Initial Acid Value Research Articles

Storage and time course effects on the quality of oil extracted from Phyllanthus amarus Schumach and Annona muricata Linn and their antidiabetic potentials.

With the advent of modern technology, advancements in processing and storage techniques, and increasing medical knowledge, people are becoming aware of deterioration in the quality of medicinal products due to storage methods and time. In most cases, herbal products are not consumed immediately after production; as such, improper storage can result in physical, chemical, and microbiological changes. The study evaluated the effect of storage methods and time on the quality of oil extracted from Phyllanthus amarus Schumach and Annona muricata Linn and assessed their antidiabetic and antioxidative effects. Plants were air-dried, pulverized, and then subjected to Soxhlet extraction in petroleum ether. The oil was evaluated for phytochemical constituents and the effects of time and storage methods on its physicochemical properties. Characterization of the oil was done by spectroscopic techniques. Oils from both plants contained tannins, flavonoids, alkaloids, steroids, glycosides, terpenoids, phlobotannins, resins, reducing sugar, phenols, and saponins in different proportions. The oil from A. muricata had higher phenolic (3.11 ± 0.31 mg GAE/g), flavonoid (11.82 ± 0.08 mg QUE/g), alkaloid (16.37 ± 0.56 mg APE/g), and tannin (7.13 ± 0.47 mg CE/g) contents than the oil from P. amarus, which had 0.54 ± 0.08 mg GAE/g, 7.83 ± 0.13 mg QUE/g, 9.87 ± 0.15 mg APE, and 3.16 ± 0.12 mg CE/g for total phenolic, flavonoids, alkaloids, and tannins, respectively. Initial acid, iodine, peroxide, and saponification values recorded for P. amarus were 5.63 ± 0.82 mg KOH/g, 97.17 ±0.53 Wijis, 9.31 ± 0.15 mEq/kg, and 116.11 ± 0.74 mg KOH/g, respectively, significantly different from those of A. muricata , which had values of 1.17 ± 0.08 mg KOH, 76.23 ± 0.03 Wijis, 6.75 ± 0.47 mEq/kg, and 193.31 ± 0.52 mg KOH/g, respectively. FT-IR characterization of the oils revealed the presence of carboxylic acid, alkyl, alkene, alkane, haloalkane, aldehyde, aromatic amine, α-unsaturated and β-unsaturated esters, and phenol functional groups. P. amarus oil inhibited α-amylase (IC50 0.17 ± 0.03 mg/ml), α-glucosidase (IC50 0.64 ± 0.03 mg/ml), and xanthine oxidase (0.70 ± 0.01 mg/ml) to a greater extent than A. muricata oil, with IC50 values of 0.43 ± 0.05 mg/ml (α-amylase), 2.25 ± 0.31 mg/ml (α-glucosidase), and 0.78 ± 0.07 mg/ml (xanthine oxidase). This study showed that oils from the tested plants have low rancidity with a moderate shelf life. The extracts contained essential phytoconstituents that significantly inhibited α-glucosidase and xanthine oxidase. These effects of the oil indicate their potential to prevent diabetes, gout, and oxidative stress. Consequently, the supply of P. amarus and A. muricata in homemade diets is strongly encouraged for healthy living.

Experimental investigation on storage of food grains using cow dung-based desiccant as preservative

