Bioactive metabolite profiles and quality of Rosa rugosa during its growing and flower-drying process.

Rosa rugosa is extensively cultivated in China for its remarkable fragrance and flavor, however, the metabolic changes in roses during growth and drying remain unclear. Our results revealed significant variations in phenol and flavonoid contents and antioxidant capacity in roses (Rosa rugosa f. plena (Regel) Byhouwer) under different conditions. Phenol contents were positively correlated with antioxidant capacity, with phytochemicals being most prominent in unfolded petals. The highest antioxidant capacity and phenol and flavonoid contents were observed in April. Considering their greater consumption value, whole flowers were more suitable than petals alone. Furthermore, considerable sensory and nutritional differences were observed in dried roses. Different drying methods increased their total phenol content of roses by 4.2-5.4 times and the antioxidant capacity by 2.9 times. Metabolomics revealed the altered contents of flavonoids, anthocyanins, lipids, amino acids, and saccharides. This study provides baseline data for the potential of roses as a natural source of antioxidants in the food and pharmaceutical industries.

Residue behaviors, processing factors and transfer rates of pesticides and metabolites in rose from cultivation to consumption.

The presence of pesticide residues in rose makes it necessary to pay special attention to the proper cultivation to consumption. In this study, the inherent regularity of residue behaviors, processing factors and transfer rates of pesticides and potential metabolites during rose planting, drying and brewing was researched. The half-lives in the bud, corolla and leaf were 0.5-2.9, 0.3-1.7 and 2.6-25.9 d, respectively. Residues were more distributed in leaf, followed by corolla, bud and root. Systemic pesticides could appear in the root 1 day after application, and non-systemic pesticides were not detected in the root. The effect of sun and oven drying (80 °C) was more significant in promoting the degradation of cyazofamid, bifenazate, thiamethoxam and imidacloprid. The processing factors (PFs) of other pesticides were > 1. Our results showed that the transfer rate of residues during brewing was negatively correlated exponentially with Log Kow and positively logarithmically correlated with melting point and water solubility. The transfer rate of residues and antioxidant capacity in infusion were significantly affected by different brewing conditions.

Residue distribution and risk assessment of bifenazate and its metabolite in garlic plant.

The dissipation, conversion and risk assessment of bifenazate and bifenazate-diazene in garlic plant were studied by a modified QuEChERS method coupled with UHPLC-MS/MS for the first time. Bifenazate dissipated rapidly in garlic chive and serpent garlic with the half-lives of 3.0-3.9 days and 6.1-6.9 days, respectively. Bifenazate residue on garlic (<0.01 mg/kg) was significantly lower than the other two matrices in the whole growing period, which meant residues in the above-ground part were not transferred to the garlic. Furthermore, garlic chive had higher residues than serpent garlic due to the differences in morphological characteristics. Bifenazate-diazene was easier to convert to bifenazate, with the conversion rates of 93%, 16% and 32% in garlic, serpent garlic and garlic chive extracts, respectively. Additionally, the dietary intake risk for bifenazate was acceptable with RQchronic < 100% according to the international and national assessments.

Determination, residue analysis, dietary risk assessment, and processing of flupyradifurone and its metabolites in pepper under field conditions using LC-MS/MS.

An effective method based on LC-MS/MS was established to determine the concentrations of flupyradifurone, difluoroacetic acid, and 6-chloronicotinic acid in pepper. On the basis of this method, the dissipation, processing factor, and dietary risk of flupyradifurone in pepper were investigated. The results show that the half-life of flupyradifurone in peppers was 2.6-3.8 days. The terminal residual concentration of flupyradifurone in the supervised trials was not higher than the maximum residue limit (MRL) for pepper in the Codex Alimentarius Commission (CAC) (0.9 mg kg-1 ) with the highest residual values of 0.53 mg kg-1 . The national estimated daily intake of flupyradifurone was 0.00094 mg kg-1 , based on the dietary structure of Chinese consumers and the terminal residues under field conditions. The risk quotient for flupyradifurone was 0.012, which was significantly < 1. The processing factor of flupyradifurone in dried pepper was 10.9-14.2, which indicated that drying increased the residual amounts of flupyradifurone in dried pepper, but the residual concentration was still lower than its MRL of 9 mg kg-1 established by CAC.

Effect of storage states on stability of three organophosphorus insecticide residues on cowpea samples.

