat replacer and with Dairy-Lo had good melting behaviour, the reason for which was reported by these researchers the fact that the ability to melt is preserved if the fat reduction is accompanied by a higher moisture level. Low-fat cheese produced with MaltrinsM100 was reported to melt well by Stevens and Shah (2002). In contrast to present study, Fife et al. (1996) stated that the 28-day storage increased the meltability of low-fat Mozzarella cheese. 3.4. Sensory properties The means of the sensory scores of all sensory characteristics are given in Table 3. A significant

Table 3 Effect of treatment and storage time on the mean values of meltability and sensory properties Meltability Flow distance (mm) Treatment (n ¼ 15)

1

Storage time (n ¼ 15)

Significance of F abc

Schreiber test c

Appearance a

Texture c

Flavour c

Overall acceptability

FF LF SM DL RF

115.7 74.6b 55.1b 67.2b 89.0ab 0.000

7.13 1.71ab 2.05ab 1.57a 2.79b 0.000

4.08 3.65b 4.14a 3.90ab 3.66b 0.000

3.96 2.88a 3.46b 3.14ab 3.42b 0.000

3.92 2.97a 3.51b 2.97a 3.32ab 0.000

3.96a 2.93c 3.49b 2.96c 3.29b 0.000

1. 7. 30. 60. 90.

66.6 94.0 89.7 77.5 71.3 0.196

2.08a 3.33b 3.39b 3.48b 2.97ab 0.006

3.83 3.97 3.99 3.94 3.70 0.125

3.29 3.48 3.56 3.32 3.21 0.121

3.35ab 3.41ab 3.62b 3.26ab 3.07a 0.004

3.32ab 3.43a 3.55a 3.25ab 3.08b 0.005

Significance of F

a

Sensory properties

Means within a column without a common superscript differ (Po0:01). Lack of superscripts in a column indicates no significant differences among means (P > 0:01). 1 FF: full-fat cheese, LF: low-fat cheese, SM: low-fat cheese with SimplessesD-100, DL: low-fat cheese with Dairy-Lot, RF: low-at cheese with RaftilinesHP. Po0:01:


texture (score)

8

meltability

7 6 5 4 3

5

4.5 4 3.5 3 2.5 2 1.5 1

flavour (score)

9

371

4 3 2 1

1

7 30 60 storage time (day)

90

1

(b)


90

2

(a)

1

Fig. 4. The texture and flavour scores of cheese samples during storage ((E) FF: full-fat cheese; (’) LF: low-fat cheese; (m) SM: low-fat cheese with SimplessesD-100; (K) DL: low-fat cheese with DairyLot; and () RF: low-fat cheese with RaftilinesHP).

0 1


90

Fig. 3. The Schreiber meltability of cheese samples during storage ((E) FF: full-fat cheese, (’) LF: low-fat cheese, (m) SM: low-fat cheese with SimplessesD-100, (K) DL: low-fat cheese with DairyLot, () RF: low-fat cheese with RaftilinesHP).

