Oxidation Of Unsaturated Fatty Acids Research Articles

Unravelling the formation of characteristic aroma of traditional braised pork through untargeted and targeted flavoromics

Untargeted flavoromics and targeted quantitative analysis of key aroma compounds, and analysis of dynamic change of aroma precursors concentration were used to investigate the aroma evolution of traditional braised pork and the underlying mechanism. The results indicated that lipid oxidation dominated at early cooking stage (0th–45th min), resulting in an increased concentration of most aldehydes, alcohols, ketones, such as hexanal, heptanal, octanal, nonanal, (E)-2-octenal, benzaldehyde, 1-octen-3-ol, and 2,3-octanedione, accompanied with an enhanced unpleasant fatty odor. From 45th to 73rd min, the seasonings alleviated excessive oxidation of unsaturated fatty acids accompanied with decreased aldehydes. Moreover, the diffusion of glucose and amino acids from seasonings to lean meat promoted the consumption of endogenous ribose and amino acids in meat through Maillard reaction, and facilitated the formation of dimethyl trisulfide, dimethyl disulfide, methanethiol, and 2-furfural, which contributed to the meaty, sauce-like, and sweety aroma, thus formed the characteristic aroma of traditional braised pork.

Effects of phenolic acid grafted-chitosan hydrocolloids on the aldehyde contents from lipid oxidation in golden pompano (Trachinotus blochii) fillets during pan-frying

The effects of phenolic acid grafted-chitosan hydrocolloids (CS-g-GA/FA) on aldehyde contents from lipid oxidation in golden pompano fillets during pan-frying was investigated with an established high-performance liquid chromatography-mass spectrum method. Results indicated that pan-frying induced profound lipid oxidation and aldehydes generation with propanal, hexanal, nonanal, trans, trans-2,4-decadienal, and 4-hydroxy-2-nonenal as the abundant species. CS-g-FA and CS-g-GA effectively decreased their contents by 23.74–27.42 %, 61.69–67.42 %, 41.83–53.91 %, 29.91–48.79 %, and 61.57–65.39 % after 3 min. Most aldehyde contents decreased with the extension of pan-frying time due to the volatilization and reaction. In terms of substrate depletion, CS-g-phenolic acids effectively inhibited unsaturated fatty acids oxidation due to their decent antioxidant activity than CS. The significant lower retention rates of aldehydes in the CS-g-phenolic acids groups compared with control in chemical mode confirmed the carbonyl ammonia condensation. These results suggested that CS-g-phenolic acids serve as novel coating to reduce hazardous compounds during aquatic products thermal processing.

Harnessing L-Cysteine to enhance lyophilization tolerance in Lactiplantibacillus plantarum: Insights into cellular protection mechanisms

Enhancing the viability of lyophilized microbial strains by modulating their physiological metabolism is an important focus of microbiological research. Certain amino acids have been shown to influence the physiology of microbial strains; however, their effect on strain survival during lyophilization remains largely unexplored. In this study, we employed five different amino acids to investigate the potential correlation between amino acid supplementation and the viability of Lactiplantibacillus plantarum during lyophilization. We discovered that the addition of 0.05 g/L L-cysteine could significantly improve the post-lyophilization viability of all four L. plantarum strains after culture. Subsequently, the mechanisms underlying this enhancement were elucidated using L. plantarum LIP-1 as a type strain. The results showed that L. plantarum metabolised L-cysteine to produce glutathione, which in turn decreased the levels of reactive oxygen species, enhanced hydroxyl radical scavenging, inhibited the oxidation of unsaturated fatty acids, and maintained cell membrane fluidity. As a result, cell membrane damage was attenuated, ultimately improving the lyophilization resistance of L. plantarum.