ABSTRACT Food grains, produced abundantly during the harvest season, face the challenge of maintaining their quality for extended periods. While immediate consumption is an option, long-term storage offers distinct advantages by ensuring a continuous food supply beyond the harvest season. Proper storage is a critical post-harvest factor that contributes to various benefits, including economic growth and food security. In this context, this paper presents an experimental study focused on the development and evaluation of a hybrid cow dung-based desiccant (HCDD) as a potential preservative for food grains. The study thoroughly examines the impact of this innovative desiccant, HCDD, on the quality of stored rice and wheat grains. Initially, the lipid content of rice grains in C3 and C4 drums was recorded at 1.97%. However, after 8.5 months of storage, a significant decline in quality was observed in C3, where the lipid content decreased to 1.78%. In contrast, C4 maintained a stable lipid content at 1.89%. Similarly, the initial free fatty acid content in rice grains in both C3 and C4 drums was 1.78%, but after 8.5 months, C3 experienced a significant increase to 7.48%, indicating substantial deterioration. Conversely, C4 exhibited a more modest increase, reaching 4.29% over the same period. Regarding wheat quality, the initial gluten content in C1 and C2 drums was 28.12%. After 5.5 months of storage, C1 exhibited a considerable decline, with gluten content decreasing to 17.62%. In contrast, C2, utilizing HCDD, displayed a milder decrease, reaching 19.1% after 13 months. Furthermore, the initial acid value in C1 and C2 drums for wheat grains was 10.2 mg KOH/g fat. After 5.5 months, C1 experienced a substantial increase in the acid value, rising to 26.8 mg KOH/g fat, indicating grain deterioration. Conversely, C2, benefiting from HCDD, exhibited a less pronounced increase, with an acid value of 15.4 mg KOH/g fat after 13 months. This study meticulously monitored the quality of stored grains by measuring crucial parameters such as lipid content, free fatty acids in rice, gluten, and acid values in wheat. The consistent findings revealed that grains stored with HCDD exhibited superior preservation qualities. They retained lower levels of moisture and experienced significantly slower deterioration rates compared to those stored without HCDD. This not only enhances the shelf life of grains but also ensures their nutritional and qualitative integrity.

Production of Rosmarinic Acid Nanoparticles, and Investigation of Anti-Oxidation Effects on Salmon Fish Meat

In this study, an anti-oxidant nanoformulation to prevent the oxidation of salmon was developed using rosmarinic acid (RA). Minced salmon samples (MSs) were treated with 8.10-3 g (RAT1) and 16.10-3 g (RAT2) RA-loaded nanoparticles for 100 g MS rosmarinic acid, separately. The thiobarbituric acid (TBA) values of control (C), RAT1, and RAT2 samples stored at 4 °C were found as 2.995, 1.350, and 0.994 mg MDA/kg; respectively, after 9 days. While the initial free fatty acid (FFA) value of C samples was 2.011%, RAT1 and RAT2 were found as 2.765% and 2.494%, respectively. The 2,2,diphenylpicrylhydrazyl (DPPH) values of MSs treated with RAT1 and RAT2 were observed to be higher than that of C samples. C samples were evaluated as unfit for human consumption on the 5th day of the storage, it was revealed that but the sensory scores of MSs treated with RAT1 and RAT2 were still acceptable for human consumption.

Process Optimization for Biodiesel Production from Highly Acidic Hibiscus Cannabinus (Deccan Hemp) Oil

In this study, Hibiscus Cannabinus (deccan hemp) oil was used to convert its methyl ester. Methyl ester synthesis process involves of two-steps: esterification of sulfuric acid (Step-1) and alkaline transesterification (Step-2). Deccan hemp oil was found to have an initial acid value of 12.48 mg KOH/g. The acid value of deccan hemp oil was decreased to below 2 mg KOH/g in Step-1 taking consideration to get higher ester yield after alkaline transesterification process. The alkaline transesterification process parameters such as methyl alcohol to deccan hemp oil molar ratio, sulfuric acid catalyst amount, reaction temperature and reaction time were optimised and analysed in detail. This process gives ester yield of about 95.48%. The important properties of the synthesised methyl ester were determined and compared with IS 51607 and ASTM D6751 biodiesel standards.

Cocoa pod husk-plantain peel blend as a novel green heterogeneous catalyst for renewable and sustainable honne oil biodiesel synthesis: A case of biowastes-to-wealth

The present study investigated honne oil methyl esters (HOME) production from crude honne seed oil (HSO) using a novel catalyst synthesized from a blend of cocoa pod husk and plantain peel. A two-step esterification-transesterification method was used for the HOME production. For the esterification, the crude HSO was pretreated with H2SO4 to reduce its very high acid value to an acceptable level prior to transesterification to biodiesel. Characterization of the calcined cocoa pod husk-plantain peel ash (CCPA) showed that K (50.95%), Mg (2.49%) and Ca (2.30%) were the major metals present, thereby confirming its heterogeneity. Physisorption isotherms obtained for the CCPA indicate it is composed of nanoparticles that are mesoporous in nature. The initial high acid value of the oil (35.5 g KOH/g oil) was reduced to 1.68 ± 0.57 g KOH/g oil via esterification at a temperature of 65 °C, MeOH:HSO molar ratio of 50:1 and H2SO4 of 2 vol% after 2.5 h. The best operating condition that gave maximum HOME yield (98.98 ± 0.04 wt%) was CCPA amount of 4.5 wt%, reaction temperature of 65 °C, time of 2.5 h and MeOH:pretreated HSO molar ratio of 15:1. The HOME produced satisfied standard limits set for biodiesel.

