Chemical, Rheological, Microbial and Microstructural ...

American Journal of Food Science and Nutrition Research 2016; 3(4): 46-55

http://www.openscienceonline.com/journal/fsnr

ISSN: 2381-621X (Print); ISSN: 2381-6228 (Online)

Chemical, Rheological, Microbial and Microstructural Characteristics of Jameed Made from Sheep, Goat and Cow Buttermilk or Skim Milk

Mohamed N. Hamad1, Magdy M. Ismail

2, *, Reham K. A. El-Menawy

2

1Department of Dairying, Faculty of Agriculture, Damietta University, Damietta, Egypt 2Dairy Technology Department, Animal Production Research Institute, Agricultural Research Center, Dokki, Giza, Egypt

Email address

[email protected] (M. M. Ismail) *Corresponding author

To cite this article Mohamed N. Hamad, Magdy M. Ismail, Reham K. A. El-Menawy. Chemical, Rheological, Microbial and Microstructural Characteristics of

Jameed Made from Sheep, Goat and Cow Buttermilk or Skim Milk. American Journal of Food Science and Nutrition Research.

Vol. 3, No. 4, 2016, pp. 46-55.

Received: May 19, 2016; Accepted: May 29, 2016; Published: June 22, 2016

Abstract

Jameed is basically a hard cheese-like product considered a very stable and safe dried fermented milk product. It is usually

made from sheep buttermilk. The aim of this study was using goat and cow buttermilk or skim milk in preparing of jameed

instead of sheep buttermilk. Five treatments of jameed were made from sheep, goat and cow buttermilk and also from goat and

cow skim milk. The obtained results showed that yield, total solids, ash, salt in moisture, total protein and non-protein-nitrogen

values of jameed made from sheep buttermilk were higher than that of jameed prepared from goat or cow butter and goat or

cow skim milk. Sheep buttermilk jameed contained low acidity values than those in jameed prepared from goat and cow

buttermilk. Utilization of goat and cow skim milk in jameed making decreased titratable acidity and water soluble nitrogen and

increased pH values. Jameed made from goat skim milk had the highest fat contents. Utilization of goat and cow buttermilk in

jameed manufacture increased total viable bacterial count, lactic acid bacteria and proteolytic bacteria. Sheep buttermilk

jameed showed the best wetability followed by goat and cow skim milk jameed. Levels of jameed syneresis were higher in

goat and cow buttermilk jameed than that of jameed made from sheep buttermilk. All values of the textural properties were

higher in sheep buttermilk jameed than those of the other treatments. From scanning electron microscopy, it is observed that

the protein structure was completely different among stored jameed samples. Jameed with good properties can be made from

goat and cow buttermilk or skim milk.

Keywords

Jameed, Cow Buttermilk, Rheological and Microstructural Characteristics, Skim Milk

1. Introduction

Fermented dairy foods have constituted a vital part of

human diet in many regions of the world since times

immemorial. They have been consumed ever since the

domestication of animals. Evidence for the use of fermented

milks comes from archeological findings associated with the

Sumerians and Babylonians of Mesopotamia, the Pharoses of

northeast Africa and the Indo-Aryans of the Indian

subcontinent. It was reported that consuming fermented dairy

products caused to longevity [1, 2].

Jameed is a fermented dried dairy product in the form of

stone hard balls or other shapes. It has a long history with the

Bedouin life style and had long been known for its easy

preparation and storage for future use. Jameed is widely used

as a common traditional food in several Mediterranean

countries including Jordan, Syria, Saudi Arabia, Iraq and

Egypt. Several names are being given to jameed, i.e. oggott

in Arab Gulf States and jameed in Jordan and Syria. Jameed

is used mainly in the preparation of the popular traditional

dish called ‘‘mansaf’’. ‘‘Mansaf’’ is made from rice and meat

47 Mohamed N. Hamad et al.: Chemical, Rheological, Microbial and Microstructural Characteristics of Jameed Made from Sheep,

Goat and Cow Buttermilk or Skim Milk

and sauce. The sauce is made by adding cooked meat to

dissolving jameed (reconstituted with warm water) then

boiling the mixture for about 15 min to produce the sauce

named ‘‘sharap’’ [3]. In this sense, Al Groum [4] showed that

jameed is one of the main fermented milk product produced

in Jordan. It is usually prepared at household scale by the

traditional method which depends on fermentation of milk

then churning for separating butter. The resulted buttermilk is

used for jameed production.

Several techniques were used by Quasem et al. [5] to

improve the solubility of solar-dried jameed by addition of

additives and application of heat treatment for buttermilk. It

was reported that the best results could be achieved by

heating the buttermilk for 3 min at 55ºC, and addition of

carrageenan (0.15%) as additive. Jameed powder produced

by spray-drying technique was studied by Shaker et al. [6]

using concentrated partially defatted yogurt ‘‘makheed’’.

