Oven-dried Samples Research Articles

Drying kinetics and mathematical modeling of coconut meat slices: Insight into pretreatment and drying synergic effect

Coconut consumption provides nutritional and health benefits to humans. Yet, poor postharvest and preservation methods result in the loss of coconut fruit bunches yearly. Investigations into achieving drying techniques that result in optimum drying rates coupled with consumer's desired end products that are both commercially and nutritionally viable remain paramount in the food industry. Consequently, osmotic dehydration is commendable for its low-cost pretreatment merit. Therefore, the study examined the drying-kinetics, energy consumption, effective moisture diffusivity (Deff), vitamin C retention, color, and rehydration behavior of coconut cultivars (Sri Lanka Green Dwarf × Vanuatu Tall (SGD × VTT), Catigan (CAT), and Tacunan Green Dwarf (TGD)) meat slices. Samples were osmotically pretreated with sucrose solution (30 %/30 min) and subjected to oven drying (80, 90, 100, and 110 °C (air velocity of 2 m/s) and lyophilization (−45 ± 2 °C) methods. A mathematical model was employed to predict the effect of osmotic pretreatment on drying dynamics and the assessment of utilized energy, vitamin C content, color, and rehydration of coconut meat slices at different drying conditions. The oven-dried sample's color changed (p < 0.05) compared to lyophilized samples. Drying-kinetics models were validated using determination coefficient (R2) and root mean square error (RMSE). The Asymptotic model satisfactorily suited the samples' drying data goodness fitting based on R2≥0.90−0.99 and low RMSE ≤0.01−0.12 compared to other models for both drying methods. Deff ranged between 1.10 × 10−07 m2s−1 and 7.90 × 10−08 m2s−1 for all the drying methods. CAT sample retained high vitamin C content compared to SGD × VTT and TGD samples. Rehydration ratio values were significant at lower temperatures among oven-dried experimental samples whereas TGD samples exhibited a significant rehydration values compared to SGD × VTT and CAT lyophilized samples. Among the drying methods, oven drying exhibited low energy consumption with shorter drying time and optimum Deff per adopted temperature ranges compared to lyophilization. The study revealed that temperature, time, the sucrose solution, and the thickness of the coconut slices strongly influenced the drying kinetics of the osmotically pre-treated coconut meat slice's drying features.

EFFECTS OF PROCESSING ON THE PROXIMATE AND MINERAL COMPOSITION OF CULTURED AND CAPTURED CLARIAS GARIEPPINUS

Fish and fish products serve as vital protein sources in Africa and the world in general. Since fish is typically processed before consumption, this study investigated how different processing methods affect the proximate and mineral composition of both cultured and captured Clarias gariepinus. The processing techniques employed in this research included smoking, boiling, and oven drying. Cultured catfish were sourced from Oris Farm in Osogbo, Osun State, Nigeria, while captured catfish were obtained from Asejire Dam in Oyo State. The proximate and mineral compositions of fresh, boiled, smoked, and oven-dried samples of both cultured and captured Clarias gariepinus were analyzed in triplicate. The results indicated significant differences (P&lt;0.05) in crude protein, dry matter, moisture, ash, fiber, potassium, and phosphorus content among the different processing methods for both cultured and captured catfish samples. Potassium and phosphorus levels also varied significantly (P&lt;0.05) across the processing methods. Boiled and oven-dried samples of both cultured and captured catfish exhibited higher crude protein and lipid content, suggesting that these processing methods provide consumers with a rich source of protein and essential nutrients. The study concludes that boiling and oven drying with samples possessing highest percentages of protein are the most effective processing methods for preparing Clarias gariepinus, ensuring optimal nutrient retention for consumers.

Assessment of coffee leaves nutritive value via portable X-ray fluorescence spectrometry and machine learning algorithms

