Degradation, under non-oxygen-mediated autooxidation, of carotenoid profile present in paprika oleoresins with lipid substrates of different fatty acid composition

A heat-induced degradation was carried out over two crude paprika oleoresins diluted with high oleic or high linoleic oil. Occurrence of oxygen was avoided, and changes in individual carotenoids were followed over time. Degradation rate constants were not significantly different, so that carotenoid stability was not linked with unsaturation degree of the oily system. A parallel reaction to degradation, trans to cis carotenoid isomer conversion, was also denoted during the thermal treatment, and it initially showed a higher rate than degradation of cis-isomers. Both processes (isomerization and cis-isomers degradation) were finally compensated, and their development was also unaffected by the nature of the lipid profile. Under the reaction conditions, oleic and linoleic fatty acids showed the same reactivity and induced degradative reactions, equally affecting the carotenoid profile. An enhanced stability of carotenoid content and provitamin A value was not achieved with a decrease in the unsaturation level of the oily system.     

Rapid spectrophotometric determination of red and yellow isochromic carotenoid fractions in paprika and red pepper oleoresins

A rapid method has been developed for the determination of the red (R) and yellow (Y) isochromic carotenoid pigments fractions in paprika and oleoresins, based on UV-visible spectrophotometric measurement at two characteristic wavelengths and application of the Lambert-Beer law for multicomponent mixtures. The wavelengths 472 and 508 nm were selected as the most appropriate for simultaneous quantification of these fractions in the acetone extract of pigments. Experimental determination of the specific absorption coefficients (epsilon) for the two pigment fractions (R, Y) at 472 and 508 nm yielded equations to calculate the concentration of the two fractions, the total pigment content, and the ratio between the two fractions. The error in the determination of the isochromic fractions by the proposed spectrophotometric method was <5% when the results were compared with those obtained by HPLC analysis. The method can be applied to the direct extract of pigments, thereby avoiding saponification and minimizing errors from pigment degradation and sample manipulation as well as shortening the time of analysis (5 min in the case of oleoresins).     

Quantitaive and qualitative changes associated with heat treatments in the carotenoid content of paprika oleoresins.

Quantitative changes in the red and yellow carotenoid pigment fractions of four paprika oleoresins were studied at four storage temperatures. At all four temperatures, there was an overall loss of pigmentation, which was more marked with increasing temperature. However, pigmentation loss was not qualitatively uniform. At temperatures below 60 degrees C, the rate of destruction of the yellow pigment fraction was higher than that of the red pigments. Above 60 degrees C, the order of lability of the two fractions was inverted and the red pigment fraction became the more unstable. Thus, treatments above this temperature increase the proportion of yellow pigments. Any heat treatment results in a decrease in the total pigment concentration, with the initial proportion of red and yellow pigments switching in favor of one or the other depending on the temperature used.     

Prediction of decoloration in paprika oleoresins. Application to studies of stability in thermodynamically compensated systems.

In six paprika oleoresins, the kinetic parameters for the decoloration reaction at three temperatures have been established. The thermodynamic study shows that the decoloration reaction in each oleoresin has its own activation entropy (DeltaS) and activation enthalpy (DeltaH). The six reactions studied show a constant ratio between DeltaH and DeltaS, which means that each reaction is an isokinetic form of only one reaction affected by thermodynamic compensation. Instead of one equation per oleoresin to predict pigment concentration as a mathematical function of time and temperature, one unique equation can be obtained in which DeltaH is a function of DeltaS. The validity of this equation has been tested by comparing the actual concentration remaining during a heat treatment and the calculated one. More than 90% of the calculated concentrations are within the range of variability of the actual mean. Due to the reduction in the number of variables in thermodynamic compensated systems, a general procedure to calculate the activation entropy in isokinetic reactions is proposed.     

Thermal degradation products formed from carotenoids during a heat-induced degradation process of paprika oleoresins (Capsicum annuum L.)

