Publications by authors named "Roger Andersson"

50 Publications

Amylose starch with no detectable branching developed through DNA-free CRISPR-Cas9 mediated mutagenesis of two starch branching enzymes in potato.

Sci Rep 2021 Feb 22;11(1):4311. Epub 2021 Feb 22.

Department of Plant Breeding, Swedish University of Agricultural Sciences, P.O. Box 101, 23053, Alnarp, Sweden.

DNA-free genome editing was used to induce mutations in one or two branching enzyme genes (Sbe) in tetraploid potato to develop starch with an increased amylose ratio and elongated amylopectin chains. By using ribonucleoprotein (RNP) transfection of potato protoplasts, a mutation frequency up to 72% was achieved. The large variation of mutations was grouped as follows: Group 1 lines with all alleles of Sbe1 mutated, Group 2 lines with all alleles of Sbe1 as well as two to three alleles of Sbe2 mutated and Group 3 lines having all alleles of both genes mutated. Starch from lines in Group 3 was found to be essentially free of amylopectin with no detectable branching and a chain length (CL) distribution where not only the major amylopectin fraction but also the shortest amylose chains were lost. Surprisingly, the starch still formed granules in a low-ordered crystalline structure. Starch from lines of Group 2 had an increased CL with a higher proportion of intermediate-sized chains, an altered granule phenotype but a crystalline structure in the granules similar to wild-type starch. Minor changes in CL could also be detected for the Group 1 starches when studied at a higher resolution.
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http://dx.doi.org/10.1038/s41598-021-83462-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900246PMC
February 2021

A simplified method of determining the internal structure of amylopectin from barley starch without amylopectin isolation.

Carbohydr Polym 2021 Mar 13;255:117503. Epub 2020 Dec 13.

Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, SE-750 07, Uppsala, Sweden. Electronic address:

To determine the internal structure of barley starch without amylopectin isolation, whole starch was hydrolyzed using β-amylase to remove the linear amylose and obtain β-limit dextrins (β-LDs). The β-LDs were treated with extensive α-amylase to prepare α-limit dextrins (α-LDs), and the α-LDs were further hydrolyzed with β-amylase into building blocks. The chain-length distribution of β-LD and building block composition were analyzed by size-exclusion chromatography and anion-exchange chromatography. The internal structure of the barley whole starches had similar pattern to barley amylopectins analyzed by conventional methods. The starch of barley amo1-mutated varieties contained more short internal B-chains and less long internal B-chains than that of other varieties. The starch from amo1-mutated varieties had more large building blocks than that from waxy varieties. The simplified method presented in this study can effectively characterize starch internal structure that relates to physicochemical properties of starch, although some details of amylopectin structure are not assessable.
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http://dx.doi.org/10.1016/j.carbpol.2020.117503DOI Listing
March 2021

Dietary fiber components, microstructure, and texture of date fruits (Phoenix dactylifera, L.).

Sci Rep 2020 12 10;10(1):21767. Epub 2020 Dec 10.

Department of Physics, College of Science, United Arab Emirates University, Al Ain, UAE.

Date fruits vary widely in the hardness of their edible parts and they are classified accordingly into soft, semi-dry, and dry varieties. Fruit texture, a significant parameter in determining consumer acceptance, is related to the tissue structure and chemical composition of the fruit, mainly the ratio of sucrose to reducing sugars. This study aimed to understand the relationship between the chemical composition, microstructure, and texture profile of 10 major Emirati date fruits. The soluble sugars, glucose and fructose, represent ca 80 g/100 g of the fruits on the basis of dry weight (DW) while the dietary fiber contents varied 5.2-7.4 g/100 dg D.W. with lignin being the main determinant of the variability. The textures of the samples were studied using instrumental texture profile analysis. While no correlation was found between the soluble sugar and texture parameters in this study, the different fiber constituents correlated variably with the different parameters of date fruit texture. Lignin, arabinoxylan, galactomannan, and pectin were found to correlate significantly with fruit hardness and the related parameters, gumminess and chewiness. Both lignin and arabinoxylan correlated with resilience, and arabinoxylan exhibited a strong correlation with cohesiveness.
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http://dx.doi.org/10.1038/s41598-020-78713-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7728813PMC
December 2020

Side Streams of Broccoli Leaves: A Climate Smart and Healthy Food Ingredient.

Int J Environ Res Public Health 2020 04 1;17(7). Epub 2020 Apr 1.

Department of Plant breeding, Swedish University of Agricultural Sciences, SE-230 53 Alnarp, Sweden.

Human consumption of fruits and vegetables are generally below recommended levels. Waste from the production, e.g., of un-used parts such as broccoli leaves and stem when producing broccoli florets for food, is a sustainability issue. In this study, broccoli leaves were analyzed for the content of various dietary fibre and phenolics, applying the Uppsala method and HPLC analyses, respectively. The results showed that broccoli leaves had comparable levels of dietary fibre (26%-32% of dry weight (DW)) and phenolic compounds (6.3-15.2 mg/g DW) to many other food and vegetables considered valuable in the human diet from a health perspective. A significant positive correlation was found among soluble dietary fibre and phenolic acids indicating possible bindings between these components. Seasonal variations affected mainly the content of conjugated phenolics, and the content of insoluble dietary fibre. This study verified the importance of the use of broccoli production side streams (leaves) as they may contribute with health promoting components to the human diet and also socio-economic and environmental benefits to the bioeconomic development in the society.
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http://dx.doi.org/10.3390/ijerph17072406DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7178181PMC
April 2020

Dataset on multichannel connectivity and video transmission carried on commercial 3G/4G networks in southern Sweden.

Data Brief 2019 Aug 25;25:104192. Epub 2019 Jun 25.