Jameed is usually made from sheep buttermilk using

traditional methods which may be take long time in

processing and at the same time the amount of sheep milk is

no longer sufficient to meet the growing demand of jameed.

Therefore the current study aim was to make a big boost in

jameed production through using goat and cow buttermilk or

skim milk instead of sheep buttermilk.

2. Materials and Methods

2.1. Materials

Fresh sheep’s, goat’s and cow's milks were obtained from

El-Serw Animal Production Research Station, Animal

Production Research Institute, Agricultural Research Center,

Egypt. A commercial classic yoghurt starter containing

Streptococcus thermophillus and Lactobacillus delbrueckii

subsp. bulgaricus (1:1) (Chr. Hansen’s Lab A/S Copenhagen,

Denmark) was used. Starter cultures were in freeze-dried

direct-to-vat set form and stored at –18°C until used.

2.2. Methods

2.2.1. Jameed Manufacture

Jameed treatments were made according to the traditional

method described by Quasem et al. [5]. Five treatments of

jameed were made from sheep, goat and cow butter or skim

milk as follow:

� Treatment A: Jameed made from sheep buttermilk

(control),

� Treatment B: Jameed made from goat buttermilk,

� Treatment C: Jameed made from goat skim milk,

� Treatment D: Jameed made from cow buttermilk and

� Treatment E: Jameed made from cow skim milk.

Figure 1 illustrates the jameed manufacturing procedure in

the arena of bromatology. The shaped jameed balls were

placed on trays lined with cheesecloth and dried in the shade

for 24h thin direct sun to constant weigh (~15 days). The

dried jameed balls were packaged in cloth bags which were

put in plastic containers and stored at room temperature for 6

months. Samples were analyzed when fresh (jameed curd)

and after 15, 30, 60, 90, 120, 150 and 180 days of storage

period.

2.2.2. Methods of Analysis

(1) Chemical Analysis

Total solids, fat, total nitrogen and ash contents of samples

were determined according to the AOAC method [7].

Titratable acidity in terms of % lactic acid was measured by

titrating 10g of sample mixed with 10ml of boiling distilled

water against 0.1 N NaOH using a 0.5% phenolphthalein

indicator to an end point of faint pink color [8]. The pH of the

sample was measured at 17 to 20°C using a pH meter

(Corning pH/ion analyzer 350, Corning, NY) after calibration

with standard buffers (pH 4.0 and 7.0). Water soluble

nitrogen (WSN) and non-protein-nitrogen (NPN) of jameed

were estimated according to Ling [9]. The Volhard’s method

as described by Richardson [10] was used to determine the

salt content of jameed. Salt in moisture percentage of the

cheese was estimated as follow:

(Salt percentage x 100) / (moisture percentage + Salt

percentage)

(2) Microbiological Analyses

Jameed samples were analyzed for total viable bacterial

count (TVBC), lactic acid bacteria (LAB), coliform,

proteolytic bacteria, moulds and yeast counts according to

the methods described by the American Public Health

Association [11].

(3) Textural Measurements

Force and torque measurements of jameed treatments

stored for six months were measured using a Texturometer

model Mecmesin Emperor TMLite 1.17(USA). Mechanical

primary characteristics of hardness, springiness, gumminess

and cohesiveness and also the secondary characteristic of

chewiness (hardness x cohesiveness x springiness) were

determined from the deformation Emperor TMLite Graph.

Because jameed samples were very hard, they were soaked in

distilled water for 6h at room temperature before

measurements.

(4) Wetability Test

A cube weighing ca. 45 g of jameed was cut using a hand

saw from a whole jameed ball; 315 ml water were added to

the piece placed in 500 ml cup and soaked for 24 h [5]. The

excess free water was carefully decanting weighed to

calculate the soaked amount as follows:

Absorbed water (%) = [(315 ml water-X) /Weight of cubs

in g] x 100

X= the weight of excess water in g.

(5) Syneresis (Whey Separation) Test

The soaked cube (45 g) was mixed with (315 ml water) for

2 minutes using electrical hand mixer (Hinari, model FM2,

China) with the whipping accessory. The dispersed jameed

was transferred to a 100 ml graduated cylinder and the clear

zone was measured after 1 h and 24 h [5]. Syneresis (whey

separation) was calculated, as follow:

American Journal of Food Science and Nutrition Research 2016; 3(4): 46-55 48

Syneresis (%) = (X/Y) ×100

Where;

X= the height of the clear zone and

Y= total height of jameed dispersion.