BACKGROUND: The stability of pesticide residues in stored samples is very important to ensure the quality of data about the residues. The evaluation of pesticide residues in food and environment samples is an important means to ensure food quality and protect consumers against potential dietary risks. Improper storage of pesticide residue samples may result in loss of pesticide and unreliable data, which could affect safety assessments. RESULTS: The influences of storage conditions, including temperature (-20 °C, 4 °C, and ambient temperature) and sample state (homogenized state and coarsely chopped state) on the storage stability of dichlorvos, malathion, and diazinon on cowpea were studied. Dichlorvos and malathion were more stable in an homogenized state than in a coarsely chopped state. At 4 °C, the residual dichlorvos in the coarsely chopped state and the homogenized state, respectively, was 12% and 69%; the residual malathion was 26% and 92%, respectively. Dichlorvos suffered a large loss of 89% and 59% for coarsely chopped and homogenized cowpea, even at -20 °C. It was obvious that the stability of dichlorvos and malathion were more affected by storage state than diazinon. The stability of diazinon was significantly affected by temperature. The effect of storage state and temperature on stability is likely to be correlated with enzymes in the matrix, such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). CONCLUSION: The optimal stable storage conditions for three organophosphorus insecticides residues on cowpea were in the homogenized state and under a lower temperature. © 2021 Society of Chemical Industry.

The stability of four organophosphorus insecticides in stored cucumber samples is affected by additives.

The influence of some additives, including metal ions, antioxidants, enzyme inhibitors and organic solvents, on the storage stability of four organophosphorus pesticides in cucumber samples were investigated. It was found that metal ions, including Al3+, Fe3+, and Co2+, increased the stability of dichlorvos, malathion, and chlorpyrifos. Conversely, Al3+, Fe3+, Fe2+, and Co2+ caused catalytic degradation of diazinon. With the addition of organic solvents (CH2Cl2, CHCl3, CCl4, CH3OH and CH3COCH3), remaining of diazinon residues was higher (16-54%) after storage for seven days. CCl4 was associated with the highest retention of malathion, diazinon, and chlorpyrifos (33%, 48% and 44%, respectively) in samples. SDS also stabilized the pesticides since residues were, again, higher (13-38%) after seven days storage. Furthermore, addition of Al3+ and Fe3+ decreased peroxidase (POD) activity and inhibited degradation of dichlorvos and malathion. After 14 days, lyophilization increased the pesticide residues remaining by 36%, 29%, and 58% for diazinon, malathion and chlorpyrifos, respectively. Overall, the stability of these pesticides during storage is impacted by water content and addition of exogenous substances. This could ensure higher quality of pesticide residue data in samples.

Residue behavior and removal of iprodione in garlic, green garlic, and garlic shoot.

BACKGROUND: Iprodione is considered to be an endocrine-disturbing pesticide, which could harm consumers. The garlic crop has three edible parts: the garlic, the green garlic, and the garlic shoot, which correspond to different stages of its growth. In this study, iprodione residue dissipation and distribution in these three edible parts were investigated, and dietary risk was evaluated. RESULTS: Iprodione residues were present in these samples in the following order: green garlic > garlic shoot > > garlic. The dissipation of iprodione in green garlic was slow with a half-life of 5.82-19.25 days. A very high RQchronic value of 207.35-407.30% suggested that the residual iprodione in green garlic had an unacceptable level of risk. Iprodione residue was significantly eliminated (59-90%) by an alkaline solution. The order for removing iprodione by soaking was the alkaline solutions (0.5% and 2% NaHCO3 ) > the acidic solutions (5% and 10% of vinegar) ≈ the neutral solutions (the 1% and 2% of table salt) > tap water. Processing factors (PFs) were <1, indicating that processing could decrease the iprodione residue level. CONCLUSION: This work could contribute to establishing maximum residue limits (MRLs) for iprodione in garlic, green garlic, and garlic shoots, and could provide guidance on the safe and appropriate use of iprodione in the garlic crop. © 2020 Society of Chemical Industry.

Improved analysis of propamocarb and cymoxanil for the investigation of residue behavior in two vegetables with different cultivation conditions.