γ-Lactones in Canadian high arctic aerosols: Tracers for the oxidation of unsaturated fatty acids and intramolecular esterification of γ-hydroxyacids during polar sunrise

In this study, we detected for the first time a series of γ-lactones (C7-C16) isolated from Canadian high arctic aerosols collected from late February to June as the sun rises from below the horizon to the maximum. γ-Lactones were identified and quantified by GC-MS utilizing the fragment ion (m/z 85) of [C4H5O2]+. Their molecular distributions showed the predominance of C9 species (on average, 25 pg/m3) followed by C10, C8, C11, C12, C16, C15, and C7. The odd-carbon numbered γ-lactones such as C9 and C11 are produced by the oxidation of oleic (Δ9C18:1) and eicosanoic (Δ9C20:1) acids, respectively, to monocarboxylic acids in the atmosphere, followed by the subsequent oxidation to positional isomers of hydroxy acids and intramolecular esterification of γ-hydroxy acids. Unsaturated fatty acids, plausible sources of the γ-lactones, can originate from marine phytoplankton and terrestrial vegetation via long-range atmospheric transport to the Arctic. Series of ω-oxoacids were also detected with the predominance of C9 species, supporting the photochemical oxidation of biogenic unsaturated fatty acids in the Arctic atmosphere after polar sunrise and/or during the long-range transport to the Arctic.

Disruption of Cell Membranes and Redox Homeostasis as an Antibacterial Mechanism of Dielectric Barrier Discharge Plasma against Fusarium oxysporum.

Direct barrier discharge (DBD) plasma is a potential antibacterial strategy for controlling Fusarium oxysporum (F. oxysporum) in the food industry. The aim of this study was to investigate the inhibitory effect and mechanism of action of DBD plasma on F. oxysporum. The result of the antibacterial effect curve shows that DBD plasma has a good inactivation effect on F. oxysporum. The DBD plasma treatment severely disrupted the cell membrane structure and resulted in the leakage of intracellular components. In addition, flow cytometry was used to observe intracellular reactive oxygen species (ROS) levels and mitochondrial membrane potential, and it was found that, after plasma treatment, intracellular ROS accumulation and mitochondrial damage were accompanied by a decrease in antioxidant enzyme activity. The results of free fatty acid metabolism indicate that the saturated fatty acid content increased and unsaturated fatty acid content decreased. Overall, the DBD plasma treatment led to the oxidation of unsaturated fatty acids, which altered the cell membrane fatty acid content, thereby inducing cell membrane damage. Meanwhile, DBD plasma-induced ROS penetrated the cell membrane and accumulated intracellularly, leading to the collapse of the antioxidant system and ultimately causing cell death. This study reveals the bactericidal effect and mechanism of the DBD treatment on F. oxysporum, which provides a possible strategy for the control of F. oxysporum.

Comparison of sea buckthorn fruit oil nanoemulsions stabilized by protein-polysaccharide conjugates prepared using β-glucan from various sources

To understand the influence of β-glucans structure on the emulsifying properties of protein-polysaccharide conjugates, sodium caseinate (NaCas) was utilized to form glycosylation conjugates with varying degrees of glycosylation (10.68–17.50%) using three β-glucans from bacteria, yeast, and oats. This process induced alterations in the secondary structure of protein. The nanoemulsions prepared with the glycosylated conjugates exhibited superior stability compared to those formulated solely with NaCas, particularly under conditions of drastic pH fluctuations and extended storage periods. The nanoemulsion prepared with the NaCas-Salecan conjugate demonstrated exceptional stability at pH 4 and 6, or storage for 20 days. Additionally, it significantly attenuated the oxidation of unsaturated fatty acids and exhibited the lowest levels of aggregation, flocculation, and free fatty acid release rate during in vitro digestion. This study suggested the potential of the NaCas-Salecan conjugates in enhancing the stability of nanoemulsions and facilitating the colorectal-targeted delivery of sea buckthorn fruit oil.

Prevention of the Quality Degradation of Antarctic Krill (Euphausia superba) Meal through Two-Stage Drying.

To achieve a krill meal of high quality, a two-stage drying involving hot-air drying and vacuum drying was investigated. Five experimental groups were established according to the different drying conditions in the second stage, including 95 °C and 101 kPa, 95 °C and 60 kPa, 75 °C and 101 kPa, 75 °C and 60 kPa, and 75 °C and 20 kPa. The results showed that reducing the drying temperature and vacuum pressure in the second stage had a significant impact on the drying characteristics, sensory quality, and bioactive compounds of krill meal. Among all five groups, the drying condition of 75 °C and 60 kPa maintained a high drying rate while preserving a phospholipid content of 30.01 mg/kg and an astaxanthin content of 37.41 mg/kg. It also effectively reduced the isomerization of astaxanthin and the oxidation of unsaturated fatty acids. These results suggested that the two-stage drying method may contribute to the production of high-quality krill meal.

