Food & Nutrition

Arab Journal of Food & Nutrition
33. Improvement of the Quality of “Halawa Tahinia” with Special Emphasis on
the Problem of Oil Separation (1998)
Taha Mohammed Al- Ahmed Rababa’h\ University of Jordan
Supervisor: Dr. Mohammed A. Humeid
The aim of this study was to look for a practical solution for the problem of oil
separation in halawa tahinia (halawa).
Microscopic examination of halawa indicated that it is composed of porous
noncrystalline sugar melt particles surrounded by a precipitated protein layer
originating form tahina. The oil is found as a (non-emulsified) fluid, filling the spaces
between solid particles. Thus, oil separation was explained as a result of the
compression of the halawa matrix under the effect of gravity.
A simple but exact gravimetric method was developed to measure the oil
separation. The comparison between the texture of traditional halawa and a modified
one prepared by mixing cooked sugar (without the addition of saponaria extract) with
tahina revealed that the presence of saponin in molten sugar particles and on their
surface is responsible for the precipitation of the colloidal proteins of tahina, and for
obtaining a soft (fragile) texture of halawa, since the modified halawa showed a pasty
texture. On the other hand, it was found that the amount of saponaria extract added
according to the traditional procedure (which represents 168-238mg saponin for each
kg halawa) is most suitable regarding the overall quality of halawa, since the use of a
lesser amount increased oil separation whereas higher amounts resulted in a product
with a too fragile structure. It was also obvious that the parameter used in the
traditional processing method regarding the cooking temperature of sugar and mixing
time is adequate to obtain the desired texture of halawa.
The addition of 1% or 2.5% of un-hydrogenated palm oil (which is solid at room
temperature) was found to prevent oil separation from halawa when halawa was stored
at room temperature (25°C), while this addition, as well as other additives, failed to
prevent the separation when halawa was stored at 40°C.
The mechanism of preventing oil separation seems to be related to the increase of
viscosity of the oil phase due to the addition of the solid palm oil, since the
measurement of the viscosity of two mixtures of palm oil in sesame oil (at 1 and 15%
level) showed a high increase of viscosity at 25°C and no increase at 40°C.
The other tested additives, including glycerol, proteins, emulsifiers, Arabic gum,
carboxy methyl cellulose (CMC), calcium chloride and others, failed to prevent oil
separation, though some of them resulted in statistically significant reductions of oil
separation which were of no practical value. The results of preparing halawa from
tahina and ground sugar or cooked sugar, but without the addition of saponaria extract,
indicated the possibility of producing a spreadable halawa type.
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Volume 46 11, No. 25, 2011