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Food waste and crude glycerol were anaerobically co-digested for 100 days at 52 +/- 1 degrees C with an organic loading rate of 1.0 g L-1 d(-1). This long-term thermophilic anaerobic digestion (AD) system encountered severe inhibition from volatile fatty acids (VFAs). The study investigated the impacts of re-inoculation (RI) and biochar addition (BA) on this AD process, and monitored the variation of pH, VFAs, total alkalinity and total ammonia nitrogen during treatment. RI treatment was effective in the short term by recovering reactivity after inhibited sludge was mixed 1:1 with active inoculant. In the long term, RI could not reverse process imbalance and finally failed on day 56. Superior performance in methane production and process stability was observed in BA reactors when compared with control and RI reactors. Overall, the biochar contributed to alkalinity and facilitated the activation of methanogenesis and stimulated the conversion of VFAs.

Salt stress in plants presents a major challenge to future agricultural production. Digestate has various effects on plant growth, but little information is available on its effects on the antioxidant system and physiological characteristics of lettuce under salt stress. In this study, the impacts of mineral fertilizer and digestate application on edible parts of lettuce were compared under three salinities. Experimental treatments comprised application of two types of fertilizer (mineral fertilizer and digestate) and three NaCl concentrations (0, 3, and 7.5 dS m(- 1)). High NaCl concentrations resulted in significantly lower photosynthesis, growth, and physiological indices compared with those under no NaCl addition. However, under the 7.5 dS m(- 1) NaCl condition, digestate application (DA) increased the fresh weight (42%), dry weight (27%), photosynthetic pigment contents and photosynthesis (20%) of lettuce compared with that under mineral fertilizer application (MFA). Accumulation of reactive oxygen species was markedly lower, and the membrane stability index was therefore higher, under DA compared with under MFA within the same salinity level. Lipid peroxidation was lower under DA compared with under MFA in all salinity treatments. Salt stress up-regulated the antioxidant system and DA further increased the enzymatic and non-enzymatic antioxidant capability compared with that under MFA. In addition, the total water use was lower and water-related indices, such as water use efficiency of fresh weight, water use efficiency of dry weight and relative water content, were higher under DA compared with under MFA. The application of digestate instead of mineral fertilizer could be a promising practice to alleviate the negative impact of salt stress on the productivity and physiological characteristics of lettuce plants.

Salt stress in plants presents a major challenge to future agricultural production. Digestate has various effects on plant growth, but little information is available on its effects on the antioxidant system and physiological characteristics of lettuce under salt stress. In this study, the impacts of mineral fertilizer and digestate application on edible parts of lettuce were compared under three salinities. Experimental treatments comprised application of two types of fertilizer (mineral fertilizer and digestate) and three NaCl concentrations (0, 3, and 7.5 dS m(- 1)). High NaCl concentrations resulted in significantly lower photosynthesis, growth, and physiological indices compared with those under no NaCl addition. However, under the 7.5 dS m(- 1) NaCl condition, digestate application (DA) increased the fresh weight (42%), dry weight (27%), photosynthetic pigment contents and photosynthesis (20%) of lettuce compared with that under mineral fertilizer application (MFA). Accumulation of reactive oxygen species was markedly lower, and the membrane stability index was therefore higher, under DA compared with under MFA within the same salinity level. Lipid peroxidation was lower under DA compared with under MFA in all salinity treatments. Salt stress up-regulated the antioxidant system and DA further increased the enzymatic and non-enzymatic antioxidant capability compared with that under MFA. In addition, the total water use was lower and water-related indices, such as water use efficiency of fresh weight, water use efficiency of dry weight and relative water content, were higher under DA compared with under MFA. The application of digestate instead of mineral fertilizer could be a promising practice to alleviate the negative impact of salt stress on the productivity and physiological characteristics of lettuce plants.

