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1.
Heliyon ; 10(7): e28383, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38601676

RESUMO

This article presents a novel study of spherical fuzzy sets (SFSs), a more comprehensive framework of intuitionistic fuzzy sets and picture fuzzy sets. The SFS allows the decision-makers (DMs) to cope with complicated and insufficient information during the aggregation process. The Heronian mean (HrM) model theory is also utilized to express correlation among different input arguments or characteristics. Recently, the theory of Aczel Alsina triangular norms gained a lot of attention from various research scholars and has many capabilities to provide smooth approximations during decision analysis. In this article, we developed some appropriate operations of Aczel Alsina t-norms and t-conorms in light of spherical fuzzy (SF) information. We develop new mathematical ways to look at SF data to keep clarity and sufficient information. These are the SF Aczel Alsina Heronian mean (SFAAHrM) and SF Aczel Alsina weighted Heronian mean (SFAAWHrM) operators. Furthermore, we also present a list of new strategies based on Aczel Alsina operations, such as SF Aczel Alsina geometric Heronian mean (SFAAGHrM) and SF Aczel Alsina weighted geometric Heronian mean (SFAAWGHrM) operators. Some notable properties are also characterized to show the validity and effectiveness of our derived mathematical approaches. Considering our derived strategies, an algorithm for the multiple attribute decision-making (MADM) problem is established to resolve complicated real-life applications. A numerical example presents the compatibility of derived approaches and provides a solid mechanism to improve the performance of educational institutes. A comparison technique is also demonstrated to show the applicability and consistency of diagnosed approaches by contrasting the findings of pioneered approaches with existing methodologies.

2.
Foods ; 11(22)2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36429289

RESUMO

Polyphenols in pigmented cereals are believed to enhance health outcomes through their antioxidant properties. This study aimed to characterise polyphenols from Hordeum vulgare (purple barley), Triticum turgidum (purple wheat) and Triticum aestivum (blue wheat) in order to evaluate their bioaccessibility and antioxidant activity. An ultra-high performance liquid chromatography mass spectrometry coupled with an online 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) system was used to identify the polyphenols and quantify their relative antioxidant levels. Simulated gastrointestinal digestion of the cereals allowed for the assessment of polyphenol bioaccessibility using benchtop assays. Between cereals, the bioaccessible phenolic content was similar following digestion, but the antioxidant activity was significantly different (purple barley > purple wheat > blue wheat; p < 0.01). Among the polyphenols identified, flavan-3-ols and anthocyanins were the least bioaccessible whereas flavones were the most bioaccessible after digestion. This study demonstrated that these pigmented cereal varieties are sources of bioaccessible polyphenols with antioxidant activity. These findings may aid in utilising these pigmented grains for the future design and development of novel functional food products with enhanced health properties.

3.
Animals (Basel) ; 12(19)2022 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-36230450

RESUMO

Legume crops and pastures have a high economic value in Australia. However, legume species commonly used for grazing enterprises have been identified to produce high concentrations of phytoestrogens. These compounds are heterocyclic phenolic, and are similar in structure to the mammalian estrogen, 17ß-estradiol. The biological activity of the various phytoestrogen types; isoflavones, lignans and coumestans, are species-specific, although at concentrations of 25 mg/kg of dry matter each of the phytoestrogen types affect reproductive functions in grazing livestock. The impacts upon fertility in grazing livestock such as cattle and sheep, vary greatly over length of exposure time, age and health of animal and the stress stimuli the plant is exposed to. More recently, research into the other effects that phytoestrogens may have upon metabolism, immune capacity and growth and performance of grazing livestock has been conducted. Potential new benefits for using these phytoestrogens, such as daidzein and genistein, have been identified by observing the stimulation of production in lymphocytes and other antibody cells. Numerous isoflavones have also been recognized to promote protein synthesis, increase the lean meat ratio, and increase weight gain in cattle and sheep. In Australia, the high economic value of legumes as pasture crops in sheep and cattle production enterprises requires proactive management strategies to mitigate risk associated with potential loss of fertility associated with inclusion of pasture legumes as forages for grazing livestock.

