Journal of the American Oil Chemists Society最新文献

Glycerol is produced on a large scale as a byproduct in the biodiesel market. In order to give an application to glycerol, this work uses diglycerol from synthesized polyglycerol and commercial triglycerol in the synthesis of long chain esters obtained from esterification and transesterification reactions with oleic acid, methyl oleate, and epoxidized methyl oleate. Diglycerol tetraoleate (DGMO), epoxidized diglycerol tetraoleate (DGEMO), and triglycerol pentaoleate (TGOA) were synthesized and characterized by ¹H and ¹³C Nuclear Magnetic Resonance (NMR) and infrared (IR) spectroscopy. Polyglycerol esters were evaluated for basic lubrication properties such as density, kinematic viscosity, viscosity index, melting point, and thermo-oxidative stability. The ester that showed best thermo-oxidative stability was DGEMO. In addition, the influence of esters synthesized as additives in a pure paraffinic oil lubricant was evaluated and the TGOA showed greater change in viscosity at 100 and 40°C and in melting point which was increased by 1.56°C.

This study investigated the effects of temperature and pressure on the yield and volatile compound contents of black cumin seed oil (BCO) extracted from black cumin seeds using supercritical carbon dioxide (SCCO₂). The solubility of BCO in SCCO₂ increased 2.5-fold as the pressure increased by 10 MPa. Major volatile compounds in BCO were identified using a static headspace gas chromatography–mass spectrometry (SH–GC–MS). Evidence indicated the main volatile components in SCCO₂-extracted BCO to be hexanal, p-cymene, and thymoquinone. BCO extracted from China-cultivated black cumin seed contained similar amounts of p-cymene and thymoquinone. This black cumin seed is classified as the cymene/thymoquinone chemotype and is also found in Indian, Iranian, and Algerian black cumin seeds. Thymoquinone contents in BCO were more sensitive to the extraction temperature than hexanal and p-cymene contents. The maximum oil yield of 36.28 ± 1.38 wt%, with approximately 2.0 mg of thymoquinone per milliliter of oil, was obtained at extraction temperatures of 50°C and pressures of 30 MPa. A SH–GC–MS could detect small molecules in black cumin seed oil such as hexanal. The results of this work reveal that temperature has more impact on the selectivity of volatile compounds than pressure in supercritical carbon dioxide extraction.

Washing crude epoxidized oil is an indispensable step for the removal of residual acetic acid and unreacted hydrogen peroxide after epoxidation. There are many studies on the epoxidation of vegetable oils but there are many discrepancies in the washing process which likely leads to water wastage, excess use of neutralizing agent, and additional processing time. Hence, this study aims to optimize the washing step by analyzing the quality of each washing step and developing a model that can predict the amount of acid removed. Soybean oil (1.5 kg) was epoxidized at 60°C for 5.5 h using Amberlite IR 120H as a heterogeneous catalyst. To determine the optimum water washing level, process parameters such as number of washing cycles (1–5), proportion of epoxidized oil to water volume (1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5), and water temperature (20, 40, and 60°C) were examined. The main responses were the residual acid value and pH of the washed epoxidized oil. Results revealed that 64% of the acid was removed after 5 washing cycles irrespective of the washing water temperature and proportion. In contrast, approximately 57% of the acid was removed in the first two washing cycles. Increasing the temperature of the water affected acid removal; with approximately 54% of acid removed at 20°C compared to 60% at 60°C. Doubling or tripling the amount of water needed above a 1:0.5 ratio did not significantly affect the amount of acid removed. The model developed was significant with a predicted R² of 96% and a root mean square error (RMSE) of 1.1 when the model was validated at different washing scenarios. Therefore, this study shows that it is possible to significantly reduce the amount of water used and processing time while maintaining resin qualities.

The content of phenolic compounds in chocolate depends on the processing of the cocoa from bean to bar. The aim of this study was to determine the fate of phenolic compounds and theobromine in cocoa beans during roasting at different temperatures. Based on a screening of 12 cocoa bean sorts, three beans (NM, NCC, and NB) with initial high total phenolic content (TPC) were selected for the roasting trial (100 and 150°C up to 20 min). The concentration of three major flavonoids ((−)-catechin, (−)-epicatechin and procyanidin B2) and one methylxanthine (theobromine) were evaluated in both raw and roasted beans. Results showed changes in the concentration of flavonoids and theobromine during roasting. Roasting at 150°C for 15 min was optimal for maintaining high flavonoid levels while reducing theobromine levels. However, sensory evaluation on final product is needed to confirm whether the suggested roasting condition would also result in a final product with pleasant sensory properties.

