cereal mixture

Inr. Dairy Journu/S

(1995) 109-12X

0 1995 Elsevier Science Lmited Printed in Ireland. All rights reserved 095%6946195IS29.00 ELSEVIER

Review Paper

Kishk-A

Dried Fermented Milk/Cereal Mixture A. Y. Tamime*

SAC-Auchincruive,

Food Science & Technology

Department,

Ayr, KA6 5HW, UK

&

T. P. O’Connor Department

of Food Chemistry, University College Cork, Cork, Republic

(Received

27 November

1993; revised version accepted

31 January

of Ireland 1994)

ABSTRACT Kishk is a driedfermented milk/cereal mixture which is produced in many countries. D(flerences in the chemical composition of commercial and laboratory-made samples are evident mainl,v because dtjferent ingredients have been used and the ratio of cereal to fermented milk ranges between I : 2 and 1: 4. Microbiologically, the product is free of cohforms, but may contain yeasts and moulds, depending on the hygiene during manufacture of the product. Sporeforming bacteria are the only organisms found in significant numbers. Kishks made with cereals other than wheat were highly rated by panelists, but Jlavoured Kishks were not accepted by Middle Eastern consumers. The product is highly nutritious and minor constituents that are defi’cient in milk are supplemented by cereal and vice versa.

INTRODUCTION

Traditional dried fermented milk products have been produced for centuries in many countries such as the Balkans, eastern Mediterranean, western Asia and Turkestan. Most of these products are home-made from whole milk (cow, sheep, goat or combinations of these) or from buttermilk. Nomads, desert dwellers and *To whom correspondence

should be addressed. 109

110

A. Y. Tamime, T. P. O’Connor

people in rural areas tend to preserve surplus summer milk as different products with extended shelf-life, examples of which are (a) concentrated and salted fermented milk preserved in animal skins; (b) similar to (a) but the product is made into balls and preserved in olive oil; and (c) numerous dried products (i.e. as powder or cobbles). The two former products have the characteristics of cheese, but the dried products are more popular owing to excellent shelf-life. The drying process is normally carried out in the sun. Information on the manufacturing and nutritional quality of indigenous fermented foods, including dried fermented milks, has been reported by van Veen & Steinkraus (1970), Hesseltine (1979), Wang & Hesseltine (198 l), Steinkraus (1983), El-Gendy (1983, 1986) and Jandal(l989). A recent textbook (Kurmann et al., 1992) provides an international inventory of fermented milk products (fresh and dried). Dried fermented milk products are popular in various parts of the world and can be important in the diets of these countries. These products may be prepared for eating in different ways: (a) reconstitution in a small quantity of water, followed by simmering gentle over a fire; when ready, this porridge-like product is normally consumed with bread; herbs and/or onions may be added; (b) as a powder to be used in soup preparations; (c) as biscuits to be eaten on their own or with tea; and (d) rehydration in large quantities of water and consumption as a beverage. The nutritional and other properties of fermented milk products are well established (IDF, 1983, 1984, 1988; Rennet-, 1983, 1991; Scott, 1989), but limited information is available on traditionally made dried fermented milk products. A dried yoghurt-cereal mixture, known as Kiskh, is a popular product in the Middle East. Recently, a research programme was commissioned in our laboratories to assess and evaluate the quality of Lebanese Kishk. The objective of this paper was to review Kishk in terms of definition, classification, methods of manufacture, and compositional and microbiological quality. Results of a study of 25 samples of Lebanese Kishk will be published separately.

NAMES AND CLASSIFICATION

OF KISHK

Throughout the region between the eastern Mediterranean and the Indian subcontinent, many names are applied to dried fermented milk products known as Kishk. Table 1 shows the variety of names by which this product is known in different countries. The exact origin of such names could be attributed to: (a) the region or area of manufacture, (b) the type of milk used, (c) borrowed or madeup names, (d) spelling according to region or country, and (e) the type of additive used. Thus, it is extremely difficult to find a common definition for Kishk which adequately covers all the products shown in Table 1, especially if the type of fermentation is unknown. It is therefore possible to suggest that the word ‘Kishk’ should be reserved for the product containing cereal, mainly parboiled cracked wheat (i.e. Burghol) or wheat flour. Other types of Kishk or closely related products could be classified as follows: (a) natural (with no additives) and (b) flavoured (with vegetables, spices, herbs or fruits). Kishk and related products, including products made in Iran and Saudi Arabia, are not considered to be dried yoghurt because the chemical composition, method of manufacture and method of utilisation are not similar to industrially manufactured dried yoghurt.

Ill

Kishk--a dried,fermented milk/cereal mixture

TABLE 1 Synonyms

for

Kishk

and

Related

have

been

Identified

Ingredientjadditiveh

Traditional Name Kishk, Kushuk. Keshkeh Kichk Burghul yoghurt Hogut Kishk Seiamy Zhum

Products that Countries”

or

Kushuk, Kushik Kashk, Kaskg Keshk Churpi, Zurpi Chum Trahana, Kapestoes, Tarhanocirv and Zamplaricos Korot Kurut Tschurra Madeer, Oggt and Oggtt Tamar Oggt Katyk Klila

Burghol, Bulgur, Bourghoul or Burgul’ Same as above Same as above Vegatables Wheat flour, garlic and pepper Wheat flour and herbs Herbs None None Wheat flour and tea Crushed wheat or flour, spices and vegetables Ascorbic sugar None None None Dates None None

acid. spices and

“Data compiled from Kosikowski (1982) Campbell-Platt Kurmann et al. (1992). ‘Major additives besides the salt added to fermented milk. ’ Parboiled cracked wheat.