Food waste and crude glycerol were anaerobically co-digested for 100 days at 52 +/- 1 degrees C with an organic loading rate of 1.0 g L-1 d(-1). This long-term thermophilic anaerobic digestion (AD) system encountered severe inhibition from volatile fatty acids (VFAs). The study investigated the impacts of re-inoculation (RI) and biochar addition (BA) on this AD process, and monitored the variation of pH, VFAs, total alkalinity and total ammonia nitrogen during treatment. RI treatment was effective in the short term by recovering reactivity after inhibited sludge was mixed 1:1 with active inoculant. In the long term, RI could not reverse process imbalance and finally failed on day 56. Superior performance in methane production and process stability was observed in BA reactors when compared with control and RI reactors. Overall, the biochar contributed to alkalinity and facilitated the activation of methanogenesis and stimulated the conversion of VFAs.

Despite the importance of the biodegradability of lignocellulose biomass, few studies have evaluated the lignocellulose biomass digestion kinetics and modeling of the process. Anaerobic digestion (AD) is a mature energy production technique in which lignocellulose biomass is converted into biogas. However, using different organic waste fractions in AD plants is challenging. In this study, lignocellulose biomass (corn stover hydrochar) obtained from hydrothermal carbonization at a temperature, residential time, and biomass/water ratio of 215 degrees C, 45 min, and 0.115, respectively, was added to the bioreactor as a substrate inoculated with food waste and cow dung to generate biogas. A state-space AD model containing one algebraic equation and two differential equations was constructed. All the parameters used in the model were dependent on the AD process conditions. An adaptive identifier system was developed to automatically estimate parameter values from input and output data. This made it possible to operate the system under different conditions. Daily cumulative biogas production was predicted using the model, and goodness-of-fit analysis indicated that the predicted biogas production values had accuracies of >90% during both model construction and validation. Future work will focus on the application of modeling predictive control into an AD system that would comprise both models and parameters estimation.

To realize the utilization of the valorization of buckwheat waste (BW), a two-stage thermal-chemical process was explored and evaluated to produce saccharides and biochar. During the first stage, BW underwent a hydrothermal extraction (HTE) of varying severity to explore the feasibility of saccharides production; then, the sum of saccharides yields in the liquid sample were compared. A higher sum of saccharides yields of 4.10% was obtained at a relatively lower severity factor (SF) of 3.24 with a byproducts yield of 1.92 %. During the second stage, the contents of cellulose, hemicellulose, and lignin were analyzed in the residue after HTE. Enzymatic hydrolysis from the residue of HTE was inhibited. Thus, enzymatic hydrolysis for saccharides is not suitable for utilizing the residue after HTE of BW. These residues with an SF of 3.24 were treated by pyrolysis to produce biochar, providing a higher biochar yield of 34.45 % and a higher adsorption ability (based on methyl orange) of 31.11 % compared with pyrolysis of the raw BW. Meanwhile, the surface morphology and biomass conversion were analyzed in this study. These results demonstrate that the two-stage thermal-chemical process is efficient for treating BW and producing saccharides and biochar. This work lays a foundation for the industrial application of BW, and for improving the economic benefits of buckwheat cultivation.

To realize the utilization of the valorization of buckwheat waste (BW), a two-stage thermal-chemical process was explored and evaluated to produce saccharides and biochar. During the first stage, BW underwent a hydrothermal extraction (HTE) of varying severity to explore the feasibility of saccharides production; then, the sum of saccharides yields in the liquid sample were compared. A higher sum of saccharides yields of 4.10% was obtained at a relatively lower severity factor (SF) of 3.24 with a byproducts yield of 1.92 %. During the second stage, the contents of cellulose, hemicellulose, and lignin were analyzed in the residue after HTE. Enzymatic hydrolysis from the residue of HTE was inhibited. Thus, enzymatic hydrolysis for saccharides is not suitable for utilizing the residue after HTE of BW. These residues with an SF of 3.24 were treated by pyrolysis to produce biochar, providing a higher biochar yield of 34.45 % and a higher adsorption ability (based on methyl orange) of 31.11 % compared with pyrolysis of the raw BW. Meanwhile, the surface morphology and biomass conversion were analyzed in this study. These results demonstrate that the two-stage thermal-chemical process is efficient for treating BW and producing saccharides and biochar. This work lays a foundation for the industrial application of BW, and for improving the economic benefits of buckwheat cultivation.

