Effect of roasting on the chemical components of peanut oil

Innovative insights into the roasting-driven transformation of volatile compounds and quality markers in flaxseed (Linum usitatissimum L.) oil

Roasting is essential for developing the characteristic aroma of flaxseed oil (FSO), yet its impact on oil quality remains underexplored. This study employed headspace-gas chromatography-mass spectrometry coupled with multivariate analysis to elucidate the dynamic changes in volatile compounds and quality characteristics of FSO subjected to varying roasting temperatures. Our findings revealed that seven key aroma compounds, identified through the variable importance in the projection scores of partial least square-discrimination analysis models and relative aroma activity value, served as molecular markers indicative of distinct roasting temperatures. These compounds included 2,5-dimethylpyrazine, 2-pentylfuran, (E)-2-pentenal, 2-ethyl-3,6-dimethylpyrazine, heptanal, octanal, and 2-hexenal. Notably, roasting at 200°C was found to enhance oil stability and antioxidant capacity, with phenolic compounds and Maillard reaction products playing synergistic roles in bolstering these qualities. Network analysis further uncovered significant correlations between these key aroma compounds and quality characteristics, offering novel perspectives for assessing FSO quality under diverse roasting conditions. This research not only enriched our understanding of the roasting process's impact on FSO but also provided valuable guidance for the optimization of industrial roasting practices. This study would provide important practical applications in aroma regulation and process optimization of flaxseed oil. .

Peanut oils from roasting operations: An overview of production technologies, flavor compounds, formation mechanisms, and affecting factors

Fragrant peanut oils (FPOs) are commonly defined as edible peanut oils having strong natural roasted peanut flavor without peculiar unpleasant odors and produced from peanut kernels through roasting/steaming and pressing operations, etc. The flavor of FPOs plays a crucial role in their acceptability and applications and their flavor profiles are an important factor in determining their overall quality. This paper presents a systematic literature review of recent advances and knowledge on FPOs, especially their flavors, in which it is focused on the evaluation of volatile compounds, the factors influencing the formation of flavor compounds, and formation mechanisms of those typical flavor compounds. More than 300 volatiles are found in FPOs, while some key aroma-active compounds and their potential formation pathways are examined. Factors that have big influences on flavor are discussed also, including the properties of raw materials, processing technologies, and storage conditions. Ultimately, the paper highlights the challenges facing, including the challenges in flavor analysis, the relationship between volatile compounds and sensory attributes, as well as the opening of the blackboxes of flavor formations during the processing steps, etc.

Effect of radio frequency roasting on the lipid profile of peanut oil and the mechanism of lipids transformation: Revealed by untargeted lipidomics approach

Radio frequency (RF) heating has been proved an alternative roasting method for peanuts, which could effectively degrade aflatoxins and possesses the advantages of greater heating efficiency and penetration depth. This study aimed to investigate the influences of RF roasting on the lipid profile of peanut oil under 150 °C target temperature with varied peanut moisture contents (8.29 % and 20 %) and holding times (0, 7.5, and 15 min), using ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS)-based lipidomics. In total, 2587 lipid species from 35 subclasses were identified. After roasting, the contents of sterol lipid (ST) and subclasses of glycerophospholipids (GPs) and glycoglycerolipids increased significantly, while fatty acid (FA), Oxidized (Ox-) FA, cholesterol (CE), and all subclasses of glycerolipids (GLs) decreased, and 1084 differential lipids were screened. The highest ST and lowest CE contents in peanut oil were achieved by medium roasting (7.5 min). The raise in moisture content of peanut simply affected a few GPs subclasses adversely. Compared with hot air (HA) roasting, RF decelerated lipid oxidation, showing higher levels of diacylglycerol, triacylglycerol and FA, with no additional negative impact and only 69 exclusive differential lipids. During RF roasting, hydrolysis and oxidation of fatty acyl chains into secondary oxides were the central behaviors of lipids transformation. This study could provide insights into the lipid changes and transformation mechanism of peanut oil by RF roasting processing.

