Air Oven Research Articles

Artificial neural network modelling approach of drying kinetics evolution for hot air oven, microwave, microwave convective and freeze dried pineapple

This study presents the dehydration characteristics of the drying of the pineapple slice. Hot air oven (60 °C), microwave (100 W), microwave convective (600 W, 40 °C) and freeze drying (0.1 mbar, − 40 °C) of pineapple slice through artificial neural network (ANN) modeling approach (Backpropagation algorithm for feed-forward network). Considering the sample thickness of 0.15 cm, effective moisture diffusivity is calculated. To study the reconstitution property of the product, the rehydration ratio is considered at 20 °C, 40 °C, 60 °C and 80 °C. The microwave convective drying (96 min) is the fastest while the freeze drying is slowest (20 h). The coefficient of correlation through the ANN model for hot air oven, microwave, microwave convective and freeze dried sample are 0.99936, 0.9994, 0.99948, and 0.99926 respectively. In terms of rehydration ratio, freeze drying (5.49) is found best followed by microwave (4.62), hot air (4.50), and microwave convective drying (2.00). At 80 °C the coefficient of rehydration value attains the maximum of 0.969 for freeze dried sample, whereas the minimum value of 0.369 is observed at 20 °C for the microwave-convective dried sample. From the observations obtain it may be stated that the ANN model predicts the dehydration kinetics adequately for the entire drying process. Freeze dried product appears to be the best in terms of reconstitution properties.

Standardization of ultra- seed drying of okra cv. Kashi Kranti with Zeolite beads and silica gel

Ultra-dry storage, also called low moisture content storage, is a technique for decreasing seed moisture content to below 5-6 per cent using different methods and then stored hermetically at ambient temperatures. Though sun drying is common practice to dry the seeds, it is difficult to bring down seed moisture where high humidity and high temperature is frequently fluctuating. Use of seed dryer also a best alternative to reduce the seed moisture. But it may affect the viability due to temperature fluctuation at the time of seed drying. Zeolite beads (aluminum silicate) and silica gel are desiccants, which can be utilized to Ultra- dry the seeds even in fluctuated temperature and RH without affecting quality of seeds. In this study, standardization of the drying method performed by mixing okra cv. Kashi Kranti seeds with zeolite beads and silica gel, separately, in the ratio of 1:0.5, 1:1, 1:2 and 1:3 (seed: desiccant, by weight) in an air tight container and kept at room temperature. Initial moisture content of seeds (10.5%) was estimated by hot air oven method. Seeds were separated from desiccant and estimated for moisture content after 24h, 48h, 72h, 96h and 120h of drying. Moisture content of the seeds was noted down at every 24h interval. At the end of the experiment, final moisture content of dried seeds was estimated. It was observed that seed drying with zeolite beads was faster than silica gel. Significantly higher moisture content was removed from seeds by zeolite beads, and final moisture content of seeds dried with zeolite beads reached 4.59% in 1:3 ratio, which was higher moisture elimination than seeds dried with silica gel in the same ratio 6.21%. Since, hard seed formation is a problem in over dried okra seeds, germination test were conducted to know the germination (%) and vigour of dried seeds. Germination test reveals no reduction in germination (%) and no hard seed formation even in 1:3 ratio of seeds with zeolite beads. More than 80% germination was observed in all drying conditions and non-dried control which was on par with each other’s. Further work is necessary to know the storability of ultra-dried seeds under air tight condition.

Screening of different thermal heating processes for increased methane production from lignocellulose waste material

Pretreatment plays an important role in enhanced methane production from lignocellulose material. In this study, four different types of heating processes such as hot air oven, autoclave, liquid hot water bath, and microwave oven were used for comparison. The study was carried out in a biochemical methane potential assay to evaluate the different thermal heating process for enhanced methane production. Methane yield was increased in varied proportions with reduced digestion time for different heating processes of thermal pretreatment with low heating temperature at high residence time. Hot air oven pretreatment (17.92%) showed a high yield of methane production followed by autoclave (13.44%), microwave oven (9.54%), and hot water bath (7.54%) than control samples. In addition, the effect of pretreatment on biodegradability was assessed with three different kinetic models. Modified Gompertz model presents similar experimental data with a high degree of best fit when compared with the other two models.

