Autoclave Heating Research Articles

Optimizing winged-bean meal through oven and autoclave heating as viable alternative for plant-based aquafeed

Winged-bean meal can serve as a substitute for soybean meal in plant-based fish feed, despite its trypsin-inhibitor properties, which can be alleviated through heating processes. This study aimed to explore the potential of winged-bean meal subjected to different heating methods, namely oven (110 °C for 30 minutes) and autoclave (121 °C for 30 minutes), based on proximate analysis and trypsin activity. The study applied three treatments with four replications: oven heating (O), autoclave heating (A), and control (without heating, E). All data were analyzed using analysis of variance and Duncan’s multiple range test to determine the best treatment. Data were also compared to the nutrient requirements of several cultured freshwater fish in Indonesia. Heating treatments improved in vitro trypsin activity (1300 units/O and 1135 units/A vs. 835 units) but reduced protein (29.05±1.96%/A and 31.73±1.52%/O vs. 35.17±0.38%) and moisture contents. Additionally, the O treatment met the standards for aquafeed protein content (27-45%) and potentially fulfilled the protein requirements for catfish (25-40%), Nile tilapia (30-35%), and Java barb (30-32%). Therefore, oven heating presents a viable candidate as an alternative plant-based aquafeed ingredient. Nevertheless, the in vivo application of winged-bean meal as an aquafeed ingredient should be further evaluated to determine whether heating treatment effectively enhances digestive activity, nutrient retention, and growth performance in target fish species.

Three accelerated methods based on microwave, hydrothermal and conventional heating in the green synthesis of selenium nanoparticles using garlic aqueous extract: Screening and characterization

Selenium nanoparticles (Se NPs) have unique biological characteristics, including anticancer, antioxidant and antimicrobial activities. Furthermore, the green synthesis of Se NPs using plant extracts, due to their natural reductant and stabilizer molecules, can intensify the process with minimal toxic effects on the human body and the environment. Se NPs have been synthesized using an aqueous extract of garlic and three accelerated heating methods based on microwave (800 W for 2.5 min), hydrothermal (temperature and pressure of 121 ºC and 1.5 atm, for 15 min) and conventional (at 150 ºC for 1 h) heating using a heater with stirring. Solution mixtures containing 20 mL of the prepared extract and 5 mL of sodium selenite solution (10 mM) were exposed to these three mentioned heating methods. Fourier transform infrared spectroscopy, UV-Vis spectrophotometry, dynamic light scattering analysis and transmission electron microscopy were used to assess characteristics of the formed Se NPs. The results showed that the fabricated Se NPs via microwave, autoclave and conventional heating methods had minimum particle size (107 nm) and polydispersity index (0.155), and maximum zeta potential (-38.7 mV) values. Furthermore, the spherical formed Se NPs using garlic extract and under microwave, conventional and autoclave heating methods had antioxidant activity of 44.2, 34.8 and 32.6 %, respectively. The formed Se NPs also indicated high antibacterial activity toward Escherichia coli and Staphylococcus aureus bacteria strains.

Resistant starch content of dual modification autoclaving‐cooling and pullulanase debranching on various carbohydrate sources: a systematic review

SummaryResistant starch has a low glycaemic index and is commonly used in functional food development. Resistant starch type III can be produced through the combination of enzymatic debranching and the hot and cold cycle method, which is known as autoclaving‐cooling. The study showed that the dual modification of autoclaving‐cooling and pullulanase debranching can increase the resistant starch content, but it also depends on the carbohydrate source and the condition during the modification process. The study aims to determine the effects of pullulanase debranching and autoclaving‐cooling on resistant starch levels through a systematic review approach and produced 17 studies with 124 data. This dual‐modification study showed that 93.5% of data experienced in resistant starch increase while 6.5% experienced a decrease in resistant starch. The factors that should be considered were cooling/heating temperature and cooling/heating time, the number of cycles, the modification process sequence and enzyme concentration as well as temperature and hydrolysis time. Pullulanase debranching and autoclaving‐cooling dual modification with the highest resistant starch content was found on the chestnut starch sample (64.60%) with autoclave heating process (120 °C, 30 min), followed by debranching process (9 U/g, 50 °C, 10 h) and stored at 4 °C for 24 h.