The effect of sesamol on endogenous substances and oxidative stability of walnut oil.

This study explored the effect of sesamol on the stability of walnut oil based on the changes of endogenous characteristics in the oxidation process, which provided a theoretical reference for the application of natural antioxidants in walnut oil. A total of 300 mg/kg sesamol (SP), compound antioxidant AC (sesamol 353.62 mg/kg, citric acid 149.60 mg/kg, and BHA 76.33 mg/kg) and 35% sesame oil (35%-SO) were added to walnut oil respectively; in addition, 200 mg/kg t-butylhydroquinone (TBHQ), butylated hydroxyanisole (BHA), and citric acid were used as controls and blank walnut oil to study their effects on peroxide value, acid value, carbonyl compounds, conjugated olefins, phenols, flavonoids, sterols, vitamin E, β-carotene, and 51 fatty acids of walnut oil and their correlation between endogenous antioxidant components. The results showed that the addition of SP, 35%-SO, and AC could inhibit the increase of peroxide value, acid value, and carbonyl compounds in walnut oil, and could inhibit the decrease of β-carotene, total phenols, total sterols, and vitamin E. SP and 35%-SO could inhibit the decrease of total flavonoids, and several antioxidants could inhibit the decrease of endogenous antioxidant components in walnut oil. At the same time, it can better inhibit the change of unsaturated fatty acids in walnut oil. By the end of oxidation, the unsaturated fatty acids of blank walnut oil decreased by 10.31%, but AC, SP, and 35%-SO treatment groups increased by 10.90, 5.09 and 4.13%, respectively. Indicating that it had a certain protective effect on unsaturated fatty acids in walnut oil. There was a certain correlation between the endogenous substances of walnut oil. so the addition of several antioxidants can enhance the endogenous antioxidants of walnut oil, inhibit the oxidation of unsaturated fatty acids, and inhibit the increase of carbonyl compounds, codienes, acid value, and peroxide value. SP and AC have better antioxidant effects on walnut oil and improve the stability of walnut oil.

Effect of Cold Plasma‐Treated Turmeric on the Oxidative Stability and Quality of the Oil From the Milk Thistle Seeds

Many studies have been carried out on the antioxidant effects of medicinal plants in edible oils. One of those plants is turmeric, which, due to its biological and antioxidant compounds such as curcuminoids, has a strong antioxidant effect and prevents oxidation of unsaturated fatty acids (FAs). In this study, turmeric at different levels (5% and 10% w/w) was used to increase the oxidative stability of the milk thistle (Silybum marianum L.) seed oil (MTSO). Additionally, to improve the performance of turmeric, cold plasma (CP) treatment was used at different durations (5 and 10 min). The effect of turmeric on the quality parameters of MTSO was investigated during different storage times (1, 30, and 60 days). The results indicated that the addition of turmeric treated with CP significantly (p < 0.05) decreased the acidity value (AV) (1.00–0.62 mg NaOH/g oil) and the peroxide value (PV) (4.47–3.65 mEq O2/kg oil) and also increased the total phenolic content (1003.23–1116.90 mg/GAE/100 g oil), antioxidant activity, α‐tocopherol, and finally the oxidative stability compared to the control sample and oil containing untreated turmeric. Furthermore, gas chromatography (GC) analysis of the oil sample of the FA profile containing CP‐treated turmeric revealed the higher ratio of unsaturated FAs (i.e., linoleic and arachidonic acid) and lower saturated FA content (palmitic and stearic acid) compared to oil samples containing untreated turmeric. To conclude, CP treatment increased turmeric performance and improved the quality characteristics of MTSO.