Department of Clinical Sciences, Lund University, Sweden.

In this data article, we report real-world data on multichannel connectivity and videotransmission carried on commercial 3G/4G networks in the region of Skåne, southern Sweden. The data reported here complement the research article "Technical feasibility and ambulance nurses' view of a digital telemedicine system in pre-hospital stroke care - A pilot study" (1). The dataset was originally collected as part of a project aimed to test in a clinical setting the quality and usefulness of a linked image and sound transmission in the prehospital assessment of patients with suspected stroke. The project built on previous studies indicating that using high-quality telemedicine in stroke cases is feasible and has already impacted local stroke care Schwamm et al., 2009. In addition, studies support the hypothesis that stroke telemedicine consultations, compared with telephone-only, result in more accurate decision-making Demaerschalk et al., 2012. Cellular networks for 3/4G networks have been greatly improved, a prerequisite for the use of these networks for e. g. medical applications. However, connectivity maps for planning purposes are usually based on theoretical values that do not consider smaller features of the terrain such as large trees, hills, rocks etc. and that may interfere with connectivity. To leverage several networks, multichannel devices have been developed that split the original transmission onto several independent channels and recombine the transmission on the receiver side. This setup allows to increase the available bandwidth and introduces at the same time an element of redundancy, provided that several providers with independent networks are used.
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http://dx.doi.org/10.1016/j.dib.2019.104192DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6614084PMC
August 2019

Technical feasibility and ambulance nurses' view of a digital telemedicine system in pre-hospital stroke care - A pilot study.

Int Emerg Nurs 2019 05 30;44:35-40. Epub 2019 Apr 30.

Office of Medical Services, Department of Clinical Sciences, Lund University, Sweden; Office of Medical Service, Region Skåne, Sweden. Electronic address:

Background: High-quality telemedicine in cases of suspected stroke has comparable precision with on-site medical examinations. A novel technical concept was developed in order to deliver a video/audio system to achieve more efficient patient assessment and diagnostic support.

Aims And Objectives: The aim of the present pilot-study was to evaluate in a clinical setting the quality of a linked image and sound transmission in the prehospital assessment of patients with suspected stroke. In addition, we wanted to elucidate how ambulance nurses experienced the use of this innovative technology.

Design: The study used a quantitative method using questionnaires with fixed response options, combined with a qualitative approach to assess complementary statements of prehospital emergency care nurses (PEN) that had used the system.

Methods: The study was conducted in one ambulance care office and one hospital in southern Sweden. Six PEN and one neurological specialist (Dr) expressed their perceptions based on 11 cases with suspected stroke. Responses were assessed in the dimensions of the technology (Dr - image quality/sound quality; Dr and PEN), safety, sense of increased control and uniform assessment. A questionnaire technique was used, complemented with a qualitative part of the content analysis (PEN views).

Results: In the technology dimension, the Dr evaluated the image quality as Very good to Good (100%) while 75% of PEN answered that the digital stroke concept felt reliable to use and the digital stroke assessment is believed to increase uniform assessment. Asked if the present digital concept should be further developed and if further digital systems should be developed in general, the PEN were split in their responses (50 vs 50%), which could be related to a conception of unclear efficacy of the concept. Descriptions of the decisive comments emerged in three categories; Minor operating interference, Physician's competence crucial and Unclear efficacy.

Conclusion: All respondents seem to have confidence in the assessed digital stroke concept. The image quality is perceived suitable in the assessment situation but the nurses expressed ambiguity about the efficiency of the entire concept. The ambulance nurses also highlighted the physician's skills and personality as important factors for further development of the concept.
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http://dx.doi.org/10.1016/j.ienj.2019.03.008DOI Listing
May 2019

Appetite and Subsequent Food Intake Were Unaffected by the Amount of Sourdough and Rye in Soft Bread-A Randomized Cross-Over Breakfast Study.

Nutrients 2018 Oct 30;10(11). Epub 2018 Oct 30.

Department of Biology and Biological Engineering, Food and Nutrition Science, Chalmers University of Technology, 412 96 Gothenburg, Sweden.

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 no differences between the test breads. The content of rye in the test breads differed within a narrow range, which might explain the lack of a consistent effect of rye on appetite. Microstructural examination of the test breads showed an increased aggregation of proteins in the breads with high content of sourdough, indicating additional changes to the breads, beyond change in pH, which may counteract the potential effect of decreased pH in the bread on appetite. In conclusion, our study does not support an effect of sourdough on appetite and ad libitum food intake.
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http://dx.doi.org/10.3390/nu10111594DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6266039PMC
October 2018

Resistant starch and other dietary fiber components in tubers from a high-amylose potato.

Food Chem 2018 Jun 3;251:58-63. Epub 2018 Jan 3.

Department of Molecular Sciences, Swedish University of Agricultural Sciences, Box 7015, SE-750 07 Uppsala, Sweden. Electronic address:

Tubers from a genetically modified high-amylose line T-2012 and its parental potato cultivar Dinamo were analyzed for resistant starch (RS) and dietary fiber (DF) after cooking and cold storage. For uncooked potatoes, the high-amylose tubers (30% of dry matter, DM) had much lower RS than the parent tubers (56% of DM). However, after cooking, the high-amylose tubers gave more RS (13% of DM) than the parent (4% of DM), and the RS level increased further to about 20% of DM after 1 day of cold storage. The altered RS content was attributable to changes in amylose content, starch granule structure, and amylopectin structure induced by the genetic modification. The high-amylose tubers also contained more DF (10-14% of DM) than the parent (5-7% of DM). Furthermore, cell wall composition was indirectly affected by the genetic modification, giving more cellulose and less pectin in the high-amylose tubers than the parent.
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http://dx.doi.org/10.1016/j.foodchem.2018.01.028DOI Listing
June 2018

A Dual-Promoter Gene Orchestrates the Sucrose-Coordinated Synthesis of Starch and Fructan in Barley.