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.

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.

Understanding the role of lipids in aroma formation of circulating non-fried roasted chicken using UHPLC-HRMS-based lipidomics and heat transfer analysis

The role of lipids in aroma formation of circulating non-fried roasted (CNR) chicken with different roasting times was studied using ultra-high performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS)-based lipidomics and heat transfer analysis. Thirteen odorants were confirmed as important aroma compounds of CNR chicken, including dimethyl trisulfide, 3,5-dimethyl-2-ethylpyrazine, nonanal, and 1-octen-3-ol. A comprehensive lipidomics analysis identified 1254 lipids in roasted chickens, classified into 23 distinct lipid categories that included 281 phosphatidylcholines (PC), 223 phosphatidylethanolamines (PE), and 202 triglycerides (TG). Using OPLS-DA analysis, the lipid PG (18:1_18:1) showed promise as a potential biomarker for distinguishing between chickens subjected to CNR treatments with varying roasting times. The lipids PC, PE, and their derivatives are likely to play a crucial role in the formation of aroma compounds. In addition, TGs that contributed to the retention of key odorants in roasted chicken included TG (16:0_16:0_18:1), TG (16:0_16:0_18:0), and TG (16:0_18:1_18:1). Findings further showed that lower water activity and specific heat capacity promoted the formation and retention of aroma compounds during the CNR process. This study contributed to a better understanding of the formation of aroma compounds through lipid oxidation in roasted chicken.

Influence of seed-roasting degree on quality attributes of sunflower oil

To facilitate the typical flavor of sunflower oil, seed roasting is widely applied. In this study, the effects of seed-roasting degree (160, 180, 200°C for 0-25 min) on the quality attributes of sunflower oil were assessed, particularly tocopherols, sterols, total phenolics, fatty acids, and triglycerides composition as essential compounds for the nutritional value of the sunflower oil. Roasting seeds at a high temperature can significantly raise oxidative stability by 1.5-1.8 times, the content of carotenoids by 2.0-5.5 times, chlorophyll by 7.5-17.0 times, as well as increase the browning index by 4.0-10.0 times and deepen the color of the sunflower oil. However, the fatty acid and triglyceride profiles of sunflower oils have little change under distinct seed-roasting degrees. Synthetically considering the various indicators measured in the current study. It is recommended that the seed roasts at 160-180°C for about 20 min to ameliorate the oxidative stability and quality. Practical Application: A well-defined roasting process is very important for the food industry to be able to produce sunflower oil with desirable nutrition, unique flavor produced by the Maillard reaction and chemical properties of sunflower oil, which changes during the roasting. Considering the flavor, peroxide values, oxidation stability, and other quality attributes of oil obtained from the roasted seed, we found that sunflower seed oil better quality is obtained when roasted at 160- -180°C for about 20 min (e.g., 160°C for 20-25 min or 180°C for 15-20 min).

A novel whole peanut butter refined by stirred media mill: The size, microstructure, rheology, nutrients, and flavor

A novel whole peanut butter (PB) was developed using an emerging technology called stirred media mill (SMM). The impact of SMM on the size, microstructure, rheology, nutrient, and flavor of PB was investigated. The SMM treatment significantly decreased the particle size of PB, damaged cell structure, and released the oil body from cells. The apparent viscosity of PB decreased with the grinding process. Visual inspection revealed that the colloidal stability of PB was improved. The fatty acid composition was not affected by the grinding process. However, the tocopherol contents of the extracted oil slightly increased. Electronic nose and GC-MS analysis indicated that SMM could alter the flavor of PB after grinding for 45 min. Overall, SMM was a potential process technology to manufacture stable nut butter with smooth texture and delightful flavor profile.

