Sourdough fermented bread has been suggested to have beneficial health effects, in part mediated ... more Sourdough fermented bread has been suggested to have beneficial health effects, in part mediated by increased satiety in the postprandial phase, but only limited research has been conducted to verify this. The current study aimed to investigate the effect of the amounts of sourdough and rye in soft bread on postprandial appetite. On 6 occasions, 23 healthy volunteers consumed 5 different test breads, with varying amount of rye and sourdough, and a yeast-fermented refined wheat control bread as part of a breakfast meal. The sourdough ranged between 9–51% of dough weight and rye content between 35–48% of flour weight. Appetite was recorded using visual analogue scales from immediately before breakfast and every 30 min the following 4 h. An ad libitum lunch was served 4 h after the breakfast meal, from which voluntary energy intake was measured. While some of the test breads resulted in lower hunger ratings and increased sense of fullness compared to the refined wheat bread, there were...
A wild-type Saccharomyces cerevisiae, strain CBS 7764, isolated from the intestine of rainbow tro... more A wild-type Saccharomyces cerevisiae, strain CBS 7764, isolated from the intestine of rainbow trout, was analyzed with respect to general growth parameters and global protein expression. Characterization of this strain was of interest since previous data show non-typical S. cerevisiae cell surface properties and because data suggest a probiotic potential of CBS 7764. The heat production rate (dQ/dt), monitored by microcalorimetry, showed that the typical growth phases resulting from diauxic growth on glucose were present in the fish isolate. However, CBS 7764 differentiated from a reference strain by becoming limited in the respiratory phase as demonstrated by a plateau in the dQ/dt signal. The global protein expression, as studied by two-dimensional gel electrophoresis (2D-PAGE), revealed a large degree of resemblance of the fish isolate to the reference strain, however, also clear qualitative and quantitative expression differences were detected; e.g. 14% of the proteins differed in expression level by a factor of at least 2. In addition, the fish isolate expressed 12 unique proteins. The heat shock proteins, which for other organisms have been identified as important in mucosal colonization, were generally expressed to a higher level in CBS 7764.
Phytases are nutritionally important for increased bioavailability of dietary minerals and phosph... more Phytases are nutritionally important for increased bioavailability of dietary minerals and phosphate for monogastric animals including humans. Release of minerals and phosphate is accomplished by the enzymatic stepwise degradation of phytate (inositol hexaphosphate, IP6). Activity determinations of phytase is often based on analysis of total released phosphate (Pi), but phytase activity in its purest form represents released product per time from IP6 only. Microbial and plant preparations often also contain mixtures of phosphatases and organic phosphate compounds; hence some released phosphate in enzymatic assays may originate from non-phytase phosphatases degrading non-phytate molecules. Moreover, even purified enzyme extracts assessed via Pi release may result in errors, since commercial IP6 commonly contains contamination of lower inositol phosphates, and further, the products of phytase IP6 hydrolysis are also substrates for the phytase. These facts motivate a quantitative compa...
Whole sorghum flour is rich in phytate, which strongly binds minerals preventing their absorption... more Whole sorghum flour is rich in phytate, which strongly binds minerals preventing their absorption by humans. Diets based on whole sorghum has therefore been associated with high prevalence of iron and zinc deficiencies in low-income countries. To improve iron absorption, the phytate content needs to be degraded to a phytate:iron molar ratio <1, and for an improved zinc absorption, a phytate:zinc molar ratio <15. Our study aims at finding conditions which effectively reduce the phytate content in whole flour composite bread. The means that was applied included activation of endogenous sorghum phytase and addition of high-phytase secreting yeast Pichia kudriavzevii TY13 at optimal pH in the baking process as well as in a pre-soaking step of the whole sorghum flour. The phytate content was analysed using high performance ion chromatography (HPIC). The initial phytate content in the composite flour was 5.3 μmol/g, that was reduced to 0.85 μmol/g in the composite bread after fermen...
Many studies suggest anthocyanins may prevent the development of several diseases. However, antho... more Many studies suggest anthocyanins may prevent the development of several diseases. However, anthocyanin bioactivity against cellular stress is not fully understood. This study aimed to evaluate the protective effect of berry anthocyanins on stressed cells using Saccharomyces cerevisiae. The impact of in vitro gastrointestinal digestion on anthocyanin profiles was also assessed. Bilberry and blackcurrant had higher anthocyanin levels than raspberry and strawberry, but digestion reduced the detected anthocyanins by approximately 90%. Yeast cells with and without digested or nondigested anthocyanin extracts were exposed to H2O2 and examined for survival. In the presence of anthocyanins, particularly from digested strawberry, a significant increase in cell survival was observed, suggesting that the type and levels of anthocyanins are important factors, but they also need to undergo gastrointestinal (GI) structural modifications to induce cell defence. Results also showed that cells need...