Mol Plant 2017 12 7;10(12):1556-1570. Epub 2017 Nov 7.

Department of Plant Biology, Uppsala BioCenter, Linnean Centre for Plant Biology, Swedish University of Agricultural Sciences, P.O. Box 7080, 75007 Uppsala, Sweden. Electronic address:

Sequential carbohydrate synthesis is important for plant survival because it guarantees energy supplies for growth and development during plant ontogeny and reproduction. Starch and fructan are two important carbohydrates in many flowering plants and in human diets. Understanding this coordinated starch and fructan synthesis and unraveling how plants allocate photosynthates and prioritize different carbohydrate synthesis for survival could lead to improvements to cereals in agriculture for the purposes of greater food security and production quality. Here, we report a system from a single gene in barley employing two alternative promoters, one intronic/exonic, to generate two sequence-overlapping but functionally opposing transcription factors, in sensing sucrose, potentially via sucrose/glucose/fructose/trehalose 6-phosphate signaling. The system employs an autoregulatory mechanism in perceiving a sucrose-controlled trans activity on one promoter and orchestrating the coordinated starch and fructan synthesis by competitive transcription factor binding on the other promoter. As a case in point for the physiological roles of the system, we have demonstrated that this multitasking system can be exploited in breeding barley with tailored amounts of fructan to produce healthy food ingredients. The identification of an intron/exon-spanning promoter in a hosting gene, resulting in proteins with distinct functions, adds to the complexity of plant genomes.
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http://dx.doi.org/10.1016/j.molp.2017.10.013DOI Listing
December 2017

Combined Magnetomotive ultrasound, PET/CT, and MR imaging of Ga-labelled superparamagnetic iron oxide nanoparticles in rat sentinel lymph nodes in vivo.

Sci Rep 2017 07 6;7(1):4824. Epub 2017 Jul 6.

Medical Services, Skåne University Hospital, Lund, Sweden.

Current methods for intra-surgical guidance to localize metastases at cancer surgery are based on radioactive tracers that cause logistical challenges. We propose the use of a novel ultrasound-based method, magnetomotive ultrasound (MMUS) imaging that employ a nanoparticle-based contrast agent that also may be used for pre-operative PET/MRI imaging. Since MMUS is radiation free, this eliminates the dependence between pre- and intra-operative imaging and the radiation exposure for the surgical staff. This study investigates a hypothetical clinical scenario of pre-operative PET imaging, combined with intra-operative MMUS imaging, implemented in a sentinel lymph node (SLN) rat model. At one-hour post injection of Ga-labelled magnetic nanoparticles, six animals were imaged with combined PET/CT. After two or four days, the same animals were imaged with MMUS. In addition, ex-vivo MRI was used to evaluate the amount of nanoparticles in each single SLN. All SLNs were detectable by PET. Four out of six SLNs could be detected with MMUS, and for these MMUS and MRI measurements were in close agreement. The MRI measurements revealed that the two SLNs undetectable with MMUS contained the lowest nanoparticle concentrations. This study shows that MMUS can complement standard pre-operative imaging by providing bedside real-time images with high spatial resolution.
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http://dx.doi.org/10.1038/s41598-017-04396-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5500498PMC
July 2017

Effects of variety and steeping conditions on some barley components associated with colonic health.

J Sci Food Agric 2016 Nov 18;96(14):4821-4827. Epub 2016 Aug 18.

Food and Nutrition Science, Biology and Biological Engineering, Chalmers University of Technology, SE-412 96, Göteborg, Sweden.

Background: Butyric acid is produced by degradation of dietary fibre by microbiota and is crucial for maintaining a healthy colon. The physicochemical properties are important for butyric acid formation, and this study aimed to evaluate the use of malting to tailor the functional characteristics of barley dietary fibre. The effect of different steeping conditions was evaluated in laboratory-scale malting experiments with three different barley varieties.

Results: Steeping at 35°C and with 0.4 % (v/v) lactic acid resulted in a higher content of β-glucan and soluble fibre in malts than in those steeped at lower temperature and lower lactic acid concentration. Resistant starch increased, whereas the content of soluble arabinoxylan was lower. Dietary fibre components in Tipple were more affected by steeping conditions than the other varieties. The total contents of iron, phytate and amylose were little influenced by steeping conditions.

Conclusion: The selection of steeping conditions during malting influences composition and the characteristics of dietary fibre in barley. However, the choice of barley variety is also important for tailoring of functional ingredients beneficial for colonic health. © 2016 The Authors. Journal of the Science of Food and Agriculture published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry.
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http://dx.doi.org/10.1002/jsfa.7923DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5129454PMC
November 2016

Starch structure in developing barley endosperm.

Int J Biol Macromol 2015 Nov 8;81:730-5. Epub 2015 Sep 8.

Department of Food Science, Swedish University of Agricultural Sciences, P.O. Box 7051, S-750 07 Uppsala, Sweden. Electronic address:

Barley spikes of the cultivars/breeding lines Gustav, Karmosé and SLU 7 were harvested at 9, 12 and 24 days after flowering in order to study starch structure in developing barley endosperm. Kernel dry weight, starch content and amylose content increased during development. Structural analysis was performed on whole starch and included the chain-length distribution of the whole starches and their β-limit dextrins. Karmosé, possessing the amo1 mutation, had higher amylose content and a lower proportion of long chains (DP ≥38) in the amylopectin component than SLU 7 and Gustav. Structural differences during endosperm development were seen as a decrease in molar proportion of chains of DP 22-37 in whole starch. In β-limit dextrins, the proportion of Bfp-chains (DP 4-7) increased and the proportion of BSmajor-chains (DP 15-27) decreased during development, suggesting more frequent activity of starch branching enzymes at later stages of maturation, resulting in amylopectin with denser structure.
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http://dx.doi.org/10.1016/j.ijbiomac.2015.09.013DOI Listing
November 2015

Thermal properties of barley starch and its relation to starch characteristics.