Portable X-ray fluorescence (pXRF) spectrometry is a non-destructive technique that has been successfully used to analyze different matrices. Foliar analysis is challenging because some plant nutrients cannot be detected by pXRF. Even so, the uptake interactions among nutrients which reflect different concentrations of macro- and micronutrients can be accessed via pXRF, constituting a basis to obtain predictive models of plant nutrients. The objective of this work was to compare and assess the accuracy of linear regression and non-linear models (support vector machine – SVM; and random forest – RF) to predict the actual concentration of macro- (N, P, K, Ca, Mg, and S) and micronutrients (B, Cu, Fe, Zn, and Mn) in coffee leaves. A greenhouse experiment was conducted using Hoagland and Arnon solution to obtain leaves with contrasting elemental composition. Ground and oven-dried leaf samples were analyzed via pXRF using: i) a manufactured pXRF calibration developed for general earth-materials (Geoexploration mode); ii) the Spectrometer mode with varying voltage and current (15 kV and 25 μA; 10 kV and 10 μA). The same samples were also analyzed via conventional acid digestion and quantified via inductively coupled plasma-optical emission spectroscopy (ICP-OES). The best predictions were obtained using SVM and RF algorithms, with high R2 (0.82 to 0.99) and high residual prediction deviation (RPD) (2.35 to 9.34) values. However, some elements (e.g., K, Ca, Cu, Mn) were successfully predicted using linear models (LR and MLR). Even elements not detected (N and B) by pXRF were accurately predicted using the RF model. The pXRF operational conditions influenced the performance of the models. However, by parsimony, Geoexploration mode provided data for accurate prediction of macro- and micronutrients. This comprehensive study can potentially spark further investigations into examining coffee leaves from plants cultivated under various environmental and management conditions. Additionally, the methodological framework outlined here holds promise for ongoing experimentation across diverse crops, offering a streamlined, non-invasive, eco-friendly, and rapid approach for foliar analysis.

Investigation of the qualitative and appearance characteristics of Eryngium caeruleum L. based on colorimetric and browning indices in storage conditions.

The eryngo plant is an herb related to the Apiaceae family with the greatest diversity of species, has a gorgeous taste when eaten as a vegetable, and is traditionally used in folk medicine for its health benefits. The present study was to assess the effects of different drying methods and storage times on the quality and appearance of Eryngium caeruleum. The treatments of this study were drying methods (room temperature (25°C) with proper ventilation, oven temperature 55°C, vacuum oven temperature 55°C, and a microwave with a power of 500 W) and storage times (1, 75, and 150 days). The lowest brightness index and the highest browning index were found in the shade-dried samples kept in the refrigerator for 150 days. In these samples, the numerical values of chlorophyll were lower than others. After 75 days, in the vacuum oven-dried samples, the maximum levels of total phenolics and flavonoids and antioxidant activity were calculated. The colorimetric test showed that the oven-dried samples maintained their green color well. However, the storage decreased the quality of plant samples due to the degradation of chlorophyll. Overall, this study showed that the highest greenness and appearance qualities were found in the samples dried in a vacuum oven at 55°C. It seems that appearance indices can be introduced as an initial and quick step in the qualitative assessment of dried leafy products.

Impact of NaCl concentrations and drying on the essential oil yields and composition of Murraya koenigii (L.) Spreng leaf

The objective of this study was to investigate how varying concentrations of salt (NaCl) and different drying methods affect the yield and composition of essential oil extracted from the leaves of Murraya koenigii (L.) Spreng. The findings revealed that fresh samples yielded significantly more essential oil (0.24%) than both dried samples and those treated with different NaCl concentrations (5, 10, and 15% NaCl). Gas chromatography analysis identified 12 chemical constituents, with α-phellandrene and lavandulol being the primary ingredients. Medium proportions of β-phellandrene and β-caryophyllene were also detected, along with eight other chemicals. Among the samples, the oven-dried sample exhibited the highest concentration of α-phellandrene (44.205%), while the sample treated with 15% NaCl had the lowest concentration (33.064%). The difference in the α-phellandrene concentration between the fresh and oven-dried samples was significant (8.011%). The lavandulol concentration was highest in the 15% NaCl sample (27.905%) and lowest in the oven-dried sample (23.577%), with no notable variation observed among the dried, NaCl-treated, and fresh samples. β-Phellandrene was highest in the 5% NaCl sample (9.216%) and lowest in the fresh sample (6.77%). No significant variations were observed in the concentration of β-caryophyllene across all the samples. The elevated β-phellandrene content in M. koenigii essential oils by a particular treatment suggests potential market competitiveness and enhances the commercial viability of these oils. Keywords: Murraya koenigii, Drying, Salt media, Essential oil, Gas chromatography.