Effect of Extraction Methods on the Physicochemical Properties, Chemical Composition, and Antioxidant Activities of Samara Oil

Samara oil (Elaeagnus mollis Diels kernel oil) exhibits diverse healthy functions; however, the effect of extraction on its quality is still unclear. The present study was undertaken to evaluate the effect of extraction methods (solvent extraction: ethyl acetate, acetone, n-hexane, and petroleum ether; mechanical extraction: hot-pressing and cold-pressing) on the color, acid value, peroxide value, fatty acid composition, bioactive compounds, antioxidant activities, and oxidative stability index of samara oil obtained from Elaeagnus mollis Diels kernels. The results indicated that extraction methods affected the physicochemical properties, chemical composition, and antioxidant activities of samara oil except for fatty acid composition and γ-tocopherol. The highest values of bioactive compounds including polyphenols (140.27 mg gallic acid equivalent (GAE)/kg) and carotenoids (42.95 mg/kg) were found in samara oil extracted with acetone. The values of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays, as well as oxidative stability index (OSI), were the highest in this oil. Correlation analysis results demonstrated that DPPH, ABTS, and OSI of samara oil were positively correlated with polyphenols and carotenoids. After evaluation, acetone could be used to extract samara oil. The study provides new information on the samara oil process.

Widely targeted metabolomic approach reveals dynamic changes in non-volatile and volatile metabolites of peanuts during roasting

Roasting influences the color, flavor, and antioxidant activities of peanuts. However, the biochemical mechanisms that occur during roasting are not well known. In this study, the dynamic changes in non-volatile and volatile metabolites in raw, light, and dark roasted peanuts were investigated using ultra-performance liquid chromatography with a widely targeted metabolomic approach based on tandem mass spectrometry and gas chromatography-mass spectrometry. A total of 738 non-volatile metabolites (comprising 12 subclasses) and 71 volatile metabolites (comprising 14 subclasses) were identified in raw and roasted peanuts. Significantly different non-volatile and volatile metabolites were detected. Among them, amino acids, sugars, and lipids (lysophosphatidylethanolamines and oxidized fatty acids) were found to be highly linked to flavor formation. In addition, the enhanced color and antioxidant activities of peanuts were attributed to the Maillard reaction and sugar degradation. These results provide comprehensive insights into the quality improvements of peanuts during roasting.

Plant-Based Dairy Alternatives-A Future Direction to the Milky Way

One significant food group that is part of our daily diet is the dairy group, and both research and industry are actively involved to meet the increasing requirement for plant-based dairy alternatives (PBDAs). The production tendency of PBDAs is growing with a predictable rate of over 18.5% in 2023 from 7.4% at the moment. A multitude of sources can be used for development such as cereals, pseudocereals, legumes, nuts, and seeds to obtain food products such as vegetal milk, cheese, cream, yogurt, butter, and different sweets, such as ice cream, which have nearly similar nutritional profiles to those of animal-origin products. Increased interest in PBDAs is manifested in groups with special dietary needs (e.g., lactose intolerant individuals, pregnant women, newborns, and the elderly) or with pathologies such as metabolic syndromes, dermatological diseases, and arthritis. In spite of the vast range of production perspectives, certain industrial challenges arise during development, such as processing and preservation technologies. This paper aims at providing an overview of the currently available PBDAs based on recent studies selected from the electronic databases PubMed, Web of Science Core Collection, and Scopus. We found 148 publications regarding PBDAs in correlation with their nutritional and technological aspects, together with the implications in terms of health. Therefore, this review focuses on the relationship between plant-based alternatives for dairy products and the human diet, from the raw material to the final products, including the industrial processes and health-related concerns.

