Changes In Physicochemical Properties Research Articles

Effects of various pyrolysis temperatures on the physicochemical characteristics of crop straw-derived biochars and their application in tar reforming

As a by-product of the rapid pyrolysis of biomass, biochar not only plays an important role in the biomass conversion process but also holds significant potential value in the catalytic conversion field. This study aimed to evaluate the physicochemical properties changes of biochars at different pyrolysis temperatures and their potential application in tar reforming. Biochars derived from three feedstocks of maize straw (MS), rice husk (RH), and cotton straw (CS) were achieved by fast pyrolysis within a broad temperature range of 300~900 °C, respectively. The results showed that the pyrolysis temperature exerted a pronounced influence on the structural characteristics of biochar. With increasing temperature, the H/C and O/C ratios progressively decreased, accompanied by a significant reduction in oxygen-containing structures. In addition, elevated pyrolysis temperatures contributed favorably to the formation of the crystalline structure of biochar. Raman analysis unveiled a correlation between the fused aromatic ring system and H/C ratios, validating the aromatization progress of biochar. In the tar catalytic reforming process, the three representative biochars, under the effect of MS-600 (standing for MS biochar derived at 600 °C), RH-600, and CS-600 catalysts, exhibited outstanding catalytic performance with tar conversion efficiencies of 73.26%, 68.51%, and 71.43%, respectively. This study provided systematic support for the high-value use of biochar from crop straw.

Plant biomass partitioning in alpine meadows under different herbivores as influenced by soil bulk density and available nutrients

Biomass allocation is a key mechanism for understanding the response of alpine meadow plants to environmental changes. However, the two major theories of plant biomass partitioning, that is, optimal and equidistant allocation, are highly controversial. This study aimed to test these hypotheses by using the biomass allocation pattern of Qinghai–Tibetan Plateau alpine meadows under different herbivore assemblages and enclosures and to identify the key physicochemical factors driving changes in biomass allocation. The results showed that fencing and grazing lead to the allocation of more biomass to roots and shoots, respectively. Additionally, our results support the optimal allocation hypothesis, which is mainly regulated by changes in soil physicochemical properties. Specifically, the trade-off between aboveground- and belowground biomass negatively correlated with the soil bulk density, soil moisture, available nitrogen, and available phosphorus but positively correlated with available potassium. In terms of biomass trade-offs, co-grazing yaks and Tibetan sheep at a 1:6 ratio with moderate grazing intensity may be a reasonable method to use and protect alpine meadows on the Qinghai-Tibetan Plateau.

Changes in Nutrient Content and Physicochemical Properties of Cavendish Bananas var. Pei Chiao during Ripening

Banana is a typical tropical fruit that is widely cultivated in tropical and subtropical regions, and consumed daily because of its superior nutritional profile. This study aimed to investigate the changes in bananas’ physicochemical properties and nutritional composition from ripening stages 1 to 9. The analysis included color (peel and flesh), texture, total starch content, resistant starch content, free sugar content, minerals (calcium, magnesium, potassium, sodium, iron, phosphorus), and vitamin content. At the same time, the browning enzyme activities of polyphenol oxidase (PPO), peroxidase, oxalic acid, and tannin were also measured. In this study, the banana peel gradually changed from dark green to light green to yellow during the ripening process, eventually appearing with many black spots, while the pulp color changed from white to light yellow and decreased in brightness. The pulp became softer with a prolonged ripening period, which was inconsistent with the time point of peel color change (ripening period 4–5). However, total starch content decreased from 74% to 31%, resistant starch originally at 32% gradually decreased to 5%, and free sugar content gradually increased with increasing ripening period. Vitamin C content and PPO activity decreased significantly during the ripening period, while other vitamins and minerals did not change significantly. In contrast, oxalic acid, tannin content, and peroxidase activity were negatively correlated with the ripening period. Therefore, this study reveals the changes in the nutrient content of bananas at different ripening stages, which may provide helpful information for researchers and producers to identify suitable raw materials for producing stable and high-nutrition-value banana-related foods during the peak raw material abundance seasons while reducing business risk.

