Objective] This study aimed to investigate the method for efficient utilization and development of purple sweet potatoes. [Method] Purple sweet potatoes were dried at two specific temperatures and prepared into prelim...Objective] This study aimed to investigate the method for efficient utilization and development of purple sweet potatoes. [Method] Purple sweet potatoes were dried at two specific temperatures and prepared into preliminarily-processed products for gelatinization simulation to analyze the extraction amount of anthocyanins from gelatinized samples at different gelatinization stages. [Result] During the gelatinization process, the extraction rate of anthocyanins from purple sweet potato samples reached the highest as the temperature rised from 90 ℃ to 95 ℃,and the extraction amount of anthocyanins reached the maximum at 15 min postheat preservation at 95 ℃. Purple sweet potato samples dried at 60 ℃ exhibited larger retention amount, larger maximum extraction amount and higher maximum extraction rate of anthocyanins compared with those dried at 110 ℃. [Conclusion] Drying at low temperatures and appropriately shortening the initial gelatinization stage below 90 ℃ is conducive to the retention and extraction of anthocyanins from purple sweet potatoes.展开更多
Hot Potatoes软件具有简便易用的特点,有助于辅助缺乏计算机技术基础的外语教师制作多种形式的网页式习题。在计算机辅助外语教学中应用Hot Potatoes能够帮助学生整合课堂与课外学习,巩固课堂所学并开展自主学习,同时还能够帮助学生适...Hot Potatoes软件具有简便易用的特点,有助于辅助缺乏计算机技术基础的外语教师制作多种形式的网页式习题。在计算机辅助外语教学中应用Hot Potatoes能够帮助学生整合课堂与课外学习,巩固课堂所学并开展自主学习,同时还能够帮助学生适应新的四六级网考评估模式。展开更多
In this study,thyme essential oil(TEO)nanoemulsion(tPTNs)was constructed with transglutaminase(TGase)-modified potato protein,and its antibacterial activity and mechanism of action were evaluated and explored.Results ...In this study,thyme essential oil(TEO)nanoemulsion(tPTNs)was constructed with transglutaminase(TGase)-modified potato protein,and its antibacterial activity and mechanism of action were evaluated and explored.Results indicated that tPTNs exhibited great antibacterial activity against both Staphylococcus aureus and Escherichia coli,with minimal inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of 2.5 and 5.0 mg/mL,respectively.Also,the antibacterial effects of tPTNs were concentration-dependent.We observed a significant decrease in the absolute value of the zeta potential,and significant increases in particle size,cell membrane hydrophobicity,conductivity,the release of metal ions,and the leakage of nucleic acid as the concentration of tPTNs increased from 0 mg/mL to MBC.Furthermore,sodium dodecyl sulphate-polyacrylamide gel electrophoresis(SDS-PAGE)demonstrated that protein synthesis was inhibited or even disrupted.Analysis by liquid chromatography-mass spectrometry(LC-MS)indicated that treatment with tPTNs caused significant changes in bacterial metabolites,1117 and 692 differential metabolites being found for S.aureus and E.coli,respectively.The differential metabolites were involved in nucleotide metabolism,amino acid metabolism,tricarboxylic acid cycle and other metabolic pathways.These findings provide valuable insights for the application of thyme essential oil as an efficient antibacterial agent and for the understanding of its mechanism of action.展开更多
Hot Potatoes是专门用来制作互动式测验练习的软件,它无需编程,只要输入文本便可以制作出Web页面的交互式测验练习,适用于学生自学及练习之用.本文作者根据个人在制作Hot Potatoes课件的实践经验,介绍该交互式练习软件的特性、制作及其...Hot Potatoes是专门用来制作互动式测验练习的软件,它无需编程,只要输入文本便可以制作出Web页面的交互式测验练习,适用于学生自学及练习之用.本文作者根据个人在制作Hot Potatoes课件的实践经验,介绍该交互式练习软件的特性、制作及其应用.展开更多
[Objective] This study aimed to analyze the contents of trace elements in potatoes from different production areas in Qinghai Province. [Method] By flame atomic absorption spectrometry （FAAS）, the contents of variou...[Objective] This study aimed to analyze the contents of trace elements in potatoes from different production areas in Qinghai Province. [Method] By flame atomic absorption spectrometry （FAAS）, the contents of various trace elements in potatoes were determined. [Result] Potatoes contain abundant trace elements such as Cu, Zn, Fe, Mn, Ca, K and Mg. To be specific, the contents of Ca, K and Mg were relatively high. [Conclusion] By using FAAS, the relative standard deviation was 1.17%-2.75% and the recovery rate was 97%-99.5%, indicating accurate and reli-able results with high precision.展开更多
Andrew Wangota,a 48-year-old Ugandan farmer,has been using agrivoltaics technology,a solar technology that uses agricultural land for both food production and solar power generation,on his farm in Bunashimolo Parish,B...Andrew Wangota,a 48-year-old Ugandan farmer,has been using agrivoltaics technology,a solar technology that uses agricultural land for both food production and solar power generation,on his farm in Bunashimolo Parish,Bukyiende Subcounty in Uganda where he has been cultivating plantain,coffee and Irish potatoes for the past 16 years.展开更多