(6) Scanning Electron Microscopy (SEM)

Examination

Jameed samples were prepared for SEM according to the

method of Brooker and Wells [12]. The specimens were

viewed in a scanning electron microscope (JXA-840A

Electron Probe Microanalyzer-JEOL-Japan) after dehydrated

using Critical Point Dried instrument and coating with gold

using S150A Sputter Coater-Edwards England.

(7) Statistical Analysis

The obtained results were statistically analyzed using a

software package [13] based on analysis of variance. When

F-test was significant, least significant difference (LSD) was

calculated according to Duncan [14] for the comparison

between means. The data presented, in the tables, are the

mean (± standard deviation) of 3 experiments.

Fig. 1. The processing steps for jameed made from sheep, goat and cow butter or skim milk.



3. Results and Discussion

3.1. Chemical Composition of Milk Used in

Jameed Manufacture

Sheep buttermilk is richer in total solids, fat, protein and

solids-not-fat (SNF) than goat or cow buttermilk (Table 1).

Park et al. [15] showed that the differences in the content of

solids between sheep and goat milk also affect their physical

properties. Density and titratable acidity and viscosity of

sheep milk are higher than of goat milk, while the freezing

point of sheep milk is lower than in goat milk.

As it is expected, acidity concentrations of buttermilk were

the greatest between various samples. Among buttermilk

treatments, sheep buttermilk recorded the highest acidity

level.

Regarding skim milk, TS contents of goat and cow skim

milk were cloth to each other. However, the fat and total

protein values were higher in the former than those of the

latter. On the other side, TS levels of goat or cow skim milk

were higher than those measured in buttermilk resulted from

the same milks. This may be due to lowering of lactose

contents in buttermilk as a result of fermentation and

producing lactic acid. Because fat globules of goat’s milk

don’t easily separate by separator as occurred in cow’s milk,

fat concentration of goat skim milk was the highest as

compared with those found in buttermilk or cow skim milk.

Total protein contents were slightly lower in goat and cow

skim milk than that of buttermilk.

Table 1. Chemical composition of milk used in jameed manufacture.

Treatments Acidity % pH values TS % Fat % Total Protein % SNF %

Sheep buttermilk 0.99a 5.92b 7.81de 0.7c 5.10a 6.50ab

Goat buttermilk 0.93a 6.15b 6.61e 0.6c 3.20a 6.11b

Goat skim milk 0.17b 6.60a 9.97dbc 0.9c 3.05a 9.07ab

Cow buttermilk 0.90a 6.19b 6.71de 0.5c 3.25a 6.21ab

Cow skim milk 0.18b 6.58a 9.47dec 0.4c 2.98a 8.97ab

abcde Letters indicate significant differences between milk treatments

3.2. Chemical Composition of Jameed During

Storage Period

However sheep buttermilk had higher acidity ratios than those

of goat and cow buttermilk, but jameed made from of sheep

buttermilk contained low acidity values as compared with those

measured in jameed prepared from goat and cow buttermilk

(Table 2). In fresh jameed (paste) and during storage period, cow

buttermilk jameed possessed the highest acidity values.

Utilization of goat and cow skim milk in jameed making

(treatments C and E respectively) decreased titratable acidity and

increased pH values. Cow skim milk jameed recorded the lowest

acidity values among various treatments. Furthermore, the rates

of acidity development within storage were lower in skim milk

jameed than that of buttermilk one.

As a result of high TS and fat contents of sheep buttermilk,

jameed manufactured from it had higher values of these

components than those of goat or cow buttermilk jameed.

Results in Table 1 indicate that goat and cow skim milk

contained the greatest TS content. In spite of that outcomes

of Table 2 clear that goat and cow skim milk jameed had the

lowest TS levels. This discrepancy in results might be

interpreted on the bases that skim milk contained high lactose

concentration comparing with buttermilk. During jameed

manufacturing, the majority of lactose content was fermented

to lactic acid which loosed in the whey within draining. On

the other hand, jameed made from goat skim milk contained

the highest fat values. This may be attributed to the high fat

content of goat skim milk (0.9%). As it well known, fat

globules in goat’s milk are difficult to be separated by

separator. Regarding to the ash concentrations, sheep

buttermilk jameed had the highest whereas cow skim milk

jameed contained the lowest. In the same trend, salt in

moisture values were high in sheep buttermilk jameed and

low in skim milk one.

On the whole, the chemical composition values of jameed

obtained in this study were within ranges described by

Alu’Datt et al. [16] while were lower than stated by Bawadi

and Al-Sahawneh [17]. Alu’Datt et al. [16] showed that fat

and ash values of salted sun-dried jameed were 10.1 and

15.5% respectively. Conversely, Bawadi and Al-Sahawneh

[17] stated that carbohydrate, protein and fat levels of jameed

were 3.4, 57.02 and 22.25% respectively.