Investigation of long-term anti-sulfur and deactivation mechanism of monolithic Mn-Fe-Ce/Al2O3 catalysts for NH3-SCR: Changes in physicochemical and adsorption properties

Owing to the different reaction properties and deactivation mechanisms caused by the structural discrepancy of monolithic catalysts, abundant scientific results of powder or granular NH3-SCR catalysts have still not sufficiently robustly applied in recent years. Furthermore, minimal research has been focused on monolithic catalysts. As a result, this work prepared monolithic Mn-Fe-Ce/Al2O3 catalysts by active component impregnation (ACI-Mn-Fe-Ce/Al2O3) and precursor impregnation methods (PI-Mn-Fe-Ce/Al2O3) and investigates the long-term SO2 and H2O resistance of the catalysts. Compared with the PI-Mn-Fe-Ce/Al2O3 catalyst, the monolithic ACI-Mn-Fe-Ce/Al2O3 catalyst showed better performance. The catalytic activity follows a bell-shaped curve with an optimal performance at a drug loading of 5 %. The ACI-Mn-Fe-Ce/Al2O3 catalyst exhibits long-term resistance to SO2 and H2O and can still convert more than 70 % NOx after 168 h of SO2 and H2O resistance test. Characterization of the ACI-Mn-Fe-Ce/Al2O3 catalysts before and after the reaction showed that the reducibility decreased after the reaction, and more Mn4+ was transformed into Mn2+ to weaken the catalytic activity. However, more Fe2+ and Ce3+ were generated during the reaction, increasing the number of oxygen vacancies, oxygen defects, and hydroxyl-like groups, all of which would contribute to a certain extent to counteract the passivation effect of SO2 on the catalysts. In situ DRIFTs analysis shows that the formation of surface sulfates has a minimal effect on the adsorption of NO, but it does affect the adsorption of coordinated NH3 on Lewis acid sites. This work elucidates the deactivation details of Mn-Fe-Ce/Al2O3 catalysts from the perspective of physicochemical properties, which provides a reference for the development of better low-temperature SO2-resistance catalysts for industrial applications.

Multiple metabolite profiles uncover remarkable bioactive compounds and metabolic characteristics of noni fruit (Morinda citrifolia L.) at various stages of ripeness

This study aimed to investigate the changes in physicochemical properties, bioactive compounds, and metabolic characteristics of noni fruit at different ripeness levels. The results showed that there were significant differences in physicochemical properties. HPLC analysis was conducted, revealing succinic acid, scopoletin, deacetylasperulosidic acid, and asperulosidic acid were key bioactive compounds as the fruit ripened. Additionally, 4 different biomarkers (isocitric acid, 4,4-thiodiphenol, lobaric acid, and octocrylene), identified using 1H NMR and LC-IT-TOF-MS, were found to have a VIP value over 1. The results from HS-GC-IMS demonstrated noteworthy that 14 volatile compounds were identified as highly discriminative features during fruit ripening. Furthermore, correlation analysis showed that different ripeness had significant effects on bioactive components and functional activities, e.g., the inhibition rate of enzyme and E. coli of noni fruit with different ripeness exceeded 90% at the last stage. This study contributes new insights into the effective utilization of bioactive ingredients in noni fruit.

Impact of ultracentrifugal milling on the thermo-rheological, functional, and physicochemical properties of yellow and green pea flour

Pea seeds conversion into flour enhance their incorporation into diverse food systems. However, milling impacts changes in the flour's physicochemical and technofunctional properties. In this study, the impact of ultracentrifugal milling on the thermal, rheological, functional and physicochemical properties of flour from yellow and green pea varieties was investigated. Pea seeds were milled to maximum particle sizes of 0.25, 0.50 and 1.00 mm based on different screen aperture fitted to the ultracentrifugal mill. Scanning electron microscopy showed that flour samples milled with the 0.25 mm screen aperture had higher disentangled protein particles but more damaged starch particles compared to the 0.50 and 1.00 mm screens. The FTIR analysis indicated similar spectra with varying functional groups at corresponding wavelengths but different absorbance intensity. At 2853 cm−1 wavelength, additional peak for cellulose was detected in 0.25 mm milling condition but absent in other samples. Flour milled to 0.25 and 0.50 mm maximum particle size had the most desirable outcomes to rheological and thermal attributes. Principal component analysis score plots elucidated relationship between milling conditions, flour functionality and pea variety with PC1 at 46.64% and PC2 at 34.53%. These findings demonstrate that milling conditions can be a potential tool to manipulate pea flour functionality.