Chemical composition(moisture,protein,starch,ash,fiber,fat),vitamins(vitamin C,vitamin B1,vitamin B2),total polyphenol content,antioxidant capacity,minerals,and amino acid of 14 potato cultivars in China were evaluate...Chemical composition(moisture,protein,starch,ash,fiber,fat),vitamins(vitamin C,vitamin B1,vitamin B2),total polyphenol content,antioxidant capacity,minerals,and amino acid of 14 potato cultivars in China were evaluated.The results indicated that all parameters varied significantly among different potato cultivars.The total starch,crude protein and fat content ranged between 57.42–67.83%,10.88–14.10% and 0.10–0.73% dry weight(DW),respectively.Moreover,the consumption of potato increased remarkably the dietary intake of vitamins,K,Mn and Cu.In addition,the chemical score of amino acid varied considerably between different cultivars,which ranged from 54(Neida 3 and Neida 41) to 71(Neida 34).Grey relational analysis(GRA) indicated that Neida 26 exhibited the most comprehensive nutritional values among potato cultivars,followed by Neida 42.Different potato flours had a significant effect on the quality parameters of potato steamed bread(PSB),Neida 26 and Neida 34 were more suitable for making PSB.展开更多
To improve the processing quality of potatoes,phosphate buffer extract(PBE),50%ethanol(E50),and aqueous extract(AE)of tartary buckwheat seedlings were evaluated for their ability to inhibit the enzymatic browning of p...To improve the processing quality of potatoes,phosphate buffer extract(PBE),50%ethanol(E50),and aqueous extract(AE)of tartary buckwheat seedlings were evaluated for their ability to inhibit the enzymatic browning of potatoes.The results suggest that all extracts of tartary buckwheat seedlings exert significant inhibitory effects on the polyphenol oxidase(PPO)activity in potatoes.The relative concentrations required for a 50%reduction in the PPO activity(IC50)were 0.21,0.28 and 0.41 mg mL^-1,for PBE,E50 and AE,respectively.The strongest inhibitory activity was observed for PBE,followed by E50 and AE.Four flavone compounds in the PBE of tartary buckwheat seedlings(i.e.,rutin,kaempferol-3-O-rutinoside,quercetin,and kaempferol)were identified by high-performance liquid chromatography.These compounds were subsequently evaluated for their roles in the inhibition of PPO from potatoes using a model system.The results indicated that rutin exhibited the highest inhibition rate on the PPO of potato.A synergistic inhibitory effect was observed by mixing rutin,kaempferol-3-Orutinoside,quercetin,and proteins.The inhibitory patterns of rutin,kaempferol-3-O-rutinoside,and quercetin on the enzyme were noncompetitive and reversible,with inhibitory constants of 0.12,0.31,and 0.40 mg mL^-1,respectively.Flavonoids from tartary buckwheat seedlings may exhibit a common mechanism with phenolic compounds,involving the blockage of the reaction of oxygen with PPO leading to the inhibition of the enzymes involved in browning.Based on these results,extracts of tartary buckwheat seedlings can be used as potent natural inhibitors.展开更多
The effects of different drying methods （hot-air drying, microwave drying and vacuum-freeze drying） on the antioxidant activity and antioxidants in sweet potato （lpomoea batatas L. Lain.） tubers were investigated ...The effects of different drying methods （hot-air drying, microwave drying and vacuum-freeze drying） on the antioxidant activity and antioxidants in sweet potato （lpomoea batatas L. Lain.） tubers were investigated to determine the potential drying process. Sweet potato tubers were cut into 5 mm thick slices, steamed at 100℃ for 10 rain, then dried in either hotair, microwave, or vacuum-freeze. The dried sweet potatoes in microwave possessed the highest antioxidant activity, while the lowest activity was observed in hot-air dried samples. The phenolic contents were positively correlated with scavenging activity and reducing power of DPPH^＋. The microwave drying retains the highest antioxidant activity with the highest content of phenolic compounds in dried sweet potatoes. β-carotene and ascorbic acid showed minor contribution to the antioxidant activity in dried sweet potatoes.展开更多