Int J Biol Macromol 2015 Nov 2;81:692-700. Epub 2015 Sep 2.

Department of Food Science, Swedish University of Agricultural Sciences, P.O. Box 7051, S-750 07 Uppsala, Sweden. Electronic address:

Amylopectin fine structure and starch gelatinization and retrogradation were studied in 10 different barley cultivars/breeding lines. Clusters and building blocks were isolated from the amylopectin by α-amylase from Bacillus amyloliquefaciens and their structure was characterized. Gelatinization was studied at a starch:water ratio of 1:3, and retrogradation was studied on gelatinized starch at starch:water ratio of 1:2, by differential scanning calorimetry. Three barley cultivars/breeding lines possessed the amo1 mutation, and they all had a lower molar proportion of chains of DP ≥38 and more of large building blocks. The amo1 mutation also resulted in a higher gelatinization temperature and a broader temperature interval during gelatinization. Overall, small clusters with a dense structure resulted in a higher gelatinization temperature while retrogradation was promoted by short chains in the amylopectin and many large building blocks.
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http://dx.doi.org/10.1016/j.ijbiomac.2015.08.068DOI Listing
November 2015

Barley malt increases hindgut and portal butyric acid, modulates gene expression of gut tight junction proteins and Toll-like receptors in rats fed high-fat diets, but high advanced glycation end-products partially attenuate the effects.

Food Funct 2015 Sep;6(9):3165-76

Food for Health Science Center, Kemicentrum, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.

Barley malt, a product of controlled germination, has been shown to produce high levels of butyric acid in the cecum and portal serum of rats and may therefore have anti-inflammatory effects. The aim of the study was to investigate how four barley malts, caramelized and colored malts, 50-malt and 350-malt, differing in functional characteristics concerning beta-glucan content and color, affect short-chain fatty acids (SCFA), barrier function and inflammation in the hindgut of rats fed high-fat diets. Male Wistar rats were given malt-supplemented high-fat diets for four weeks. Low and high-fat diets containing microcrystalline cellulose were incorporated as controls. All diets contained 70 g kg(-1) dietary fiber. The malt-fed groups were found to have had induced higher amounts of butyric and propionic acids in the hindgut and portal serum compared with controls, while cecal succinic acid only increased to a small extent. Fat increased the mRNA expression of tight junction proteins and Toll-like receptors (TLR) in the small intestine and distal colon of the rats, as well as the concentration of some amino acids in the portal plasma, but malt seemed to counteract these adverse effects to some extent. However, the high content of advanced glycation end-products (AGE) in caramelized malt tended to prohibit the positive effects on occludin in the small intestine and plasma amino acids seen with the other malt products. In conclusion, malting seems to be an interesting process for producing foods with positive health effects, but part of these effects may be destroyed if the malt contains a high content of AGE.
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http://dx.doi.org/10.1039/c5fo00150aDOI Listing
September 2015

Improved material properties of solution-cast starch films: Effect of varying amylopectin structure and amylose content of starch from genetically modified potatoes.

Carbohydr Polym 2015 Oct 19;130:388-97. Epub 2015 May 19.

Department of Food Science, Swedish University of Agricultural Sciences, Box 7051, SE-750 07 Uppsala, Sweden.

High-amylose potato starches were produced through genetic modification resulting in changed granule morphology and composition, with higher amylose content and increased chain length of amylopectin. The increased amylose content and structural changes in amylopectin enhanced film-forming behavior and improved barrier and tensile properties in starch films. The molecular structure in these starches was related to film-forming properties. Solution-cast films of high-amylose starch revealed a homogeneous structure with increasing surface roughness at higher amylose content, possibly due to amylose aggregation. Films exhibited significantly higher stress and strain at break compared with films of wild-type starch, which could be attributable to the longer chains of amylopectin being involved in the interconnected network and more interaction between chains, as shown using transmission electron microscopy. The oxygen permeability of high-amylose starch films was significantly decreased compared with wild-type starch. The nature of the modified starches makes them an interesting candidate for replacement of non-renewable oxygen and grease barrier polymers used today.
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http://dx.doi.org/10.1016/j.carbpol.2015.05.024DOI Listing
October 2015

Inter-laboratory evaluation of SEC-post-column calcofluor for determination of the weight-average molar mass of cereal β-glucan.

Carbohydr Polym 2015 Jun 21;124:254-64. Epub 2015 Feb 21.

Nofima, Norwegian Institute for Food, Fisheries and Aquaculture Research, PB 210, N-1431 Ås, Norway. Electronic address:

Even though size exclusion chromatography (SEC) with post column addition of calcofluor (SEC-calcofluor) has been used for the determination of cereal β-glucan molar mass in foods for many years, there is a lack of systematic evaluation of the method. To address this issue a set of suitable β-glucan standards were generated by preparative SEC and their molar mass characteristics were determined by analytical multi-detection SEC (refractive index (RI), light scattering). Each standard was then analysed by SEC-calcofluor at three different labs. As a direct comparison, the analyses were repeated with a RI detector. For SEC-calcofluor accurate measurements of weight average molar mass (Mw) can be made for β-glucan populations within 10-500×10(3)g/mol. Above this molar mass threshold there is an increasing tendency for underestimation of Mw. Precipitation of some β-glucan-calcofluor complexes may have delayed their transport into the detector.
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http://dx.doi.org/10.1016/j.carbpol.2015.02.019DOI Listing
June 2015

The effect of pH on hydrolysis, cross-linking and barrier properties of starch barriers containing citric acid.