Influences of root fragments on soil thermal property measurements with heat pulse method

Heat pulse (HP) method has been widely applied for measuring thermal properties, heat fluxes, and soil–water evaporation for near-surface soil layers. In topsoil layers, the presence of roots violates the underlying assumption of HP method that the soil under test is homogeneous. In this study, numerical and laboratory experiments were conducted to test the influence of root fragments on soil thermal property measurement with HP sensors. Soybean root fragments, with a water content of about 0.74 m3 m−3 and diameters ranging from 0.5 to 4 mm, were carefully repacked into soil samples that were used for HP measurements. Results showed that the effects of roots on soil thermal property measurements depended on root size, root location and directions relative to the heater probe, and the thermal property differences between soil sample and root. Roots showed negligible influence on heat pulse data when the root fragments were positioned outside the HP measurement region (more than probe space away from heater probe), or root diameters (d) were less than 1 mm, or in oven-dried soil samples. On relatively wet soils (i.e., with water content of 0.05–0.25 m3 m−3), when root fragments were located in between the heater and sensing probes (parallel to the probe planes), (1) the heat capacity (C) and thermal conductivity (λ) differences between root-free soil and root-soil mixture increased proportionally with d increased from 1 mm to 4 mm; (2) the differences in absolute values of C and λ between the root-free soil and soil-root mixture were highly dependent on soil water content. The errors in soil C and λ estimates were larger when the root fragment was parallel with than perpendicular to or inclined 45 degrees to the probe plane, and the error overall decreased with a smaller ρb and sand fraction. When the root fragments were positioned within the HP measurement region, or d were larger than 1 mm, or in relatively wet soil samples, it is important to consider root effect when interpreting HP signals.

Sorption Isotherm and Effect of Packaging Materials on Proximate, Organoleptic and Lipid Oxidation Quality of Chicken Nuggets Stored at Two Different Temperatures

The study Investigated sorption isotherm features and the effects of packaging materials of both high-density and low-density polyethylene on sensory properties, proximate composition and lipid oxidation of chicken nuggets in storage. Boneless chicken breast was procured from a reputable source and cut into sizeable weight of 50g each to produce the chicken nuggets used for the studies. The experimental setup for sorption isotherm analysis in this study involved using a gravimetric method to equilibrate the product at various relative humidity levels. Five (5g) grams of oven-dried chicken nugget samples of known moisture content were placed in a controlled humidity chamber, and the weight changes of the samples were monitored until equilibrium was reached. GAB equation was used to evaluate the product ware activity and monolayer moisture. Sensory assessment was evaluated using a 9- point hedonic scale while proximate composition of the chicken nuggets samples was determined according to the methods of the Association of Official Analytical Chemists. Thiobarbituric acid reactive substances (TBARS) assay was used to measure malondialdehyde (MDA) levels as a marker of lipid oxidation. The investigation showed that sensory qualities, proximate composition and lipid oxidation of chicken nuggets were markedly affected by the variance in temperature settings, with distinct disparities seen among different materials for packaging. Chicken nuggets stored at 25 0C caused a significant loss in organoleptic properties and some nutritional composition such as protein and fat. Storage of chicken nugget at 25 0C and 40 C showed a varied values in malondialdehyde as content ranged from 0.52 to 0.81 for chicken nugget stored at 250 C and 0.17 to 0.43 for the product stored at 40 C across the packaging materials investigated. The water activity and monolayer moisture results of sorption analysis revealed that good packaging materials of very low water vapour transmission rate should be used for storage of chicken nuggets as high-density polyethylene offered a promising alternative than low density polyethylene.

SORPTION ISOTHERM, PROXIMATE COMPOSITION AND SENSORY EVALUATIONS OF OVEN DRIED AND FRIED CHEESE PRODUCTS FROM LOCAL SOFT CHEESE

In this study, the sorption isotherm, proximate composition and sensory characteristics of oven dried and fried cheese were investigated. The understanding of the moisture sorption properties, nutrient composition and sensory properties of the oven dried and fried cheese can help quality, shelf-life prediction and overall acceptance. The experimental methodology for this study followed a standard procedure to determine the sorption isotherm of oven-dried and fried cheese samples. First, the raw milk samples were obtained from white Fulani cows at the Teaching and Research Farm, Ekiti State, University, Ado-Ekiti, Nigeria and processed into cheese. The cheese was divided into two portions: one group was oven-dried at 50 0C for 16 hours, while the other group was fried in pre-heated edible canola to internal temperature of 68oC. Sorption parameters, proximate and sensory characteristics were carried out according to standard methods. This study revealed that the monolayer moisture was higher in fried cheese than oven dried cheese. Oven-dried cheese had 0.299 water activity and 21.26 monolayer moisture while fried cheese had higher water activity of 0.32 and monolayer moisture of 29.67. Fitness of curve (R2) of 0.731 0.903 were computed for oven-dried and fried cheese. The results of proximate composition and sensory characteristics showed that processing methods influenced the sensorial properties and nutritional composition of oven-dried and fried cheese. In conclusion, oven-dried cheese can be predicted to be more stable than fried cheese. KEYWORDS: Adsorption, Equilibrium, GAB Equation, Monolayer, Salts.

