Dry corn straw(DCS)is usually used in anaerobic digestion(AD),but fresh corn straw(FCS)has been given less consideration.In this study,the thermophilic AD of single-substrate(FCS and DCS)and co-digestion(straw with ca...Dry corn straw(DCS)is usually used in anaerobic digestion(AD),but fresh corn straw(FCS)has been given less consideration.In this study,the thermophilic AD of single-substrate(FCS and DCS)and co-digestion(straw with cattle manure)were investigated.The results show that when FCS was used as the single-substrate for AD,the methane production was 144 mL·g^(−1)·VS^(−1),which was 7.5%and 19.6%higher than that of single DCS and FCS with cattle manure,respectively.In addition,the structure of FCS was loose and coarse,which was easier to be degraded than DCS.At the hydrolysis and acidification stages,Clostridium_sensu_stricto_1,Clostridium_sensu_stricto_7 and Sporosarcina promoted the decomposition of organic matter,leading to volatile fatty acids(VFAs)accumulation.Methanosarcina(54.4%)activated multifunctional methanogenic pathways to avoid the VFAs inhibition,which was important at the CH_(4) production stage.The main pathway was hydrogenotrophic methanogenesis,with genes encoding formylmethanofuran dehydrogenase(K00200-K00203)and tetrahydromethanopterin Smethyltransferase(K00577-K00584).Methanosarcina also activated acetotrophic and methylotrophic methanogenesis pathways,with genes encoding acetyl phosphate(K13788)and methyl-coenzyme M reductase(K04480,K14080 and K14081),respectively.In the co-digestion,the methanogenic potential of FCS was also confirmed.This provides a scientific basis for regulating AD of crop straw.展开更多
Understanding of moisture changes in fresh ear corn(Zea mays L.)during storage is imperative for maintaining fresh corn quality.The changes of moisture distribution and migration in fresh ear corn during storage were ...Understanding of moisture changes in fresh ear corn(Zea mays L.)during storage is imperative for maintaining fresh corn quality.The changes of moisture distribution and migration in fresh ear corn during storage were investigated using low-field nuclear magnetic resonance(NMR)and magnetic resonance imaging(MRI).Water loss was greater than water migration in fresh ear corn within the first hour of storage;thereafter,water loss was weaker than water migration.With the extension of storage time,the signal intensity of MRI in different parts of sliced fresh corn with cob showed a downward trend,and the rate of signal intensity reduction was higher in the peripheral area than at the central part of sliced fresh corn with cob.The relative proportion of bound water increased with a concomitant drop in that of free water,when the total water content reduced in fresh ear corn under storage.In conclusion,NMR and MRI are useful and non-destructive tools for real-time monitoring of moisture distribution,migration,and loss in fresh ear corn during storage to assess its quality.These results can be used for future design of the preserving and processing conditions for fresh ear corn.展开更多
Objective] This study aimed to detect al organophosphate, organochlorine and pyrethroid pesticide residues in fresh sweet corn in one determination using a gas chromatograph. [Method] The pesticide residues in fresh s...Objective] This study aimed to detect al organophosphate, organochlorine and pyrethroid pesticide residues in fresh sweet corn in one determination using a gas chromatograph. [Method] The pesticide residues in fresh sweet corn were ex-tracted and loaded to simultaneously the gas chromatograph Agilent 6890N which was equipped with two autosamplers, two columns and two detectors. [Result] Al the 26 pesticides were completely separated and eluted out within 25 min. The re-coveries of standard addition of the 26 pesticides ranged from 76% to 106%, with relative standard deviations （RSD） ranging from 0.5% to 8.9%. The linear regression equation fit wel from 0.050 to 1.500 mg/L corn extract （r2＆gt;0.996）. [Conclusion] The method is accuracy, which meets the requirements of pesticide residue analysis and can be used for the rapid detection, qualitative and quantitative analysis of pesticide residues in fresh sweet corn.展开更多
以提取的玉米秸秆纤维素为原料制备羧甲基纤维素,在其中添加甘油和不同浓度的AgNO_(3)后制得改性复合膜。通过扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、热重分析(TGA)、傅里叶红外光谱(FT-IR)对改性复合膜进行结构...以提取的玉米秸秆纤维素为原料制备羧甲基纤维素,在其中添加甘油和不同浓度的AgNO_(3)后制得改性复合膜。通过扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、热重分析(TGA)、傅里叶红外光谱(FT-IR)对改性复合膜进行结构和形貌表征,结果表明:改性复合膜质地均匀,部分Ag^(+)以单质银的形式与膜中的成分相互作用,膜热稳定性良好,满足保鲜材料要求。改性复合膜对大肠杆菌(E.coli)及白色葡萄球菌(S.albus)的抑制情况进一步证明了其中存在单质Ag粒子,对S.albus的抑制能力更强。用改性复合膜包裹蓝莓,存储10 d后的失重率低于7%、颜色几乎没有变化;可溶性固形物损失小于3%、可滴定酸下降不明显,当加入1 mL 0.01 mol/LAgNO_(3)时,改性复合膜的保鲜性能相对较好。展开更多
基金supported by the Shaanxi Youth Thousand Talents Project(A279021901)the Scientific and Technological Activities for Overseas Researchers in Shaanxi Province(20200002)+3 种基金the Chinese Universities Scientific Fund(2452021112)the Key Research and Development Project of Shaanxi Province(2020NY-114)the Double first-class construction project funded by Northwest A&F University,Northwest A&F University Young Talent Project(Z111021902)the USA Energy Foundation(G-2206-33957).
