Preservation of Traditional Cheese Wagashi Using Essential Oils: Impact on Microbiological, Physico-chemical and Sensorial Characteristics

Aims: The high demand for food products without chemical additives has increased the use of natural preservatives like essential oils in food processing. The present study aimed to assess the impact of selected essential oils on the microbiological, physico-chemical and sensorial characteristics of preserved traditional cheese wagashi in order to improve its quality.

Materials and Methods: Microbiological and physico-chemical parameters were analysed repeatedly on days 0, 7, 30 and 60 using normalized methods in wagashi samples kept at 25°C and 4°C. Sensorial analyses were carried out once in 2 days old wagashi samples.

Results: Findings show that none of the analysed samples during the experimental period contains pathogenic microorganisms including Salmonella spp, Staphylococcus aureus, Escherichia coli and the spores of Clostridium spp. The pH of wagashi samples kept at 25°C decreased over time while their acidity, as well as the thiobarbituric acid index increased. The trend of these physico-chemical parameters was similar at 25°C as at 4°C; however the fluctuations were quite lower for the pH and the acidity at 4°C than at 25°C. For the sensorial quality of the initial products, the sample treated with the essential oil of Cymbopogon citratus was well appreciated by the tasters who mentioned that it was of good quality followed by the sample of wagashi treated with the essential oil of Pimenta racemosa qualified of fairly good. Samples treated with the essential oils of Ocimum gratissimum and Syzygium aromaticum were of acceptable quality.

Conclusion: This study revealed that the application of essential oils of Cymbopogon citratus and Pimenta racemosa in replacement of chemical additives constitutes a reliable alternative for the preservation of wagashi. However, a thorough study on the biochemical characterization of the samples is necessary to appreciate the quality of the elaborated products.