Water soluble organic carbon （WSOC） in sediments plays an important role in transference and transformation of aquatic pollutants. This article investigated the inherent mechanisms of how sediemnt grain size affect ...Water soluble organic carbon （WSOC） in sediments plays an important role in transference and transformation of aquatic pollutants. This article investigated the inherent mechanisms of how sediemnt grain size affect the partitioning coeffcient （k） of WSOC. Influences of NaOH extracted humic substances were particularly focused on. Sediments were sampled from two cross-sections of the middle Yellow River and sieved into three size fractions （〈 63 μm, 63-100 μm, and 100-300 μm）. The total concentration of WSOC in sediments （Cwsoc） and k were estimated using multiple water-sediment ratio experiments. Results showed that Cwsoc ranged from 0.012 to 0.022 mg/g, while k ranged from 0.8 to 3.9 L/kg. Correlations between the spectrum characteristics of NaOH extracted humic substances and k were analyzed. Strong positive correlations are determined between k and the aromaticity indicators of NaOH extracted humic substances in different sediment size fractions. Comparing with finer fractions （〈 63 μm）, k is higher in larger size fractions （63- 100 μm and 100-300 μm） related to higher aromaticity degree of NaOH extracted humic substances mostly. While negative relationship between k and the area ratio of fourier transform infrared spectroscopy （FT-IR） at 3400 and 1430 cm^-1 implied that the lowest k was related to the highest concentration of acidic humic groups in particles 〈 63 μm. WSOC in finer fractions （〈 63 μm） is likely to enter into pore water, which may further accelerate the transportation of aquatic contaminants from sediment to water.展开更多
为了研究克氏原螯虾水溶性滋味物质游离氨基酸的含量、组成及其呈味效果,分别对野生和养殖克氏原螯虾的虾肉和虾头中的游离氨基酸进行测定。结果显示:对克氏原螯虾虾肉呈味贡献最大的是精氨酸(Arg),其含量占游离氨基酸总量的43.7%~48.6%...为了研究克氏原螯虾水溶性滋味物质游离氨基酸的含量、组成及其呈味效果,分别对野生和养殖克氏原螯虾的虾肉和虾头中的游离氨基酸进行测定。结果显示:对克氏原螯虾虾肉呈味贡献最大的是精氨酸(Arg),其含量占游离氨基酸总量的43.7%~48.6%,味道强度值(taste active value,TAV)为4.18~6.77,远高于其他游离氨基酸,提高鲜度的同时增加了呈味复杂性,其次是丙氨酸(Ala)和组氨酸(His),其TAV值分别在1~2之间;对克氏原螯虾虾头呈味贡献最大的是赖氨酸(Lys)、Arg和谷氨酸(Glu),其TAV值均在1.68~2.61之间。野生与养殖克氏原螯虾虾肉和虾头中主要游离氨基酸(free amino acid,FAA)的组成成分、含量和对呈味的贡献存在显著差异。展开更多
基金supported by the Major State Basic Research Program of China (No. 2007CB407202)the National Natural Science Foundation of China (No. 40501063).
文摘Water soluble organic carbon （WSOC） in sediments plays an important role in transference and transformation of aquatic pollutants. This article investigated the inherent mechanisms of how sediemnt grain size affect the partitioning coeffcient （k） of WSOC. Influences of NaOH extracted humic substances were particularly focused on. Sediments were sampled from two cross-sections of the middle Yellow River and sieved into three size fractions （〈 63 μm, 63-100 μm, and 100-300 μm）. The total concentration of WSOC in sediments （Cwsoc） and k were estimated using multiple water-sediment ratio experiments. Results showed that Cwsoc ranged from 0.012 to 0.022 mg/g, while k ranged from 0.8 to 3.9 L/kg. Correlations between the spectrum characteristics of NaOH extracted humic substances and k were analyzed. Strong positive correlations are determined between k and the aromaticity indicators of NaOH extracted humic substances in different sediment size fractions. Comparing with finer fractions （〈 63 μm）, k is higher in larger size fractions （63- 100 μm and 100-300 μm） related to higher aromaticity degree of NaOH extracted humic substances mostly. While negative relationship between k and the area ratio of fourier transform infrared spectroscopy （FT-IR） at 3400 and 1430 cm^-1 implied that the lowest k was related to the highest concentration of acidic humic groups in particles 〈 63 μm. WSOC in finer fractions （〈 63 μm） is likely to enter into pore water, which may further accelerate the transportation of aquatic contaminants from sediment to water.
文摘为了研究克氏原螯虾水溶性滋味物质游离氨基酸的含量、组成及其呈味效果,分别对野生和养殖克氏原螯虾的虾肉和虾头中的游离氨基酸进行测定。结果显示:对克氏原螯虾虾肉呈味贡献最大的是精氨酸(Arg),其含量占游离氨基酸总量的43.7%~48.6%,味道强度值(taste active value,TAV)为4.18~6.77,远高于其他游离氨基酸,提高鲜度的同时增加了呈味复杂性,其次是丙氨酸(Ala)和组氨酸(His),其TAV值分别在1~2之间;对克氏原螯虾虾头呈味贡献最大的是赖氨酸(Lys)、Arg和谷氨酸(Glu),其TAV值均在1.68~2.61之间。野生与养殖克氏原螯虾虾肉和虾头中主要游离氨基酸(free amino acid,FAA)的组成成分、含量和对呈味的贡献存在显著差异。
