Journal of the American Oil Chemists Society最新文献

In order to improve pectin antioxidant properties and enlarge the field of its potential applications, ferulic acid grafted pectin conjugates (PE-g-FA) were prepared using laccase as the catalyst at 30°C in an aqueous medium. The structures of PE-g-FA were characterized using UV–vis, FTIR, and NMR (1H and 13C). In addition, the antioxidant activity of PE-g-FA was evaluated according to the DPPH and ABTS free radical scavenging ability. Olive oil in water emulsions, containing emulsifiers WPI and PE-g-FA, were assessed for their physical and oxidative stability through particle size, zeta-potential, peroxide value (POV), and 2-thiobarbituric acid reactive substance (TBARS) formation. The results indicated that the formation of covalent bonds between the pectin carboxymethyl groups and FA hydroxyl group. The determination of the total phenolic content showed that PE-g-FA contained seven times more polyphenols than native PE. DPPH and ABTS free radical scavenging rate of 0.5HMP-g-FA were increased by 56.83% and 18.90% compared with HMP, respectively. In addition, the emulsion stabilized by WPI and 0.5HMP-g-FA showed smallest and uniform average particle size (855.9 ± 51.13 nm) on the 1st day. Although its POV value was slightly higher than that of emulsion stabilized by WPI and HMP, it was much lower than that of control groups. Overall, these results have important implications for enzymatic modification of pectin to obtain high antioxidant products and their application in pectin-based emulsions.

Enzymatically modified cheeses (EMC) aim to achieve, in a shorter time frame, a composition and sensory characteristics akin to those of aged cheese. This study analyzed the lipid profile, composition, free fatty acid (FFA) content, and sensory attributes of EMC pastes with the objective of emulating the flavor profile of a red smear-ripened cheese (SR). Two different smear ripened cheeses were utilized as references: SR1, aged for 2–3 months, and SR2 aged for 10 months. Twelve formulations of EMC were prepared using a fatty medium moisture cheese corresponding to Mercosur's Danbo type cheese (MD) as sole base, with the addition of the two types of SR cheeses and enzymes including exopeptidase, endopeptidase, and lipase, with varying concentrations of the latter. The EMC formulations exhibited a different physicochemical composition compared to the SR cheeses, with higher moisture, ash content, lower fat, and protein content. The highest total FFA contents were found in formulations with SR2, followed by formulations with SR1. As the concentration of lipase increased in the formulations, a greater degree of lipolysis was observed. Sensory profile was not influenced by the concentration of lipase, but rather depended on the type of cheese used as the base. All EMC samples prepared with SR1 besides those prepared with SR2 as the base cheese and the highest concentration of lipase, exhibited sensory profiles more closely resembling that of lightly aged SR1. The enzymatic modification of cheeses proved to be a useful tool for generating sensory profiles similar to slightly aged SR cheese.

The oxidation processes of unsaturated fatty acid methyl esters (FAMEs) and vegetable oils with molecular oxygen, proceeding through a radical mechanism, lead to the formation of a wide range of compounds. The primary oxidation products, hydroperoxides, undergo further decomposition to form products with a lower molecular weight or participate in cross-linking reactions leading to the accumulation of products with a higher molecular weight than the raw material. A number of researches note an increase concentration of oligomeric products and esters during the oxidation of FAME. The study of literary sources made it possible to establish that the accumulation of these substances correlates with each other. The mechanisms of ester formation described in the literature suggest the direct participation of either acids or hydroperoxides in these reactions. The work examines the main ways of accumulation of heavy products and “new” esters during the oxidation of FAMEs.

Diversification of the applications of fats and oils has led to increasing demands on their properties. Interesterification reactions are used to alter the composition of the constituent triacylglycerols (commonly known as triglycerides) to introduce the desired properties and enhance their value. Enzymatic interesterification catalysts have garnered attention owing to their safety, efficiency, and natural origin. However, enzymes are sensitive to temperature, moisture, and pH conditions, posing risks of inactivation. Additionally, enzymatic catalysts have slower reaction rates than chemical catalysts. To suppress the hydrolysis side reaction, lipases with high activity in microaqueous systems should be selected. Industrial reaction systems that use non-immobilized, powdered lipases overcome these issues owing to their insolubility in fats and oils. Continuous reaction systems, in which fats and oils are passed through a lipase-packed reaction column, offer a high processing capacity per unit enzyme weight, because the oils interact with high concentrations of lipase. These advances have led to the commercialization of medium- and long-chain triacylglycerols and cocoa butter substitutes. Our technology using powdered lipases offers the solution to the challenges of handling non-immobilized ones. This innovative approach allows for the efficient isolation and recovery of the enzymes after the reaction, maximizing their performance. Enzymatic catalysis can reduce the energy consumption and CO₂ emissions of interesterification reactions and eliminate the need for chemical catalysts by avoiding water washing and wastewater treatment. These distinctive features make enzymatic interesterification reactions promising for the industrial preparation of higher-value oils and fats worldwide.