Carbohydr Polym 2013 Nov 26;98(2):1505-13. Epub 2013 Jul 26.

Department of Engineering and Chemical Sciences, Karlstad University, SE-65188 Karlstad, Sweden. Electronic address:

Citric acid cross-linking of starch for e.g. food packaging applications has been intensely studied during the last decade as a method of producing water-insensitive renewable barrier coatings. We managed to improve a starch formulation containing citric acid as cross-linking agent for industrial paper coating applications by adjusting the pH of the starch solution. The described starch formulations exhibited both cross-linking of starch by citric acid as well as satisfactory barrier properties, e.g. fairly low OTR values at 50% RH that are comparable with EVOH. Furthermore, it has been shown that barrier properties of coated papers with different solution pH were correlated to molecular changes in starch showing both hydrolysis and cross-linking of starch molecules in the presence of citric acid. Hydrolysis was shown to be almost completely hindered at solution pH≥4 at curing temperatures≤105 °C and at pH≥5 at curing temperatures≤150 °C, whereas cross-linking still occurred to some extent at pH≤6.5 and drying temperatures as low as 70 °C. Coated papers showed a minimum in water vapor transmission rate at pH 4 of the starch coating solution, corresponding to the point where hydrolysis was effectively hindered but where a significant degree of cross-linking still occurred.
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http://dx.doi.org/10.1016/j.carbpol.2013.07.040DOI Listing
November 2013

Molecular structure of citric acid cross-linked starch films.

Carbohydr Polym 2013 Jul 21;96(1):270-6. Epub 2013 Mar 21.

Department of Food Science, Uppsala BioCenter, Swedish University of Agricultural Sciences, Box 7051, SE-75007 Uppsala, Sweden.

The effect of citric acid (CA) on starch films has been examined. A new method to detect cross-linking of starch by CA in solution-cast films by molecular weight measurements is described. Furthermore, we managed to distinguished between free, mono- and di-esterified CA and quantify di-ester content within starch films by using a modification in the method of complexometric titration with copper(II)-sulfate. Cross-linking of starch by CA occurred at low temperature, 70°C, which we assumed is so far the lowest temperature reported where cross-linking reaction occurred. This is essential for starch coating applications within paper industry since no high temperatures for curing will be required. However, curing at 150°C and high CA concentrations, 30 pph, increased cross-linking reaction. Furthermore, the physical properties like water solubility, gel content and glass transition temperature, were highly reflected by changes in the molecular structure i.e. cross-linking and hydrolysis, as well as CA content and curing temperature.
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http://dx.doi.org/10.1016/j.carbpol.2013.03.044DOI Listing
July 2013

On the interconnection of clusters and building blocks in barley amylopectin.

Int J Biol Macromol 2013 Apr 24;55:75-82. Epub 2012 Dec 24.

Department of Food Science, Swedish University of Agricultural Sciences, PO Box 7051, S-750 07 Uppsala, Sweden.

Amylopectin is a highly branched starch component built up of a large number of clustered α-D-glucose chains. A single C-chain possesses the reducing end and carries the rest of the macromolecule. The aim of this study was to investigate the interconnection of clusters and domains (groups of clusters) in barley amylopectin by isolation of the units with α-amylolysis and subsequent labelling of the C-chain in the φ,β-limit dextrins of these structural units with the fluorescent compound 2-aminopyridine. Because these C-chains were formed by α-amylolysis of B-chains in amylopectin, they were designated bc-chains to be distinguished from C-chains in amylopectin. Four barley samples were selected for the study, of which two had the amo1 genetic background. Longer bc-chains were found in domains suggesting their role in cluster interconnection. The average chain length of bc-chains was longer than the average chain length of B-chains and the size-distribution of the bc-chains was unimodal implying that the bc-chains comprise a unique category of chains. Extensive α-amylolysis of labelled amylopectin and clusters revealed the distribution of branched building blocks situated at the reducing end of these molecules. Any type of size group of building blocks can be situated at the reducing end, because the size-distribution of these blocks was similar to the distribution of all building blocks present in the sample. This suggested certain randomness in the distribution of the types of building blocks within the amylopectin macromolecule.
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http://dx.doi.org/10.1016/j.ijbiomac.2012.12.032DOI Listing
April 2013

Soluble β-1,3/1,6-glucan in seaweed from the southern hemisphere and its immunomodulatory effect.

Carbohydr Polym 2013 Jan 4;92(1):241-8. Epub 2012 Oct 4.

Facultad Tecnológica, Universidad de Santiago de Chile, Av. Libertador Bernardo, O'Higgins, 3363 Estación Central, Santiago, Chile.

Five types of macroalgae from the southern hemisphere were analysed for the presence of β-1,3/1,6-glucan and its immunostimulant properties. We were able to extract soluble β-1,3/1,6-D-glucan from Durvillaea antarctica (Chamisso) Hariot (DA). The morphology of the brown algae influenced extraction, and the highest percentage of β-glucan was found in the fronds. The content of β-glucan in the stipes and holdfast was on average 33% and <5%, respectively, of that in the fronds. A simple laboratory extraction process was developed. A highly pure water-soluble polysaccharide, mainly composed of glucose residues, was obtained with a dominant average molecular weight of 6.9 kDa. NMR spectroscopy confirmed the polysaccharide structure to be of β-1,3/1,6-glucan type, comprising a β-1,3-glucan backbone and 21% degree of branching of β-1,6-glucan side chains. Mouse cells were exposed to four DA extract concentrations in water (50, 100, 250 and 500 μg/mL) and no adverse effects on survival were noted. Remarkably, the β-glucan induced a 16.9% increase in activated CD19+ B lymphocytes compared with the control sample. The optimal concentration for maximum activity was 100 μg DA extract/mL.
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http://dx.doi.org/10.1016/j.carbpol.2012.09.071DOI Listing
January 2013

Molecular insights into how a deficiency of amylose affects carbon allocation--carbohydrate and oil analyses and gene expression profiling in the seeds of a rice waxy mutant.