Potential application of Aspergillus terreus, as a biofactory, in extracellular fabrication of silver nanoparticles

Silver nanoparticles (AgNPs), due to their unique properties, such as high antimicrobial activity toward numerous microorganisms, have been widely used in various areas. In the present study, AgNPs were synthesized using mycelia extract of the Aspergillus terreus, a filamentous fungi strain with fast growth rate, under autoclave heating conditions (121 °C and 15 atm). Effects of two fabrication parameters including, amount of mycelia extract (5–7 mL) and heating time (10–20 min) on particle size of the fabricated AgNPs, as manifested in broad emission peak (λmax) of the solution containing AgNPs, were assessed. Obtained results shown that the formed sphere-shaped AgNPs using optimum amount of A. terreus extract solution (6 mL) and autoclave heating time (15 min), had λmax, particle size, polydispersity index and zeta potential values of 430 nm, 40 nm, 0.576 and + 0.7 mV, respectively. Furthermore, antibacterial activity of the resulted AgNPs indicated their high bactericidal effects toward Escherichia coli and Staphylococcus aureus.

Effects of alternatively used thermal treatments on the mechanical and fracture behavior of dental resin composites with varying filler content

The purpose of this study was two-fold: (i) to investigate whether the thermal treatment of direct dental resin composites (RCs) using microwave or autoclave heating cycles would modify the materials' strength as compared to the protocol without heating (control); and (ii) to compare the mechanical performance of direct and indirect RCs. Three RCs (from 3M ESPE) were tested: one indirect (Sinfony); and two direct materials (microhybrid – Filtek Z250; and nanofilled – Filtek Z350). Specimens from the direct RCs were prepared and randomly allocated into three groups according to the thermal treatment (n = 10): Control – no thermal treatment was performed; Microwave – the wet heating was performed using a microwave oven; and Autoclave – the wet heating was performed in an autoclave oven. The indirect RC was prepared following the instructions of the manufacturer. All materials were tested using flexural strength, elastic modulus, work of fracture (Wf), microhardness, and scanning electron microscopy (SEM) analyses. Data were analyzed with ANOVA and Tukey as well as Weibull analysis (α = 0.05). The thermal treatments tended to produce slight changes in the topography of direct RCs, especially by the autoclave’ wet heating. Overall, the physico-mechanical properties changed after thermal treatment, although this effect was dependent on the type of RC and on the heating protocol. Sinfony showed the lowest modulus and hardness of the study, although it was the most compliant system (higher work of fracture). The load-deflection ability was also greater for the indirect RC. Reliability of the tested materials was similar among each other (p > 0.05). In conclusion, the alternative thermal treatments suggested here may significantly influence some aspects of the mechanical behavior of dental resin composites, with negative effects relying on both the chemical composition of the restorative material as well as on the wet heating protocol used. Clinicians should be aware of the possible effects that additional wet heating of direct resin composites using microwave or autoclave thermal protocols as performed here could have on the overall fracture and mechanical responses during loading circumstances.

Extracellular Mycosynthesis of Antibacterial Silver Nanoparticles UsingAspergillus flavusand Evaluation of their Characteristics

Fungi extracellular synthesis of silver nanoparticles (AgNPs) using Aspergillus flavus mycelia extract was evaluated. Fourier transform-infrared spectroscopy revealed the presence of hydroxyl and amide I groups in the prepared fungi mycelia extract which those had key roles in the reduction of silver ions and stabilizing of the formed AgNPs. Response surface methodology (RSM) has been used to optimize and evaluate the effects of the prepared mycelia extract amount (5–7[Formula: see text]mL) and autoclave heating time (10–20[Formula: see text]min) on the particle size of the synthesized AgNPs. Obtained results revealed that the spherical mono-dispersed AgNPs with high stability were synthesized using 6[Formula: see text]mL of fungal mycelia extract and hydrothermally heating for 15[Formula: see text]min. At this obtained optimum synthesis conditions, broad emission peaks ([Formula: see text], mean particle size, concentration and zeta potential values for the fabricated AgNPs were 450[Formula: see text]nm, 44[Formula: see text]nm, 72[Formula: see text]ppm and [Formula: see text][Formula: see text]mV, respectively. The synthesized AgNPs also indicated high antibacterial activity against both Gram positive and negative bacteria.