文摘Dry corn straw(DCS)is usually used in anaerobic digestion(AD),but fresh corn straw(FCS)has been given less consideration.In this study,the thermophilic AD of single-substrate(FCS and DCS)and co-digestion(straw with cattle manure)were investigated.The results show that when FCS was used as the single-substrate for AD,the methane production was 144 mL·g^(−1)·VS^(−1),which was 7.5%and 19.6%higher than that of single DCS and FCS with cattle manure,respectively.In addition,the structure of FCS was loose and coarse,which was easier to be degraded than DCS.At the hydrolysis and acidification stages,Clostridium_sensu_stricto_1,Clostridium_sensu_stricto_7 and Sporosarcina promoted the decomposition of organic matter,leading to volatile fatty acids(VFAs)accumulation.Methanosarcina(54.4%)activated multifunctional methanogenic pathways to avoid the VFAs inhibition,which was important at the CH_(4) production stage.The main pathway was hydrogenotrophic methanogenesis,with genes encoding formylmethanofuran dehydrogenase(K00200-K00203)and tetrahydromethanopterin Smethyltransferase(K00577-K00584).Methanosarcina also activated acetotrophic and methylotrophic methanogenesis pathways,with genes encoding acetyl phosphate(K13788)and methyl-coenzyme M reductase(K04480,K14080 and K14081),respectively.In the co-digestion,the methanogenic potential of FCS was also confirmed.This provides a scientific basis for regulating AD of crop straw.
基金supported by the National Natural Science Foundation of China (31171760)the National Public Welfare Industry Research Project of China (201313011-3)the National Corn Industry Technology System of China (CARS-02-29)
文摘Understanding of moisture changes in fresh ear corn(Zea mays L.)during storage is imperative for maintaining fresh corn quality.The changes of moisture distribution and migration in fresh ear corn during storage were investigated using low-field nuclear magnetic resonance(NMR)and magnetic resonance imaging(MRI).Water loss was greater than water migration in fresh ear corn within the first hour of storage;thereafter,water loss was weaker than water migration.With the extension of storage time,the signal intensity of MRI in different parts of sliced fresh corn with cob showed a downward trend,and the rate of signal intensity reduction was higher in the peripheral area than at the central part of sliced fresh corn with cob.The relative proportion of bound water increased with a concomitant drop in that of free water,when the total water content reduced in fresh ear corn under storage.In conclusion,NMR and MRI are useful and non-destructive tools for real-time monitoring of moisture distribution,migration,and loss in fresh ear corn during storage to assess its quality.These results can be used for future design of the preserving and processing conditions for fresh ear corn.
基金Supported by Science and Technology Research Program of Huizhou City~~
文摘Objective] This study aimed to detect al organophosphate, organochlorine and pyrethroid pesticide residues in fresh sweet corn in one determination using a gas chromatograph. [Method] The pesticide residues in fresh sweet corn were ex-tracted and loaded to simultaneously the gas chromatograph Agilent 6890N which was equipped with two autosamplers, two columns and two detectors. [Result] Al the 26 pesticides were completely separated and eluted out within 25 min. The re-coveries of standard addition of the 26 pesticides ranged from 76% to 106%, with relative standard deviations （RSD） ranging from 0.5% to 8.9%. The linear regression equation fit wel from 0.050 to 1.500 mg/L corn extract （r2＆gt;0.996）. [Conclusion] The method is accuracy, which meets the requirements of pesticide residue analysis and can be used for the rapid detection, qualitative and quantitative analysis of pesticide residues in fresh sweet corn.
文摘以提取的玉米秸秆纤维素为原料制备羧甲基纤维素,在其中添加甘油和不同浓度的AgNO_(3)后制得改性复合膜。通过扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、热重分析(TGA)、傅里叶红外光谱(FT-IR)对改性复合膜进行结构和形貌表征,结果表明:改性复合膜质地均匀,部分Ag^(+)以单质银的形式与膜中的成分相互作用,膜热稳定性良好,满足保鲜材料要求。改性复合膜对大肠杆菌(E.coli)及白色葡萄球菌(S.albus)的抑制情况进一步证明了其中存在单质Ag粒子,对S.albus的抑制能力更强。用改性复合膜包裹蓝莓,存储10 d后的失重率低于7%、颜色几乎没有变化;可溶性固形物损失小于3%、可滴定酸下降不明显,当加入1 mL 0.01 mol/LAgNO_(3)时,改性复合膜的保鲜性能相对较好。
