One-pot green synthesis of ZIF-8/IgG composite for the precise orientation and protection of antibody and its application in purification and detection of aflatoxins in peanut oil

This study presents a novel approach toward the one-pot green synthesis of ZIF-8/IgG composite, focusing on its precise orientation and protection of the anti-aflatoxins antibody. The antibody orientation is achieved through the specific binding of IgG to the Fc region of the antibody, while the antibody protection is accomplished by the structural change restriction of ZIF-8 framework to the antibody. Consequently, the antibody exhibits enhanced target capability and significantly improved tolerance to organic solvents. The ZIF-8/IgG/anti-AFT was employed for the purification and detection of AFTs by coupling with UPLC. Under optimized conditions, the recoveries of spiked AFTs in peanut oils are between 86.1% and 106.4%, with relative standard deviations (RSDs) ranging from 0.8% to 8.8%. The linearity range is 0.5-20.0 ng for AFB1 and AFG1, 0.125-5.0 ng for AFB2 and AFG2, the limit of detection is 0.1 ng for AFB1 and AFG1, 0.03 ng for AFB2 and AFG2.

Contribution of lipid to the formation of characteristic volatile flavor of peanut oil

Lipid is an important precursor for volatile flavor formation, but it is not clear how to study the reactions involved in forming key volatile flavor compounds in peanut oil. In this paper, we innovatively established a flavor research model to investigate the contribution of different chemical reactions to the aroma compounds of peanut oil. The results showed that lipid participation in thermal reactions is necessary for forming major aroma compounds in hot-pressed peanut oil. Compared to the Maillard reaction, the lipid oxidation-Maillard reaction produces more compounds with 46 volatile substances identified. During the heating process, six new key substances were formed and the level of unsaturated fatty acids decreased by 7.28%. Among them, linoleic acid may be an important precursor for the formation of aroma components of hot-pressed peanut oil. Our study could provide theoretical guidance for understanding the volatile flavor mechanism of peanut oil and improving volatile flavor.

Effect of starch and peanut oil on physicochemical and gel properties of myofibrillar protein: Amylose content and addition form

Starch and peanut oil (PO) were widely used to improve the gel properties of surimi, however, the impact mechanism of addition forms on the denaturation and aggregation behavior of myofibrillar protein (MP) is not clear. Therefore, the effect of starch, PO, starch/PO mixture, and starch-based emulsion on the physicochemical and gel properties of MP was investigated. The results showed that amylose could accelerate the aggregation of MP, while amylopectin was conducive to the improvement of gel properties. The addition of PO, starch/PO mixture, or starch-based emulsion increased the turbidity, solubility, sulfhydryl content of MP, and improved the gel strength, whiteness, and texture of MP gel. However, compared with starch/PO mixture group, the gel strength of MP with waxy, normal and high amylose corn starch-based emulsion increased by 22.68 %, 10.27 %, and 32.89 %, respectively. The MP containing emulsion had higher storage modulus than MP with starch/PO mixture under the same amylose content. CLSM results indicated that the oil droplets aggregated in PO or starch/PO mixture group, while emulsified oil droplets filled the protein gel network more homogeneously. Therefore, the addition of starch and PO in the form of emulsion could effectively play the filling role to improve the gel properties of MP.

Characterization of Key Aroma Compounds and Main Contributing Amino Acids in Hot-Pressed Oil Prepared from Various Peanut Varieties

The production of peanut oil in the industrial sector necessitates the utilization of diverse raw materials to generate consistent batches with stable flavor profiles, thereby leading to an increased focus on understanding the correlation between raw materials and flavor characteristics. In this study, sensory evaluations, headspace solid-phase micro-extraction gas chromatography mass spectrometry (HS-SPME-GC-MS), odor activity value (OAV) calculations, and correlation analysis were employed to investigate the flavors and main contributing amino acids of hot-pressed oils derived from different peanut varieties. The results confirmed that the levels of alcohols, aldehydes, and heterocyclic compounds in peanut oil varied among nine different peanut varieties under identical processing conditions. The OAVs of 25 key aroma compounds, such as methylthiol, 3-ethyl-2,5-dimethylpyrazine, and 2,3-glutarone, exceeded a value of 1. The sensory evaluations and flavor content analysis demonstrated that pyrazines significantly influenced the flavor profile of the peanut oil. The concentrations of 11 amino acids showed a strong correlation with the levels of pyrazines. Notably, phenylalanine, lysine, glutamic acid, arginine, and isoleucine demonstrated significant associations with both pyrazine and nut flavors. These findings will provide valuable insights for enhancing the sensory attributes of peanut oil and selecting optimal raw peanuts for its production.

