Microcystis bloom, one of the most objectionable characteristics of eutrophication in tropical and subtropical waters, occurred in Donghu Lake (East Lake) of Wuhan every summer from the 1970s up to 1984, but from 1985...Microcystis bloom, one of the most objectionable characteristics of eutrophication in tropical and subtropical waters, occurred in Donghu Lake (East Lake) of Wuhan every summer from the 1970s up to 1984, but from 1985 up to now failed to occur there. The cause of its disappearance remained in obscurity until recently. In situ enclosure experiments in the lake for three years showed that the stocking of the filter-feeding silver carp (Hypophthalmichthys molitrix) and big-head carp (Aristichthys nobilis) played a decisive role in eliminating Microcystis bloom from the lake; but that recurrence of the bloom is possible under certain conditions. This paper presents the details and the results of enclosure experiments. The authors’ analysis of fish biomass data obtained by echo-sounding and the fishery production of the lake over the years, revealed that the recurrence of Microcystis bloom can be prevented so long as the combined biomass of silver carp and big-head carp remains at or exceeds 50 g per cubic meter of lakewater, as was the case in the lake’s 1985 fish yield of 1015 t.展开更多
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 sauc...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.展开更多
文摘Microcystis bloom, one of the most objectionable characteristics of eutrophication in tropical and subtropical waters, occurred in Donghu Lake (East Lake) of Wuhan every summer from the 1970s up to 1984, but from 1985 up to now failed to occur there. The cause of its disappearance remained in obscurity until recently. In situ enclosure experiments in the lake for three years showed that the stocking of the filter-feeding silver carp (Hypophthalmichthys molitrix) and big-head carp (Aristichthys nobilis) played a decisive role in eliminating Microcystis bloom from the lake; but that recurrence of the bloom is possible under certain conditions. This paper presents the details and the results of enclosure experiments. The authors’ analysis of fish biomass data obtained by echo-sounding and the fishery production of the lake over the years, revealed that the recurrence of Microcystis bloom can be prevented so long as the combined biomass of silver carp and big-head carp remains at or exceeds 50 g per cubic meter of lakewater, as was the case in the lake’s 1985 fish yield of 1015 t.
文摘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.
