Oxalic Acid Pretreatment on Enhancement of Enzymatic Saccharification from Napier Grass for Biofuel Production

Thailand as an agricultural country faces significant challenges in managing the abundant biomass waste generated from agricultural activities. Conventional disposal methods such as incineration contribute to pollution and limited availability of landfill space. To mitigate these issues valorization of this biomass waste has been a solution. This study focuses on the utilization of Napier grass as a renewable energy source. In this experiment, the Napier grass samples were pretreated using oxalic acid with temperature variations (50 – 100 °C), time (30 180 min), and oxalic acid concentration (2 10%w/v) to determine the limit of these three factors for optimization studies. The utilization of Box-Behnken Design (BBD) within Response Surface Methodology (RSM) enabled the determination of optimal pretreatment conditions and the exploration of the correlation between pretreatment factors and reducing sugar content. The model predicted pretreatment with an oxalic acid concentration of 6% w/v, pretreated at 100 °C for 105 min as the optimal pretreatment condition to produce a maximum reducing sugar concentration of 10.65 mg/ml. Therefore, the sample was pretreated at optimum conditions and the results revealed the amount of reducing sugar obtained was 10.67 mg/ml, which differed from the predicted value with an error of 0.22%. Thus, this study provides insight for future researchers on the optimum condition that can be applied for pretreating biomass with oxalic acid to maximize the sugar yield

Effect of Oscillating Magnetic Field on Freezing Rate, Phase Transition Time and Supercooling of Deionized Water

Due to a growing interest toward quality improvement of frozen foods, many advanced technologies have been combined with conventional freezing system to expedite rate of freezing and reduce ice crystal formation. This research aimed to investigate the effect of oscillating magnetic field (OMF) in the range of 0 to 12 mT (50 Hz) on freezing rate, phase transition time and supercooling of deionized water during freezing in an air blast freezer at –10°C. The sample was placed between two magnetic cores where an oscillating magnetic field (OMF) was generated and the temperature profile was recorded by a data logger at 1-minute interval. The magnetic field strength was varied at 0, 4, 8, and 12 mT. It was found that there was no significant difference in the freezing rate and phase transition time when different OMF strengths were applied (p > 0.05). Interestingly, the probability of supercooling occurrence increased when the OMF was applied; without OMF only 16% of the experiment exhibited supercooling phenomenon where 33% was detected when OMF in the range of 4–12 mT was applied. However, the probability of supercooling occurrence was independent of the OMF strength

Effect of Moisture Adjustment on Physico-chemical Properties, Durability and Production Efficiency of Broiler Feed Pellets

This study aims to investigate effect of moisture adjustment on physico-chemical properties, durability and production efficiency of broiler feed pellets. Three levels of moisture content (12, 13 and 14% wet basis) were adjusted by adding water at mixing step prior to pelletizing. The properties of pellets including moisture content, gelatinization behavior, pellet durability, density and length were determined. Moisture adjustment significantly increased moisture content of the final pellets (p < 0.05) but did not affect gelatinization behavior, pellet durability and density. The pellet length slightly decreased as the initial moisture content increased. Production efficiency was improved when increasing moisture content up to 14% while the quality of pellet remains the same. Thus, appropriate level of moisture adjustment at the mixing step could improve production efficiency of feed pellets

Effect of Extraction Methods on Antibacterial Activity and Chemical Composition of Chinese Chives (Allium tuberosum Rottl. ex Spreng) Extract