Berry fruits, such as strawberries and blueberries, are rich sources of anthocyanins. Several stu... more Berry fruits, such as strawberries and blueberries, are rich sources of anthocyanins. Several studies have been made on the impact of non-thermal treatments on safety, shelf-life and nutritional characteristics of such products, but the effects of these processes on anthocyanin stability during digestion in the gastrointestinal tract are still not completely clear. The aim of this study was to assess the recovery of anthocyanins after simulated gastrointestinal digestion of (1) strawberry samples, pre-treated with pulsed electric field (PEF) at 100 or 200 V·cm−1, prior to osmotic dehydration (OD), and (2) blueberry samples coated with chitosan and procyanidin. After digestion, a significantly higher content of cyanidin-3-O-glucoside and malvidin-3-O-glucoside was quantified by LC-MS/MS in processed strawberry and blueberry samples, compared with the controls. The highest recovery of cyanidin-3-O-glucoside was detected in digested strawberry samples osmotically dehydrated with trehal...
Folate is the generic term for a group of chemically related and biologically active forms of vit... more Folate is the generic term for a group of chemically related and biologically active forms of vitamin B9, needed by all organisms. Folic acid is the fully oxidized synthetic form of the vitamin. The chapter starts with nomenclature and chemical structure of folate forms followed by methodologies for extraction and chemical analysis of bacterial folate. Folates are unstable and susceptible to interconversion reactions so the special care needed to correctly determine folates in bacteria is discussed. Next follows folate biosynthesis, which happens commonly in plants and many microbes, including most bifidobacteria, but is absent in mammals, such as humans. Relevant genes, enzymes, and intermediate metabolites are described. Thereafter, the chapter continues to review folate metabolism, which describes cycling of different one-carbon units, using folate as vehicle, necessary for, for example, nucleic acid biosynthesis (purines and thymidine), amino acid homeostasis (glycine, serine, and methionine), and methylation of macromolecules, such as proteins and DNA, which includes epigenetic maintenance. Next follows a section on how biotechnology can be applied to produce high levels of microbial folate, to be used either as a food additive or as folate-producing probiotics. Finally, the main concerns and health implications from insufficient folate intake are described.
The goal of this project is to achieve natural biofortification of iron, zinc and folate in foods... more The goal of this project is to achieve natural biofortification of iron, zinc and folate in foods via selected yeasts. Deficiencies of iron, zinc and folate are prevalent in many parts of the world, especially where cereal based food comprises a large part of the food intake, but also in the western world where meat-free diets, such as vegetarian or vegan diets, has become more popular. Cereals contain several minerals such as iron, zinc and calcium, but it also contains the anti-nutrient phytate, which limits the bioavailability and gastrointestinal uptake of those minerals (1). Folate and mineral deficiencies are related to a range of health issues from mild to lethal (2). Deficiencies can sometimes be prevented by synthetic fortification, but this is not always a feasible solution due to e.g. availability or economy. There are also studies showing an increased risk of overdosing from synthetic supplements (3), which can lead to increased risk of developing some types of cancer (4). Fortification with synthetic folate may also mask deficiency of vitamin B12, something that can result in neurological damages (5). For mentioned reasons, it is of great significance to find ways to naturally fortify foods with folic acid, and to increase the bioavailability of the naturally present minerals in cereal based foods to limit the development of mineral deficiencies. This project focuses on natural biofortification using yeast strains that i) can degrade phytate and ii) synthetize natural folate. Yeast synthesized folates are believed to not mask vitamin B12 deficiencies (5). Phytate degrading yeasts allow natural release of minerals already present in the food matrix, hence less need for synthetic fortification and thereby less risk of overdosing.
The final catalytic deprotection in the large scale synthesis of thymopentin (Arg-Lys-Asp-Val-Tyr... more The final catalytic deprotection in the large scale synthesis of thymopentin (Arg-Lys-Asp-Val-Tyr) produced an impurity which had not previously been observed. Isolation by preparative HPLC and spectroscopic characterization led to a postulated structure of the impurity as ...
Microbial processes can influence retention of radionuclides directly or indirectly in several di... more Microbial processes can influence retention of radionuclides directly or indirectly in several different ways. Many microorganisms produce various kinds of ligands or chelating compounds to increase the bioavailability of essential elements needed for metabolism. ...
