MUTAGENICITY AND CARCINOGENICITY OF FISH SAUCE FROM A COUNTY WITH THE HIGH RISK FOR GASTRIC CANCER IN CHINA

The mutagenicity and carcinogenicity of fish sauce (FS) sample from Changle County, a high gastric cancer mortality (113.20/105) area, were investigated with the biologic short-term tests and laboratory animal experiment. The results showed that the extract of FS was markedly direct mutagenic toward S. typhimurium TA100, induced high sister chromatid exchanges (SCE) and micronucleus (MN) in V79 cells after nitrosation with sodium nitrite. But the non-nitrosated FS did not. The nitrosated fish sauce (NFS) also induced SOS in E. coli PQ37 and alkylation of calfthymus DNA. The potency of NFS to induce unscheduled DNA synthesis (UDS) in human normal gastric mucosal cells was increased about fivefold compared with FS. When the NFS extract was given to newborn rats by gavage, dys-plasia and adenocaroinoma were induced in the glandular stomach in the 4th and 16th experimental week, respectively. N-nitrosamides were also found in NFS, which may account for the mutagenicity and carcinogenicity of NFS. It is indicated that FS, a traditional daily eaten seasoning, may contribute to the causes of the high gastric cancer mortality for the local residents.

Confirmation of N-(Nitrosomethyl) urea as a Nitrosourea Derived by Nitrosation of Fish Sauce

N-(nitrosomethyl ) urea (NMU ) was characterized in the carcinogenic nitrosated fish sauce (NFS) with high performance liquid chromatography (HPLC )- pholohydrolysis-pyrolysis-thermal en -ergy analysis recently. We used HPLC-electronic spray ionization-mass spectrometry and HPLC-diode array detection to confirm NMU in NFS furiher. It was observed that the corresponding chro-matographic fraction of NMU of NFS showed the same mass spectrum (m/z 64, 102, and 145) andultraviolet-absorbance (λ max = 230 nm) as those of authentic NMU. These results confirmed that thecomponent of NFS was NMU

Analysis of volatile components in a Chinese fish sauce,Fuzhou Yulu, by gas chromatography-mass spectrometry

Volatile components of Fuzhou Yulu, a Chinese fish sauce, were analyzed by gas chromatography-mass spectrometry （GC-MS）, and two pretreatment methods, i.e., purge and trap （P＆T） GC-MS and ethyl acetate extraction followed by GC-MS, were compared. P＆T-GC-MS method determined 12 components, including sulfur-containing constituents （such as dimethyl disulfide）, nitrogen-containing constituents （such as pyrazine derivatives）, aldehydes and ketones. Ethyl acetate extraction fol- lowed by GC-MS method detected 10 components, which were mainly volatile organic acids （such as benzenepropanoic acid） and esters. Neither of the two methods detected alcohols or trimethylamine. This study offers an important reference to determine volatile flavor components of traditional fish sauce through modem analysis methods.

Fish Sauce Fermentation with Silver Carp or Offal of Surimi Processing

Fish sauce is a kind of condiments processed from fish. The L9（34） orthogonal tests have been carried out to inspect the effects of technological conditions for fermentation on the comprehensive quality of fish sauce. The conditions of the orthogonal tests are following: the fermentation temperature takes values of 35℃, 40℃ and 45℃, the percentage of Koji values of 40%, 20% and 10% and the percentage of salt values of 10%, 14% and 18%. The obtained experimental results indicate that fermentation temperature plays an important role in the improvement of sauce quality. The optimal technological conditions for sauce fermentation are of 10% salt, 45℃ and 40% koji mixed. The composition of fish sauce processed from offal of silver carp-surimi processing under the above-mentioned conditions and two commercial products have been analyzed. The results show that fish sauce processed from fish offal is nutritious and delicious. It is suggested that the fermentation of fish sauce is a potential and promising pathway to make full use of freshwater fish resources and offal in fish processing. In this study, fuzzy theory and analytic hierarchy process have been applied and the quality evaluation has been established by the combination of physico-chemical indices and sensory evaluation. The comprehensive evaluation has been taken to reflect the optimal factors for the process of sauce fermentation. The quality indexes for fish sauce contain sensory evaluation, amino nitrogen, total nitrogen, specific gravity, volatile basic nitrogen, salt concentration, brown index and acidity, represented by y1, y2, y3, y4, y5, y6, y7, y8, and y9, respectively. They form a group U= {y1, y2, y3, y4, y5, y6, y7, y8, y9,}. Using the fuzzy functions, the values of all these factors are transformed into fuzzy degrees of single factor, i.e. numerical values between 0 and 1. The fuzzy degrees of single factor in several samples are made up a matrix R. Following that, a weight of each index can be determined in the comprehensive evaluation. In the analytic hierarchy process, the weight can be obtained by the cross comparison between two different factors. The results show that the weights （W） of sensory evaluation, amino nitrogen, total nitrogen, specific gravity, volatile basic nitrogen, salt concentration, brown index and acidity are 0.356, 0.189, 0.107, 0.054, 0.097, 0.063, 0.061 and 0.073 respectively. Finally the aggregated fuzzy degree （B） of different samples is computed by B=W·R, which can be taken as the final result of comprehensive evaluation. The larger this value is, the higher the quality of sauce product would be.

Influences of salt and koji contents on chemical properties of fish sauce from tilapia frames

Influences of salt(5%-20%w/w of digested material)and soybean koji(3%-10%w/w of digested material)on chemical properties of fish sauce from tilapia frame after 4 months’fermentation using response surface methodology was studied.Results found that the salt content showed quadratic effect on ammonia nitrogen and amino nitrogen while linear effect on formaldehyde nitrogen and NaCl contents of samples were observed(P<0.05).Estimation response surfaces revealed that the formaldehyde nitrogen,ammonia nitrogen and amino nitrogen contents decreased while NaCl content increased as salt content increased.For the effect of koji,the significant effect of koji content on non-enzymatic browning value of fish sauce samples in linear manner was observed(P<0.05).The non-enzymatic browning value of sample increased as koji content increased.The both of salt and koji contents showed the linear effect on total acidity value while two-factor interaction terms on total nitrogen of sample was found(P<0.05).For the consumer acceptability testing,an acceptance score of the incubated fish sauce sample with a values of 6.50-7.43(like slightly to like moderately)was obtained.The results showed that it is possible to make a good quality fish sauce from tilapia frame by-product.