The Bang-Phae organic vegetable grower community enterprise group, Ratchaburi province is one of the largest Chinese chives (Allium tuberosum Rottl. ex Spreng) growers in Thailand. However, not all of its Chinese chives meet the standard of retail markets and were sorted out. Producing Chinese chives extract is an alternative way to add value to the rejected produces. The Chinese chives essential oil contains many new and known bioactive compounds. Therefore, this experiment was aimed to study the antibacterial activity of Chinese chives extracts using 17 difference extraction conditions (Steam distillation for 1.0, 2.0, 2.5, 3.0 h; Ohmic pretreatment followed by steam distillation for 1.0, 2.0, 2.5, 3.0 h; 95% ethanol, hexane, soy bean oil extraction using dried, fresh and frozen Chinese chives) against 6 different pathogenic bacterium (Escherichia coli ATCC25822, Salmonella enterica Typhimurium U302, S. enterica Enteritidis, S. enterica 4,5,12:i (human) US clone, Bacillus cereus and Listeria monocytogenes 10403S). The disc agar diffusion method with 3 different concentrations of extracts (25, 50, 75 mg/mL) was used to evaluate the antibacterial activity. The results showed that different extraction conditions significantly affected the antibacterial activity. The higher extract concentration resulted in the better antibacterial activity. This finding indicated that both extraction condition and extract concentration significantly influence antibacterial activity. The extracts obtained from thermal extraction seem to have higher antibacterial activity than the ones obtained from cold extraction. The extract obtained from steam distillation for 2.5 h resulted in the highest antibacterial activity; 75 mg/mL of the extract caused 0.688 ±0.023 cm clear zone against B. cereus and L. monocytogenes 10403S. The chemical composition profile using GC-MS showed high percentage of organosulfide volatile compounds in thermally extracted Chinese chives. Therefore, the organosulfide volatile compounds might be responsible for effective bacteria inhibition

The Antibacterial and Antioxidant Activity of Centella Asiatica Chloroform Extract-loaded Gelatin Nanoparticles

Nanoencapsulation of Centella asaitica (CA) crude chloroform extract seems to be an attractive approach that may improve drug bioavailability and drug delivery system. In the study, CA extract-loaded gelatin nanoparticles (CGNP) were developed by gelatin one-step and two-step desolvation methods, using three different ratios between CA crude chloroform extract and gelatin (1:2, 1:3, and 1:4 w/w). The antibacterial and antioxidants activities of CGNP and CA were compared. The antioxidant activity of CGNP and CA was evaluated by using DPPH radical scavenging assay and ferric reducing antioxidant power (FRAP) assay. Results showed an enhancement of CGNP antibacterial activity against food borne pathogen. The highest inhibition diameters and FRAP determined from CGNP prepared by one-step at 1:4 ratios (1.03±0.39 cm and 1.23±019 mmol Fe2+/mg dried weight, respectively). However, CGNP was no significant difference in DPPH radical scavenging activity compared to CA. These results provide useful information for developing effective nanoencapsulation of CA as effective natural ingredient

Optimization of Alkyl Imidazolium Chloride Pretreatment on Rice Straw Biomass Conversion

Conversion of lignocellulosic biomass to value-added biochemicals and biofuels have gained importance nowadays as a method to reduce environmental problems and to increase economical profits of wastes. One of the main bottleneck of this process is the ineffective hydrolysis of biomass to small sugars due to recalcitrant structure of lignocellulosic biomass. To improve enzymatic hydrolysis, ionic liquid pretreatment on rice straw was optimized to determine the operational condition. Here, two types of ionic liquids, including 1-Butyl-3-methyl imidazolium chloride (BMIM-Cl) and 1-Ethyl-3-methy limidazolium chloride (EMIM-Cl), were challenged with different pretreatment conditions based on Response Surface Methodology (RSM) and their pretreatment efficiencies were comparatively monitored. The pretreatment models representing the effects of BMIM-Cl and EMIM-Cl pretreatment parameters on sugar yields were generated with high R2 value at 0.9720 and 0.9356, respectively, advocating the reliabilities of the models. Validation experiments were performed to determine the power of model prediction and results showed that there were only 6.3 and 4.86% error in the cases of BMIM-Cl and EMIM-Cl pretreatments, respectively. In this study, BMIM-Cl pretreatment had higher efficiency on improvement of rice straw saccharification compared to EMIM-Cl pretreatment for 35.39%. The results suggested the importance of optimization before selection of pretreatment condition to different types of lignocellulosic biomass

Itaconic Acid: A Promising and Sustainable Platform Chemical?