The high-temperature treatment of paprika oleoresins (Capsicum annuum L.) modified the carotenoid profile, yielding several degradation products, which were analyzed by HPLC-APCI-MS. From the initial MS data, compounds were grouped in two sets. Set 1 grouped compounds with m/z 495, and set 2 included compounds with m/z 479, in both cases for the protonated molecular mass. Two compounds of the first set were tentatively identified as 9,10,11,12,13,14,19,20-octanor-capsorubin (compound II) and 9,10,11,12,13,14,19,20-octanor-5,6-epoxide-capsanthin (compound IV), after isolation by semipreparative HPLC and analysis by EI-MS. Compounds VII, VIII, and IX from set 2 were assigned as 9,10,11,12,13,14,19,20-octanor-capsanthin and isomers, respectively. As these compounds were the major products formed in the thermal process, it was possible to apply derivatization techniques (hydrogenation and silylation) to analyze them by EI-MS, before and after chemical derivatization. Taking into account structures of the degradation products, the cyclization of polyolefins could be considered as the general reaction pathway in thermally induced reactions, yielding in the present study xylene as byproduct and the corresponding nor-carotenoids.     

Microbial inactivation of paprika by a high-temperature short-X time treatment. Influence on color properties

High-temperature short-time (HTST) treatments have been used to destroy the bioburden of paprika. With this in mind, we have designed a device to treat samples of paprika with a gas whose temperature, pressure, and composition can be selected. Temperatures and treatment times ranged from 130 to 170 degrees C and 4 to 6 s, respectively. The survival of the most commonly found microorganisms in paprika and any alteration in extractable and superficial color were examined. Data showed that the optimum HTST conditions were 145 degrees C, 1.5 kg/cm2 of overpressure, 6 s operation time, and a thermal fluid of saturated steam. No microbial growth was detected during storage after thermal treatment. To minimize the color losses, treated (HTST) paprika samples should be kept under refrigeration.     

高温对小白菜品质的影响及模拟研究

为了研究高温胁迫对小白菜品质指标的影响,以‘华王’为试材,于2015年10月—2016年5月进行分批播种试验,设置昼温/夜温为32℃/22℃、35℃/25℃、38℃/28℃共3个梯度,持续处理时间分别为3 d、6 d、9 d、12 d,以25℃/18℃为对照(CK)。各处理结束2 d后测定小白菜外观形态、SPAD值、单株干鲜重和粗纤维、可溶性糖、可溶性蛋白、维C的含量,建立小白菜卷叶率和单位面积产量与最高气温、最低气温、平均气温及持续时间的回归模型,并用实测数据检验模型的模拟效果。结果表明:小白菜单株干重、鲜重、叶片鲜重、叶片长度、叶片宽度、叶柄宽度、SPAD和单位面积产量均随高温胁迫的加剧和胁迫时间的延长而呈降低趋势。随温度的升高和持续时间的延长,叶片内叶柄长度、卷叶率逐渐增加。高温胁迫使小白菜粗纤维含量升高。短期高温胁迫下可溶性糖、可溶性蛋白、维C含量变化不明显,随胁迫时间的延长、胁迫温度升高逐渐降低。通过多元回归方法,分别构建了小白菜卷叶率和单位面积产量与最高处理气温、最低处理气温、平均处理气温及各处理所对应持续时间的关系模型。对模型的检验结果表明,小白菜卷叶率与最低处理温度和最低温度持续时间构建模型模拟效果最好,回归估计标准误差和相对误差分别为7.59%和0.189 4;单位面积产量与最高处理温度和最高温度持续时间构建模型模拟效果最好,回归估计标准误差和相对误差分别为274.02 g·m-2和0.073%。研究认为随高温胁迫强度加剧、胁迫时间延长,小白菜产量降低,口感变差,营养物质含量减少,说明高温胁迫使小白菜品质变差。     

Effect of hydrodynamics factors on sediment flocculation processes in estuaries

Purpose

Cohesive sediment is able to flocculate and create flocs, which are larger than individual particles and less dense. The phenomenon of flocculation has an important role in sediment transport processes such as settling, deposition and erosion. In this study, laboratory experiments were performed to investigate the effect of key hydrodynamic parameters such as suspended sediment concentration and salinity on floc size and settling velocity. Results were compared with previous laboratory and field studies at different estuaries.