Knowledge about crop growth processes in relation to N limitation is necessary to optimize N management in farming system. Plant-based diagnostic method, for instance nitrogen nutrition index （NNI） were used to dete...Knowledge about crop growth processes in relation to N limitation is necessary to optimize N management in farming system. Plant-based diagnostic method, for instance nitrogen nutrition index （NNI） were used to determine the crop nitrogen status. This study determines the relationship of NNI with agronomic nitrogen use efficiency （AEN）, tuber yield, radiation use efficiency （RUE） and leaf parameters including leaf area index （LAI）, areal leaf N content （NJ and leaf N concentration （N0. Potatoes were grown in field at three N levels： no N （N 1）, 150 kg N ha^-1 （N2）, 300 kg N ha^-1 （N3）. N deficiency was quantified by NNI and RUE was generally calculated by estimating of the light absorbance on leaf area. NNI was used to evaluate the N effect on tuber yield, RUE, LAI, NAL, and NL. The results showed that NNI was negatively correlated with AEN, N deficiencies （NNI〈 1） which occurred for N 1 and N2 significantly reduced LAI, NL and tuber yield; whereas the N deficiencies had a relative small effect on NAL and RUE. To remove any effect other than N on these parameters, the actual ratio to maximum values were calculated for each developmental linear relationships were obtained between NNI and tuber RUE to NNI. stage of potatoes. When the NNI ranged from 0.4 to 1, positive yield, LAI, NL, while a nonlinear regression fitted the response of展开更多
Based on the combination test of various distances between ridges or plants, the influences of corresponding cultivation techniques on the per unit area yield of a variety of sweet potatoes Xushu 22 in Xianning City w...Based on the combination test of various distances between ridges or plants, the influences of corresponding cultivation techniques on the per unit area yield of a variety of sweet potatoes Xushu 22 in Xianning City were analyzed. The results show that different distances between ridges or plants had significant effects on the per unit area yield of Xushu 22; when the distances between ridges and plants for Xushu 22 planted in the city were 80 and 21 cm respectively, the per u- nit area yield of Xushu 22 was the highest, up to 48 340.7 kg/hm2.展开更多
Pigmented potato cultivars were ranked by a consumer panel for overall acceptance, and acceptance of aroma, appearance, and flavor. Potatoes were analyzed for total phenolics, anthocyanins and carotenoids. Concentrati...Pigmented potato cultivars were ranked by a consumer panel for overall acceptance, and acceptance of aroma, appearance, and flavor. Potatoes were analyzed for total phenolics, anthocyanins and carotenoids. Concentrations of total phenolics in yellow and purple potato cultivars were 2-fold greater (P P展开更多
With the detoxicated seedling of a potato cultivation breed named “Mire” as the material, the effect of auxins CCC, 6-BA, and active carbon to microtubers of potato (Solanum tubersum L.) was investigated under the i...With the detoxicated seedling of a potato cultivation breed named “Mire” as the material, the effect of auxins CCC, 6-BA, and active carbon to microtubers of potato (Solanum tubersum L.) was investigated under the in-vitro circumstances. The result indicated the exogenous auxins improved the production and quality of microtubers of potatoes. The effect of induction can be described as CCC > CCC + 6-BA > 6-BA > CK, the number of microtubers in per flask is 8.17 > 7.67 > 7.29 > 5.46, and the number of large potatoes in per flask is 6.33 > 5.17 > 3.17 > 1. In addition, by adding 0.5‰ of active charcoal, the growth period was shortened from 25.0 days to 9.33 days on average, and the amount of larger potatoes increased 8.54%. These results benefited the growth of microtubers of potato.展开更多
Effects of short-term high CO_2 pretreatment on quality of fresh-cut potatoes were studied. Potatoes were treated under 90% CO_2 for 18 h, peeled, cut, dipped in 1% ascorbic acid or distilled water for 3 min, packed i...Effects of short-term high CO_2 pretreatment on quality of fresh-cut potatoes were studied. Potatoes were treated under 90% CO_2 for 18 h, peeled, cut, dipped in 1% ascorbic acid or distilled water for 3 min, packed in polyethylene bags and stored for 12 d at 4 ℃. Non-treated potatoes were used as the control. High CO2 pretreatments ensured maintenance of a high level of CO_2 in headspace of packages containing fresh-cut potatoes. Both the growth of total aerobic bacteria in initial stages of post-cut storage and browning index of the cut surface were lower in high CO_2 treated cut potato. Anti-browning effect of high CO_2 pretreatment was decreased when applied in combination with ascorbic acid. Soluble solids, pH, titratable acidity and flesh firmness of fresh-cut potatoes were not affected by high CO_2 treatment. Therefore, high CO_2 treatment before slicing could be effective method to maintain quality of flesh-cut potatoes.展开更多
