| 1. |
- Andersson, Johanna, et al.
(författare)
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Comparison of steaming and boiling of root vegetables for enhancing carbohydrate content and sensory profile
- 2022
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Ingår i: Journal of Food Engineering. - : Elsevier BV. - 0260-8774 .- 1873-5770. ; 312
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Tidskriftsartikel (refereegranskat)abstract
- Root vegetables have unique techno-functional and nutritional properties however, their use in processed foods is limited to a few species, partially due to a lack of knowledge related to the impact of thermal treatments on the sensory properties. This study investigated the effect of steaming and boiling on the microstructure, mechanical properties, and sensory profile of three model root vegetables with distinct carbohydrate composition: Jerusalem artichoke (Helianthus tuberosus L.), parsnip (Pastinaca sativa), and beetroot (Beta vulgaris). Thermally treated Jerusalem artichoke and parsnip showed higher content of cell wall polysaccharides, particularly β-glucans (e.g. cellulose) and pectic components, compared to raw. Steaming produced more cell shrinkage and loss of cell-cell adhesion than boiling, leading to softer vegetables. Processed beetroot showed loss of cell turgor and drastic softening but not clear changes in overall carbohydrate content. The scores for several flavour and in-mouth attributes were higher for steamed vegetables compared to boiled. Our results give insights on the processability of root vegetables towards products with enhanced sensory and nutritional properties.
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| 2. |
- Chiralt, A., et al.
(författare)
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Use of by-products in edible coatings and biodegradable packaging materials for food preservation
- 2020
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Ingår i: Sustainability of the Food System. - : Elsevier Inc.. ; , s. 101-127
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Bokkapitel (refereegranskat)abstract
- A large part of the by-products of plant and animal origin are sources of different valuable compounds, such as polysaccharides or proteins, which are useful materials for developing edible or biodegradable coatings and film formulations. Nowadays, this has acquired great importance in the development of new materials for substituting, at least partially, the traditional food packaging plastics, which show significant shortcomings in terms of their environmental impact. This also implies the use of renewable resources instead of the limited petroleum reserves.Alternative and novel materials, which possess commercial potential, are those derived from under-used food products, renewable resources and the valorisation of agro-industrial and marine wastes. The exploitation of these materials additionally provides added value to the waste products and represents an attractive alternative to the non-renewable sources, in the framework of circular economy. In addition, most of them are not just biodegradable, but are also edible, or can even be considered as active compounds (e.g. with antimicrobial or antioxidant properties), thereby contributing to the development of new sustainable packaging strategies for food preservation. In this chapter, these alternative materials are explored and the benefits and drawbacks are addressed.
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| 3. |
- Endt, Sebastian, et al.
(författare)
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In Vivo Myelin Water Quantification Using Diffusion–Relaxation Correlation MRI : A Comparison of 1D and 2D Methods
- 2023
-
Ingår i: Applied Magnetic Resonance. - 0937-9347. ; 54:11-12, s. 1571-1588
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Tidskriftsartikel (refereegranskat)abstract
- Multidimensional Magnetic Resonance Imaging (MRI) is a versatile tool for microstructure mapping. We use a diffusion weighted inversion recovery spin echo (DW-IR-SE) sequence with spiral readouts at ultra-strong gradients to acquire a rich diffusion–relaxation data set with sensitivity to myelin water. We reconstruct 1D and 2D spectra with a two-step convex optimization approach and investigate a variety of multidimensional MRI methods, including 1D multi-component relaxometry, 1D multi-component diffusometry, 2D relaxation correlation imaging, and 2D diffusion-relaxation correlation spectroscopic imaging (DR-CSI), in terms of their potential to quantify tissue microstructure, including the myelin water fraction (MWF). We observe a distinct spectral peak that we attribute to myelin water in multi-component T1 relaxometry, T1-T2 correlation, T1-D correlation, and T2-D correlation imaging. Due to lower achievable echo times compared to diffusometry, MWF maps from relaxometry have higher quality. Whilst 1D multi-component T1 data allows much faster myelin mapping, 2D approaches could offer unique insights into tissue microstructure and especially myelin diffusion.
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| 4. |
- Johansson, Mathias, et al.
