ABSTRACT
This study was conducted to investigate the general properties of an enzymatic extract of Sargassum muticum (SM) produced using a crude enzyme from Shewanella oneidensis PKA 1008 and their anti-inflammatory activities. The SM was mixed with crude enzymes from S. oneidensis PKA 1008 (1:1 (v/v)) and incubated at 30 °C for 0, 3, 6, 12, 24, 48, and 60 h. S. oneidensis PKA 1008 crude enzyme showed the highest SM enzymatic extracts degradation ability when reacted with SM for 48 h. These evaluations demonstrated a 134.25% increase in reducing sugar content and a 14.90% reduction in viscosity at 48 h. The pH, lightness (L*) and yellowness (b*) of the SM enzymatic extracts decreased significantly with increasing reaction time. Moreover, the SM enzymatic extracts demonstrated significant anti-inflammatory activity. These results indicate that the crude enzyme from S. oneidensis PKA 1008 can be used to enhance the polysaccharide degradation of SM, and the resultant oligosaccharides may have an anti-inflammatory effect.
ABSTRACT
In this study, gamma-irradiated mackerel (Scomber japonicus) meat was stored in a refrigerator for 20 days to examine the physicochemical changes related to fishy smell. The effect of gamma irradiation on the inhibition of the activity of crude urease extracted from Vibrio parahaemolyticus was also evaluated. Increased levels of trimethylamine (TMA) and volatile basic nitrogen (VBN) content, which are the main components causing fishy smell, were significantly reduced by day 20 of storage after gamma irradiation, indicating that freshness was maintained during storage. The ammonia nitrogen contents of 3, 7, 10, and 20 kGy gamma-irradiated groups were significantly decreased by 6.5, 15.2, 17.4, and 23.9%, respectively, compared to non-irradiated groups on day 20 of storage. In addition, urease activity decreased in a gamma irradiation intensity-dependent manner. Volatile organic compounds (VOCs) were measured during the storage of gamma-irradiated mackerel meat. The contents of ethanol, 2-butanone, 3-methylbutanal, and trans-2-pentenal, which are known to cause off-flavors due to spoilage of fish, were significantly reduced by day 20 of storage. Therefore, gamma irradiation can be considered useful for inhibiting urease activity and reducing fishy smell during fish storage.
Subject(s)
Perciformes , Smell , Animals , Fishes , Nitrogen , Seafood/analysis , UreaseABSTRACT
In this study, the physicochemical changes related to fishy smell were determined by storing high hydrostatic pressure (HHP)-treated mackerel (Scomber japonicus) meat in a refrigerator for 20 days. The inhibition of crude urease activity from Vibrio parahaemolyticus using HHP treatment was also investigated. The mackerel meat storage experiment demonstrated that production of trimethylamine (TMA) and volatile basic nitrogen (VBN), the main components of fishy smell, was significantly reduced on the 20th day of storage after the HHP treatment compared to the untreated mackerels. The results demonstrated that the increased ammonia nitrogen rates in the 2000, 3000, and 4000 bar, HHP-treated groups decreased by 23.8%, 23.8%, and 31.0%, respectively, compared to the untreated groups. The enzyme activity of crude urease was significantly reduced in the HHP-treated group compared to that in the untreated group. Measurement of the volatile organic compounds (VOCs) in mackerel meat during storage indicated that the content of ethanol, 2-butanone, 3-methylbutanal, and trans-2-pentenal, which are known to cause off-flavor due to spoilage, were significantly reduced by HHP treatment. Collectively, our results suggested that HHP treatment would be useful for inhibiting the activity of urease, thereby reducing the fishy smells from fish and shellfish.