Antioxidant Activity and Tyrosinase Inhibitor of Red Betel Leaf Extract

Red betel leaf (Piper Crocatum) contains flavonoids, tannins, steroids, and alkaloids, known to act as antioxidants. This study aimed to determine the antioxidant activity of red betel leaf extract. The solvents used for the extraction process are ethanol and n-hexane. The thiobarbituric acid (TBA) method was used to determine antioxidant activity. The results showed that the extract of 200 ppm inhibited fatty acid oxidation by 52.13%. No significant difference (α = 0.05) inhibition of unsaturated fatty acids oxidation between the sample and α-tocopherol at 200 ppm. The ethanol extract of red betel can inhibit the tyrosinase enzyme higher than the n-hexane extract of red betel, as seen from the IC50 value of the ethanol extract of red betel of 1655 ppm, while the IC50 value of n-hexane of red betel is 3090.56 ppm.

A Novel Strategy for the Demulsification of Peanut Oil Body by Caproic Acid.

The aqueous enzymatic method is a form of green oil extraction technology with limited industrial application, owing to the need for the demulsification of the oil body intermediate product. Existing demulsification methods have problems, including low demulsification rates and high costs, such that new methods are needed. The free fatty acids produced by lipid hydrolysis can affect the stability of peanut oil body (POB) at a certain concentration. After screening even-carbon fatty acids with carbon chain lengths below ten, caproic acid was selected for the demulsification of POB using response surface methodology and a Box-Behnken design. Under the optimal conditions (caproic acid concentration, 0.22%; solid-to-liquid ratio, 1:4.7 (w/v); time, 61 min; and temperature, 79 °C), a demulsification rate of 97.87% was achieved. Caproic acid not only adjusted the reaction system pH to cause the aggregation of the POB interfacial proteins, but also decreased the interfacial tension and viscoelasticity of the interfacial film with an increasing caproic acid concentration to realize POB demulsification. Compared to pressed oil and soxhlet-extracted oil, the acid value and peroxide value of the caproic acid demulsified oil were increased, while the unsaturated fatty acid content and oxidation induction time were decreased. However, the tocopherol and tocotrienol contents were higher than those of the soxhlet-extracted oil. This study provides a new method for the demulsification of POB.

Ferroptosis-Like Death in Microorganisms: A Novel Programmed Cell Death Following Lipid Peroxidation.

Ferroptosis is a new kind of programmed cell death of which occurrence in microorganisms is not clearly verified. The elevated level of reactive oxygen species (ROS) influences cellular metabolisms through highly reactive hydroxyl radical formation under the iron-dependent Fenton reaction. Iron contributes to ROS production and acts as a cofactor for lipoxygenase to catalyze poly unsaturated fatty acid (PUFA) oxidation, exerting oxidative damage in cells. While ferroptosis is known to take place only in mammalian cells, recent studies discovered the possible ferroptosis-like death in few specific microorganisms. Capacity of integrating PUFA into intracellular membrane phospholipid has been considered as a key factor in bacterial or fungal ferroptosis-like death. Vibrio species in bacteria and Saccharomyces cerevisiae in fungi exhibited certain characteristics. Therefore, this review focus on introducing the occurrence of ferroptosis-like death in microorganisms and investigating the mode of action underlying the cells based on contribution of lipid peroxidation and iron-dependent reaction.

Simultaneous Preparation of Chitin and Flavor Protein Hydrolysates from the By-Products of Shrimp Processing by One-Step Fermentation with Lactobacillus fermuntum.

One-step fermentation, inoculated with Lactobacillus fermentum (L. fermentum) in shrimp by-products, was carried out to obtain chitin and flavor protein hydrolysates at the same time. The fermentation conditions were optimized using response surface methodology, resulting in chitin with a demineralization rate of 89.48%, a deproteinization rate of 85.11%, and a chitin yield of 16.3%. The surface of chitin after fermentation was shown to be not dense, and there were a lot of pores. According to Fourier transform infrared spectroscopy and X-ray diffraction patterns, the fermented chitin belonged to α-chitin. More than 60 volatiles were identified from the fermentation broth after chitin extraction using gas chromatography-ion transfer spectrometry analysis. L. fermentum fermentation decreased the intensities of volatile compounds related to unsaturated fatty acid oxidation or amino acid deamination. By contrast, much more pleasant flavors related to fruity and roasted aroma were all enhanced in the fermentation broth. Our results suggest an efficient one-step fermentation technique to recover chitin and to increase aroma and flavor constituents from shrimp by-products.