PRODUCTION

AND CONSUMPTION

in Different

C’ounrr? Lebanon,

Syria and Egypt

Near East countries Qatar Egypt Yemen Iraq Iran Western Asia to Turkestan Nepal Nepal, Tibet and India Greece and Turkey

USSR Turkey Tibet Saudi Arabia Saudi Arabia USSR Algeria (1987)

FAO

(1990)

and

OF KISHK

Due to lack of data in most of the countries listed in Table 1, it is difficult to estimate the world production of Kishk and related products. These products are very popular locally, and some data on the consumption/production of Kishk have been reported:

(1) Iraq-in (2) (3)

the 1960s the estimated annual per caput consumption of Kishk in the northern region ranged between 20 and 30 kg (Platt, 1964; Kurmann et al., 1992). Turkey-Trahana, which is produced locally and is similar to Kishk (Table l), is consumed at a level of 8 kg per caput per annum (Platt, 1964). Lebanon-The average yearly production of Kishk is about 1000 tonnes (FAO, 1990).

112

A. Y. Tamime. T. P. O’Connor

If the trend in consumption and/or production of Kishk in all the countries between western Asia and Turkestan is similar to that reported in Iraq, Turkey and Lebanon, then the estimated world production of dried fermented milks containing cereal could be high. However, the pattern of food consumption in some countries is changing, and Kishk as a dish is becoming less common in the diet of the cosmopolitan consumer in the Lebanon and Jordan (Basson, 1981; FAO, 1990). Nevertheless, the nutritional value of Kishk is high and it still plays a major role in the diet of rural people, nomads and desert dwellers.

MANUFACTURING

PROCESS

The methods employed for the manufacture of Kishk may differ from one region to another because these processes are based on traditional systems, some of which are summarised in Table 2. Milks from different species (cow, goat, sheep, buffalo, camel) have been used for the production of Kishk. For example, Kishk from goat and buffalo milks is widely produced in Lebanon and Egypt, respectively, while camel’s milk products are widespread in North Africa. Although the word ‘milk’ is often used in the literature on Kishk-making (Table 2), skimmed milk or the buttermilk from churned fermented milk is normally used. Kishk with a high fat content does not store well since it is prone to oxidative rancidity. The cereal additive (i.e. parboiled cracked wheat) is known by different names such as Burghol, Bourghoul, Burghul or Bulgur. In the Lebanon, the method of preparation is as follows: soft wheat (varieties Stork, Jury, Italian and Salibi) is cleaned of stalks, dirt and other cereal grains by using a rotary cylindrical machine which is known locally as ‘ghorbal’ (Fig. 1). The same machine sizes the wheat kernels into three fractions: (a) large, (b) small and (c) broken. The large grains are steeped in boiling water for 1 h until soft, and then dried in the sun for 24 h. On the following day, the dried grains are moistened with water (-20%), cracked and dehusked. The Burgh01 is separated from the husk by winnowing (Fig. 2), and later sized as coarse or tine. It is recommended that coarse Burgh01 be used for Kishkmaking. Thus, the handling and processing stages of Burgh01 are shown in Fig. 3. Traditionally, Lebanese Kishk is made from goat’s milk and commercial production (S. Najar, pers. comm.) is as follows. Milk is boiled, cooled and fermented using a starter culture or the previous day’s yoghurt. The ratio of Burgh01 to yoghurt is I : 4, and salt is added at a level of 6% (w/w). The yoghurt is added to the Burgh01 in small proportions for up to 6 days, and the mixture is kneaded daily. The temperature is maintained at -35°C in order to complete the fermentation and achieve proper hydration of the Burghol. Afterwards, the fermented milk-cereal mixture is formed into small balls or nuggets, placed on trays or concrete roofs and dried in the sun for 7-8 days. The dried Kishk is then milled to a powder at graneries and either packed into cloth, plastic bags or large bins (Fig. 4).

CHEMICAL

COMPOSITION

There are major differences in the chemical composition of commercial samples of Kishk made in different Middle Eastern countries: 3-g-13.0% moisture, 8.954.5% protein, l&19.9% fat, 31.0-65.7% carbohydrates, 0.5--2.5% tibre and

Kishk-a

dried,fermented milk/cereal mixture

113

3.8-9.5% ash (Table 3). These differences are due to: (a) inherent differences between the traditional methods of manufacture (Table 2) and the efficiency of fat separation after churning the fermented milk; (b) some products being made exclusively from milk without addition of cereals and containing >35% protein; (c) different proportions of Burghol, fermented milk and salt; (d) the use of strained yoghurt (-26% TS) rather than buttermilk (i.e. churned yoghurt -10% TS)- -addition of the Burgh01 to fermented milk at the same ratio (1 : 4) will produce Kishk high in protein and low in carbohydrates; (e) the use of different multiplication factors (6.25 or 6.38) to calculate the protein content in the product from the nitrogen content; and (f) the data in Table 3 being expressed as a percentage on either a wet- or dry-weight basis. In view of the wide variation in the moisture content of Kishk (3.9-13.0%) it is recommended that for comparative purposes the components of Kishk should be expressed as a percentage on a dry-weight basis. It is evident from the data in Table 3 that samples of Kishk with a high content of carbohydrates and an appreciable amount of fibre are made with Burgh01 or wheat flour. Conversely, the Iranian Kishk had the highest content of protein (54.4%) because it was made from milk and herbs only without added Burgh01 (Kosikowski, 1982). Since the late 1970s Kishk has stimulated some interest among scientists in different laboratories around the world, and the research objectives have included the following: (a) the replacement of Burgh01 with other cereals, such as rice, maize or chick-pea flours, (b) the use of fresh milk (goat, sheep or cow) or reconstituted skimmed milk powder, (c) the use of a soy- or whey-based medium for the production of Kishk, and (d) the use of different and pure starter cultures for the fermentation. A summary of the chemical composition of laboratory-made Kishk samples is shown in Table 4. The moisture, protein, fat, carbohydrate and ash contents were similar to those for commercial Kishk products (Table 3). However, the protein content was >19% in some samples due to two main factors: (a) addition of chick-pea or soy bean flours, which contained -24 and 40% protein, respectively (Hafez & Hamada, 1984; Hassan & Hussein, 1987) compared with -11% in Burgh01 (Cadena & Robinson, 1979; Hafez & Hamada, 1984); it is recommended to heat-treat soy beans in an alkaline solution before addition to milk to inactivate trypsin inhibitor and any other anti-nutritional factors present (Hafez & Hamada, 1984) and (b) products such as Madeer and Oggt, which are made exclusively from milk without the addition of cereal, have protein contents ranging from 27 to 40% (Tables 3 and 4). Different drying techniques were used in the manufacture of laboratory-made Kishk. Salama et al. (1992) spread the yoghurt/cereal mixture on mats and dried it at 32°C for 5 days. Air-drying at temperatures ranging from 43 to 55°C up to 46 h was used by Hamad & Fields (1982) Hafez & Hamada (1984) Hassan & Hussein (1987) and Abou-Donia et al. (1991). Freeze- and roller-drying were used by van Veen rt (11.(1969), Robinson (1978) and Robinson & Cadena (1978). However, for the manufacture of Oggt and Madeer, the fermented milk was concentrated by: (a) heating with continuous stirring; and (b) salting (10% (w/w)) followed by removing whey by filtration through a cloth bag. The dough-like product was later dried in the sun for 24 days (Sawaya et al., 1984) or by fandrying at room temperature or at 45°C overnight (Al-Ruqaie et al., 1987) or in a vacuum oven at 45°C for 8-10 h (Al-Mohizea et ul., 1988).