Microwave-assisted extraction of chitosan from Rhizopus oryzae NRRL 1526 biomass

Microwave-assisted extraction (MAE) of chitosan from dried fungal biomass of Rhizopus oryzae NRRL1526, obtained by culturing on potato dextrose broth (PDB), was performed and the optimal conditions required were identified using statistical analysis for the first time in this study. This microwave-assisted extraction (MAE) was compared against the conventional autoclave assisted method of chitosan extraction. The full factorial experimental design was used to investigate the impact of operating parameters of MAE, microwave power (100 W–500 W), and duration (10 min–30 min), on alkaline insoluble material (AIM) yield, chitosan yield, and degree of deacetylation (DDA). The effect of operating conditions was then evaluated using full factorial data analysis and optimum condition for MAE of chitosan was identified using response surface methodology to be 300 W and 22 min. This optimum condition identified was then further evaluated and the chitosan obtained characterized. Higher chitosan yield of 13.43 ± 0.3% (w/w) of fungal biomass was obtained when compared to that obtained, 6.67% ± 0.3% (w/w) of dry biomass, for the conventional extraction process. MAE yielded chitosan of higher degree of deacetylation, 94.6 ± 0.9% against 90.6 ± 0.5% (conventional heating), but the molecular weight was observed to be similar to that obtained by using conventional autoclave heating. MAE of chitosan was observed to yield a higher quantity of chitosan when compared to conventional extraction process and obtained chitosan exhibited a higher degree of deacetylation as well as molecular weight. The lower energy consumption of 0.11 kW h for MAE (5 kW h for conventional process) and the concomitant reduction in the energy bill to 1.1 cents from 50 cents, in addition to the above results, show that microwave irradiation is a more efficient and environment-friendly means to obtain chitosan from fungal biomass.

Effects of heat treatment under low moisture conditions on the protein and oil in soybean seeds

The effects of autoclave and microwave heating on the protein and oil in soybean seeds were investigated under low moisture conditions. The nitrogen solubility index (NSI) decreased on heating. The reduction in the NSI was accompanied by an increase in the size and deformation of the oil bodies in the cellular tissue of soybean seeds. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis analysis revealed that lipoxygenase was susceptible to heat denaturation, but 7S and 11S globulins were only partially denatured. The partial denaturation of the proteins was confirmed by Fourier transform infrared spectroscopy measurements. The ratio of oil to protein peaks increased with increasing heating, suggesting the exudation of oil to the surface or outside of oil bodies. Microwave heating is more efficient in changing the oil distribution in soybean seeds than autoclave heating. On the other hand, the degree of protein denaturation is lower after microwave heating.

Experimental and theoretical study of polypropylene: Antioxidant migration with different food simulants and temperatures

Polypropylene is a synthetic plastic widely used in industry due to its low price and convenience. Although its wide applications, serious safety issues have been raised about toxic chemicals such as butylated hydroxytoluene (BHT) and pentaerythritol tetrakismethylene-(3,5-di-tert-butyl-4-hydroxyhydrocinnamate) (Irganox 1010) which may migrate from polypropylene packaging into foods. Here, the effects of severe processing conditions [autoclave heating (121 °C), microwave radiation (700 W), and freezer storage (−30 °C)] on migration behavior were confirmed. Mathematical models were used to estimate the migration behavior of these compounds, and the results were compared with data from real experimental analyses which were performed by high-performance liquid chromatography. Overall, the estimated values from the mathematical model were 1.5–2 times larger than the experimental values for all conditions, suggesting that the mathematical migration models provide reliable predictions of migration. Taken together, computational assessment of migration behavior may be an effective way to decrease the time and expense of food safety evaluations.

