| 1. |
- Harrysson, Hanna, 1987, et al.
(författare)
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Effect of storage conditions on lipid oxidation, nutrient loss and colour of dried seaweeds, Porphyra umbilicalis and Ulva fenestrata, subjected to different pretreatments
- 2021
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Ingår i: Algal Research. - : Elsevier BV. - 2211-9264. ; 56
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Tidskriftsartikel (refereegranskat)abstract
- Here we evaluated the levels of lipid oxidation products, fatty acids, ascorbic acid and colour of Porphyra and Ulva after oven-drying at 40 degrees C, and during subsequent storage for >= 370 days under light, semi-light and dark conditions. Part of the seaweed was pre-soaked in freshwater or pre-coated with a whey protein mixture. Controls consisted of freeze-dried seaweeds. Throughout storage there was a moderate development of the lipid oxidation-derived aldehydes, malondialdehyde, 4-hydroxy-trans-2-hexenal and 4-hydroxy-trans-2-nonenal, while there was a great loss of unsaturated fatty acids and ascorbic acid. Light storage and freeze-drying stimulated the fatty acid loss as well as pigment bleaching, seen as increased a*-values. For Ulva, the coating reduced malondialdehyde, 4-hydroxy-trans-2-hexenal and 4-hydroxy-trans-2-nonenal formation during drying and slightly prevented loss of polyunsaturated fatty acids during light storage. Pre-soaking in freshwater had no effect on the seaweed stability, although it reduced the ash content and thereby increased the relative content of ascorbic acid and fatty acids of the biomasses.
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| 2. |
- Wu, Haizhou, 1987, et al.
(författare)
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Pro-oxidative activity of trout and bovine hemoglobin during digestion using a static in vitro gastrointestinal model
- 2022
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Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 393:1
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Tidskriftsartikel (refereegranskat)abstract
- The degradation of trout and bovine hemoglobin (Hb) and their pro-oxidant activities in washed cod muscle mince (WCM) were studied using simple pH-shifts to simulate gastrointestinal (GI) conditions (pH 7 → 6 → 3 → 7), as well as full static in vitro GI digestion. Following gastric acidification to pH 6, metHb formation increased, especially for trout Hb. Subsequent acidification to pH 3 promoted Hb unfolding and partial or complete heme group-loss. During full GI digestion, polypeptide/peptide analyses revealed more extensive Hb-degradation in the gastric than duodenal phase, without any species-differences. When digesting WCM +/-Hb, both Hbs strongly promoted malondialdehyde (MDA), 4-hydroxy-2-hexenal (HHE), and 4-hydroxy-2-nonenal (HNE) formation, peaking at the end of the gastric phase. Trout-Hb stimulated MDA and HHE more than bovine Hb in the first gastric phase. Altogether, partially degraded Hb, and/or free hemin -both mammal and fish-derived- stimulated oxidation of PUFA-rich lipids under GI-conditions, especially gastric ones.
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| 3. |
- Grundy, Myriam M.L., et al.
(författare)
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INFOGEST inter-laboratory recommendations for assaying gastric and pancreatic lipases activities prior to in vitro digestion studies
- 2021
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Ingår i: Journal of Functional Foods. - : Elsevier BV. - 1756-4646. ; 82
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Tidskriftsartikel (refereegranskat)abstract
- In vitro digestion studies often use animal digestive enzyme extracts as substitutes of human gastric and pancreatic secretions. Pancreatin from porcine origin is thus commonly used to provide relevant pancreatic enzymes such as proteases, amylase and lipase. Rabbit gastric extracts (RGE) have been recently introduced to provide gastric lipase in addition to pepsin. Before preparing simulated gastric and pancreatic extracts with targeted enzyme activities as described in in vitro digestion protocols, it is important to determine the activities of enzyme preparations using validated methods. The purpose of this inter-laboratory study within the INFOGEST network was to test the repeatability and reproducibility of lipase assays using the pH-stat technique for measuring the activities of gastric and pancreatic lipases from various sources. Twenty-one laboratories having different pH-stat devices received the same protocol with identical batches of RGE and two pancreatin sources. Lipase assays were performed using tributyrin as a substrate and three different amounts (50, 100 and 200 µg) of each enzyme preparation. The repeatability results within individual laboratories were satisfactory with coefficients of variation (CVs) ranging from 4 to 8% regardless of the enzyme amount tested. However, the inter-laboratory variability was high (CV > 15%) compared to existing standards for bioanalytical assays. We identified and weighted the contributions to inter-laboratory variability of several parameters associated with the various pH-stat equipment used in this study (e.g. reaction vessel volume and shape, stirring mode and rate, burette volume for the automated delivery of sodium hydroxide). Based on this, we established recommendations for improving the reproducibility of lipase assays using the pH-stat technique. Defining accurate and complete recommendations on how to correctly quantify activity levels of enzyme preparations is a gateway to promising comparison of in vitro data obtained from different laboratories following the same in vitro digestion protocol.