Al-Omari et al. [18] and Mazahreh et al. [19] reported that

jameed has a high nutritive value, with a protein content of

about (48–54%), fat (18–22%) and ash (12–13%) and

characterized with its long shelf life.

Regardless of milk type used in jameed production,

acidity, pH, TS, fat, ash, salt and salt in moisture values of

various samples increased during storage period. The most

vivid increasing was occurred through the drying period (15

days). Increasing of acidity and decreasing of pH values of

course due to the activity of the starter culture while moisture

evaporation was the main cause for increasing of TS, fat, ash,

salt and salt in moisture concentrations of jameed.

3.3. Changes in Nitrogen Fractions of

Jameed during Storage Period

The effect of milk type or storage period on nitrogen

fractions of jameed was significant (P<0.001).

Concentrations of total protein were higher in sheep

buttermilk jameed than those of jameed made from goat and

cow buttermilk (Table 3). Using goat buttermilk slightly


decreased total protein values in jameed as compared with

cow buttermilk one. Surprisingly, sharp decline in total

protein content was noticed in jameed paste prepared from

goat or cow skim milk. After 15 days and toward the end of

storage period, total protein values of skim milk jameed were

also lower than that of buttermilk jameed but with lesser

extent from fresh paste. These findings refer to higher

moisture content in paste of skim milk jameed so, higher

evaporation rates within draying process. Levels of total

protein of treatments C and E after 30 days of storage were

46.37 and 48.96% respectively.

In contrast to the results of total protein, concentrations of

water soluble nitrogen (WSN) raised in goat and cow

buttermilk jameed comparing with that of sheep buttermilk

jameed. At the beginning and during storage, goat buttermilk

jameed contained the highest WSN values followed by cow

buttermilk one. Not only were those, but also goat and cow

buttermilk jameed possessed the greatest rates of WSN

development during storage period. On the other side, using

goat or cow skim milk in jameed manufacture reduced WSN

values. Cow skim milk jameed recoded the lowest WSN

content between different samples.

The trend of NPN data was similar to that of total protein.

Sheep buttermilk had higher NPN levels than that of jameed

made from goat and cow milk. Also, as was noted in total

protein, skim milk jameed especially prepared from goat

skim milk contained the lowest concentrations of NPN.

Generally, in various jameed treatments, total protein, WSN

and NPN contents significantly increased during storage

period. Increasing of WSN and NPN contents may be due to

the degradation in jameed protein during storage due to

starter bacteria activity.

Table 2. Effect of using goat and cow buttermilk or skim milk on some physicochemical properties of jameed.

Properties Treatments Storage period (days)