4.
Meat Sci ; 186: 108729, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35016106

RESUMO

The aim of the study was to investigate quality and shelf life of beef meat cooked under sous vide conditions then extended refrigerated storage for 10 weeks. Biceps femoris (n = 6) from six to seven year old cows were treated with 2 g/L ginger powder (GP) containing zingibain or control (no injection) and were then cooked in sous vide conditions at 65 °C for 1 h or 8 h. Cooked samples were evaluated for physicochemical (pH, total water content, cooking loss, Warner-Bratzler shear force (WBSF), texture profile analysis (TPA), L*, a*, b* properties and thiobarbituric acid reactive substance (TBARS)), microstructure (scanning electron microscopy) and microbiological (Brochothrix thermospacta, Clostridium perfringens, Lactic acid bacteria, Listeria monocytogenes, Salmonella spp, and yeasts and moulds) quality after vacuum packing, cooking, then refrigerated storage at 4 °C for 0, 2, 4, 8 or 10 weeks. Physicochemical parameters were improved by GP treatment (P < 0.05) while there was no effect of storage time on WBSF, TPA or microstructure. The microbial quality of sous vide cooked meat in refrigerated storage appeared to be four weeks and oxidation shelf life of the cooked meat was found to be two weeks under refrigerated storage.


Assuntos
Músculos Isquiossurais , Zingiber officinale , Animais , Bovinos , Culinária , Feminino , Carne/análise , Pós
5.
Food Chem ; 372: 131173, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34601424

RESUMO

The variation of proximate compositions, amino acids, carotenoids, chlorophyll, and total cyanide contents in cassava leaves was studied to identify the most suitable leaves for human consumption. The cassava leaves from 4 cultivars were analysed at 3 leaf positions as well as at 2 plant ages. The leaves of 'Rayong 5' cultivar from the middle position at 6 months after planting contained the highest crude protein, amino acids, carotenoids, and chlorophyll. The total cyanide content was high and therefore, an effective detoxification method is needed. Protein from the cassava leaves was rich in glutamine, aspartic acid, and leucine, but low in methionine and cysteine. Additionally, cassava leaves were found to be a rich source of carotenoids and chlorophyll. This study provided the evidences that cassava leaves can be an alternative source as protein supplement and for carotenoids and chlorophyll extraction and paves the way to valorise this abundant agricultural by-product.


Assuntos
Manihot , Carotenoides/análise , Clorofila , Cianetos , Humanos , Folhas de Planta/química , Tailândia
6.
Plants (Basel) ; 10(8)2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34451550

RESUMO

Annual ryegrass (Lolium rigidum Gaud.), traditionally utilised as a pasture species, has become the most problematic and difficult-to-control weed across grain production regions in Australia. Annual ryegrass has been favoured by the adoption of conservation tillage systems due to its genetic diversity, prolific seed production, widespread dispersal, flexible germination requirements and competitive growth habit. The widespread evolution of herbicide resistance in annual ryegrass has made its management within these systems extremely difficult. The negative impacts of this weed on grain production systems result in annual revenue losses exceeding $93 million (AUD) for Australian grain growers. No single method of management provides effective and enduring control hence the need of integrated weed management programs is widely accepted and practiced in Australian cropping. Although annual ryegrass is an extensively researched weed, a comprehensive review of the biology and management of this weed in conservation cropping systems has not been conducted. This review presents an up-to-date account of knowledge on the biology, ecology and management of annual ryegrass in an Australian context. This comprehensive account provides pragmatic information for further research and suitable management of annual ryegrass.