The potato (Solanum tuberosum L.) is the most important dicotyledonous source of human food. It ranks fifth major food crop of the world, exceed only by the grasses such as wheat, rice, maize, and barley. It is charac...The potato (Solanum tuberosum L.) is the most important dicotyledonous source of human food. It ranks fifth major food crop of the world, exceed only by the grasses such as wheat, rice, maize, and barley. It is characteristically a crop of the cool, temperate regions or of elevation of approximately 2,000 m or more in the tropics. It requires cool nights and well drained soil with adequate moisture and does not produce well in low altitude, warm, tropical environment. Commercial production of most potatoes is primarily through vegetative propagation by means of lateral buds formed on the tuber, a modified stem. Trough such vegetative propagation, many diseases are transmitted from generation to generation. Suppression of such diseases and reduction of yield losses due to disease are a necessary part of increasing the food supply. The principles, strategies, and tactics of plant disease management are important to preventing yield losses. Integrated pest management (IPM) may supply effective control of the potato pests including aphids (vector of some viruses), Verticillium wilt blackleg, bacterial ring rot, Rhizoctonia, Phytophthora infestans (late blight) and several weeds (night shades, pigweeds, lambs quarters, and annual grasses). It includes regular inspection for healthy seed or nursery, crop production, correct identification of the problem, cultural practices (crop rotation, sanitation etc.), biological control, soil fumigation (if necessary), seed or nursery stock treatment and disinfestations of cutting tools. In this review, pest management methods of potatoes included in IPM was summarized.展开更多
Microbial attacks during storage are one of the primary causes of product deterioration, and can limit the process of prolonging the shelf-life of harvested food. In this study, sweet potatoes were stored at temperatu...Microbial attacks during storage are one of the primary causes of product deterioration, and can limit the process of prolonging the shelf-life of harvested food. In this study, sweet potatoes were stored at temperatures of 13, 21, and 29 ℃ for 4 weeks. Samples were collected during storage and plated on potato dextrose agar, from which axenic mold cultures were obtained and identified using 26S rRNA gene sequences. Physiological changes of potato tubers were assessed with respect to pathogenicity, enzyme activity, and atmospheric storage conditions. Six fungal species were identified, namely Penicillium chrysogenum （P. rubens）, P. brevicompactum, Mucor circinelloides, C/adosporium cladosporiodes, P. expansum, and P. crustosum. The following fungal isolates, namely P. expansum, P. brevicompactum, and Rhizopus oryzae, were recovered from the re-infected samples and selected according to their levels of enzyme activity. This study revealed high levels of activity for cellulase and pectinase, which were most notable during the initial three days of testing, and were followed by a steady decrease （P〈0.05）. Polygalacturonase activity was prominent with values ranging from 12.64 to 56.79 U/mg （P. expansum） and 18.36 to 79.01 U/mg （P. brevicompactum）. Spoilage was obvious in the control group, which had a 100% decay at the end of the experimental period compared with samples treated with iprodione and sodium hypochlorite, in which the decay rates were 5% and 55%, respectively. The data for the iprodione- and sodium hypochlorite-treated samples at the end of the 3-month storage period showed that they were significantly different （P=0.041）, with the sodium hypochlorite-treated samples producing twice the rate of infection compared to the iprodione-treated samples. The comparative rate of the pro- gression of decay in the treated samples can be expressed as iprodione〈sodium hypochlorite〈control. This study demonstrates that sweet potato tissue damage is due to the activities of microbial enzymes and, in particular, the pectinases of the organisms isolated from the infected potato tissues, and suggests the advantages of utilizing iprodione as a curing agent for potato tubers before storage.展开更多