Impact of different sterilisation techniques on sorption and NER formation of test chemicals in soil

Standard OECD tests are used to generate data on biodegradation (OECD 307) and sorption (OECD 106) of test chemicals in soil. In such tests, data on abiotic degradation using sterile samples are utilised to investigate any losses due to abiotic processes. The data from sterile samples are also used to interpret results and findings of non-sterile samples, especially in the context of sorption and non-extractable residue (NER) formation. However, to ensure the comparability of the data obtained from sterile and non-sterile experiments, effects of sterilisation on the soil matrix should be minimal. The objective of this study was to investigate the efficiencies of different sterilisation techniques and the impact of the sterilisation on sorption and NER formation in soil. In this study, experiments in accordance with OECD 307 and OECD 106 guidelines were performed with two soils covering wide range of soil characteristics and treated with the three sterilisation techniques autoclaving, gamma(γ)-radiation and adding 1% (w/w) sodium azide. As a test item, 14C-labelled phenanthrene and bromoxynil was used for OECD 307 test, whereas non-labelled phenanthrene and atrazine was used for OECD 106. The sterilisation efficiencies were investigated using traditional viable plate count and molecular approaches (RNA extraction method). The results suggest that none of the tested techniques resulted in completely sterilised soil with autoclaving being the most efficient technique. Adding sodium azide led to most inefficient sterilisation and a significant increase (0.56 units) in soil pH. OECD 307 results showed differences in NER formation of the test chemicals, especially for soil poisoning and γ-radiation, which could be due to inefficient sterilisation and/or change in soil physico-chemical properties. OECD 106 results suggest that none of the sterilisation techniques considerably affected sorption behaviour of the test chemicals. Based on our results, we recommend autoclaving as most suitable sterilisation technique.

STUDY OF CHANGES IN THE PHYSICO-CHEMICAL PROPERTIES OF BELARUSIAN WHEAT GRAIN IN THE GERMINATION PROCESS

Wheat plays an important economic role as one of the main grain crops in the world. Its production and exports have a significant impact on the global economy.The main part of wheat grain consists of carbohydrates. They are mainly represented by starch (48-63 %). In addition to starch, grains contain 2-7% sugar (mainly in the germ), as well as 2-3 % fiber. The fat content in the embryo and the aleurone layer is 2 %. 1 kg of grain contains an average of 1.2 k units.The article presents the results of a comprehensive analysis of the grain of winter wheat of the "Dawn" variety. Based on the experimental data obtained, the viability and germination energy of the wheat under study was 84%, which means that this wheat sample is well suited for germination. Analytical dependences of changes in physico-chemical properties during germination are obtained. The results obtained allow us to analyze the changes that occur during the germination of wheat grains in the period from 1 to 48 hours. The data obtained indicate the promising use of wheat grain for further research and production of biologically active raw materials and its use for food purposes.

Variations in macrofaunal communities along sand physico-chemical gradient across the intertidal zones on island beaches

Island beaches, once mistakenly considered as 'ecological deserts', are actually unique ecosystems that support abundant macrofaunal communities. However, limited studies have examined the variations and determinants of macrofaunal communities across the intertidal zones on island beaches, which is crucial for shedding light on the underlying ecological processes and enhancing biodiversity conservation efforts. Here, we explored the variations in macrofaunal communities along sand physico-chemical gradient across four intertidal zones on nine representative beaches, within the largest land-bridge archipelago in eastern China. Our findings revealed that species richness, density, and Shannon-Wiener diversity of macrofaunal communities were notably higher in the lower intertidal zones, exhibiting a positive correlation with elevated levels of sand moisture (M), electrical conductivity (EC), available potassium (AK), and grain size (GS). Conversely, macrofaunal Simpson diversity displayed an inverse pattern, with heightened values observed in the vegetation zone. The Saprophagous, Predaceous, and Omnivorous groups of macrofaunal communities demonstrated an increase with higher levels of EC, AK, and M in the lower intertidal zones. Furthermore, Phytophagous group of macrofaunal communities tended to inhabit the vegetation zones characterized by elevated levels of sand total phosphorus (TP), total nitrogen (TN), and organic carbon (OC). Primarily, our findings indicate that sand nutrition, moisture, and salinity play pivotal roles in shaping the variations of macrofaunal communities on island beaches. These insights offer valuable perspectives into the holistic responses of macrofauna on island beaches to changes in sand physico-chemical properties, serving as a crucial theoretical foundation for the assessment, conservation, and restoration of island beaches.