7.
Metabolites ; 11(8)2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34436490

RESUMO

Phytoestrogens are plant-produced bioactive secondary metabolites known to play an integral role in plant defense that frequently accumulate in times of stress and/or microbial infection. Phytoestrogens typically belong to two distinct chemical classes; flavonoids (isoflavones) and non-flavonoids (lignans and coumestans). Upon consumption by livestock, high concentrations of phytoestrogens can cause long-term disruption in reproduction due to structural similarities with mammalian estrogens and their tendency to bind estrogen receptors. Wide variation in phytoestrogen concentration has been reported in pasture legumes and corresponding silage or hay. Lucerne is a common perennial pasture legume in temperate climates, but information on phytoestrogen production or accumulation in grazing livestock is currently limited. Therefore, metabolic profiling using UHPLC-MS-QToF was performed to identify and quantitate key phytoestrogens in both fresh and dried lucerne fodder from replicated field or controlled glasshouse environments. Phytoestrogens were also profiled in the blood plasma of Angus cattle grazing field-grown lucerne. Results revealed that phytoestrogens varied quantitatively and qualitatively among selected lucerne cultivars grown under glasshouse conditions. Fresh lucerne samples contained higher concentrations of coumestans and other phytoestrogenic isoflavones than did dried samples for all cultivars profiled, with several exceeding desirable threshold levels for grazing cattle. Coumestans and isoflavones profiled in plasma of Angus heifers grazing lucerne increased significantly over a 21-day sampling period following experimental initiation. Currently, threshold concentrations for phytoestrogens in plasma are unreported. However, total phytoestrogen concentration exceeded 300 mg·kg-1 in fresh and 180 mg·kg-1 in dried samples of selected cultivars, suggesting that certain genotypes may upregulate phytoestrogen production, while others may prove suitable sources of fodder for grazing livestock.

8.
Foods ; 10(8)2021 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-34441490

RESUMO

Cassava plays a major role in improving food security and reducing malnutrition. The purpose of this study was to evaluate the influence of mechanical pressing coupled with ultrafiltration (UF) on the quality of different fractions of cassava leaves. Cassava leaves harvested from the greenhouse at the University of Hohenheim were passed through a mechanical screw press to extract the juice and separate the press cake. The juice was centrifuged and filtered to separate the sediment and clear supernatant. The clear supernatant was filtered using a 10 kDa UF system. The nutritional contents of the different fractions were analyzed at each processing step. The total phenolic content was significantly lower in the press cake that had a higher fiber and ash content. The juice and sediment fractions had higher crude protein and total phenolic content. Processing did not negatively affect the concentrations of essential amino acids except for tryptophan in the juice fraction. Non-protein nitrogen was mainly present in the UF permeate, illustrating the potential of UF for upgrading soluble protein fractions. The results indicated that the different fractions during processing could be a possible source of protein for food, feed (juice, sediment, and retentate), or fiber (press cake) for ruminant feed.

9.
Foods ; 10(8)2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34441712

RESUMO

This study aimed to evaluate the sensory and physical characteristics of zingibain-injected meat combined with sous vide cooking. M. biceps femoris (BF; n = 12) acquired from 6-7 year old Angus cows were cooked using the sous vide method at 65 °C, for 8 h or 12 h, either with ginger powder (GP) injected in a 2 g/L solution in water (treatment) or un-injected (control). The sensory attributes included flavour, juiciness, tenderness, and physicochemical characteristics were Warner-Bratzler shear (WBSF), hardness, total water content (TWC), cooking loss (CL) and collagen content. A significant improvement in tenderness with injection treatment and cooking time was observed, as evaluated through trained sensory panellists, and reduced WBSF and hardness (p < 0.05 for all). The flavour of the meat was not affected by injection treatment or cooking time (p > 0.05), but juiciness and TWC were reduced with longer cooking times (p < 0.01 for both). Soluble collagen increased with injection treatment and cooking time (both p < 0.05). Moderate to high correlations were found between sensory and physical measurements for tenderness and juiciness. The longer cooking time (12 h) with GP injection treatment caused over tenderization of the meat. The soft texture associated with over-tenderization may be suitable for some specialised consumer markets, for instance, the elderly population with chewing difficulties. Improving the eating quality of low-quality meat from old animals through sous vide cooking and the use of ginger proteases may increase the acceptability of lower value beef, potentially enhancing the commercial value of carcasses typically produced in the beef industry.