Effects of Pretreatment on Stability of Peanut Oil Bodies and Functional Characteristics of Proteins Extracted by Aqueous Enzymatic Method

Effects of dry and wet grind on peanut oil and protein yield, oil bodies (OBs) stability, fatty acid composition, protein composition and functional characteristics were systematically analyzed. Results showed that peanut oil and protein yields reached highest at dry grind 90 s (92.56% and 83.05%, respectively), while peanut oil and protein yields were 94.58% and 85.36%, respectively, at wet grind 120 s. Peanut oil and protein yields by wet grind was 2.18% and 2.78% higher than that of dry grind, respectively. Surface protein concentration (Г) and absolute value of zeta potential of OBs extracted by wet grind (WOBs) were 11.53 mg/m 2 and 18.51 mV, respectively, which were higher than OBs extracted by dry grind (DOBs), indicating stability of WOBs was higher than DOBs. Relative contents of oleic acid and linoleic acid in peanut oil, essential and hydrophobic amino acids in protein extracted by wet grind were higher than dry grind. There was little difference in protein composition between wet and dry grind, but thermal denaturation degree of protein obtained by wet grind was lower than dry grind. Solubility, oil retention, emulsion stability, foaming and foam stability of protein obtained by wet grind were better than dry grind. Results from this study provided theoretical basis for grind pretreatment selection of aqueous enzymatic method.

Green process for the preparation of resveratrol-containing high oleic acid peanut oil

Resveratrol (Res), a polyphenol compound with strong biological activity, is widely used in medicinal and health products. In this study, an innovative resveratrol high oleic peanut oil (Res-HOPO) was prepared utilizing self-developed cold pressing equipment and high oleic peanuts. The peanut roots were pretreated with four different methods, including ultra-fine crushing, ultrasound-treating, microwave-treating, and a combination of microwave-ultrasound-treating peanut roots. Under optimized conditions (microwave power of 15 W, ultrasound time of 28 min, and ultrasound power of 400 W), the Res-HOPO prepared by pretreating with a combination of microwave-ultrasound had the most Res (91.12 mg/kg). Except for the pretreated whole peanut roots, pretreating with microwave (40.49 mg/kg), ultrasound (39.03 mg/kg), and ultra-fine crushing of peanut root powder (22.57 mg/kg) resulted in the high Res content. The Res-HOPO had a satisfactory yield (40%), oleic acid content (74.05% ∼ 75.85%), no trans fatty acids, great physicochemical properties, higher nutritional value (4-fold increase in squalene and almost 10-fold increase in campesterol), an extended oxidation induction time (1.39 ∼ 22 times), and no heavy metals, pesticides, or aflatoxins. The four green pretreatment methods used for the preparation of Res-HOPO in this study were effective, which provided an innovative approach for developing nutritious and healthy edible oil.

Synthesis of Rice Husk-Based MCM-41 for Removal of Aflatoxin B1 from Peanut Oil

Edible oils, especially peanut oil, usually contain aflatoxin B₁ (AFB₁) at extremely high concentrations. This study focused on the synthesis of rice husk-based mesoporous silica (MCM-41) for the removal of AFB₁ from peanut oil. MCM-41 was characterized by X-ray diffraction, N₂ physisorption, and transmission electron microscope. MCM-41 was shown to have ordered channels with high specific surface area (1246 m²/g), pore volume (1.75 cm³/g), and pore diameter (3.11 nm). Under the optimal concentration of 1.0 mg/mL of the adsorbent dose, the adsorption behavior of MCM-41, natural montmorillonite (MONT), and commercial activated carbon (CA) for AFB₁ were compared. The adsorption of AFB₁ in peanut oil onto the three adsorbents was slower compared to that of AFB₁ in an aqueous solution. In addition, the pseudo-second-order kinetic model better fit the adsorption kinetics of AFB_1, while the adsorption mechanism followed the Langmuir adsorption isotherm on the three adsorbents. The calculated maximum adsorbed amounts of AFB₁ on MONT, MCM-41, and CA were 199.41, 215.93, and 248.93 ng/mg, respectively. These results suggested that MCM-41 without modification could meet market demand and could be considered a good candidate for the removal of AFB₁ from peanut oil. This study provides insights that could prove to be of economic and practical value.

