The underlying reasons for the efficient extraction of peanut oil by aqueous ethanol combined with roasting conditioning pretreatment.

To overcome the disadvantages of severe emulsification and difficulty in obtaining free oil during aqueous extraction of peanut oil, the effect of roasting assisted aqueous ethanol extraction on free oil recovery was investigated. When peanut kernels were roasted at 180 °C for 10 min, free oil recovery increased from 57% to 96%, and the acid and peroxide values of the peanut oil met the requirements of good quality. The degree of hydration swelling of proteins in the extract increased, and soluble solids were easier to aggregate, resulting in reduced emulsification and significantly higher free oil recovery. The roasting conditions selected were found to significantly promote protein hydrophilicity, aggregation and fusion of oil bodies, as well as cell rupture, which facilitated the release of free oil but with a lower degree of protein denaturation. This study may promote the practical application of aqueous extraction technology for peanut oil.

Activity and Characterization of Tocopherol Oxidase in Corn Germs and Its Relationship with Oil Color Reversion.

Color reversion has long been a major problem for the vegetable oil industry, and the enzymatic oxidation of γ-tocopherol is thought to trigger this phenomenon. In this study, first, the extraction, purification, and detailed characterization of tocopherol oxidase from fresh corn germs were performed. Then, the relationship between the enzyme reaction of γ-tocopherol and oil color reversion was verified. The results showed that the membrane-free extracts of raw corn germ performed specific catalysis of tocopherol in the presence of lecithin. In terms of the oxidation product, tocored (the precursor of color reversion) was detected in the mixture after the catalytic reactions, indicating that this anticipated enzyme reaction was probably correlated with the color reversion. Furthermore, the optimal pH and temperature for the tocopherol oxidase enzyme were 4.6 and 20 °C, respectively. In addition, ascorbic acid at 1.0 mM completely inhibited the enzymatic reaction.

Intrinsic properties and extrinsic factors of food matrix system affecting the effectiveness of essential oils in foods: a comprehensive review.

Essential oils (EOs) have been proved as natural food preservatives because of their effective and wide-spectrum antimicrobial activity. They have been extensively explored for potential applications in food industry, and substantial progresses have been achieved. However well EOs perform in antibacterial tests in vitro, it has generally been found that a higher level of EOs is needed to achieve the same effect in foods. Nevertheless, this unsimilar effect has not been clearly quantified and elaborated, as well as the underlying mechanisms. This review highlights the influence of intrinsic properties (e.g., oils and fats, carbohydrates, proteins, pH, physical structure, water, and salt) and extrinsic factors (e.g., temperature, bacteria characteristics, and packaging in vacuum/gas/air) of food matrix systems on EOs action. Controversy findings and possible mechanism hypotheses are also systematically discussed. Furthermore, the organoleptic aspects of EOs in foods and promising strategies to address this hurdle are reviewed. Finally, some considerations about the EOs safety are presented, as well as the future trends and research prospects of EOs applications in foods. The present review aims to fill the evidenced gap, providing a comprehensive overview about the influence of the intrinsic and extrinsic factors of food matrix systems to efficiently orientate EOs applications.

Both intrinsic properties and extrinsic factors of food matrix affect the EOs action.EOs influence on the food organoleptic aspects were reviewed.Promising strategies for overcoming the organoleptic aspects of EOs were listed.Future research prospects are outlined to accelerate EOs application in foods.

Physicochemical, Antioxidant and Anticancer Characteristics of Seed Oil from Three Chenopodium quinoa Genotypes.