10.
Data Brief ; 37: 107192, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34150963

RESUMO

Freshly harvested cassava has a tendency to deteriorate rapidly in its physiological properties after harvest. Therefore, cassava is often processed using a number of unit operations in order to derive a stable, storable product of acceptable eating quality. Among the unit operations employed, drying is considered as one of the oldest and most important process in arresting deterioration of cassava. In recent times, more researchers are considering foam mat drying as a drying technique for tuber or root crops, although the technique is used, ideally, for fruit juices and dairy. Cassava foam production from white and yellow cassava varieties has been optimized in our previous work [1]. Our data were procured from experimentally measuring mass of cassava foams of white and yellow cassava varieties dried at different temperatures (50, 65, 80 °C) and foam thicknesses (6, 8, 10 mm) over regular drying intervals until no considerable mass change was observed. The mass measurements are the primary datasets used in determination of secondary datasets presented here as moisture removal ratio (MR), effective moisture diffusivity (Deff), and drying rate (DR). The MR data were fitted to four thin-layer drying models (Henderson-Pabis, Page, Newton, Two-term), and Page model described the experimental drying data best. The Page model coefficients were analyzed by multiple linear regression (MLR) analysis to show how they are influenced by the drying variables. Drying rate was also fitted by Rational model to fit the DR data and to reflect the two falling rates found. Statistical accuracy and significance were calculated as coefficient of determination (R2), root mean square error (RMSE) and Chi square (χ2) and an analysis of variance (ANOVA). Data obtained here are useful as primary data in process and dryer designs and processing of cassava in the cassava industry.

11.
Plant Methods ; 17(1): 10, 2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-33499873

RESUMO

BACKGROUND: Hypericum is an important genus in the family Hypericaceae, which includes 484 species. This genus has been grown in temperate regions and used for treating wounds, eczema and burns. The aim of this study was to predict the content of hypericin in Hypericum perforatum in varied ecological and phenological conditions of habitat using artificial neural network techniques [MLP (Multi-Layer Perceptron), RBF (Radial Basis Function) and SVM (Support Vector Machine)]. RESULTS: According to the results, the MLP model (R2 = 0.87) had an advantage over RBF (R2 = 0.8) and SVM (R2 = 0.54) models and it was relatively accurate in predicting hypericin content in H. perforatum based on the ecological conditions of site including soil types, its characteristics and plant phenological stages of habitat. The results of sensitivity analysis revealed that phenological stages, hill aspects, total nitrogen, altitude and organic carbon are the most influential factors that have an integral effect on the content of hypericin. CONCLUSIONS: The designed graphical user interface will help pharmacognosist, manufacturers and producers of medicinal plants and so on to run the MLP model on new data to easily discover the content of hypericin in H. perforatum by entering ecological conditions of site, soil characteristics and plant phenological stages.

12.
Molecules ; 25(22)2020 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-33218167

RESUMO

Mango has been described as a valuable source of nutrients and enzymes that are beneficial to human health. Drying at different temperatures not only affects the nutritional properties but can also contribute to the degradation of valuable enzymes in dried fruit. The novelty of this paper is to investigate the quality of hot air dried mango in terms of activity retention of the heat-sensitive enzymes (HSE). For this, HSE was first screened in fresh mango flesh of the variety Samar Bahisht (SB) Chaunsa. Later, the combined effect of different drying temperatures (40 °C, 50 °C, 60 °C, 70 °C, and 80 °C) and air velocities (1.0 ms-1 and 1.4 ms-1) on the activity retention of HSE in dried mango slices of the varieties Sindri, SB Chaunsa, and Tommy Atkins were investigated. The results showed that the drying temperature had a significant impact on the degradation of HSE, while at the same time some influence of the air velocity was also observed. Drying at 40 °C and an air velocity of 1.4 ms-1 retained more HSE compared to those samples dried at higher temperatures. The least retention of HSE was found in samples dried at 80 °C.