Mozambican diets are often lacking in vitamin A. Orange-fleshed sweet potatoes (OFSP) are rich in beta-carotene, a precursor of vitamin A, but are not easily introduced into the diet as the consistency of the porridge...Mozambican diets are often lacking in vitamin A. Orange-fleshed sweet potatoes (OFSP) are rich in beta-carotene, a precursor of vitamin A, but are not easily introduced into the diet as the consistency of the porridge made from OFSP is unappetising. Flour made from roasted cassava (garri) produces a palatable porridge with a high energy density. We propose a simple procedure for producing an instant porridge by roasting grated OFSP with flour from shredded sun-dried cassava (G-OFSP). This is an easily adopted variant of the traditional garri-making process. The consistency of this porridge made from milled G-OFSP (G-OFSPf) was compared to the consistency of porridges made from maize flour (Mf), cassava flour (Cf), OFSP flour (OFSPf) and garri flour (Gf) at 43°C, and then correlated to the perceived characteristics assessed by a sensory panel. The dry matter concentration of the porridges was adjusted to give similar consistency, measured by the maximum force of back extrusion, using traditional maize porridge as a reference. The porridges were additionally characterized by back extrusion force relaxation time. Short relaxation times were obtained for G-OFSPf, Mf and Gf porridges and longer times for Cf and OFSPf porridges, corresponding roughly to the sensory preference. In the sensory test of consistency, G-OFSPf porridge was ranked first, followed by Mf, Gf, OFSPf and Cf. In overall sensory tests comparing G-OFSPf porridge to Gf porridge, G-OFSPf porridge was significantly preferred with regard to all sensory attributes evaluated (p < 0.01). The energy density of the G-OFSPf porridge was 5.6 kJ/ml;the highest of the three most preferred porridges with regard to texture. The preparation of flour from a mixture of grated OFSP and shredded sun-dried cassava improved the perceived porridge consistency, increased its energy density, and its high acceptability would increase the intake of betacarotene.展开更多
基金Supported by Key Scientific and Technological Project of Wuhan Science and Technology Bureau([2012]No.100 201250499145-15)~~
文摘Objective] This study aimed to investigate the method for efficient utilization and development of purple sweet potatoes. [Method] Purple sweet potatoes were dried at two specific temperatures and prepared into preliminarily-processed products for gelatinization simulation to analyze the extraction amount of anthocyanins from gelatinized samples at different gelatinization stages. [Result] During the gelatinization process, the extraction rate of anthocyanins from purple sweet potato samples reached the highest as the temperature rised from 90 ℃ to 95 ℃,and the extraction amount of anthocyanins reached the maximum at 15 min postheat preservation at 95 ℃. Purple sweet potato samples dried at 60 ℃ exhibited larger retention amount, larger maximum extraction amount and higher maximum extraction rate of anthocyanins compared with those dried at 110 ℃. [Conclusion] Drying at low temperatures and appropriately shortening the initial gelatinization stage below 90 ℃ is conducive to the retention and extraction of anthocyanins from purple sweet potatoes.
文摘In this study,thyme essential oil(TEO)nanoemulsion(tPTNs)was constructed with transglutaminase(TGase)-modified potato protein,and its antibacterial activity and mechanism of action were evaluated and explored.Results indicated that tPTNs exhibited great antibacterial activity against both Staphylococcus aureus and Escherichia coli,with minimal inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of 2.5 and 5.0 mg/mL,respectively.Also,the antibacterial effects of tPTNs were concentration-dependent.We observed a significant decrease in the absolute value of the zeta potential,and significant increases in particle size,cell membrane hydrophobicity,conductivity,the release of metal ions,and the leakage of nucleic acid as the concentration of tPTNs increased from 0 mg/mL to MBC.Furthermore,sodium dodecyl sulphate-polyacrylamide gel electrophoresis(SDS-PAGE)demonstrated that protein synthesis was inhibited or even disrupted.Analysis by liquid chromatography-mass spectrometry(LC-MS)indicated that treatment with tPTNs caused significant changes in bacterial metabolites,1117 and 692 differential metabolites being found for S.aureus and E.coli,respectively.The differential metabolites were involved in nucleotide metabolism,amino acid metabolism,tricarboxylic acid cycle and other metabolic pathways.These findings provide valuable insights for the application of thyme essential oil as an efficient antibacterial agent and for the understanding of its mechanism of action.
文摘[Objective] This study aimed to analyze the contents of trace elements in potatoes from different production areas in Qinghai Province. [Method] By flame atomic absorption spectrometry （FAAS）, the contents of various trace elements in potatoes were determined. [Result] Potatoes contain abundant trace elements such as Cu, Zn, Fe, Mn, Ca, K and Mg. To be specific, the contents of Ca, K and Mg were relatively high. [Conclusion] By using FAAS, the relative standard deviation was 1.17%-2.75% and the recovery rate was 97%-99.5%, indicating accurate and reli-able results with high precision.