Chenopodium quinoa Willd. is recognized to be an excellent nutrient with high nutritional content. However, few genotypes of quinoa were analyzed, so we found a knowledge gap in the comparison of quinoa seeds of different genotypes. This study aims to compare the physicochemical, antioxidant, and anticancer properties of seed oil from three C. quinoa genotypes. Seeds of three genotypes (white, red, and black) were extracted with hexane and compared in this study. The oil yields of these quinoa seeds were 5.68-6.19% which contained predominantly polyunsaturated fatty acids (82.78-85.52%). The total tocopherol content ranged from 117.29 to 156.67 mg/kg and mainly consisted of γ-tocopherol. Total phytosterols in the three oils ranged from 9.4 to 12.2 g/kg. Black quinoa seed oil had the highest phytosterols followed by red and white quinoas. The chemical profile of quinoa seed oils paralleled by their antioxidant and anticancer activities in vitro was positively correlated with the seed coat color. Black quinoa seed oil had the best antioxidant and anti-proliferation effect on HCT 116 cells by the induction of apoptosis in a dose-dependent manner, which may play more significant roles in the chemoprevention of cancer and other diseases related to oxidative stress as a source of functional foods.

Insights into an α-Glucosidase Inhibitory Profile of 4,4-Dimethylsterols by Multispectral Techniques and Molecular Docking.

Inhibition of α-glucosidase activity is closely related to the treatment of type 2 diabetes. However, the potential mechanism by which 4,4-dimethylsterols inhibit α-glucosidase has not been elucidated. In this work, the inhibitory activity and mechanism of 4,4-dimethylsterols against α-glucosidase were studied through kinetic analysis, fluorescence spectroscopy, ultraviolet spectroscopy, circular dichroism, and molecular docking. 4,4-Dimethylsterols showed higher inhibition activity against α-glucosidase than acarbose with an IC50 value of 0.71 mg/mL and a noncompetitive inhibition type. They could bind to α-glucosidase through van der Waals forces and hydrogen bonds and quench its endofluorescence with a static quenching mechanism. Changes in the secondary structure of α-glucosidase were induced by its binding interaction with 4,4-dimethylsterols. Molecular docking further indicated that a hydrogen bond was generated between OH at the C-3 position of 4,4-dimethylsterols and the α-glucosidase residue Arg-442. This study provides new insights into the potential utilization of 4,4-dimethylsterols as antidiabetic phytochemicals in dietary supplements.

Highly efficient synthesis of 4,4-dimethylsterol oleates using acyl chloride method through esterification.

In this study, the 4,4-dimethylsterol oleates were efficiently synthesized through esterification of 4,4-dimethylsterols and oleoyl chloride. The impact of reaction parameters on the 4,4-dimethylsterol conversion were investigated. The 4,4-dimethylsterol conversion increased with pyridine dosage, molar ratio of oleoyl chloride to 4,4-dimethylsterols, and temperature. The highest conversion of 99.27% was obtained with molar ratio of 1.1:1 at 313 K for 60 min. A second-order kinetic model describing acyl chloride esterification featuring high correlation coefficients was established. Arrhenius-Van't Hoff plot suggested activation energy and pre-exponential factor were 15.54 kJ mol-1 and 1.78 × 103 L mol-1 min-1, respectively. The molecular structure of 4,4-dimethylsterol oleates were finally identified by attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR), ultra-performance liquid chromatography system coupled with quadrupole time of flight mass spectrometry (UPLC-Q-TOF-MS), and nuclear magnetic resonance (NMR).

Activated complex theory is a classical theory suitable for food science with appropriate use.

Activated complex theory (ACT), apart from Van 't Hoff equation, has long been applying as an alternative tool to connect the kinetics (reaction rate constant, k) and thermodynamics parameters (including standard enthalpy of activation, △H++; standard entropy of activation, △S++; standard Gibbs free energy of activation, △G++). The study mainly focuses on ACT application in food systems, especially oil and fruit juice processing. Considering there are several improper calculations or mistakes often found in papers published recently in 2014-2019, three considerations are presented when applying the ACT, including 1) Understand that the reaction should be a single chemical elementary step; 2) Ensure that the units used should be consistent; 3) Effectively analyze the kinetics and thermodynamic parameters by choosing proper temperatures. This study is expected to further improve the understanding and correct application of this well-known theory in future work.

Gamma tocopherol, its dimmers, and quinones: Past and future trends.