Studies on the Proximate Contents and Potentials of Musa sapientum and Persea americana Fruits Peel as Media for the Growth of Medically Important Fungi

Aim: The present study was designed to formulate growth media for medically important fungi using banana and avocado fruits peel.
 Methodology: The peels were obtained from fresh banana and avocado fruits and dried into crisps at 100oC using hot air oven, pulverised into powder using Hammer mill machine and sieved into fine powder using 1 mm sieve size. Pure isolates of Aspergillus flavus, Aspergillus fumigatus and Cladosporium sp. were obtained from the Diagnostic Laboratory of the Department of Microbiology, University of Nigeria, Nsukka and used for the study. Two different media, Banana Peel Agar (BPA) and Avocado Peel Agar (APA) were formulated. 2 g of each fruit peel powder was introduced into separate conical flasks, 1g of agar powder was added as solidifying agent and varied glucose concentrations (20%, 10%, 5% and 0%) was used as nutrient (carbon source) supplement. The prepared media was sterilized by autoclaving at 121°C for 15 minutes. The test organisms were inoculated aseptically onto the formulated media and incubated for 3 days at 37oC. Fungal growth was visually observed. For comparative analysis, Sabouraud dextrose agar (SDA) was used as control. 
 Results: The formulated media supported the growth of all the test organisms, although at varying degrees. BPA showed more suitability than APA, with the growth of the test organisms on BPA favourably comparable to that on SDA. Proximate analysis of the fruit peels indicated that the moisture, ash, fat, crude fibre, crude protein and carbohydrate contents of avocado peel were 7.35%, 14.65%, 0.10%, 9.75%, 6.57% and 61.58% respectively and 5.80%, 6.00%, 0.45%, 5.35%, 10.95% and 71.45% respectively for banana peel.
 Conclusion: Banana and avocado fruits peel can be utilized as alternative materials in the formulation of culture media for the in vitro cultivation of fungi for medical and research purposes.

Optimization of Variables that Influence Puffing Quality of Hot Air Oven Puffed Quinoa

Optimization of Variables that Influence Puffing Quality of Hot Air Oven Puffed Quinoa

Osmo-predried fluted pumpkin (Telfairia occidentalis) leaf and its nutri-economic evaluation

Purpose Leafy vegetables are known to be highly perishable because of high moisture content, which had resulted in applications of different preservative methods. However, these methods were not without certain limitations during storage. Osmotic pre-dehydration had been proved to be a better alternative because of high retention and improvement in nutritional qualities and stability during storage. This study aims to investigate the osmotic pre-dehydration of fluted pumpkin (Telfairia occidentalis) leaves. Design/methodology/approach Fluted pumpkin (T. occidentalis) leaves were pre-dried using sucrose, corn syrup and sodium chloride solutions as osmotic agents, while unosmo-predried leaves were used as the control. Both osmo-predehydrated and unosmo-predried leaves were dried in a hot air oven, whereas the effect of the osmotic agents on the nutritional qualities was investigated using standard protocols. Findings There were significant differences (p-values ranged from 0.001 to 0.030) in the proximate compositions of samples. Osmo-predried leaves recorded higher mineral contents in Ca, Cu, Fe, K, Mg, Mn and Na. Osmotic pre-dehydration by NaCl had a significant effect (p = 0.02) on ascorbic acid. The amino acid profile of the oven-dried leaves (unosmo-predried) showed that histidine and cysteine recorded high amino acid scores of 120.42% and 135%, respectively. Threonine (43.73%) recorded the highest essential amino acid score (without histidine). The economic evaluation indicated the percentage cost index difference of leaves treated with NaCl as 2.08%, sucrose (11.19%) and corn syrup (16.43%). Originality/value The high proportion of beneficial elements such as calcium, magnesium, phosphorus, potassium and appreciable chemical compositions of the osmo-predried leaves compared to unpre-dried leaves proved osmotic pre-dehydration as a value-added technique for preservation of leafy vegetables. The best osmotic agent was sodium chloride. This process could be applied on a small scale for the development of self-entrepreneurs and home-scale industries.