COMPARATIVE ANALYSIS OF EROSION RESISTANCE BETWEEN TERMITE MOUNDS AND SURROUNDING SOILS IN NIGERIAN DEFENCE ACADEMY, AFAKA, KADUNA STATE, NIGERIA

A combination of chemical elements, organic matter and rainfall weaken surface rocks and render them liable to water erosion, but insignificantly affect termite mounds. The study is embarked upon to identify the concentration of Ca, Fe, Na, C, and organic matter content in termite mounds and adjacent soils to deduce the influence of resistance of termite mount to erosion. Data on the chemical elements and organic matter contents were generated through laboratory tests using heat, and an Atomic Absorption Spectrophotometer to read the values. The percentage of the chemical elements was calculated as: Instrument Reading multiplied by Extraction Volume 50ml divided by the weight of samples. The percentage of organic matter contents were determined using weight loss on ignition by an oven-dried soil sample. The set of data was analyzed by comparing the difference in magnitude of the chemical concentration and organic matter content in both the samples. The values differ insignificantly by 0.02%, 0.001%, 0.21%, 0.01%, and 0.24% for Ca, C, Fe, Na, and organic matter respectively. From the result, the resistance of termite mound to erosion is not influenced by the chemical concentration and organic matter content, but due to the maintenance of the mound by the termites, tapering end toward the atmosphere, fairly straight with steep slopes, and have dome shape that reduces effects of forceful fall of the raindrop. Further study should be conducted to determine the influence of chemical elements and organic matter on surface erosion for sustainable development of soils.

Effects of Postmanufacture Conditioning on the Mechanical and Hygroscopic Properties of Extrusion Printed Wood–Sodium Silicate Composites

Abstract Additive manufacturing of wood–sodium silicate composites could aid in mitigating the carbon footprint of the building and construction industry. However, the effect of postmanufacture conditioning on the mechanical and physical properties of additively manufactured wood–sodium silicate composites is not well understood. This study investigated eight different postmanufacture drying processes, including: ambient indoor and outdoor conditions, oven-drying at two different temperatures, microwave drying, alcohol-induced dehydration using ethanol and denatured alcohol, and desiccant drying. Each postmanufacture conditioning treatment was assessed in terms of total moisture extraction and moisture extraction rate as well as the flexural strength, flexural stiffness, and hardness of the wood–sodium silicate samples after drying. In addition, the water absorption and volumetric swelling properties of the additively manufactured wood–sodium silicate samples were assessed via water submersion tests. The postmanufacture conditioning treatments were found to significantly affect the mechanical and physical properties of the samples. A universal ranking system was established based on cumulative rankings of each evaluated characteristic. Samples dried in ambient outdoor conditions achieved the best overall ranking and had the smallest carbon footprint. However, ovendried samples had the best flexural properties. Future studies investigating hybrid approaches in which composites are sequentially subjected to different drying methods will likely provide the most desirable mechanical and physical properties of wood–sodium silicate composites.

Quality evaluation of house cricket flour processed by electrohydrodynamic drying and pulsed electric fields treatment

House crickets are expected to play a significant role in the future food sector. Electrohydrodynamic (EHD) drying offers an environmentally friendly alternative to conventional drying methods. Pulsed electric fields (PEF) is a non-thermal process that facilitates conventional processes. EHD was applied to house crickets with and without PEF pretreatment, and the effect of PEF and EHD on the quality of the insects was evaluated. PEF pretreatment positively affected the oven drying at 60 °C by reducing its duration and thus decreasing the energy consumption by 14.22%. Moisture removal of EHD was not sufficient to replace oven drying, but when combined with oven drying, the overall energy consumption was reduced by >50%. PEF processing also increased the protein solubility (53.07% higher than the respective control) and antioxidant activity (24.05% higher than the respective control) of the oven-dried samples and reduced the histamine content of the EHD-dried samples (25.87% lower than the respective control).

