Optimization the effect of Camellia sinensis (green tea) and و Hibiscus sabdariffa (sour tea) extracts on sensory, antibacterial and antioxidant properties in ice cream

Abstract

Incidence of food poisoning diseases regardless of industrial development is still a worrying issue that leads to researches for finding new methods of decreasing microbial loads. In the meantime dairy industry as one of the sensitive industries with high risk of contamination is a more serious concern. The interest to avoid using artificial preservatives and to use functional food has made this field an ongoing area that leads to cultivation of natural materials with these two benefits. Therefore in this study the effect of two natural extracts in ice cream was investigated in order to decrease the microbial load and increasing the functional food properties. Besides that, another important matter in scientific studies is to achieve economic methods to predict problems and find solutions without laboratory experiments. Scientific modeling which converts verifiable data to a general and accurate model helps to predict and optimize different processes. Aim: This study investigated statistical analysis, modeling and optimizing the effect of adding Camellia sinensis (green tea) extract and Hibiscus sabdariffa (sour tea) extract to ice cream. For this purpose, a model for antibacterial and anti-oxidant properties was prepared by monitoring Escherichia coli bacteria and Staphylococcus aureus in an ice cream containing Camellia sinensis (green tea) extract and Hibiscus sabdariffa (sour tea) extract. Sensory evaluation was also used for controlling public acceptance in order to achieve the final aim of this study which is to replace a special combination of herbal extracts in dairy products in order to modify microbial and anti-oxidant conditions. Materials and Methods: In order to evaluate the anti-microbial, anti-oxidant and sensory properties of Camellia sinensis (green tea) and Hibiscus sabdariffa (sour tea) extracts in ice cream first the alcohol extraction process took place. The ice cream, which was produced in an industrial unit due to consumer market’s standards was purchased and 13 different combinations of extracts were added to it according to design experiment method. These 13 samples with parent sample were observed and controlled for 4 months. Results: It was shown that besides the relation between Camellia sinensis (green tea) and Hibiscus sabdariffa (sour tea) extracts in ice cream and the rate of Escherichia coli bacteria and Staphylococcus aureus, a model for each test was presented and by that the best concentration of each extract was specified. Also with approval of anti-oxidant properties of Camellia sinensis (green tea) and Hibiscus sabdariffa (sour tea) extracts in a dairy bed, the optimize concentration of these extracts was shown after modeling, due to maximum anti-oxidant property. Sensory evaluation in 4 factors with hedonic method showed the high concentration of the extracts was not acceptable. Conclusion: This study specified the optimum combination of Camellia sinensis (green tea) and Hibiscus sabdariffa (sour tea) extracts which their anti-microbial properties were approved and with the final equation the possibility of fitting the presenting model to other similar conditions was obtained. The anti-oxidant properties of the extracts were more dependent on the Hibiscus sabdariffa (sour tea) concentration. Moreover according to sensory evaluators, the low acceptance was reported for semi-trained evaluators.