Thermo-degradative changes of rapeseed and sunflower oils during deep-frying French fries

The purpose of this study was to investigate changes in TPCs, acid value and peroxide value as well as fatty acids composition in edible oils during french fries production. Lower TPCs content was found in rapeseed oil (3.3%) and the threshold (24%) was achieved on the fourth day. The total time for the deterioration of deep-frying rapeseed oil was 23½ hours. On the contrary, in fresh sunflower oil at the first day was TPCs content 5.5% and the limit of 24% was reached on the third day. The total time for the deterioration of deep-frying sunflower oil was 17½ hours. The results indicated significant differences (<0.05) in TPCs content between rapeseed and sunflower oils during deep-frying process. At the beginning of deep-frying French fries in rapeseed oil, the acid number was 0.374 mg KOH.g-1 and 1.271 mg KOH.g-1 at the fourth day of deep-frying. The measured peroxide value was 4.3 mEq O2.kg-1 at the beginning and at the end of deep-frying 10.5 mEq O2.kg-1. The initial peroxide and acid values were higher in sunflower oil compared with rapeseed oil, respectively. It should be note, then the acid values and peroxide values, respectively, in the two fresh oils used in this study were below the limit of refined oil according to Slovak legislation (peroxide value - not more than 10 mEq O2.kg-1, acid value - not more than 0.6 mg KOH.g-1). However, detected values varied during deep-frying process. Monounsaturated fatty acids were predominantly observed in fresh rapeseed oil (61.22%) wherever in sunflower oil they were much lower (29.77%). A slight increase of MUFA was found in both oils. The initial content of saturated fatty acids in rapeseed oil was 6.94%, in fresh sunflower oil was observed slightly higher content of SFA (10.37%). The major groups of fatty acids in fresh sunflower oil were polyunsaturated fatty acids (PUFA) which have in principle a significant effect on oil deterioration. A slight decrease of PUFA was observed in both oils throughout the frying period. The content of PUFA was reduced by about 9.42% in rapeseed oil and by 10.8% in sunflower oil. The initial content was 28.14% and 58.91%, respectively.

Fish Oil Enzymatic Esterification for Acidity Reduction

The reduction of the fish oil acidity is a significant problem in the rendering industry, as the oil’s range of applications and market value strongly depend on this parameter. In particular, the lower the acidity, the larger the oil’s market value. This work aims to study the potential of enzymatic esterification for reducing the fish oil acidity, by converting the free fatty acids into esters. Thus, four commercial lipases were used and a parametric study was performed to identify the best operating conditions, varying the reaction temperature, enzyme/oil mass ratio and alcohol/FFA mass ratio. All experiments were performed in duplicate with a very good reproducibility of results. Results showed that Lipozyme TL 100L contributed to greater acidity reduction (75% from an initial acid value of 10–14 mg KOH/g oil) for esterification at 40 °C, using ethanol 96% v/v, enzyme/oil and alcohol/FFA mass ratios of 0.01 and 3.24 w/w, respectively, reaching 3.13 mg KOH/g oil of final acid value or 1.57% FFA content. The reaction kinetics were also studied and it was found that a second order rate law as a function of the alcohol and oil concentrations is more adequate, with 35.44 kJ/mol of activation energy and 1.94 × 103 L mol− 1 min− 1 of pre-exponential factor. In conclusion, this work shows that the enzymatic esterification to reduce the fish oil acidity is technically feasible, increasing its market value.