COMPLEX TECHNOLOGICAL AND BIOLOGICAL RESEARCH OF SOLUTIONS FOR PERITONEAL DIALYSIS

Objective: The purpose of our work was to conduct technological, analytical, and biological investigations and stability studies of peritoneal dialysis (PD) solutions containing glucose and sodium lactate in single-chamber containers.Methods: Different formulations of PD solutions were prepared and sterilized at a temperature of 121 °C during 15 m. UV-spectrophotometric determination was performed using purified water as a blank. The spectra of the solutions were run in the range of 220 to 400 nm for the identification of an absorption maximum (λmax) and measuring the absorbance at 228-230 nm and λmaxbefore and after heat sterilization. λmax of the most PD solutions after sterilization was found in the range of 273 to 281 nm. The potentiometric determination was done for pH measuring PD solutions before and after sterilization. Alternative analytical procedure of direct argent metric method was employed for fast measuring content of chloride ions. Viability of Vero cells was evaluated using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) test, neutral red (NR) uptake assay, and sulforhodamine B (SRB) test.Results: The results showed that the absorbance of the most laboratory batches of PD solutions augments significantly with increasing an autoclave heating time to the sterilization temperature and time of its cooling after sterilization. The longer these parameters, the higher is the absorbance at 228-230 and 273-281 nm indicating 3,4-dideoxyglucoson-3-en (3,4-DGE) and 5-hydroxymethylfurfural (5-HMF) contents, respectively. Glucose degradation is practically absent at short terms of heating and cooling an autoclave while sterilized samples are preserved sterile. Stability studies showed a significant decrease in the absorbance at 228-230 nm during storage with the achievement of a nadir and the following weak increase; an elevation or decrease in the absorption maximum; a substantial decline in the pH of the solution after sterilization and an insignificant pH decrease during storage. The viability of kidney cells was the highest in the SRB test and the lowest one was in the MTT test.Conclusion: The influence of sterilization regimes on the quality of conventional PD solutions and their stability during storage were studied. The highest cytotoxicity was detected in the MTT test, and the lowest one was done in the SRB test, indicating the largest vulnerability of mitochondria under the influence of PD solutions compared to the membranes permeability, functioning of kidney cell lysosomes and the ability of cells to synthesize proteins. Our studies could be useful in the context of planning development of PD solutions with the purpose of authorization and domestic manufacture of these solutions in low-and-middle-income countries.

Determine effect of pressure heating on carbohydrate related molecular structures in association with carbohydrate metabolic profiles of cool-climate chickpeas using Globar spectroscopy

Grain has been heat-processed to alter rumen degradation characteristics and improve nutrient availabilities for ruminants. However, limited study was found on internal structure changes induced by processing on a molecular basis. The objectives of this study were to use advanced vibrational molecular spectroscopy to: (1) determine the processing induced carbohydrate (CHO) structure changes on a molecular basis, (2) investigate the effect of pressure heating on changes of CHO chemical profiles, CHO subfractions in cool-climate CDC Chickpea varieties, and (3) to reveal the association between carbohydrates related molecular spectra with carbohydrate metabolic profiles. The cool-climate CDC chickpea varieties with multisource were pressure heated in an autoclave at 120 °C for 60 min; and FTIR vibrational spectroscopy was used to detect the molecular spectra. Molecular spectroscopic results showed that compared to raw chickpea varieties, autoclave heating induced changes in both total CHO (region and baseline ca. 1186–946 cm−1) and structural CHO (STCHO, region and baseline ca. 1482–1186 cm−1), except for cellulosic compounds (CELC, region and baseline ca. 1374–1212 cm−1). The CHO chemical profile and rumen degradation results showed that autoclave heating decreased rumen degradable, undegradable and intestinal digestible sugar (CA4) content, but increased available fiber (CB3) content, without affecting available energy of chickpeas. The changes of CHO molecular spectra in chickpea varieties were strongly correlated with CHO chemical profiles, CHO subfractions, and CHO rumen degradation characteristics. Moreover, the regression analysis showed that STCHO peak 1 height could be used to predict sugar content, its rumen degradability and digestibility of chickpeas. Our results suggest that autoclave heating markedly changes sugar and fiber degradation characteristics. The carbohydrate molecular spectral profiles are associated with carbohydrate metabolic profiles in raw and pressure heated cool-climate chickpeas.

