Some Quality Characteristics of Commercial Liquid Rennet Samples


Abstract: The aim was to investigate some of the microbiological, physical, chemical and sensorial properties of commercial rennet samples collected from different regions in Turkey. A total of 25 liquid rennet samples were tested. The total aerobic mesophilic bacteria count was <1-2.5 x 10^6 cfu/ml, the yeast and/or mold count was <1-30 cfu/ml and the spore forming anaerobe count was <1-35 cfu/ml. None of the samples contained coliform bacteria. Sensorial analysis showed that 7 out of the 25 samples conformed to the Turkish Rennet Standard (TS-3844), which states that rennets are to be clear and caramel colored, carry no sediments and have a specific smell. The other 18 samples possessed none of the properties set out in the standard. pH values, salt levels and milk clotting activity of the samples ranged between 5.08 and 5.82, 4.83 and 14.05% and 1/5670 and 1/45450, respectively. Our results suggested that most of the commercial liquid rennet samples showed variations in terms of their microbiological, physical, chemical and sensorial properties and that the values were not within the limits of TS-3844.

Keywords: Chymosin, rennet, clotting, cheese

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