Adaptive neuro-fuzzy inference system-genetic algorithm vs. response surface methodology: A case of optimization of ferric sulfate-catalyzed esterification of palm kernel oil

Abstract Ferric sulfate-catalyzed esterification process for palm kernel oil (PKO), which had an initial acid value (AV) of 22 ± 0.1 mg KOH/g oil, was modeled using response surface methodology (RSM) and adaptive neuro fuzzy inference system (ANFIS). The process parameters investigated in the AV reduction of the oil were methanol-to-oil ratio (2:1–3:1), catalyst loading (6–10 w/v) and reaction time (15–25 min) using Box Behnken design of RSM. The developed ANFIS and RSM models were both subjected to various statistical evaluation and they both showed high degree of accuracy based on the high values of coefficient of determination ( R 2 ) of 0.9662 and 0.9039 for ANFIS and RSM, respectively and low values of mean absolute error of prediction (MAE) 0.0506 and 0.1506, and average absolute deviation (AAD) of 2.3665 and 7.1179 for ANFIS and RSM, respectively. To minimize the AV for the PKO, the process parameters investigated were optimized using RSM and ANFIS coupled with genetic algorithm (GA). Optimum values of methanol-to-oil ratio of 2.96:1, catalyst amount of 6 w/v and reaction time of 15 min with a corresponding AV of 1.05 mg KOH/g oil (95.2% AV reduction) were established using ANFIS-GA, while the values obtained using RSM were methanol-to-oil ratio of 2:1, catalyst amount of 6 w/v and reaction time of 25 min with a corresponding AV of 1.54 mg KOH/g oil (93.0% AV reduction). Based on the statistical indicators employed for this work, ANFIS was a better prediction tool than RSM while GA outperformed RSM in the optimization of the esterification process. Ferric sulfate proved to be a good catalyst for PKO esterification.

Intensification of esterification of non edible oil as sustainable feedstock using cavitational reactors

Using sustainable feed stock such as non-edible oil for the biodiesel production can be one of the cost effective approaches considering the ever growing interest towards renewable energy and problems in existing approaches for production. However, due to the high free fatty acid content, non-edible oils require considerable preprocessing before the actual transesterification reaction for biodiesel production. The present work focuses on intensification of the esterification reaction used as preprocessing step based on acoustic and hydrodynamic cavitation also presenting the comparison with the conventional approach. Karanja oil with initial acid value as 14.15mg of KOH/g of oil has been used as a sustainable feedstock. Effect of operating parameters such as molar ratio, catalyst loading, temperature and type of catalyst (sulfuric acid and Amberlyst-15) on the acid value reduction has been investigated. The maximum reduction in the acid value (final acid value as 2.7mg of KOH/g of oil) was obtained using acoustic cavitation at optimum molar ratio of oil to methanol as 1:5 and 2% sulfuric acid loading at ambient temperature. In the case of hydrodynamic cavitation, acid value reduced upto 4.2mg of KOH under optimized conditions of first stage processing. In the second stage esterification using hydrodynamic cavitation and conventional approach, the final acid value was 3.6 and 3.8mg of KOH/g of oil respectively. Energy requirement analysis for ultrasound and conventional approaches clearly established the superiority of the ultrasound based approach. The present study clearly demonstrated that significant intensification benefits can be obtained in terms of the reduction in the molar ratio and operating temperature for the case of acoustic cavitation as compared to the conventional approach with somewhat lower effects for the hydrodynamic cavitation.

Impact of High-Cut-Off Dialysis on Renal Recovery in Dialysis-Dependent Multiple Myeloma Patients: Results from a Case-Control Study.

BackgroundHigh-cut-off hemodialysis (HCO-HD) can effectively reduce high concentrations of circulating serum free light chains (sFLC) in patients with dialysis-dependent acute kidney injury (AKI) due to multiple myeloma (MM). Therefore, the aim of this study was to analyze renal recovery in a retrospective single-center cohort of dialysis-dependent MM patients treated with either conventional HD (conv. HD) or HCO-HD.Methods and ResultsThe final cohort consisted of 59 patients treated with HCO-HD (n = 42) or conv. HD (n = 17). A sustained sFLC response was detected in a significantly higher proportion of HCO-HD patients (83.3%) compared with conv. HD patients (29.4%; p = 0.007). The median duration of sFLC required to reach values <1000 mg/l was 14.5 days in the HCO-HD group and 36 days in the conv. HD group. The corresponding rates of renal recovery were 64.3% and 29.4%, respectively (chi-squared test, p = 0.014). Multivariate regression and decision tree analysis (recursive partitioning) revealed HCO-HD (adjusted odds ratio [OR] 6.1 [95% confidence interval (CI) 1.5–24.5], p = 0.011) and low initial uric acid values (adjusted OR 1.3 [95%CI 1.0–1.7], p = 0.045) as independent and paramount variables associated with a favorable renal outcome.ConclusionsIn summary, the results from this retrospective case-control study suggest in addition to novel agent-based chemotherapy a benefit of HCO-HD in sFLC removal and renal outcome in dialysis-dependent AKI secondary to MM. This finding was especially pertinent in patients with low initial uric acid values, resulting in a promising renal recovery rate of 71.9%. Further prospective studies are warranted.