The process instability of anaerobic digestion (AD) is a common issue and may result in underperformance or short-term process failure. Extensive research has shown that total solids (TS) content in AD has a significant impact on system stability and performance. However, no study has examined the feasibility of stabilizing the AD process by maintaining constant TS content in the digestate. In this study, an innovative control approach based on constant TS content in the digestate during AD was developed using a mass balance equation. Two levels of TS content (desired values of 4% wet basis (w.b.) and 6% w.b.) were compared with conventional control. The process stability was examined by monitoring digestate components and pH. Substrate-specific methane yield (m(3) CH4/kg VS) was used to assess the effectiveness of the controlled conditions. The results showed that the digestate TS content during AD can be controlled and that the digestion process can be stabilized by controlled conditions. In addition, constant TS in the digestate (within 1% w.b. of the desired level) gave increased levels of biogas production (10.2%), methane (13.5%), and substrate-specific methane yield (43.3%) at 4% TS, and respective increases of 16.6%, 21.2%, and 20.8% at 6% TS when compared with standard operation.

Antioxidant polyphenols in black tea residue are an underused source of bioactive compounds. Microencapsulation can turn them into a valuable functional ingredient for different food applications. This study investigated the potential of using spent black tea extract (SBT) as an active ingredient in food packaging. Free or microencapsulated forms of SBT, using a pectin-sodium caseinate mixture as a wall material, were incorporated in a cassava starch matrix and films developed by casting. The effect of incorporating SBT at different polyphenol contents (0.17% and 0.34%) on the structural, physical, and antioxidant properties of the films, the migration of active compounds into different food simulants and their performance at preventing lipid oxidation were evaluated. The results showed that adding free SBT modified the film structure by forming hydrogen bonds with starch, creating a less elastic film with antioxidant activity (173 and 587 mu g(GAE)/g film). Incorporating microencapsulated SBT improved the mechanical properties of active films and preserved their antioxidant activity (276 and 627 mu g(GAE)/g film). Encapsulates significantly enhanced the release of antioxidant polyphenols into both aqueous and fatty food simulants. Both types of active film exhibited better barrier properties against UV light and water vapour than the control starch film and delayed lipid oxidation up to 35 d. This study revealed that starch film incorporating microencapsulated SBT can be used as a functional food packaging to protect fatty foods from oxidation.

Hydrothermal gasification (HTG) experiments were carried out to extract hydrogen from biomass. Although extensive research has been conducted on hydrogen production with HTG, limited research exists on the use of biochar as a raw material. In this study, woodland residues (wood chip) and biochar from wood-chip pyrolysis were used in HTG treatment to generate hydrogen. This research investigated the effect of temperature (300-425 degrees C) and biomass/water (0.5-10) ratio on gas composition. A higher temperature promoted hydrogen production because the water-gas shift reaction and steam-reforming reaction were promoted with an increase in temperature. The methane concentration was related positively to temperature because of the methanation and hydrogenation reactions. A lower biomass/water ratio promoted hydrogen production but suppressed carbon-monoxide production. Most reactions that produce hydrogen consume water, but water also affects the water-gas shift reaction balance, which decreases the carbon-monoxide concentration. By focusing on the practical application of HTG, we attempted biochar treatment by pyrolysis (temperature of heating part: 700 degrees C), and syngas was obtained from hydrothermal treatment above 425 degrees C.

