Oil-treated Samples Research Articles

Dimensional stability and mechanical strength of thermally modified giant bamboo [Dendrocalamus asper (Schult.) Backer] using steam and oil

Various thermal modification (TM) treatments using different media have been commercialized, including the commonly practiced TM via steam and hot oil using vegetable or mineral oils. To expand the range of oil treatment mediums, this study explored the use of spent cooking oil (used oil from food frying in restaurants), which was centrally collected by a certified hauler and treater of this waste liquid. The effects on the dimensional stability and mechanical strength of giant bamboo [Dendrocalamus asper (Schult.) Backer] poles subjected to 175°C and 200°C for 30 min and 60 min in steam and oil, respectively were determined. The data were analyzed using a factorial experiment in a completely randomized design with TM treatments, temperature, duration, and presence of nodes as factors.Results revealed significantly improved dimensional stability in modified bamboo as indicated by reduced moisture content, dimensional shrinkage/swelling, and water loss/absorption at higher temperatures. While treatment duration moderately affected dimensional stability, oil-treated samples exhibited greater enhancement.In terms of mechanical strength, bamboo treated at 175°C exhibited enhanced flexural (modulus of rupture or MOR, and modulus of elasticity or MOE) and compressive strength (CS). However, treatments at 200°C led to marked reductions in these properties. Node presence generally weakened bamboo, except for CS. Oil-treated samples demonstrated superior mechanical strength, although there was a slight reduction in MOR with extended exposure.In conclusion, steam and oil-based TM improve the dimensional stability and mechanical strength of giant bamboo at 175°C. For optimal properties, a 30-min treatment is recommended. This research underscores the viability of spent cooking oil in enhancing bamboo's physico-mechanical attributes, contributing to sustainable applications.

Dried Herbs as an Easy-to-Use and Cost-Effective Alternative to Essential Oils to Extend the Shelf Life of Sheep Lump Cheese.

The objective of this research was to assess the effectiveness of three specific dried herbs (rosemary, thyme, and oregano) in combating microbial spoilage in sheep lump cheese. This was achieved by comparing them with a control group and cheeses treated with corresponding 1% essential oils (Rosmarinus officinalis, Origanum vulgare, Thymus vulgaris). All cheese samples were vacuum-sealed and stored at 4 °C for 15 days. Analysis of total viable counts of viable bacteria (TVC), coliform bacteria (CB), lactic acid bacteria (LAB), and microscopic filamentous fungi (MFF) was conducted on days 0, 5, 10, and 15. The results revealed that, at the end of the storage period, dried oregano-treated samples exhibited the lowest TVC count (5.80 log CFU/g), while dried rosemary-treated samples showed the lowest CB count (3.27 log CFU/g). Moreover, the lowest MFF count (2.40 log CFU/g) was observed in oregano essential oil-treated samples. Additionally, dried oregano-treated samples displayed the highest LAB count (4.49 log CFU/g) at the experiment's conclusion. Furthermore, microorganism identification from sheep cheese was performed using MALDI-TOF MS Biotyper technology, revealing that the most frequently isolated bacteria were Citrobacter braakii and Hafnia alvei (Enterobacteriaceae family), along with Lacticaseibacillus paracasei (Lactobacillaceae family). In summary, all the natural substances examined exhibited inhibitory effects against the studied microorganisms, with oregano essential oil and dried oregano demonstrating the strongest inhibitory effects. This supports their potential use as cost-effective natural preservatives to extend the shelf life of sheep lump cheese.

Effects of hot-cold oil treatment on biological resistance and physical properties of Brutia pine sapwood

This study investigated the physical properties of hot-cold oil-treated Brutia pine sapwood (Pinus brutia) and its biological resistance against wood-decay fungi. Weight percent gain, density, water absorption, and volumetric shrinking were chosen as the physical properties of the wood. White rot (Trametes versicolor) and brown rot (Neolentinus lepideus) were selected as the wood-decay fungi. Two different temperatures and two different time intervals were determined for the hot-cold oil treatment. Castor oil (Ricinus communis), flaxseed oil (Oleum linii), and a mixture of the two were used as the treatment oils (the medium of the hot-cold treatment). The results showed that the physical properties of the hot-cold oil-treated samples improved significantly compared to those of the control samples. In addition, after exposure to the decay fungi, the mass loss of the hot-cold flaxseed oil-treated samples decreased significantly more than in either the untreated samples or those treated with the other oils. There was a significant increase in the water repellent effectiveness and dimensional stability of the Brutia pine sapwood with all hot-cold oil treatments, but the hot-cold castor oil treatment appeared to have had no effect on decay resistance. A hot-cold oil treatment using flaxseed oil or a mixture including it could be a suitable method for improvement of the water repellent effectiveness, dimensional stability, and decay resistance of Brutia pine sapwood, as they both reduced the water uptake and the mass loss against the wood-decay fungi compared to the results of the control samples

