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  • 1.
    Cavka, Adnan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Stagge, Stefan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Jönsson, Leif J.
    Identification of Small Aliphatic Aldehydes in Pretreated Lignocellulosic Feedstocks and Evaluation of Their Inhibitory Effects on Yeast2015In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 63, no 44, p. 9747-9754Article in journal (Refereed)
    Abstract [en]

    Six lignocellulosic hydrolysates produced through acid pretreatment were analyzed for the occurrence of formaldehyde, acetaldehyde, and glycolaldehyde. Acetaldehyde was found in all six (0.3-1.6 mM) and formaldehyde in four (<= 4.4 mM), whereas glycolaldehyde was not detected. To assess the relevance of these findings, fermentations with yeast and formaldehyde or acetaldehyde were performed in the concentration interval 0.5-10 mM. Formaldehyde already inhibited at 1.0 mM, whereas 5.0 mM acetaldehyde was needed to obtain a clear inhibitory effect. After 24 h of fermentation, 1.5 mM formaldehyde reduced the glucose consumption by 85%, the balanced ethanol yield by 92%, and the volumetric productivity by 91%. The results show that formaldehyde and acetaldehyde are prevalent in pretreated lignocellulose and that formaldehyde in some cases could explain a large part of the inhibitory effects on yeast by lignocellulosic hydrolysates, as three of six hydrolysates contained >= 1.9 mM formaldehyde, which was shown to be strongly inhibitory.

  • 2.
    Chatterjee, Robin
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Johansson, Kristin
    Department of Chemical Engineering, Karlstad University, SE-651 88 Karlstad, Sweden.
    Järnström, Lars
    Department of Chemical Engineering, Karlstad University, SE-651 88 Karlstad, Sweden.
    Jönsson, Leif J
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Evaluation of the potential of fungal and plant laccases for active-packaging applications2011In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 59, no 10, p. 5390-5395Article in journal (Refereed)
    Abstract [en]

    Laccases from Trametes versicolor (TvL), Myceliophthora thermophila (MtL), and Rhus vernicifera (RvL) were investigated with regard to their potential utilization as oxygen scavengers in active packages containing food susceptible to oxidation reactions. The substrate selectivity of the laccases was investigated with a set of 17 reducing substrates, mainly phenolic compounds. The temperature dependence of reactions performed at low temperatures (4-31 °C) was studied. Furthermore, the laccases were subjected to immobilization in a latex/clay matrix and drying procedures performed at temperatures up to 105 °C. The results show that it is possible to immobilize the laccases with retained activity after dispersion coating, drying at 75-105 °C, and subsequent storage of the enzyme-containing films at 4 °C. TvL and, to some extent, MtL were promiscuous with regard to their reducing substrate, in the sense that the difference in activity with the 17 substrates tested was relatively small. RvL, on the other hand, showed high selectivity, primarily toward substrates resembling its natural substrate urushiol. When tested at 7 °C, all three laccases retained >20% of the activity they had at 25 °C, which suggests that it would be possible to utilize the laccases also in refrigerated food packages. Coating and drying resulted in a remaining enzymatic activity ranging from 18 to 53%, depending on the drying conditions used. The results indicate that laccases are useful for active-packaging applications and that the selectivity for reducing substrates is an important characteristic of laccases from different sources.

  • 3. Kaffarnik, Stefanie
    et al.
    Ehlers, Ina
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Gröbner, Gerhard
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Schleucher, Jurgen
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Vetter, Walter
    Two-Dimensional P-31,H-1 NMR Spectroscopic Profiling of Phospholipids in Cheese and Fish2013In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 61, no 29, p. 7061-7069Article in journal (Refereed)
    Abstract [en]

    Phospholipids (PLs) comprise an important lipid class in food because of their technological use as emulsifiers and their nutritional value. This study used one-dimensional P-31 NMR and two-dimensional (2D) P-31,H-1 COSY NMR spectroscopy for the determination of the PL composition of cheese and fish after liquid liquid enrichment. This extraction step enabled the identification of 10 PLs in cheese and 9 PLs in fish by 2D P-31,H-1 NMR. Variations in the P-31 shifts indicated differences in the fatty acids attached to the individual PLs. The total PL content in cheese fat and fish oil ranged from 0.3 to 0.4% and from 5 to 12%, respectively. Phosphatidylcholine was the most prominent PL in both matrices (up to 6596). Minor PLs (limit of detection = 4 nmol, i.e. 500 mu L of an 8 mu M solution) were identified in forms of phosphatidic acid, lysophosphatidic acid, and phosphatidylglycerol. Specific cross couplings and H-1 fine structures in the 2D P-31,H-1 NMR spectra proved to be valuable for the assignment and verification of known and uncommon PLs in the samples.

