No abstract

The antimicrobial activity of lemon basil (Ocimum × africanum Lour.) has been described. This activity can be elaborated further and possibly applied for natural foods preservative. In this study, the constituents of lemon basil essential oil were analysed, and its preservation potential on the tofu was evaluated. The essential oil was distilled from dried plant materials using a steam and water distillation process. The constituents of essential oil of lemon basil were analysed by Gas Chromatography-Mass Spectroscopy (GC-MS) technique. Its application for preservation of tofu was evaluated based on its capacity in inhibiting the growth of bacteria on the tofu as well as the physical observation of the tofu during ten days of preservation at room temperature. The lemon basil essential oil constituted of 21 constituents, with a high fraction of oxygenated compounds, including neral and geranial, were detected. Lemon basil essential oil at an optimum concentration of 3.125 mg/ml inhibited the bacterial growth on the tofu during storage and improved its shelf life up to 4 days.

Syzygium polyanthum (Wight) Walp. (Indonesian bay leaf) is known for possessing antimicrobial activity that might be applied for natural food preservative. In this study, we analyzed the constituents of infusion of S. polyanthum leaves and evaluated its potency as the preservative of fresh chicken meats. The infusions were prepared with the method described in Indonesian Pharmacopeia. Phytochemical content of infusion of S. polyanthum leaves was analyzed by qualitative phytochemical screening using colorimetric methods. Its application for preservative of fresh chicken meat was evaluated based on its activity in inhibiting the growth of bacteria on the meats as well as the physical observation of the preserved meats. The infusion of S. polyanthum leaves contained flavonoids, tannins, and saponins. The infusion at the optimum concentration of 10% was capable of inhibiting bacterial growth on chicken meats and extending their shelf life up to 3 days in temperature of 3-7ºC.

Lemongrass (Cymbopogon citratus (DC.) Stapf, Poaceae) has been known for demonstrating antimicrobial activity against food spoilage bacteria. These antimicrobial properties can be further utilized for the development of natural food preservatives. In this study, the compounds present in water extract and essential oil of lemongrass were analyzed and their potential as tofu preservatives was evaluated. The water extract was prepared by the infusion method, while the essential oil was made by steam and water distillation. The phytochemicals composition of the water extract and essential oil was analyzed by qualitative colorimetric phytochemical screening and Gas Chromatography-Mass Spectroscopy (GC-MS) technique, respectively. Their preservative activity on tofu was evaluated by observing their ability to inhibit the growth of bacteria on the tofu and the physical changes of tofu during 10 days of preservation at room temperature. The results showed that lemongrass water extract contained terpenoids, tannins, and saponins. The GC-MS analysis identified 13 compounds in the essential oil. Neral, geranial, β-myrcene, juniper camphor, and viridiflorol were found as the major compounds. At concentration of 20%, lemongrass water extract demonstrated inhibition of bacterial growth during 10 day storage of tofu and improved the shelf life by 4 days longer from those of the negative control. In contrast, lemongrass essential oil did not show inhibitory activity in bacterial growth in tofu but it was capable of maintaining the color, odor, and texture of tofu as well as delaying the slime formation up to 4 days.

Lemon basil (Ocimum × africanum Lour.) is potentially developed into a natural food preservative as its antimicrobial activities have been proven against food-borne microorganisms. This study is designed to evaluate the preservation potential of lemon basil essential oil (EO) on chicken meat during 12 days of refrigerated storage. The steam-water distillation and Gas Chromatography-Mass Spectroscopy (GC-MS) techniques were used to extract and analyse chemical constituents of lemon basil EO, respectively. The microbial growth inhibitory activity was determined by the OD 600 nm-based indirect method, while the physical characters of the meat were organoleptically observed. A total yield of 0.20% lemon basil EO was obtained, which contained 38 compounds with neral, geranial, caryophyllene oxide, and α-bisabolene as main constituents. The optimum preservation effects were shown by lemon basil EO at a concentration of 625 ppm, which significantly decreased the microbial growth on the meat and delayed meats deterioration for six days. The preservation effects of lemon basil EO was likely related to the high fractions of aldehyde compounds in it.