Materials and methods

Experimental tests were conducted in a 1-L glass beaker of 11-cm diameter using suspended sediment samples from the Severn Estuary. A particle image velocimetry system and image processing routine were used to measure the floc size distribution and settling velocity.

Results and discussion

The settling velocity was found to range from 0.2 to 1.2 mm s^?1. Settling velocity changed in the case of increasing suspended sediment concentration and was controlled by the salinity. The faster settling velocity occurred when sediment concentration is higher or the salinity is lower than 2.5. On the other hand, at salinities higher than 20, in addition to increasing SSC, it was found that the situation was reversed, i.e. the lower the sediment concentration, the faster the settling velocity.

Conclusions

Sediment flocculation is enhanced with increasing sediment concentration but not with increasing salinity.

     

Carotenoid composition in the fruits of red paprika (Capsicum annuum var. lycopersiciforme rubrum) during ripening; biosynthesis of carotenoids in red paprika

The changes in the carotenoid pigments of the Capsicum annuum var. lycopersiciforme rubrum during maturation have been investigated quantitatively by means of a HPLC technique. In all of the chromatograms, 40 peaks were detected; 34 carotenoids were identified. The total carotenoid content of the ripe fruits was about 1.3 g/100 g of dry weight, of which capsanthin constituted 37%, zeaxanthin was 8%, cucurbitaxanthin A was 7%, capsorubin constituted 3.2%, and beta-carotene accounted for 9%. The remainder was composed of capsanthin 5,6-epoxide, capsanthin 3,6-epoxide, 5,6-diepikarpoxanthin, violaxanthin, antheraxanthin, beta-cryptoxanthin, and several cis isomers and furanoid oxides. The possible biosynthetic routes for the formation of minor carotenoids containing 3,5,6-trihydroxy-beta-, 3,6-epoxy-beta-, and 6-hydroxy-gamma-end groups are described.     

Influences of gamma-irradiation and storage on the carotenoids of sun-dried and dehydrated paprika

The effects of drying methods, gamma-irradiation, and storage on the carotenoids (capsanthin, capsorubin, zeaxanthin, capsolutein, violaxanthin, beta-carotene, and beta-cryptoxanthin) of paprika were investigated. Sun-dried and dehydrated paprika samples were irradiated in a (60)Co gamma-irradiator at five doses (0, 2.5, 5.0, 7.5, and 10 kGy) in polyethylene bags and stored for 10 months at ambient temperature. Individual carotenoid analyses were carried out on the paprika and fresh red pepper during a 2 month period using the reverse phase HPLC technique. The concentrations of capsanthin and capsorubin, which are responsible for the attractive red color of sun-dried paprika, were higher than those of dehydrated paprika. Higher irradiation doses and a longer storage period resulted in a significant (P < 0.01) reduction of all the carotenoids, except capsorubin. There was no significant (P < 0.05) effect of irradiation dose on capsorubin destruction. The decrease of red carotenoids, for all irradiation treatments, was less than that of the storage period. Even the highest irradiation dose, 10 kGy, caused a 11.1% capsanthin reduction; however, 10 months of storage at the ambient temperature caused a 42.1% reduction of capsanthin. Yellow pigments of paprika (zeaxanthin, capsolutein, violaxanthin, beta-carotene, and beta-cryptoxanthin) were significantly (P < 0.01) decreased by all treatments. These yellow pigments were also found to be at high levels in those sun-dried samples with red pigments. This difference could be caused by the contribution of pigment biosynthesis during the sun-drying period. The most significant pigment reduction was realized in the processing and storage conditions of paprika, rather than in the irradiation process.     