Evaluation of the saponin green extraction from Ziziphus spina-christi leaves using hydrothermal, microwave and Bain-Marie water bath heating methods

AbstractSaponin as a biosurfactant was extracted from IranianZiziphus spina-christileaves using three green extraction methods namely, autoclave, microwave and Bain-Marie heating methods. In this study, three solvents namely, methanol, ethanol and water were used to extract saponin. The results revealed that water, as compared to the methanol and ethanol, is a more suitable solvent to extract saponin from theZ. spina-christileaves. The obtained results indicated that saponin extraction using autoclave provided more suitable physico-chemical properties along with a better yield. In fact, maximum foam volume (12.56 cm3), color intensity (3.24% absorbance unit [a.u.]) and turbidity (1.39% a.u.) of the extracted solutions was obtained by the autoclave heating method. The high performance liquid chromatography (HPLC) results also illustrated that the amounts of extracted saponin using autoclave, Bain-Marie and microwave heating extraction methods were 14, 8.8 and 1.3 (intensity mV), respectively. The results obtained by HPLC were reconfirmed by Fourier transform infrared (FT-IR) analysis.

Migration Study of Butylated Hydroxytoluene and Irganox 1010 from Polypropylene Treated with Severe Processing Conditions.

The antioxidants with hydrophobic nature such as butylated hydroxytoluene (BHT) and Irganox 1010 (I-1010) in polypropylene sheets would be migrated to foods, which is an important issue for industrial production food packaging materials. Migration behavior was promoted by severe processing conditions such as autoclave heating, microwave radiation, freezing, and especially autoclave heating treatment led the highest migration among them. Therefore, control of chemical additive migration from polypropylene food packaging is needed for safe food processing.

Effects of heat processing methods on protein subfractions and protein degradation kinetics in dairy cattle in relation to protein molecular structure of barley grain using advanced molecular spectroscopy

The objectives of this study were: (1) to investigate the effect of three different heat processing methods on chemical profile, CNCPS protein subfraction, rumen degradation characteristics, and protein molecular structure of barley grain (CDC Meredith) using Fourier transform infrared attenuated total reflectance advanced molecular spectroscopy; (2) to detect association between protein degradation and availability and protein molecular structure profiles in dairy cows. The grains were kept as raw (control) or heated in an air-draft oven at 120 °C for 60min or in an autoclave at 120 °C for 60min or in a microwave at 900w for 5min. The results showed that autoclave heating decreased the ruminal effective degradability and increased the intestinal digestion of protein. The molecular spectroscopy was able to identify heating-induced changes in protein molecular structure, revealing that dry heating increased the amide I to II area ratio when compared with control. The α-helix to β-sheet ratio was greater in microwave heating than autoclave heating, suggesting protein damage in microwave-heated grains. The autoclave heating decreased the effective degradability of protein while increased the intestinal digestion of rumen undegradable protein. Protein subfractions, rumen degradable, undegradable and intestinal digestible protein fractions and degradation characteristics could be predicted by amide I area or α-helix.

A facile method for preparation of efficient oxygen reduction catalyst for a microbial fuel cell cathode

A facile preparation method for efficient oxygen reduction catalyst was suggested by examining three different approaches, which are microwave heating of a precursor solution (MS), dried precursor powder (MD), and autoclave heating of precursor solution (AS). The highest reduction peak current observed in (−0.034 mA) in cyclic voltammogram was obtained from the MS catalyst. However, the reduction peak current of the AS and the MD catalysts were 94.12% and 50%, of the MS catalyst, respectively. The surface with the MS catalyst consisted of small catalyst particles embedded in MWCNT strands, and its oxygen content was 4.67%, which was considerably lower than those of the surfaces (25.62∼38.86%) with the MD- and the AS catalysts, wherein large lump aggregations of catalyst compounds were observed. The MFC with MS catalyst cathode had very low activation and ohmic resistances (7.7Ω, 5.0 Ω) at maximum power density, and its MFC with the MS catalyst cathode were as low as 7.7Ω, 5.0 Ω, respectively, at maximum power density and it’s limiting current (19.6 mA) was considerably higher than the MD catalyst (2.75 mA) and the AS catalyst (10.2 mA) cathodes. The maximum power density of the MFC with MS catalyst cathode was 1,425 mW/m2, which was quite higher than those of the MFCs with MD catalyst (270 mW/m2) and AS catalyst (833 mW/m2) cathodes. This result shows that microwave heating (MS) of the catalyst precursor solution is the most feasible method for preparation of an efficient oxygen reduction catalyst for MFCs.