  • 4. Kang, Jinho
    et al.
    Choi, Moon-Young
    Kang, Sunmi
    Kwon, Hyuk Nam
    Wen, He
    Lee, Chang Hoon
    Park, Minseok
    Wiklund, Susanne
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kim, Hyo Jin
    Kwon, Sung Won
    Park, Sunghyouk
    Application of a 1H nuclear magnetic resonance (NMR) metabolomics approach combined with orthogonal projections to latent structure-discriminant analysis as an efficient tool for discriminating between Korean and Chinese herbal medicines2008In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 56, no 24, p. 11589-11595Article in journal (Refereed)
    Abstract [en]

    Correct identification of the origins of herbal medical products is becoming increasingly important in tandem with the growing interest in alternative medicine. However, visual inspection of raw material is still the most widely used method, and newer scientific approaches are needed. To develop a more objective and efficient tool for discriminating herbal origins, particularly Korean and Chinese, we employed a nuclear magnetic resonance (NMR)-based metabolomics approach combined with an orthogonal projections to latent structure-discriminant analysis (OPLS-DA) multivariate analysis. We first analyzed the constituent metabolites of Scutellaria baicalensis through NMR studies. Subsequent holistic data analysis with OPLS-DA yielded a statistical model that could cleanly discriminate between the sample groups even in the presence of large structured noise. An analysis of the statistical total correlation spectroscopy (STOCSY) spectrum identified citric acid and arginine as the key discriminating metabolites for Korean and Chinese samples. As a validation of the discrimination model, we performed blind prediction tests of sample origins using an external test set. Our model correctly predicted the origins of all of the 11 test samples, demonstrating its robustness. We tested the wider applicability of the developed method with three additional herbal medicines from Korea and China and obtained very high prediction accuracy. The solid discriminatory power and statistical validity of our method suggest its general applicability for determining the origins of herbal medicines.

  • 5. Marmon, Sofia K
    et al.
    Liljelind, Per
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Undeland, Ingrid
    Removal of lipids, dioxins, and polychlorinated biphenyls during production of protein isolates from baltic herring (Clupea harengus) using pH-shift processes2009In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 57, no 17, p. 7819-7825Article in journal (Refereed)
    Abstract [en]

    Dioxins and PCBs are toxic, lipophilic, and persistent substances that impose a serious health threat. A major risk of exposure to these toxic substances is consumption of fish from polluted waters, such as the Baltic Sea. The aim of this study was to investigate if pH-shift processing of Baltic herring with elevated toxicity levels could be used to produce a protein isolate with low fat content and, thereby, reduced dioxin and PCB levels. Both acid (pH 2.7) and alkaline (pH 11.2) pH-shift processing were investigated and resulted in efficient reduction of fat, dioxin, and PCB levels. A reduction of 70-80% per amount of protein was determined for all of these parameters. The amounts, and thus the removal, of lipids and dioxins (R(2) = 0.952) as well as lipids and PCBs (R(2) = 0.996) were highly correlated (p < 0.01). A mass balance of the alkaline pH-shift process showed that most of the fat and pollutants were found in the floating fat emulsion layer of the first centrifugation, followed by the pellet of the first centrifugation. These data show that the pH-shift protein isolation technique can be used to process herring with elevated dioxin and PCB levels and thereby increase the usage possibilities of such fish.

  • 6. Moore, John P.
    et al.
    Zhang, Song-Lei
    Nieuwoudt, Helene
    Divol, Benoit
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bauer, Florian F.
    A Multivariate Approach Using Attenuated Total Reflectance Mid-infrared Spectroscopy To Measure the Surface Mannoproteins and beta-Glucans of Yeast Cell Walls during Wine Fermentations2015In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 63, no 45, p. 10054-10063Article in journal (Refereed)
    Abstract [en]

    Yeast cells possess a cell wall comprising primarily glycoproteins, mannans, and glucan polymers. Several yeast phenotypes relevant for fermentation, wine processing, and wine quality are correlated with cell wall properties. To investigate the effect of wine fermentation on cell wall composition, a study was performed using mid-infrared (MIR) spectroscopy coupled with multivariate methods (i.e., PCA and OPLS-DA). A total of 40 yeast strains were evaluated, including Saccharomyces strains (laboratory and industrial) and non-Saccharomyces species. Cells were fermented in both synthetic MS300 and Chardonnay grape must to stationery phase, processed, and scanned in the MIR spectrum. PCA of the fingerprint spectral region showed distinct separation of Saccharomyces strains from non-Saccharomyces species; furthermore, industrial wine yeast strains separated from laboratory strains. PCA loading plots and the use of OPLS-DA to the data sets suggested that industrial strains were enriched with cell wall proteins (e.g., mannoproteins), whereas laboratory strains were composed mainly of mannan and glucan polymers.