Headspace Solid-Phase Microextraction Analysis of Volatile Components in Peanut Oil

Peanut oil is favored by consumers due to its rich nutritional value and unique flavor. This study used headspace solid-phase microextraction (HS-SPME) combined with gas chromatography (GC) and gas chromatography–mass spectrometry (GC-MS) to examine the differences in the peanut oil aroma on the basis of variety, roasting temperatures, and pressing components. The results revealed that the optimal conditions for extracting peanut oil were achieved through the use of 50/30 μm DVB/CAR/PDMS fibers at 60 °C for 50 min. The primary compounds present in peanut oil were pyrazines. When peanuts were roasted, the temperature raised from 120 °C to 140 °C and the content of aldehydes in peanut oil increased; however, the content of aldehydes in No. 9 oil at 160 °C decreased. The components of peanut shell oil varied depending on the peanut variety. The most marked difference was observed in terms of the main compound at the two roasting temperatures. This compound was a pyrazine, and the content increased with the roasting temperature in hekei oils. When the roasting temperature was lower, No. 9 oil contained more fatty acid oxidation products such as hexanal, heptanal, and nonanal. When the roasting temperature increased, No. 9 oil contained more furfural and 5-methylfurfural. Heren oil was easier to oxidize and produced nonanal that possessed a fatty aroma.

Foodomics Revealed the Effects of Extract Methods on the Composition and Nutrition of Peanut Oil

Processing technology has a significant effect on the functional quality of vegetable oil, but the exact mechanism is not yet very well known so far. The purpose of this study was to investigate the effects of extract methods on the composition and nutrition of peanut oil. Peanut oil was prepared by cold pressing, hot pressing, and enzyme-assisted aqueous extraction, and their trace components were determined by liquid chromatography-mass spectrometry (LC-MS). Serum and liver samples from Sprague-Dawley (SD) rats fed with different extract oils were profiled by gas chromatography-mass spectrometry (GC-MS) and LC-MS. The component analysis showed that different process technologies cause differentiation of trace active ingredients. Metabolomics analysis revealed that a high-fat diet causes serum and hepatic metabolic disorders, which can be ameliorated by hot-pressed and hydroenzymatic peanut oil, including downregulation of partial amino acids, fatty acids, phospholipids, and carbohydrates in cold-pressed peanut oil as well as the upregulation of palmitic acid, uric acid, and pyrimidine in enzyme-assisted aqueous oils. Canonical correspondence analysis (CCA) uncovered strong associations between specific metabolic alterations and peanut oil trace components. The data obtained in this study offers a new insight on the roles of oil processing.

Regional Sub-Saharan Africa Total Diet Study in Benin, Cameroon, Mali and Nigeria Reveals the Presence of 164 Mycotoxins and Other Secondary Metabolites in Foods