International journal of systematic and evolutionary microbiology, Jan 8, 2017
Three Gram-stain-positive, non-spore-forming, microaerophilic and fructose-6-phosphate phosphoket... more Three Gram-stain-positive, non-spore-forming, microaerophilic and fructose-6-phosphate phosphoketolase positive strains were isolated from a faecal sample of an adult subject of the emperor tamarin (Saguinus imperator). Given that the isolates revealed identical BOX PCR profiles, strain TRI 5(T) was selected as a representative and characterized further. Comparative analysis of 16S rRNA gene sequence similarity revealed that strain TRI 5(T) was closely related to Bifidobacterium saguini DSM 23967(T) (96.4 %) and to Bifidobacterium longum subsp. longum ATCC 15708 (96.2 %). Multilocus sequence analyses of five housekeeping genes showed the close phylogenetic relatedness of this strain to Bifidobacterium breve DSM 20213(T) (hsp60 94.1 %), Bifidobacteriumsaguini DSM 23967(T) (clpC 91 %), Bifidobacterium avesanii DSM 100685(T) (dnaG 80.3 %), Bifidobacterium longumsubsp. infantis ATCC 15697(T) (dnaJ 85.3 %) and Bifidobacterium longumsubsp. longum ATCC 15708 (rpoB 93 %), respectively. The ...
An in vitro digestion/Caco-2 cell model was applied to explore the impact of lactic acid (LA) fer... more An in vitro digestion/Caco-2 cell model was applied to explore the impact of lactic acid (LA) fermentation by Lactobacillus pentosus FSC1 and Leuconostoc mesenteroides FSC2 on the Fe bioavailability of carrot juice. The redox state of Fe in fermented carrot juice was also assessed as a crucial factor for absorption. LA fermentation was shown to improve mineral solubility to different extents at simulated physiological conditions: Mn (2-fold); Fe (1.5-1.7-fold); Zn (1.2-fold); Cu (1-fold). Soluble Fe2+ was increased about 16-fold by LA fermentation, and about one third of the Fe2+ remained soluble after in vitro digestion (about 4-5-fold higher than in fresh juice). Data on cell-line studies showed a 4-fold increase in the efficiency of Fe uptake, but not in transepithelial transfer by Caco2 cells, as a result of fermentation. The increases in Fe2+ level and the efficiency of cellular Fe uptake were strain-dependent. To sum up the effect on both Fe solubility and cellular uptake effi...
Sourdough fermented bread has been suggested to have beneficial health effects, in part mediated ... more Sourdough fermented bread has been suggested to have beneficial health effects, in part mediated by increased satiety in the postprandial phase, but only limited research has been conducted to verify this. The current study aimed to investigate the effect of the amounts of sourdough and rye in soft bread on postprandial appetite. On 6 occasions, 23 healthy volunteers consumed 5 different test breads, with varying amount of rye and sourdough, and a yeast-fermented refined wheat control bread as part of a breakfast meal. The sourdough ranged between 9–51% of dough weight and rye content between 35–48% of flour weight. Appetite was recorded using visual analogue scales from immediately before breakfast and every 30 min the following 4 h. An ad libitum lunch was served 4 h after the breakfast meal, from which voluntary energy intake was measured. While some of the test breads resulted in lower hunger ratings and increased sense of fullness compared to the refined wheat bread, there were...
A wild-type Saccharomyces cerevisiae, strain CBS 7764, isolated from the intestine of rainbow tro... more A wild-type Saccharomyces cerevisiae, strain CBS 7764, isolated from the intestine of rainbow trout, was analyzed with respect to general growth parameters and global protein expression. Characterization of this strain was of interest since previous data show non-typical S. cerevisiae cell surface properties and because data suggest a probiotic potential of CBS 7764. The heat production rate (dQ/dt), monitored by microcalorimetry, showed that the typical growth phases resulting from diauxic growth on glucose were present in the fish isolate. However, CBS 7764 differentiated from a reference strain by becoming limited in the respiratory phase as demonstrated by a plateau in the dQ/dt signal. The global protein expression, as studied by two-dimensional gel electrophoresis (2D-PAGE), revealed a large degree of resemblance of the fish isolate to the reference strain, however, also clear qualitative and quantitative expression differences were detected; e.g. 14% of the proteins differed in expression level by a factor of at least 2. In addition, the fish isolate expressed 12 unique proteins. The heat shock proteins, which for other organisms have been identified as important in mucosal colonization, were generally expressed to a higher level in CBS 7764.