Formation of free radicals in Chi-aroma Baijiu during aging process with fat pork

Soaking aged fat pork is a special aging process in the production of Chi-aroma Baijiu considered to involve the formation of free radicals. This study aimed to investigate the free radicals’ formation pathway in Chi-aroma Baijiu during aged fat pork soaking by using electron paramagnetic resonance (EPR) and spin trapping with 5,5-dimethyl-1-pyrrolin-n-oxide (DMPO). The alkyl radical adducts (DMPO-R) and hydroxyl radical adducts (DMPO-OH) were detected in Baijiu after soaking the fat pork for aging. During the preparation process of aged fat pork, alkoxy radicals adduct (DMPO-RO) were mainly detected since lipid oxidation. Oleic acid and linoleic acid, the two main unsaturated fatty acids in fat pork, produced alkoxy radicals in the oxidation process. The total amounts of spins in linoleic acid and oleic acid after 4-month oxidation treatment increased by 248.07 ± 26.65% and 34.17 ± 0.72% than 0-month. It indicated that the free radicals in aged Chi-aroma Baijiu were mainly derived from the two main unsaturated fatty acids in aged fat pork and linoleic acid had a stronger ability to produce free radicals than oleic acid. Alkoxy radicals (RO·) from fat pork reacted with ethanol in Baijiu to form alkyl radicals (R·). The peroxide bond of hydroperoxides from the oxidation of unsaturated fatty acid was cleaved to form hydroxyl radicals (·OH) that were transferred to Baijiu. The results provide theoretical guidance for the subsequent work of free radicals scavenging.

OXIDATIVE PROCESSES IN GRANULOSA CELLS OF COW OVARIAN FOLLICLES AT FOLLICULAR GROWTH

Article presents the research results on the respiratory activity and redox capacity of granulose layer cells of cow ovarian follicles under the physiological state of follicular growth. After the slaughter of the cows, the ovaries in physiological state of follicular growth were selected and the size of the follicles was evaluated. Cells of the granulosa layer were aspirated from small (< 4 mm), medium (4–7 mm) and large (> 7 mm) follicles and determined: intensity of oxygen absorption – polarographically, redox capacity – potentiometrically. K3[Fe(CN)6] was used as an extracellular electron acceptor. The share of oxygen consumed by aerobic glycolysis was determined by using sodium fluoride inhibitor, the NAD-dependent link of the mitochondrial electron transport chain - amytal, and the terminal (cytochrome oxidase) – sodium azide. The share of free-radical oxidation of unsaturated fatty acids in the realization of oxygen was detected by Na2EDTA.
 Granulosa cells from the ovary of follicular growth are characterized by respiratory activity and regenerative capacity, the intensity of which depends on the size of the follicles from which they are extracted. The highest values of the investigated indicators are characteristic of cells extracted from large follicles, lower – from small follicles, and the lowest values are from medium follicles. The high intensity of oxidative processes in granulosa from small follicles ensures the growth of oocytes, and from large follicles – maturation of the germ cell in the dominant follicle. At the same time, the increased intensity of oxygen consumption by the cells of small and dominant follicles is manifested against the background of limitations in electron acceptors in the extracellular environment.
 The use of inhibitors of ATP resynthesis of both glycolysis and individual links of the mitochondrial respiratory chain testify the activity of the indicated metabolic pathways in granulosa and the possibility of using alternative substrates to ensure the existence of cells. The main way of utilization of oxygen in the granulosa layer cells of small and large follicles is aerobic glycolysis, and from the medium there are alternative ways of supplying and using substrates. The largest flow of reducing equivalents into the extracellular space from the granulosa of a medium-sized follicle due to inhibition of glycolysis indicates that the source of the supply of reducing equivalents into the follicle cavity is glycolysis and this characterizes the dependence of the existence of cells on the indicated metabolic pathway.