BMC Plant Biol 2012 Dec 5;12:230. Epub 2012 Dec 5.

College of Life Science, China JiLiang University, Hangzhou 310018, China.

Background: Understanding carbon partitioning in cereal seeds is of critical importance to develop cereal crops with enhanced starch yields for food security and for producing specified end-products high in amylose, β-glucan, or fructan, such as functional foods or oils for biofuel applications. Waxy mutants of cereals have a high content of amylopectin and have been well characterized. However, the allocation of carbon to other components, such as β-glucan and oils, and the regulation of the altered carbon distribution to amylopectin in a waxy mutant are poorly understood. In this study, we used a rice mutant, GM077, with a low content of amylose to gain molecular insight into how a deficiency of amylose affects carbon allocation to other end products and to amylopectin. We used carbohydrate analysis, subtractive cDNA libraries, and qPCR to identify candidate genes potentially responsible for the changes in carbon allocation in GM077 seeds.

Results: Carbohydrate analysis indicated that the content of amylose in GM077 seeds was significantly reduced, while that of amylopectin significantly rose as compared to the wild type BP034. The content of glucose, sucrose, total starch, cell-wall polysaccharides and oil were only slightly affected in the mutant as compared to the wild type. Suppression subtractive hybridization (SSH) experiments generated 116 unigenes in the mutant on the wild-type background. Among the 116 unigenes, three, AGP, ISA1 and SUSIBA2-like, were found to be directly involved in amylopectin synthesis, indicating their possible roles in redirecting carbon flux from amylose to amylopectin. A bioinformatics analysis of the putative SUSIBA2-like binding elements in the promoter regions of the upregulated genes indicated that the SUSIBA2-like transcription factor may be instrumental in promoting the carbon reallocation from amylose to amylopectin.

Conclusion: Analyses of carbohydrate and oil fractions and gene expression profiling on a global scale in the rice waxy mutant GM077 revealed several candidate genes implicated in the carbon reallocation response to an amylose deficiency, including genes encoding AGPase and SUSIBA2-like. We believe that AGP and SUSIBA2 are two promising targets for classical breeding and/or transgenic plant improvement to control the carbon flux between starch and other components in cereal seeds.
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http://dx.doi.org/10.1186/1471-2229-12-230DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3541260PMC
December 2012

Contents of dietary fibre components and their relation to associated bioactive components in whole grain wheat samples from the HEALTHGRAIN diversity screen.

Food Chem 2013 Feb 2;136(3-4):1243-8. Epub 2012 Oct 2.

Department of Food Science, Swedish University of Agricultural Sciences, P.O. Box 7051, SE-750 07 Uppsala, Sweden.

A large and diverse material collection of whole grain wheat samples (n=129) was analysed for total dietary fibre (TDF) content and composition, including fructan (11.5-15.5%). Correlations between the dietary fibre components, associated bioactive components (e.g. tocols, sterols, phenolic acids and folates) and agronomic properties previously determined on the same samples were found with multivariate analysis (PCA). Samples from the same countries had similar characteristics. The first PC described variation in components concentrated in the starchy endosperm (e.g. starch, β-glucan and fructan) and the dietary fibre components concentrated in the bran (e.g. TDF, arabinoxylan and cellulose). The second PC described the variation in kernel weight and other bran components such as alkylresorcinols, tocols and sterols. Interestingly, there was no correlation among these different groups of bran components, which reflected their concentration in different bran tissues. The results are of importance for plant breeders who wish to develop varieties with health-promoting effects.
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http://dx.doi.org/10.1016/j.foodchem.2012.09.074DOI Listing
February 2013

Digestibility of fibre sources and molecular weight distribution of fibre fractions in ileal digesta of growing pigs.

Arch Anim Nutr 2012 Dec;66(6):445-57

Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Uppsala, Sweden.

Seven post-valve T-caecum cannulated growing pigs were used in a change-over experiment with four diets and four 14-day periods to evaluate the total tract apparent digestibility (TTAD) and the ileal apparent digestibility (IAD) of diets with inclusion of chicory forage (CFO), sugar beet pulp (SBP), wheat bran (WB) and grass meal (GM), as well as the TTAD of the mentioned fibre sources. Moreover, this experiment evaluated the molecular weight distribution of soluble non-starch polysaccharide (NSP) fractions in diet and ileal digesta from pigs fed the CFO and SBP diets. The experimental diets were balanced to have similar NSP content and compromised of one part of the basal diet and one part of the four fibre sources (CFO, SBP, WB and GM). In addition, all pigs were fed the basal diet during a 14-day period before and after the experimental periods. Diet affected the TTAD of all dietary components except glucose. The TTAD of organic matter (OM) was higher for Diet SBP than for Diets WB and CFO, showing both were higher than Diet GM. The TTAD of NSP was higher for Diet SBP than Diets WB and GM. The IAD of OM was higher in Diet SBP than in the other diets. The IAD of NSP was lower in Diet WB than in the other diets. The TTAD of OM and energy of CFO was 0.43 ± 0.04 (standard error), which is similar to that reported for commonly used forage crops. The molecular weight distribution in ileal digesta showed different distributions between Diets CFO and SBP as well as between digesta from pigs fed these diets.
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http://dx.doi.org/10.1080/1745039X.2012.740309DOI Listing
December 2012

Alkylresorcinol metabolism in Swedish adults is affected by factors other than intake of whole-grain wheat and rye.

