氮、磷、钾肥对卡因菠萝产量和品质的影响

运用3414试验设计,在大田试验条件下研究氮、 磷、 钾肥不同配比对卡因菠萝产量和品质的影响,提出适宜的肥料用量。结果表明:施用氮（N）、 磷（P2O5）、 钾肥（K2O）卡因菠萝分别增产15.5、 4.8和12.6 t/hm2,增产率为16.8%、 4.5%和13.1%,增加纯收入34800、 11000和27600 Yuan/hm2,农学效率分别为39.3、 42.3和29.6 kg/kg; 施肥增产、 增收效果以及对产量的贡献率均表现为N＞K2O＞P2O5, 肥料农学效率则表现为P2O5＞N＞K2O。在 P2（100 kg/hm2）K2（500 kg/hm2）基础上,施氮降低果实中维生素C和可滴定酸含量,增加了可溶性糖含量,而在N2（400 kg/hm2）P2（100 kg/hm2）基础上,施钾增加果实中维生素C、 可滴定酸和可溶性糖含量,施用磷肥对果实品质影响不大。对卡因菠萝产量效应函数进行频率分析法寻优得出,卡因菠萝目标产量超过105 t/hm2, 95%置信区间的优化施肥量为氮（N）281.27~436.48 kg/hm2、 磷（P2O5）64.03~121.69 kg/hm2、 钾（K2O）428.59~628.55 kg/hm2,N、 P2O5、 K2O的最优施肥量配比为1∶0.15~0.43∶0.982.23。研究结论可为果农从事卡因菠萝栽培提供施肥参考。     

Monitoring residues of carbendazim (applied as benomyl) and thiabendazole in Wellspur apples

Residues of benomyl (determined as carbendazim, widely accepted as MBC) and of thiabendazole in Wellspur apples were monitored after the apples were treated postharvest by immersion in a bath with each of the fungicides separately and stored under refrigeration. Whole fruit and pulp analyses were conducted over the period beginning 1 day after treatment and lasting up to 200 days afterwards. Under the conditions described, both benomyl (expressed as parts per million of carbendazim) and thiabendazole were found in the fruits in the following average amounts: 0.44 +/- 0.03 and 0.11 +/- 0.03 ppm benomyl (as carbendazim) in whole fruit and in pulp, respectively; 0.98 +/- 0.10 and 0.39 +/- 0.10 ppm thiabendazole in whole fruit and in pulp, respectively.     

Quince (Cydonia oblonga Miller) fruit (pulp, peel, and seed) and Jam: antioxidant activity

To study the antioxidant activity of quince fruit (pulp, peel, and seed) and jam, methanolic extracts were prepared. Each extract was fractionated into a phenolic fraction and an organic acid fraction and was analyzed by high-performance liquid chromatography (HPLC)/diode array detection and HPLC/UV, respectively. Antiradical activities of the extracts and fractions were evaluated by a microassay using 1,1'-diphenyl-2-picrylhydrazyl. The phenolic fraction always exhibited a stronger antioxidant activity than the whole methanolic extract. Organic acid extracts were always the weakest in terms of antiradical activity, which seems to indicate that the phenolic fraction gives a higher contribution for the antioxidant potential of quince fruit and jam. The evaluation of the antioxidant activity of methanolic extracts showed that peel extract was the one presenting the highest antioxidant capacity. The IC50 values of quince pulp, peel, and jam extracts were correlated with the caffeoylquinic acids total content. Among the phenolic fractions, the seed extract was the one that exhibited the strongest antioxidant activity. The IC50 values of quince pulp, peel, and jam phenolic extracts were strongly correlated with caffeoylquinic acids and phenolics total contents. For organic acid fractions, the peel extract was the one that had the strongest antiradical activity. The IC50 values of quince pulp, peel, and jam organic acid fractions were correlated with the ascorbic acid and citric acid contents.     

Quantitative determination of diuron in ground and surface water by time-resolved fluoroimmunoassay: seasonal variations of diuron, carbofuran, and paraquat in an agricultural area

