| 1. |
- Burri, Stina
(författare)
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Antioxidants as potential anti-inflammatory components in processed meat products
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In 2015, the World health organisation (WHO) released a press statement together with the International Agency for Research in Cancer (IARC) classifying processed meat as carcinogenic. Since then, research in this area has been focused on finding the underlying mechanism(s) responsible for the link between processed meat and the increased prevalence of colorectal cancer. One of the main hypotheses is that the heme iron present in the meat catalyses lipid oxidation which increases the levels of Reactive Oxygen Species (ROS) and toxic lipid oxidation secondary products which are harmful to our health.This thesis focuses on this lipid oxidation reaction, and the inhibition thereof, to gain further knowledge in the etiology of colorectal cancer caused by consumption of processed meat products. First, sustainable plant antioxidants were screened for their efficiency and content. Next, a commonly consumed meat product was manufactured based on its proneness to oxidise. When this was done, the most efficient antioxidants previously screened were added to these meat products for inhibition of lipid oxidation. And finally, the five most efficientantioxidants were tested in meatballs, together with relevant controls, for health evaluating purposes in an in vivo trial.We found several natural antioxidants which effectively decreased the level of lipid oxidation in our meat product. For instance, a freeze-dried summer savory (Satureja hortensis L.) powder, decreased the level of lipid oxidation to 13.8 % compared to the meat product with no added antioxidants at 200 ppm concentration. A water extract of sea buckthorn (Hippophae rhamnoides L.) leaves and sprouts lowered the oxidation to 22.9 % at 100 ppm concentration. However, we also found some antioxidants with highly pro-oxidant properties in a meat model pretrial. This is of importance, showing the great complexity of both antioxidants and matrices studied. As for the in vivo trial, some differences between trial groups were found. However, the results from this screening wereunfortunately not as conclusive as we expected, but gave nonetheless great inspiration and knowledge for further studies in the area. It is clear that lipid oxidation is not the sole mechanism behind the increase in colorectalcancer prevalence amongst processed meat consumers, but important differences could be seen in mice after only four months of trial in terms of microflora composition and certain immunological reactions between trialgroups.
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| 2. |
- Burri, Stina C.M., et al.
(författare)
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Antioxidant capacity and major phenol compounds of horticultural plant materials not usually used
- 2017
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Ingår i: Journal of Functional Foods. - : Elsevier BV. - 1756-4646. ; 38, s. 119-127
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Tidskriftsartikel (refereegranskat)abstract
- Horticultural plant materials not usually used from onion, carrot, beetroot, sea buckthorn, black and red currants as well as a wastewater powder from olive oil production were analyzed for total phenols content (FC), ferric reducing ability of plasma (FRAP), radical scavenging capacity (ABTS), and for major phenolic compounds by HPLC-MS. Antioxidant capacity and phenol content varied significantly between species and cultivars, with extracts of sea buckthorn leaves being superior. In different species, different phenolic compounds were closely associated with FRAP, ABTS and FC. For instance, hydrolysable tannins were major antioxidants in sea buckthorn whereas quercetin was the major antioxidant in onion peel and skin. This study shows that horticultural plant materials usually left in the field or waste materials from processing may have high antioxidant properties, and that extracts of these materials therefore could be of potential interest for development of antioxidant food additives.
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| 3. |
- Burri, Stina C.M., et al.
(författare)
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Lipid oxidation inhibition capacity of 11 plant materials and extracts evaluated in highly oxidised cooked meatballs
- 2019
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Ingår i: Foods. - : MDPI AG. - 2304-8158. ; 8:9
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Tidskriftsartikel (refereegranskat)abstract
- The underlying mechanism(s) behind the potential carcinogenicity of processed meat is a popular research subject of which the lipid oxidation is a common suspect. Different formulations and cooking parameters of a processed meat product were evaluated for their capacity to induce lipid oxidation. Meatballs made of beef or pork, containing different concentrations of fat (10 or 20 g 100 g−1), salt (2 or 4 g 100 g−1), subjected to differing cooking types (pan or deep frying), and storage times (1, 7, and 14 days), were evaluated using thiobarbituric reactive substances (TBARS). The deep-fried meatball type most susceptible to oxidation was used as the model meat product for testing the lipid oxidation inhibiting capacity of 11 plant materials and extracts, in two concentrations (100 and 200 mg kg−1 gallic acid equivalent (GAE)), measured after 14 days of storage using TBARS. Summer savory lyophilized powder was the most efficient plant material, lowering lipid oxidation to 13.8% and 21.8% at the 200 and 100 mg kg−1 concentration, respectively, followed by a sea buckthorn leaf extract, lowering lipid oxidation to 22.9% at 100 mg kg−1, compared to the meatball without added antioxidants. The lipid oxidation was thus successfully reduced using these natural antioxidants.
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| 4. |
- Burri, Stina C.M., et al.
