THE NUTRITIONAL VALUE OF KISHK: DRIED WHEAT FERMENTED MILK EGYPTIAN NATIVE DAIRY FOOD
Kishk is dried wheat fermented milk mixture originated during Pharonic period since 3200 yr, B.C. in Upper Egypt and continued until nowadays. It is considered a good source of carbohydrates, proteins, vitamins and minerals. Egyptian farmers prepared kishk as a home made product mainly for their consumption. However, considerable amounts of the product may be marketed to gain additional profit.
Objectives: The aim of this proposal was to evaluate the nutrition value of kishk. Therefore, Gross composition and minerals content were determined. Quality and quantity of fatty acids as parameters of functionality were also analyzed.
Materials and Methods: Forty kishk samples were procured from four provinces encoded as A, B, F, and G located in Upper Egypt (10 samples from each). Gross composition and minerals were examined according to (APHA, 2004). Moreover, quality and quantity of FAs methyl ester were pursued using Agilent Technologies 6890 N GC/MS equipped with a flame ionization detector (FID) and a HP-5% Phenyl Methyl Silixane capillary column. Helium was used as a carrier gas. The oven temperature was 70oC with a 2 min.hold. Injector and detector temperatures were250o and 280oC respectively. FAMEs were identified by comparison its retention times with that of standard FAMEs mixture (Sigma, USA).
Results: Mean gross compositions were: moisture, 6.82, 7.24, 7.02 & 7.23; total solids, 93.18, 92.69, 92.98 & 92.77; and total carbohydrates, 65.43, 69.83, 73.09 & 69.43 g/ 100g sample for A, B, F, and G kishk respectively. Mean protein and fat contents were, 18.84, 11.60, 11.87 , 11.43; and, 4.85, 3.21, 3.51 & 3.43 g/100g dry matter in the same order respectively. Po, K, Ca, Mg, Na, Fe, Mn, Zn and Cu were determined in varying concentrations. FA profile includes saturated, monounsaturated and polyunsaturated fatty acids from C10 to C21. Octadecadieonic and octadecatrienoic acids were detected in all kishk samples examined. However, Kishk A was distinguished contains conjugated linoleic acid 10t,12cCLA. Perhaps this was the first report to document presence of beneficial CLA isomer in kishk. .
Conclusion: Kishk is a very nutritive functional food containing carbohydrates, protein, fat and minerals. Moreover, occurrence of essential PUFA and CLA ensure its functionality for human health.
Keywords: Kishk, CLA, functional food