文摘Andrew Wangota,a 48-year-old Ugandan farmer,has been using agrivoltaics technology,a solar technology that uses agricultural land for both food production and solar power generation,on his farm in Bunashimolo Parish,Bukyiende Subcounty in Uganda where he has been cultivating plantain,coffee and Irish potatoes for the past 16 years.
基金financed by the National Key R&D program of China (2016YFE0133600 and 2017YFD0400401)the Collaborative Innovation Task of CAAS (CAASXTCX2016005)the Public Welfare Industry (Agriculture) Research Project,Ministry of Agriculture of China (201503001-2)
文摘Chemical composition(moisture,protein,starch,ash,fiber,fat),vitamins(vitamin C,vitamin B1,vitamin B2),total polyphenol content,antioxidant capacity,minerals,and amino acid of 14 potato cultivars in China were evaluated.The results indicated that all parameters varied significantly among different potato cultivars.The total starch,crude protein and fat content ranged between 57.42–67.83%,10.88–14.10% and 0.10–0.73% dry weight(DW),respectively.Moreover,the consumption of potato increased remarkably the dietary intake of vitamins,K,Mn and Cu.In addition,the chemical score of amino acid varied considerably between different cultivars,which ranged from 54(Neida 3 and Neida 41) to 71(Neida 34).Grey relational analysis(GRA) indicated that Neida 26 exhibited the most comprehensive nutritional values among potato cultivars,followed by Neida 42.Different potato flours had a significant effect on the quality parameters of potato steamed bread(PSB),Neida 26 and Neida 34 were more suitable for making PSB.
基金Food Processing Institute of the Guizhou Academy of Agricultural Sciences, Potato Engineering Research Center of Guizhou Province, China for the financial supportsupported by the PhD Programs Foundation of Guizhou Province ([2017]1180)+1 种基金the Youth Fund from Guizhou Academy of Agricultural Science, China ([2017]026)the Scientific and Technical Support Programs of Guizhou Province, China ([2017]2543)
文摘To improve the processing quality of potatoes,phosphate buffer extract(PBE),50%ethanol(E50),and aqueous extract(AE)of tartary buckwheat seedlings were evaluated for their ability to inhibit the enzymatic browning of potatoes.The results suggest that all extracts of tartary buckwheat seedlings exert significant inhibitory effects on the polyphenol oxidase(PPO)activity in potatoes.The relative concentrations required for a 50%reduction in the PPO activity(IC50)were 0.21,0.28 and 0.41 mg mL^-1,for PBE,E50 and AE,respectively.The strongest inhibitory activity was observed for PBE,followed by E50 and AE.Four flavone compounds in the PBE of tartary buckwheat seedlings(i.e.,rutin,kaempferol-3-O-rutinoside,quercetin,and kaempferol)were identified by high-performance liquid chromatography.These compounds were subsequently evaluated for their roles in the inhibition of PPO from potatoes using a model system.The results indicated that rutin exhibited the highest inhibition rate on the PPO of potato.A synergistic inhibitory effect was observed by mixing rutin,kaempferol-3-Orutinoside,quercetin,and proteins.The inhibitory patterns of rutin,kaempferol-3-O-rutinoside,and quercetin on the enzyme were noncompetitive and reversible,with inhibitory constants of 0.12,0.31,and 0.40 mg mL^-1,respectively.Flavonoids from tartary buckwheat seedlings may exhibit a common mechanism with phenolic compounds,involving the blockage of the reaction of oxygen with PPO leading to the inhibition of the enzymes involved in browning.Based on these results,extracts of tartary buckwheat seedlings can be used as potent natural inhibitors.
基金supported by the Science and Technology Project of Zhejiang Province,China(2009C12031)
文摘The effects of different drying methods （hot-air drying, microwave drying and vacuum-freeze drying） on the antioxidant activity and antioxidants in sweet potato （lpomoea batatas L. Lain.） tubers were investigated to determine the potential drying process. Sweet potato tubers were cut into 5 mm thick slices, steamed at 100℃ for 10 rain, then dried in either hotair, microwave, or vacuum-freeze. The dried sweet potatoes in microwave possessed the highest antioxidant activity, while the lowest activity was observed in hot-air dried samples. The phenolic contents were positively correlated with scavenging activity and reducing power of DPPH^＋. The microwave drying retains the highest antioxidant activity with the highest content of phenolic compounds in dried sweet potatoes. β-carotene and ascorbic acid showed minor contribution to the antioxidant activity in dried sweet potatoes.
