ABSTRACT
The aim of this study was the discrimination and optimization of irradiation effect under physical and mechanical experiments on garlic. The samples were irradiated with 0, 75, and 150 Gy doses and stored at 4 and 18°C for 5 months. Physical, mechanical, and color properties were measured in the period of storage. Based on the results, all irradiated garlic samples had less quality variation than control samples. Response surface methodology (RSM) optimized dose, storage time, and temperature of the stored garlic which was 75 Gy, 2 months, and 17°C, respectively. In addition, after finding the optimal dose, time, and temperature, the most effective factor as weight loss was obtained and the data were classified by the principal component analysis (PCA) approach. The results showed that the PCA method had a high ability to classify and separate the data obtained from measuring the physicochemical properties of garlic and cover 99% variance of data. Moreover, partial least square (PLS) was applied for predicting weight loss data with R2 0.9999. As well, a mechanical test was investigated for finding the best situation and duration of storage condition. Finally, irradiation prevented the destruction of garlic and saved garlic in the best quality as compared with control or nonirradiated samples. After all this, it can be decided to keep garlic in warehouses and transfer this product with minimum damage.
ABSTRACT
Infectious plant diseases are caused by pathogenic microorganisms, such as fungi, oomycetes, bacteria, viruses, phytoplasma, and nematodes. Plant diseases have a significant effect on the plant quality and yield and they can destroy the entire plant if they are not controlled in time. To minimize disease-related losses, it is essential to identify and control pathogens in the early stages. Plant disease control is thus a fundamental challenge both for global food security and sustainable agriculture. Conventional methods for plant diseases control have given place to electronic control (E-monitoring) due to their lack of portability, being time consuming, need for a specialized user, etc. E-monitoring using electronic nose (e-nose), biosensors, wearable sensors, and 'electronic eyes' has attracted increasing attention in recent years. Detection, identification, and quantification of pathogens based on electronic sensors (E-sensors) are both convenient and practical and may be used in combination with conventional methods. This paper discusses recent advances made in E-sensors as component parts in combination with wearable sensors, in electronic sensing systems to control and detect viruses, bacteria, pathogens and fungi. In addition, future challenges using sensors to manage plant diseases are investigated.
Subject(s)
Biosensing Techniques , Viruses , Fungi , Plant Diseases , PlantsABSTRACT
ABSTRACT: This study dealt with the fabrication of an impedimetric biosensor based on nanomaterial modified with pencil graphite electrode for the detection of tetracycline (TET) in milk samples. For response of the impedimetric aptasensor to be improved, the influence of different parameters (immobilization time of reduced grapheme oxide, time of aptamer, and TET binding, and concentration of aptamer) was optimized. In optimum conditions, the aptasensor provided a concentration range within 1 × 10-16 - 1 × 10-6 M and with a limit of detection of 3 × 10-17 M TET. The proposed impedimetric aptasensor was then used in milk samples analysis, and the acceptable recovery was achieved ranging from 92.8 to 102.1%. According to this study, the combination of an aptamer and electrochemical impedance spectroscopy is a promising method for detection of TET in milk samples with high reproducibility and stability.
ABSTRACT
The authors describe an impedimetric aptasensor for Penicillin G (PEN) which is an important antibiotic. The method is based on the use of a pencil graphite electrode (PGE) modified with reduced graphene oxide (RGO) and gold nanoparticles (GNPs) for ultrasensitive detection of PEN. The morphology of a bare PGE, RGO/PGE, and GNP/RGO/PGE, and the functional groups on graphene oxide (GO) and RGO were studied using scanning electron microscopy and Fourier transform infrared spectroscopy. Electrochemical impedance spectroscopy was used for detection of PEN by measuring the charge transfer resistance (Rct). Also, cyclic voltammetry was recorded at potential range of 0.30 to +0.70 V for PGE treatment. This aptamer-based assay has a wide linear range that extends from 1.0 fM to 10 µM, and a limit of detection as low as 0.8 fM. The method was applied to the determination of PEN in spiked milk from cow, sheep, goat and water buffalo. Recoveries ranged from 92% to 104%. The assay is fast, ultrasensitive, high reproducible, and selective over antibiotics such as streptomycin, tetracycline, and sulfadiazine. Graphical abstract Schematic presentation of an impedimetric aptasensor for Penicillin G antibiotic using a pencil graphite electrode (PGE) modified with reduced graphene oxide (RGO) and gold nanoparticles (GNPs). This aptamer based assay has limit of detection as low as 0.8 fM.