Means Fresh 15 30 60 90 120 150 180

Acidity

%

A 2.05 3.48 4.11 4.46 4.78 5.01 5.25 5.36 4.31a

B 2.15 3.60 4.32 4.67 4.90 5.17 5.39 5.55 4.47a

C 1.80 2.58 2.95 3.22 3.48 3.67 3.90 4.05 3.20b

D 2.18 3.64 4.39 4.75 4.98 5.22 5.45 5.64 4.53a

E 1.75 2.50 2.87 3.13 3.39 3.63 3.84 3.96 3.13b

Means 1.98C 3.16CB 3.73AB 4.05AB 4.31AB 4.54A 4.77A 4.91A

pH

values

A 4.98 4.43 4.19 3.91 3.70 3.55 3.41 3.36 3.94a

B 4.91 4.28 4.01 3.79 3.55 3.44 3.36 3.24 3.82a

C 5.30 4.77 4.65 4.52 4.43 4.27 4.15 4.05 4.52a

D 4.90 4.25 3.95 3.71 3.50 3.40 3.32 3.20 3.78a

E 5.39 4.80 4.70 4.61 4.50 4.32 4.24 4.13 4.59a

Means 5.10A 4.51AB 4.30AB 4.11AB 3.94AB 3.80B 3.70B 3.60B

TS

%

A 48.67 82.00 84.95 86.12 87.08 87.87 88.58 89.06 81.79a

B 42.23 79.33 81.94 83.73 84.70 85.59 86.23 86.85 78.82b

C 32.21 75.30 77.82 78.93 80.06 80.85 81.48 82.07 73.59c

D 44.20 80.25 83.11 84.35 85.24 86.25 86.80 87.43 79.70b

E 33.92 76.05 78.67 79.75 80.77 81.64 82.25 82.94 74.49c

Means 40.25F 78.59E 81.30D 82.58CD 83.57CB 84.44AB 85.07A 85.67A

Fat

%

A 3.85 10.50 10.94 11.27 11.35 11.44 11.53 11.75 10.33ab

B 3.80 10.56 10.91 11.10 11.24 11.35 11.48 11.64 10.26ab

C 4.24 11.23 11.52 11.65 11.80 11.94 12.12 12.26 10.84a

D 3.51 9.97 10.23 10.24 10.31 10.46 10.53 10.67 9.49b

E 3.12 9.86 9.98 10.13 10.25 10.35 10.41 10.54 9.33b

Means 3.70B 10.42A 10.72A 10.88A 10.99A 11.11A 11.21A 11.37A

Ash

%

A 11.50 14.87 14.95 15.38 15.59 15.81 16.04 16.14 15.03a

B 10.21 13.62 13.75 13.97 14.19 14.43 14.59 14.64 13.67b

C 10.05 13.49 13.73 13.91 14.17 14.34 14.47 14.60 13.59b

D 10.13 13.75 13.95 14.23 14.49 14.78 14.83 14.97 13.89b

E 9.88 13.25 13.47 13.65 13.88 14.19 14.35 14.59 13.41b

Means 10.35B 13.80A 13.97A 14.23A 14.46A 14.71A 14.86A 14.99A

Salt

%

A 7.02 10.23 10.58 10.62 10.78 10.87 10.95 11.07 10.26a

B 6.18 9.40 9.81 9.92 10.07 10.18 10.25 10.38 9.52ab

C 6.34 9.61 10.04 10.15 10.25 10.38 10.47 10.55 9.72ab

D 6.08 9.05 9.23 9.48 9.83 9.97 10.10 10.25 9.52b

E 5.83 9.57 9.73 9.98 10.08 10.23 10.37 10.51 9.54ab

Means 6.29B 9.57A 9.88A 10.03A 10.20A 10.33A 10.43A 10.55A

Salt in

moisture

%

A 12.03 36.23 41.27 43.34 45.48 47.26 48.94 50.29 40.60a

B 9.66 31.26 35.19 37.87 39.69 41.39 42.67 44.11 35.23b

C 8.55 28.00 31.16 32.51 33.95 35.15 36.11 37.04 30.31c

D 9.83 31.42 29.71 37.72 39.97 42.03 43.34 44.91 34.87b

E 8.10 28.55 31.32 33.01 35.44 35.78 36.87 38.12 30.90c

Means 9.63G 31.09F 33.73E 36.89D 38.91C 40.32B 41.59B 42.89A

abcde Letters indicate significant differences between jameed treatments ABCD Letters indicate significant differences between storage times



3.4. Changes in Microbial Counts of Jameed

During Storage

Results of Table 4 show the enumeration of total viable

bacterial count (TVBC), lactic acid bacteria (LAB),

proteolytic bacteria, moulds and yeast during storage of

jameed. Coliform bacteria were not detected over the storage

period in various samples. These outcomes confirm the

hygienic conditions of the manufacture. Counterproductive

were reported by Al Omari et al. [18] who showed that the

coliform counts in sheep or cow buttermilk jameed were <

10. They considered these low numbers of coliform indicate

that Jameed is a safe food, from the microbiological point of

view even if it’s produced under relatively uncontrolled

condition as done by the Bedouins and farmers. Several

preserving factors contribute to this safety. The low water

activity due to its low moisture content and high salt

concentration, a pH below 4.0 and the combined effect of salt

and lactic acid that inhibit the growth of pathogens and most

spoilage microorganisms, make the Jameed a safe product for

consumer health.

Utilization of goat and cow buttermilk in jameed

manufacture significantly (P<0.05) increased TVBC in fresh

product and during storage period. Jameed made from skim

milk had the lowest numbers of these microorganisms. On

the contrary, rates of survival loss of TVBC through storage

period were higher for jameed made from goat and cow skim

milk than that of buttermilk jameed. Values of loss of

survival for samples A, B, C, D and E were 85.07, 81.39,

85.45, 83.54 and 87.50% respectively. Numbers of TVBC

obtained in our study were higher than those found by Al

Omari et al. [18] who mentioned that the standard plate

counts were 7 x 102 and 5 x 10

2 CFU/g for solar dried

Jameed from sheep and cow buttermilk respectively. As

cleared from Table 4, counts of TVBC of jameed at the end

of storage period were 10 x 103 and 13 x 10

3 for sheep and

cow buttermilk jameed respectively.

Table 3. Effect of using goat and cow buttermilk or skim milk on nitrogen fractions of jameed.