Resistant starch formation and changes in physicochemical properties of waxy and non-waxy rice starches by autoclaving-cooling treatment

ABSTRACT Resistant starch (RS) has drawn great attention from both starch research and industrial communities due to its potential health benefits. Physical starch modification approach, such as autoclaving and cooling cycle treatment, offers high potential method of enhancing resistant starch fraction due to its simplicity and cost-effectiveness. Here, the non-waxy KDML105 and waxy RD6 rice starches were physically modified by one, three, and five autoclaving and cooling cycles. The comparative impacts of the modification on the RS content and starch physicochemical properties were examined. Their native starch granules were transformed into a larger continuous matrix with suppressed thermal and pasting properties. However, modified KDML105 starch gels with higher amylose content and the presence of amylose lipid complexes were able to retrograde and maintain viscosity better than the modified RD6 starch. The RS content was also increased with the addition of treatment cycles in KDML105 starch. As a result, the RS content of native KDML105 starch was enhanced from 0.13% to 2.59% after five cycles of the treatment. The dissimilarities observed between the two modified starches could be due to the different degrees of increased proportions of ordered (R1047/1022) and double helical (R995/1022) structures, and the disruption of A- and V-type crystals. Therefore, the RS content was attributed to an interplay of alterations in ordered structure, amylose, and amylose-lipid complex during autoclaving-cooling cycles.

Effect of Simultaneous Ultrasonication and Protease Treatment on Wet Milling of High‐Amylose Corn

AbstractThe objective of this work is to study the effect of applying simultaneous ultrasonication and alkaline protease treatment to the wet‐milling of high‐amylose corn on improving the starch yield and reducing the starch protein content. After applying the optimal conditions of simultaneous ultrasonication and protease treatment to the wet milling, the starch yield is elevated to 61.3% and the starch protein content is decreased to 0.44% when compared to the conventional process (48.9% and 1.75%, respectively). High‐amylose corn starch extracted using simultaneous ultrasonication and protease treatment has crystalline structure, relative crystallinity, pasting properties, thermal properties, and enzymatic digestibility similar to the one extracted from the conventional process. The results suggest that simultaneous ultrasonication and protease treatment are a friendly approach in improving the yield of high‐amylose corn starch and reducing the starch protein content, causing no obvious change in starch physicochemical properties and enzymatic digestibility. This study provides useful information for scaling up simultaneous ultrasonication and protease treatment to industrial scale with minor modifications of the conventional wet‐milling process.

Tailoring the physicochemical properties of starch: impact of integrated ultrasonic and ethanol pretreatment on the oil uptake of infrared fried ginkgo seeds.

The structural changes of starch would have a more crucial impact on oil absorption and quality changes in starch-rich fruits and vegetables during frying process with enhanced heat transfer (such as infrared frying). In the present study, the influence of integrated ultrasonic and ethanol (US + ethanol) pretreatment on oil uptake in infrared fried (IF) ginkgo seeds was evaluated regarding modifications in the physicochemical properties of starch. The pretreatment was performed with ultrasonic (40 kHz, 300 W) and ethanol osmotic (95%, v/v) treatment individually or integrated for 40 min. The mass transfer in the pretreatment was facilitated by combined ultrasound and ethanol. The swelling power, solubility, and gelatinization degree of starch was significantly increased. Low-frequency-NMR curves and images revealed that the bound water fraction in ginkgo seeds was increased and the water distribution was homogenized. The results of Fourier transform-infrared spectrum and differential scanning calorimeter revealed that the crystalline regions of starch were reduced and the thermal enthalpy was decreased after US + ethanol pretreatment. The total, surface and structural oil content in IF ginkgo seeds with US + ethanol pretreatment was reduced by 29.10%, 34.52% and 29.73%, respectively. The US + ethanol pretreatment led to a thinner crust layer with increased porosity and smaller-sized pores in the IF ginkgo seeds as observed by stereo microscopy and scanning electron microscopy. The changes in structural and physicochemical properties of starch by combined ultrasound and ethanol affect the crust ratio and pore characteristics in fried high-starch fruits and vegetables, thereby reducing oil absorption. © 2024 Society of Chemical Industry.