Effect of Lettuce, Marjoram and Cumin Essential Oils on the Quality and Shelf Life of Minced Meat during Refrigerated Storage

Essential oils (EOs) can improve the shelf life of foods due to its antimicrobial and antioxidant properties in addition to being natural flavoring agents. Nonetheless, very little EOs approaches depending on EOs utilization have been introduced by the food industry until now. In this study, the effect of certain EOs such as lettuce (Lactuca sativa L.), marjoram (Origanum majorana L.) and cumin (Cuminum cyminum) at a concentration (2%) on the chemical, bacterial quality and sensory properties of minced meat was investigated, as well as their capacity to extend the shelf life of minced meat during cold storage at 4°C for 12 days. The obtained results showed that oil-treated samples indicated significantly lowering values (p < 0.05) for chemical, bacterial assessment, and improving sensory properties than untreated (control) ones. In addition, cumin and marjoram EOs had the greatest impact followed by lettuce oil. Therefore, the studied EOs could be used as an alternative option to synthetic chemical substances to eliminate the spoilage bacteria, prevent lipid oxidation, and consequently extend the shelf life of minced meat.

Effect of ginger oil on tenderization of spent goat meat

To tenderize tough spent goat meat, an aqueous emulsion of ginger oil (0.10, 0.25 and 0.50%) was added and marinated for 24 h at refrigeration temperature. The samples were analyzed for physico-chemical characteristics, texture profile and sensory evaluation. With the addition of ginger oil, sarcomere length increased, muscle fibre diameter was altered and the other physicochemical characteristics did not show any significant difference. The shear force value of control was 7.64 kg/cm2 and that of the ginger oil (0.25 and 0.50%) treated sample was significantly (P<0.05) reduced to 5.73 and 5.68 kg/cm2. Non-significant variation was observed by addition of ginger oil in sensory and texture profile characteristics of spent goat meat. The overall acceptability scores of control and 0.10% ginger oil-treated samples were 6.09±0.25 and 6.32±0.18, respectively. It was concluded that the addition of ginger oil at 0.10% level could be used to tenderize the spent goat meat without affecting the physico-chemical and sensory characteristics.

Control of Penicillium sp. on the Surface of Italian Salami Using Essential Oils.

The goal of this study is to evaluate the in vitro effects of rosemary, salvia, oregano and clove oils at volume fractions of 1000, 750, 500, 250, 100, 50, 26, 10 and 5 µL/mL (100, 75, 50, 25, 10, 5, 3, 1 and 0.5%) on the growth of contaminating fungi in salami. The in vitro effect of the oils against fungal growth was indicated by zones of inhibition. Rosemary oil showed an inhibition zone of 9.6 mm only at the maximal volume fraction (1000 µL/mL). Salvia oil showed inhibition zones of 12.2, 11.2 and 10.5 mm only at the three highest fractions tested. Based on the inhibition zones, clove oil at 125 and 250 µL/mL, oregano oil at 250 and 500 µL/mL and a mixture (1:1 by volume) of the two oils at 100 µL/mL were selected to be applied to the surface of salamis. A significant reduction of fungal growth in all of the oil-treated samples was confirmed by visual inspection. A sensory analysis revealed that the samples treated with 125 µL/mL of clove oil or 100 µL/mL of a mixture of oregano and clove oil showed no significant flavour differences compared with the control. Carvacrol and eugenol were the principal compounds in oregano and clove oils, respectively, and were most likely responsible for the antifungal activity.

Comparative analysis of bacterial community-metagenomics in coastal Gulf of Mexico sediment microcosms following exposure to Macondo oil (MC252).