BACKGROUND: A modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method was developed for the simultaneous determination of highly water-soluble propamocarb and hydrophobic cymoxanil in potato tuber and tomato fruit. Residue behaviors of the fungicides in open field or greenhouse were investigated for the safety evaluation of these two pesticides, and the effects of cultivation conditions, fungicide exposure and fruit size of tomato on residue level are discussed. RESULTS: Vegetable samples were extracted with ammonia-acetonitrile, further purified with multiwall carbon nanotubes and analyzed using high-performance liquid chromatography tandem mass spectrometry. The method was validated with fortified samples at different concentration levels (0.05-2.0 mg kg-1 ). Average recoveries ranged from 84 to 111% with relative standard deviations between 0.3 and 5.5%. Limits of quantification (LOQs) were set at the lowest spiking level of 0.05 mg kg-1 . In tomato and cherry tomato, initial residue level of cymoxanil was below LOQ at recommended good agricultural practices. Propamocarb residues were affected by the cultivation conditions, with highest levels of 0.52 and 0.72 mg kg-1 in open field and greenhouse, respectively. In addition, residues of propamocarb in cherry tomatoes were found to be present at 1.25 mg kg-1 . CONCLUSIONS: The field trial results showed that propamocarb and cymoxanil residues in potato tubers were below LOQ due to the tubers not being exposed to sprayed pesticides. The unexpected high residue levels in cherry tomato seem to indicate that cherry tomato with small size presents certain accumulative effects of propamocarb. © 2020 Society of Chemical Industry.

Meptyldinocap and azoxystrobin residue behaviors in different ecosystems under open field conditions and distribution on processed cucumber.

BACKGROUND: Several diseases and insects may cause damage to the normal growth of cucumber. Azoxystrobin and meptyldinocap, because of their novel mode of action, are effective against pathogens that have developed reduced sensitivity to other fungicides. Azoxystrobin is persistent in various crops and environments. However, there is a lack of research on the dissipation of these two pesticides, especially meptyldinocap. RESULTS: Analytes could be quantified with decent recoveries of 90-101%, with relative standard deviations (RSDs) of 3.0-10.1%. The terminal residues of meptyldinocap and azoxystrobin in cucumber were all < limit of quantification (LOQ) (0.02 and 0.05 mg kg-1 ). The half-lives of meptyldinocap and azoxystrobin were 0.8-1.1 and 1.2-2.8 days, respectively. The processing factors (PFs) for washing were all < 1, but the removal rate for washing was < 29.0%. Peeling had a significant effect on the removal of pesticide. The largest residue reductions were noticed through the pickling process, but special care should be taken regarding residues in the pickling solution as pesticides could transfer to them from cucumber. A more interesting finding was that the degradation of two pesticides was accelerated by the addition of calcium oxide. CONCLUSION: Pesticide residues on cucumber decreased after these processes. These results enable the health-risks from dietary exposures to pesticide residues to be characterized. They enable maximum residue limits (MRLs) to be established for pesticide residues in food products. They also assist the optimization of food processing with regard to pesticide residue dissipation. © 2019 Society of Chemical Industry.

The effects and mechanism of using ultrasonic dishwasher to remove five pesticides from rape and grape.

In this study, the ultrasonic dishwasher was used to remove five pesticides known to be frequently used on rape and grape. As compared with normal water washing, washing with the ultrasonic dishwasher was demonstrated to be more effective for pesticides removal, achieving removal rates between 14.7% and 59.8% on rape, and between 72.1% and 100% on grape. However, there were significant differences in order of the removal rate of five pesticides on rape and grape. From the adsorption experiments and analysis via Freundlich equation, the adsorption index (n, 0.551-1.056 on rape and 0.362-1.478 on grape) and adsorption coefficient (KF, 10-2.47-10-1.65 and 10-3.64-10-1.56 (mg·dm-2)/(mg·L-1)-n on rape and grape) were obtained. Taken together with the observation of the matrix surface by scanning electron microscopy and the evaluation of the physicochemical properties of pesticides, the different pesticides removal may be related to surface structure of the matrix.

Bitter gourd has the highest azoxystrobinon residue after open field application on four cucurbit vegetables.