Methods

NR

1: 2 or more

Mix salted and/or fermented buttermilk with wheat flour or Burgh01 in a jar and leave for few days; dry in the sun and grind to a powder; sometimes sour dough is used instead of Burghol. the buttermilk in a Burgh01 in water, small cakes by bag.

1:4

Mix two parts yoghurt with one part whole-wheat meal (possible Burghol) and ferment for a week; add Labneh from equivalent volume of the added yoghurt and ferment for a further 4-5 days; sun dry and grind to a powder.

Churn the Leben (20 kg) in a goat’s skin bag and concentrate cloth bag or by sedimentation in a glazed clay pot; cook the mix with strained buttermilk and salt; shape the mixture into hand, dry for 45 days in the sun and store in a loose woven

NR

Ratio”

Middle

van Veen et al. (1969)

Basson & Abuirmeileh (1980)

-

Platt (1964)

El-Sadek et al. (1958) and El-Gendy (1983)

(1957)

References

Countries

Garnier

Eastern

Tomato paste, red pepper, chopped onionsd

Spices

-

Additivesb

of Kishk in Different

Moisten slightly parboiled crushed wheat grains with salted boiled water; dilute concentrated buttermilk (known in Egypt as Laban Zeer) with water and raw milk and mix with cereal until a thin creamy consistency is obtained, leave for 24 h to allow further fermentation, mix thoroughly, form into irregular small pieces, place on straw mats and dry in the sun for 2-3 days; store in traditional mud chambers similar to those used for storing wheat grains.

TABLE 2 for the Manufacture

NR

Employed

Add Burgh01 (parboiled cracked wheat) to earthenware pot known as ‘maajen’ and a small amount of boiling water to burst the grain, drain and dry in sun for S-6 h; the cereal paste is laid on a tray and mixed with Leben (yoghurt), Labneh (strained yoghurt) and salt to obtain a homogeneous mass which is placed in ‘maajen’; every second day Leben, Labneh and salt are added and mixed; after 15 days the fermentation is complete and the product is cut into pieces which are exposed for 7-8 h in the sun; the product is then milled, sieved, dried further in the sun and packed in glass jars.

Processing Stages

Details of Some Traditional

a

cb N

$.

6

NR

1 : 2.5

I:2

Similar to the process described by El-Sadek ct al. (I 958), but differs at the following stages: (a) twice the volume of diluted buttermilk is also added after 24 h fermentation followed by kneading and fermentation for a further 24 h: (b) the sun-dried Kishk is subsequently oven-dried.

Mix 5 kg Burgh01 with 10 kg pasteurised milk (cow. sheep or goat) in an earthenware jar for 24 h at room temperature; add 2-2.5 kg yoghurt. mix and ferment for 48 h; spread in a thin layer, sun dry and grind to a powder.

Mix Burgh01 or wheat flour to yoghurt or naturally fermented milk and add 3% salt; leave for 24 h to ferment in a warm place, form into small balls, sun dry for 7 days on straw mats and grind to a powder.

“Ratio of Burgh01 (cracked wheat): fermented milk. ‘The additives are optional. ‘Not reported. “Such additives are only used in Turkey during the preparation of Trahana

(see Table 1).

Oggtt is made from goat’s or camel’s milk which is allowed to sour naturally for for I-2 days; churn the milk. remove coalesced butter granules and process as follows: (a) boil buttermilk while stirring until it thickens, cool to 30-35C. shape into cakes. press on the tent cloth and sun dry; or (b) add 10% salt. drain using a cloth bag. shape into cakes and dry in the sun.

1:4

Soak the Burgh01 in goat’s milk yoghurt overnight: add salt. pass through a meat mincer. leave for 7-8 days and knead daily: form into small pieces. place on trays. sun dry and grind to a powder. Spices

-

et al. (1987)

( 199 1)

Al-Ruqaie

Dagher

FAO (1990)

Farr (1982)

FAO ( 1982)

$ 3 ~

116

A. Y. Tamime. T. P. O’Connor

Fig. 1. View of a rotary cylindrical

Fig. 2. Illustration

of a traditional

machine

for cleaning

winnowing technique cracked wheat grains.

and sizing the wheat kernels.

to separate

the husk from the

Fig. 3. Illustration showing Burghol at some stages during production. A: clean and large what grains; B: parboiled and dried grains; C and D: fine and coarse Burghol, respectively.