Assuntos
Dessecação , Temperatura Alta , Mangifera/enzimologia , Proteólise , Umidade , Cinética
13.
Food Sci Nutr ; 8(7): 3089-3098, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32724573

RESUMO

Cassava is grown because of its starchy roots, but the leaves being rich in protein are mostly underutilized. For protein recovery, mechanical juice extraction from cassava leaves and the extraction process was evaluated using computational fluid dynamics (CFD) simulation. The influence of input variables such as nozzle diameter and rotational speed of the screw was investigated in relation to process efficiency. The highest green juice extraction yield (81.0%) from cassava leaves and dry matter of press cake (61.3%) were achieved by using 4 mm nozzle diameter and 18 rpm screw speed. The protein content of the cassava leaves, press cake, juice sediment, and juice supernatant was found to be 31.5%, 27.7%, 26.2%, and 12.4%, respectively. The crude protein, cellulose, hemicellulose, lignin, and total phenolic content mainly accumulated in the press cake. The screw pressing concentrated the amino acids in the press cake and the juice sediment.

14.
Toxins (Basel) ; 12(7)2020 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-32664345

RESUMO

Parthenium weed (Parthenium hysterophorus L.) is an invasive plant species in around 50 countries and a 'Weed of National Significance' in Australia. This study investigated the relative toxicity of the leaf, shoot and root extracts of two geographically separate and morphologically distinct biotypes of parthenium weed in Queensland, Australia. Parthenium weed exhibited higher phytotoxic, cytotoxic and photocytotoxic activity in leaf tissue extracts in contrast to shoot and root. The germination and seedling growth of a dicot species (garden cress) were inhibited more than those of a monocot species (annual ryegrass) using a phytotoxicity bioassay. The cytotoxicity of leaf extracts was assessed in a mouse fibroblast cell suspension assay and increased under high ultraviolet A(UV-A) radiation. A major secondary metabolite, parthenin, was found in abundance in leaf extracts and was positively correlated with cytotoxicity but not with photocytotoxicity or phytotoxicity. Ambrosin and chlorogenic acid were also detected and were positively correlated with germination inhibition and the inhibition of radicle elongation, respectively. In addition, other currently unidentified compounds in the leaf extracts were positively correlated with phytotoxicity, cytotoxicity and photocytotoxicity with two to three molecules strongly correlated in each case. Both parthenium weed biotypes investigated did not differ with respect to their relative toxicity, despite their reported differences in invasive potential in the field. This suggests that secondary chemistry plays a limited role in their invasion success.


Assuntos
Asteraceae/toxicidade , Metaboloma , Metabolômica , Extratos Vegetais/toxicidade , Plantas Daninhas/toxicidade , Animais , Asteraceae/crescimento & desenvolvimento , Asteraceae/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Fibroblastos/efeitos dos fármacos , Fibroblastos/patologia , Germinação/efeitos dos fármacos , Camundongos , Células NIH 3T3 , Partenogênese , Extratos Vegetais/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/toxicidade , Raízes de Plantas/metabolismo , Raízes de Plantas/toxicidade , Brotos de Planta/metabolismo , Brotos de Planta/toxicidade , Plantas Daninhas/crescimento & desenvolvimento , Plantas Daninhas/metabolismo , Queensland , Metabolismo Secundário
15.
Metabolites ; 10(7)2020 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-32605241

RESUMO

Annual legumes from the Mediterranean region are receiving attention in Australia as alternatives to traditional pasture species. The current study employed novel metabolic profiling approaches to quantify key secondary metabolites including phytoestrogens to better understand their biosynthetic regulation in a range of field-grown annual pasture legumes. In addition, total polyphenol and proanthocyanidins were quantified using Folin-Ciocalteu and vanillin assays, respectively. Metabolic profiling coupled with biochemical assay results demonstrated marked differences in the abundance of coumestans, flavonoids, polyphenols, and proanthocyanidins in annual pasture legume species. Genetically related pasture legumes segregated similarly from a chemotaxonomic perspective. A strong and positive association was observed between the concentration of phytoestrogens and upregulation of the flavonoid biosynthetic pathway in annual pasture legumes. Our findings suggest that evolutionary differences in metabolic dynamics and biosynthetic regulation of secondary metabolites have logically occurred over time in various species of annual pasture legumes resulting in enhanced plant defense.