Exploring the influence of sweet potato powder on the physicochemical characteristics, oxidative potential and sensory perception of mayonnaise

SummaryReduced fat mayonnaise was prepared by substituting oil with sweet potato powder at concentrations of 2%, 4% and 6%. The changes in physicochemical, oxidative, rheological, microbial and organoleptic properties of functional reduced fat mayonnaise were investigated. The results revealed that sweet potato powder significantly improved the antioxidant activity (2.63–31.6%), rheological attributes, nutritional content and shelf life stability of mayonnaise during the storage time of 21 days. Rheological evaluation illustrated the stabilisation of samples with the addition of sweet potato powder, with a significant reduction in oil droplet size (6.78–2.16 μm) and an increase in firmness (0.941–1.84 N) and adhesiveness (41.21–76.78 × 10−3 Nm). Emulsion stability (93.3–99.2%) was significantly (P < 0.05) enhanced by supplementation with sweet potato powder. The presence of carotenoids in sweet potato improved colour and increased the L* (73.4%) and b* (31.4%) values. Preliminary sensory evaluation demonstrated that taste, texture, mouthfeel and overall acceptability were perceived better in the samples supplemented with sweet potato powder. Our findings suggest that sweet potato powder can be a nutrient enhancer and a considerable alternative to synthetic antioxidants and stabilisers for oil‐in‐water food emulsions.

ИССЛЕДОВАНИЕ ФИЗИКО-ХИМИЧЕСКИХ И ПРОТИВОИЗНОСНЫХ СВОЙСТВ МОТОРНЫХ МАСЕЛ ПО ЗАВЕРШЕНИИ ПРОЦЕССА ЭКСПЛУАТАЦИИ

There is given the study of viscous properties of engine oil, depending on the temperature before and after change on modern domestic gasoline and diesel cars, the determination of spectral characteristics and X-ray fluorescence analysis of wear particles after mileage. The degree of viscosity of semi-synthetic oils of two types is estimated. The oils were cooled and heated up to 150 °C. A digital viscometer was used, the dynamic viscosity of all oils decreased with increasing temperature, which is associated with oxidation in waste oil. To assess the effect of motor oil on engine operation, IR spectrometric analysis is performed and the thickness of the lubricating film is determined. The test results showed a qualitative and quantitative change in the characteristic frequencies of the new engine oil and the spent one after 10,000 km. X-ray fluorescence analysis makes it possible to analyze wear products and determine which mechanism in the engine is most susceptible to wear. Lines have characteristic absorption frequencies and indicate a change in physico-chemical properties of oil in the engine. An increase in contamination and in the viscosity of used oils is associated with the presence of impurities formed during the oxidation and polymerization of the base oil. It is necessary to increase the number of samples and sampling during different periods of operation so that you can verify the same effect throughout the entire engine operation. The results obtained indicate that these methods can be used to analyze and control the mode of operation of oils in the engine, allowing to determine the wear and further apply appropriate additives to the oil to improve performance properties.

Evaluation of Low-Pressure Cold Plasma Effect on Phytonutrients, Drying and Microstructural Characteristics, and Changes in Microbial Load of Fresh and Hot-Air-Dried ‘Heidi’ Mango