Phytases are nutritionally important for increased bioavailability of dietary minerals and phosph... more Phytases are nutritionally important for increased bioavailability of dietary minerals and phosphate for monogastric animals including humans. Release of minerals and phosphate is accomplished by the enzymatic stepwise degradation of phytate (inositol hexaphosphate, IP6). Activity determinations of phytase is often based on analysis of total released phosphate (Pi), but phytase activity in its purest form represents released product per time from IP6 only. Microbial and plant preparations often also contain mixtures of phosphatases and organic phosphate compounds; hence some released phosphate in enzymatic assays may originate from non-phytase phosphatases degrading non-phytate molecules. Moreover, even purified enzyme extracts assessed via Pi release may result in errors, since commercial IP6 commonly contains contamination of lower inositol phosphates, and further, the products of phytase IP6 hydrolysis are also substrates for the phytase. These facts motivate a quantitative compa...
Whole sorghum flour is rich in phytate, which strongly binds minerals preventing their absorption... more Whole sorghum flour is rich in phytate, which strongly binds minerals preventing their absorption by humans. Diets based on whole sorghum has therefore been associated with high prevalence of iron and zinc deficiencies in low-income countries. To improve iron absorption, the phytate content needs to be degraded to a phytate:iron molar ratio <1, and for an improved zinc absorption, a phytate:zinc molar ratio <15. Our study aims at finding conditions which effectively reduce the phytate content in whole flour composite bread. The means that was applied included activation of endogenous sorghum phytase and addition of high-phytase secreting yeast Pichia kudriavzevii TY13 at optimal pH in the baking process as well as in a pre-soaking step of the whole sorghum flour. The phytate content was analysed using high performance ion chromatography (HPIC). The initial phytate content in the composite flour was 5.3 μmol/g, that was reduced to 0.85 μmol/g in the composite bread after fermen...
Many studies suggest anthocyanins may prevent the development of several diseases. However, antho... more Many studies suggest anthocyanins may prevent the development of several diseases. However, anthocyanin bioactivity against cellular stress is not fully understood. This study aimed to evaluate the protective effect of berry anthocyanins on stressed cells using Saccharomyces cerevisiae. The impact of in vitro gastrointestinal digestion on anthocyanin profiles was also assessed. Bilberry and blackcurrant had higher anthocyanin levels than raspberry and strawberry, but digestion reduced the detected anthocyanins by approximately 90%. Yeast cells with and without digested or nondigested anthocyanin extracts were exposed to H2O2 and examined for survival. In the presence of anthocyanins, particularly from digested strawberry, a significant increase in cell survival was observed, suggesting that the type and levels of anthocyanins are important factors, but they also need to undergo gastrointestinal (GI) structural modifications to induce cell defence. Results also showed that cells need...
Berry fruits, such as strawberries and blueberries, are rich sources of anthocyanins. Several stu... more Berry fruits, such as strawberries and blueberries, are rich sources of anthocyanins. Several studies have been made on the impact of non-thermal treatments on safety, shelf-life and nutritional characteristics of such products, but the effects of these processes on anthocyanin stability during digestion in the gastrointestinal tract are still not completely clear. The aim of this study was to assess the recovery of anthocyanins after simulated gastrointestinal digestion of (1) strawberry samples, pre-treated with pulsed electric field (PEF) at 100 or 200 V·cm−1, prior to osmotic dehydration (OD), and (2) blueberry samples coated with chitosan and procyanidin. After digestion, a significantly higher content of cyanidin-3-O-glucoside and malvidin-3-O-glucoside was quantified by LC-MS/MS in processed strawberry and blueberry samples, compared with the controls. The highest recovery of cyanidin-3-O-glucoside was detected in digested strawberry samples osmotically dehydrated with trehal...
Folate is the generic term for a group of chemically related and biologically active forms of vit... more Folate is the generic term for a group of chemically related and biologically active forms of vitamin B9, needed by all organisms. Folic acid is the fully oxidized synthetic form of the vitamin. The chapter starts with nomenclature and chemical structure of folate forms followed by methodologies for extraction and chemical analysis of bacterial folate. Folates are unstable and susceptible to interconversion reactions so the special care needed to correctly determine folates in bacteria is discussed. Next follows folate biosynthesis, which happens commonly in plants and many microbes, including most bifidobacteria, but is absent in mammals, such as humans. Relevant genes, enzymes, and intermediate metabolites are described. Thereafter, the chapter continues to review folate metabolism, which describes cycling of different one-carbon units, using folate as vehicle, necessary for, for example, nucleic acid biosynthesis (purines and thymidine), amino acid homeostasis (glycine, serine, and methionine), and methylation of macromolecules, such as proteins and DNA, which includes epigenetic maintenance. Next follows a section on how biotechnology can be applied to produce high levels of microbial folate, to be used either as a food additive or as folate-producing probiotics. Finally, the main concerns and health implications from insufficient folate intake are described.