Usporedba reakcijskoga i normalnog drva nekih komercijalnih vrsta drva

This study aims to analyze the reaction wood samples for some industrial tree species naturally grown in Kastamonu province in Turkey and compare them with the relevant standards. Some anatomical, chemical, fiber morphological, optical properties, and color changes before and after drying were analyzed for the reaction wood (RW) samples. While the holocellulose content of fir and pine compression wood (CW) was found to be lesser (~3-4 %), the lignin content was higher than those of the opposite wood (OW) (~34 % for pine and 12 % for fir). On the contrary, the amount of holocellulose was found to be higher (~1-4 %), and the lignin was lower (at about 6-15 %) in the tension wood (TW) samples. It was observed that average lengths are more extended in TW(~50-54 %) and shorter in CW (~13-17 %) than those of OW. Significant differences were observed between the anatomical structures of the coniferous and deciduous species studied. Although, the greatest color differences in wet and oven-dried samples of coniferous trees were measured in CW (~15-17 %), it has been found as about 0.7-3 % in TW for deciduous species. Some differences were observed in the anatomical, optical, fiber morphological, and chemical properties of the RW for the studied wood species. Due to its higher lignin content and better physical properties, CW can be used for producing small households and hand tools, ornaments, toys, etc. It will also be appropriate for use in milling and turning work. It is recommended that, because of the lower lignin content and higher polysaccharide ratio, TW should be primarily used for the cellulose, pulp, and paper industries, where high mechanical resistance values are required. Consequently, RW formation causes some physical, chemical, mechanical, anatomical, and optical differences compared to OW in deciduous and coniferous species.

Supercritical CO2 drying of New Zealand red beech to below the fibre saturation point reduces collapse distortion

Supercritical CO2 offers an alternative method of removing wood moisture and reducing cellular collapse compared to traditional drying techniques. The technique has been previously demonstrated for Pinus radiata and Eucalyptus nitens dewatering and was modified in this study for New Zealand red beech (Nothofagus fusca) heartwood, which is notoriously difficult to dry without causing excessive distortion. The technique was also successfully extended to drying below the fibre saturation point. A specific dewatering and drying schedule was developed for N. fusca because of negligible dewatering using a schedule previously designed for wood with an open hydrofluidic network of interconnected vessels. An anatomical assessment confirmed lumen pathways were occluded with tyloses and polyphenol resins. A fluid dynamics assessment concluded that permeability measurements are recommended together with tortuosity and porosity information for improved wood species dewatering characterisation. Using the dewatering and drying schedule, collapse was successfully reduced by 92% for both normalised internal wood area and void collapse when compared to oven-dried samples. The beech specimens took 18 days to reach 17.3% moisture content (MC) but displayed some checking from early dewatering depressurisation, compared to air-dried control specimens which showed no collapse or checking but took 6 months to reach 12% MC. Supercritical CO2 dewatering and drying could be combined with extractives separation, preservative treatment, and mechanical forming of wood in one plant to make a potentially economically viable process with improved energy, environmental and carbon footprints. A techno-economic analysis is suggested to fully compare supercritical drying of wood against conventional drying operations.

Different drying techniques effect on the bioactive properties of rose petals

This study explored the effect of different drying methods (sun, shade, oven) on the total polyphenol content (TPC) using the Folin–Ciocalteu (FC) procedure, total flavonoid content (TFC) using the AlCl3 colorimetric method, volatile organic compounds using GC/MS and the antioxidant properties of the rose petals using the protocol of DPPH assy. The results demonstrated that the drying methods had a significant impact and the highest TPC (34.24 mg gallic acid equivalent (GAE)/ g fresh weight (FW)) and TFC (5.56 mg catechin equivalent (CE)/g FW) were obtained for the oven-dried sample. While, the fresh sample exhibited the lowest TPC (15.6 mg GAE/g FW) and TFC (3.83 mg CE/g FW), respectively. Similarly, the oven-dried sample showed the highest DPPH scavenging activity (60.30 %) and reducing power (absorbance 1.138) among all the samples. Fresh rose sample GC–MS analysis revealed that the there are two major compounds heptacosane 64.56 % and citronellyl propionate 28.35 %. Pentadecyl 2-phenylethyl ester oxalic acid was the second dominant compound in sun and oven-dried rose samples, 18.5 % and 14.79 % respectively.