基金supported by the National Key Technology R&D Program (2011BAD12B03)
文摘Knowledge about crop growth processes in relation to N limitation is necessary to optimize N management in farming system. Plant-based diagnostic method, for instance nitrogen nutrition index （NNI） were used to determine the crop nitrogen status. This study determines the relationship of NNI with agronomic nitrogen use efficiency （AEN）, tuber yield, radiation use efficiency （RUE） and leaf parameters including leaf area index （LAI）, areal leaf N content （NJ and leaf N concentration （N0. Potatoes were grown in field at three N levels： no N （N 1）, 150 kg N ha^-1 （N2）, 300 kg N ha^-1 （N3）. N deficiency was quantified by NNI and RUE was generally calculated by estimating of the light absorbance on leaf area. NNI was used to evaluate the N effect on tuber yield, RUE, LAI, NAL, and NL. The results showed that NNI was negatively correlated with AEN, N deficiencies （NNI〈 1） which occurred for N 1 and N2 significantly reduced LAI, NL and tuber yield; whereas the N deficiencies had a relative small effect on NAL and RUE. To remove any effect other than N on these parameters, the actual ratio to maximum values were calculated for each developmental linear relationships were obtained between NNI and tuber RUE to NNI. stage of potatoes. When the NNI ranged from 0.4 to 1, positive yield, LAI, NL, while a nonlinear regression fitted the response of
基金Supported by National Technical System of Sweet Potato Industry of China~~
文摘Based on the combination test of various distances between ridges or plants, the influences of corresponding cultivation techniques on the per unit area yield of a variety of sweet potatoes Xushu 22 in Xianning City were analyzed. The results show that different distances between ridges or plants had significant effects on the per unit area yield of Xushu 22; when the distances between ridges and plants for Xushu 22 planted in the city were 80 and 21 cm respectively, the per u- nit area yield of Xushu 22 was the highest, up to 48 340.7 kg/hm2.
文摘Pigmented potato cultivars were ranked by a consumer panel for overall acceptance, and acceptance of aroma, appearance, and flavor. Potatoes were analyzed for total phenolics, anthocyanins and carotenoids. Concentrations of total phenolics in yellow and purple potato cultivars were 2-fold greater (P P
文摘With the detoxicated seedling of a potato cultivation breed named “Mire” as the material, the effect of auxins CCC, 6-BA, and active carbon to microtubers of potato (Solanum tubersum L.) was investigated under the in-vitro circumstances. The result indicated the exogenous auxins improved the production and quality of microtubers of potatoes. The effect of induction can be described as CCC > CCC + 6-BA > 6-BA > CK, the number of microtubers in per flask is 8.17 > 7.67 > 7.29 > 5.46, and the number of large potatoes in per flask is 6.33 > 5.17 > 3.17 > 1. In addition, by adding 0.5‰ of active charcoal, the growth period was shortened from 25.0 days to 9.33 days on average, and the amount of larger potatoes increased 8.54%. These results benefited the growth of microtubers of potato.
文摘Effects of short-term high CO_2 pretreatment on quality of fresh-cut potatoes were studied. Potatoes were treated under 90% CO_2 for 18 h, peeled, cut, dipped in 1% ascorbic acid or distilled water for 3 min, packed in polyethylene bags and stored for 12 d at 4 ℃. Non-treated potatoes were used as the control. High CO2 pretreatments ensured maintenance of a high level of CO_2 in headspace of packages containing fresh-cut potatoes. Both the growth of total aerobic bacteria in initial stages of post-cut storage and browning index of the cut surface were lower in high CO_2 treated cut potato. Anti-browning effect of high CO_2 pretreatment was decreased when applied in combination with ascorbic acid. Soluble solids, pH, titratable acidity and flesh firmness of fresh-cut potatoes were not affected by high CO_2 treatment. Therefore, high CO_2 treatment before slicing could be effective method to maintain quality of flesh-cut potatoes.