Medium chain triacylglycerols (MCTs) are used as a functional oil in various food and pharmaceutical formulations because of their numerous health benefits and physical properties. Enzymatic esterification of glycerol with caprylic (C8:0) and capric acids (C10:0) in a molar ratio of 1:3.5 [50% (C8:0) and 50% (C10:0)] was carried out for the solvent free synthesis of MCTs using 5% (w/w) 1,3 specific lipase, Lipozyme RM IM and non-specific lipase, Novozym 435 in the presence of molecular sieves (10%) and low pressure conditions (50 and 150 mbar) at 50°C. Novozym 435 was more effective in the esterification reaction under 50 mbar reduced pressure, achieving ~54.74% triacylglycerol formation in 6 h, compared to Lipozyme RMIM, which achieved ~31.25% under the same conditions. Further reactions with Novozym 435 for 24 h showed that the maximum formation of MCTs occurred at 20 h (86.46 ± 3%), after which the reaction reached equilibrium. When 50 mbar was used, the formation of triacylglycerols enhanced 13 times compared with the results obtained at atmospheric pressure condition. Chemical characterization of the final MCTs confirmed the formation of four triacylglycerol species (TAG (8:0/8:0/8:0), TAG (8:0/8:0/10:0), TAG (8:0/10:0/10:0), and TAG (10:0/10:0/10:0) with LC–MS and NMR analysis. The melting and crystallization points of the synthesized oil was found to be −3.47°C and −23.48°C, respectively. Our findings contribute to developing a green process for synthesizing MCTs using two different fatty acids. The final product can be used as a nutraceutical oil or as an ingredient to enhance the food's physical properties.

Sesame oil (SO) produced through roasting technology offers pleasant flavor, often named roasted sesame oil (RSO) in the market. During the RSO production process, roasting is an essential technology in determining the flavor of RSO, which directly influences the consumer acceptance. Therefore, the present work systematically offers current knowledge on flavors and related issues of RSO, which will focus on production technologies (i.e., roasting technology, extraction technology, subsequent processing technology), flavor characteristics and flavor compounds, formation pathways of major flavor compounds (i.e., Maillard reaction pathway, oil oxidation pathway, thermal degradation pathway), and effects of roasting on the nutrition and safety. In addition, the present work provides an outlook for the future development of RSO industry, including the establishment of a grading system for the evaluation of RSO flavors, high-value utilization of by-products from RSO processing, and how to improve production efficiency of RSO. This work could provide a better understanding of RSO roasting process and promising information for better production of aromatic, nutritious and safe RSO by controlling/innovating the roasting process.

Biodiesel is an important alternative renewable liquid fuel due to its eco-friendly, non-toxic, and lower emissions. In this work, glycerol esterification catalyzed by zinc glycerolate was employed as a pretreatment to prepare biodiesel from acidified palm oil. The effects of stirring rate, catalyst amount, glycerol to free fatty acids (FFAs) molar ratio, and reaction temperature on the conversion of FFAs and concentration of monoglycerides, diglycerides, and triglycerides were investigated and optimized. The results show that the conversion of FFAs could reach 99.16% under the optimized conditions. Moreover, the kinetics of glycerol esterification catalyzed by zinc glycerolate at 160–200°C was obtained. Additionally, a comprehensive evaluation of the new biodiesel production process was also conducted. As a result, higher biodiesel content in the crude biodiesel phase was obtained after transesterification and separation using this new process. Overall, the study contributes to the utilization of waste oils to produce renewable energy and to minimize the waste management problem.

The search for new, more sustainable, and ecologically safe sources of energy has encouraged studies involving the production of biofuels from non-petroleum origin. Among the options for new energy sources, biodiesel is an important substitute for polluting fuels, with several cleaner and greener oils being suggested, especially new plant resources. This field evolved significantly in the last decades, and new raw materials for biodiesel production are welcome for new advances. In this vein, a potential source for biodiesel production is explored here, that is, two distinct biodiesels produced from different parts of the Acrocomia aculeata fruits—pulp and kernel. Results showed that biodiesel from pulp had an induction period of 12.77 h, ~3× higher than biodiesel from kernel, 3.96 h; iodine values in biodiesel pulp were ~7.5× higher than the kernel, 82 and 11 g I₂/100 g, respectively. These results are due to the profile of different antioxidants in these biodiesels and unsaturations in the fatty acids carbon chains. The degradation behavior of these biodiesels was monitored by the acid value via the traditional titration method, attesting the blend oxidation until 48 h of thermal degradation. In parallel, UV–Vis absorbances and fluorescence compared pure biodiesels and its blends with β-carotene and α-tocopherol standards. The wavelength at 445 nm was efficient in monitoring the degradation of blends rich in β-carotene—B25, B50, B75, B100. Primary and secondary compounds produced in the oxidative process were monitored at 230 and 270 nm, respectively, showing the pulp biodiesel antioxidant effect on the kernel one. Additionally, from the fluorescence contour map, it was possible to analyze regions of excitation/emission capable of monitoring the degradation process of the blends, found 415 nm, similar to expected for kernel and pulp oils described in the literature. Thus, the study provides information about changes in the optical profiles of biodiesel naturally rich in tocopherol and carotenoid antioxidants, encouraging the development of analytical methods based on absorption and fluorescence spectroscopies for this important resource of vegetable oils.