Fig. 4. Examples of Kishk at the principal stages of manufacture. A: yoghurt:Burghol mixture: B: small balls or nuggets of dried Kishk; C: Kishk powder.

-

37.3 35.5 1.8

0.5’

58.8 36.9 -

1.8

2.2 2.2 0.7

2.5

59.0 -

65.7 45.8 31.0 65.3 -

-

Fibre

-

Carboyhydrate

3.8 8.1 2.0 3.3 11.6 7.6 9.1 6.7 9.5 6.4 6.4 11.1 7.9 7.6 6.5 7.1 5.6 -

Egypt6

6.4 -

Lebanon I Egypt” Saudi Arabid’ Saudi Arabia Saudi Arabia

Iraq‘ Irand Egypt’ Cyprus > Iraq Saudi Arabia1 -.s > Egypt -

Country

Ash

>

& Steinkraus (1977)

(1984)

Dagher ( 199 1)

Al-Ruqaie et al. (1987)

Atia & Khattab (1985) Salji (1986) Al-Mashhadi et al. (1987)

Abou-Donia

FAO (1982)

Robinson & Cadena (1978) El-Erian (1979)

Economidou

El-Sadek et al. (1958) Frankul & Pellett (1959) von Taleban & Renner (1972) Morcos et al. (1973)

References

TABLE 3 (g 100 g-‘) of Different Commercial Kishk and Related Products

‘Not reported. bAverage of eight samples-data calculated on dry-matter basis. ‘Data calculated on dry-matter basis. ‘Average of 135 samples. ‘Average of five samples. !Average of 18 samples. gAverage of 14 samples. ‘Average of 10 samples. ‘Impurities. jAverage of three samples. Note: The Iranian and Saudi Arabian products do not contain any added cereal.

5.5 9.1 8.3 8.9 8.0 13.0 9.6 3.9 8.2 7.5 5.4 13.0

18.5 2.9 7.0 1.6 6.9 11.9 7.4 15.3 13.4 18.9 19.9 11.9

6.9 8.6 7.9 6.9 16.1 I.2

13.4 17.4 54.4 23.5 20.8 17.8 29.4 45.8 13.2 16.7 8.9 13.4 15.9 15.8 355 36.4 30.4 32.4 15.9

8.0

7.4 4.4 78 5.5 8.3

Fat

Protein

Moisture

Proximate Chemical Composition

3. 3 cp 7 ? 0 cj 9 5

4

$

15.3 28.9 28.6 8.8-26.4 15841~1 -

0.5’

-

0.8-2.6 242.7

2.2

-

Fihre

7.9 5.3 5.3 6.2-7.7 5.5-8.3

3.5-5.3

-

3.64.9 4.34.7 8.7-9.9

2.3 25 -

-

Ash

N/A N/A

N/A” N!A N/A

I:2

I : 1.5-2

I:2

I:2 1:3 I:3 I:2 1:2 I : I.5 10% 1:2

Rate of addition’

TABLE 4 (g 100 g-‘) of Laboratory-made

None None None None None

B

1 1 \ I

B B, WF, CF

B WF, MF WF B B B, WF, CF WF’, RF’, MF’ WF

Additiveh

Kishk and Other Rejkwwes

Products

& Fields (1982)

Al-Mohizea

Al-Ruqaie

et al. (1988)

rt al. (1987)

Sawaya et al. (1984)

Hamad

Hafez & Hamada (1984) Hassan & Hussein (1987)

Frankul & Pellett (1959) Robinson & Cadena (197X) Cadena & Robinson (1979) Hamad & Fields (1982) Hafez & Hamada (1984) Hassan & Hussein (1987) Abou-Donia et al. (1991) Saiama et al. (1992)

Related

“Ration of additive : fermented milk or O/o(w/w). “B: Burghol; WF: wheat flour: MF: malted flour: CF: chick-pea flour: RF: rice flour: MF: maize flour. ‘Data calculated on dry-weight basis. “Not reported. “And combinations of these cereal flours. ‘Impurities. “Not applicable. “Goat’s milk. ‘Cow’s milk. ‘Sheep’s milk.