Due to the increasing demand and focus for sustainable chemicals and fuels that are independent from fossil resources, itaconic acid gained interest and recognized for market position as a potential bio-based platform chemical. Itaconic acid can be produced via a chemical pathway or a biotechnological pathway, the more effective production way is the latter one, which is currently conducted in industrial scale production. In order to replace fossil-based chemicals, the efficiency of the current production that is mainly operated by using Aspergillus terreus has to be improved to achieve the economically feasible process. The recent progress in understanding the biosynthesis pathway, finding new raw materials and microbes as well as applying a more effective downstream process, facilitated the optimization of existing processes and resulted in reduction of production cost. However, there is still need for further optimization to achieve higher final concentrations and to use a broader range of low cost sustainable raw materials. Nowadays, the largest industrial producers of itaconic acid are located in China and the USA. If the production costs can be reduced and the downstream value chain for itaconic acid can be expanded, the market could be grow in the future

Improvement of Anthocyanin Stability in Butterfly Pea Flower Extract by Co-pigmentation with Catechin

Most of the food processing operations involve the use of heat which generally causes alteration, and degradation of natural pigments, resulting in lower stability. One of the stability enhancement methods is co-pigmentation. This study aimed to determine effect of catechin co-pigment on stability of anthocyanins in Clitoria ternatea (or butterfly pea flower) extract. Degradation kinetics of anthocyanins in the extract were evaluated at three temperatures (28, 60, and 90℃). The effect of co-pigment ratio (catechin: anthocyanins at 1:1, 50:1 and 100:1 by weight) on the stability of anthocyanin extract at 90℃ was determined by the pH differential method. It was found that anthocyanin degradation followed the zero- order kinetics at all temperatures; the degradation rate increased as the temperature increased. At a lower pH, anthocyanins became more stable. An increase in the co-pigment ratio significantly retarded the degradation anthocyanins at 90℃. In addition, co-pigmentation also intensified the color of butterfly pea extract. The highest anthocyanin stability was obtained at co-pigment ratio of 100:1

The Antibacterial and Antioxidant Activity of Centella Asiatica Chloroform Extract-loaded Gelatin Nanoparticles

Nanoencapsulation of Centella asaitica (CA) crude chloroform extract seems to be an attractive approach that may improve drug bioavailability and drug delivery system. In the study, CA extract-loaded gelatin nanoparticles (CGNP) were developed by gelatin one-step and two-step desolvation methods, using three different ratios between CA crude chloroform extract and gelatin (1:2, 1:3, and 1:4 w/w). The antibacterial and antioxidants activities of CGNP and CA were compared. The antioxidant activity of CGNP and CA was evaluated by using DPPH radical scavenging assay and ferric reducing antioxidant power (FRAP) assay. Results showed an enhancement of CGNP antibacterial activity against food borne pathogen. The highest inhibition diameters and FRAP determined from CGNP prepared by one-step at 1:4 ratios (1.03±0.39 cm and 1.23±019 mmol Fe2+/mg dried weight, respectively). However, CGNP was no significant difference in DPPH radical scavenging activity compared to CA. These results provide useful information for developing effective nanoencapsulation of CA as effective natural ingredient

Influence of Nitrate-nitrite Contamination on Pink Color Defect in Ginger Marinated Steamed Chicken Drumsticks

This study aimed at investigating influence of nitrate-nitrite contamination in ginger on pink color defect in marinated steamed chicken drumsticks. Three marinade formulations representing different degrees of nitratenitrite contamination were explored (i.e. no ginger (0 ppm) – A, ginger paste #1 containing 30 ppm nitrate – B, and ginger paste #2 containing 30 ppm nitrate + 8 ppm nitrite – C, respectively). Total myoglobin content was measured in chicken drumsticks before marination. Nitric oxide myoglobin (NOMb) was determined in the samples both before and after marination. After cooking, occurrences of pinking, a* value and nitrosyl hemochrome (NHC) content were evaluated. It was found that pink color defect was observed in treatment C. These results indicated that the presence of nitrite in ginger (treatment C) played a significant role in pinking appearance of steamed chicken drumstick. The maximum nitrite contamination in chicken drumstick was also investigated using sodium nitrite solution and it was found that it should not be more than 0.8 ppm. Thus, it is crucial to control the amount of nitrite contamination in ginger paste to avoid pink color defect formation