In the framework of the first multi-centre Sub-Saharan Africa Total Diet Study (SSA-TDS), 2328 commonly consumed foods were purchased, prepared as consumed and pooled into 194 composite samples of cereals, tubers, legumes, vegetables, nuts and seeds, dairy, oils, beverages and miscellaneous. Those core foods were tested for mycotoxins and other fungal, bacterial and plant secondary metabolites by liquid chromatography, coupled with tandem mass spectrometry. The highest aflatoxin concentrations were quantified in peanuts, peanut oil and maize. The mean concentration of the sum of aflatoxins AFB1, AFB2, AFG1 and AFG2 (AFtot) in peanut samples (56.4 µg/kg) exceeded EU (4 µg/kg) and Codex (15 µg/kg) standards. The AFtot concentration (max: 246.0 µg/kg) was associated with seasonal and geographic patterns and comprised, on average, 80% AFB1, the most potent aflatoxin. Although ochratoxin A concentrations rarely exceeded existing Codex standards, it was detected in unregulated foods. One palm oil composite sample contained 98 different metabolites, including 35.4 µg/kg of ochratoxin A. In total, 164 different metabolites were detected, with unspecific metabolites like asperglaucide, cyclo(L-pro-L-val), cyclo (L-pro-L-tyr), flavoglaucin, emodin and tryptophol occurring in more than 50% of composite samples. Aflatoxin B1 (AFB1), fumonisin B1 (FB1), sterigmatocystin (STC), ochratoxin A (OTA), citrinin (CIT) and many other secondary fungal metabolites are frequent co-contaminants in staple foods, such as maize and sorghum. Populations from North Cameroon and from Benin may, therefore, suffer chronic and simultaneous exposure to AFB1, FB1, STC, OTA and CIT, which are prevalent in their diet.

The Effect of Microwave Pretreatment on Micronutrient Contents, Oxidative Stability and Flavor Quality of Peanut Oil

The purpose of the present study is to investigate the changes in extraction yield, physicochemical properties, micronutrients content, oxidative stability and flavor quality of cold pressed peanut oil extracted from microwave (MW) treated seeds (0, 1, 2, 3, 4, 5 min, 700 W). The acid value and peroxide value of extracted oil from MW-treated peanuts were slightly increased but far below the limit in the Codex standard. Compared with the untreated sample, a significant (p < 0.05) increase in extraction yield (by 33.75%), free phytosterols content (by 32.83%), free tocopherols content (by 51.36%) and induction period (by 168.93%) of oil extracted from 5 min MW-treated peanut were observed. MW pretreatment formed pyrazines which contribute to improving the nutty and roasty flavor of oil. In conclusion, MW pretreatment is a feasible method to improve the oil extraction yield and obtain the cold pressed peanut oil with longer shelf life and better flavor.

Dark chocolate with a high oleic peanut oil microcapsule content

BACKGROUND

In accordance with the market demand for healthier indulgent food products, the present study aimed to determine the viability of the industrial production of dark chocolate with microcapsules of high oleic peanut oil content. Microcapsules of high oleic peanut oil were added to a control formulation using variations of mixing time.

RESULTS

The chocolates presented a rheology characterized by a pseudoplastic behavior adjusted to the Casson model (r > 0.98) and calorimetric behavior indicating melting onset (21 °C), peak melting (32 °C) and melting end (41 °C); caramelization peak (183 °C); and carbonization peak (237 °C), being considered thermal stable. The mixing time and the amount of microcapsules added to the control chocolate did not significantly influence the flow limit (11.09 ± 1.73 Pa) or the physical characteristics of the chocolate: pH (6.74 ± 0.14), maximum particle size (0.019 ± 0.001 mm), water activity (0.358 ± 0.023) and brittleness (18.61 ± 3.74 N). However, the addition of microcapsules with a high oleic peanut oil content significantly increased the chocolate whiteness index, thixotropy and Casson's plastic viscosity, although it did not have a significant influence on the mixing time.

CONCLUSION

The products obtained have a desirable quality and physical properties, being suitable for industrial production. © 2018 Society of Chemical Industry.

Changes of Seed Weight, Fatty Acid Composition, and Oil and Protein Contents from Different Peanut FAD2 Genotypes at Different Seed Developmental and Maturation Stages

The level of oleic acid in peanut seed is one of the most important factors in determining seed quality and is controlled by two pairs of homeologous genes ( FAD2A and FAD2B). The genotypes of eight F₈ breeding lines were determined as AABB, aaBB, AAbb, and aabb by real-time polymerase chain reaction and sequencing. Fresh seeds were collected from five seed developmental stages and, after drying, were used for chemical analysis. Our results showed that (1) as seeds developed, seed weight, oil content, and oleic acid level significantly increased, whereas four other fatty acid levels decreased, but protein content and another four fatty acid levels did not significantly change, (2) FAD2A/ FAD2B significantly affected fatty acid profiles but not oil and protein contents, and (3) the data were consistent across 2 years. The variability of seed quality traits revealed here will be useful for peanut breeders, farmers, processers, and consumers.