Ultrasound assisted two-stage biodiesel synthesis from non-edible Schleichera triguga oil using heterogeneous catalyst: Kinetics and thermodynamic analysis

Present work deals with the ultrasound-assisted biodiesel production from low cost, substantial acid value kusum (Schleichera triguga) oil using a two-step method of esterification in presence of acid (H2SO4) catalyst followed by transesterification using a basic heterogeneous barium hydroxide (Ba(OH)2) catalyst. The initial acid value of kusum oil was reduced from 21.65 to 0.84mg of KOH/g of oil, by acid catalyzed esterification with 4:1 methanol to oil molar ratio, catalyst concentration 1% (v/v), ultrasonic irradiation time 20min at 40°C. Then, Ba(OH)2 concentration of 3% (w/w), methanol to oil molar ratio of 9:1, ultrasonic irradiation time of 80min, and temperature of 50°C was found to be the optimum conditions for transesterification step and triglyceride conversion of 96.8% (wt) was achieved. This paper also examined the kinetics as well as the evaluation of thermodynamic parameters for both esterification and transesterification reactions. The lower value of activation energy and higher values of kinetic constants indicated a fast rate of reaction, which could be attributed to the physical effect of emulsification, in which the microturbulence generated due to radial motion of bubbles, creates an intimate mixing of the immiscible reactants causing the increase in the interfacial area, giving faster reaction kinetics. The positive values of Gibbs-free energy (ΔG), enthalpy (ΔH) and negative value of entropy (ΔS) revealed that both the esterification and transesterification were non-spontaneous, endothermic and endergonic reactions. Therefore, the present work has not only established the escalation obtained due to ultrasonication but also exemplified the two-step approach for synthesis of biodiesel from non-edible kusum oil based on the use of heterogeneous catalyst for the transesterification step.

Biodiesel production from tannery fleshings: Feedstock pretreatment and process modeling

During raw hide processing, tanning industries generate large quantities of wastes containing a considerable amount of fat which can be converted into biodiesel. A typical representative of such wastes is fleshings – which however, usually contains a significant amount of free fatty acids, proteins and other impurities. Pretreatment was suggested as a means of processing this acidic feedstock, thereby enabling the reduction of the free fatty acid content under the limit value of 0.5% w/w when the alkali catalyst is then appropriate for transesterification. The feedstock pretreatment process involved the refining melting of fresh pigskin fleshings with subsequent extraction using a methanol or methanol solution with an equimolar amount of alkali i.e. tetramethylammonium hydroxide, isopropylamine and cyclohexylamine. A mathematical model of the pretreatment process was proposed, verified and used in further simulation calculations – which confirmed that deacidification employing methanolic alkali solutions is more efficient than pretreatment with pure methanol; in addition, the free fatty acids can be removed to the demanded level in just one step (fat initial acid value=20mgKOH/g, mass ratio of methanol to oil=1.5). The fat pretreated by the suggested procedure was used for alkali catalyzed transesterification. The prepared biodiesel met most of the EN 14214 requirements with respect to the limitations caused by the used fleshings fatty acid profile.

Use of Phagotrophic Microalga Ochromonas danica to Pretreat Waste Cooking Oil for Biodiesel Production

AbstractIn this study, the feasibility of pretreatment and/or upgrading of waste cooking oil (WCO) using the microalga Ochromonas danica was investigated. Two WCO samples with initial acid values (AV) of 10.7 mg KOH/g (~5.4 % FFA content) and 3.9 mg KOH/g (~2.0 % FFA content) were examined. The algal cells engulfed oil droplets and grew rapidly on both WCO samples. The cell growth rates on WCO were compared with the rates on olive oil, with or without surfactant addition to make the oil droplets smaller and easier for algal ingestion. Comparison was also made with the growth rate in a sugar‐based medium. More importantly, contacting the WCO with the phagotrophic O. danica cells was found to decrease the acid values of the remaining oil by 2.8 and 2.4 mg KOH/g WCO, respectively. The O. danica‐pretreated WCO, with lower acid values, are potentially better feedstock for biodiesel production.

