The study investigated the survival ability of probiotic Lactobacillus
casei in apple juice to produce functional juice ,as well as,
optimizing the growth conditions of L.casei in apple juice including
concentration, temperature ,inoculum size usi
ng Response Surface
Methodology as statistical method.
Some quality indicators were studied , such as lactic acid bacteria and
probiotic count during and after the preservation period .
This study was conducted in order to prolong the period of validity of
yoghurt by adding probiotics consisted of Lactobacillus acidophilus LA-5 and
Bifidobacterium animalis subsp lactis (Bb12) to milk allocated to yoghurt
industry and studied the
microbial, chemical and sensory characteristics of
yoghurt during storage periods for 0, 7،,14, 21, 28, 35 and 42 days at 4 ± 1 °C
and 10 ± 1 °C. The results of microbial characteristics showed that the vital
force of the first starter lasted for 7 days in the control samples while lasted for
35 days for the sample containing Lactobacillus acidophilus LA-5 or
Bifidobacterium animalis subsp lactis (Bb12) when stored at 4 ± 1°C. Adding
probiotics did not affect the taste, smell and pH of the yoghurt without change
in the property values during storage periods. It was also found that the shelf –
life of control samples can be prolonged and consumed safely up to 7 days of
storage while it was prolonged for 35 days in yoghurt samples containing
probiotics.
