46H-4 |
Antibacterial effect and antioxidant content of Tom-yam |
S. SIRIPONGVUTIKORN1, Y. W. Huang1, and P. Thummaratwasik2. (1) Dept. of Food Science & Technology, Univ. of Georgia, 204 Food Science Bldg., Athens, GA 30602-7610, (2) Faculty of Agro-Industry, Prince of Songkla Univ., Hat-yai, 90110, Thailand In the last few years, Tom-yam soup, a Thai food, has become a very popular spicy food item worldwide. This is due to the taste and its health effect. Japanese researchers recently discovered that some components found in galangal root, lemon grass, and kaffir leave – three main ingredients of the soup are effective in inhibiting tumors in the digestive tract. However, no scientific research using whole Tom-yam as a functional food or as a natural preservative is available. The objectives were to determine the antibacterial effect and antioxidant content of the Tom-yam mix. Two Gram-negative bacteria (Pseudomonas fluorescens ATCC 49839, and Escherichia coliO157H:7 204P) and two Gram-positive bacteria (Staphylococcus aureus ATCC 13565 and Listeria monocytogenes) were used to determine the antibacterial activity of individual spices and their mix. Samples were ground to break the plant cell and the disc diffusion method was used to determine the antibacterial activity. The antioxidants beta-carotene and isoflavone in Tom-yam and the other ingredients were determined by using a HPLC method. Among the ingredients used in Tom-yam, garlic exhibited the highest inhibition (the clear zone was about 2.0-2.5 cm), while shallot, lemon grass and galangal root were ineffective. Tom-yam mix also exhibited a high antibacterial activity (the clear zone was about 1.5 cm) and kaffir leave was less effective on S. aureus. For the antioxidant level, red chili has the highest content of beta-carotene (0.39-0.43 mg/g sample), and garlic has the highest content of daidzein (2.05-2.50 mg/g sample). Daidzein was present in all the spices but no flavone was detected. Tom-yam mix has a great potential as a functional food as well as a natural antibacterial agent that may be used to ensure a safe food product by, e.g., marination of muscle foods.
Session 46H, Religious & Ethnic Foods
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