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| 4. |
- Larsson, Karin, 1979, et al.
(författare)
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Malondialdehyde and 4-hydroxy-2-hexenal are formed during dynamic gastrointestinal in vitro digestion of cod liver oils.
- 2016
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Ingår i: Food and Function. - : Royal Society of Chemistry (RSC). - 2042-6496 .- 2042-650X. ; 7:8, s. 3458-3467
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Tidskriftsartikel (refereegranskat)abstract
- Marine long-chain polyunsaturated fatty acids (LC n-3 PUFA) are associated with reduced risk for inflammatory diseases, such as cardiovascular diseases and rheumatoid arthritis. These fatty acids, however, are rapidly oxidized, generating highly reactive malondialdehyde (MDA), 4-hydroxy-2-hexenal (HHE) and 4-hydroxy-2-nonenal (HNE). These oxidation products may interact with DNA and proteins, thus possibly leading to impaired cell functions. Little is known about the formation of MDA, HHE and HNE in fish oil in the gastrointestinal (GI) tract. In this study, the effect of dynamic in vitro digestion of cod liver oil on the generation of MDA, HHE and HNE was evaluated using the TNO Gastro-Intestinal Model (tiny-TIM). Effects of pre-formed oxidation products, pre-emulsification of the oil, and addition of oxidants (EDTA and hemoglobin, Hb) on GI oxidation were evaluated. Formation of aldehydes occurred during GI digestion. However, only emulsified oil fortified with 11.5 μM Hb oxidized to a degree that overcame the dilution induced by gastric secretion, which caused increased aldehyde concentrations in gastric lumen up to 90 min. The maximum levels of aldehydes generated in this study were 24.5 μM MDA, 1.6 μM HHE and 0.07 μM HNE. Oils containing different amounts of pre-formed lipid oxidation products maintained the same oxidation ranking order during digestion, even though the relative changes were not directly proportional. Emulsification of the oil had an unclear effect in the gastric phase, but a pro-oxidative effect in the intestinal phase. In general, higher aldehyde levels were reached in the intestinal lumen than in the initial meal, demonstrating that GI digestion promotes oxidation. Hence, epithelial cells may be exposed to elevated amounts of reactive aldehydes for several hours after a meal containing fish oil.
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| 5. |
- Tullberg, Cecilia, 1987, et al.
(författare)
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Effects of marine oils, digested with human fluids, on cellular viability and stress protein expression in human intestinal Caco-2 cells
- 2017
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Ingår i: Nutrients. - : MDPI AG. - 2072-6643 .- 2072-6643. ; 9:11, s. 1213-
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Tidskriftsartikel (refereegranskat)abstract
- In vitro digestion of marine oils has been reported to promote lipid oxidation, including the formation of reactive aldehydes (e.g., malondialdehyde (MDA) and 4-hydroxy-2-hexenal (HHE)). We aimed to investigate if human in vitro digestion of supplemental levels of oils from algae, cod liver, and krill, in addition to pure MDA and HHE, affect intestinal Caco-2 cell survival and oxidative stress. Cell viability was not significantly affected by the digests of marine oils or by pure MDA and HHE (0–90 ?M). Cellular levels of HSP-70, a chaperone involved in the prevention of stress-induced protein unfolding was significantly decreased (14%, 28%, and 14% of control for algae, cod and krill oil, respectively; p ? 0.05). The oxidoreductase thioredoxin-1 (Trx-1) involved in reducing oxidative stress was also lower after incubation with the digested oils (26%, 53%, and 22% of control for algae, cod, and krill oil, respectively; p ? 0.001). The aldehydes MDA and HHE did not affect HSP-70 or Trx-1 at low levels (8.3 and 1.4 ?M, respectively), whilst a mixture of MDA and HHE lowered Trx-1 at high levels (45 ?M), indicating less exposure to oxidative stress. We conclude that human digests of the investigated marine oils and their content of MDA and HHE did not cause a stress response in human intestinal Caco-2 cells.
