Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase microextraction gas chromatography mass spectrometry(HS-SPME-GC-MS) analysis of volatiles from untreate...Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase microextraction gas chromatography mass spectrometry(HS-SPME-GC-MS) analysis of volatiles from untreated samples and three deodorized samples(under the optimal conditions) of Paphia undulata enzymatic hydrolysate revealed that the compounds contributing to the distinctive odor were 1-octen-3-ol, n-hexanal, n-heptanal, 2,4-heptadienal, and 2,4-decadienal, whereas n-pentanal, n-octanal, n-octanol, benzaldehyde, 2-ethylfuran and 2-pentylfuran were the main contributors to the aromatic flavor. The deodorizing effects of activated carbon(AC) adsorption, yeast extract(YE) masking and tea polyphenol(TP) treatment on a P. undulata enzymatic hydrolysate were investigated using orthogonal experiments with sensory evaluation as the index. The following optimized deodorization conditions were obtained: AC adsorption(35 mg mL^(-1), 80℃, 40 min), YE masking(7 mg mL^(-1), 45℃, 30 min) and TP treatment(0.4 mg mL^(-1), 40℃, 50 min). AC adsorption effectively removed off-flavor volatile aldehydes and ketones. YE masking modified the odor profile by increasing the relative contents of aromatic compounds and decreasing the relative contents of aldehydes and ketones. The TP treatment was not effective in reducing the odor score, but it significantly reduced the relative content of aldehydes while increasing that of alkanes. It is also notable that TP effectively suppressed trimethylamine(TMA) formation in a P. undulate hydrolysate solution for a period of 72 h.展开更多
In the present study, ultrasonic extraction technique(UET) is used to improve the yield of polysaccharides from Laminaria japonica(LJPs). And their antioxidative as well as glycosidase inhibitory activities are invest...In the present study, ultrasonic extraction technique(UET) is used to improve the yield of polysaccharides from Laminaria japonica(LJPs). And their antioxidative as well as glycosidase inhibitory activities are investigated. Box-Behnken design(BBD) combined with response surface methodology(RSM) is applied to optimize ultrasonic extraction for polysaccharides. The optimized conditions are obtained as extraction time at 54 min, ultrasonic power at 1050 W, extraction temperature at 80℃ and ratio of material to solvent at 1:50(g m L-1). Under these optimal ultrasonic extraction conditions, an actual experimental yield(5.75% ± 0.3%) is close to the predicted result(5.67%) with no significant difference(P > 0.05). Vitro antioxidative and glycosidase inhibitory activities tests indicate that the crude polysaccharides(LJP) and two major ethanol precipitated fractions(LJP1 and LJP2) are in a concentration-dependent manner. LJP2(30%-60% ethanol precipitated polysaccharides) possesses the strongest α-glucosidase inhibitory activity and moderate scavenging activity against hydroxyl radicals(66.09% ± 2.19%, 3.0 mg m L-1). Also, the inhibitory activity against α-glucosidase(59.08% ± 3.79%, 5.0 mg m L-1) is close to that of acarbose(63.99% ± 3.27%, 5.0 mg m L-1). LJP1(30% ethanol precipitated polysaccharides) exhibits the strongest scavenging activity against hydroxyl radicals(99.80% ± 0.00%, 3.0 mgm L-1) and moderate α-glucosidase inhibitory activity(47.76% ± 1.92%, 5.0 mg m L-1). LJP shows the most remarkable DPPH scavenging activity(66.20% ± 0.11%, 5.0 mg m L-1) but weakest α-glucosidase inhibitory activity(37.77% ± 1.30%, 5.0 mg m L-1). However, all these LJPs exert weak inhibitory effects against α-amylase. These results show that UET is an effective method for extracting bioactive polysaccharides from seaweed materials. LJP1 and LJP2 can be developed as a potential ingredient in hypoglycemic agents or functional food for the management of diabetes. This study provides scientific evidence and advances in the preparation technology and a hypoglycemic activities evaluation method for seaweed polysaccharides, especially glycosidase inhibition in combination with an antioxidative activity evaluation method.展开更多