The aim of this research is to develop an ultrasensitive time-resolved fluorescence immunoassay (TR-FIA) for herbicide diuron in water samples. This method appears to be a promising approach, instead of conventional analytical techniques, in the screening procedure of organic pollutants because it is simple, rapid, and specific, and it does not require sample preconcentration or cleanup. Lanthanide chelate used as label allows to achieve sensitivity even 10 times higher than most of the other techniques. It has been applied to monitoring diuron contamination in specimens collected along a year in an agricultural area. The water specimens were collected monthly from lake, well, and irrigation ditch in the agricultural area south of Milan. Assay was performed using diuron-specific polyclonal antibody raised in sheep; as fluorescent marker, we used rabbit antisheep IgG conjugated with a chelating molecule complexed with Eu3+. The compound 4-(3-(3,4-dichloro-phenyl)-1-methyl-ureido)-butyric acid (CPD) was synthesized and conjugated with bovine serum albumin (BSA) to prepare a solid phase. Sensitivity achieved was 20 ng L-1 below the European Community limits. Paraquat (PQ) and carbofuran (CF) presence in the same samples has been also evaluated in a similar way, using immunoassays with time-resolved revelation systems. Diuron concentration shows a peak coinciding with a peak of carbofuran during summer periods. The peak of diuron was 65 pg/mL in June and 180 pg/mL in September in ditch and lake water samples, respectively; carbofuran concentration was higher than diuron in all samples: a carbofuran peak was revealed in September and October resulting in 87 ng/mL. Herbicide paraquat was not detectable in any assayed sample.     

Phenolic profile of quince fruit (Cydonia oblonga Miller) (pulp and peel)

Qualitative and quantitative analyses of phenolic compounds were carried out on quince fruit samples from seven different geographical origins in Portugal. For each origin, both pulp and peel were analyzed by reversed-phase HPLC-DAD and HPLC-DAD/MS.The results revealed differences between the phenolic profiles of pulps and peels in all studied cases. The pulps contained mainly caffeoylquinic acids (3-, 4-, and 5-O-caffeoylquinic acids and 3,5-dicaffeoylquinic acid) and one quercetin glycoside, rutin (in low amount). The peels presented the same caffeoylquinic acids and several flavonol glycosides: quercetin 3-galactoside, kaempferol 3-glucoside, kaempferol 3-rutinoside, and several unidentified compounds (probably kaempferol glycoside and quercetin and kaempferol glycosides acylated with p-coumaric acid). The highest content of phenolics was found in peels.     

Levels of 3,3',4,4'-tetrachloroazobenzene in diuron and linuron herbicide formulations

Levels of 3,3',4,4'-tetrachloroazobenzene (TCAB) were determined by capillary gas chromatography (GC) with electron-capture detection (ECD) in 25 samples of diuron and linuron formulations obtained from the Canadian market. Acidic aqueous methanol was used to retain urea herbicide and the neutral TCAB was allowed to partition into hexane. Silica gel was used for cleanup of the hexane extract, followed by GC/ECD determination. Recovery data obtained at 4 different spiking levels (i.e., 0.3, 0.1, 1.0, and 5.0 ppm) in linuron averaged 93, 86, 85, and 97%, respectively. For diuron, spiking was done at 0.5, 1.0, and 5.0 ppm levels and the corresponding average percent recoveries were 95, 101, and 104. The TCAB contamination level observed in diuron on a 100% active ingredient basis ranged from 0.15 to 3.38 ppm, whereas in linuron, it varied from 0.91 to 10.28 ppm.     

Characterization of sinapyl derivatives in pineapple (Ananas comosus [L.] Merill) juice.

Three previously unidentified phenolic compounds were found in pineapple (Ananas comosus [L.] Merill) juice in substantial concentrations and were isolated by semipreparative reverse phase HPLC. The structures were elucidated from UV spectra, acid hydrolysis, and subsequent amino acid analysis, mass spectrometry, and two-dimensional NMR spectroscopy. The compounds are identified as S-sinapyl-L-cysteine, N-L-gamma-glutamyl-S-sinapyl-L-cysteine, and S-sinapylglutathione.     

Homogeneous preparation of cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB) from sugarcane bagasse cellulose in ionic liquid

Cellulose acetate butyrate (CAB) and cellulose acetate propionate (CAP) were prepared homogeneously in a 1-allyl-3-methylimidazolium chloride (AmimCl) ionic liquid system from sugarcane bagasse (SB). The reaction temperature, reaction time, and molar ratio of butyric (propionic) anhydride/anhydroglucose units in the cellulose affect the butyryl (B) or propionyl (P) content of CAB or CAP samples. The (13)C NMR data revealed the distribution of the substituents of CAB and CAP. The thermal stability of sugar cane bagasse cellulose was found by thermogravimetric analysis to have decreased after chemical modification. After reaction, the ionic liquid was effectively recycled and reused. This study provides a new way for high-value-added utilization of SB and realizing the objective of turning waste into wealth.     