The goal of this study was to select a representative cucurbit vegetable crop that contained the highest residue levels of the pesticide azoxystrobinon. To do this, we used open field application of azoxystrobinon in four cucurbit crops (cucumber, zucchini, bitter gourd, and loofah) in Beijing, Shandong, and Anhui. Liquid chromatograph-mass spectrometry/mass spectrometry (LC-MS/MS) with selected reaction monitoring was used to determine azoxystrobinon levels in each of the selected cucurbit vegetables. The azoxystrobinon limit of detection was 0.005 mg kg-1 for all samples. Recoveries of azoxystrobinon ranged from 94.2% to 107.1% at spiked levels of 0.005-0.5 mg kg-1. In field trials, the half-life of azoxystrobinon in each of the four cucurbit crops was within the range of 1.4-3.1 d. Based on these results, we recommend that bitter gourd is selected as a representative cucurbit vegetable for future studies of azoxystrobinon. The obtained residual data were also assessed for their dietary risk and results indicated that there is no chronic dietary risk in any of the four, selected cucurbit vegetables. The recommended maximum residue limit (MRL) of azoxystrobinon in this subgroup was 0.2 mg/kg.

Storage stability of organophosphorus pesticide residues in peanut and soya bean extracted solutions.

This study was performed to determine the storage stability of organophosphorus pesticide residues in high oil content commodity matrices, peanut and soya bean. The storage conditions included different types of solvents (ethyl acetate, acetone and hexane) and corresponding extracted matrix solutions, light and temperature. It was found that three pesticides degraded quickly especially in ethyl acetate solvent. They decreased greater than 30% when stored for 3 days at -20°C in ethyl acetate; the results showed that the stability could be improved in the extracted matrix solutions. Light had a slight effect for stability of phorate and fenthion, while it played an important effect for disulfoton with the exception of ethyl acetate as solvent. Even at -20°C, exposure to solvents or extracted matrix solution resulted in 40.67, 96.33 and 35.07% loss of phorate, disulfoton and fenthion. Hence, it could be assumed that these three residues could be more stable at lower temperature, in the dark and in acetone or hexane extracted peanut and soya bean solutions.

Storage stability of three organophosphorus pesticides on cucumber samples for analysis.

The residue sample storage stability of three organophosphorus pesticides, dichlorvos, diazinon, and malathion, under different conditions was investigated. The storage conditions studied included storage time, temperature, and sample form. The addition of extra enzyme to the samples was also studied to investigate its effect on stability. It was found that malathion was more unstable than dichlorvos and diazinon, there was an over 70% loss in 90 days even at -20 °C in coarsely chopped form. The pesticide residues were more stable when the cucumber was in homogenate form than coarsely chopped. Furthermore, the addition of catalase increased the degradation of malathion, where there was more decomposition with increasing levels of catalase. However, there was no obvious relationship between degradation of dichlorvos and diazinon and catalase concentration. Overall, this study revealed factors that can be optimized to increase the storage stability of organophosphorus pesticides, where enzyme was one of the main influencing factors.

Comparison of micellar extraction combined with ionic liquid based vortex-assisted liquid-liquid microextraction and modified quick, easy, cheap, effective, rugged, and safe method for the determination of difenoconazole in cowpea.

Two simple sample pretreatment for the determination of difenoconazole in cowpea was developed including micellar extraction combined with ionic liquid based vortex-assisted liquid-liquid microextraction (ME-IL-VALLME) prior to high performance liquid chromatography (HPLC), and modified quick, easy, cheap, effective, rugged, and safe method (QuEChERS) coupled with HPLC-MS/MS. In ME-IL-VALLME method, the target analyte was extracted by surfactant Tween 20 micellar solution, then the supernatant was diluted with 3mL water to decrease the solubility of micellar solution. Subsequently, the vortex-assisted liquid-liquid microextraction (VALLME) procedure was performed in the diluted extraction solution by using the ionic liquid of 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM]PF6) as the extraction solvent and Tween 20 as an emulsifier to enhance the dispersion of the water-immiscible ionic liquid into the aqueous phase. Parameters that affect the extraction have been investigated in both methods Under the optimum conditions, the limits of quantitation were 0.10 and 0.05mgkg-1, respectively. And good linearity was achieved with the correlation coefficient higher than 0.9941. The relative recoveries ranged from 78.6 to 94.8% and 92.0 to 118.0% with the relative standard deviations (RSD) of 7.9-9.6% and 1.2-3.2%, respectively. Both methods were quick, simple and inexpensive. However, the ME-IL-VALLME method provides higher enrichment factor compared with conventional QuEChERS method. The ME-IL-VALLME method has a strong potential for the determination of difenoconazole in complex vegetable matrices with HPLC.