Ruplal Choudhary

Effects of ultrasonic treatments on the polyphenol and antioxidant content of spinach extracts

The objective was to test ultrasound treatments on spinach leaves during extraction, and conventional extraction was used as a control. The effects of different combinations of the ultrasonic water bath factors tested on phenolic compound yields included frequency (37 and 80 kHz), exposure time (5, 10, 15, 20, 25, and 30 min), temperature (30, 40, and 50°C), and ultrasonic power (30%, 50%, and 70%). The best conditions for extraction yields were ultrasonic frequency of 37 kHz, extraction time of 30 min, reaction temperature of 40°C, and ultrasonic power of 50%. The mean yield (mg/100g), total phenol (mg gallic acid/g DW), flavonoids (mg/g DW), % DPPH free-radical scavenging activity, and % ferric reducing antioxidant power were all high (64.88 ± 21.84, 33.96 ± 11.30, 27.37 ± 11.85, 64.18 ± 16.69 and 70.25 ± 9.68). Treatments were significantly different. The interaction among the ultrasonic parameters was significant. Temperature and power had significant effects on all other dependent variables.

Polydiacetylene nanovesicles as carriers of natural phenylpropanoids for creating antimicrobial food-contact surfaces.

The ultimate goal of this study was developing antimicrobial food-contact materials based on natural phenolic compounds using nanotechnological approaches. Among the methyl-β-cyclodextrin-encapsulated phenolics tested, curcumin showed by far the highest activity toward Escherichia coli with a minimum inhibitory concentration of 0.4 mM. Curcumin was enclosed in liposome-type polydiacetylene/phosholipid nanovesicles supplemented with N-hydroxysuccinimide and glucose. The fluorescence spectrum of the nanovesicles suggested that curcumin was located in their bilayer region. Free-suspended nanovesicles tended to bind to the bacterial surface and demonstrated bactericidal activity toward Gram-negative (E. coli) and vegetative cells of Gram-positive (Bacillus cereus) bacteria reducing their counts from 5 log CFU mL(-1) to an undetectable level within 8 h. The nanovesicles were covalently bound to silanized glass. Incubation of E. coli and B. cereus with nanovesicle-coated glass resulted in a 2.5 log reduction in their counts. After optimization this approach can be used for controlling microbial growth, cross-contamination, and biofilm formation on food-contacting surfaces.

Ultrasound Assisted Extraction of Phenolic Compounds from Peaches and Pumpkins

The ultrasound-assisted extraction (UAE) method was used to optimize the extraction of phenolic compounds from pumpkins and peaches. The response surface methodology (RSM) was used to study the effects of three independent variables each with three treatments. They included extraction temperatures (30, 40 and 50°C), ultrasonic power levels (30, 50 and 70%) and extraction times (10, 20 and 30 min). The optimal conditions for extractions of total phenolics from pumpkins were inferred to be a temperature of 41.45°C, a power of 44.60% and a time of 25.67 min. However, an extraction temperature of 40.99°C, power of 56.01% and time of 25.71 min was optimal for recovery of free radical scavenging activity (measured by 1, 1-diphenyl-2-picrylhydrazyl (DPPH) reduction). The optimal conditions for peach extracts were an extraction temperature of 41.53°C, power of 43.99% and time of 27.86 min for total phenolics. However, an extraction temperature of 41.60°C, power of 44.88% and time of 27.49 min was optimal for free radical scavenging activity (judged by from DPPH reduction). Further, the UAE processes were significantly better than solvent extractions without ultrasound. By electron microscopy it was concluded that ultrasonic processing caused damage in cells for all treated samples (pumpkin, peach). However, the FTIR spectra did not show any significant changes in chemical structures caused by either ultrasonic processing or solvent extraction.