To enhance anaerobic fermentation during food waste (FW) digestion, pretreatments can be applied or the FW can be co-digested with other waste. In this study, lipase addition (LA), hydrothermal pretreatment (HTP), and a combination of both methods (HL) were applied to hydrolyze organic matter in FW. Furthermore, the effects of crude glycerol (CG), which provided 5%, 10%, and 15% of the volatile solids (VS) as co-substrate (denoted as CG5, CG10, and CG15, respectively), on the anaerobic digestion of FW were assessed. With an increasing proportion of CG in the co-digestion experiment, CG10 showed higher methane production, while CG15 negatively affected the anaerobic digestion (AD) performance owing to propionic acid accumulation acidifying the reactors and inhibiting methanogen growth. As the pretreatments partially decomposed hard-to-degrade substances in advance, pretreated FW showed a stronger methane production ability compared with raw FW, especially using the HL method, which was significantly better than co-digestion. HL pretreatment was shown to be a promising option for enhancing the methane potential value (1.773 NL CH4/g VS) according to the modified Gompertz model.

Spent black tea (SBT) is a residue from tea beverage production and considered as a potential source of active polyphenols. This study aimed to develop a pilot-scale process on semi-continuous subcritical solvent extraction (SSE) of polyphenols from SBT by exploiting the lab-scale knowledge. Treatment of SBT with ethanol-water (50% w/w) as solvent at 125 degrees C and 0.3 MPa achieved a significantly higher yield of polyphenols (80.82 g gallic acid equivalents/kg black tea) with antioxidant activity (64.20 g gallic acid equivalents/kg black tea), compared to hot water extraction (HWE). SSE increased the soluble matter content in extracts than HWE. Based on the results of LC-MS, theaflavin-3,3 '-digallate was the most abundant polyphenol from a total of 12 compounds to be extracted by SBT with 50% ethanol. The results suggested that SSE can be used as a scale-up extraction method to recover polyphenols from SBT.

The hydrolysis of levan using compressed hot water for the production of functional fructooligosaccharides (FOSs) was investigated. Levans from Erwinia herbicola (EH) and Halomonas smyrnensis (HS) were characterized using scanning electron microscopy and light scattering techniques, and hydrolyzed using compressed hot water at four temperatures (120, 140, 160, and 180 degrees C). The hydrolysates were analyzed using high-performance liquid chromatography and electrospray ionization-mass spectrometry. Levan HS showed a crystalline morphology, whereas levan EH showed an aggregated structure. Both levans had molar masses on the order of 10(6) g/mol, but levan EH had a smaller radius of gyration, hydrodynamic radius, and intrinsic viscosity. Levan EH hydrolyzed into FOSs at approximately 120 degrees C, whereas levan HS required a temperature of at least 160 degrees C, possibly because of differences in the degree of branching of the two levans. Both samples were degraded to fructose when treated at 180 degrees C.

Corn stover is an abundant and underused source of lignocellulose waste biomass that can be transformed into a high-quality energy resource using hydrothermal carbonization (HTC). This investigation has focused on the effect of processing parameters on the products of HTC-namely solid fuel or hydrochar and liquid and gas fractions. HTC was conducted in a temperature-controlled small batch reactor with corn stover and deionized water under oxygen-free conditions obtained by pressurizing the reactor headspace with nitrogen gas. The properties of the hydrochar and liquid and gas fractions were evaluated as a function of the process temperature (250-350 degrees C), residence time (30-60 min) and biomass/water ratio (0.09-0.14). Central composite design modules in a response surface methodology were used to optimize processing parameters. The maximum mass yield, energy yield and high heating value (HHV) of the hydrochar produced were 29.91% dry weight (dw), 42.38% dw and 26.03 MJ/kg, respectively. Concentrations of acetic acid and hydrogen gas were 6.93 g/L and 0.25v/v%, respectively. Experimental results after process optimization were in satisfactory agreement with the predicted HHV. The optimal HTC process parameters were determined to be 305 degrees C with a 60 min residence time and a biomass/water ratio of 0.114, yielding hydrochar with a HHV of 25.42 MJ/kg. The results confirm the feasibility of an alternative corn stover management system.

