Antioxidant activity of the giant jellyfish Nemopilema nomurai measured by the oxygen radical absorbance capacity and hydroxyl radical averting capacity methods.

The giant jellyfish Nemopilema nomurai (reaching sizes of up to 2 m diameter and 150 kg), which forms dense blooms, has caused extensive damage to fisheries by overloading trawl nets, while its toxic nematocysts cause dermatological symptoms. Giant jellyfish are currently discarded on the grounds of pest control. However, the giant jellyfish is considered to be edible and is part of Chinese cuisine. Therefore, we investigated whether any benefits for human health may be derived from consumption of the jellyfish in order to formulate medicated diets. Antioxidant activity of Nemopilema nomurai was measured using the oxygen radical absorbance capacity (ORAC) and hydroxyl radical averting capacity (HORAC) methods. Based on the results, the ORAC value of the giant jellyfish freeze-dried sample was 541 µmol trolox equivalent (TE)/100 g and the HORAC value was 3,687 µmol gallic acid equivalent (GAE)/100 g. On the other hand, the IC50 value of hydroxyl radical scavenging activity measured by using the electron spin resonance method was 3.3%. In conclusion, the results suggest that the freeze-dried powder of the giant jellyfish Nemopilema nomurai is a potentially beneficial food for humans.

Radical scavenging activity of 'Nikogori' gelatin gel food made from head, bone, skin, tail and scales of fishes measured using the chemiluminescence method.

Head, bone, skin and tail mixed parts of yellowtail and bream, scales of bream and head of salmon which have nutritional values and are usually discarded were made into 'Nikogori' gelatin gel. They are not only a good source of protein but are also useful for elderly people with swallowing problems. Soy sauce, a traditional seasoning in Japan, was added to enhance the taste of 'Nikogori'. The rheological properties were examined by a rheometer and the peroxyl radical scavenging activity was measured by the chemiluminescence method. Sensory evaluation was also conducted employing 20 faculty members and students of the Laboratory of Cookery Science, Tokyo Kasei University, Japan to assess its acceptance. It was found that 'Nikogori' has peroxyl radical scavenging activity. Moreover, addition of soy sauce to 'Nikogori' enhanced the peroxyl radical scavenging activity. The rheological properties of 'Nikogori' and of the soy sauce added conformed to the standard set by the Ministry of Health, Labour and Welfare of Japan for elderly people with swallowing problems. From the data of the antioxidative activity and the sensory evaluation, the soy sauce-added 'Nikogori' was preferrable to that of the non-added one.

Measurement of the radical scavenging activity of chicken jelly soup, a part of the medicated diet, 'Yakuzen', made from gelatin gel food 'Nikogori', using chemiluminescence and electron spin resonance methods.

We reported that gelatin gel 'Nikogori' soup made from the collagen in chicken wing meat, which is a part of the medicated diet 'Yakuzen', has high peroxyl and hydroxyl radical scavenging activities as the antioxidative capacity using chemiluminescence and electron spin resonance methods. The peroxyl radical scavenging activity of the soy sauce and chicken jelly 'Nikogori' soup sample was much higher than that of the chicken-only sample (control) at 100 degrees C heating for 60 min, although the addition of soy sauce only slightly enhanced the hydroxyl radical scavenging activity. Although the addition of garlic slightly enhanced the hydroxyl radical scavenging activity, it strongly inhibited the peroxyl radical scavenging activity. We found that chicken jelly 'Nikogori' soup only and soup with the addition of soy sauce had the highest antioxidative capacity as part of the medicated diet, 'Yakuzen'.

Effect of soy sauce on the antioxidative capacity of the gelatin gel food 'Nikogori' measured using the chemiluminescence method.

Oxygen-related free radicals have been suggested as a cause of aging and various diseases, for example, various cancers and rheumatoid arthritis. Because of this a radical scavenger as an antioxidant has been sought in many foods. 'Nikogori' gelatin gel from cooked fish is a traditional food in Japan. Recently, 'Nikogori' has been noted as a readily consumed food for the elderly and those with medical problems associated with swallowing. In this study we report that the 'Nikogori' gelatin gels made from the collagen in various meats have a high peroxyl radical scavenging capability as the antioxidative capacity using the chemiluminescence method and the order of the strength of antioxidative capacity (IC(50) value) was the Japanese common squid mantle meat (0.163%) > flatfish (marbled sole) meat (0.534%) > chicken wing meat (0.585%) > beef shin meat (0.655%) > yellowtail meat (0.659%) > chub mackerel meat (0.789%). Furthermore, when soy sauce was added to the 'Nikogori' gelatin gel, the antioxidative capacity increased markedly to 0.098% of IC(50) value of yellowtail, 0.165% of chicken, 0.182% of flatfish and 0.252% of chub mackerel.