difference (Po0:01) was observed between the scores of all sensory properties of full-fat and low-fat control cheeses. The low-fat control cheese had a more translucent surface and denser colour than full-fat cheese. The reason for translucency could be lack of the fat which provides opacity in cheese (Mistry & Anderson, 1993). Rudan et al. (1999) stated that the fat reduction made the Mozzarella cheese less white and more translucent. Merrill, Oberg, and McMahon (1994) also observed that fat reduction produced a greenish tint colour in the unmelted low-fat Mozzarella cheese. The colour of the low-fat fresh kashar cheeses containing fat replacers was different from that of low-fat control cheese. Moreover, the use of SimplessesD-100 corrected all appearance defects which were determined in low-fat fresh kashar cheese. The mean score of this cheese was also slightly higher than that of full-fat cheese. However, the addition of Dairy-Lot and RaftilinesHP had no significant effect (P > 0:01) on the appearance scores because of matter surface for DL and orange-red and nonhomogeneous colour for RF. Similarly, Drake et al. (1996a) stated that low-fat Cheddar cheese containing NovageltNC200, which is a carbohydrate-based fat replacer, was a deeper orange-red. Romeih et al. (2002) also reported that the low-fat white-brined cheese with SimplessesD-100 received a higher appearance score than the low-fat cheese without fat replacer and the one with Novagel and a similar score to full-fat cheese. The mean texture and flavour scores of full-fat cheese were significantly higher than those of low-fat cheeses (Po0:01). The effects of SimplessesD-100 and RaftilinesHP preventing undesirable hardness, rubbery texture and lack of flavour on the texture and flavour scores were significant. Although the low-fat cheeses with RaftilinesHP and SimplessesD-100 received closer scores to full-fat cheese until the 30th day of storage, a sharp decrease was observed for both criteria on the 60th and 90th days of storage due to the excessive

softening and salty flavour for SM and softening and off-flavour for RF (Fig. 4a and b). Zalazar et al. (2002) determined high moisture content for low-fat Cremoso Argentino cheese with Dairy-Lo and also reported that this moisture content was a problem for the shelf life of this product, as a consequence of excessive softening observed after 30th day of ripening. The texture scores of LF and DL were lower than those of others at the beginning of the storage. However, at the end of the storage, the texture scores of them were nearly the same as those of full-fat cheese. A big similarity was observed in the scores of texture, flavour and overall acceptability during storage. The results of sensory evaluation show that the texture and flavour of cheeses affected the overall acceptability more than the apperance of cheeses according to the correlation among these properties (Po0:01). The statistical ranking for overall acceptability scores was YL>SM=RF>DL=LF. Although the difference was not significant (P > 0:01), the low-fat cheese containing SimplessesD-100 was more acceptable than the low-fat cheese containing RaftilinesHP during storage except the score on the 60th day of storage. Dairy-Lot had no effect on the acceptability of low-fat cheese. The mean scores of overall acceptability during storage increased until the 30th day of storage and decreased on the further days of storage. The results of textural, melting and sensory properties were correlated to find the relations between these properties. A significant negative correlation was found between meltability and instrumental hardness (Po0:01). This result shows that the harder the cheese, the poorer the meltability. The texture and overall acceptability obtained by sensory evaluation were negatively correlated with the TPA hardness (Po0:01), springiness (Po0:01), gumminess (Po0:01) and chewiness (Po0:01). This means that the low-fat cheeses produced by using fat replacers, SimplessesD-100 and RaftilinesHP, which were softer, less elastic, less gummy and less chewy, had higher texture scores and were preferred by the panelists. But the decrease in the

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panel scores after 60th day of storage should not be forgotten. Although the correlation was not significant, there were negative correlations between textural and overall acceptability, and TPA adhesiveness. Moreover, a negative correlation was found between hardness and adhesiveness. These correlations mean that cheese became adhesive as the hardness decreased to some extent. Therefore, neither hard cheeses nor soft cheeses were preferred.

4. Conclusions The low-fat cheese without fat replacer was significantly harder, more elastic, gummier and more chewy and had also poorer meltability, lower appearance, texture, flavour and overall acceptability scores than the full-fat cheese. All appearance defects were corrected by using SimplessesD-100. The use of SimplessesD-100 and RaftilinesHP improved the textural and sensory properties of low-fat fresh kashar cheese until the 30th day of storage whereas defects were observed on the 60th and 90th days of storage. These results indicated that SimplessesD-100 and RaftilinesHP can improve texture and sensory properties of low-fat fresh kashar cheese. However, the shelf life of the cheese with these fat replacers has to be shorter than 60 days and also further investigations are needed to prevent the defects which were shown after the 60th day of storage.

Acknowledgements The present study has been supported by Pinar Dairy Company, Dora Company and The Research and Application Center of Ege University.

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