  • 7. Spinola, Vitor
    et al.
    Llorent-Martinez, Eulogio J.
    Gouveia, Sandra
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Castilho, Paula C.
    Myrica faya: A New Source of Antioxidant Phytochemicals2014In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 62, no 40, p. 9722-9735Article in journal (Refereed)
    Abstract [en]

    Myrica faya is a fruit tree endemic of the Macaronesia (Azores, Madeira, and Canary Island), and its edible fruits are known as "amorinhos" (little loves), bright red to purple berries , used fresh and in jams and liquors. The phenolic composition and antioxidant capacity of leaves and berries from M faya are presented here for the first time. The screening of phytochemical compounds was carried out using high-performance liquid chromatography with online. UV and electrospray ionization mass spectrometric detection (HPLC-DAD-ESI-MS"). There were 55 compounds characterized, mostly galloyl esters of flavonoids and phenolic acids; 26 of the identified compounds (anthocyannis, isoflavonoids, lignans, terpenes, fatty acids, and phenylethanoids) have not been reported in Myrica genus so far. From the data presented here, it can be concluded that faya berries represent a rich source of cyanidin-3-glucoside, flavonoids, vitamin C. In fact, higher antioxidant activity than that of the well-known Myrica rubra berries (Chinese bayberry) has been observed.

  • 8. Zhang, Shuo
    et al.
    Winestrand, Sandra
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Chen, Lin
    Li, Dengxin
    Jönsson, Leif
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Hong, Feng
    Tolerance of the Nanocellulose-Producing Bacterium Gluconacetobacter xylinus to Lignocellulose-Derived Acids and Aldehydes2014In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 62, no 40, p. 9792-9799Article in journal (Refereed)
    Abstract [en]

    Lignocellulosic biomass serves as a potential alternative feedstock for production of bacterial nanocellulose (BNC), a high-value added product of bacteria such as Gluconacetobacter xylinus. The tolerance of G. xylinus to lignocellulose derived inhibitors (formic acid, acetic acid, levulinic acid, furfural, and S-hydroxymethylfurfural) was investigated. Whereas 100 mM formic acid completely suppressed the metabolism of G xylinus, 250 mM of either acetic acid or levulinic acid still allowed glucose metabolism and BNC production to occur. Complete suppression of glucose utilization and BNC production was observed after inclusion of 20 and 30 mM furfural and 5-hydroxymethylfurfural, respectively. The highest yields observed were 88% for furoic acid/furfural and 76% for 5-hydroxymethyl-2-furoic acid/5-hydroxymethylfurfural. These results are the first demonstration of the capability of G. xylinus to tolerate lignocellulose derived inhibitors and to convert furan aldehydes.

  • 9. Zietsman, Anscha J. J.
    et al.
    Moore, John P.
    Fangel, Jonatan U.
    Willats, William G. T.
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Vivier, Melane A.
    Following the compositional changes of fresh grape skin cell walls during the fermentation process in the presence and absence of maceration enzymes2015In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 63, no 10, p. 2798-2810Article in journal (Refereed)
    Abstract [en]

    Cell wall profiling technologies were used to follow compositional changes that occurred in the skins of grape berries (from two different ripeness levels) during fermentation and enzyme maceration. Multivariate data analysis showed that the fermentation process yielded cell walls enriched in hemicellulose components because pectin was solubilized (and removed) with a reduction as well as exposure of cell wall proteins usually embedded within the cell wall structure. The addition of enzymes caused even more depectination, and the enzymes unravelled the cell walls enabling better access to, and extraction of, all cell wall polymers. Overripe grapes had cell walls that were extensively hydrolyzed and depolymerized, probably by natural grape-tissue-ripening enzymes, and this enhanced the impact that the maceration enzymes had on the cell wall monosaccharide profile. The combination of the techniques that were used is an effective direct measurement of the hydrolysis actions of maceration enzymes on the cell walls of grape berry skin.

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