New method for ethephon ((2-chloroethyl)phosphonic acid) residue analysis,and detection of residual levels in the fruit and vegetables of Western Japan

A new method for the detection and quantification of ethephon residues in fruit and vegetables was developed. The present study indicates that fruit and vegetables require a rapid and simple cleanup step before using gas chromatograph/mass spectrometry. The recovery and precision of the new method were evaluated by spiking the fruit and vegetable samples with 0.01-0.1 microg/g of ethephon. The amount of ethephon residue can be determined with good accuracy (recovery, 78.6-109%; coefficient variation, 2.65-6.41%), and the detection limit, defined as the amount of ethephon equivalent to three standard deviations (SD) of the noise level in observations at the baseline level of the selected ion (m/z 110), was 4 pg. The determination limit, defined as the equivalent to 8 SD of the noise level, was 11 pg. The working range was between 10 and 1000 ng/mL, and the correlation coefficient was 0.999 in the five experiments. Ethephon residues were determined between <2 and 97 ng/g in commercial pineapples from Western Japan.     

Influence of methyl isocyanate on the growth,ATP levels,and nitrogen fixation of Azotobacter chroococcum

Summary Growth, ATP levels, and N₂-fixing activity of Azotobacter chroococcum culture exposed to 500 g ml^-1 of methyl isocyanate were investigated. In methyl isocyanate-exposed cells, the lag phase was extended up to 16 h but the control cells started to multiply immediately. ATP levels and N₂-fixing activity as determined by acetylene reduction assay were markedly reduced in the treated cells.     

Free amino acid composition of quince (Cydonia oblonga Miller) fruit (pulp and peel) and jam

Twenty-one free amino acids present in several samples of quince fruit (pulp and peel) and quince jam (homemade and industrially manufactured) were analyzed by GC/FID. The analyses showed some differences between quince pulps and peels. Generally, the highest content in total free amino acids and in glycine was found in peels. As a general rule, the three major free amino acids detected in pulps were aspartic acid, asparagine, and hydroxyproline. For quince peels, usually, the three most abundant amino acids were glycine, aspartic acid, and asparagine. Similarly, for quince jams the most important free amino acids were aspartic acid, asparagine, and glycine or hydroxyproline. This study suggests that the free amino acid analysis can be useful for the evaluation of quince jam authenticity. It seems that glycine percentage can be used for the detection of quince peel addition while high alanine content can be related to pear addition.     

Evaluation of the sorption process for imidacloprid and diuron in eight agricultural soils from southern Europe using various kinetic models

Kinetic studies are of great concern for understanding the processes and parameters involved in the sorption of pollutants by soils. Sorption kinetics of imidacloprid and diuron in eight soils of different characteristics, with very low organic carbon content were investigated. Pseudosecond-order kinetic reactions closely correlate with the experimental kinetic (R(2) > 0.98) in all soils. The sorbed amount of diuron was higher than that for imidacloprid. The low OC content of these soils correlated neither with the sorbed amount nor with the kinetic parameters for both pesticides. Imidacloprid sorption was correlated with silt and sand content and cation exchange capacity (CEC); meanwhile for diuron, no correlation was found. Thus, sorption kinetics take place throughout different mechanisms related mainly to the chemical character of the pesticides. Sorption kinetic parameters determined using three of the four models selected (pseudosecond-order kinetic reactions, Elovich equation, and Weber-Morris models) have been shown to be worthy to distinguish the process controlling the sorption kinetic of both pesticides.     

Chemical,Physicochemical, and Nutritional Evaluation of Plantago (Plantago ovata Forsk)

Plantago ovata F. are small tan‐colored seeds with ≈30% weight husk. Plantago's husk high content of soluble fiber makes it a good lubricant of the intestinal track with demonstrated effects in lowering plasma cholesterol levels in humans and experimental animals. Plantago seeds grown in Northern Mexico were analyzed for proximate composition, combustion heat, soluble and insoluble dietary fiber, fatty acids, amino acids, and protein fractionation. In vitro digestibility and digestibility of dry matter, apparent and true digestibility, and net protein ratio (in vivo) were also analyzed. Plantago seeds had 17.4% protein, 6.7% fat, 24.6% total dietary fiber, 19.6% insoluble fiber, 5.0% soluble fiber, and a combustion heat of 4.75 kcal/g. Osborne fractionation (based on solubility) yielded albumin 35.8%, globulin 23.9%, and prolamin 11.7%. The oil from plantago seeds had a high percentage of linoleic acid (40.6%) and oleic acid (39.1%) and a minor proportion of linolenic acid (6.9%). In vitro protein digestibility of the plantago seed was 77.5%, suggesting a highly digestible protein. Lysine content was 6.82 g/100 g of protein, higher than wheat and oats (2.46 and 4.20 g/100 g of protein, respectively). Rat bioassays showed values of 89.6% digestibility of dry matter, 86.0% apparent digestibility, 88.1% true digestibility, and 4.40 net protein ratio corrected (NPRc). The importance of these findings is that plantago whole grain shows favorable nutritional quality when compared with cereals and legumes.     