The aim of this study was to determine the appropriate strategy for cattle manure composting with forced aeration. The composting of cattle manure was conducted using an 18.8 L reactor with three different amounts of total air supplied (1080, 3240 and 10,800 L/kg dry mass) during 360 h of composting using continuous and on/off sequencing (20 min/h) aeration methods and three turning patterns (no turning, full turning and turning with position change). The degradation of organic matter in three-stage systems (the compost was turned every 120 h over the 360 h period) was significantly affected by total air supply volume and was large in the case of on/off sequence aeration. The pattern of moisture change was more affected by turning than by aeration modes. The optimal composting conditions for organic matter degradation (maximum of 37.7%) were aeration rate: 0.45 L/min kg dm, aeration mode: on/off sequencing process and full turning. The total accumulated weight losses and heat generated during composting indicated significant effects of the total air supplied and were large in the case of the continuous process.

Fissuring associated with kernel elongation was evident in a moisture-adsorbing environment at 15 °C of relative humidity 88.72±0.28% with moisture content from 6% (d.b.) to 16.3% (d.b.). The average length and width of 800 kernels was measured during the sorption test using a Cervitec Grain Inspector equipped with two digital cameras. Samples were exposed to both a moisture-adsorbing and desorbing environments at 15 °C with relative humidities of 23.4±0.53%, 55.9±0.27%, 70.98±0.28% and 88.72±0.28%. On image analysis, the kernels changed in size from 5.13 to 4.84 mm in length and 2.9 to 2.73 mm in width. Both length and width changed as expected during moisture-adsorbing and moisture-desorbing tests. Fissured kernel percent was related to changes in the average length of the kernels during the moisture-adsorbing tests. The average length and fissured kernel percent of rice kernels measured by image analysis may be considered as a reliable indicator of changes in their dimensions during quasi-static moisture sorption processes.

Fissure formation Mechanism of Kaori aromatic rice under different drying and post-drying conditions was investigated by differential scanning calorimetry (DSC). Samples dried at 50℃ and 60℃ to standard and low final moisture content (FMC), the maximum fissuring rate occurred after approximately 12 h. Increasing difference between storage and drying air temperatures increased fissured kernels. The mean value of glass transition temperatures (Tg) showed that to achieve a FMC up to 12% and 9%, the temperature must be below 45℃ and 52℃, respectively. Drying temperatures higher than these are likely to produce a high proportion of fissured kernels. The DSC diagram indicated that at the onset of drying, kernels state changed from a glassy to a rubbery and during the drying it returned to the glassy state. Therefore fissured kernels at low FMC was approximately 10% more than standard FMC. It can be concluded that a high drying temperature might have a more negative effect than low FMC on the structure of Kaori aromatic rice and leads to deterioration in its quality.

Hygroscopy of hybrid rice affects storage, handling, and processing. The thermodynamic relationship upon which the estimate of isosteric heat is based is the Clausius-Clayperon equation. The net isosteric heat of sorption was determined from the slope of the ln(rh) versus 1/T lines at a constant moisture content. Net isosteric heat of desorption was found higher than that for the adsorption within a moisture content range of 12–20% for all of the rice kernels. The net isosteric heats of desorption and adsorption were higher for hybrid rough rice kernels followed by brown rice and milled rice kernels, respectively. An empirical equation was fitted to describe the net isosteric heats of hybrid rice kernels as a function of moisture content and was found adequate to predict the net isosteric heats. The intercept K was also found to be a function of moisture content and the model predicted the K value well (r2 = 0.85 for adsorption and r2 = 0.92 for desorption). This set of two equations would be useful in the simulation of hybrid rice during storage.