16.
J Food Sci Technol ; 56(9): 4251-4265, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31477996

RESUMO

In recent times, the cultivation, processing and consumption of biofortified yellow-flesh cassava is of significant interest to breeders and food processors due to its relatively high pro-vitamin-A content, compared to the conventional white-flesh cassava. In light of this, osmotic dehydration (OD) kinetics of a recently released biofortified yellow-flesh cassava was compared to that of a white-flesh cassava, using salt, sugar, and salt-sugar solutions at different temperatures (30, 45, 60 °C) and fixed cube/solution-ratio. Water loss (WL) and solids gain (SG) data were fitted by non-linear regression using four models (Page, Weibull, Azuara, and Peleg). Azuara model was most appropriate in describing OD kinetics for both cultivars. Azuara estimates for equilibrium WL and equilibrium SG, respectively, ranged between 0.101-0.120 and 0.049-0.094 g/g for salt solution, 0.158-0.212 g/g and 0.107-0.268 g/g for sugar solution and 0.234-0.306 g/g and 0.189-0.276 g/g for salt-sugar solution. The best conditions for OD of both cultivars by salt solution and sugar solution was at 60 °C and 45 °C, respectively, while that for salt-sugar solution varied with cultivar. Increasing temperature increased water loss and solids gain. Salt-OD conformed to Arrhenius temperature dependence of diffusivity, but sugar-OD and salt-sugar-OD did not. Micrographs reveal biofortified yellow-flesh cassava was more susceptible to cell wall collapse than white-flesh cassava. Extent of dehydration by OD agents ranked: salt-sugar > sugar > salt. Osmotic dehydration may be useful as a means of dehydration for cassava prior to drying, and is especially relevant for the carotenoids-rich biofortified yellow cassava.

17.
J Food Sci ; 84(7): 1986-1991, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31192461

RESUMO

Cassava leaves are a valuable source of protein but the cyanogenic potential limits their use as food and feed. Four different treatments were investigated to detoxify cassava leaves. Thermal (55 °C for 6 hr), sodium bicarbonate (0.4% NaHCO3 , 55 °C for 6 hr), enzymatic (0.32% Multifect® GC Extra, 4 hr), and ultrasonic treatments (500 W, 35 kHz, 55 °C, 0.25 hr) reduced the total cyanide (µg HCN equivalents per g fresh leaf or ppm) content by 90%, 93%, 82%, and 84% while the cyanide content reduction in the respective controls was 85%, 90%, 79%, and 84%, respectively. The sodium bicarbonate treatment was found to be the most effective treatment. Therefore, it was further optimized by varying time and temperature. A significant effect on the cyanide content was observed by changing the incubation time while no significant effect of temperature was noticed. Nevertheless, extended incubation time during sodium bicarbonate treatment reduced ascorbic acid content by 7% and 39% when leaves were incubated with sodium bicarbonate for 0.5 hr and 48 hr, respectively. PRACTICAL APPLICATION: Cyanogenic glucosides are the major toxic compound in cassava leaves, which limits their use as food and feed. The methods proposed in this study can be used to detoxify cassava leaves, which are generally considered as an inferior by-product. Hence, detoxified cassava leaves may contribute to fulfil world protein demand in an eco-sustainable way.