Optimization of Lime Pretreatment of Sweet Sorghum Bagasse for Enzymatic Saccharification

With recent emphasis on development of alternatives to fossil fuels, sincere attempts are being made on finding suitable lignocellulosic feedstocks for biological conversion to fuels and chemicals. Sweet Sorghum is among the most widely adaptable cereal grasses, with high drought resistance, and ability to grow on low quality soils with low inputs. It is a C4 crop with high photosynthetic efficiency and biomass yield. Our research objective is to optimize lime pretreatment of sweet sorghum bagasse for its enzymatic conversion into fermentable sugars for biofuels. Sweet sorghum biomass was ground and passed through a 35 mesh screen. Moisture content of the biomass was approximately 12%. It had 32.3% cellulose, 21.2% hemicelluloses, and 8.3% acid detergent lignin on dry matter basis. Lime pretreatment was provided in atmospheric pressure at 100oC. The lime concentration was varied from 0.05 g/g biomass to 0.2 g/g biomass; reaction time was 1 hour to 3 hours, and liquid loading was varied from 7 to 20 ml lime solution /g biomass sample. Pretreated biomass was hydrolyzed with mixture of two enzymes, Accellerase® 1500 (Cellulase) at 0.24 mL/g of SSB and Accellerase® XC (xylanase) at 0.25 ml/g of SSB, and measured for total reducing sugars by DNS (1,3-dinitrosalicylic acid) reagent.

Determination of Antioxidant Activity in Different Kinds of Plants In Vivo and In Vitro by Using Diverse Technical Methods

The phenolic compounds content and antioxidant activity in plant are very necessary for human health in light of their high active compounds which are very important to protect human body from hard diseases. Therefore, due to evaluated antioxidant activity of various samples (plants), we used 18 methods which were mentioned in 100 articles in different explanations. All of these diverse methods were discussed to demonstrate and show which method is more frequent either in vivo or in vitro. Moreover, there were different kinds of solvents which were used to extract phenolic compounds from plants. So, the results show that a,a-diphenylpicrylhydrazyl (DPPH) was more frequent method to determine of antioxidant activity in vitro, while Lipid Peroxidation (LPO) was more common to evaluate antioxidant activity in vivo. Ultimately, methanol was found to be most common solvent which was used to extract phenolic compounds from plants

Detection of charcoal rot (Macrophomina phaseolina) toxin effects in soybean (Glycine max) seedlings using hyperspectral spectroscopy

Abstract Charcoal rot caused by the fungal pathogen Macrophomina phaseolina is an important disease of soybean and the use of resistant cultivars is recommended to manage the disease. Since symptoms, including leaf wilt, typically occur as soybeans reach maturity, screening varieties for tolerance to charcoal rot can be time-consuming, requiring nearly an entire growing season. In this study, soybean seedlings (V1) were exposed to a culture filtrate of M. phaseolina containing toxin(s) produced by the fungal pathogen. The effect on the seedlings was measured with hyperspectral spectroscopy on leaves. Two spectrometers integrated with a fiber optic light source and a 6.35 mm diameter probe yielding 480–850 nm and 900–2400 nm ranges after preprocessing were used. The spectra of the untreated plants measured at 0 h, 4 h, 8 h, 12 h, and 24 h post-exposure to the fungal extract were nearly indistinguishable. In contrast, the toxin-treated plants had significantly different spectra from the untreated plants at each of the 4 h, 8 h, 12 h, and 24 h measurements. Reflectance increased in the NIR (900–2400 nm) region with extended exposure to the fungal extract. This change was most noticeable in the 1450 nm and 1940 nm wavebands. Across the spectra, the 24 h reflectance was significantly higher than that of 12 h, which was significantly higher than those of 8 h, 4 h, and 0 h. Jeffries-Matusita (JM) distance, quantifying class separability, was used as a feature selection method and the 24 h measurement had the highest JM distance values, which indicated good separability. Based on JM Distance the most sensitive wavebands were in the regions of 1370–2400 nm. A ratio of the reflectance at 0 h to reflectance at the other times for each of the wavebands was calculated. The ratio curves had two noticeable troughs centered on 1450 nm and 1940 nm, with respective ratios of 0.47 and 0.32 for the 24 h measurement. The 1940 nm ratio at 24 h was proposed as a relative measure of charcoal rot susceptibility of soybean varieties. A ratio of 1.0 indicated no susceptibility with lower ratios indicating greater susceptibility to charcoal rot toxin(s). This study has implications in terms of developing tools to screen for soybean varieties tolerant to charcoal rot and potentially for other biotic or abiotic factors that induce foliar wilting.