Impact of heavy metals on the degradative capabilities of soil bacterial communities

The degradative capabilities of six heavy-metal-affected and six unaffected bacterial communities from Canadian and German soils were determined by enumerating colony-forming units on 20 specific media. Each of these contained an aromatic substrate as the sole source of C and energy. Comparisons of plate counts revealed that heavy metal stress caused a decrease in the eveness of the distribution of the 20 degradative capabilities This suggests that in heavy-metal-affected bacterial communities, relatively rare degradative capabilities, irrespective of their nature, are even rarer than in unaffected communities, while the reverse is true for more common capabilities. The results are discussed with respect to the ease with which aromatic substrates can serve as C and energy sources.     

Factors affecting transfer of degradative plasmids between bacteria in soils

Horizontal gene transfer is useful for enhancing bioremediation through gene bioaugmentation. However, factors affecting transfer of degradative plasmids have not been systematically addressed. To this end, plasmid transfer experiments were performed using a TOL-like plasmid carrying the gene encoding for catechol 2,3-dioxygenase (C23O) between two soil bacteria under different conditions. Transfer frequency increased with air temperature in the range of 10–35 °C and reached 6 × 10⁻⁴ transconjugants per donor cell at 35 °C. The transfer frequency detected at soil depth 5–10 cm was significantly higher (p < 0.05) compared with other depths. Addition of 5–75% LB in the microbial inoculum promoted plasmid transfer frequencies. Addition of phenol to the experimental system resulted in significantly higher transfer frequency (p < 0.05) compared with no addition. Transfer frequency heat-moisture in loam was significantly higher (p < 0.05) than in other soils. The highest transfer frequency was found in the experiment containing tomato seedlings, with up to about 1.3 × 10⁻³ transconjugants per donor cell. Corn and wheat seedlings also led to significantly higher transfer frequencies (p < 0.05) compared with no plants. Furthermore, C23O activities of transconjugants formed under different conditions were measured, as a surrogate measure of the activity of transconjugant. Transfer temperature, soil and plant types had a minor influence on activities of transconjugants. Topsoil (0–5 cm) transconjugants expressed C23O more efficiently under normal incubation condition, but less efficiently when soils incubated with excessive LB medium concentrations, and in the absence of phenol in soil. These results suggested that transfer temperature, soil depth, dilutions of LB broth, phenol content, and soil and plant types had important effects on transfer of the TOL-like plasmid in soil, and some factors also affected activities of transconjugants.     

Discovery of environmental rhodamine B contamination in paprika during the vegetation process

Recently, rhodamine B (RhB) in paprika and chilli has attracted much attention. Almost all the literature has deemed that the detectable RhB was attributed to malicious intents in the fabrication process. However, the occurrence of increasing cases with ultratrace levels of RhB was difficult to understand on the basis of that statement. Here, we report on the discovery of environmental RhB contamination in paprika during its vegetation process. Samples including paprika, soils, and stems collected from seven fields in the Xinjiang Region, China, were detected by ultraperformance liquid chromatography-tandem mass spectrometry. Far from any anthropogenic addition, the ultratrace RhB concentrations in all the paprika samples provided unambiguous evidence that environmental RhB contamination in paprika had really occurred over its growth period. Further illation suggests that the soil contaminated by RhB is one of the major contamination sources and that there may be a degradation of RhB in paprika during the late maturation stage. The discovery has significant implications for re-evaluating the origin of the RhB in paprika- and chilli-containing products.     

Effects of paprika pigments on oxidation of linoleic acid stored in the dark or exposed to light

We examined the antioxidant effects of paprika pigments on oxidation of linoleic acid and on decoloration of the sample when stored at 37 degrees C in the dark or exposed to fluorescent light for 8 h per day. (1)H nuclear magnetic resonance with dioxane as an external proton reference was used to estimate the oxidative deterioration of linoleic acid. Oxidation was estimated by observing the ratio of the divinylmethylene proton signal area in linoleic acid vs the proton signal area in dioxane. The addition of paprika pigments suppressed the oxidation of linoleic acid during storage in the dark, and the effect was markedly increased with increasing concentrations (0.02, 0.2, and 2%). When the linoleic acid with added paprika pigments was exposed to light, only a slight suppression of oxidation was observed, and the color of the sample disappeared more rapidly than that in the dark. At the time of decoloration of the sample with added pigments, considerable oxidation of linoleic acid occurred. As the color change is due to degradation of the pigment, an increase in oxidation at the time of discoloration is consistent with the pigments functioning as antioxidants. The addition of alpha-tocopherol to paprika pigments stabilized degradation of the pigments by light. Although the addition of alpha-tocopherol to linoleic acid with added paprika pigments prolonged the decoloration of the sample under light, the prevention of oxidation under the light condition was not as effective as for the samples stored in the dark.     