(författare)
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Mixed legume systems of pea protein and unrefined lentil fraction: Textural properties and microstructure
- 2021
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Ingår i: LWT - Food Science and Technology. - : Elsevier BV. - 1096-1127 .- 0023-6438. ; 144
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Tidskriftsartikel (refereegranskat)abstract
- Within the context of circular economy, there is an increasing interest to utilise agrifood by-products. However, extensive extraction and purification steps make the valorisation of side streams not always cost effective. Therefore, an increased knowledge of the functionality of unrefined side streams could increase their utilisation in food products. We investigated the thermal gelation of mixed legume systems containing a commercial pea protein isolate (Pisum sativum) and the unrefined fraction remaining after protein extraction from lentils (Lens culinaris). The unrefined lentil fraction contained mainly starch (~45 g/100 g) and insoluble cell wall polysaccharides (~50 g/100 g) with minor amounts of soluble protein (4 g/100 g) and polyphenols (<1 mg GAE/g). The addition of the unrefined lentil fraction increased the strength and Young's modulus of pea protein gels in the pH range 3–4.2, and also increased the gels’ elastic modulus G'. The microstructure could be described as a mixed network of swollen protein particles of different sizes (5–50 μm), gelatinised starch and cell wall fragments. The results demonstrate that unrefined side streams from lentils could be used for textural modification of plant protein gels, with implications for the design of novel plant-based foods.
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| 5. |
- Kaushik, Sandeep S., et al.
(författare)
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Region of interest focused MRI to synthetic CT translation using regression and segmentation multi-task network
- 2023
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Ingår i: Physics in Medicine and Biology. - : Institute of Physics (IOP). - 0031-9155 .- 1361-6560. ; 68:19
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Tidskriftsartikel (refereegranskat)abstract
- Objective: In MR-only clinical workflow, replacing CT with MR image is of advantage for workflow efficiency and reduces radiation to the patient. An important step required to eliminate CT scan from the workflow is to generate the information provided by CT via an MR image. In this work, we aim to demonstrate a method to generate accurate synthetic CT (sCT) from an MR image to suit the radiation therapy (RT) treatment planning workflow. We show the feasibility of the method and make way for a broader clinical evaluation.Approach: We present a machine learning method for sCT generation from zero-echo-time (ZTE) MRI aimed at structural and quantitative accuracies of the image, with a particular focus on the accurate bone density value prediction. The misestimation of bone density in the radiation path could lead to unintended dose delivery to the target volume and results in suboptimal treatment outcome. We propose a loss function that favors a spatially sparse bone region in the image. We harness the ability of the multi-task network to produce correlated outputs as a framework to enable localization of region of interest (RoI) via segmentation, emphasize regression of values within RoI and still retain the overall accuracy via global regression. The network is optimized by a composite loss function that combines a dedicated loss from each task.Main results: We have included 54 brain patient images in this study and tested the sCT images against reference CT on a subset of 20 cases. A pilot dose evaluation was performed on 9 of the 20 test cases to demonstrate the viability of the generated sCT in RT planning. The average quantitative metrics produced by the proposed method over the test set were-(a) mean absolute error (MAE) of 70 ± 8.6 HU; (b) peak signal-to-noise ratio (PSNR) of 29.4 ± 2.8 dB; structural similarity metric (SSIM) of 0.95 ± 0.02; and (d) Dice coefficient of the body region of 0.984 ± 0.Significance: We demonstrate that the proposed method generates sCT images that resemble visual characteristics of a real CT image and has a quantitative accuracy that suits RT dose planning application. We compare the dose calculation from the proposed sCT and the real CT in a radiation therapy treatment planning setup and show that sCT based planning falls within 0.5% target dose error. The method presented here with an initial dose evaluation makes an encouraging precursor to a broader clinical evaluation of sCT based RT planning on different anatomical regions.
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| 6. |
- Koch, Kristine, et al.
(författare)
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Amylose and amylopectin molecular fractions and chain length distribution of amylopectin in 12 varieties of Ghanaian sweet potato (Ipomoea batatas) flours
- 2017
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Ingår i: International Journal of Food Properties. - : Informa UK Limited. - 1094-2912 .- 1532-2386. ; 20, s. 3225-3233
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Tidskriftsartikel (refereegranskat)abstract
- Sweet potato (Ipomoea batatas) is a commonly cultivated root crop in tropical and subtropical regions, including Ghana. Different varieties of sweet potato have been bred, in order to expand its utilisation within the food and industrial sector. This study analysed flours made from 12 recently developed Ghanaian sweet potato varieties in terms of their amylose and amylopectin molecular fractions and amylopectin chain length distribution. Starch content of the sweet potato flours ranged from 49 to 77 g/100 g dry matter, with 11 of the varieties containing above 60 g/100 g dry matter. An orange-fleshed variety, Apomuden, had the lowest amount of starch (48.9 g/100 g dry matter), while the cream-fleshed variety Histarch had the highest (77.3 g/100 g dry matter). The flours from the 12 sweet potato varieties had intermediate amounts of amylose, within the range 10-30 g/100 g dry matter, and showed typical molecular distribution according to size-exclusion chromatography (SEC). The fine structures of amylopectin, as revealed by anion-exchange chromatography, contained features common for starches of C-type X-ray pattern, but some structural differences were also observed.
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| 7. |
- Koch, Kristine, et al.
