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- Fredrikson, Mattias, 1969
(författare)
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Pea-Protein Products for Food Applications Methods for Improving Iron and Zinc Availability
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The thesis deals with some aspects of and possibilities for the production of pea protein with improved nutritional and physiological qualities. The improved pea protein can be used as a beneficial alternative to soya protein in food applications, such as infant formula. Methods for pea-protein dephytinisation by phytase enzymes were examined, in order to obtain pea protein with a high availability of iron and zinc. The removal of oligosaccharides by ultra-filtration was evaluated, to improve the physiological quality of the pea protein. To achieve fast phytate degradation in pea seeds, these have to be milled into flour. The endogenous pea-phytase enzyme can almost completely degrade the phytate in 10 hours, by soaking the pea flour at pH 7.5 and 45°C. The natural synthesis of the phytase enzymes by microorganisms is not sufficient for use in large-scale dephytinisation of pea protein. The expression of phytases in microorganisms is shown to be controlled by complex and hitherto unknown systems. It has not yet been shown whether lactic acid bacteria have the ability to produce phytase. For dephytinisation of pea-protein isolate in industrial production the addition of exogenous phytase enzyme is recommended. Complete phytate degradation was thereby obtained within 1-2 hours. Ultra-filtration by 50 or 100 kD cut-off was an effective method to remove oligosaccharides. Standard pea-protein isolate and dephytinised pea-protein isolate worked well for the production of liquid infant-formula. The new pea-protein infant formulas were evaluated for iron and zinc availability. An ion chromatography method for the simultaneous determination of Cu, Ni, Zn, Co, Mn and Fe in samples of biological origin such as food was developed. The average detection limit is 5 ppb when using 50 µL injection volume. Sample preparations suitable for food and biological samples were also developed and evaluated. The preparation method can be chosen according to the type of sample and the mineral matrix in the sample. A dynamic gastro-intestinal digestion simulation model was used to evaluate the pea-protein infant formulas for the availability of iron and zinc. The dephytinised pea-protein infant formula showed improved iron and zinc availabilities. The availability of iron and zinc in dephytinised pea formula were 70% and 49% respectively, compared with standard pea formula exhibiting 49% iron and 22% zinc availabilities. In this thesis the estimation of iron availability is compared for the first time with iron absorption from identical meals in humans. The results obtained with the digestion model are in agreement with the human absorption results. Furthermore, the possibility of combining the gastro-intestinal simulation model and Caco-2 cells is shown, thereby obtaining an in vitro simulation of both the human digestive and absorption systems. The results for iron availability suggest that pea protein may be a nutritionally beneficial alternative to soya protein for infant-formula application.
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| 2. |
- Fredrikson, Mattias, 1969, et al.
(författare)
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Phytate content and phytate degradation by endogenous phytase in pea (Pisum sativum)
- 2001
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Ingår i: Journal of the Science of Food and Agriculture. - : Wiley. - 1097-0010 .- 0022-5142. ; 81:12, s. 1139-1144
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Tidskriftsartikel (refereegranskat)abstract
- In order to rapidly reduce the content of inositol tri-hexaphosphates in pea flour by action of the endogenous phytase, raw materials as well as incubation conditions have been evaluated. The phytate (inositol hexaphosphate) content was analysed in 27 pea varieties; the influence of storage time and the difference in phytate content between the germ and the cotyledon were determined. Furthermore, degradation of inositol phosphates by the endogenous phytase enzyme was studied in pea flour, germ and cotyledon. To find the maximum phytate degradation, the effects of temperature and pH during pea flour incubation were investigated. The most efficient phytate degradation in pea flour incubation was achieved at pH 7.5 and 45 degreesC. At this condition an almost complete degradation of phytate and a 66% reduction in the sum of inositol hexa-, penta-, tetra- and triphosphates were reached in 10h. The storage time of pea seeds or removal of the germ did not have a major effect on the phytate content. Since several inositol pentaphosphate isomers were produced during phytate degradation, it can be concluded that peas contain several phytate-degrading enzymes, or one phytate-degrading enzyme with unspecific initial hydrolysation pattern.
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| 3. |
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| 4. |
- Fredrikson, Mattias, 1969, et al.
(författare)
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Production process for high-quality pea-protein isolate with low content of oligosaccharides and phytate
- 2001
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 49:3, s. 1208-1212
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Tidskriftsartikel (refereegranskat)abstract
- A process for pea-protein isolate production, resulting in low content of phytate and oligosaccharides, has been developed. Oligosaccharides were removed from the protein fraction through ultrafiltration. Ultrafiltration of 50- and 100-kD molecular-weight cutoffs (MWCOs) were tested, and both effectively separated the oligosaccharides from the protein. Phytate degradation was achieved by incubation of the pea-protein solution by addition of exogenous phytase enzyme. An almost complete degradation of inositol hexa-, penta-, tetra-, and triphosphates was reached using an incubation time of 1 h. The reduced content of oligosaccharides and inositol phosphates is likely to result in reduced flatulence and improved mineral bioavailability. These qualities of the pea-protein isolate make it a suitable protein source for infant formula production.
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| 6. |
- Nasr, Patrik, 1987-, et al.
(författare)
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The Amount of Liver Fat Predicts Mortality and Development of Type 2 Diabetes in Non-alcoholic Fatty Liver Disease.
- 2020
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Ingår i: Liver international. - : John Wiley & Sons. - 1478-3223 .- 1478-3231. ; 40:5, s. 1069-1078
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: Non-alcoholic fatty liver disease (NAFLD) is a risk factor for development of type 2 diabetes mellitus (T2DM). We aimed to evaluate whether conventional histological grading of steatosis and accurate quantification of fat content in liver biopsies using stereological point counting (SPC) can predict mortality and future development of T2DM in NAFLD patients.METHODS: 129 patients with biopsy proven NAFLD, enrolled between 1988 and 1992, were re-evaluated on two occasions, after 13.7 (±1.5) and 23.2 (±6.8) years. In patients accepting to undergo the procedure, repeat liver biopsies were performed on each follow-up and were evaluated with conventional histopathological methodology and SPC.RESULTS: Of the 106 patients without T2DM at baseline, 66 (62%) developed T2DM during a mean follow-up of 23.2 (± 6.8) years. Steatosis grade and liver fat measured with SPC independently (adjusted for age, BMI, fibrosis stage) predicted development of T2DM with an aHR of 1.60 per grade and 1.03 for each SPC percentage increase, respectively. Overall mortality and development of T2DM was more common in patients with grade 3 steatosis compared to lower grades of steatosis. Liver fat measured with SPC was significant for overall mortality (aHR 1.04). In patients that underwent repeat biopsy, reduction of liver fat measured with SPC was associated with decreased risk of developing T2DM (aHR 0.91 for each SPC percentage decrease).CONCLUSION: Steatosis grade and liver fat measured with SPC predict mortality and the risk of developing T2DM in NAFLD. Reduction of liver fat decreases the risk of developing T2DM.
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