The present study investigated the removal of inorganic arsenic from Pinctada martensii enzymatic hydrolysate through unmodified resin(D296) and Zr(Ⅳ)-loaded chelating resin(Zr-D401).By loading Zr to macroporous chel...The present study investigated the removal of inorganic arsenic from Pinctada martensii enzymatic hydrolysate through unmodified resin(D296) and Zr(Ⅳ)-loaded chelating resin(Zr-D401).By loading Zr to macroporous chelating resin D401,the as exchange adsorption active sites are generated.This transforms D401 from a material that does not have the arsenic adsorption capacity into a material that has excellent arsenic exchange adsorption capacity.The static adsorption experiments were conducted to investigate the optimal removal condition for D296 and Zr-D401.The experimental results show that: the optimum condition for D296 is that T= 25℃,pH = 5,resin additive amount = 1 g(50 mL)-1,and contact time = 10 h,the corresponding arsenic removal rate being 65.7%,and protein loss being 2.33%;the optimum condition for Zr-D401 is that T=25℃,pH = 8,resin additive amount = 1 g(50 mL)-1,and contact time=10 h,the corresponding arsenic removal rate being 70.3%,and protein loss being 4.65%.These results show that both of the two resins are effective in arsenic removal for preserving useful substance.Our research provides scientific evidence and advances in the processing technology for heavy metal removal in shellfish.展开更多
基金supported by the Public Science and Technology Research Funds Projects of Ocean (No.201305018)the National Key Technology Research and Development Program for the 12th Five-Year Plan (No.2012BAD33B10)+3 种基金the National Natural Science Foundation of Guangdong, China (Nos. 2014A 030310351 and 2014A030310338)the Innovative Development of Marine Economy Regional Demonstration Projects of Guangdong (Nos.SZHY2012-B01-004 and GD2013-B03-001)the Science and Technology Planning Project of Guangdong Province, China (Nos.2013B 090800002 and 2015B090904003)the National Science Foundation for Young Scientists of China (No.31101271)
文摘Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase microextraction gas chromatography mass spectrometry(HS-SPME-GC-MS) analysis of volatiles from untreated samples and three deodorized samples(under the optimal conditions) of Paphia undulata enzymatic hydrolysate revealed that the compounds contributing to the distinctive odor were 1-octen-3-ol, n-hexanal, n-heptanal, 2,4-heptadienal, and 2,4-decadienal, whereas n-pentanal, n-octanal, n-octanol, benzaldehyde, 2-ethylfuran and 2-pentylfuran were the main contributors to the aromatic flavor. The deodorizing effects of activated carbon(AC) adsorption, yeast extract(YE) masking and tea polyphenol(TP) treatment on a P. undulata enzymatic hydrolysate were investigated using orthogonal experiments with sensory evaluation as the index. The following optimized deodorization conditions were obtained: AC adsorption(35 mg mL^(-1), 80℃, 40 min), YE masking(7 mg mL^(-1), 45℃, 30 min) and TP treatment(0.4 mg mL^(-1), 40℃, 50 min). AC adsorption effectively removed off-flavor volatile aldehydes and ketones. YE masking modified the odor profile by increasing the relative contents of aromatic compounds and decreasing the relative contents of aldehydes and ketones. The TP treatment was not effective in reducing the odor score, but it significantly reduced the relative content of aldehydes while increasing that of alkanes. It is also notable that TP effectively suppressed trimethylamine(TMA) formation in a P. undulate hydrolysate solution for a period of 72 h.