Changes in the content of canolol and total phenolics, oxidative stability of rapeseed oil during accelerated storage

An oil sample was prepared by cold‐pressing from untreated (UTRO) and microwave‐treated (MWRO) rapeseed, and tertiary butyl‐hydroquinone (TBHQ) was added to another oil from untreated rapeseed. Microwave pretreatment significantly increased the total phenolics and canolol contents, as well as the initial acid value (AV), peroxide value (PV), and p‐anisidine value (pAV) of oil (p&lt;0.001). However, there was found to be a difference in the rate of increase of AV, PV, and pAV of oil during the autoxidation with the following order of all these values observed: UTRO &gt; UTRO + TBHQ &gt; MWRO. During storage, significant linear correlations (p&lt;0.001) were found between the PV, pAV, and canolol content (PV vs. Canolol = −0.960 to −0.890; pAV vs. Canolol = −0.889 to −0.968), and the DPPH activity was also linearly and significantly correlated with the content of total phenolics and canolol in oils. (DPPH vs. Tatal phenolics = 0.910–0.945; DPPH vs. Canolol = 0.941–0.962; p&lt;0.001). When the autoxidation test was completed (on the 10th wk), it was found that the contents of canolol and total phenolics in MWRO were the highest, followed by UTRO + TBHQ, and UTRO. These results indicate that the MWRO exhibited superior oxidative stability.Practical application: Canolol, also known as vinylsyringol, is a phenolic compound that has been identified as a decarboxylation product of sinapic acid, and this type of compounds is known for scavenging free radicals. In this study, we evaluated the changes occurring during storage in the contents of canolol and the total phenolics, oxidative stability, and antioxidant capacity of rapeseed oil and found good correlation among the canolol content, oxidative stability, and antioxidant capacity. Therefore, we can use canolol as a native antioxidant for rapeseed oil production in the future.Canolol in rapeseed and rapeseed oil that is formed by thermal decarboxylation of sinapic acid under microwave irradiation. Canolol formation has been shown to improve the oxidative stability of oil from microtreated rapeseed. The results showed a very good correlation between the level of primary oxidative products (peroxide values), secondary oxidative products (p‐anisidine values) and the contents of canolol in the rapeseed oil during storage. So, canolol has potential applications in oil storage.

Impact of Canolol‐Enriched Extract from Heat‐Treated Canola Meal to Enhance Oil Quality Parameters in Deep‐Frying: a Comparison with Rosemary Extract and TBHQ‐Fortified Oil Systems

AbstractCanolol‐enriched extracts obtained from the extraction of fluidized bed treated canola meal with supercritical carbon dioxide were added to high‐oleic canola oil in different concentrations (200, 500 and 750 mg/kg). After 30 h of deep‐fat frying, oils fortified with canolol‐enriched extracts showed a two to three times better frying performance in comparison to the commonly used antioxidants (TBHQ, 200 mg/kg; rosemary extract, 40 and 200 mg/kg) and a control without antioxidants with regards to the formation of di‐ and polymer triacylglycerols, total polar compounds, secondary degradation products (anisidine value) and the iodine value. The canolol‐enriched extracts were also able to slow down the degradation of α‐ and γ‐tocopherol during frying resulting in significant amounts of tocopherols after 30 h of frying in comparison to the other oils. The influence of the canolol‐enriched extracts indicated strongly concentration‐dependent performance. With increasing concentration of the extract, the thermal stability of the fortified oil was improved. The only disadvantage of the addition of the extracts was an increase in the initial acid value, but within the frying time, only oil fortified with 750 mg canolol‐enriched extract/kg reached the limit given in different countries.