2. Madeer and Oggt 3.9 35.5 6.9” 26.3 7.2’ 26.6 3.7-8.3‘ ’ 27.2-34.4 3.5_8.l”/ 33.2-40.5

whey 13.3

Fermented 9.7

36.9 34.9 33.4 40.2-48.7 20.2-35.4

56.3-62.6

0.7-I .8

1.884.6

70.6 -

-

Carbohydrate

Composition

1.7

II.1

Fat

milk +/or soya milk 16.1-17.2 18.3-28.2

19.7 18.3 17.1 14.6 14.9 16.77258 17.5-19.3 16.8-17.9

milk

Protein

Fermented 9.1-9.2 5.2-9.9‘

1. Kishk Fermented 5.2 6.0 9.4 9.5 52-8.0 12.0-13.0 94-9.7’

Moisture

Range of Means of the Chemical

_ Z

2 s i 2 2 3 7’ c, 2 2

$ .$ ; 2 2

d

3 $

120

A. Y. Tamime, T. P. O’Connor

NUTRIENTS

IN KISHK

The major constituents of some commercial and laboratory-made samples of Kishk are shown in Tables 3 and 4. The mean concentrations of some minerals in Kishk are compared with skimmed milk powder and Burgh01 in Table 5. Some commercial and laboratory-made Kishk samples contain appreciable quantities of phosphorus (350-410 mg 100 gg’), and the phosphorus content of most of the samples was similar to Burghol, with the exception of one sample. The phosphorus content of Kishk is -50% below that found in skimmed milk powder; however, Madeer, which is made completely from milk, had a phosphorus content similar to that in milk powder (i.e. -100% retention). Concentrations of calcium and magnesium were generally low in both types of Kishk, with the exception of Lebanese Kishk which contained 60 mg Ca 100 g-r (Table 5). This could be attributed to the ratio of Burgh01 to yoghurt used (i.e. I : 4 compared with 1: 2 for Kishk made in Egypt or Iraq). Among the other elements, the concentration of iron in Kishk was significant (34 mg 100 gg’) for a milk-based product. Soy bean and chick-pea flours are good sources of iron, and, according to Hassan & Hussein (1987) fortification of yoghurt with soy milk and chick-pea flour during the manufacture of laboratory-made Kishk increased the iron content of the product significantly (Table 5). The level of salt (NaCI) in Kishk varied between 1.O and 8.4% (El-Sadek et al., 1958); this variation is due to the addition of different amounts of salt during preparation of the product. The salt in Kishk is used as a preservative and as a flavour enhancer, but has possibly dietary implications (e.g. it could be a contributory factor in high blood pressure). Since Kishk is normally used to prepare a wide range of dishes, reduction in the salt level of this product may not be necessary because little or no salt will be added by the housewife. Kishk may be a good source of certain B vitamins, but it is deficient in vitamin C and some fat-soluble vitamins which are lost during manufacture. Niacin is the only vitamin whose concentration is -3.5-fold higher in Kishk than in skimmed milk powder (Table 6). This is due to (a) the activity of microorganisms during fermentation of the milk-Reddy et al. (1976) reported that yoghurt starter culture actively synthesises folic acid and niacin during the fermentation of milk; and (b) the fact that Burgh01 also contains an appreciable amount of niacin (Table 6). Kishk made with tomato had an improved flavour after reconstitution and boiling (van Veen et al., 1969). The tomato-flavoured Kishk contained higher concentrations of riboflavin and pro-vitamin A than samples of ordinary Kishk. The protein content of some types of Kishk is very high and hence the amino acid content is excellent (Table 7). Kishk contains high concentrations of phenylalanine, threonine, isoleucine, leucine, arginine, valine, tyrosine and lysine, but it has low amounts of tryptophan and sulphur-containing amino acids. Comparison of the amino acid content of Kishk with the provisional pattern suggested by FAOjWHO (1985), showed that the tryptophan of Kishk was a limiting factor (Morcos et al., 1973). These authors attributed the loss to decomposition of tryptophan during the fermentation and sun-drying stages. However, Kishk produced under laboratory conditions had a tryptophan content similar to that suggested by FAOjWHO (1985) (Cadena & Robinson, 1979; Saway et al., 1984).

milk powder

30 41

1280

4.1 3.6

0.27

3.1 5.1 6.1 9.6 14.5 6.4 1 I.0 Il.3 9.0 10.7 12.4 2.5

38 3.9 3.3 2.3 3.1

‘

121.4

-

130.0

114.8 1IO.6 141.0

I IO.1

53.8 51.5 116.1 115.6 116.1 114.2 115.5 114.7

-

-

3.2”

Tr’

2.3’ 2.7 2.0’ 4.1 I.0 3.0 I.0 2.0 2.0 2.1 I.0 0.1

TABLE 5 (mg 100 g-‘) of Some Minerals Dried Products

& Hussein

C/ nl. (1991)

(1987)

“For further

Watt & Merrill (I 963) Hassan & Hussein (1987)

Holland

Saway c’t ul. (1984)

Hassan

Salama et al. (1992)

Abou-Donia

(1984)

er al. (1973)

FAO (I 982)

Morcos

details refer to Table 3. ‘Not reported.

None

None

B B WF-M -SM -M+SM B -M -SM -M+SM CP -M -SM -M+SM None

in Different

“B: Burghol; WF: wheat flour; M: milk: SM: soy milk: CP: chick-pea flour. ‘For further details refer to Table 4. “Data calculated on dry-weight basis. ‘Trace.

4. Burghol 319

3. Skimmed 970

957

-

-

55 155 142 38 600

Kishk” and Madeer” 109 131 86 78 79 88 80 82 134 121 129 982

Kishkh

2. Laboratory-made 31s 359

403 242 350

I. Commercial 410

Mean Concentration

122

A. Y. Tamime. T. P. O’Connor

TABLE6 Mean Concentration Thiamine

(mg 100 g-‘) of Some B Vitamins in Different Dried Products Niacin

Rihqflavin

References

I. Commercial Kishk” h

3.7 3.5 2.9 3.4 3.2 > - >

0.09 0.14

3.2 3.4 >

Hamad & Fields (1982)

Madeer 0.40

2.57

Sawaya et al. (1984)

Skimmed milk powder 1.63 0.38

1.0

Holland et al. (1991)

Burghol 0.30

4.2

Watt & Merrill (1963)

0.21 0.06 0.37 0.14 -

2. Laboratory-made -

3.

4.

5.

El-Sadek et al. (1958) Frankul (1961) Robinson & Cadena (1978)

0.26 0.05 0.40 0.09 0.25 0.18 0.07

-

Laboratory-made 0.24

FAO (1982) Abou-Donia

(1984)

Kishk

0.10

“For further details refer to Table 3. ‘Not reported. Thus, the net protein utilisation between 59 and 76%, which is similar 1973; Cadena & Robinson, 1979). It milk protein that makes up the amino good source of iron, which is deficient

of Kishk in animal experiments ranged to casein (Frankul, 1961; Morcos et al., is evident that Kishk is a good source of acids deficient in cereals, but Burghol is a in milk.

MICROBIOLOGICAL

QUALITY

The microbiological quality of Kishk (commercial and laboratory-made) and Madeer varied widely (Table 8), which reflects the hygiene during production. The acidic nature of these products, coupled with a low moisture content and the presence of salt, means that coliforms and Stapfylococcus aureus were not detected in the samples shown in Table 8. Atia & Khattab (1985) detected faecal streptococci (possibly, Enterococcus fiecium) in only one out of eight samples of Kishk tested (at a level of 3.4 x 16’ colony-forming units (CFU) g-‘). These authors attributed the presence of this organism in the Kishk sample to its high pH (4.70 compared with an average of 4.17 for the other samples), and its low salt content (4.15 compared with 8.9%).

