Mahmood Esna-Ashari

Bio: Mahmood Esna-Ashari is an academic researcher from Bu-Ali Sina University. The author has contributed to research in topics: Postharvest & Titratable acid. The author has an hindex of 13, co-authored 36 publications receiving 472 citations. Previous affiliations of Mahmood Esna-Ashari include University of Salford.

Agrobacterium-mediated genetic transformation of plants: The role of host

Abstract: Agrobacterium-mediated genetic transformation is the most widely used technology to obtain overexpression of recombinant proteins in plants. Molecular events that occur within Agrobacterium during interactions with host plants have been studied extensively, and now we have a reasonable understanding the key factors involved in the regulation of T-DNA nuclear import and genomic integration. By contrast, very little is known about the events that take place in the host cells during genetic transformation by Agrobacterium. Here, we describe the plant-related factors including genotype, genes, proteins, competency of target tissues and phenolic compounds that participate in Agrobacterium-mediated genetic transformation and discuss their possible roles in this process. Because Agrobacterium probably adapts existing cellular processes for its life cycle, identifying the processes in host cells during Agrobacterium infection might contribute to better understanding of basic biological processes as cell communication, intracellular transport and DNA repair and recombination as well as to expanding the host range of Agrobacterium as a genetic engineering tool.

Modeling of moisture diffusivity, activation energy and specific energy consumption of high moisture corn in a fixed and fluidized bed convective dryer

Abstract: Thin layer drying characteristics of high moisture corn under fixed, semi fluidized and fluidized bed conditions with high initial moisture content (66.82% wb) in a laboratory fluidized bed convective dryer was studied at air temperatures of 50, 65, 80 and 95°C. In order to find a suitable drying curve, seven thin layer-drying models were fitted to the experimental data of moisture ratio. Among the applied mathematical models, Midilli et al. model was the best for drying behavior prediction in corn thin layer drying. This model presented high values for correlation coefficient (R2). Fick´s second law was used to compute moisture diffusivity with some simplifications. Computed values of moisture diffusivity varied at the boundary of 4.87 × 10–11 – 2.90 × 10–10 m2 s–1 and 1.02 × 10–10 – 1.29 × 10–9 m2 s–1 during the first and second drying falling-rate, respectively. Values of effective moisture diffusivity for corn were also increased as input air temperature was increased. Value of activation energy varied from a minimum of 18.57 to a maximum of 50.74 kJ mol–1 from 50 to 95°C with drying conditions of fixed to fluidized bed. Specific energy consumption (SEC) for thin-drying of high moisture corn was found to be in the range of 0.33 × 106 – 1.52 × 106 kJ kg–1 from 50 to 95°C with drying condition of fluidized and fixed bed, respectively. Increase in air temperature in each air velocity caused decrease in SEC value. These corn properties would be necessary to design the best dryer system and to determine the best point of drying process.

Antioxidant and antimicrobial activities of Iranian mooseer (Allium hirtifolium Boiss) populations

Abstract: Mooseer or Persian shallot is a bulbous perennial herb belonging to the Alliaceae family. Antioxidant activities of 12 mooseer populations were determined using three assays including DPPH, FRAP, and ABTS. Antioxidant activities differed among all populations with the Sahneh and Nahavand population as the highest and the lowest, respectively. Antimicrobial activity of mooseer extracts were tested against six bacteria including Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae and two fungi including Candida albicans and Saccharomyces cerevisiae by disc diffusion method by determining their minimum inhibitory concentration values with all samples indicating moderate to high antimicrobial activity. For antimicrobial activity, Esfahan population showed the highest inhibitory effect on bacteria and fungi. According to the results of the study, mooseer has potential as a valuable dietary supplement.