Physicochemical, Sensory and Microbial Qualities of Ice Cream Stabilized with Hydrocolloids from Achi (Brachystegia eurycoma) and Ofor (Detarium microcarpum)

Aims: To investigate the physicochemical, sensory and microbial qualities of ice cream stabilized with hydrocolloids from Achi (Brachystegia eurycoma) and Ofor (Detarium microcarpum.
 Study Design: A 4×5 split-plot in completely randomized design.
 Place and Duration of Study: Department of Food Science and Technology, Faculty of Agriculture, University of Nigeria, Nsukka, Enugu State Nigeria between August 2018 and July 2019.
 Methodology: Raw seeds of Achi (Brachystegia eurycoma) and Ofor (Detarium microcarpum) were purchased from Ekeonunwa market, Owerri, Imo State, Nigeria and processed into flours. Hydrocolloids from flours of Achi and Ofor were defatted with n-hexane (50 g/250 ml at 26±2°C) dispersed in distilled water (10 g/250 ml), centrifuged (1250 rpm/30 mins and 1500 rpm/30 mins for achi and ofor respectively). The supernatants obtained were dissolved in isopropanol, decanted dried in a hot air oven (60°C, 10 h), pulverised using a blender and stored in air –tight containers. Twenty (20) litres of ice cream samples were produced. Four (4) litres of the mix was measured out as control (i.e. plain ice cream without any stabilizer). Sixteen (16) additional ice cream mixes were produced in the same way by the addition of CMC, achi hydrocolloids, ofor hydrocolloids and a mixture of hydrocolloids from both achi and ofor as stabilizers, each at 0.1%, 0.2%, 0.3%, 0.4% concentrations. The physicochemical, sensory and microbial properties of the ice cream samples formulated were carried out.
 Results: The outcome of physicochemical analysis revealed that viscosity (31.65 ± 0.17 cP – 82.50 ± 0.00 cP), overrun (19.30 ± 0.00% - 98.73 ± 0.00%), total solids (24.36 ± 0.33% - 54.00 ± 1.55%) and melting resistance (36.50 ± 0.58% - 92.50 ± 0.58%) were significantly (P < 0.05) affected by the type of stabilizers as well as their concentrations. The total titratable acidity (0.02 ± 0.00% - 0.02 ± 0.00%) and pH (6.74 ± 0.00 - 7.05 ± 0.05) of the ice cream samples showed no appreciable significant (P > 0.05) difference. The overall acceptability (5.80 ± 1.99 - 7.65 ± 1.00), aftertaste (5.45 ± 2.28 – 7.20 ± 0.89), mouthfeel (5.85 ± 1.79 - 7.25 ± 1.37) and homogeneity (5.20 ± 1.96 - 7.60 ± 1.39) were significantly (P< 0.05) influenced as deduced from the sensory result.
 Conclusion: The incorporation of local stabilizers significantly improved the physicochemical, sensory and microbial qualities of ice cream produced. Hydrocolloid extracts of Detarium microcarpum (Ofor), plant-based natural stabilizer is a capable replacer of CMC in ice cream production because of its higher viscosity than other stabilizers and CMC, agreeable consistency, better consumer preference than other stabilizers, enhanced qualities – slow melting rate i.e. high melting resistance, commendable pseudo-plasticity, effectual overrun which will yield more profits for ice cream manufacturers, bring about a new variety of ice creams that are safe for consumption. Hydrocolloid extracts of Detarium microcarpum, at 0.3%, showed more desirable similar effects on the physicochemical, sensory and microbial qualities of ice cream samples formulated compared to CMC and could, therefore be recommended as a replacer of CMC in ice cream production.

Thin layer drying of green microalgae (Chlorella sp.) paste biomass: Drying characteristics, energy requirement and mathematical modeling

The characteristics, energy requirement and kinetics of open sun, solar, hot air oven (50–70 °C) and microwave (450–700 W) thin layer drying of green microalgae (Chlorella sp.) paste were investigated. Drying took place mainly in the falling rate period. The moisture diffusivities for the open sun, solar, hot air and microwave drying were 4.64 × 10−10, 6.46 × 10−10, 5.91 × 10−10–1.10 × 10−9 and 1.83–3.91 × 10−9 m2 s−1, respectively. Activation energies for hot air and microwave drying were 28.7 kJ mol−1 and 21.4 W g−1, respectively. The specific energies required for hot air and microwave drying were 51.7–55.1 kWh kg−1 water and 26.2–34.9 kWh kg−1 water, respectively. Kinetics of open sun, solar, hot air and microwave drying were suitably described by the Wang and Singh, Wang and Singh, Weibull and Verma models, respectively.