Kishk--N

Amino Amino ucids

Try Thr Ile Leu Lys Met CYS Phe Tyr Val Arg His Ala Asp GILI Gly Pro Ser

dried,fermented

milklcereul

TABLE 7 (mg g-’ N) of Kishk and Burghol”

Acid Contents

Kishk ”

Truhunu’

A

B

A

B

61 205 212 512 324 I21 107 314 261 326 313 167 235 375 1563 217 745 299

65 220 1050

58 149 235 465 300 I12 I7 299 174 238 312 176 217 334 1437 211 539 259

61 184 223 441 214 II5 I4 288 I87 243 345 144 218 360 1569 138 569 287

310 120 II0 310 255 335 310 155 I/ _

123

miuturc

Mudeer

Burghol

FAO/ WHO refiwnw

74 344 298 623 444 176 54 314 261 430 I84 I61 204 470 1423 II4 793 330

45 172 195 390 160 90 123 253 I83 230 270 I20 222 290 1397 241 637 260

250 180 576 270 144 126 I80 180 270

“Data compiled from Jamalian & Pellett (1968) Morcos et al. (1973). Economidou & Steinkraus (1977) and Sawaya et (11.(1984). “A and B are Lebanese and Egyptian samples, respectively. “Trahana made with wheat (Durum variety) and sheep’s milk fermented with a yoghurt starter culture; A and B are traditional and commercial samples. respectively. “Not reported.

The samples reported in Table 8 contained two main groups of organism. ElSadek et ul. (1958) found that 57-75% of the total counts were spore-formers (Bucillus lichen[formis, Bacillus suhtilus and Bacillus megutherium) while other organisms, including lactic acid bacteria, constituted 25543% of the total bacterial flora. The same authors reported that the eight Kishk samples contained a very low number of yeasts. Spore-formers, such as B. suhtilus, Bacillus polymy.ua. Bacillus cougulans and Bacillus cereus, were present in Egyptian Kishk because the product is dried in the oven before storage, and these organisms can tolerate high drying temperatures (Atia & Khattab, 1985). It is generally considered that high counts of lactic acid bacteria in Kishk contribute to the safety of the product during manufacture and storage; however, these organisms will be killed when the Kishk is cooked. Proteolytic and salt-tolerant microorganisms have been detected in appreciable numbers (-3.9 x IO6 CFU gg’) in samples of Egyptian Kishk (Atia & Khattab, 1985). There is no information in the literature on the starter culture(s) used in the preparation of Kishk. In the traditional method of manufacture. the fcrmen-

A. Y. Tamime. T. P. O’Connor

124

Microbiological

TABLE 8 Quality (CFU g-l)” of Different Samples of Kishk and Madeer

Total Count

Lactic acid

Yeasts and moulds

References

1. Commercial samples 2.9 x 103-1.1 x IO5

-

0.3 x lo’-2.6 x 10’ 3.7-7.2 x lo6 1.9 x 104-8.0 x lo5

4.5 x 103-7.8 x lo4

2.0 x 102-6.5 x lo3 El-Sadek & Mahmoud (1958)
2. Laboratory-made < 10 x lo3 1.8-2.0 x lo3

6.4 x 106-2.2 x IO’


x lo2

Cadena & Robinson (1979) Salama et al. (1992)

“Colony forming units.

tation of the milk is achieved by indigenous microflora, or the addition of fermented milk from the previous day’s production. Thus, it may be assumed that undefined starter cultures have traditionally been employed to manufacture this product. In most of the samples of experimental Kishk shown in Table 4, Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus were used to ferment the milk. No improvement in the quality of Kishk was observed when Lactobacillus acidophilus or Lactobacillus casei subsp. casei was added to the yoghurt starter culture (Abou-Donia et al., 1991). Mesophilic lactococci and Leuconostoc spp. were used during the manufacture of Oggt (Al-Mohizea et al., 1988) while Sawaya et al. (1984) allowed the milk to undergo natural fermentation for the production of Madeer by a method similar to the traditional method used by the desert dwellers. A different type of Iraqi Kishk, which is not included in Tables 1 and 2, is made in earthenware jars using de-hulled wheat kernels and chopped turnip in a ratio of 3 : 1, Sour dough is mixed with water, added to this mixture which is then covered and allowed to ferment (Alnouri et al., 1974). The microorganisms from the turnip and sour dough convert the sugars derived from the starches by amylolytic enzymes to lactic acid. The Kishk is strained, eaten as porridge or cooked with vegetables while the extracted filtrate is used for the preparation of soups. Thus, controlled fermentation was achieved by using pure single-strain cultures (Lactococcus lactis subsp. lactis, Lactobacillus plantarum, Saccharomyces rouxii, yoghurt starter culture or combinations of these) (Alnouri et al., 1974). The mixed culture consisting of lactococci, lactobacilli and yeast was highly recommended by the same authors, and fermentation was achieved within 24 h. According to Alnouri et al. (1974), the industrial production of such a product could be achieved by using pure starter cultures and replacing the wheat kernels with flour, which will allow the fermented product to be drum-dried easily.