AbstractAlternative pre-treatment strategies before drying offer the prospect to minimize drying time, replacing the use of chemicals, and preserving quality of dried fresh products. This study explored the application of low-pressure atmospheric cold plasma (CP) for 5- and 10 min (CP5 and CP10) as pre-treatments prior to processing and hot air drying (60 °C) of ‘Heidi’ mango, while non-treated samples served as control. Changes in tissue microstructure and physicochemical properties, bioactive compounds, and microbial load were evaluated, and seven thin layer drying models were applied. Scanned electron microscope images showed that CP pre-treatments altered the tissue microstructure of dried mango slices compared to control. ‘Heidi’ mango slices with the initial moisture content of 80 ± 0.2% on a wet basis was reduced by 81% and 76% in dried CP5 and CP10 samples, respectively. Drying time was reduced by 20% for CP pre-treated samples in comparison to control samples, and the drying behavior of ‘Heidi’ mango slices was best described by the Logarithmic model (R2, 0.9999 and RMSE, 0.0122). Colour attributes were best retained by sodium metabisulphite (SMB) pre-treated samples, followed by CP5 pre-treated, which performed better than CP10 and control (p ≤ 0.05). Highest total flavanols (15.0 ± 0.4 mg CE 100 g−1) and higher total phenolics (1528.2 ± 23.6 mg GA 100 g−1) were found in CP5 pre-treated samples compared to the control (p ≤ 0.05). Lowest antioxidant activities were found in CP10 pre-treated samples compared to the control (p ≤ 0.05). CP-pretreatment and drying resulted in ≥ 2 Log reduction in microbial load on mango slices. These results demonstrate to the role players in mango value addition chain, the potential of low-pressure CP pretreatment in enhancing/maintaining the bioactive compounds, reducing drying time and microbial load.

Improvement of Saline Soil Properties and Brassica rapa L. Growth Using Biofertilizers

The decline in agricultural productivity because of soil salinization has become a global problem in recent years. Biofertilizers show great potential for soil improvement as a sustainable strategy; however, their effectiveness in improving saline soils and enhancing plant growth under saline stress is poorly understood. We assessed the effectiveness of biofertilizers in improving saline soils and enhancing crop growth under saline stress and investigated the related potential mechanisms. Changes in soil physicochemical properties, plant physiological parameters, and soil microbial communities were analyzed using pot experiments. The results showed that biofertilizer application reduced total soluble salts in the soil by 30.8% and increased Brassica rapa L. biomass by 8.4 times. Biofertilizer application increased soil organic matter, total nitrogen, and available phosphorus by 56.1%, 57.0%, and 290%, respectively. Simultaneously, superoxide dismutase, catalase, chlorophyll a, chlorophyll b, total soluble sugar, and proline levels also increased by 89.5%, 140%, 110%, 190%, and 130%, respectively. Biofertilizers increased the abundance of Bacillus and Planococcus and decreased the abundance of Mortierella and Aspergillus, which could potentially be the underlying reason for the promotion of plant growth. Overall, the results of this study demonstrate the efficacy of biofertilizers in improving saline soils and that the application of biofertilizer could greatly promote agricultural production.

Combined hydroxyphenyl-modified adhesive with the ion-pair strategy for long-lasting delivery of clonidine in single-layer matrix-type patch

Existing long-acting patches usually use controlled-release membranes to achieve constant rate delivery of the drug, which is complex and costly to prepare due to the 5-layer structure, so there is a necessity to develop a method to simplify the patch design and to control constant rate drug delivery. This study prepared a 7-day long-acting clonidine (CLO) patch using the ion-pair strategy based on hydroxyphenyl-modified pressure-sensitive adhesive (HP-PSA) and clarified the molecular mechanism of controlled delivery. Single factorial and central composite design (CCD) experiments were used to optimize the patch formulation, which was evaluated by a pharmacokinetic study. The controlled drug delivery mechanism was investigated by FTIR, 1H NMR, differential scanning calorimetry (DSC), confocal laser scanning microscopy (CLSM), molecular modeling, and rheology study. The optimized patch was formulated with 4.80% (w/w) CLO-AA (azelaic acid) as API and HP-PSA as PSA matrix and 95.00 μm thickness. The single-layer patch not only simplifies the preparation process but also has a zero-level skin penetration profile (r = 0.9592) in vitro. Compared with the commercial patch (AUC0-t = 7748.51 ± 662.76 h ng/ml, MRT0-t = 71.04 ± 9.30h), the pharmacokinetic behavior of the optimization group was semblable (AUC0-t = 8160.28 ± 694.04 h ng/ml, MRT0-t = 63.19 ± 12.38h). Mechanistic studies showed that ion-pair improved drug interaction with HP-PSA, leading to controlled drug release. Changes in drug physicochemical properties decreased skin permeability and increased drug-skin interaction, resulting in a constant delivery rate. In conclusion, the 7-day long-acting drug delivery of the CLO patch was achieved by the ion-pair strategy, which simplified the preparation process, and inspired a long-acting transdermal drug delivery system.