高温胁迫对4种珍珠菜属植物抗性生理生化指标的影响

为探明珍珠菜属植物高温致伤的生理特性,为其园林推广提供依据,以4种珍珠菜属植物为材料,通过盆栽在人工气候箱内进行高温胁迫,研究了不同程度高温胁迫对4种珍珠菜属植物叶片的质膜透性、保护酶活性和渗透调节物质的影响.结果表明:随高温胁迫的加强,叶片的质膜透性上升;超氧化物歧化酶(SOD)、过氧化物酶(POD)活性先上升,后下降;叶绿素总量、脯氨酸含量、可溶性蛋白含量在一定程度内均增加,只是变化的幅度和进程不同.经几项生理指标的综合分析,得出广西过路黄(Lyaimachia alfredii)和花叶过路黄(L.christinae var huaye)的耐高温能力较强,金叶过路黄(L.nummularia ‘Aurea')与聚花过路黄(L.congestiflora)的耐高温能力较弱.     

高温复合菌系WSC-6预处理稻秆对沼气生产的影响

为提高稻秆在沼气生产中的水解酸化效率,寻求复合菌系WSC-6生长的廉价氮源,降低稻秆酸化水解的运行成本,该试验利用高温复合菌系WSC-6,以未经处理的稻秆为碳源,分别以新鲜猪粪和干猪粪为氮源,对稻秆进行生物预处理。研究结果表明,高温复合菌系WSC-6对新鲜猪粪中的氮源利用更充分,总氮利用率达到81.5%,对稻秆的降解率也高于干猪粪,稻秆的总质量损失率达到48.3%,纤维素、半纤维素和木质素的降解率分别达到67.3%、79.3%和27.9%。在稻秆的生物预处理中,无论采用哪种氮源方式,反应系统的pH值都在6.5～8.2之间变化,不会产生酸化现象。以新鲜猪粪代替蛋白胨作为稻秆生物预处理的氮源,既降低了稻秆生物预处理的运行成本,又消除了猪粪造成的环境污染,这对沼气的工业化生产具有重要的应用价值。     

模拟降雨条件下作物植株对降雨再分配过程的影响

为系统测定玉米（Zea mays L.）、大豆（Glycine max）、谷子（Setaria italica）和冬小麦（Triticum aestivum Linn.）不同生长阶段的穿透雨、茎秆流和冠层截留,研究采用室内模拟降雨法测定了不同降雨强度、不同叶面积指数作物冠下穿透雨和茎秆流,采用喷雾法测定了作物不同生长阶段的冠层截留。对其进行了量化分析,并探讨了3者与作物叶面积指数和降雨强度的关系。结果表明：在40和80 mm/h降雨强度下降雨30 min,玉米、大豆、谷子和冬小麦冠下穿透雨率分别平均为65.15%、85.52%、80.05%和72.18%;在40和80 mm/h降雨强度下降雨10～20 min,4种茎秆流率分别平均为34.59%、13.58%、19.42%和26.34%;在0.3 mm/min喷雾强度下,作物冠层截留量相对较小,冠层截留率分别为0.26%、0.90%、0.53%和1.48%。随作物生长,穿透雨量逐渐降低,茎秆流量和冠层截留量逐渐增加。降雨强度与穿透雨量和茎秆流量呈正相关关系,但是2者占总降雨量的比例与降雨强度关系不显著（p＞0.05）。随着作物生长,穿透雨冠下空间分布由均匀逐渐趋向于不均匀,具有趋于向行中汇集的趋势。该研究揭示了黄土高原地区主要作物对降雨的再分配作用特征,可为农田水分有效利用和坡耕地土壤侵蚀防治提供理论依据。     