The indigenous bacterial communities in sediment microcosms from Dauphin Island (DI), Petit Bois Island (PB) and Perdido Pass (PP) of the coastal Gulf of Mexico were compared following treatment with Macondo oil (MC252) using pyrosequencing and culture-based approaches. After quality-based trimming, 28,991 partial 16S rRNA sequence reads were analyzed by rarefaction, confirming that analyses of bacterial communities were saturated with respect to species diversity. Changes in the relative abundances of Proteobacteria, Bacteroidetes and Firmicutes played an important role in structuring bacterial communities in oil-treated sediments. Proteobacteria were dominant in oil-treated samples, whereas Firmicutes and Bacteroidetes were either the second or the third most abundant taxa. Tenericutes, members of which are known for oil biodegradation, were detected shortly after treatment, and continued to increase in DI and PP sediments. Multivariate statistical analyses (ADONIS) revealed significant dissimilarity of bacterial communities between oil-treated and untreated samples and among locations. In addition, a similarity percentage analysis showed the contribution of each species to the contrast between untreated and oil-treated samples. PCR amplification using DNA from pure cultures of Exiguobacterium, Pseudoalteromonas, Halomonas and Dyadobacter, isolated from oil-treated microcosm sediments, produced amplicons similar to polycyclic aromatic hydrocarbon-degrading genes. In the context of the 2010 Macondo blowout, the results from our study demonstrated that the indigenous bacterial communities in coastal Gulf of Mexico sediment microcosms responded to the MC252 oil with altered community structure and species composition. The rapid proliferation of hydrocarbonoclastic bacteria suggests their involvement in the degradation of the spilt oil in the Gulf of Mexico ecosystem.

Study on antimicrobial potential of neem oil nanoemulsion against Pseudomonas aeruginosa infection in Labeo rohita

Presence of several biochemical constituents in neem makes it an efficient antimicrobial agent for pathogenic diseases. The current investigation was aimed to assess the therapeutic potential of neem nanoemulsion as a control measure for Pseudomonas aeruginosa infection in freshwater fish Labeo rohita. The median lethal concentration (LC50) for the neem oil and neem nanoemulsion was 73.9 and 160.3 mg/L, respectively. The biomarker enzymes of treated fish tissues showed a significant difference in the level of glutathione reductase, catalase, and lipid peroxidation in neem oil-treated samples than in neem nanoemulsion-treated samples at P<0.05. The results were corroborative with histopathology and ultrastructural analysis. The bacterial infection of P. aeruginosa treated using neem nanoemulsion was more effective in both in vitro and in vivo methods. Present findings suggest that neem-based nanoemulsion has negligible toxicity to Rohu fishes. This makes neem-based nanoemulsion as an efficient therapeutic agent against P. aeruginosa infection, leading to its possible usage in the aquaculture industry.

Evaluation of preservative distribution in thermally modified European aspen and birch boards using computed tomography and scanning electron microscopy

The aim of this experiment was to impregnate thermally modified wood using an easy and cost-effective method. Industrially processed thermally modified European aspen (Populus tremula L.) and birch (Betula pubescens Ehrh.) were collected and secondarily treated at the laboratory scale with the preservatives tung oil, pine tar and Elit Traskydd (Beckers) using a simple and effective method. Preservative uptake and distribution in sample boards were evaluated using computed tomography (CT) and scanning electron microscopy (SEM) techniques. Preservative uptake and treatability in terms of void volume filled were found the highest in Beckers and the lowest in tung oil-treated samples. Thermally modified samples had lower treatability than their counterpart control samples. More structural changes after thermal modification, especially in birch, significantly reduced the preservative uptake and distribution. The differences of preservatives uptake near the end grain were high and then decreased near the mid position of the samples length as compared with similar type of wood sample. Non-destructive evaluation by CT scanning provided a very useful method to locate the preservative gradients throughout the sample length. SEM analysis enabled the visualization of the preservative deposits in wood cells at the microstructural level.

Protective effect of essential oils on the shelf life of smoked and vacuum packed rainbow trout (Oncorhynchus mykiss W.1792) fillets.

This study was investigated the effects of some oils on chemical, microbiological and sensory quality in vacuum packed smoked rainbow trout (Oncorhynchus mykiss W.1792) fillets. Acceptability scores for appearance, taste and odour of untreated and treated smoked trout decreased with storage time. The limit of sensory acceptance was reached after 56days for the untreated samples, after 84days for with rosemary and thyme oil-treated samples after 98days for with sage oil-treated and after 112days for with clove oil-treated samples. Significant differences were not found between groups as microbiological (p > 0.05). However, significant differences were found both among groups and during the storage in term of TBA (thiobarbituric acid) and PV (peroxide value), FFA (free fatty acid) values (p < 0.05). Essential oils as natural antioxidant can be used in conjunction with vacuum packed to enhance hot smoked fish quality.