Means Fresh 15 30 60 90 120 150 180

Total protein

%

A 29.55 51.13 53.05 53.16 53.31 53.61 53.70 53.81 50.16a

B 24.61 48.80 50.05 50.98 51.22 51.54 51.62 51.77 47.57c

C 15.01 44.86 46.37 46.80 47.21 47.45 47.59 47.68 42.87e

D 26.99 49.98 51.55 51.87 52.13 52.39 52.54 52.64 48.76b

E 17.53 46.98 48.96 49.28 49.59 49.77 49.89 50.04 45.25d

Means 22.74C 48.35B 49.99A 50.42A 50.69A 50.95A 51.07A 51.19A

WSN

%

A 0.468 1.401 1.435 1.463 1.478 1.492 1.510 1.521 1.346c

B 0.481 1.433 1.473 1.505 1.523 1.541 1.565 1.587 1.388a

C

D

0.454

0.474

1.180

1.419

1.198

1.456

1.218

1.486

1.230

1.502

1.241

1.520

1.256

1.539

1.267

1.550

1.135d

1.368b

E 0.443 1.157 1.174 1.190 1.201 1.212 1.225 1.239 1.104e

Means 0.472G 1.318F 1.347E 1.372D 1.387C 1.401B 1.419A 1.431A

WSN/TN

%

A 10.10 17.49 17.26 17.26 17.70 17.76 17.95 18.04 16.73b

B

C

12.49

19.32

18.75

16.78

18.78

16.50

18.83

16.61

18.99

16.64

19.09

16.70

19.34

16.85

19.65

16.96

18.23a

17.04b

D 11.20 18.12 18.04 18.27 18.38 18.51 18.69 18.78 17.50ab

E 16.16 15.72 15.30 15.41 15.45 15.53 15.68 15.68 15.62c

Means 13.85B 17.37A 17.18A 17.34A 17.43A 17.52A 17.70A 17.80A

NPN

%

A 0.089 0.271 0.280 0.290 0.298 0.310 0.317 0.325 0.272a

B 0.084 0.263 0.269 0.276 0.282 0.290 0.296 0.302 0.258b

C 0.077 0.242 0.247 0.253 0.258 0.265 0.270 0.276 0.236d

D 0.081 0.259 0.266 0.274 0.281 0.288 0.293 0.301 0.25bc

E 0.079 0.249 0.256 0.264 0.270 0.277 0.283 0.289 0.24dc

Means 0.082F 0.257E 0.264ED 0.217CD 0.278CB 0.286AB 0.292A 0.299A

NPN/TN

%

A 1.92 3.38 3.36 3.48 3.56 3.69 3.76 3.85 3.37a

B 2.18 3.44 3.43 3.51 3.51 3.59 3.65 3.72 3.38a

C 3.27 3.44 3.40 3.45 3.49 3.56 3.62 3.69 3.49a

D 1.87 3.30 3.29 3.37 3.43 3.50 3.56 3.64 3.24a

E 2.88 3.51 3.33 3.41 3.47 3.55 3.62 3.68 3.43a

Means 2.42B 3.36AB 3.41AB 3.44AB 3.49AB 3.58AB 3.64AB 3.72A


It could be seen from data of Table 4 that higher counts of

lactic acid bacteria were detected in goat and cow buttermilk

jameed than those found in sheep buttermilk one. Goat and

cow skim milk jameed contained the lowest numbers of


lactic acid bacteria. Generally, goat buttermilk jameed had

the highest counts while cow skim milk jameed had the

lowest numbers of lactic acid bacteria. Values of the loss of

survival for lactic bacteria during jameed storage possessed

the opposite trend where increased in skim milk jameed than

that of buttermilk one. Comparing the numbers of TVBC and

lactic acid bacteria revealed that the dominant

microorganisms in jameed are lactic acid bacteria.

The results of microbial tests showed that few numbers of

proteolytic bacteria were detected in various jameed samples.

As it noted in TVBC and lactic acid bacteria, counts of

proteolytic bacteria were higher in goat and cow buttermilk

jameed than those of control (treatment A). Also, goat and

cow skim milk jameed had the lowest counts proteolytic

bacteria. It is worth to note that the outcomes of proteolytic

bacteria in Table 4 are compatible with the results of WSN in

Table 3. Higher counts of proteolytic bacteria in goat and

cow buttermilk jameed caused more protein degradation

consequently more WSN production in these treatments.

Till 60 days of storage, moulds and yeasts were not

detected in different jameed samples. They appeared on the

ninety day and increased during storage period. Using goat

and cow buttermilk in jameed preparation increased the

counts of moulds and yeasts whereas using goat and cow

skim milk reduced them.

Whilst storage time progressive, counts of TVBC, lactic

acid bacteria and proteolytic bacteria lowered in various

jameed treatments. This decrease could be evidently

attributed to the decreasing of moisture and increasing in salt

and acidity levels which controlled the rate of bacterial

growth or acted as bactericidal agent.