Gamma-tocopherol (γ-T), the major form of vitamin E in many plant seeds and products derived from them, has been attracting increasing attention because of its health-promoting roles. However, the underlying molecular mechanisms are still unclear, to some degree. Furthermore, its dimmers and quinones are expected to be potential nutritious and pharmaceutical agents, however, the knowledge about these dimmers (γ-TBD and γ-TED) and quinones (para- and ortho-quinones) is relatively limited. Thus, a comprehensive summary of the history, chemical structure, source, determination, absorption, transport, and metabolism of its dimmers and quinones compared to γ-T has been reviewed. In addition, the antioxidant activity (AOA) and non-AOA activity of these substances are highlighted. It is suggested that more special attention be paid to the dimmers and quinones for better understanding and further applications.

Effects of chemical refinement on the quality of coconut oil.

Refinement is usually used to remove undesired components to improve coconut oil quality. In the present study, crude coconut oil (CCO) was refined in four stages: conventional degumming, neutralization, bleaching, and deodorization. Physiochemical indices during the refinement were evaluated: peroxide value (PV), free fatty acid (FFA), fatty acid composition; fat composition; triacylglycerol profile, micronutrient (e.g., tocopherols and sterols) and contaminant (e.g., 3-monochloropropane-1,2-diol esters (3-MCPD esters), and glycidyl esters (GEs) levels. Compared to CCO, the quality of refined oil was improved by reducing PV and FFA levels. No significant changes in triacylglycerol compositions were found during refinement. However, unsaturated fatty acids like oleic and linoleic acids were decreased after refinement. Also, some micronutrients like tocopherol and sterol were decreased from 12.39 to 0.10 mg/kg and from 679.69 to 426.50 mg/kg, respectively. The undesired contaminants, i.e., 3-MCPD esters and GEs, increased markedly during refinement.

Spray-dried novel structured lipids enriched with medium-and long-chain triacylglycerols encapsulated with different wall materials: Characterization and stability.

Novel structured lipids (SLs) enriched with medium-and long-chain triacylglycerols (MLCTs) were synthesized to combine the benefits of both arachidonic acid and medium-chain fatty acids; however, they are susceptible to oxidative degradation. In this work, the influences of the partial replacement of whey protein isolate (WPI) as the primary wall material by prebiotic carbohydrates, such as maltodextrin (MD) and inulin (IN) as the secondary wall materials on the physicochemical characteristics and oxidative stability of the spray-dried MLCTs-rich SLs microcapsules were investigated. The highest values of viscosity and zeta-potential were achieved by the WPI/IN (1:1) emulsions. Size distributions of all the emulsions were mono modal and became bimodal after microencapsulation process. The microcapsules prepared with WPI/IN (1:1) had the lowest lightness and the highest yellowness values. The partial replacement treatments increased the solubility and reduced the moisture content of the produced microcapsules. The partial replacement of WPI by IN significantly enhanced the encapsulation efficiency (89.10 ±â€¯1.03%), wettability properties (205 ±â€¯10.61 S), and decreased the incidence of surface oil on the microcapsules. The free oil content was noted as 5.73 ±â€¯0.05, 3.83 ±â€¯0.01, and 2.40 ±â€¯0.03% for the microcapsules produced using WPI, WPI/MD (1:1), and WPI/IN (1:1), respectively. Larger microcapsules and fairer flowing properties were achieved in the powders produced with only WPI. The partial replacement of WPI by IN provided the best oxidative stability of the microencapsulated MLCTs-rich SLs. The results revealed that MD and IN with WPI together, particularly IN proved to be a good substitute secondary wall material for spray-dried MLCTs-rich SLs, therefore suggesting its usefulness in functional food applications.

Phytochemical and Biological Characteristics of Mexican Chia Seed Oil.