Effectiveness of selected preservatives in protecting Ugandan grown Eucalyptus grandis wood against termite attack

Termites are one of the major wood destroying agents in the tropics and with the increasing rateof deforestation, there is a need to protect wood from biodegradation in order to extend its servicelife. In this study the incidence and severity of termite attack on Eucalyptus grandis sapwood treatedwith CCA, used engine oil and neem extract were investigated. Sixty samples (20 × 20 × 300mm)were prepared from the sapwood at mid-height of the tree of E. grandis and air seasoned for twoweeks then treated with the preservatives. An area of 20m by 20m in a pine plantation and 15 plotsof 1m by 1m were selected at random. Four samples, one from each treatment, were placed at thecorners of the selected plots.Inspection and evaluation of stakes was made by visual assessments after every 30 days forany sign of termite attack for a period of 8 months. The specimens were removed from the ground,damage assessed and returned to the ground. After 4 weeks all the untreated wood samples hadbeen attacked, neem extract treated wood samples were attacked after 17 weeks and used engine oiltreated samples after 30 weeks. None of the CCA treated wood samples were attacked by the endof study period. Chi square analysis showed a high association between treatment and incidenceas well as between treatment and severity. It was recommended that further research be carried outon neem extract using different concentrations.

The Effect of Thyme and Garlic Oil on the Preservation of Vacuum-Packaged Hot Smoked Rainbow Trout (Oncorhynchus mykiss)

Quality and shelf life of filleted hot smoked rainbow trout packaged in vacuum packaging (untreated) and with thyme oil (TO), and garlic oil (GO)-treated, after vacuum-packaged (VP) conditions stored at 2 °C, were investigated by measurement of microbiological, sensory and physicochemical analyses. Acceptability scores for appearance, odour, taste and texture of untreated and treated smoked trout decreased with storage time. The limit of sensory acceptance was reached after 5 weeks for the untreated samples, after 7 weeks for with thyme oil-treated samples (TO + VP) and after 6 weeks for with garlic oil-treated (GO + VP) samples. Total viable count evaluated that thyme oil- and garlic oil-treated vacuum-packaged samples had good results up to 7 weeks compared with 5 weeks in control vacuum packs. Psychrotrophic counts for untreated and treated samples exceeded 6 log cfu/g after 5 and 6 weeks of cold storage, respectively. Treated samples presented the lowest lactic acid bacteria counts. Total volatile basic nitrogen and trimethylamine nitrogen values gave acceptable results for up to 5 weeks for the untreated samples, 7 weeks for thyme- and garlic oil-treated samples. Treated with thyme oil samples presented the lowest thiobarbituric acid index values. The results obtained from this study showed that the shelf life of hot smoked rainbow trout stored in cold storage (2 °C), as determined by overall acceptability of all data, is 5 weeks for vacuum-packaged samples and 7 weeks for thyme- and garlic oil-treated vacuum-packaged smoked fish.

Effect of oil films on moisture vapor absorption on human hair

In this paper sorption and desorption of water vapor on hair fibers treated with various oils is investigated, using a dynamic vapor sorption (DVS) apparatus. Results show lower "equilibrium" sorption of moisture for various oil-treated samples compared to the untreated sample. Coconut oil-treated hair had a higher regain than mineral oil-treated hair. Although treating the hair samples with oil reduced moisture pickup, a considerable amount of moisture vapor was still able to penetrate into hair fibers. Calculated hysteresis plots show that the samples treated with different oils have slightly higher moisture retention at low relative humidities compared to that of the untreated sample, which suggests a beneficial effect. The calculated moisture diffusion coefficients for oil-treated samples were much lower compared to the untreated hair fibers, suggesting that surface oil films and penetrated oil molecules form a diffusion barrier. A moisture diffusion model is discussed in terms of the possible role of fiber swelling on restrictive narrowing of the cell membrane complexes (CMCs), which form the diffusion pathways in the fiber. The effect of film thickness on moisture absorption and the reverting of the sorption isotherm to that of the untreated hair after removal of the oil film shows that oil film is the main resistance to moisture diffusion. The lowering of the diffusion coefficient of water vapor by oil films will slow the loss of moisture, an effect similar to "moisturization" of hair.