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| 6. |
- Tullberg, Cecilia, 1987, et al.
(författare)
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Formation of reactive aldehydes (MDA, HHE, HNE) during the digestion of cod liver oil: comparison of human and porcine in vitro digestion models
- 2016
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Ingår i: Food and Function. - : Royal Society of Chemistry (RSC). - 2042-6496 .- 2042-650X. ; 7:3, s. 1401-1412
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we investigated lipid oxidation of cod liver oil during gastrointestinal (GI) digestion using two types of in vitro digestion models. In the first type of model, we used human GI juices, while we used digestive enzymes and bile from porcine origin in the second type of model. Human and porcine models were matched with respect to factors important for lipolysis, using a standardized digestion protocol. The digests were analysed for reactive oxidation products: malondialdehyde (MDA), 4-hydroxy-trans-2-nonenal (HNE), and 4-hydroxy-trans-2-hexenal (HHE) by liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (LC/APCI-MS), and for free fatty acids (FFA) obtained during the digestion by gas chromatography-mass spectrometry (GC-MS). The formation of the oxidation products MDA, HHE, and HNE was low during the gastric digestion, however, it increased during the duodenal digestion. The formation of the oxidation products reached higher levels when digestive juices of human origin were used (60 μM of MDA, 0.96 μM of HHE, and 1.6 μM of HNE) compared to when using enzymes and bile of porcine origin (9.8, and 0.36 μM of MDA; 0.16, and 0.026 μM of HHE; 0.23, and 0.005 μM of HNE, respectively, in porcine models I and II). In all models, FFA release was only detected during the intestinal step, and reached up to 31% of total fatty acids (FA). The findings in this work may be of importance when designing oxidation oriented lipid digestion studies.
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| 7. |
- Tullberg, Cecilia, 1987
(författare)
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Oxidation of marine oils during in vitro gastrointestinal digestion and its effects on stress in human intestinal Caco-2 cells
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Marine oils are attracting public interest due to the preventive effects, e.g., on inflammation, which are linked to the long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs). However, LC n-3 PUFAs are highly susceptible to oxidation, which could interfere with their positive effects. It has been shown in vitro that marine lipids not only oxidize during storage, but also during gastrointestinal (GI) digestion. Little is so far known about the marine lipid oxidation reaction under human GI conditions. In this work, oxidation of marine oils during in vitro GI digestion was investigated targeting the highly reactive lipid oxidation products malondialdehyde (MDA), 4-hydroxy-trans-2-hexenal (HHE), and 4-hydroxy-trans-2-nonenal (HNE); all three with documented carcinogenic and genotoxic properties. Variables studied during the digestions were; source of the GI-fluids (porcine/human), presence of additional gastric lipase (from rabbit) or addition of a lipase inhibitor, type of in vitro model (static/dynamic),physical status (bulk/emulsified), oxidation status and origin of the marine oil, as well as additions of food-derived pro- and antioxidants. Furthermore, effects from marine oil digests related to intestinal cell stress were studied. Aldehyde levels increased over time in the intestinal phase during digestion of cod liver oil, in a static in vitro digestion model with human digestive fluids (HDF) or simulated digestive fluids (SDF, i.e., electrolyte solution with enzymes and bile of porcine origin). The highest aldehyde levels were reached during the intestinal phase (t=210 min) using HDF (60 µM of MDA, 0.96 µM of HHE, and 1.6 µM of HNE). In the static model with HDF, lipolysis was found to correlate positively to lipid oxidation, as shown when adding rabbit gastric lipase or orlistat, a lipase inhibitor, to cod liver oil. Aldehydes also increased during digestion of cod liver oil in a dynamic digestion model (tiny-TIM) with SDF. Cod liver oil having a higher degree of oxidation at start of the digestion reached higher levels of aldehydes during GI conditions compared to non-oxidized oils. Pre-emulsification of cod liver oil was slightly protective in the gastric phase, but had a pro-oxidative effect during