(författare)
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Lipid oxidation inhibition capacity of plant extracts and powders in a processed meat model system
- 2020
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Ingår i: Meat Science. - : Elsevier BV. - 0309-1740 .- 1873-4138. ; 162
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Tidskriftsartikel (refereegranskat)abstract
- A meat model system was used for screening lipid oxidation inhibiting capacity of diverse horticultural plant materials. In the model, heme-containing sarcoplasmic proteins from the meat water-phase were homogenized with linoleic acid and thiobarbituric reactive substances (TBARS) were measured. 23 Plant materials were investigated at three high (50, 100, and 200 ppm) concentrations and five plant extracts were tested at three low (5, 10, and 20 ppm) concentrations over time. In the high concentration sets, summer savory freeze-dried powder, beetroot leaves extracted with 50% ethanol, and an olive polyphenol powder extracted from wastewater, inhibited oxidation the most effectively. After two weeks and at 200 ppm concentration, oxidation was reduced to 17.2%, 16.6% and 13.5% of the blank sample with no added antioxidants respectively. In the low concentration set, spray dried rhubarb juice inhibited oxidation the most after two weeks at 5 ppm where oxidation was reduced to 68.3% of the blank sample with no added antioxidants.
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| 5. |
- Burri, Stina, et al.
(författare)
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Processed meat products with added plant antioxidants affect the microbiota and immune response in C57BL/6JRj mice with cyclically induced chronic inflammation
- 2021
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Ingår i: Biomedicine and Pharmacotherapy. - : Elsevier BV. - 1950-6007 .- 0753-3322. ; 135
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Tidskriftsartikel (refereegranskat)abstract
- Epidemiological studies have found that there is a correlation between red and processed meat consumption and an increased risk of colorectal cancer. There are numerous existing hypotheses on what underlying mechanisms are causative to this correlation, but the results remain unclear. A common hypothesis is that lipid oxidation, which occurs in endogenous lipids and phospholipids in consumed food, are catalyzed by the heme iron in meat. In this study, five pre-selected plant antioxidant preparations (sea buckthorn leaves and sprouts, summer savory leaves, olive polyphenols, onion skin and lyophilized black currant leaves) were added to a meatball type prone to oxidize (pork meat, 20 % fat, 2% salt, deep-fried and after 2 weeks of storage). Pro-inflammatory markers, neutrophil infiltration and microbiota composition were studied after four months in a chronic inflammation model in C57BL6/J female mice. We found that the bacterial diversity index was affected, as well as initial immunological reactions.
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| 6. |
- Uhlig, Elisabeth, et al.
(författare)
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Comparative immunomodulatory effects in mice and in human dendritic cells of five bacterial strains selected for biocontrol of leafy green vegetables
- 2022
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Ingår i: Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association. - : Elsevier BV. - 1873-6351 .- 0278-6915. ; 165
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Tidskriftsartikel (refereegranskat)abstract
- The market for ready-to eat vegetables is increasing, but unfortunately so do the numbers of food-borne illness outbreaks related to these products. A previous study has identified bacterial strains suitable for biocontrol of leafy green vegetables to reduce the exposure to pathogens in these products. As a tentative safety evaluation, five selected strains (Rhodococcus cerastii MR5x, Bacillus coagulans LMG P-32205, Bacillus coagulans LMG P-32206, Pseudomonas cedrina LMG P-32207 and Pseudomonas punonensis LMG P-32204) were individually compared for immunomodulating effects in mice and in human monocyte-derived dendritic cells (MoDCs). Mice receiving the two B. coagulans strains consistently resemble the immunological response of the normal control, and no, or low, cell activation and pro-inflammatory cytokine expression was observed in MoDCs exposed to B. coagulans strains. However, different responses were seen in the two models for the Gram-negative P. cedrina and the Gram-positive R. cerastii. Moreover, P. punonensis and B. coagulans increased the microbiota diversity in mice as seen by the Shannon-Wiener index. In conclusion, the two strains of B. coagulans showed an immunological response that indicate that they lack pathogenic abilities, thus encouraging further safety evaluation and showing great potential to be used as biocontrol agents on leafy green vegetables.
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| 7. |
- Östbring, Karolina, et al.
(författare)
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Protein recovery from rapeseed press cake : Varietal and processing condition effects on yield, emulsifying capacity and antioxidant activity of the protein rich extract
- 2019
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Ingår i: Foods. - : MDPI AG. - 2304-8158. ; 8:12
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Tidskriftsartikel (refereegranskat)abstract
- Protein was recovered from five varieties and a mixed blend of cold-pressed rapeseed press cake by leaching and precipitation in a water-based process, and the protein recovery yield varied from 26–41% depending on variety. Exposure for heat during protein recovery severely reduced the rapeseed proteins’ ability to stabilize the oil–water interface of emulsion droplets. Protein extract from Lyside had the best emulsifying properties of the varieties investigated. Oxidation rate was assessed by the Thiobarbituric Acid Reactive Substances (TBARS) method and rapeseed protein extracts from Epure and Festivo had higher capacity to delay oxidation compared with soy lecithin. There are possibilities to broaden the use of rapeseed whereby recovered rapeseed protein can be used as a plant-based multifunctional ingredient with emulsifying capacity and which has a delaying effect on oxidation.
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