基金supported by the Project of National Key Technology Research and Development Program for the 12th Five-year Plan(No.2012BAD33B10)Public Science and Technology Research Funds Projects of Ocean(No.201305018-2)+4 种基金the Innovative Development of Marine Economy Regional Demonstration Projects(Nos.SZHY2012-B01-004,GD2013-B03-001)the National Scien-ce Foundation for Young Scientists of China(No.31101271)the Natural Science Foundation of Guangdong Province(Nos.2014A030310338,2014A030310351)the Comprehensive Strategic Cooperation Programs between the Guangdong Province and Chinese Academy of Sciences(No.2011B090300057)the Frontier Science Program for Young Scientists of South China Sea Institute of Oceanology,Chinese Academy of Science(No.SQ 201017)
文摘In the present study, ultrasonic extraction technique(UET) is used to improve the yield of polysaccharides from Laminaria japonica(LJPs). And their antioxidative as well as glycosidase inhibitory activities are investigated. Box-Behnken design(BBD) combined with response surface methodology(RSM) is applied to optimize ultrasonic extraction for polysaccharides. The optimized conditions are obtained as extraction time at 54 min, ultrasonic power at 1050 W, extraction temperature at 80℃ and ratio of material to solvent at 1:50(g m L-1). Under these optimal ultrasonic extraction conditions, an actual experimental yield(5.75% ± 0.3%) is close to the predicted result(5.67%) with no significant difference(P > 0.05). Vitro antioxidative and glycosidase inhibitory activities tests indicate that the crude polysaccharides(LJP) and two major ethanol precipitated fractions(LJP1 and LJP2) are in a concentration-dependent manner. LJP2(30%-60% ethanol precipitated polysaccharides) possesses the strongest α-glucosidase inhibitory activity and moderate scavenging activity against hydroxyl radicals(66.09% ± 2.19%, 3.0 mg m L-1). Also, the inhibitory activity against α-glucosidase(59.08% ± 3.79%, 5.0 mg m L-1) is close to that of acarbose(63.99% ± 3.27%, 5.0 mg m L-1). LJP1(30% ethanol precipitated polysaccharides) exhibits the strongest scavenging activity against hydroxyl radicals(99.80% ± 0.00%, 3.0 mgm L-1) and moderate α-glucosidase inhibitory activity(47.76% ± 1.92%, 5.0 mg m L-1). LJP shows the most remarkable DPPH scavenging activity(66.20% ± 0.11%, 5.0 mg m L-1) but weakest α-glucosidase inhibitory activity(37.77% ± 1.30%, 5.0 mg m L-1). However, all these LJPs exert weak inhibitory effects against α-amylase. These results show that UET is an effective method for extracting bioactive polysaccharides from seaweed materials. LJP1 and LJP2 can be developed as a potential ingredient in hypoglycemic agents or functional food for the management of diabetes. This study provides scientific evidence and advances in the preparation technology and a hypoglycemic activities evaluation method for seaweed polysaccharides, especially glycosidase inhibition in combination with an antioxidative activity evaluation method.
基金supported by National Key Technologies R&D Program of China(2008 BAD94B08)
文摘The present study investigated the removal of inorganic arsenic from Pinctada martensii enzymatic hydrolysate through unmodified resin(D296) and Zr(Ⅳ)-loaded chelating resin(Zr-D401).By loading Zr to macroporous chelating resin D401,the as exchange adsorption active sites are generated.This transforms D401 from a material that does not have the arsenic adsorption capacity into a material that has excellent arsenic exchange adsorption capacity.The static adsorption experiments were conducted to investigate the optimal removal condition for D296 and Zr-D401.The experimental results show that: the optimum condition for D296 is that T= 25℃,pH = 5,resin additive amount = 1 g(50 mL)-1,and contact time = 10 h,the corresponding arsenic removal rate being 65.7%,and protein loss being 2.33%;the optimum condition for Zr-D401 is that T=25℃,pH = 8,resin additive amount = 1 g(50 mL)-1,and contact time=10 h,the corresponding arsenic removal rate being 70.3%,and protein loss being 4.65%.These results show that both of the two resins are effective in arsenic removal for preserving useful substance.Our research provides scientific evidence and advances in the processing technology for heavy metal removal in shellfish.