Nutritional and sensory quality of wheat bread supplemented with stabilized rice bran

This project was designed to evaluate the suitability of stabilized rice bran for the supplementation of bread. Freshly milled rice bran was treated with autoclave heating for its stabilization. The effect of stabilized rice bran supplementation on nutritional and sensory properties of wheat bread was determined. Blends of wheat flour and rice bran (95:5, 90:10, 85:15 and 80:20) were used to bake bread with 100 per cent wheat flour as control. Thereafter, proximate, mineral composition and sensory properties of the bread loaves were determined, using standard methods of analysis. The moisture content, crude protein, crude fat, crude fibre and ash of the composite bread loaves increased significantly (p < 0.05) from 31.12 per cent to 33.98 per cent, 11.87 per cent to 13.38 per cent, 1.52 per cent to 3.95 per cent, 0.82 per cent to 2.65 per cent and 1.52 per cent to 2.09 per cent, respectively; while carbohydrate content decreased with increased level of supplementation from 53.13 per cent to 43.92 per cent. Mineral content of the bread increased significantly (p < 0.05) with increased level of supplementation from 6.44 mg/100g to 15.61 mg/100g (Iron), 80.64 mg/100g to 221.22 mg/100g (Potassium), 84.47 mg/100g to 153.41 mg/100g (Calcium), 13.67 mg/100g to 161.86 mg/100g (Magnesium) and 2.24 mg/ 100gm to 4.13 mg/100g (Zinc). However, there was a significant decrease (p < 0.05) in sodium with increased level of supplementation from 304.31 mg/100g to 227.24 mg/100g. The control sample of bread was acceptable similar to 15 per cent rice bran supplemented bread. The bread supplemented with stabilized rice bran at 20 per cent got the lowest sensory score than other composite and control bread. But, all the composite bread samples had significantly (p< 0.05) higher values for nutritional parameters. It can be concluded from the results that upto 15 per cent stabilized rice bran can be successfully incorporated in the bread to improve the sensory and nutritional attributes.

Studies on the effect of stabilized rice bran supplementation on physico-chemical, microbial and textural quality of bread

This project was designed to evaluate the suitability of stabilized rice bran for the supplementation of bread. Freshly milled rice bran was treated with autoclave heating for its stabilization. The effect of stabilized rice bran supplementation on physico-chemical, microbial and textural quality of wheat bread was determined. Blends of wheat flour and rice bran (95:5, 90:10, 85:15 and 80:20) were used to bake bread with 100 per cent wheat flour as control. The physical properties of bread were evaluated and found that loaf weight increased with increasing per cent of rice bran flour into refined wheat flour. The loaf volumes of bread made from composite flour were lower than those made from control wheat flour. The effect of different levels of stabilized rice bran on crust and crumb colour of bread was evaluated. Results showed that lightness of crust and crumb of wheat bread gets decreased with increased level of stabilized rice bran. Also, redness (a) and yellowness (b) increased with increased level of stabilized rice bran. The proximate composition of the bread samples was analyzed. The moisture, crude protein, crude fat, crude fibre and ash contents increased significantly from 31.12 per cent to 33.98 per cent, 11.87 per cent to 13.38 per cent, 1.52 per cent to 3.95 per cent, 0.82 per cent to 2.65 per cent and 1.52 per cent to 2.09 per cent, respectively; with increased level of supplementation. The carbohydrate contents decreased with increased level of supplementation from 53.13 per cent to 43.92 per cent. The microbial properties shown that there was no significant difference in total plate count and yeast and mould count of functional wheat bread on increasing the supplementation of rice bran flour. The texture profile analysis showed that hardness and chewiness of functional wheat bread was increased with increase in supplementation of rice bran flour. There was no significant difference in springiness and cohesiveness of wheat bread supplemented with stabilized rice bran.