Ultrasound assisted transesterification of high free fatty acids karanja oil using heterogeneous base catalysts

In present study, production of fuel-quality biodiesel from high free fatty acid (FFA) feed stock, such as karanja oil, was investigated by ultrasonic assisted technique using dual step process. The initial acid value of oil was found to be 33 mg KOH/g corresponding to FFA level of 18 %, which was far above 1 % limit for satisfactory transesterification reaction using alkali catalyst. Hence, the dual-step process, H2SO4 catalyzed esterification followed by transesterification in the presence of heterogeneous base Ba(OH)2·8H2O catalyst was performed with ultrasonic technique at 30 kHz and amplitude 80 %. In the esterification step, effect of different operating parameters such as alcohol to oil molar ratio (6:1–12:1); catalyst loading, H2SO4 (0.5–1.5 %); reaction time (30–120 min); and temperature (30–60 °C) to reduce the FFA content was investigated. In the second step, heterogeneous Ba(OH)2·8H2O catalyzed transesterification of acid esterified oil was carried out by studying the effects of following variable on maximum conversion level: the concentrations of Ba(OH)2·8H2O catalyst, reaction time, temperature, and alcohol to oil molar ratio. The product conformation was done using 1H-NMR (proton nuclear magnetic resonance). The physicochemical properties were determined and compared with the biodiesel standards. In addition, thermo-oxidative stability and cold flow properties of karanja oil and its methyl ester were also investigated.

Preparation and Characterization of Musa balbisiana Colla Underground Stem Nano-material for Biodiesel Production Under Elevated Conditions

A high free fatty acid (FFA) containing Jatropha curcas L. oil (JCO) was used for biodiesel production using Musa balbisiana Colla underground stem (MBCUS) ash catalyst, in a high pressure–high temperature (HT) reactor. The composition of the MBCUS catalyst was ascertained using XRF analysis and found that the ash obtained at 550 °C contain about 36 % silica (SiO2), 25 % potassium oxide (K2O), 10 % each of lime (CaO) and magnesia (MgO) and 4 % each of phosphorous pentoxide (P2O5) and alumina (Al2O3) as the major component for catalytic activation. The catalyst was characterized by SEM–EDX image analysis and found that the composition of the catalyst is versatile and consist of several alkali and alkaline earth metal chlorides, oxides, carbonate and silica. The BET surface area was found to be about 39 m2/g. The catalyst was further calcined in a TGA and observed that a maximum of 10 % losses were possible at 991 °C. The catalyst structure was further characterized from TEM images and found that the structural dimensions are identical (less than 100 nm length) and brick like (70 nm × 20 nm × 15 nm). The catalyst was found very effective during transesterification under HT (275 °C) and internal pressure (4.2 MPa) and 98.0 % fatty acid methyl ester (FAME) could be obtained from JCO with an initial acid value (AV) 18.4 mg KOH/g. There was a drastic reduction of FFA (AV 3.4 mg KOH/g) in the FAME obtained. The reduction of FFA may be attributed to the HT and high internal vapour pressure of the reaction mixture that resulted conversion of FFA to FAME and water. The fuel properties of the FAME were analysed as per ASTM and EN-standards.

바이오디젤 생산을 위한 어유의 에스테르화 및 전이에스테르화 반응

본 연구에서는 유리지방산을 4% 포함한 어유로부터 바이오디젤을 제조하기 위해 산촉매를 이용한 에스테르화 반응과 염기촉매를 이용한 전이에스테르화 반응을 수행하였다. 실험에 사용된 어유는 GS바이오사(社)로부터 공급받은 베트남산 메기(catfish)에서 추출된 오일을 사용하였다. 에스테르화 반응에 대하여 불균질계 고체 산촉매로 Amberlyst-15와 Amberlyst BD-20을 이용하였으며 균질계 산촉매로 황산을 사용하였다. 에스테르화 반응에 의한 유리지방산 제거율이 가장 높은 촉매는 황산으로 나타났으며 반응시간도 가장 짧게 나타났다. 3종의 염기촉매 KOH, <TEX>$NaOCH_3$</TEX>, NaOH를 이용하여 어유의 전이에스테르화 반응 특성을 조사한 결과 KOH 촉매가 가장 적합한 것으로 나타났다. <TEX>$NaOCH_3$</TEX>와 NaOH 촉매의 경우 전이에스테르화 반응시 글리세롤과 바이오디젤이 일정한 조건에서 고형화 현상이 관찰되었으며 비누화 반응이 진행된 것으로 판단된다. KOH 촉매를 이용하여 초기 원료 산가와 메탄올 투입량이 전이에스테르화 반응에 미치는 영향을 조사한 결과 초기 원료오일의 산가는 낮을수록 좋았으며 메탄올과 오일의 몰비는 9:1이 적합한 것으로 도출되었다. To produce biodiesel efficiently from fish oil containing 4% free fatty acid, esterification and trans-esterification were carried out with Vietnam catfish oil, which was kindly provided from GS-bio company. Heterogeneous solid acid catalysts such as Amberlyst-15 and Amberlyst BD-20 and sulfuric acid as homogeneous acid catalyst were used for the esterification of free fatty acids in the fish oil. Sulfuric acid showed the highest removal efficiency of free fatty acid and the shortest reaction time among three acid catalysts. The base catalysts for trans-esterification such as KOH, <TEX>$NaOCH_3$</TEX> and NaOH were compared with each other and KOH was determined to be the best transesterification catalyst. Some solid material, which assumed to be saponified product from glycerol and biodiesel, were observed to form in the fish oil biodiesel when using <TEX>$NaOCH_3$</TEX> and NaOH as the transesterification catalyst. The initial acid value of fish oil was proven to have a negative effect on biodiesel conversion. Of the three catalysts, KOH catalyst transesterification was shown to have high content of FAME and the optimal ratio of methanol/oil ratio was identified to be 9:1.