Antioxidant Properties of Protein-Rich Plant Foods in Gastrointestinal Digestion—Peanuts as Our Antioxidant Friend or Foe in Allergies

Thermally processed peanuts are ideal plant models for studying the relationship between allergenicity and antioxidant capacity of protein-rich foods, besides lipids, carbohydrates and phytochemicals. Peanut is highly praised in the human diet; however, it is rich in allergens (>75% of total proteins). One-third of peanut allergens belong to the products of genes responsible for the defence of plants against stress conditions. The proximate composition of major peanut macromolecules and polyphenols is reviewed, focusing on the identity and relative abundance of all peanut proteins derived from recent proteomic studies. The importance of thermal processing, gastrointestinal digestion (performed by INFOGEST protocol) and their influence on allergenicity and antioxidant properties of protein-rich plant food matrices is elaborated. Antioxidant properties of bioactive peptides from nuts were also considered. Moreover, there are no studies dealing simultaneously with the antioxidant and allergenic properties of protein- and polyphenol-rich foods, considering all the molecules that can significantly contribute to the antioxidant capacity during and after gastrointestinal digestion. In summary, proteins and carbohydrates are underappreciated sources of antioxidant power released during the gastrointestinal digestion of protein-rich plant foods, and it is crucial to decipher their antioxidant contribution in addition to polyphenols and vitamins before and after gastrointestinal digestion.

Characterization of New Egyptian Linseed Varieties and the Effects of Roasting on Their Pigments, Tocochromanols, Phytosterols, Omega-3 Fatty Acids, and Stability

The purpose of this study was to explore the effects of roasting linseeds on the pigment, lipid profile, bioactive components, and oxidative stability of the extracted oils. The linseed varieties Giza 11, Giza 12, Sakha 3, and Sakha 6 were roasted at 180 °C for 10 min, and the oils were extracted by cold pressing. The results showed that, after roasting, there was an increase in oil percentage and peroxide value, as well as small increases in p-anisidine and acid values. Roasting also caused an increase in chlorophyll content, while lutein and β-carotene tend to slightly decrease, except in the Giza 11 variety. The total phenolics content was markedly enhanced after roasting. Omega-3 fatty acids were not affected by the roasting process. The total amounts of tocochromanol were found to decrease in the Giza 12 and Sakha 6 varieties after roasting. Plastochromanol-8 increased in all varieties after roasting. The phytosterol composition was minimally affected by roasting. Roasting enhanced the stability of the extracted oils, increasing the induction period and decreasing EC50 values. These results may thus help to discriminate between the different linseed varieties and serve to recommend the use of roasting to enhance the oxidative stability of extracted oil.

Effect of Different Extraction Methods on Quality Characteristics of Rapeseed and Flaxseed Oils

This study reports the effect of roasted pretreatment combined with screw press, hydraulic press, and Soxhlet extraction methods on various quality indexes of rapeseed and flaxseed oils, including the oil yield, sensory indexes (color, smell, clarity, viscosity, and colligation score), physicochemical properties (acid value, peroxide value, saponification value, moisture and volatiles), major components (fatty acid composition and triglyceride composition), and minor components (volatile compounds, total phenols, and vitamin E contents). The results indicated that the oil yield, sensory indexes, physicochemical properties, fatty acid composition, volatile compounds, total phenol, and vitamin E contents in vegetable oils have been significantly affected by different extraction methods. The yields of rapeseed and flaxseed oils of Soxhlet extraction method were increased by 30.10%–73.90% and 6.30%–54.40%, respectively, compared with other treatment groups. In addition, roasted pretreatment significantly increased the yields of oils by 4.10%–25.00% and 6.70%–23.15%, respectively, compared with the untreated group. The contents of linolenic acid and vitamin E in rapeseed and flaxseed oils extracted from screw press method were higher. In particular, the linolenic acid content of cold-pressed rapeseed oil extracted by screw press increased by 1.50%–23.80% compared with other treatment groups. In addition, the contents of vitamin E in cold-pressed rapeseed oil and flaxseed oil obtained by screw press increased by 1.22%–78.91% and 3.00%–18.80%, respectively. The Soxhlet extraction could improve oil yield and total phenol content, but the quality of the oil was inferior due to high acid values (0.93–3.36 mg KOH/g) and peroxide values (0.70–5.23 meq O2/kg). Furthermore, the hydraulic press method could extract vegetable oils with excellent sensory scores. The roasted pretreatment gives the rapeseed and flaxseed oils a good smell. The major volatile compounds in rapeseed and flaxseed oils were aldehydes, acids, alcohols, heterocycles, and ketones. Different extraction methods and pretreatment had no significant effect on the compositions and contents of triglycerides. This study provides a basic understanding on the selection of appropriate oil extraction techniques for oil extraction at a large scale.