Pilot multi-site quality assurance study of batch-mode clinical-scale automated xenon-129 hyperpolarizers

We present a pilot quality assurance (QA) study of spin-exchange optical pumping (SEOP) performed on two nearly identical second-generation (GEN-2) automated batch-mode clinical-scale 129Xe hyperpolarizers, each utilizing a convective forced air oven, high-power (~170 W) continuous pump laser irradiation, and xenon-rich gas mixtures (~1.30 atm partial pressure). In one study, the repeatability of SEOP in a 1000 Torr Xe/900 Torr N2/100 Torr 4He (2000 Torr total pressure) gas mixture is evaluated over the course of ~700 gas loading cycles, with negligible decrease in performance during the first ~200 cycles, and with high 129Xe polarization levels (avg. %PXe = 71.7% with standard deviation σPXe = 1.5%), build-up rates (avg. γSEOP = 0.019 min−1 with standard deviation σγ = 0.003 min−1) and polarization lifetimes (avg. T1 = 90.5 min with standard deviation σT = 10.3 min) reported at moderate oven temperature of ~70 °C. Although the SEOP cell in this study exhibited a detectable performance decrease after 400 cycles, the cell continued to produce potentially useable HP 129Xe with %PXe = 42.3 ± 0.6% even after nearly 700 refill cycles. The possibility of “regenerating” “dormant” (i.e., not used for an extended period of time) SEOP cells using repeated temperature cycling methods to recover %PXe is also demonstrated. The quality and consistency of results show significant promise for translation to clinical-scale production of hyperpolarized 129Xe contrast agents for imaging and bio-sensing applications.

Effect of in-vitro digestion on the bio active compounds and biological activities of fruit pomaces.

The effect of gastro intestinal digestion on total phenolic contents (TPC), total flavonoid contents (TFC), radical scavenging activity (RSA) and vitamin C levels of apple (Malus domestica) pomace and a local variety of jujube (Ziziphus mauritiana) pomace was evaluated after drying at 110°C for 3h in a hot air oven. The physicochemical properties and functional properties of apple and jujube pomaces were also assessed. Prior to digestion, apple pomace displayed greater levels of TPC, RSA and vitamin C (17.30 ± 0.59 GAE/g DW, 81.16 ± 3.27%, 0.078 ± 0.01g/L, respectively) in comparison with jujube pomace (16.90 ± 0.66 GAE/g DW, 54.65 ± 2.09%, 0.069 ± 0.01g/L, respectively), whereas, TFC level was found to be higher in jujube pomace (19.22 ± 0.87 QE/g DW). After digestion, both samples showed an increase in TPC (56.17 ± 2.14 and 52.01 ± 2.18 GAE/g DW for apple and jujube pomaces) and TFC levels (48.45 ± 1.87 and 53.82 ± 2.34 QE/g DW for apple and jujube pomaces) and it was perceived almost 3 to 4 times higher than the TPC and TFC of the samples before digestion. But, RSA of the fruit pomaces were found to be affected by the in vitro digestion which was observed as 54.65 ± 2.09 and 81.16 ± 3.27% respectively for apple and jujube pomaces. It may be suggested that the fruit powders may be incorporated in developing new functional foods rich in bio active compounds and thus can be utilized in different food applications.

Osmo-solar drying of bottle gourd (Legeneria Siceraria)