Abscisic acid-mediated leaf phenolic compounds, plant growth and yield is strawberry under different salt stress regimes

Abstract: The present research was conducted to evaluate the interaction effects of exogenous abscisic acid (ABA) and salt stress on phenolic compounds, growth and yield of two short day strawberry cvs "Queen Elisa" and "Kurdistan". Plants were subjected to control, gradual salt stress (up to 20 mmol L-1 over 5 weeks) and salinity shock (20 mmol L-1). ABA treatments included: 0 (control), 5, 10, 20 and 40 µmol L-1. The experiment was carried out based on a complete randomized design in factorial experiment. The highest level of ferulic acid was observed by applying 40 µmol L-1 ABA in "Queen Elisa" under salt stress shock but effective increase in caffeic acid and p-coumaric acid was shown at gradual salt stress for both cultivars at the same ABA level. Maximum level of ABA led to the highest gentisic acid and gallic acid at gradual salt stress in "Kurdistan". Methyl gallate and flavonoid content showed a striking increase at the same conditions in "Queen Elisa". The interaction effect of salt stress regimes and ABA resulted in an increase in ellagic acid content for both cultivars. The interaction effect of ABA and salt shock caused higher reduction in root and shoot fresh dry weights and decrease in fruit yield in "Kurdistan". The results of this experiment accounts for the important role of exogenous ABA in the activation of antioxidant defense mechanism, growth and yield maintenance under gradual salt stress in strawberry.

Recent advances in nano-enabled fertilizers and pesticides: a critical review of mechanisms of action

Abstract: The use of nanomaterials in agriculture as nanofertilizers, nanopesticides, or nano-enabled sensors to increase crop yield is gaining increasing interest. Engineered nanomaterials (ENMs) can improve crop productivity by influencing fertilizer nutrient availability in soil and uptake by plants. These materials can suppress crop diseases by directly acting on pathogens through a variety of mechanisms, including the generation of reactive oxygen species (ROS). ENMs may also suppress disease indirectly by improving crop nutrition and enhancing plant defense pathways. Efficient use of ENMs may complement or replace conventional fertilizers and pesticides, subsequently reducing the environmental impact of agricultural practices. This review evaluates the current literature on ENMs used as pesticides and fertilizers, and highlights critical knowledge gaps that must be addressed to ensure sustainable application of nanotechnology in agriculture so as to achieve global food security.

Study the effect of sun, oven and microwave drying on quality of onion slices

Abstract: Sun, oven (50 and 70 °C) and microwave oven (210 and 700 W) drying of onion slices were carried out to monitor the drying kinetics and quality degradation of the product. Page, “Modified Page” and “Midilli and Kucuk” models exhibited high coefficient of determination (R2) values, ranging between 0.994 and 0.999. The calculated effective diffusivity (Deff) values (m2/s) of onion slices for the sun, oven 50 °C and oven 70 °C, microwave 210 W and microwave 700 W drying process were 8.339 × 10−10, 7.468 × 10−10, 1.554 × 10−9, 4.009 × 10−8 and 4.869 × 10−8, respectively. Fresh and dried onion slices had high amounts of K (696.82–16357.55 mg/kg), Ca (69.64–340.03 mg/kg), Na (37.72–1895.43 mg/kg), Mg (3.31–964.77 mg/kg) and P (46.47–3384.07 mg/kg) minerals. The highest mineral values were determined in oven dried samples. Sun (L∗ 58.00 ± 4.83, a∗ 0.27 ± 0.10, b∗ 14.36 ± 2.40) and microwave oven drying (210 W) (L∗ 54.78 ± 7.54, a∗ −0.71 ± 0.09, b∗ 13.17 ± 1.05) revealed better colour values in the dried products. The phenolic contents of microwave oven dried samples (1664.39 ± 134.12 and 1623.59 ± 140.02 for 210 W and 700 W, respectively) were higher than those of the other dried onion slices.

A Review on Thin-Layer Drying-Curve Equations

Abstract: This paper presents a comprehensive review of thin-layer drying-curve models available in the literature and their comparisons for single-layer drying applications from 2003 to 2013. In this regard, a total of 67 models are selected and classified under 28 performance assessment criteria for comparison purposes. These models are then evaluated by considering the following parameters: (1) product type; (2) pretreatment type; (3) drying parameters, such as temperature, air velocity, layer thickness, microwave power levels, amount of solar radiation, vacum pressure, frequency of sound wave, excitation amplitude, relative humidity, bed depth, product shape, pH, salt content, absolute pressure, etc.; and (4) drying method employed. Furthermore, the best models obtained are employed for product drying applications and compared for different drying methods, drying parameters, and dried products.