Lipid and volatile profiles of Finnish oat batches of pure cultivars: Effect of storage on the volatile formation.

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.

Quality of Protein Isolates and Hydrolysates from Baltic Herring (Clupea harengus membras) and Roach (Rutilus rutilus) Produced by pH-Shift Processes and Enzymatic Hydrolysis.

Fractionation is a potential way to valorize under-utilized fishes, but the quality of the resulting fractions is crucial in terms of their applicability. The aim of this work was to study the quality of protein isolates and hydrolysates extracted from roach (Rutilus rutilus) and Baltic herring (Clupea harengus membras) using either pH shift or enzymatic hydrolysis. The amino acid composition of protein isolates and hydrolysates mostly complied with the nutritional requirements for adults, but protein isolates produced using pH shift showed higher essential to non-essential amino acid ratios compared with enzymatically produced hydrolysates, 0.84-0.85 vs. 0.65-0.70, respectively. Enzymatically produced protein hydrolysates had a lower total lipid content, lower proportion of phospholipids, and exhibited lower degrees of protein and lipid oxidation compared with pH-shift-produced isolates. These findings suggest enzymatic hydrolysis to be more promising from a lipid oxidation perspective while the pH-shift method ranked higher from a nutrient perspective. However, due to the different applications of protein isolates and hydrolysates produced using pH shift or enzymatic hydrolysis, respectively, the further optimization of both studied methods is recommended.

Predicting the Properties of Industrially Produced Oat Flours by the Characteristics of Native Oat Grains or Non-Heat-Treated Groats.

The aim of this study was to determine whether the properties of the native oat grain or non-heat-treated groats (laboratory-scale dehulling) can be used to predict the quality of the industrially produced oat flour produced from heat-treated groats. Quality properties such as the color, hectoliter weight, thousand seed weight and hull content of Finnish native grains (n = 30) were determined. Furthermore, the relationship between the properties of the native grains and the chemical composition of the raw oat materials before and after the milling process were studied. A significant relationship (p < 0.01) was observed between the thousand seed weight of the native oat groats and the chemical composition of the industrially produced oat flour. Furthermore, the protein content of the native grains measured by NIT correlated with the chemical composition of the oat flours. These results suggest that the properties of oat flour produced on an industrial scale, including heat treatment, could be predicted based on the properties of native oat grains.

Evaluation of the composition and oxidative status of omega-3 fatty acid supplements on the Finnish market using NMR and SPME-GC-MS in comparison with conventional methods.

Previous studies disagree on the oxidative status of omega-3 supplements. The great deviation raises concerns about quality and the methods used to monitor it. This study investigated 49 omega-3 products for their fatty acid content, lipid class and oxidative status using official methods, gas and liquid chromatography with mass spectrometry and nuclear magnetic resonance spectroscopy. With minor deviations, omega-3 fatty acid content and lipid class of all products were as declared. 24% of studied products exceeded thresholds set by The Global Organization for EPA and DHA Omega-3s for peroxide and/or p-anisidine value suggesting a compromised oxidative status. However, peroxide and/or p-anisidine value were only suitable for detection of lipid oxidation in 90% or 73%, respectively, of the products. Analysis of volatile oxidation compounds can be an alternative method for p-anisidine value. Nuclear magnetic resonance spectroscopy was shown to be a rapid method for determination of oil type and lipid class.

Sephadex LH-20 fractionation and bioactivities of phenolic compounds from extracts of Finnish berry plants.

In order to assist developing a natural, safe food-preservative, aqueous ethanolic extracts of leaves and berries of eight Finnish berry plants were fractionated with Sephadex LH-20 column chromatography. For each fraction, phenolic compounds were analyzed with NMR, UPLC-DAD-ESI-MS and HPLC-DAD. The antioxidant activities of the fractions were investigated using oxygen radical absorbance capacity (ORAC) assay, and the antibacterial activities were evaluated against foodborne pathogens Staphylococcus aureus and Escherichia coli. Antioxidant activities of the fractions correlated highly with both the total concentration and structural feature of phenolic compounds, including both flavonoids and non-flavonoid phenolics. ORAC value correlated strongly with the concentration of (+)-catechin, (-)-epicatecin, quercetin glycosides, and anthocyanins. Increase in size and number of sugar moieties may reduce the antioxidative activities of quercetin glycosides. Type of sugar moieties may have a significant role in influencing peroxyl-radicals scavenging ability of quercetin glycosides with monosaccharides as a single sugar moieties. Most of the fractions inhibited the target microbes. S. aureus strains expressed a higher sensitivity to phenolic compounds than E. coli strains.

Antioxidative and antibacterial activities of aqueous ethanol extracts of berries, leaves, and branches of berry plants.

Phenolic compounds were extracted with food grade solvent of acidified aqueous ethanol from leaves, berries, berry press cakes, and branches of Finnish berry plants and analyzed with HPLC-DAD, UPLC-DAD-ESI-MS and NMR. In addition, press cakes from two berry species and branches from one species were also extracted and analyzed with the same methods. The antioxidant activities of the extracts were evaluated using Folin-Ciocalteau, oxygen radical absorbance capacity (ORAC), DPPH free radical scavenging, and total radical trapping antioxidant parameter (TRAP) assays. The antibacterial activities were investigated against various Gram-negative and Gram-positive foodborne pathogens. The leaf extracts showed higher antioxidative activities (3-20 fold in ORAC assay, 10-20 fold in TRAP) than the berry extracts, in association with the higher contents of phenolic compounds in the leaf extracts; Strongest anti-bacterial effects was observed in the leaf extracts of lingonberry (Vaccinium vitis-idaea), sea buckthorn (Hippophaë rhamnoides ssp. rhamnoides) and saskatoon (Amelanchier alnifolia) on Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus. However, the antibacterial efficacy varied with bacterial species and strains. The Folin-Ciocalteu, ORAC, and TRAP values was strongly correlated with the total content of flavonoids with less association shown with the content of total phenolics and flavonol glycosides. The results suggest a major contribution of pranthocyanidins and flavan-3-ols to the antioxidative activities of the extracts. The growth inhibition on Staphylococcus aureus and Bacillus cereus was clearly associated with the content of total phenolics and ellagitannins.

Red/Green Currant and Sea Buckthorn Berry Press Residues as Potential Sources of Antioxidants for Food Use.

The potential for using extracts of press residues from black, green, red, and white currants and from sea buckthorn berries as sources of antioxidants for foods use was investigated. Press residues were extracted with ethanol in four consecutive extractions, and total Folin-Ciocalteu (F-C) reactive material and authentic phenolic compounds were determined. Radical quenching capability and mechanisms were determined from total peroxyl radical-trapping antioxidant capacity (TRAP) and oxygen radical absorbance capacity (ORAC) assays and from diphenylpicrylhydrazyl (DPPH) kinetics, respectively; specific activities were normalized to F-C reactive concentrations. Levels of total F-C reactive materials in press residue extracts were higher than in many fruits and showed significant radical quenching activity. Black currant had the highest authentic phenol content and ORAC, TRAP, and DPPH reactivity. Sea buckthorn grown in northern Finland showed extremely high total specific DPPH reactivity. These results suggest that berry press residues offer attractive value-added products that can provide antioxidants for use in stabilizing and fortifying foods.