3.5. Changes in Solubility of Jameed During

Storage

Data of the effect of using sheep, goat and cow buttermilk

and goat or cow skim milk on solubility of jameed are shown

in Table 5. At the end of drying stage (after 15 days) and

within storage, sheep buttermilk jameed showed the best

results of solubility as measured by wetability. Goat skim

milk jameed followed by cow skim milk one gave the second

wetability grades whereas cow buttermilk jameed had the

lowest wetability values. Generally, the results of wetability

are in the ranges reported by Quasem et al. [5].

In adversely trend to wetability, levels of jameed syneresis

determined after 1 or 24 h of mixing with water were higher

in goat and cow buttermilk jameed than that of jameed made

from sheep buttermilk. At the end of storage period, values of

syneresis of jameed made from sheep buttermilk or goat and

cow skim milk were close to each other. As it is expected,

values of syneresis determined after 24h were higher than

those measured after 1h. General speaking, values of

wetability and syneresis increased gradually during storage

period to reach the maximum after 180 days.

Table 4. Effect of using goat and cow buttermilk or skim milk on some microbial groups of jameed.


Means Fresh 15 30 60 90 120 150 180

TVBC

(x 103)

A 67 35 29 22 18 15 13 10 26.75c

B 86 44 37 28 25 21 19 16 34.50a

C 55 21 18 16 15 13 10 8 19.50d

D 79 40 33 25 20 17 16 13 30.37b

E 48 17 15 13 11 10 7 6 15.87e

Means 67.0A 32.4B 26.4C 20.8D 17.8E 15.2F 13.0G 10.6H

Lactic acid bacteria

(x 103)

A 55 28 21 16 13 10 9 8 20.00c

B

C

74

41

39

18

34

16

24

12

20

10

15

9

12

7

10

3

28.50a

14.50d

D 65 32 28 20 16 12 10 9 24.00b

E 33 13 10 9 7 5 4 0.8 10.22e

Means 53.6A 26.0B 21.8C 16.2D 13.2E 10.2F 8.4G 6.2H

Proteolytic

bacteria (x 103)

A 6 0.9 0.7 0.30 0.10 0.08 0.05 0.02 1.69bc

B 10 2.0 1.0 0.80 0.60 0.30 0.20 0.09 1.87a

C 4 0.5 0.3 0.08 0.07 0.04 0.02 0.01 0.63dc

D 8 1.0 0.8 0.50 0.20 0.14 0.08 0.05 1.35b

E 3 0.2 0.08 0.07 0.06 0.04 0.02 0.01 0.43d

Means 6.20A 0.92B 0.58BC 0.35BC 0.29C 0.12C 0.07C 0.04C

Mould

&

Yeast (x103)

A ND* ND ND ND 0.3 0.4 0.7 0.9 0.22ab

B ND ND ND ND 0.5 0.7 1.0 1.13 0.42a

C ND ND ND ND 0.1 0.2 0.4 0.7 0.17ab

D ND ND ND ND 0.4 0.5 0.8 1.0 0.34a

E ND ND ND ND 0.09 0.1 0.2 0.4 0.04b

Means ND ND ND ND 0.28CD 0.38CB 0.62AB 0.73A


* ND: not detected



Table 5. Effect of using goat and cow buttermilk or skim milk on wetability and syneresis of jameed.


Means 15 30 60 90 120 150 180

Wetability

(%)

A 210.85 220.73 225.22 227.12 228.79 230.91 233.34 225.28a

B 189.56 198.22 203.05 207.17 209.00 211.05 213.34 204.48b

C 198.33 204.70 211.06 214.37 217.00 219.35 220.15 212.14b

D 169.60 175.33 177.02 178.59 180.00 182.64 184.21 176.77c

E 190.75 201.14 208.27 211.06 215.70 216.36 218.11 208.77b

Means 191.81C 200.00CB 204.92AB 207.66AB 210.10AB 210.06AB 213.83A

Syneresis %

(after 1h of

mixing with

water)

A 39.84 47.87 48.03 51.97 54.67 55.84 57.92 50.88b

B 45.56 52.90 54.03 57.12 59.67 60.35 62.56 56.03b

C 41.88 48.22 49.09 52.81 55.78 57.16 58.28 51.89d

D 50.89 56.08 58.14 60.04 62.00 63.10 64.34 59.23a

E 44.60 50.73 51.22 54.72 56.81 57.90 58.83 53.54c

Means 44.55E 51.16D 52.10D 55.33C 57.79B 58.87B 60.39A

Syneresis %

(after 24h of

mixing with

water)