Specific natural isotope profile studied by isotope ratio mass spectrometry (SNIP-IRMS): (13)C/(12)C ratios of fructose, glucose, and sucrose for improved detection of sugar addition to pineapple juices and concentrates

The delta(13)C values of fructose, glucose, and sucrose have been determined in authentic pineapple juices. The sugar fraction is separated from the organic acids by an anionic exchange process. Then the individual components (fructose, glucose, and sucrose) are isolated on a preparative HPLC device using a NH(2)-type column. It is demonstrated that no significant isotope fractionation occurs when close to 100% of material is recovered and when the hydrolysis of sucrose is avoided. The control of the recovery rates and of the sucrose hydrolysis rate after purification is recommended for a reliable interpretation of the results. Correlations between the delta(13)C values of fructose (delta(13)Cf), glucose (delta(13)Cg), and sucrose (delta(13)Csu) can be characterized by systematic differences between these values. For the set of measurements on authentic pineapple juices and concentrates, the mean and the standard deviation of the differences are delta(13)Cf - delta(13)Cg = -0.6 +/- 0.6 per thousand, delta(13)Cf - delta(13)Csu = -1.3 +/- 0. 6 per thousand, and delta(13)Cf - delta(13)Csu = -0.7 +/- 0.5 per thousand. The determinations of the (13)C content of fructose, glucose, and sucrose enable a refinement of the detection of added sugars in fruit juices, re-enforcing the SNIP-IRMS method.     

Enantiomeric synthesis of (S)-2-methylbutanoic acid methyl ester, apple flavor, using lipases in organic solvent

Enantiomeric selective synthesis of (S)-2-methylbutanoic acid methyl ester, which is known as a major apple and strawberry flavor, was performed from racemic 2-methylbutanoic acid using lipases in organic solvent. Among 20 lipases, lipase IM 20 (immobilized lipase of Rhizomucor miehei), lipase AP (Aspergillus niger), and lipase FAP-15 (Aspergillus javanicus) exhibited higher enzymatic activities and enantioselectivities and were selected for the synthesis of (S)-2-methylbutanoic acid methyl ester. Using these enzymes, the reaction conditions such as temperature and lyophilizing pH were optimized, and kinetic parameters were determined. All of the reactions were performed in isooctane, which was identified as the best reaction media for nonaqueous systems. At 20 degrees C maximum enantiomeric excess was observed, while synthetic activity increased as the temperature increased. Only lipases lyophilized at pH 5.5, 6. 0, 6.5, and 7.0 showed synthetic activity. In this pH range, enantioselectivities were not influenced by the lyophilizing pH. The K(M,S) and K(M,R) values for ester synthetic activity of lipase were 1120 and 1240 mM, respectively. Enzyme activity was inhibited by (S)-2-methylbutanoic amide, and its K(i) was calculated as 84 mM. (S)-2-Methylbutanoic amide acted as a competitive inhibitor.     

Antimicrobial activity of Tunisian quince (Cydonia oblonga Miller) pulp and peel polyphenolic extracts

Quince (Cydonia oblonga Miller) fruit aqueous acetone extracts were evaluated. High-performance liquid chromatography-diode array detection and electrospray ionization-mass spectrometry were used for the identification and quantification of the phenolic compounds. The total phenolic content of the pulp and peel parts ranged from 37 to 47 and 105 to 157 mg/100 g of fresh weight, respectively. Chlorogenic acid (5-O-caffeoylquinic acid) was the most abundant phenolic compound in the pulp (37%), whereas rutin (quercetin 3-O-rutinoside) was the main one in the peel (36%). The radical scavenging potential of the extracts was determined and compared with that of synthetic antioxidants. The stronger properties corresponded to those obtained from peel material with a 70-80% inhibitory effect on DPPH radicals. The antimicrobial activity of the extracts against different microorganism strains was also investigated. Quince peel extract was the most active for inhibiting bacteria growth with minimum inhibitory and bactericide concentrations in the range of 102-5 x 103 microg polyphenol/mL. It seems that chlorogenic acid acts in synergism with other components of the extracts to exhibit their total antimicrobial activities.