Kishk-a

dried,fermented milk/cereal mixture

SENSORY

125

PROPERTIES

Different sensory schemes have been used to evaluate the properties of laboratory-made Kishk. The sensory attributes were found to be different and could be related to the method used to prepare the Kishk as a dish. Most of the work was conducted by Egyptian and Saudi Arabian scientists; the scoring systems for sensory attributes were as follows: (a) colour, consistency and flavour---scored out of 10 points (Salama et al., 1992); (b) acceptability, taste, odour, sourness, appearance, colour and texture-scored out of 10 points (Hassan & Hussein. 1987); (c) flavour (45 points), body and texture (30 points), appearance (15 points) and acidity (10 points) (Abou-Donia et al., 1991); (d) colour, odour, taste, texture and overall acceptability, evaluated on a nine-point Hedonic scale by AlMohizea et al. (1988); and (e) the acceptability attribute only, evaluated on a tivepoint Hedonic scale by Al-Ruqaie rt al. (1987). Oggtt made from cow’s milk was superior to that made from sheep’s milk (AlMohizea et al., 1988). The same product, made from goat’s, cow’s or reconstituted skimmed milk powder, was acceptable to the panellists, but the flavoured Oggtts (chocolate, coffee, mint, orange, pineapple or strawberry) were not popular, with the exception of ‘date’ flavour (Al-Raqaie et al., 1987). Analysis of variance for colour and consistency of Kishk samples made from skimmed milk or Laban Rayeb showed no significant difference, but the flavour was significantly higher (P < 0.05) for the product made from skimmed milk (Salama et al., 1992). Replacement of cow’s milk with soy milk, or using a mixture of equal proportions of soy milk and skimmed milk in the production of Kishk from Burgh01 or chick-pea, significantly increased the acceptability of the product (Hassan & Hussein, 1987). Abou-Donia et ul. (1991) concluded that Kishk made with rice flour and/or crushed wheat and rice was highly acceptable. By substituting maize flour for rice flour in Atole (a Mexican gruel food), and adding a yoghurt-like product, gave a preparation that was readily accepted by Mexican mothers and children. Strawberryand vanilla-flavoured gruels proved most popular (Cadena & Robinson, 1979).

CONCLUSION Kishk has good compositional, nutritional and microbiological qualities. Fermenting milk makes it easier to digest and the presence of fibre is in accord with current thoughts on good nutritional practice. There are likely to be limitations for flavouring Kishk with added fruits and sugar for customers in the Middle East, but such modification of Kishk for European and North American markets may prove more acceptable, in the same way that flavoured yoghurt has gained considerable appeal.

ACKNOWLEDGEMENT SAC receives financial support eries Department (SOAFD).

from the Scottish

Office of Agriculture

and Fish-

126

A. Y. Tamime, T. P. O’Connor

REFERENCES Abou-Donia,

S. A. (1984). Egyptian fresh fermented milk products. N. Z. J. Dairy Sci.

Technol., 19, 7-18.

Abou-Donia, S. A., Attia, I. A., Khattab, A. A. & El-Shenawi, Z. (1991). Formulation of dried cereal fermented milks with prolonged storage life. Egypt J. Dairy Sci., 19, 283-99.

Al-Mashhadi, A. S., Saadi, S. R., Ismail, A. & Salji, J. P. (1987). Traditional fermented dairy products in Saudi Arabia. Cultured Dairy Products J., 22(l), 24-33. Al-Mohizea, 1. S., Abu-Lehia, I. H. & El-Behery, M. M. (1988). Acceptability of laboratory made Oggt using different types of milk. Cultured Dairy Products J., 23(3), 20-3.

Alnouri, F. F., Duitschaver, C. L. & de Man, J. M. (1974). The use of pure cultures for the preparation of Kushuk. J. Inst. Can. Sci. Technol. Aliment., 7,228-9. Al-Ruqaie, 1. M., El-Nahhal, H. M. & Wahdan, A. N. (1987). Improvement in the quality of dried fermented milk product, Oggt. J. Dairy Res., 54, 429-35. Atia, I. A. & Khattab, A. A. (1985). Microbiological and chemical studies on Kishk. Alex. Sci. Exch., 6, 63-71.

Basson, P. (1981). Women and traditional

food technologies:

Changes in rural Jordan.

Ecology Food Nutr., 11, 17-23.

Basson, P. & Abuirmeileh, N. (1980). Food Conversation in North- West Jordan. Report submitted to Food and Agriculture Organization ofthe United Nations, Rome, Italy, p. 27. Cadena, M. A. & Robinson, R. K. (1979). The acceptability of yoghurt-cereal mixtures to a rural community in Mexico. Ecology Food Nutr., 8, 169-74. Campbell-Platt. G. (1987). Fermented Foods qf the World. Butterworths, London, UK, p. 104. Dagher, S. M. ed. (1991). Traditional Foods in the Near East. Food and Nutrition Paper no. 50, Food and Agriculture Organization of the United Nations, Rome, Italy, pp. 60-2. Economidous, P. L. & Steinkraus, K. H. (1977). Greek trahanas, Symposium on Indigenous Fermented Foods-Thailand. Cited by Steinkraus (1983) pp. 274-5. El-Erian, A. F. M. (1979). Studies on Oggt. Proceedings of the 3rd Conference of the Saudi Biological Society, King Faisal University, Riyad, Saudi Arabia. El-Gendy, S. M. (1983). Fermented foods of Egypt and the Middle East. J. Food Protection, 46, 358-67.

El-Gendy,

S. M. (1986). Fermented

Fermented Food

qf Non-Western

foods of Egypt and the Middle East. In Indigenous Origin, ed. C. W. Hesseltine & H. L. Wang. J. Crea-

mer, Berlin, Germany, pp. 169-92. El-Sadek, G. M., Zawahry, M. R., Mahmoud, S. A. Z. & Abd El-Motteleb, L. (1958). Chemical composition of Egyptian Kishk. Indian J. Dairy Sci., 11, 67-75. FAO (1982). Food Composition Tables for the Near East. Food and Nutrition Paper no. 26, Food and Agriculture Organization of the United Nations, Rome, Italy, pp. 100-3, 226, 231. FAO (1990). The Technology of Traditional Milk Products in Developing Countries. Animal Production and Health Paper 85, Food and Agriculture Organization of the United Nations, Rome, Italy, pp. 51, 315. FAO/WHO (1985). Energy and Protein Requirements. Technical Report Series no. 724, World Health Organization, Geneva, Switzerland, pp. 64-6. Farr, D. (1982). Traditional fermented foods: A great potential for the future. In Nest& Research News 1980/81, eds. C. Boella. Nestle Products Technical Assistance Co. Ltd, La Tour-de-Peilz, pp. 31-7. Frankul, W. (1961). Problems of some solutions: Iraq. Proc. Nutr. Sot., 20, 102-5. Frankul, W. & Pellet& P. L. (1959). The nutritive value of kushuk-An Iraqi fermented milk/wheat product. Proc. Nutr. Sot., 18, xxxvi-xxxvii.