The goal of this project is to achieve natural biofortification of iron, zinc and folate in foods... more The goal of this project is to achieve natural biofortification of iron, zinc and folate in foods via selected yeasts. Deficiencies of iron, zinc and folate are prevalent in many parts of the world, especially where cereal based food comprises a large part of the food intake, but also in the western world where meat-free diets, such as vegetarian or vegan diets, has become more popular. Cereals contain several minerals such as iron, zinc and calcium, but it also contains the anti-nutrient phytate, which limits the bioavailability and gastrointestinal uptake of those minerals (1). Folate and mineral deficiencies are related to a range of health issues from mild to lethal (2). Deficiencies can sometimes be prevented by synthetic fortification, but this is not always a feasible solution due to e.g. availability or economy. There are also studies showing an increased risk of overdosing from synthetic supplements (3), which can lead to increased risk of developing some types of cancer (4). Fortification with synthetic folate may also mask deficiency of vitamin B12, something that can result in neurological damages (5). For mentioned reasons, it is of great significance to find ways to naturally fortify foods with folic acid, and to increase the bioavailability of the naturally present minerals in cereal based foods to limit the development of mineral deficiencies. This project focuses on natural biofortification using yeast strains that i) can degrade phytate and ii) synthetize natural folate. Yeast synthesized folates are believed to not mask vitamin B12 deficiencies (5). Phytate degrading yeasts allow natural release of minerals already present in the food matrix, hence less need for synthetic fortification and thereby less risk of overdosing.
The final catalytic deprotection in the large scale synthesis of thymopentin (Arg-Lys-Asp-Val-Tyr... more The final catalytic deprotection in the large scale synthesis of thymopentin (Arg-Lys-Asp-Val-Tyr) produced an impurity which had not previously been observed. Isolation by preparative HPLC and spectroscopic characterization led to a postulated structure of the impurity as ...
Microbial processes can influence retention of radionuclides directly or indirectly in several di... more Microbial processes can influence retention of radionuclides directly or indirectly in several different ways. Many microorganisms produce various kinds of ligands or chelating compounds to increase the bioavailability of essential elements needed for metabolism. ...
International journal of systematic and evolutionary microbiology, Jan 8, 2017
Three Gram-stain-positive, non-spore-forming, microaerophilic and fructose-6-phosphate phosphoket... more Three Gram-stain-positive, non-spore-forming, microaerophilic and fructose-6-phosphate phosphoketolase positive strains were isolated from a faecal sample of an adult subject of the emperor tamarin (Saguinus imperator). Given that the isolates revealed identical BOX PCR profiles, strain TRI 5(T) was selected as a representative and characterized further. Comparative analysis of 16S rRNA gene sequence similarity revealed that strain TRI 5(T) was closely related to Bifidobacterium saguini DSM 23967(T) (96.4 %) and to Bifidobacterium longum subsp. longum ATCC 15708 (96.2 %). Multilocus sequence analyses of five housekeeping genes showed the close phylogenetic relatedness of this strain to Bifidobacterium breve DSM 20213(T) (hsp60 94.1 %), Bifidobacteriumsaguini DSM 23967(T) (clpC 91 %), Bifidobacterium avesanii DSM 100685(T) (dnaG 80.3 %), Bifidobacterium longumsubsp. infantis ATCC 15697(T) (dnaJ 85.3 %) and Bifidobacterium longumsubsp. longum ATCC 15708 (rpoB 93 %), respectively. The ...
An in vitro digestion/Caco-2 cell model was applied to explore the impact of lactic acid (LA) fer... more An in vitro digestion/Caco-2 cell model was applied to explore the impact of lactic acid (LA) fermentation by Lactobacillus pentosus FSC1 and Leuconostoc mesenteroides FSC2 on the Fe bioavailability of carrot juice. The redox state of Fe in fermented carrot juice was also assessed as a crucial factor for absorption. LA fermentation was shown to improve mineral solubility to different extents at simulated physiological conditions: Mn (2-fold); Fe (1.5-1.7-fold); Zn (1.2-fold); Cu (1-fold). Soluble Fe2+ was increased about 16-fold by LA fermentation, and about one third of the Fe2+ remained soluble after in vitro digestion (about 4-5-fold higher than in fresh juice). Data on cell-line studies showed a 4-fold increase in the efficiency of Fe uptake, but not in transepithelial transfer by Caco2 cells, as a result of fermentation. The increases in Fe2+ level and the efficiency of cellular Fe uptake were strain-dependent. To sum up the effect on both Fe solubility and cellular uptake effi...
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