Low-field nuclear magnetic resonance technique combined with chemometrics was employed to establish the quantitative models for rapidly monitoring the changes of indicators (hydroxyl value (OHV), epoxy value (EV), polymeric hydroxyl value (POHV, reflecting the degree of polyetherification)) during the ring opening of epoxidized soybean oils. Comprehensively considering the variations of peak retention times and peak areas of LF-NMR spectra, OHVs of vegetable oils-based polyols were divided into low OHV (LOHV, 1.7–91.9 mg KOH/g) group and high OHV (HOHV, 94.1–229.4 mg KOH/g) group. In both LOHV and HOHV groups, OHV presented good linearity with T_2w, S₂₃, and S_Total of relaxation property with correlation coefficient of >0.90. EV and POHV also presented good linearity with relaxation property in both LOHV and HOHV groups. In LOHV group, data segment 1–1000 ms was taken with Deresolve, no preprocessing, and Deresolve as preprocessing methods for OHV, EV, and POHV, respectively, and partial least square (PLS) as the modeling method for all the three indicators, where RMSEPs of OHV, EV, and POHV models were 4.282, 0.114, and 4.061, respectively. In HOHV group, data segment 1–1000 ms was taken with no preprocessing as the preprocessing method and PLS as the modeling method for all the three indicators, where RMSEPs of OHV, EV, and POHV models were 3.117, 0.088, and 4.964, respectively. The established method will benefit polyol industry to online adjust the production parameters according to the monitoring results and achieve high-quality of vegetable oils-based polyols.

The ability of a fat crystal network to entrap liquid oil is known as oil binding capacity (OBC) and is an imperative property in semi-solid fats for use in confectionary, bakery, and snack products. Understanding the factors that increase the OBC of fats is crucial for developing fat-based foods that are more resistant to unwanted oil migration. In this study, fully hydrogenated palm-kernel based (FHPKO) lipid matrices were crystallized under different processing conditions to generate samples with a wide range of physical properties and OBC. Three dilutions were created by combining FHPKO with soybean oil (SBO)—75% FHPKO (containing 25% SBO), 50% FHPKO (50% SBO), and 20% FHPKO (80% SBO) and were crystallized at 33, 30, and 22°C; respectively. All the samples were crystallized using fast (FCR; 4.6°C/min) and slow (SCR; 0.1°C/min) cooling rates, as well as with (w) and without (wo) high-intensity ultrasound (HIU; 20 kHz). These processing conditions resulted in four different sets of samples—FCR wo HIU, FCR w HIU, SCR wo HIU, SCR w HIU. Immediately after processing, the sample's hardness, solid fat content (SFC), viscoelasticity (G′, G″, δ), microstructure, melting behavior (Tpeak, enthalpy), and OBC using a centrifuge method (labeled OBC_c) were analyzed. Samples were then stored at 22 and 5°C for 48 h and the aforementioned properties were measured again as well as OBC using a filter paper method (labeled OBC_p). Results show that both OBC_c and OBC_p were positively correlated with the sample's SFC (r_s = 0.912, p < 0.001; r_s = 0.777, p < 0.001), storage moduli (G′) (r_s = 0.674, p < 0.001; r_s = 0.526, p = 0.017), hardness (r_s = 0.793, p < 0.001; r_s = 0.812, p < 0.001), enthalpy (r_s = 0.842, p < 0.001; r_s = 0.812, p < 0.001), and the number of crystals (r_s = 0.655, p < 0.001; r_s = 0.728, p < 0.001); respectively. While no correlation between OBC_p and the sample's peak melting temperature and microstructure was recorded, a negative association between the sample's peak melting temperature (r_s = −0.782, p < 0.001), phase angle (δ) (r_s = −0.801, p < 0.001), and crystal diameter (r_s = −0.470, p = 0.004) was documented for OBC_c. These results suggest oil binding capacity of palm-kernel based crystallized fats can be increased by formulating harder fats that are elastic, contain more crystals, and have higher SFC and enthalpy. Additionally, the FCR with HIU processing conditions was the most effective in increasing the OBC.