J Nutr 2012 Aug 27;142(8):1479-86. Epub 2012 Jun 27.

Department of Food Science, BioCenter, Swedish University of Agricultural Sciences, Uppsala, Sweden.

The urinary alkylresorcinol (AR) metabolites, 3,5-dihydroxybenzoic acid (DHBA) and 3-(3,5-dihydroxyphenyl)-propanoic acid (DHPPA), could potentially serve as biomarkers for intake of whole-grain (WG) wheat and rye. Excretion of AR metabolites is largely dependent on the intake of AR but may also be influenced by other factors. This study aimed to investigate the validity of free and conjugated AR metabolites as biomarkers for WG intake of wheat and rye and to identify potential determinants of AR metabolites in urine. We quantified free aglycones and conjugates of AR metabolites in 24-h urine collections from 52 free-living Swedish adults and calculated correlation coefficients between urinary AR metabolite excretion and self-reported WG intake. We used partial least-squares regression to identify possible determinants of urinary AR metabolites. Approximately 50% of urinary AR metabolites were found as conjugates. Excretions of individually quantified free and conjugated AR metabolites and their sums were correlated to self-reported intake of WG rye and wheat (r = 0.50-0.68; P < 0.001). Excretion of urinary AR metabolites was mainly dependent on intake of 2 major dietary AR homologs, C19:0 and C21:0. Sex, BMI, and vitamin C intake were identified as determinants of the proportion of free and glucuronidated DHPPA in the present study. Urinary AR metabolites may be useful in reflecting short-term to medium-term intake of WG, but urine samples should be deconjugated prior to quantification. Anthropometric and dietary factors affecting the proportion of conjugated AR metabolites in urine may to some extent influence AR elimination and thereby the performance of urinary AR metabolites as biomarkers.
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http://dx.doi.org/10.3945/jn.112.159244DOI Listing
August 2012

Varying quality of fish oil capsules: fatty acids and tocopherol.

Neuro Endocrinol Lett 2011 ;32 Suppl 2:37-40

Department of Food Science, Swedish University of Agricultural Sciences, Uppsala, Sweden.

Objectives: To assess the content and composition of fatty acids and tocopherols in commercially available oil capsules, and to assay thiobarbituric acid reactive substances (TBARS) as a marker of oxidation in these oils.

Methods: Fish and seal oil capsules were analyzed for their contents of long-chain omega-3 fatty acids (DPA, EPA, and DHA), tocopherols, and malondialdehyde.

Results: Large variations were found in the levels of EPA (6.5-40.9%), and DHA (8.1-26.4%), α-tocopherol (117-10282 μg/g), γ-tocopherol (406-2352 μg/g) and δ-tocopherol (127-978 μg/g). The level of malondialdehyde was very low in all capsules.

Conclusion: The tested samples of oil capsules showed large variation in quality with respect to long-chain n-3 polyunsaturated fatty acids and tocopherols. The low levels of malondialdehyde indicated a successful oxidation protection strategy.
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June 2012

Whole grain rye breakfast - sustained satiety during three weeks of regular consumption.

Physiol Behav 2012 Feb 28;105(3):877-84. Epub 2011 Oct 28.

Department of Food Science, Swedish University of Agricultural Sciences, P.O. Box 7051, SE-750 07 Uppsala, Sweden.

Whole grain rye products have previously been shown to increase feelings of satiety for up to 8h after intake under standardized conditions. This study was set out to investigate the sustainability of the satiating effect after regular consumption of breakfast meals with whole grain rye porridge or refined wheat bread. The study was randomized, cross-over and double-blind. Healthy subjects (n=24) were randomly assigned to daily consumption of iso-caloric standardized breakfast meals with whole grain rye porridge or refined wheat bread for two 3-wk phases, separated by a wash out of 3-4weeks. Each intervention phase had 3 scheduled visit days (days 1, 8 and 22) when appetite ratings (hunger, satiety and desire to eat) were registered for 24h at standardized conditions. Orocecal transit time (salicylazosulfapyridine/sulfapyridine method) and breath hydrogen as an indicator of colonic fermentation were measured at day 8 of each 3-wk phase in a subgroup (n=16). To investigate effects of breakfast on free-living food intake, 3-day weighed food diaries were self-registered during both intervention phases. Whole grain rye porridge breakfast resulted in higher ratings of satiety and lower hunger and desire to eat during 4h post consumption compared to refined wheat bread breakfast (p<0.001). This effect was sustained throughout the 3-wk study phases. Unlike previous studies, the effects did not persist into the afternoon (4-8h). The orocecal transit times after consumption of both breakfasts were similar and in the range of 5-6h. The rye porridge resulted in high levels of breath hydrogen 4-8h after intake, showing extensive colonic fermentation. This was however not related to any changes in appetite during this time-period. There were no significant differences in self-reported macronutrient- and energy intake between diets. This study shows that the satiating effect of rye persists after repeated daily consumption for up to three weeks. Clinicaltrials.gov Identifier: NCT01117363.
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http://dx.doi.org/10.1016/j.physbeh.2011.10.023DOI Listing
February 2012

A water-soluble fraction from a by-product of wheat increases the formation of propionic acid in rats compared with diets based on other by-product fractions and oligofructose.

Food Nutr Res 2011 17;55. Epub 2011 Oct 17.

Department of Food Technology, Engineering and Nutrition, Applied Nutrition and Food Chemistry, Lund University, Lund, Sweden.

Background: Dietary fibre is fermented by the colonic microbiota to carboxylic acids (CA), with potential health effects associated in particular with butyric and propionic acid.