Fungal composition, quantification of mycotoxins and enzyme activity in processed Solanum tuberosum Linn (Potato) products stored at different relative humidity.

Postharvest loss of potatoes at the peak of harvest is of global concern. This study aimed to determine the quality of stored processed potato products based on fungal composition, mycotoxin contamination and fungal enzyme activity. Potato products from three cultivars (Caruso, Marabel and Nicola) were grouped as peeled or unpeeled, oven- or sun-dried and all samples were in flour form. Samples were incubated separately for six weeks at 25%, 74% and 87% relative humidities (RH) at 25°C. The pH, moisture content, visible deterioration, mycotoxin, fungal identity by DNA sequencing, and enzyme activity were determined. Results of grouped products (based on variety, drying and peeling method) revealed that moisture content increased in the oven-dried samples and the pH value reduced after incubation. About 26% of the products at 87% RH showed visible deterioration, low amounts of fumonisin were detected in fermented potato product and nine fungal genera were identified across the three RH levels. Enzyme activities by Aspergillus niger, Fusarium circinatum and Rhizopus stolonifer isolates were confirmed. RH influenced deterioration and fungal activities in some stored processed potato products. Low levels of fumonisin were detected.

Effect of Different Drying Techniques on the Functionality and Digestibility of Yellow-Fleshed Cassava Flour and Its Performance in Food Application

The impact of different drying techniques on the properties of yellow cassava flour and its food application was investigated in this study. Flour was made from three cultivars of yellow cassava by solar-, hot air oven-, or drum- drying. Their functionality was determined by standard methods, and their digestibility was evaluated in vitro. The flours were used in the preparation of fufu, which was evaluated by sensorial and instrumental methods. The digestibility of drum-dried flours was higher (69.4–79.7%) than solar- (60.4–70.7%) or air oven-dried flours (60.3–70.4%), whereas β-carotene concentration was higher in air oven-dried samples compared to the others. Significant differences ( p &lt; 0.05 ) due to cultivar and/or drying technique were observed in the hydration and pasting properties of the flours. Instrumental texture analysis of fufu made from yellow cassava flours showed both drying technique and cultivar to affect the hardness, adhesiveness, and cohesiveness of the product. Acceptability scores for the fufu ranged from 4 to 6, with a decisive preference for samples produced from drum-dried flours. The study has shown the successful utilization of different drying techniques in the production of flour from yellow cassava variants for the preparation of fufu.

Drying characteristics of grain corn subjected to different drying techniques

Grain corn is one of the most important crops for feed production in Malaysia. Freshly harvested grain corn contains a significant amount of moisture content ranging from 25% to 30% (wet basis), which must be reduced to a safe level through the drying process for storage stability. In view of this, whole grain corn was subjected to various drying techniques to evaluate the drying performance and its quality retention. Grain corn was harvested at an optimum maturity of 110 days after planting and dried in ambient, sun and oven at 40°C. Ambient drying of whole grain corn showed the longest drying time, followed by sun drying and oven drying at 40°C. The time taken to reduce moisture content to less than 12% (wet basis) was observed to be 359 hrs for air-dried samples, 292 hrs for sun-dried samples and 55.5 hrs for oven-dried samples. Mathematical modelling for each drying technique demonstrated that Midili’s equation displayed the best fitting to describe the drying characteristics of air-dried samples of grain corn, while the diffusion approach’s equation was the best mathematical model for sun and oven-dried samples. The concentrations of total carotenoids in the final products for all drying treatments were in the range between 0.290 mg/g to 0.346 mg/g for all drying techniques indicating better stability with low deterioration rates when subjected to low temperature drying.

Effects of pre-test heating temperature on microstructure, chemical and mineralogy of lateritic soil