Mempelajari Ekstraksi Dan Stabilitas Total Karotenoid, Α dan Β Cryptoxanthin dalam Ekstrak Buah Merah (Pandanus Conoideus, Lamk

This aim of research was to find the optimum conditions for the extraction process of “buah merah” oil that produce optimum β-cryptoxanthin content. The treatments of extraction process are steaming at 80 0 C, autoclave at 121 0 C for 30 and 60 minutes respectely, and storing in refrigerator at -5 0 C for one night, then pressed and centrifugated. “Buah merah” oil produced from those treatments was tested for β-cryptoxanthin content. The “buah merah” oil with highest content of β-cryptoxanthin is conducted characteristics test based on water content, FFA, foreign matterial, PAHs and test for stability of total carotenoids, α and β cryptoxhantin of “buah merah” oil that stored in various conditions of temperature (4 0 C, 25 0 C, 35 0 C ), storage (dark and light using light flouresense lamp 10 W, type of packaging (brown glass bottle, soft capsules in PVC bottle), and extraction methods (traditional and modern). Observations was conducted every week.for 8 weeks The results showed that extraction process of “buah meraht”oil that produce of β-cryptoxanthin content with highest yield is extraction process using autoclave heating at 121° C for 1 hour that result 35% yield and 20.78% β-cryptoxanthin content. The type of packaging that resulted the best stability of consentration of total carotenoid α and β-cryptoxanthin in in the “buah merah” oil is packaging that use double package of capsule (primary packaging) and PVC bottle (secondary packaging) and store in dark condition with temperature of 4 ° C.

Effect of Microwave and Conventional Heating on the Cure Cycles of Particulate Reinforced Polymer Matrix Composites

Polymer composites by and large found suitable for many specific applications in the field of electrical, electronics, marine, aerospace and microelectronics. Thus a new technique for processing polymer composites has been explored and one such is microwave curing. The roles of microwave in the post curing of polymer matrix composites cannot be under estimated, as it has the capacity to reduce the undue lengthy cure cycle and also improve the mechanical properties of the composite produced. The aim of the study is to determine the effect of microwave post curing on the cure cycles of the unsaturated polyester composites reinforced with aluminum and carbon black. This effect was compared with that post cured using conventional oven with the objective of investigating the significance of microwave curing on the curing time of the produced composites. A specific study comprising of aluminum filled polyester based composite and carbon black filled polyester based composite were investigated using two different composite curing methods (microwave and conventional autoclave heating). The investigation, through experimentation was based on temperature profile in term of heating rate and cure characteristics in term of degree of cure of the produced composites. Comparing the results of the post-curing of the composites using microwave and conventional methods, 30% aluminum filled cured at 940C, 20% aluminum filled cure 920C, while 10% aluminum filled cured at 840C. Also, it took 20 minutes and 15 minutes for aluminium filled polyester and carbon black filled polyester composites respectively to reach ultimate cure in microwave system as compared to conventional autoclave system that takes the composite samples 290 minutes and 170 minutes respectively to get to the ultimate cure. It was concluded that post-curing of the particulate composites through microwave is able to achieve good heating rate and better control of temperature as compared to the conventional autoclave curing.

Modeling of Conventional Autoclave Curing of Unsaturated Polyester Based Composite Materials as Production Process Guide

Modeling of composite curing process is required prior to composite production as this would help in establishing correct production parameters thereby eliminating costly trial and error runs. Determining curing profile temperatures from experiment is a huge challenge which in itself is like re-inventing the wheel of trial and error, when mathematical models of physical, chemical and kinetic properties of the constituent materials could be used in modeling the cure situation to some degree of trust. This work has modeled two types of polymer based composite materials (Aluminum filled polyester and carbon-black filled polyester) representing polymer-metal and polymer-organic composites in order to predict the possible trends during conventional autoclave heating with regards to effect of heating rate on degree of cure of the composites. The numerical models were constructed by taking into account the heat transferred by conduction through the resin/filler mixture, as well as kinetic heat generated by cure reaction. The numerical solution of the mathematical models presented were discretized using forward finite differences of the Runge Kuta Method and finally solved using MATLAB® C programming language. It was observed that Aluminum filled polyester composite responded faster to heat input- induced curing and as such was able to cure faster than polyester –carbon black composite which had much slower cure –heat input response. This implies that in the production process of polymer-organic composites, faster heating rate was necessary to input heat into the process as there was no heat of reaction released during the cure process whereas, polymer-metal composites release heat of reaction contributing to the quick transfer of heat into the metal components causing the metal components to behave as points of adhesion to the polymer matrix thereby necessitating a slower heating rate.