Kishk -a

dried,fermented

milklcercvd mi.utuw

127

Garnier, M. (1957). Les Produits Laitiers du Lihan et de la Syrie-Etude Biologiyue et Vituminologiyue. Vigot Frires, Paris, France, pp. 137-8. Hafez, Y, S. & Hamada, A. S. (1984). Laboratory preparation of soy-based Kishk. J. Food sci., 49. 197-8. Hamad, A. M. & Fields, M. L. (1982). Preliminary evaluations of new type of Kishk made from whey. J. Food Sci., 47, 1140-2. Hassan, E. M. & Hussein, W. A. (1987). Chemical, nutritional and sensory evaluation of different Kishk mixtures. Egypt J. Food Sci., Special Issue, 13746. Hesseltine, C. W. (1979). Some important fermented foods of mid-Asia, the Middle East and Africa. J. Am. Oil Chwn. Sac.. 56, 367-47. Holland. B.. Welch, A. A., Unwin, I. D., Buss. D. H., Paul. A. A. & Southgate, D. A. T. (I 99 I). Mc,Cunce und Widdowson Ip-Thc Composition of’ Foods, 5th revised and extended edition. The Royal Society of Chemistry, Cambridge, pp. 24-7, 78 -81. IDF (1983). Cultured Dairy Foods in Human Nu/rition. Bulletin No. 159, International Dairy Federation, Brussels. IDF (1984). Fermented Milks. Bulletin No. 179, International Dairy Federation, Brussels. IDF (1988). Fermented Milks-Science and Technology. Bulletin No. 227, International Dairy Federation, Brussels. Jamalian. J. & Pellett, P. L. (1968). Nutritional value of Middle Eastern foodstuffs -IV. Amino acid composition. J. Sci. Food Agric., 19, 378S82. Jandal, J. M. (1989). Kishk as fermented dairy product. Indian Dairp~un, 41, 479-48 1. Kosikowski, F. V. (1982). Cheese mnd Fermented Milk FootIs, 2nd edn., F. V. Kosikowski & Associates, New York, pp. 68-71. Kurmann, J. A., Rasic, J. Lj. & Kroger, M. (1992). Encylopedia of’Fermentet/ Fresh Milk Produc.ts. Van Nostrand Reinhold, New York, pp. 81-287. Morcos, S. R., Hegazi, S. M. & El-Damhougy, S. T. (1973). Fermented foods in common use in Egypt- I. The nutritive value of Kishk. J. Sci. Food Agric., 24, 1153-6. Platt. B. S. (1964). Biological ennoblement: Improvement of the nutritive value of foods and dietary regimens of biological agencies. Food Technol., 18, 622-70. Reddy, K. P., Shahani, K. M. & Kulkarni, S. M. (1976). B-Complex vitamins in cultured and acidified yogurts. J. Dairy Sci.. 59, 191 -5. Renner, E. (1983). Cultured milk products and butter. In Milk and Dairy Products in Human Nutrition. Volkswirtschaftlicher Verlag, Munich, pp. 323-5 I. Renner. E. (1991). Cultured Dairy Products in Human Nutrition-Dietary Calcium and Health. Bulletin No. 255, International Dairy Federation, Brussels, pp. 2-24. Robinson, R. K. (1978). Improving the image of yoghurt&cereal mixtures. S. A,fb. J. Dtrir>x Twhnol., 10, 139 41. Robinson, R. K. & Cadena, M. A. (1978). The potential value of yoghurt-cereal mixtures. Ecology Food Nutr., 7, 131-6. Salama. A. A., Damir. A. A. & Mohamed, M. S. (1992). Effect of cooking on nutrients. microbial and sensory properties of skimmed milk and Rayeb Kishk. Acta Aliment., 21 (I). 67-76. Salji, J. P. (1986). Fermented dairy products of Saudi Arabia. Cultured Dairy Produc.t.s J.. 21 (3), 6 -7. Sawaya, W. N., Salji. J. P., Ayaz, M. & Khalil. J. K. (1984). The chemical composition and nutritive value of Madeer. Ecology Food Nutr.. 55. 29.~37. Scott, K. J. (1989). Micronutrients in milk products. In Micronutrients in Milk and Milk-Based FOOT Products. ed. E. Renner. Elsevier Applied Science, London, UK, pp. 71-123. Steinkraus. K. H. ed. (1983). Hundhook of’ Indigenous Fermented Foods. Marcel Dekker Inc., New York, USA, pp. 244-99. van Veen, A. G. & Steinkrdus, K. H. (1970). Nutritive value and wholesomeness of fermented foods. J. Agric. Food Chem., 18, 576--8. van Veen. A. G., Graham, D. C.W. & Steinkraus, K. H. (1969). Fermented milk--wheat combination. Trap. Geogr. Med., 21 (3), 47-52.

128

A. Y. Tamime, T. P. O’Connor

von Taleban, H. & Renner, E. (1972). Untersuchungen fiber Kashk-ein milchprodukt in Iran. Milchwissenschaft, 27, 753-6. Wang, H. L. & Hesseltine, C. W. (1981). Use of microbial cultures: Legume and cereal products. J. Food Technol., 36, 79-83. Watt, B. K. & Merrill, A. L. (1963). Composition of Foods. Agricultural Handbook no. 8, USDA, Washington DC, USA, p. 18.