A 42.42 50.00 50.11 54.65 57.14 60.12 63.16 53.94d

B 47.88 55.03 57.56 59.85 62.16 63.85 65.07 58.84b

C 43.78 50.84 51.76 54.18 57.00 59.87 63.10 54.36d

D 52.98 58.08 61.94 63.33 65.05 66.76 67.87 62.29a

E 47.00 53.08 53.70 56.84 58.76 60.81 63.87 56.51c

Means 46.81G 53.51F 55.11E 57.77D 60.02C 62.38B 64.71A


3.6. Changes in Textural Characterizes of

Jameed at the end of Storage Period

All values of the textural properties were higher in sheep

buttermilk jameed (sample A) than those of the remaining

treatments (Table 6). A comparison between results of

textural properties of jameed made from goat and cow

buttermilk or goat and cow skim milk show that cow

buttermilk jameed (sample D) followed by goat buttermilk

jameed (sample B) had the highest hardness, cohesiveness,

gumminess and chewiness values, but the lowest springiness

values. Quite opposite trend was noticed in jameed prepared

from goat and cow skim milk where the levels of springiness

were the highest and values of other textural properties were

the lowest. On the other hand, the hardness, cohesiveness,

gumminess and chewiness values were higher while

springiness values were lower in cow skim milk jameed than

that of goat skim milk one. Lobato-Calleros et al. [20]

showed that the instrumental textural characteristics of

hardness and adhesiveness were negatively correlated to

cohesiveness and springiness.

Increasing of hardness in buttermilk jameed may associate

with high acidity and low pH in these samples (Table 2). In

supplementary, Thomas [21] stated that with low pH of the

processed cheese, the protein aggregates and firmness

increased. Also, Awad et al. [22] found that the hardness

increased with decreasing the pH in block processed cheese.

Table 6. Textural properties of jameed at the end of storage period.

Treatments Hardness

(N)

Cohesiveness

(B/A area) Springiness (mm) Gumminess (N) Chewiness (N/mm)

A 22.10a 0.309a 1.497a

6.846a 9.573a

B 19.80a 0.183a 0.615b 5.504b 8.949a

C 14.95b 0.156a 0.754b 3.251d 6.421b

D 20.10a 0.238a 0.593b 6.678a 9.202a

E 15.87b 0.170a 0.624b 4.365c 6.854b

abcde Letters indicate significant differences between jameed treatments

3.7. Microstructure of Jameed at the end of

Storage Period

Differences between jameed samples at the end of storage

period could be visually observed in images obtained by

scanning electron microscopy (Figure 2).

From scanning electron microscopy, it is observed that the

protein structure was completely different among stored

jameed samples. In sample A (sheep buttermilk jameed), the

protein matrix became more large and compact with very

small spaces occupied by the fat globules. This probably

explained the harder texture as mentioned in Table 6. This

dense protein structure observed in sheep buttermilk jameed

may be due to the high protein content (Table 3). This is in

close agreement with the report of Ong et al. [23] who stated

that the microstructure of the gel of Cheddar cheese with

5.8% w/w milk protein was denser with smaller pores than

that with ~3.7%–4.8% w/w milk protein. This dense network

might arise due to the increased aggregation of casein

micelles. The high concentration of protein in the samples

decreased the mean free distance between casein micelles,

resulting in a densely aggregated casein micelles network.

In the scanning electron micrographs of sample B (goat

buttermilk jameed), the protein matrix was small and open as

compared with that of sheep buttermilk jameed. The numbers


of spaces occupied by the fat globules increased. With quite

dissimilarity, the image of cow buttermilk jameed (sample D)

showed the protein matrix as plates stacked over each other

with large pores filled with fat globules. Concerning the

microstructure of the jameed samples made from goat and

cow skim milk, the protein matrix characterized with coarse

structure especially in goat skim milk jameed. Small and

large void spaces, which are scattered uniformly over the

jameed matrix, can be observed, indicating the probable

location of fat globules within the matrix. Similar trend was

reported by Tsigkros et al. [24] who cleared that micrographs

of the Feta cheese samples containing 30% caprine milk

showed a marked difference from those of 100% ovine milk.

In particular, the casein network appeared to be less porous

and more aggregated. This would explain the increase in

cheese hardness observed in the 30% caprine milk feta

sample.

4. Conclusion

Jameed is usually made from sheep buttermilk but because

of shortage of sheep milk especially in summer and

increasing demand of jameed, our study tried to solve this

problem by using goat and cow buttermilk or skim milk in

jameed manufacture. However variation in chemical

composition and microbial properties, data of wetability and

textural characteristics indicated the possibility of making

jameed with good quality from goat and cow buttermilk or

skim milk.

Fig. 2. Scanning electron micrographs of jameed at the end of storage period.



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