Assuntos
Cianetos/química , Manipulação de Alimentos/métodos , Glicosídeos/química , Manihot/química , Folhas de Planta/química , Biocatálise , Cianetos/toxicidade , Enzimas/química , Glicosídeos/toxicidade , Temperatura Alta , Manihot/toxicidade , Folhas de Planta/toxicidade , Bicarbonato de Sódio/química , Ultrassom
18.
Bioresour Technol ; 265: 224-235, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29902655

RESUMO

Response surface methodology was used to optimise pyrolysis conditions to produce biochar from maize residues (cobs, husks, leaves and stalks). The aim was to obtain biochar with good potential as an additive for composting. Mathematical models were developed to explain the experimental responses of volatile matter content (VM), ash content (AC), pH and electrical conductivity (EC) to the operating parameters such as temperature, heating rate and holding time. The temperature had the most significant influence on biochar properties. AC, pH and EC significantly increased (p < 0.05) with increasing temperature, while the VM decreased. The holding time showed less effect on the responses, while the heating rate had insubstantial effect. Under the optimal conditions, the husk and leaf biochar had higher AC (11.42 and 26.55%), pH (10.96 and 11.51), and EC (12.37 and 6.79 mS/cm), but lower VM (7.38 and 8.39%) than those of cob and stalk biochar.


Assuntos
Carvão Vegetal , Zea mays , Folhas de Planta , Temperatura
19.
Eng Life Sci ; 18(8): 551-561, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32624935

RESUMO

In this study, the anaerobic performance and stability of coffee husk and pulp with and without trace element (TE) supplement was investigated, using 20 L mesophilic continuous stirred tank reactors for 140 days of experiment (DOE). The TE was cocktail of trace metals composed of Fe, Ni, Zn, Co, Mn, Mo, Se W and B. The organic loading rate (OLR) was increased stepwise from 2.5 (HRT = 40 d) to 6.0 kg VS m-3 d- 1(HRT = 16.7 d). The highest methane productivity from pulp with and without TE was 1.272 and 0.965 m3 m-3 d-1 at an OLR of 6.0 and 5.0 kg VS m-3 d-1; while the husks performed 0.895 and 0.795 m3 m-3 d-1 respectively, both at an OLR of 6.0 kg VS m-3 d-1. The specific methane yield (SMY) of pulp (at OLR = 5 kg VS m-3 d-1) with and without TEs was 217.9 ± 4.7 and 193.1 ± 8.2 L kg-1 VS; while husk yielded 149.2 ± 6.0 and 132.5 ± 4.9 L kg-1 VS, respectively. The effect of TEs on SMY was statistically significant (p < 001) at higher OLRs (5.0 - 6.0 kg VS m-3 d-1). The TEs improved the anaerobic stability through an optimum alkalinity ratio (VFA/TIC < 0.3) and suppressed the accumulation of volatile fatty acids. Mono digestion of husks and pulp are prone to lack Mo, Zn, Ni and Fe in long-term anaerobic fermentation. Further studies on co-digestion of husk/pulp with animal manure and dry fermentation helps to efficiently use this biomass resource.

20.
Bioresour Technol ; 218: 541-51, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27395002

RESUMO

In this study, biochar was produced from maize residues (cobs, husks, leaves) in a lab-scale pyrolysis reactor without using a purging gas. The physicochemical properties of biomass and biochar were analysed. Box-Behnken design was used to optimise operational conditions for biochar yields. Multivariate correlations of biochar yields were established using reduced quadratic models with R(2)=0.9949, 0.9801 and 0.9876 for cobs, husks and leaves, respectively. Biochar yields were negatively correlated with the temperature, which was significantly influenced by the exothermic reactions during the pyrolysis of maize residues. The heating rate was found to have the least effect on biochar yields. Under optimal conditions, the maximum biochar yields from cobs, husks and leaves were 33.42, 30.69 and 37.91%, respectively. The highest biochar yield from maize leaves was obtained at a temperature of 300°C, a heating rate of 15°C/min and a holding time of 30min.


Assuntos
Biomassa , Carvão Vegetal/metabolismo , Temperatura Alta , Folhas de Planta/metabolismo , Zea mays/metabolismo , Reatores Biológicos , Gases/metabolismo , Hidrólise , Casca de Planta/metabolismo , Temperatura
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