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• Extended food use of oats calls for knowledge on compositions and storage behavior. • Lipids, volatiles and tocopherols varied between 20 pure oat cultivar batches. • Nine-month storage of flour revealed differences in oxidative stability. • Minor correlations between lipids, tocols and volatile oxidation compounds detected. Recent data showing the compositional variation and storage behavior among different oat batches for the purpose of food remains limited. Lipids of twenty oat flour samples of pure cultivars grown in Finland during 2019 were extracted and fractionated into neutral and polar-rich lipids. Flour was stored for nine months, and profiles of volatiles and tocols were analyzed to reveal oxidative stability. The lipid content was 5.9–8.9 g per 100 g of flour [DW] and consisted of 78.7 ± 2.5 % neutral and 21.3 ± 2.5 % polar lipids. Palmitic (16 %), oleic (36 %), and linoleic (39 %) acids were the most abundant fatty acids. Neutral lipids had more oleic and less linoleic and palmitic acids than polar lipids. The fresh samples correlated with tocols, pentanal, 2-pentylfuran, 2-heptanone, nonanal, 2-butanone, and heptanal, while stored samples were associated with 3-octen-2-one, 2-octenal, hexanal, and octanal. Lipid composition and oxidative stability are essential factors for selecting oat batches for food applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The development of peanut oil volatile flavor requires oil to participate in thermal reaction. • Heating peanut oil to degrade the unsaturated fatty acids in the oil creates reducing aldehydes. • Linoleic acid is one of the precursors in the formation of the volatile flavor of peanut oil. • Develop a volatile flavor model capable of distinguishing different reactions. 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. [ABSTRACT FROM AUTHOR]

[Display omitted] • The evolution of volatiles in the lean and fat portions of bacon showed different patterns. • The aroma compounds were mainly provided by lean portion, and the optimal drying time was 24 h. • Eight key aroma compounds derived from different lipid fractions and fatty acids. • Linoleic acid was vital for the generation of key aroma compounds in non-smoked bacon. This study explored the evolution of key aroma compounds and their lipid precursors in the lean (LN) and fat (FT) portions of non-smoked bacon during hot air drying. The results showed that the LN portion contained most of the aroma compounds in the bacon (>88%). The volatile content of the FT portion increased as the drying time increased, whereas that of the LN portion reached a maximum within 24 h and then decreased. Based on the highest volatile contents (4889.48 ± 202.06 µg/kg) and sensory scores, 24 h was considered the optimal drying time. For key aroma compounds, hexanal and 2,3-octanedione were derived from free fatty acids and polar lipids. Notably, 1-octen-3-ol was generated only from polar lipids in the FT and LN portions. The 2-undecenal and (E, E)-2,4-decadienal were produced by the oxidation of neutral lipids in the FT portion. Dihydro-5-pentyl-2(3H)-furanone was derived from polar lipids in the LN portion. Altogether, these findings provide theoretical insights into improving the aroma of bacon by optimizing raw material selection and processing methods. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the relative reaction rate of protein and lipid oxidation in different biphasic model systems (linoleic acid; liposome; emulsion) containing myofibrillar protein (MFP at 1, 8 and 20 mg/mL) under hydroxyl radical stress. Protein oxidation markers exhibited significant changes in 2 h: reduced tryptophan fluorescence intensity, carbonyl formation, and extensive polymerization of myosin. In contrast, no detectable changes ( P  > .05) in lipid peroxide occurred within 2 h except for samples with 1 mg/mL MFP which showed an early TBARS formation. Of the three biphasic systems, the oxidative stability of lipids followed the order of emulsion > linoleic acid > liposome, indicating the steric role of proteins. In general, MFP was more susceptible to radicals than lipids, and a higher protein:lipid ratio was associated with a slower TBARS production and more rapid protein oxidation, suggesting a sacrificing role of MFP to protect lipids. [ABSTRACT FROM AUTHOR]

Highlights: [•] Roles of moisture on the lipid oxidation were tested in linoleic acid model system. [•] Deuterium was found in headspace volatiles formed from linoleic acid oxidation. [•] Moisture acted as a substrate for the formation of volatiles. [•] Moisture in oils plays an important role as a substrate for the lipid oxidation. [ABSTRACT FROM AUTHOR]

[Display omitted] • LA improved the absorption of 5-DMT by stimulating production of lipid droplets and chylomicron. • The amount of 5-DMT transported to the bacterial side also enhanced by oxidized LA. • Oxidized LA induced ROS, affected tight junction and caused damages to Caco-2 monolayer. Lipids usually contain a large ratio of polyunsaturated fatty acids (PUFAs), which are highly susceptible to oxidation. Presence of oxidized lipids in foods may affect the bioavailability of lipophilic bioactive components after ingestion. In this study, the effect of oxidized and unoxidized linoleic acid (LA) on the transport of a highly lipophilic bioactive citrus flavonoid (5-hydroxy – 6, 7, 8, 4′ tetramethoxylflavone or 5-DMT) was determined using a Caco-2 cell model. Results demonstrated that compared to free 5-DMT, unoxidized LA improved the trans-enterocyte absorption of 5-DMT by stimulating the production of lipid droplets and chylomicrons. Although the amount of 5-DMT transported across the enterocyte doubled by oxidized LA compared to free 5-DMT, it significantly induced reactive oxygen species (ROS), affected the function of tight junction and caused damages to the morphology of enterocyte monolayer. This study re-emphasized the importance of preventing lipid oxidation in foods. [ABSTRACT FROM AUTHOR]

Abstract: The bran collected at each of the five steps of milling yields (98–100%, 96–98%, 94–96%, 92–94% and 90–92%) was defatted. Defatted rice bran (DRB) was added to methyl linoleate (ML) under various conditions, and its suppressive effect on lipid oxidation was kinetically evaluated to investigate the effective use of surplus rice bran. The rate constant, k, empirically evaluated by the Weibull equation for the oxidation of ML with DRB, was lower than that without DRB and decreased with increasing the maximum milling yield of added DRB. The oxidation of ML strongly depended on the added amount of DRB, but the k value was almost constant for a specific amount of DBR added to ML. The dependency of the k value on relative humidity was weak, regardless of the addition of DRB. The difference between the k values for oxidation processes of ML, with and without DRB, increased with increasing temperature. [Copyright &y& Elsevier]

• A mixture of free fatty acids inhibited lipid oxidation in ground, turkey thigh. • Oleic acid and linoleic acid could convert hemoglobin to hemichrome in spectra. • Increased number of double bonds in FFA facilitated hemichrome formation. • ESR spectra indicates the heme-Fe was in a low-spin state after Hb reacted with FFA. • Hemichrome formation due to added FFA diminished the lipid oxidation capacity of Hb. The pro-oxidant and anti-oxidant effects of free fatty acids (FFA) in meat remain ambiguous. To clarify the role of FFA in lipid oxidation of muscle food, the FFA was added into two systems (turkey mince and washed turkey muscle (WTM)) and lipid oxidation was investigated. A mixture of FFA inhibited lipid oxidation in both systems. The absorbance spectrum of oxyHb and metHb was determined in the presence of C18:1 and C18:2. Conversion to hemichrome spectra was observed and was particularly rapid when metHb was mixed with C18:2. C18:2 was also reacted with metHb followed by a chromatography step to remove unbound C18:2, and termed 'modified Hb'. Electron spin resonance (ESR) spectra of the modified Hb was indicative of hemichrome formation. The modified Hb did not promote lipid oxidation in washed turkey muscle during storage. This suggested that hemichrome formation due to added FFA diminished the lipid oxidation capacity of Hb. [ABSTRACT FROM AUTHOR]