文摘The potato (Solanum tuberosum L.) is the most important dicotyledonous source of human food. It ranks fifth major food crop of the world, exceed only by the grasses such as wheat, rice, maize, and barley. It is characteristically a crop of the cool, temperate regions or of elevation of approximately 2,000 m or more in the tropics. It requires cool nights and well drained soil with adequate moisture and does not produce well in low altitude, warm, tropical environment. Commercial production of most potatoes is primarily through vegetative propagation by means of lateral buds formed on the tuber, a modified stem. Trough such vegetative propagation, many diseases are transmitted from generation to generation. Suppression of such diseases and reduction of yield losses due to disease are a necessary part of increasing the food supply. The principles, strategies, and tactics of plant disease management are important to preventing yield losses. Integrated pest management (IPM) may supply effective control of the potato pests including aphids (vector of some viruses), Verticillium wilt blackleg, bacterial ring rot, Rhizoctonia, Phytophthora infestans (late blight) and several weeds (night shades, pigweeds, lambs quarters, and annual grasses). It includes regular inspection for healthy seed or nursery, crop production, correct identification of the problem, cultural practices (crop rotation, sanitation etc.), biological control, soil fumigation (if necessary), seed or nursery stock treatment and disinfestations of cutting tools. In this review, pest management methods of potatoes included in IPM was summarized.
文摘Microbial attacks during storage are one of the primary causes of product deterioration, and can limit the process of prolonging the shelf-life of harvested food. In this study, sweet potatoes were stored at temperatures of 13, 21, and 29 ℃ for 4 weeks. Samples were collected during storage and plated on potato dextrose agar, from which axenic mold cultures were obtained and identified using 26S rRNA gene sequences. Physiological changes of potato tubers were assessed with respect to pathogenicity, enzyme activity, and atmospheric storage conditions. Six fungal species were identified, namely Penicillium chrysogenum （P. rubens）, P. brevicompactum, Mucor circinelloides, C/adosporium cladosporiodes, P. expansum, and P. crustosum. The following fungal isolates, namely P. expansum, P. brevicompactum, and Rhizopus oryzae, were recovered from the re-infected samples and selected according to their levels of enzyme activity. This study revealed high levels of activity for cellulase and pectinase, which were most notable during the initial three days of testing, and were followed by a steady decrease （P〈0.05）. Polygalacturonase activity was prominent with values ranging from 12.64 to 56.79 U/mg （P. expansum） and 18.36 to 79.01 U/mg （P. brevicompactum）. Spoilage was obvious in the control group, which had a 100% decay at the end of the experimental period compared with samples treated with iprodione and sodium hypochlorite, in which the decay rates were 5% and 55%, respectively. The data for the iprodione- and sodium hypochlorite-treated samples at the end of the 3-month storage period showed that they were significantly different （P=0.041）, with the sodium hypochlorite-treated samples producing twice the rate of infection compared to the iprodione-treated samples. The comparative rate of the pro- gression of decay in the treated samples can be expressed as iprodione〈sodium hypochlorite〈control. This study demonstrates that sweet potato tissue damage is due to the activities of microbial enzymes and, in particular, the pectinases of the organisms isolated from the infected potato tissues, and suggests the advantages of utilizing iprodione as a curing agent for potato tubers before storage.
文摘Mozambican diets are often lacking in vitamin A. Orange-fleshed sweet potatoes (OFSP) are rich in beta-carotene, a precursor of vitamin A, but are not easily introduced into the diet as the consistency of the porridge made from OFSP is unappetising. Flour made from roasted cassava (garri) produces a palatable porridge with a high energy density. We propose a simple procedure for producing an instant porridge by roasting grated OFSP with flour from shredded sun-dried cassava (G-OFSP). This is an easily adopted variant of the traditional garri-making process. The consistency of this porridge made from milled G-OFSP (G-OFSPf) was compared to the consistency of porridges made from maize flour (Mf), cassava flour (Cf), OFSP flour (OFSPf) and garri flour (Gf) at 43°C, and then correlated to the perceived characteristics assessed by a sensory panel. The dry matter concentration of the porridges was adjusted to give similar consistency, measured by the maximum force of back extrusion, using traditional maize porridge as a reference. The porridges were additionally characterized by back extrusion force relaxation time. Short relaxation times were obtained for G-OFSPf, Mf and Gf porridges and longer times for Cf and OFSPf porridges, corresponding roughly to the sensory preference. In the sensory test of consistency, G-OFSPf porridge was ranked first, followed by Mf, Gf, OFSPf and Cf. In overall sensory tests comparing G-OFSPf porridge to Gf porridge, G-OFSPf porridge was significantly preferred with regard to all sensory attributes evaluated (p < 0.01). The energy density of the G-OFSPf porridge was 5.6 kJ/ml;the highest of the three most preferred porridges with regard to texture. The preparation of flour from a mixture of grated OFSP and shredded sun-dried cassava improved the perceived porridge consistency, increased its energy density, and its high acceptability would increase the intake of betacarotene.