The Impact of Fat Deterioration on Formation of Acrylamide in Fried Foods

AbstractThe current study investigates to what extent the reaction products of thermal degradation directly influence acrylamide formation in French fries. The frying tests at 170 and 180 °C are carried out with rapeseed oil for 32 h with 128 frying cycles. Acrylamide content in French fries is determined by LC‐MS/MS. Oxidative and thermal degradation is followed by measuring total polar compounds (TPC), di‐ and polymerized triacylglycerols (DPTG), monomer oxidized triacylglycerols (MONOX), p‐anisidine value (AnV), mono and di‐acyl‐glycerols (MAG and DAG), acid value (AV), epoxy fatty acids, iodine value (IV), saponification value, and fatty acid composition. During frying, the nature and degradation level of the frying medium have a direct impact on acrylamide formation. It can be shown that the pH‐dependent reaction is strongly inhibited at acid values above 0.5 mg KOH g−1 oil. Acidity measured as AV or FFA is mainly caused by oxidation, and less so by hydrolysis of triacylglycerols (TAG) as assumed up to now. Obviously, acid functional groups formed by oxidation of unsaturated fatty acids bound in TAG can act not only as catalyst for dimerization of TAG but also interact with asparagine as most important precursor for acrylamide formation so that no reaction with carbonyl groups for the formation of acrylamide is necessary.Practical applications: The same acidic functional groups that are known to catalyze the formation of dimeric TAG under frying conditions (160–190 °C, access of oxygen) in a nonradical mechanism apparently can also deactivate asparagine by protonization as a potential precursor for the formation of acrylamide. It is recommended not to reduce acidity of used frying oil by active filter aids below AV ≥ 0.5 as it helps to reduce acrylamide contamination of fried food.

Curcumin-loaded emulsions stabilized by the succinylated Antarctic krill proteins: Establishment of photodynamic inactivation to preserve salmon

The succinylated Antarctic krill proteins (SAKP) were fabricated using the ultrasound, and the curcumin-loaded emulsions stabilized by SAKP were selected as photosensitizers to construct a photodynamic inactivation (PDI) system to preserve salmon during storage at 4 °C. The SAKP treated with 200 W ultrasound (SAKP-U-200) presented an expanded and flexible structure, a decreased particle size from 465 nm to 358 nm, an increased surface hydrophobicity from 207.1 to 411.5, and its interface absorption capacity was increased by ∼8.0%, which displayed a superior encapsulation and emulsification ability compared with the other succinylated proteins. The emulsions stabilized by SAKP-U-200 efficiently loaded curcumin, and the established PDI mediated by the coating photosensitizers potently inactivated the bacteria in salmon by ∼3.0 Log10 CFU/g (99.9%) after the illumination of 18.72 J/cm2. Meanwhile, the PDI inhibited the changes of color and pH, maintained the integrity of muscle fibers, and reduced the water loss of salmon during the post-treatment storage. Notably, the PDI treatment inhibited the degradation of proteins by ∼7.7%, and decreased the oxidation of unsaturated fatty acids by ∼21%. Therefore, this study expands the application of PDI in preserving the storage quality of aquatic products.

Metabolomic analysis reveals the responses of docosahexaenoic-acid-producing Schizochytrium under hyposalinity conditions