The purpose of this research was to investigate the chemical profile, nutritional quality, antioxidant and hypolipidemic effects of Mexican chia seed oil (CSO) in vitro. Chemical characterization of CSO indicated the content of α-linolenic acid (63.64% of total fatty acids) to be the highest, followed by linoleic acid (19.84%), and saturated fatty acid (less than 11%). Trilinolenin content (53.44% of total triacylglycerols (TAGs)) was found to be the highest among seven TAGs in CSO. The antioxidant capacity of CSO, evaluated with ABTS•+ and DPPH• methods, showed mild antioxidant capacity when compared with Tocopherol and Catechin. In addition, CSO was found to lower triglyceride (TG) and low-density lipoprotein-cholesterol (LDL-C) levels by 25.8% and 72.9%respectively in a HepG2 lipid accumulation model. As CSO exhibits these chemical and biological characteristics, it is a potential resource of essential fatty acids for human use.

Effects of heat pretreatment of wet-milled corn germ on the physicochemical properties of oil.

Corn germ oil is removed from the milled germ using a conditioning (heating) process, followed by mechanical expelling and/or hexane extraction. In this study, the effect of pretreatment by oven roasting (OR) and microwave (MW) radiation on wet-milled corn germ was investigated. Three OR temperatures (125, 150, and 175 °C) were used with 60 min exposure, and MW pretreatments were established by combining two powers (440 and 800 W) and three pretreatment times (4, 6, and 8 min). The levels of red value, 1,3-diacylglycerol, total diacylglycerol, free fatty acid, and oleic acid increased substantially, while those of triacylglycerol (TAG), linoleic, and linolenic acid decreased significantly following OR. There were no significant differences in TAG compositions following OR and MW treatments. Both heat pretreatments significantly increased the total tocopherol content. δ-Tocopherol showed minimal changes, while ß-tocopherol progressively increased after the heat treatments. No significant differences in phytosterols levels were observed among most samples. The MW radiation Proper roasting temperatures or MW radiation times could enrich the content of individual tocopherols and phytosterols, and improve the oxidative stability of oil. The MW radiation tends to be more applicable and sustainable for oil industry to improve the quality of corn germ oil.

Production of sn-1,3-distearoyl-2-oleoyl-glycerol-rich fats from mango kernel fat by selective fractionation using 2-methylpentane based isohexane.

High-purity isohexane containing 88.12% 2-methylpentane, which has a higher polarity than industrial hexane, was selected to selectively fractionate mango kernel fat to produce 1,3-distearoyl-2-oleoyl-glycerol (SOS)-rich fat. The three-stage fractionation process was optimized by considering the stearin yield and its SOS content to obtain a third stearin (TS). This fat contained a high percentage of SOS (69.2%) with only 0.8% diacylglycerol. Mass spectra and sn-2 fatty acid analyses further revealed that the TS was mainly composed of symmetrical monounsaturated triacylglycerols. Compared with cocoa butter (CB), the unique composition of the TS improved its thermal properties (35.6% and 0% solid fat content at 35°C for the TS and CB, respectively). In particular, tempered binary fat blends, which were composed of 20-50% TS and 50-80% CB, showed acceptable compatibility at 20-28°C. The TS could be utilized by chocolate manufacturers to make products suitable for sale and consumption in tropical conditions.

Synthesis of 1,3-distearoyl-2-oleoylglycerol by enzymatic acidolysis in a solvent-free system.

1,3-Distearoyl-2-oleoylglycerol (SOS) is widely used as a cocoa butter improver and an anti-blooming agent in the chocolate industry. In this study, an effective process was developed to prepare SOS by enzymatic acidolysis. Under optimal reaction conditions (substrate molar ratio of 12, NS40086 loading of 10%, a solvent-free system, 75°C for 4h), a SOS yield of 70.2% was obtained. Subsequently, two-step purification was applied to purify the crude SOS product. Free fatty acids were completely removed after molecular distillation. After acetone fractionation, the purity of SOS reached 92.2% with an 85.1% recovery. Comparison of various physicochemical properties of purified SOS and a commercial cocoa butter improver showed their properties to be similar. This study provides an effective and sustainable process for the synthesis of SOS product, which is expected to be used as a high-quality cocoa butter improver or an anti-blooming agent in the chocolate industry.