The bottle gourd is a common vegetable in India subcontinental. Osmotic dehydration increases the storage ability of fruits and vegetables making them available throughout the year. Dehydrated products also play a great role in processed foods of all kinds and the way to achieve high quality dehydrated products are desired. The combination of osmosis with solar drying has been put forward, mainly for tropical fruit. A 24-hour cycle has been suggested combining osmodehydration, performed during the night, solar drying during the day. The well washed bottle gourd fruits were then peeled off with help of stainless-steel hand peeler. Pieces of bottle gourd cubes (1cmx1cmx1cm) were then cut out using a ruler and knife. The salt solution with 5, 10, 15, 20, and 25% (w/w) concentration were prepared. Bottle gourd cubes were immersed in the osmotic reagents with a fruit to osmotic solution mass ratio of 10:1, 20:1 and 30:1 soaking experiments were conducted at 400C, 500C and 600C in a 500 mi capacity water bath. The osmotic dehydration was done for a period of 1, 3, 5, 7 and 9 h and replicated thrice. The dependent variable studied was moisture content after dehydration. Moisture content of sample was determined by standard air oven method (Ranganna, 1995). The minimum moisture content was 46.9% (wb) for samples osmotically dehydrated at 600C for 9 h at 30:1 fruit to osmotic solution at 25% concentration. The moisture content of bottle gourd cubes observed decreases with higher concentration, temperature and mass ratio. Solar drying characteristics of 9 h bottle gourd cubes at 600C are determined by solar tray dryer. During the process of solar drying of 9 h bottle gourds cubes, the air temperature inside the cabinet varies 44 to 810C. and relative humidity inside the chamber was measures 34 to 58 percent. The minimum value of final moisture content of osmo-solar dried bottle gourd cubes was 8.3% at 600C for sample of 10:1 mass ratio and maximum value of final moisture content was 24.4% of at 600C for 30:1 sample.

Comparative Evaluation of MTA and Biodentine as a Restorative Material In Deciduous Teeth

Introduction: Several medicaments have been used in pulpotomy procedures of primary teeth. The present study was conducted to compare MTA with biodentine as a restorative material in deciduous teeth. Materials & Methods: Specimens were prepared with MTA (group-I) and Biodentine (Group-II) with mold with 10 in each group using stainless steel ring molds. Polyethylene tubes of 1 mm long were filled with MTA and biodentine and placed in flasks containing 10 ml distilled water at 37°C. After 2 h, the flasks were removed from hot air oven, and the water was assessed for pH. Results were tabulated and subjected to statistical analysis. Results: Each group had 20 teeth sample. In group I, MTA was used and in group II, biodentine material was used. The mean solubility value of MTA at 1st day was 1.55, at 4th day was 1.64, at 12thday was 2.15, at 30th day was 2.57 and at 45th day was 2.60. Similarly in group II at 1st day was 1.89, at 4th day was 2.11, at 12thday was 2.80, at 30th day was 3.61 and at 45th day was 5.34. pH at 2 hours was 9.28 in group I and 8.98 in group II, at 12 hours was 9.26 in group I and 9.39 in group II, at 24 hours was 9.20 in group I and 9.64 in group II, at 7 days was 8.76 in group I and 8.27 in group II, at 28 days was 7.62 in group I and 7.78 in group II. The difference was significant (P< 0.05). Conclusion: Authors found that both materials can be used in deciduous teeth. However, biodentine revealed higher solubility and pH as compared to MTA in deciduous teeth.

Preparation and Characterization of Nano-Hydroxyapatite Particles and Chitosan by Sol–Gel Method (in Vitro Study)

Successful osseointegration of dental implants depends on many factors, including implant stability, bone quality, implant surface condition, and implant materials. Implant surface is coated using different techniques to enhance osseointegration. Sol–gel technique is one of the modern and easy techniques in the production of more bioactive hydroxyapatite (HA). In this study, nano-HA and chitosan were used to coat titanium disc via the sol–gel technique. Materials and Method: The nano-HA/chitosan composite was prepared using calcium nitride and phosphorus pentoxide solutions. The solutions were drop wisely mixed on a magnetic stirrer. Then, 3 mg of chitosan was added to the mixture, and the mixture was stirred for 15 h. Titanium samples were dip coated in the mixture of chitosan/HA on the stirrer at slow speed for 90 min to precipitate the coating layer. Afterward, the samples were removed and dried in a hot air oven. They were sintered at 400 °C for 1 h. X-ray diffraction (XRD), light microscopy, scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), FTIR analysis, and atomic force microscopy (AFM) were used to analyze the surface and thickness. The results of XRD test showed that HA particles had sharp diffraction peaks, indicating high crystallinity of the structure due to the sol–gel preparation. Results of optical light microscopy showed that the coated layer was fairly distributed on titanium samples. SEM results of the coated samples showed different surface features, which present a roughness with the appearance of a crystal pool with irregular accumulation of small, spherical-like granules. EDX analysis showed the presence of ions that comprised HA. AFM analysis of the coated sample indicated peaks and projections with average surface nano-roughness (10.1 nm) and grain size (2022–2057 nm). FTIR analysis showed the presence of a band associated with HA particles and amide groups associated with chitosan. The average of thickness readings was 60 ?m.