Effect of heating time on changes in physicochemical properties and fatty acid composition of red palm oil

Crude Palm Oil (CPO) contains approximately 50% saturated fatty acids and approximately 40% unsaturated fatty acids. Unsaturated fatty acid content is known to be effective in lowering blood cholesterol levels. Palm oil also contains -carotene which is very beneficial for health. Palm oil processing is defined by three stages, namely degumming, bleaching and deodorization. The bleaching process is carried out at 90–105oC using 1-2% bleaching earth and deodorization at 240-270oC. The high concentration of bleaching earth and deodorization temperature causes carotene to be degraded leading to low carotene content in the final product. The effort to maintain the carotene content is to process CPO into red palm oil (RPO). The content of carotene and fatty acids contained therein will be damaged in the presence of high heat, ascertain this, a study was conducted on the effect of heating time on the chemical properties of red palm oil. The study was conducted using a completely randomized block design with prolonged heating treatment (0, 2, 4, 6, 8 and 10 hours) at 180oC and repeated 3 times and then the fatty acid content, peroxide value, iodine number and functional groups formed in bulk red palm oil purchased online were observed. The results showed that increasing the heating time can decrease the iodine number but increase the acid number and peroxide value. Heating at 180oC for 10 hours produced iodine, acid and peroxide value of 57.72, 9.56 and 12.55, respectively. The results of the analysis using Fourier Transform Infra-Red (FTIR) showed the presence of free fatty acids at wave number 722 cm-1 and peroxide numbers at wave number 2.854 cm-1. The test results using gas chromatography showed that linoleic acid decreased by about 3.23% during heating for up to 10 hours, while saturated fatty acids increased by about 0.32%. Key words: Cooking oil, Free fatty acid, Iodine number, Peroxide number, polymerization

Changes in the Main Physicochemical Properties and Electrochemical Fingerprints in the Production of Sea Buckthorn Juice by Pectinase Treatment.

Enzymatic hydrolysis using pectinase is critical for producing high-yield and quality sea buckthorn juice. This study determined the optimal temperature, time, and enzyme dosage combinations to guide manufacturers. A temperature of 60 °C, hydrolysis time of 3 h, and 0.3% enzyme dosage gave 64.1% juice yield-25% higher than without enzymes. Furthermore, monitoring physicochemical properties reveals enzyme impacts on composition. Higher dosages increase soluble solids up to 15% and soluble fiber content by 35% through cell wall breakdown. However, excessive amounts over 0.3% decrease yields. Pectin concentration also declines dose-dependently, falling by 91% at 0.4%, improving juice stability but needing modulation to retain viscosity. Electrochemical fingerprinting successfully differentiates process conditions, offering a rapid quality control tool. Its potential for commercial inline use during enzymatic treatment requires exploration. Overall, connecting optimized parameters to measured effects provides actionable insights for manufacturers to boost yields, determine enzyme impacts on nutrition/functionality, and introduce novel process analytical technology. Further investigations of health properties using these conditions could expand sea buckthorn juice functionality.

Characterization of key aroma compounds in cold brew coffee prepared by negative-pressure extraction technology and its changes during storage

Cold brew coffee is gaining popularity among consumers; however, its extraction is time consuming and it has a short shelf life. This study employed negative-pressure extraction to reduce the extraction time of cold brew coffee. Ninety-four volatile compounds, including furans, ketones, pyrazines, esters, aldehydes, azoles, pyrroles, phenols, pyridines, acids, and alcohols, were identified. The concentrations of these compounds varied with the extraction time. Sensory evaluation revealed the optimal extraction time to be 5 h, significantly enhancing the extraction efficiency of cold brew coffee. At this point, 9 key aroma compounds (OAV ≥1) were identified, with 2,3-diethyl-5-methyl-pyrazine and 3-ethyl-2,5-dimethyl-pyrazine predominant in the sample. We also investigated the changes in the physicochemical properties and key aroma compounds of cold brew coffee during refrigerated storage. The results showed a significant increase in acidity and total acid content, a notable decrease in antioxidant activity, and a decline in key aroma compounds with the extension of storage time. These findings indicated that the deterioration of cold brew coffee might be caused by the degradation of aroma compounds, leading to changes in the coffee's physicochemical properties. This study provides theoretical support for accelerating the extraction of cold brew coffee and extending its shelf life.