Pre-test drying methods are known to have a significant impact on the properties of lateritic soils. Nevertheless, there has not been sufficient investigation into the impact of pre-test drying temperature on the mineralogical and microstructural characteristics of lateritic soils, which are particularly sensitive to moisture variation. This work aims to investigate the impact of the temperature used for pre-test drying on the microstructure and mineralogy properties of three lateritic soils from Ado-Ekiti, Southwest Nigeria, which developed over different Precambrian basement complex rocks. Samples of disturbed lateritic soils were collected and tested at their natural moisture content (NMC) as well as at three other states obtained through air-drying and oven-drying at 60 °C and 110 °C. X-ray diffraction and scanning electron microscope (SEM) analyses were performed to explore the mineralogy and microstructural properties of the soils. Results show that the lateritic soils at their NMC consist mainly of kaolinite, quartz, and k-feldspar, while minerals like clinopyroxene, mica, and plagioclase feldspar, hematite are present in minor quantity. The increase in the pre-test drying temperature had no significant impact on the mineralogy or elemental composition of the lateritic soil, possibly due to the fact that the temperature was not sufficiently high to trigger mineral transformation. As the pre-test drying temperature rose, SEM micrographs indicated that the structure of the air-dried and oven-dried soil samples became increasingly aggregated and clumped, particularly when the temperature reached 110 °C. This suggests that the oven-drying process caused particle aggregation, which altered the structure of the lateritic soils and, in turn, affected properties such as plasticity and particle size distribution.

Impact of Drying Process on the Phenolic Profile and Antioxidant Capacity of Raw and Boiled Leaves and Inflorescences of Chenopodium berlandieri ssp. berlandieri.

C. berlandieri ssp. berlandieri (C. berlandieri) is one of the most common members of the group of plants known as quelites, which are dark leafy greens widely consumed in Mexico. This study aimed to evaluate the impact of two drying procedures (oven drying and freeze-drying/lyophilization) on the polyphenolic composition, antioxidant capacity, and proximal chemical analysis of C. berlandieri leaves and inflorescences (raw or boiled). The results indicated that the raw freeze-dried samples had higher amounts (p < 0.05) of total phenolic compounds, total flavonoids, and antioxidant capacity, mainly in the inflorescence. The oven-dried samples showed an increased concentration of polyphenols after boiling, while the lyophilized samples showed a slightly decreased concentration. The drying process was observed to have little impact on the proximal chemical composition. Quantification by UPLC-DAD-ESI-QToF/MS identified up to 23 individual phenolic compounds, with freeze-dried samples showing higher amounts of individual compounds compared with oven-dried. Procyanidin B2 was found exclusively in the inflorescences. The inflorescences have a higher content of phenolic compounds and greater antioxidant capacity than the leaves. Regardless of the drying process, the leaves and inflorescences of C. berlandieri contain an interesting variety of phenolic compounds that may have beneficial effects on health.

Effect of Extraction Methods on the Antioxidant Potential and Cytotoxicity of the Combined Ethanolic Extracts of Daucus carota L., Beta vulgaris L., Phyllanthus emblica L. and Lycopersicon esculentum against Gastric Adenocarcinoma Cells.

Frequent consumption of fruits and vegetables in the daily diet may alleviate the risk of developing chronic diseases. Daucus carota L. (carrot), Beta vulgaris L. (beetroot) Phyllanthus emblica L. (amla), and Lycopersicon esculentum M (tomatoes) are traditionally consumed functional foods that contain a high concentration of antioxidants, ascorbic acid, polyphenols, and numerous phytochemicals. This study assessed how three distinct preparation methods affect the phenolic, flavonoid, carotenoid, and ascorbic acid contents, antioxidant level, and cytotoxicity of the combined fruit extract. The fruit samples were taken in the ratio of carrot (6): beetroot (2): tomato (1.5): amla (0.5) and processed into a lyophilized slurry (LS) extract, lyophilized juice (LJ) extract, and hot-air oven-dried (HAO) extract samples. The sample extracts were assessed for their phytoconstituent concentrations and antioxidant and cytotoxic potential. The total phenolic content in LS, LJ, and HAO extracts was 171.20 ± 0.02, 120.73 ± 0.02, and 72.05 ± 0.01 mg gallic acid equivalent/100 g, respectively and the total flavonoid content was 23.635 ± 0.003, 20.754 ± 0.005, and 18.635 ± 0.005 mg quercetin equivalent/100 g, respectively. Similarly, total ascorbic acid content, carotenoids, and antioxidant potential were higher in the LS and LJ extracts than in HAO. Overall, the LS extract had a substantially higher concentration of phytochemicals and antioxidants, as well as higher cytotoxic potential, compared to the LJ and HAO extracts. The LS extract was tested in the MKN-45 human gastric cancer cell line to demonstrate its effective antioxidant potential and cytotoxicity. Hence, lyophilization (freezing) based techniques are more effective than heat-based techniques in preserving the phytoconstituents and their antioxidant and cytotoxic potential.