Development and characterization of alkali-treated and untreated Dactyloctenium aegyptium fibers based epoxy composites

Natural fibers are widely used as they are ecofriendly and abundant in nature. The performance of the natural fibers is enhanced by chemical treatment. The current study deals with the extraction of Dactyloctenium aegyptium (DA) fibers, commonly known as “Crowfoot grass” using a conventional retting process. The obtained fibers were subjected to alkali treatment using NaOH followed by distilled cleaning to remove traces. This was followed by drying in sunlight and in a hot air oven. The obtained alkali-treated Dactyloctenium aegyptium fibers were mixed with an epoxy-hardener mixture in the ratio (60% matrix and 40% fibers) to form laminates using conventional hand lay-up process in comparison with untreated fibers. The final composite laminates were subjected to mechanical behavior namely tensile, flexural, impact as per ASTM. Test results showed that alkali-treated Dactyloctenium aegyptium fiber based epoxy composites had better mechanical properties with an ultimate tensile strength of 57 MPa compared to those untreated (45 MPa) due to the removal of amorphous constituents from the fiber leading to better interlocking properties with the matrix. These results prove that Dactyloctenium aegyptium fiber based epoxy composites can be used for lightweight and medium load applications.

Preparation and evaluation of matrix type gastro retentive floating atenolol tablets using sintering technique.

The aim of this investigation was to design and assess the gastric floating tablets of Atenolol using thermal sintering and investigate the effect of sintering on PEO polymer. Atenolol is an Antihypertensive with only 50 percent bioavailability due to poor absorption in lower GI tract. Gastro retentive Floating tablets were prepared to enhance the gastric retention time, to prolong the drug release. PEO which was selected as sintered polymer. Tablets were prepared by direct compression method .Formulated tablets were exposed to different temperatures (400C, 500C and 600C) at various time intervals( 1h ,2h ,3h and4h) in a hot air oven .Post compression parameters were evaluated like weight variation, hardness, friability, floating lag time and total floating time. The result of the investigation indicates sintering influenced the floating time and dissolution properties. Weight variation, friability and content uniformity values were within limits. Sintering time and temperature contributes to effectiveness of polymers in extending drug release. Reduction in floating lag time and increase in total floating time as well as release of drug was delayed. All sintered formulation have no interaction was found in FTIR, DSC studies. All sintered tablets followed zero order with nonfickian diffusion mechanism. This study helps the use of thermal sintering in preparation of floating tablets.

Effect of drying methods and parameters on the antioxidant properties of tea (Camellia sinensis) leaves

BackgroundConventional drying using heated air oven is commonly used as a method for preserving the product but often affects the nutritional value, taste, and texture. However, the heat from the drying method can oxidize and destroy heat-sensitive compounds. Superheated steam (SHS) drying uses superheated steam instead of hot air or combustion gases in a direct dryer and was reported better at preserving the nutritional values of food products.AimTo evaluate the effect of SHS drying on antioxidant properties of tea leaves. The study also compared SHS drying with conventional and freeze-drying methods.ResultsTea leaves dried using freeze drying retained the highest level of antioxidant properties compared to other drying methods. The leaves dried using SHS exhibited significantly higher radical scavenging activity, ORAC and FRAP values compared to oven drying method. At different drying temperatures (150 °C and 175 °C), oven dried leaves showed significantly higher (p < 0.05) antioxidant properties than that of SHS dried ones. Tea leaves dried for 60, 75, and 90 min using SHS showed significantly higher (p < 0.05) FRAP and ORAC values, and also total phenolic content compared to oven dried tea leaves.ConclusionTea leaves dried using SHS drying method retained higher level of antioxidant properties compared to oven drying. The drying method also retained lower antioxidant properties as drying time increased. Further study involving SHS drying in food-related fields should be conducted to support its usefulness.Graphical abstract

The Oriented Attachment Model Applied on Crystal Growth of Hydrothermal Derived Magnetite Nanoparticles