Effect of indaziflam on microbial activity and nitrogen cycling processes in an orchard soil

Indaziflam is a preemergent herbicide widely used for the control of weeds in pecan (Carya illinoinensis) orchards in the southwestern region of the United States. Given the paucity of data regarding the effect of indaziflam on the biochemical properties of soils supporting pecan production, this study was conducted to evaluate the effects of different application rates of indaziflam on soil microbial activity, diversity, and biochemical processes related to nitrogen (N) cycling. During two consecutive growing seasons (2015 and 2016), soil samples were obtained from experimental mesocosms consisting of soil-filled pots where pecan saplings were grown and treated with indaziflam applied at two different rates (25 and 50 g active ingredient (ai) ha^-1, with the higher rate being slightly lower than the recommended field application rate of 73.1 g ai ha^-1). Soil samples were collected approximately one week before and one week after herbicide application for determination of soil microbial biomass and diversity, N mineralization, and β-glucosaminidase activity. Soil samples collected from the control mesocosms without herbicide application were treated in the laboratory with two rates of indaziflam (75 and 150 g ai ha^-1) to determine the immediate effect on microbial activity. No significant effect of herbicide treatment on soil respiration and microbial biomass was detected. The results showed a slight to moderate decrease in microbial diversity (7% in 2015 and 44% in 2016). However, decreased β-glucosaminidase activity with herbicide treatment was observed in soils from the mesocosms (33%) and soils treated with indaziflam in the laboratory (45%). The mineral N pool was generally dominated by ammonium after indaziflam application, which was consistent with the drastic decrease (75%) in nitrification activity measured in the laboratory experiment. The results of this study indicate that indaziflam, even when applied at higher than recommended rates, has limited effects on soil microbial activity, but may affect N cycling processes.     

Effect of composting on extractability and relative availability of heavy metals present in Calcutta municipal solid waste

How composting affects heavy metal content is largely unknown. Accordingly, we investigate the total content of six heavy metals, Cd/Zn ratio and the Zn-equiv, the relative availability and fractionation study to assess the suitability of compost derived out of those for environmental concerns. During composting, total metal content increased but their RA decreased. As a result of composting bioavailable form of metals also decreased. High significant correlations between different forms of heavy metals content and degree of humification were found for all the elements. Composting increases humic acid content than fulvic acid. This transformation is mainly responsible to serve as binding agent for metal thereby moderating the rapid metal mobilization.     

Effect of a novel chemical mixture on senescence processes and plant--fungus interaction in Solanaceae plants

The effects of exogenous application of a chemical mixture consisting of adipic acid monoethyl ester, furfurylamine, and 1,2,3,4-tetra-O-acetyl-beta-D-glucopyranose (FGA) on various metabolic pathways and the plant-fungus interaction have been studied in Solanaceae plants. Tomato and pepper plants were sprayed with the FGA mixture, and different biochemical parameters such as gas exchange, chlorophyll concentration, protein, cell wall sugar and phenolics contents, and peroxidase and phenylalanine ammonia lyase (PAL) activities were measured. FGA-treated plants showed, in general, an increase in cell wall sugar content and decreases in the chlorophyll degrading rate and the peroxidase activity. These results suggest that FGA (a possible synthetic regulator) could act as a retardant--antisenescence agent in Solanaceae plants. The FGA mixture increased the PAL activity and promoted an overall rise in the concentration of flavonoids and phenolic compounds. Therefore, FGA induced the synthesis of compounds that could give protection to plants against pathogens or insects. To further verify this putative protection, several fungi were inoculated in intact plants. Exogenous FGA applications on intact plants delayed fungus-provoked lesion development. In addition, data also showed that applications of 1,2,3,4-tetra-O-acetyl-beta-D-glucopyranose inhibited fungal growth in vitro. These results confirm that FGA can activate protective mechanisms in plants upon contact with invaders such as fungi.