Biodiesel (fatty acid methyl esters [FAME]) is a renewable biomass-based diesel (BBD) fuel made from plant oils, animal fats and waste greases. One of the main disadvantages of biodiesel is its poor oxidative stability, which is caused by the presence of high concentrations of unsaturated FAME. When stored in fuel terminals, vehicle tanks and fuel systems, biodiesel can react with oxygen in ambient air, causing it to degrade, which can adversely affect its viscosity and ignition quality. The shelf-life (SL) of biodiesel is an important property that defines how long it can be stored at low temperatures. The objective of this work is to develop reliable mathematical models to estimate the SL of biodiesel at T = 25°C (298.15 K). This was done by measuring oxidation induction period with a Rancimat instrument (IP_R) at variable temperatures. The data were analyzed by linear regression to determine ln(IP_R) as a function of T (Model A) and T⁻¹ (Model B) for canola, palm and soybean oil FAME (CaME, PME and SME), methyl oleate (MeC18:1) and methyl linoleate (MeC18:2). Statistical analysis of the Model A and Model B type equations showed that all inferred equations were good fits of the experimental data (adjusted coefficients of determination, R² ≥ 0.985). The most dependable results were obtained from extrapolation of Model B type equations to predict the SL^B values. For CaME, PME, SME and MeC18:1, SL^B = 559.0, 1135, 378.3 and 4515 d were inferred. However, the reliability of SL^A (extrapolated from its Model A type equation) and SL^B values calculated for MeC18:2 (3.1 and 4.8 d) were questionable as estimates of its SL at 298.15 K.

The increasing global population, coupled with the effects of climate change on agricultural activities has spurred a demand for sustainable food production to meet human needs. In response to this, there has been a growing interest in sustainable food production initiatives. One of such initiatives is harnessing microbial and insect lipids as valuable ingredients to address increase in demand for lipids across various sectors, including functional food, nutritional supplements, and biodiesel production. Over the last decades, there has been increasing scientific investigations exploring lipid from algae, microbes, and insects as alternatives to traditional agro- and marine-based sources. This review, therefore, presents progress made in microbial and insect oils production, with emphasis on sustainability. Emerging extraction techniques, regulatory and safety requirements, and challenges that exist in the production and utilization of these new lipids are also discussed. The review shows that lipids from a wide range of oleaginous microorganisms and insect species have the potential to serve as a valuable ingredient for healthful food preparation. However, challenges such as cultural acceptance, lack of standardized regulations, high cost, and low yield associated with most emerging environmentally friendly extraction technologies continue to hinder widespread use or adoption of microbial and insect lipids on a global scale. These challenges call for innovations to reduce cost of production and improve lipids yield. So far, a substantial progress has been made in the utilization of readily available feedstocks such as industrial food wastes and sugar-rich industrial wastewater to grow insects and microorganisms which will significantly reduce the processing costs.

There is an unmet demand for plant-based ingredients with desirable nutritional, techno-functional properties, and health benefits. In this study, the composition, nutritional quality, and bioactives in industrial hempseed flours and protein isolate generated by milling, germination, isoelectric precipitation (IEP), and enzyme-assisted extraction (EAE) were evaluated. Moisture, ash, fat, protein, phytic acid, tannin, and trypsin inhibitor content of the hempseed flours and protein isolate were 2.80%–6.46%, 5.07%–28.89%, 0.00%–31.44%, 22.71%–89.94%, 0.55%–1.05%, 274.24–1300.76 μg/g, and 0.00–42.66 U/g, respectively. IEP resulted in the highest protein content (89.94%), indicative of its effective to isolate hempseed protein. Germination and IEP significantly reduced phytic acid and tannin contents by 1.53- and 3.63-fold, respectively. All processing methods improved in vitro protein digestibility (IVPD). SDS-PAGE analysis revealed comparable band patterns in milled and protein isolate, with a strong 50 kDa band attributed as edestin. Amino acid analysis showed that EAE augmented total essential amino acids, particularly protease. Milling and pronase treatment yielded the highest and lowest IVPD-corrected amino acid score (IVPDCAAS) of 76% and 47%, respectively. Milled and germinated flours contained varying amounts of γ-tocopherol, lutein, zeaxanthin, α-carotene, and β-carotene. Germinated flour exhibited elevated levels of total phenolic (14.36 mg/g), and flavonoid (1.76 mg/g) contents, FRAP, TEAC, and DPPH compared to the other flours suggesting superior antioxidant capacity. Strong positive correlations (r >0.70) were found between IVPD and phytic acid for the protein isolate, total phenolic content, and FRAP for IEP and germinated flours. Overall, hempseed flours with diverse properties could be produced using non-thermal processing.