BIODIESEL PRODUCTION FROM WASTE COOKING OIL USING HYDRODINAMIC CAVITATION

The aim of this research was to study biodiesel production from low cost feedstock of waste cooking oil (WCO) using hydrodynamic cavitation apparatus. A two-step processes esterification process and transesterification process using hydrodynamic cavitation for the production of biodiesel from WCO is presented. The first step is acid-catalyzed esterification process for reducing free fatty acid (FFA) content of WCO and followed by base-catalyzed transesterification process for converting WCO to biodiesel as the second step. The result of esterification process with methanol to oil molar ratio of 5 and temperature of 60 oC showed that the initial acid value of WCO of 3.9 mg KOH/g can be decreased to 1.81 mg KOH/g in 120 minutes. The highest yield of biodiesel in transesterification process of 89.4% obtained at reaction time of 150 minutes with methanol to oil molar ratio of 6. The biodiesel produced in the experiment was analyzed by gas chromatography-mass spectrometry (GC-MS), which showed that it mainly contained five fatty acid methyl esters. In addition, the properties of biodiesel showed that all of the fuel properties met the Indonesian National Standard (INS) No. 04-7182-2006 for biodiesel.

쌀누룩의 혼합비율을 달리한 고추장의 품질특성

The quality characteristics of kochujang added with additives of different ratios of rice-nuruk (at 1:0.7, 1:1.0, 1:1.3) were studied. The kochujang was stored for 8 weeks at <TEX>$20{\pm}3^{\circ}C$</TEX>. The brix tended to increase by increasing mixing ratio of rice-nuruk in all treatments. It increased rapidly up to 4 weeks fermentation and then showed a slight change after 6 weeks. The more mixing ratio of rice-nuruk increased, the more salinity of samples decreased. The initial pH value of kochujang was 5.08-5.10., however, the pH value decreased to 4.82-4.83 after an 8 weeks of storage period. The initial acid value was 0.66-0.68 and increased from 0.66-0.68 to 0.87-0.89. It had slight reduction phenomenon in the sixth week. As the aging period passed, chromaticity such as <TEX>$a^*$</TEX>- and <TEX>$b^*$</TEX>-values decreased gradually except for <TEX>$L^*$</TEX>-value. The moisture content of samples decreased gradually by adding rice-nuruk. but increased by passing an aging period. The initial amino nitrogen content of sample was 304-315 mg%. It increased to 399-442 mg% during the aging period. As the aging period passed, the total cell number increased from 6.81 log CFU/mL to 7.01 log CFU/mL in the fourth week and then steadily decreased to 6.66 log CFU/mL in the eight week. Results of sensory evaluation show that, as more rice-nuruk was added, the kochujang received a lower mark. There was no significant difference in flavor in all treatments. Color and sweetness with increasing amounts of rice-nuruk showed the lowest score. Saltiness rice-nuruk at the ratio of 1:1.0 was the highest at 6.22 points. Texture scores decreased with increasing amounts of the rice-nuruk Based on these results, the overall acceptability of the 1:0.7 rice-nuruk treatment which received the highest score is considered excellent.