Magnetite (Fe3O4) nanoparticles are very promising to be applied as a drug delivery system (DDS) for cancer chemotherapy. In this research, the crystal growth of hydrothermal derived magnetite particles was studied by oriented attachment (OA) model. The OA model was used to investigate the mechanism and the statistical kinetic of crystal growth. The crystal diameter change as a function of time with different concentration was measured using XRD. Firstly, 0.3248 g FeCl3 and 1.1764 g of sodium citrate, as well as 0.3604 g urea were dissolved into 40 mL of distilled water in a reactor. Subsequently, the reactor temperature was maintained at 210 °C and reaction time of 3.5–12 h in an air oven. The morphology of obtained particles was characterized using TEM, whereas VSM was used to determine the magnetic hysteresis curve. The XRD pattern showed that magnetite was obtained at temperature 210 °C and 3.5 h reaction time, as well as its intensity increased with reaction time. The crystal size of Fe3O4 was 9.44 nm at 3.5 h and appropriate with the oriented attachment model. The magnetite nanoparticles with shaped core-shell size less than 50 nm and suitable for biomedical application especially as drug delivery.

Effect of packaging materials on shelf life of dehydrated green chilli

The green chilli was dehydrated in a hot air oven. The dehydrated green chilli samples were packaged in low density polythene (LDPE) pouch, PET jar, and laminated film pouch and stored at room temperature for 28 days for storage study to estimate shelf life. Green chilli samples were evaluated based on sensory score for visual colour, texture, water activity and moisture absorption during storage at a regular interval of 7 days. Since no appreciable change in quality parameters, water activity and moisture absorption were found after 28 days of storage period stored in PET jar and laminated film pouch, dehydrated green chilli were acceptable. The increase in water activity and moisture absorption was high in LDPE pouch in comparison to PET jar and laminated film pouch. From the storage study, it was found that the shelf life of dried green chilli could be increased to more than 28 days.

The effectiveness of short-term microwave irradiation on the process of seed extraction from Scots pine cones (Pinus sylvestris L.)

The influence of short-term microwave irradiation on the process of seed extraction from Scots pine cones was investigated in this study. Cones from the Brzesko Forest District (near Kraków, southern Poland) were collected in 2015. The size and changes in the mass of cones during the process of seed extraction, as well as the relations between these parameters, were analyzed. Changes in water content and drying rate of cones were modeled using suitable mathematical equations. The thermal balance of the whole process of seeds extraction was calculated, and the heat necessary to extract the seeds was determined. Cones were initially exposed to 2.45 GHz microwaves with a power of 800 W for either 5 or 15 seconds. Subsequently, cones were placed in a circulating air oven and seeds extracted under convective drying at a constant temperature of 50 ± 0.1 °C. We found that seeds from cones subjected to 15-seconds microwave radiation were dramatically damaged, while no significant difference were found in germination and quality of seeds between cones subjected to the 5-seconds microwave pre-treatment and control cones, both yielding first-class quality seeds (mean germination capacity > 90%). The results of this study could help developing microwave-dryer control algorithms to support the automated process of cone seed extraction in large-capacity extraction plants.

Elastomeric Composites Containing SBR Industrial Scraps Devulcanized by Microwaves: Raw Material, Not a Trash

Environmental concerns about waste management systems have stimulated the search for technological and economical alternatives that introduce waste as raw material for production cycles. In this sense, this study aimed to develop and characterize styrene-butadiene rubber (SBR) composites that contain industrial rubber scraps devulcanized by microwaves (SBR-r) as a reinforcing filler. The scraps were ground under ambient conditions. From the obtained powder (SBR-r), composites were prepared, varying the exposure time of the powder to the microwaves (1, 2, and 3 min), as well as the SBR-r content. These composites were compared to a Reference sample (base formulation without SBR-r). The vulcanization parameters were determined by an oscillating disk rheometer. After vulcanization, the composites were characterized by mechanical properties (tensile and tear strength, and compression set). These properties were also evaluated after accelerated aging in an air oven and a UV chamber (ultraviolet light). The results indicated that as a result of increasing the exposure time of the waste to the microwaves, no significant influence in the composite properties was observed. Aged samples presented higher results as compared with the Reference sample (tensile strength up to 175% higher, tear strength up to 107% higher, and compression set up to 91% higher), which indicates the possibility of using these materials in technological applications, such as in the civil and automotive industries.