The aim of this study was to use oleogels in compound chocolates. A control sample with cocoa butter (CNT) and two compound chocolates with hazelnut oil-sunflower wax oleogel (SWO-CC), and polyglycerol stearate oleogel (PGSO-CC) were prepared with the same recipe. The main properties and compositions of the samples were quite similar. While CNT sample included only 37.97% of total unsaturated fatty acids, it was 74.19 and 63.08% in the SWO-CC and PGSO-CC, respectively. The melting peak temperatures were 32.1, 25.4, and 23.8°C for CNT, SWO-CC and PGSO-CC. The samples had 11.75%, 74.25%, and 74.25% shape retention index values at 60°C. Clearly compound chocolates melted at lower temperatures, but retained their shape at higher temperatures. After 15-day temperature fluctuation storage, no fat bloom was developed. Rheological data showed that the PGSO-CC sample was stiffer among all, and the compound chocolates melted slowly up to 40°C, but CNT melted sharply at 38°C. Further, the PGSO-CC sample showed a lubricating behavior. Although CNT sample included 7 volatile aromatics, SWO-CC and PGSO-CC samples had 17 and 14 compounds, respectively. Trained panel described the samples with 13 attributes, and most profoundly the compound chocolates had lower shape, surface gloss, coffee, bitter, cooling, hardness scores, and higher coating scores. Consumer test revealed that compound chocolates had lower appearance scores, and equal aroma scores. The flavor score and acceptability were highest for the PGSO-CC sample. Overall, this study proved that heat stable and sensorially acceptable compound chocolates could be prepared from the oleogels.

In this paper, a colloidal dispersion at different pH containing soybean protein isolate (SPI) microgel particles and xanthan gum (XG) was used as the aqueous phase to prepare O/W emulsion gels with soybean oil. Properties of SPI microgel particles were analyzed by particle size, Zeta-potential, secondary structure, optical contact angle, dynamic interface tension, and SEM testing, respectively. Results showed that pH impact microgels particle size and Zeta-potential and their emulsification properties. It turned out that only at pH 3, 6, 7, and 8 can construct emulsions successfully. Based on a comparison of microstructure and macroscopic properties, it was found that at pH 3, proteins and polysaccharides were oppositely charged, electrostatic attraction between them reduced proteins located at the interface, and was more likely to form larger droplets, resulting in a bimodal droplet distribution and larger sizes. Conversely, at the pH of 6, 7, and 8, respectively, emulsions exhibited a uniform droplet distribution and more solid-like rheological properties due to the powerful electrostatic repulsion between SPI and XG. Also, emulsion gels co-stabilized with proteins and polysaccharides under electrostatic repulsion conditions showed an ideal recovery ability. Overall, this work would be beneficial to the use of emulsion gels in fat substitute systems.

Microscopic image analysis is a crucial tool in fat crystallization research, enabling the analysis of crystal size, network structure, fractal dimension and other parameters through binarization. It is essential to seek an appropriate thresholding algorithm to binarize fat crystal images, which plays a vital role in image segmentation. In this article, the effectiveness of 17 thresholding algorithms such as Default, Mean, IsoData, Otsu, Li and Triangle were analyzed in processing fat crystal images with different shapes, background colors and image intensities. This was expected to discover a stable and objective thresholding algorithm for the binarization of fat crystal images. The performance evaluation was conducted according to the peak signal noise ratio (PSNR), structural similarity index (SSIM) and region non-uniformity (RNU) parameter. Moreover, the comparative analysis of crystal size error, crystal area fraction and intraclass correlation coefficients (ICC) for fractal dimension values would provide a foundation for the selection of thresholding techniques for fat crystal network images. The results indicated that the Default algorithm exhibited remarkable robustness and applicability with high-quality and stable outputs in fat crystal image processing.