Characterization of a novel squalene-rich oil: Pachira macrocarpa seed oil

Pachira macrocarpa is a woody oil crop with high economic and ornamental value. Although P. macrocarpa seeds are rich in oil, little information has been reported about its characterization. In this study, the fatty acids, minor components (tocopherols, squalene, phytosterols, and total phenols), antioxidant activity, cytotoxicity, thermal, and rheological behavior of the P. macrocarpa seed oil (PSO) were investigated for the first time. The results showed that the seeds contained 43.34% lipid, which was mainly composed of palmitic acid (49.96%), linoleic acid (31.22%), and oleic acid (13.48%). The contents of tocopherols, squalene, phytosterols, and total phenols in PSO were 42.01 mg/100 g, 96.78 mg/100 g, 119.67 mg/100 g, and 3.79 mg GAE/100 g, respectively. PSO showed relatively strong DPPH radical scavenging capacity (93.47 µmol TE/100 g) and high melting point (20.8°C). In addition, the oil exhibited Newtonian flow behavior and was not toxic to normal L929 cells at concentrations of 500-8000 µg/ml. As a whole, PSO may be considered as a valuable source for new multipurpose products for industrial utilization. PRACTICAL APPLICATION: Pachira macrocarpa is a woody oil crop and its seeds are rich in oil. Our study has investigated the physicochemical properties and chemical composition of the P. macrocarpa seed oil (PSO). The present study revealed PSO had potential as an edible oil, and it may be considered as a valuable source for new multipurpose products for food industrial utilization.

Effects of roasting and deodorisation on 3-monochloropropane-1, 2-diol esters, 3, 4-benzopyrene and trans fatty acids in peanut oil

Hazardous substances are readily produced during roasting and deodorisation in the preparation of peanut oil. The aim of this work was to investigate the variation of 3-monochloropropane-1, 2-diol ester (3-MCPDE), 3, 4-benzopyrene (BaP) and trans fatty acid (TFA) contents in the roasting and deodorisation segments of peanut oil production process. Roasting temperatures and durations significantly affected the contaminants contents in peanut oil; they increased significantly at a roasting temperature >210°C and time >60 min. In the deodorisation segment, the BaP and TFA contents were over the standard limits at a deodorisation temperature >210°C and time >140 min. Analysis showed that 3-MCPDE was significantly correlated with the formation of C18:2T (r = 0.979) and there was a linear relationship between BaP and C18:1T (Y = 0.509 C18:1T). This information will provide guidance for the precise and appropriate processing of peanut oil.

Bioactive β-Carbolines Harman and Norharman in Sesame Seed Oils in China

The β-carbolines in our diet, mainly including harman and norharman, are a group of biologically active, naturally occurring plant-derived alkaloids. Fragrant sesame seed oil is one of the most popular flavor edible oils in China. Considering that sesame seeds are roasted at 200-240 °C during the processing of flavor sesame seed oils, it is meaningful to investigate the levels of β-carboline compounds in various sesame seed oils. In this work, the levels of β-carbolines (harman and norharman) in different types of sesame seed oils in China (e.g., pressed fragrant sesame oil, ground fragrant sesame oil) have been determined systematically. The results showed that the levels of total β-carbolines in pressed fragrant sesame oils (700.5~2423.2 μg/kg) were higher than that in ground fragrant sesame oils (660.4~1171.7 μg/kg). Roasting sesame seeds at high temperatures (200-240 °C) led to higher levels of β-carbolines (660~2400 μg/kg) in fragrant sesame seed oils. In addition, the loss of tryptophan might be attributed to the formation of β-carbolines in sesame seeds during the roasting process. In general, fragrant sesame seed oils (pressed fragrant sesame oils, ground fragrant sesame oils) contain higher levels of β-carbolines due to the formation of harman and norharman during the roasting sesame seed process.