the intestinal phase. Addition of fish hemoglobin (Hb) as a pro-oxidant to emulsified cod liver oil strongly promoted aldehyde formation, while the metal chelator EDTA had a protective effect during gastric digestion. Industrially relevant levels of tocopherols (α-tocopherol, and Covi-ox® T 70 EU; 4.5 mg/g oil) were protective to cod liver oil oxidation in the static in vitro digestion model with HDF. In the same model, detected aldehyde levels in intestinal digests from four different marine oils were ranked as: cod liver oil ~ whole fish oil >> krill oil ~microalgae oil. To study cellular effects of GI oxidation, a cultured human intestinal epithelium (Caco-2 cell line) was treated with cod liver-, fish-, and algae oil digests, and corresponding levels of pure MDA and HHE (0-90 µM). Cell viability was not affected by the digests, nor their levels of MDA and HHE. Stress-related proteins were not found to increase upon exposure to digests or aldehydes, rather the opposite. To summarize, MDA, HHE, HNE were formed during in vitro GI digestion of marine oils in all the models tested; absolute levels were, however, affected by pre-treatment of the oils, and were higher with HDF than SDF. Although bulk oils digested without added pro- or antioxidants did not induce a stress response in the Caco-2 cells, studies in humans are needed to be able to say if the absence of stress effects from aldehydes or other oxidation products can be translated to in vivo conditions.
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| 8. |
- Tullberg, Cecilia, 1987, et al.
(författare)
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Oxidation of marine oils during in vitro gastrointestinal digestion with human digestive fluids – Role of oil origin, added tocopherols and lipolytic activity
- 2019
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Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 270, s. 527-537
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Tidskriftsartikel (refereegranskat)abstract
- The formation of malondialdehyde (MDA), 4-hydroxy-2-hexenal (HHE), 4-hydroxy-2-nonenal (HNE), and 4-oxo-2-nonenal (ONE) in cod liver-, anchovy-, krill-, and algae oil during in vitro digestion with human gastrointestinal fluids was investigated. Adding rabbit gastric lipase, lipase inhibitor (orlistat) and tocopherols to cod liver oil, lipolysis and oxidation was also studied. Among the marine oils, the highest aldehyde levels (18 µM MDA, 3 µM HHE and 0.2 µM HNE) were detected after digestion of cod liver oil, while the lowest levels were detected in krill and algae oils. Addition of rabbit gastric lipase significantly increased the release of HNE during the digestion. Orlistat significantly reduced lipolysis and MDA formation. Formation of MDA and HHE was delayed by tocopherols, the tocopherol mix Covi-ox® T 70 EU being more effective than pure α-tocopherol.
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| 9. |
- Tullberg, Cecilia, 1987, et al.
(författare)
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Oxidative stability during digestion
- 2021
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Ingår i: Omega-3 Delivery Systems: Production, Physical Characterization and Oxidative Stability. ; , s. 449-479, s. 449-479
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter focuses on the oxidative stability of n-3 polyunsaturated fatty acids (n-3 PUFAs) delivery systems and n-3 PUFAs fortified foods during digestion, with specific attention given to the long-chain n-3 PUFAs. The topic is of importance since the formation of reactive lipid oxidation products in the gastrointestinal tract (GIT) can lead to unwanted reactions e.g., with proteins, phospholipids, and DNA of the intestinal epithelial layer as well as decrease the amount of n-3 PUFAs being bioavailable in the GIT. Initially, the use of in vitro digestion models to study lipid oxidation is reviewed, after which available literature about the susceptibility of different n-3 PUFA delivery systems—neat oils, emulsions, capsules, and n-3 PUFA-rich foods—to oxidation in the GIT is summarized. In the next part of the chapter, the link between digestion-induced oxidation and initial oxidative status of the n-3 PUFA system, the degree of lipolysis as well as the presence of different pro- and antioxidants is discussed. Based on available findings, some future directions in the current research area are finally given.
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| 10. |
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