The heterotrophic Schizochytrium sp. has been utilized to produce docosahexaenoic acids commercially in recent years. However, the high salinity required for Schizochytrium growth and docosahexaenoic acid production could result in salt-induced bioreactor corrosion and high downstream water treatment costs. Thus, exploring the physiological and metabolomic changes of Schizochytrium exposed to low-salt condition is beneficial for developing strategies of reducing the salt concentration during fermentation. In this study, Schizochytrium was exposed to 20, 10, 8, or 6 g/L of sea salt and the responses were determined. It was discovered that biomass accumulation was decreased, while starch and fatty acid was increased, especially unsaturated fatty acid accumulation in Schizochytrium, along with the salt concentration decrease. In addition, the metabolomic analysis showed that the intracellular pool sizes of NADPH, CoA, and ADP-GCS were significantly increased, while those of PEP and Ac-CoA were decreased, consistent with the content changes of fatty acid, starch, and biomass under hyposaline stress. The metabolomic analysis combined with further biochemical evidence revealed that fatty acid content elevation involved strengthening pentose phosphate pathway to provide more NADPH content; elevating CoA content to provide more precursors; upregulating inositol content, which was later demonstrated to enhance fatty acid accumulation; and activating the antioxidant system to reduce oxidation of unsaturated fatty acid caused by the reactive oxidative stress level. Finally, decreased content of glycerol, an important osmoregulator, along with enhanced cell wall polysaccharides, were also discovered in Schizochytrium as an adaptation to low-salt growth conditions. Our paper provides important guidelines for engineering Schizochytrium for low-salt cultivation in the future.

Interrogating Raisin Associated Unsaturated Fatty Acid Derived Volatile Compounds Using HS-SPME with GC-MS.

This study proposed to investigate the generation mechanism of raisins-derived volatile compounds during unsaturated fatty acids oxidation (UFAO) using a mixture of fatty acids (FAs) and four individual FA at different time intervals (0, 4, 8, 12, 16, and 20 days; 60 °C). During the sun-drying of 'Thompson Seedless' grapes (Vitis vinifera L.), a total of 39 UFAO-derived volatiles were characterized by the GC-MS. Firstly a pH value of 4.2 was optimized to proceed with a raisin drying-like UFAO model reaction. Afterward, GC-MS quantification revealed 45 UFAO-derived volatiles, and the maximum numbers of compounds were identified in the interaction of all FAs (39) following linoleic acid (29), erucic acid (27), oleic acid (25), and linolenic acid (27). Pentanoic acid, (E,E)-2,4-octadienal, and n-decanoic acid were only quantified in all FAs, linoleic acid, and erucic acid, respectively. This study showed that all FAs reactions were found to be responsible for the generation of a greater number of UFAO-derived volatiles with higher concentrations.

Effects of low‐pressure radio‐frequency cold plasma on the biochemical parameters and fatty acid profile of wheat flours

AbstractBackground and ObjectivesCold plasma (CP) treatment is a promising way to remove mycotoxins from cereal kernels, although its effects on nutrient contents remain unclear. This study evaluates the biochemical parameters, gelatinization properties, and fatty acid profile of Chinese hard‐white wheat flour treated with low‐pressure radio‐frequency (RF) CP (13.56 MHz, 140 Pa, helium or oxygen, 120 W, 0–180 s, 70 g sample).Findings120 W oxygen and helium plasma respectively required 90 and 120 s treatment to remove 50% deoxynivalenol (DON) from hard‐white wheat flour samples with 1.22 μg/g DON. A General Linear Model–Univariate analysis shows that oxygen and helium plasma both significantly increased water absorption rate, conductivity, and contents of reducing sugars, amylose, soluble protein, and saturated fatty acids in wheat flours but decreased the contents of soluble amino acids, total, unsaturated, mono‐unsaturated and poly‐unsaturated fatty acids, and enthalpy of gelatinization, and kept gelatinization peak temperature. At the same treatment time, helium plasma induced a higher water absorption rate, conductivity, and contents of pentosan and sulfhydryl groups in wheat flours than oxygen plasma. Oxygen plasma induced more reductions in mono‐ and poly‐unsaturated fatty acids in wheat flours than helium plasma. Compared with the untreated samples, helium plasma increased the values of water SRC, NaHCO3 SRC, and sucrose SRC, but decreased the lactic acid SRC, suggesting that the flour functional polymers were modified by helium plasma treatment, but oxygen plasma kept these four SRC values and did not significantly alter the functional polymers in wheat flour.ConclusionThe treatment with low‐pressure RF CP can increase hydrophilicity, and unsaturated fatty acid oxidation in wheat flours while kept starch gelatinization, and helium plasma can modify the flour's functional polymers.Significance and NoveltyThe suitable helium CP treatment (low‐pressure RF, 120 W, and 90–120 s) is a promising way to reduce the contaminants of wheat flours and improve their functional properties.