Influence of dry air and infrared pre-treatments on oxidative stability, Maillard reaction products and other chemical properties of linseed (Linum usitatissimum L.) oil

In this study, the influence of dry air and infrared pre-treatments on linseed oil (LO) yield, chemical properties, colour, pigment content, total phenolic content (TPC), Maillard reaction products (MRPs), fatty acid composition (FAC), radical scavenging activity (RSA), and oxidative stability index (OSI) were investigated. An increase in dry air and infrared roasting temperature had increased the LO yield, pigment content, a* value, TPC, RSA, OSI, and browning index (BI) while lowered the L* and b* values of LO. Higher OSI (2.24 h), chlorophylls (2.29 mg/kg), carotenoids (3.87 mg/kg), TPC (63.67 mg GAE/100 g), RSA (62.53%), BI (0.330), and MRPs (2.10 mg/kg) were detected in LO by dry air roasting at 180°C for 10 min. Dry air and infrared roasting had slightly affected the FAC of LO. Both dry air and infrared pre-treatments had influenced the LO quality characteristics. However, dry air roasting of linseed at 180°C for 10 min proved more effective in improving oxidative stability, antioxidant activity and other quality characteristics of LO.

SUPPLEMENTARY INFORMATION

The online version of this article at 10.1007/s13197-021-05023-6.

Effect of oilseed roasting on the quality, flavor and safety of oil: A comprehensive review

Roasting is widely applied in oil processing and employs high temperatures (90-260 °C) to heat oilseeds evenly. Roasting improves the extraction yield of oil by the generation of pores in the oilseed cell walls, which facilitates the movement of oil from oilseed during subsequent extraction. It also affects the nutritional value and palatability of the prepared oil, which has attracted consumers' attention. An appropriate roasting process contributes to better extraction of bioactive compounds, particularly increasing the total polyphenol content in the oil. Correspondingly, extracted oil exhibits higher antioxidant capacity and oxidative stability after roasting the oilseeds due to better extraction of endogenous antioxidants and the generation of Maillard reaction products. Furthermore, roasting process is critical for the formation of aroma-active volatiles and the improvement of desired sensory characteristics, so it is indispensable for the production of fragrant oil. However, some harmful components are inevitably generated during roasting, including oxidation products, polycyclic aromatic hydrocarbons, and acrylamide. Monitoring and controlling the concentrations of harmful compounds in the oil during the roasting process is important. Therefore, this review updates how roasting affect the quality and safety of oils and provides useful insight into regulation of the roasting process based on bioactive compounds, sensory characteristics, and safety of oils. Further research is required to assess the nutritional value and safety of roasted oils in vivo and to develop a customized roasting process for various oilseeds to produce good-quality oils.

Effects of Boiling and Roasting Treatments on the Content of Total Phenolics and Flavonoids and the Antioxidant Activity of Peanut (Arachis hypogaea L.) Pod Shells

This study was conducted to investigate the effect of boiling and roasting treatments on the phenolic and flavonoid contents and antioxidant activity of pod shells of two Sudanese peanut cultivars, Sodari and Ghabiash. The samples were subjected to a boiling process (1:5 w/v; 20 g/100 mL) at 100 °C for 45 min and a roasting treatment at 180 °C for 30 min. Results revealed that both cultivars are rich in phenolic compounds with high antioxidant activity in their shell. The boiling and dry roasting treatments significantly (p < 0.05) enhanced the total phenolic content, total flavonoid content, and antioxidant activity of the peanut shell for both peanut cultivars. The shells of Ghabiash peanut cultivar exhibited higher bioactive properties than the shells of Sodari cultivar, in which these properties were highly improved by roasting and boiling treatments. In general, peanut shells can serve as an important underutilized by-product, particularly after roasting treatment, for potential applications in food formulations.