Nano-inspired systems in food technology and packaging

Creation of food-based nanomaterials for food processing and packaging applications is actually gaining in importance. Indeed, the design of a suitable food carrier system controls the encapsulation efficiency, the product stability and release of bioactives such as micronutrients, antimicrobial compounds and antioxidants. The smaller size of nanomaterials provides higher thermodynamic and kinetic stability. Whereas the higher surface area enhances compound solubility. Nanoemulsions both encapsulate bioactive compounds effectively and address the food safety concerns of the fresh produce associated with foodborne pathogens. Nanoliposomes encapsulate bioactive whey peptides and fat-soluble vitamins with improved functionalities. Encapsulated bioactive molecules are released by diffusion into the surrounding environment after degradation of the surrounding polymeric matrix.

Nanotechnology in Food Processing and Packaging

Food products are complex mixtures including proteins, carbohydrates and lipids that are shaped at the nanoscale. These food nanomaterials are either naturally present within foods or created during transformation of initial products. Recent research has revealed several applications of food-based nanomaterials for food processing and packaging. For instance nanoparticles protect and control the delivery of antimicrobial compounds, lipid-soluble vitamins, flavours and antioxidants. Nanoparticles are also used as delivery vehicles such as pickering emulsions, multi-layered emulsions and solid-lipid nanoparticles. Nanosensors can detect rapidly toxic substances in food. In food packaging, nanoparticles can protect functional ingredients such as antimicrobials or vitamins. Chitosan nanoparticles are used as antimicrobial compounds to enhance food safety.

The mode of antimicrobial action of curcumin depends on the delivery system: monolithic nanoparticles vs. supramolecular inclusion complex

Curcumin has been known for a long time for its antimicrobial properties that are further increased by exposure to light. Due to the low aqueous solubility of curcumin, appropriate delivery systems are required to facilitate its implementation. In this work, we compared the antimicrobial activity toward Escherichia coli of two curcumin formulations: methyl-β-cyclodextrin supramolecular inclusion complex and polyelectrolyte-coated monolithic nanoparticles. The two formulations showed disparity both in the extent and in the mode of toxicity, highlighting the distinct properties of materials at the nanoscale. The tests showed that while curcumin–β-cyclodextrin complexes exhibited a potent bactericidal activity, the curcumin nanoparticles were bacteriostatic. Illumination with blue light significantly increased the bactericidal efficacy of curcumin–cyclodextrin complexes but had limited influence on the activity of nanoparticulate curcumin. While the antimicrobial effect of the supramolecular complex was predominantly characterized by the increase in ROS and inhibition of electron transport, the primary attributes of the nanoparticle action were membrane depolarization and reduced ATP concentrations. Interestingly, the treatment with curcumin nanoparticles induced a filamentous phenotype of the bacterium. Our results suggest that the antimicrobial properties of curcumin depend upon a delivery formulation, which may have both practical and regulatory implications on the applicability and safety of curcumin nanomaterials.

The Effect of Microwave Drying Parameters on the Germination of Wheat Seeds

In order to prevent germination damage of harvested wheat seeds, faster drying techniques are preferred. Microwave drying is considered an energy efficient technique to achieve this goal. The objective of this study was to investigate the effects of microwave (MW) drying on germination of wheat, using a domestic microwave oven.