Objective: To investigate the formation of CA in the hindgut of healthy rats fed dietary fibre from different fractions of wheat shorts, a by-product of the milling of wheat.

Design: Rats were fed dietary fibre (80 g/kg feed per day for 7 days) from wheat shorts and fractions thereof (ethanol-soluble, water-soluble and insoluble fractions), oligofructose (OF) diet and a mixture of oligofructose and raffinose (OR) diet.

Results: The water-soluble fraction, with a high content of arabinoxylan (AX), increased the formation of propionic acid in the hindgut and lowered the ratio of acetic to propionic acid in the portal blood of rats. High levels and proportions of butyric acid were seen in rats fed the OR diet. The pattern of CA resulting from the ethanol-soluble diet, mainly composed of fructan and raffinose, was more similar to that of the OF diet than the OR diet.

Conclusions: The high formation of propionic acid with the water-soluble fraction may be attributed to the high AX content. The results also indicate that the wheat fructans produced more propionic acid and less butyric acid than OF. It may furthermore be speculated that the formation of butyric acid associated with the OR diet was due to a synergetic effect of OR.
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http://dx.doi.org/10.3402/fnr.v55i0.6397DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3198505PMC
November 2011

The building block structure of barley amylopectin.

Int J Biol Macromol 2011 Dec 10;49(5):900-9. Epub 2011 Aug 10.

Department of Food Science, Swedish University of Agricultural Sciences, PO Box 7051, SE-750 07 Uppsala, Sweden.

Amylopectin branchpoints are present in amorphous lamellae of starch granules and organised into densely branched areas, referred to as building blocks. One single amylopectin cluster contains several building blocks. This study investigated the building block structure of domains (groups of clusters) and clusters in four different barley genotypes. Two of the barleys possessed the amo1 mutation, Glacier Ac38 and the double recessive SW 49427 with both wax and amo1 mutations, and were compared with the two waxy type barleys Cinnamon and Cindy. A previous detailed study on these four barley genotypes showed that the amo1 mutation affected the internal structure of amylopectin as manifested in the composition of clusters. In this work the building blocks were isolated from domains and clusters by extensive treatment with liquefying α-amylase of Bacillus subtilis and structurally characterised with enzymatic and chromatographic techniques. The proportion of large building blocks with a high number of chains was increased in the amo1 barleys, and the chain length between the blocks was short, which explained the previous findings of large clusters with more dense structure in the amo1 amylopectins.
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http://dx.doi.org/10.1016/j.ijbiomac.2011.08.001DOI Listing
December 2011

The cluster structure of barley amylopectins of different genetic backgrounds.

Int J Biol Macromol 2011 Nov 17;49(4):441-53. Epub 2011 Jun 17.

Department of Food Science, Swedish University of Agricultural Sciences, Uppsala, Sweden.

The unit chains of amylopectin are organized into clusters. In this study, the cluster structure was analysed in detail in four different genotypes of barley, of which two possessed the amo1 genetic background. Amylose content of the barley starches differed from 0 to 32.6%. Isolated amylopectin was hydrolysed with α-amylase from Bacillus subtilis into domains, defined as groups of clusters, which were size-fractionated by methanol. The domain fractions were further treated with α-amylase to release single clusters. Amylopectin, domains and clusters were subsequently treated with phosphorylase and β-amylase to produce φ,β-limit dextrins and the detailed internal structures of these different structure levels were investigated. Analysis was performed with gel-permeation and anion-exchange chromatography. Equal amount of A-chains were detected in all barleys, but the distribution of B-chains differed. At least two types of domain structures were identified in all four barley varieties. Large domains were built up by large clusters and small domains by small clusters. In all four barley samples the number of long chains was small suggesting that shorter chains with a degree of polymerization of 25-35 also are involved in the interconnection of clusters. The cluster structure of the amylopectin correlated with the genetic background. The two barley samples with amo1 genetic background possessed a more dense structure. Internal chain lengths in these two barleys were shorter resulting in larger domains built up by larger clusters.
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http://dx.doi.org/10.1016/j.ijbiomac.2011.04.014DOI Listing
November 2011

How does the preparation of rye porridge affect molecular weight distribution of extractable dietary fibers?

Int J Mol Sci 2011 24;12(5):3381-93. Epub 2011 May 24.

Department of Food Science, Swedish University of Agricultural Sciences, Box, 7051, S-75007 Uppsala, Sweden; E-Mails: (P.A.); (R.A.).

Extractable dietary fiber (DF) plays an important role in nutrition. This study on porridge making with whole grain rye investigated the effect of rest time of flour slurries at room temperature before cooking and amount of flour and salt in the recipe on the content of DF components and molecular weight distribution of extractable fructan, mixed linkage (1→3)(1→4)-β-d-glucan (β-glucan) and arabinoxylan (AX) in the porridge. The content of total DF was increased (from about 20% to 23% of dry matter) during porridge making due to formation of insoluble resistant starch. A small but significant increase in the extractability of β-glucan (P = 0.016) and AX (P = 0.002) due to rest time was also noted. The molecular weight of extractable fructan and AX remained stable during porridge making. However, incubation of the rye flour slurries at increased temperature resulted in a significant decrease in extractable AX molecular weight. The molecular weight of extractable β-glucan decreased greatly during a rest time before cooking, most likely by the action of endogenous enzymes. The amount of salt and flour used in the recipe had small but significant effects on the molecular weight of β-glucan. These results show that whole grain rye porridge made without a rest time before cooking contains extractable DF components maintaining high molecular weights. High molecular weight is most likely of nutritional importance.
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http://dx.doi.org/10.3390/ijms12053381DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3116197PMC
January 2015
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