Lipidomics reveals the changes in lipid profile of flaxseed oil affected by roasting

Roasting before oil extraction improves the oxidative stability and odor of flaxseed oil; however, the effect of roasting on lipid profile is still unclear. Herein, the changes in lipid profile in flaxseed oil during roasting were investigated based on lipidomic approach. 238 lipids including fatty acid (45 species), phospholipid (37 species), triacylglycerol (125 species), and oxidized fatty acid (21 species) were determined in unroasted and roasted flaxseed oils. After roasting, unsaturated fatty acids including oleic, linoleic, and lenolenic acid decreased. Triacylglycerols such as TAG(18:3/18:3/18:3) and TAG(18:2/18:3/18:3) had the same change trends with unsaturated fatty acids. However, phosphatidylcholines, phosphatidylethanolamines, phosphatidylglycerols, phosphatidylinositols, lysophosphatidylcholines, lysophosphatidylethanolamines, and oxidized fatty acids firstly increased and then decreased during roasting. Cyclic phosphadic acids identified for the first time in flaxseed oils increased rapidly at high-temperature roasting. 23 lipids were determined as potential biomarkers to differentiate the light and dark roasted flaxseed oils. Our finding could provide useful information for flaxseed oil processing and lipidomics.

Inhibition of Aspergillus flavus growth and aflatoxins production on peanuts over α-Fe2O3 nanorods under sunlight irradiation

Peanut is an important resource of edible oil and digestible protein in daily life, which is rich in the nutriments and antioxidants such as vitamins, minerals and polyphenols. However, peanut is susceptible to the contamination of Aspergillus flavus (A. flavus), which can produce highly carcinogenic toxins that brings serious threats to human health and food safety. Exploring green and effective methods to control A. flavus is meaningful. Herein, a green and economical way to control A. flavus on peanuts was demonstrated. It was found that the growth of A. flavus hyphae and germination of its spores could be inhibited in the presence of α-Fe₂O₃ nanorods under sunlight irradiation according to the agar diffusion method, flat colony counting method and fluorescence-based live/dead test. The diameter of inhibition zone was 22.3 ± 0.2 mm and the inhibition rate of spores germination was about 60 ± 5%, when the concentration of α-Fe₂O₃ was 10 mg/mL for 7 h sunlight irradiation. Most important, α-Fe₂O₃ showed the photocatalytic inhibition of A. flavus on peanuts under sunlight irradiation with the inhibition rate of about 90 ± 5%, and the production of aflatoxin B₁ and aflatoxin B₂ were reduced by 90 ± 2% and 70 ± 3%, respectively. By comparing the fat contents, protein contents, acid value, peroxide value and antioxidative compositions of peanuts, it was found that there was no obvious effect on the quality of peanuts after inhibition treatment. The findings provide a green, safe and economical strategy to control A. flavus on peanuts, which may be as a promising way to be used in food and agro-food preservation.

Cold-set or hot-set emulsion gels consisted of a healthy oil blend to replace beef fat in heat-treated fermented sausages

The current work aimed to investigate the utilization of gelled emulsion (GE) systems stabilized either with cold or hot gelation consisted of peanut and linseed oils as fat replacers in fermented beef sausages. The reformulation provided a healthier lipid profile, that led to decreasing total lipid content, cholesterol, and SFAs (from 46.6% to 23.5%) meanwhile increasing both MUFAs (from 47.3% to 51.0%) and PUFAs (from 4.7% to 25.4%) as well as improving nutritional ratios (ω-6/ω-3, PUFA/SFA, IA, and IT). Cold-set GE caused less significant changes in instrumental color and protected PUFAs compared with hot-set GE, whereas hot-set GE provided advantages over cold-set GE in terms of microstructure, purge loss, and sensory scores. Replacement of beef fat fully by a hot-set GE system instead of using a fat-GE mixture was effective in reducing oxidation. The results demonstrated that utilization of different GE systems can be an effective strategy to contribute to the development of lipid-modified fermented meat products.