(författare)
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Physicochemical and functional properties of flour from twelve varieties of Ghanaian sweet potatoes
- 2017
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Ingår i: International Food Research Journal. - 1985-4668. ; 24, s. 2549-2556
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Tidskriftsartikel (refereegranskat)abstract
- Physicochemical and functional properties of flours produced from 12 varieties of sweet potatoes had colour indicating Apomuden (AP) as the darkest (L* values 83.6) and Ligri (GR) as the lightest (L* values 89.4) of the flours. The moisture content ranges from 7.6 to 10% below 15% specified for flours. Water activity was ranged from 0.5 to 0.6, an indication of shelf-stable flours. The varieties Faara (CFA) and Sauti (SAT), which had high amounts of moisture were also similar in their water activities. The pH of the flours ranged from 5.8 to 6.2, indicating low acidity. The flours indicated easy-to-cook properties as their pasting temperature was between 79 and 84 degrees C. Peak viscosity ranged between 75 and 304 RVU while setback viscosity ranged from 49 to 148RVU. AP had lower pasting properties but showed the least tendency to retrograde, with a setback ratio of 1.4. Ligri (GR) and Histarch (HI) showed the highest peak viscosity (304 and 300RVU) whereas flour from Bohye (BO) and Otoo (OT) were the most stable. The flours possess physicochemical and functional properties that makes them applicable in a wide array of food and industrial purposes. (c) All Rights Reserved
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| 8. |
- Menzel, Carolin, et al.
(författare)
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Alkylresorcinols in Swedish cereal food products
- 2012
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Ingår i: Journal of Food Composition and Analysis. - : Elsevier BV. - 0889-1575 .- 1096-0481. ; 28:2, s. 119-125
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Tidskriftsartikel (refereegranskat)abstract
- In this study alkylresorcinol (AR) content and homologue composition was determined in 159 cereal products commonly consumed in Sweden. Food items were sorted into seven groups including soft bread, crisp bread, breakfast cereals, pasta, flour, cookies and other cereal products with varying content of rye, wheat, oat, corn, rice and maize. The analyzed total AR content ranged from not detectable to 4178 μg/g (fresh weight). Bran and whole grain (WG) items showed highest AR contents and were comparable to previous reports. The AR content was strongly correlated with WG content from rye and wheat cereals (r = 0.80, P < 0.001), the main source of AR. In addition, the calculated ratio of the homologues C17:0 and C21:0, which was previously reported to distinguish between rye and wheat products, was associated to the proportion of rye content in WG of wheat and rye (r = 0.83, P < 0.001). The data from the present study can be used to estimate AR intake from WG of rye and wheat in the Swedish population and the results indicated that WG content from rye and wheat may be predicted by using AR content and homologue composition in cereal products.
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| 9. |
- Menzel, Carolin, et al.
(författare)
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Antioxidant starch films containing sunflower hull extracts
- 2019
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 214, s. 142-151
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Tidskriftsartikel (refereegranskat)abstract
- This study explores the preparation of antioxidant starch food packaging materials by the incorporation of valuable phenolic compounds extracted from sunflower hulls, which are an abundant by-product from food industry. The phenolic compounds were extracted with aqueous methanol and embedded into starch films. Their effect on starch films was investigated in terms of antioxidant activity, optical, thermal, mechanical, barrier properties and changes in starch molecular structure. The starch molecular structure was affected during thermal processing resulting in a decrease in molar mass, smaller amylopectin molecules and shorter amylose branches. Already 1-2% of extracts were sufficient to produce starch films with high antioxidant capacity. Higher amounts (4-6%) of extract showed the highest antioxidant activity, the lowest oxygen permeability and high stiffness and poor extensibility. The phenolic extracts affected predominantly the mechanical properties, whereas other changes could mainly be correlated to the lower glycerol content which was partially substituted by the extract.
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| 10. |
- Menzel, Carolin, et al.
(författare)
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Impact of the Coating Process on the Molecular Structure of Starch-Based Barrier Coatings
- 2014
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Ingår i: Journal of Applied Polymer Science. - : Wiley. - 0021-8995 .- 1097-4628. ; 131
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Tidskriftsartikel (refereegranskat)abstract
- Molecular analysis of starch structure can be used to explain and predict changes in physical properties, such as water vapor and oxygen barrier properties in packaging materials. Solution casting is a widely used technique to create films from starch formulations. This study compared the molecular properties of these standard films with those of experimental coatings applied to paper in laboratory-scale and pilot-scale trials, with all three techniques using the same starch formulation. The results revealed large differences in molecular structure, i.e., cross-linking and hydrolysis, between films and coatings. The main differences were due to the shorter drying time allowed to laboratory-scale coatings and the accelerated drying process in pilot trials owing to the high energy output of infrared dryers. Furthermore, surface morphology was highly affected by the coating technique used, with a rougher surface and many pinholes occurring in pilot-scale coatings, giving lower water vapor permeability than laboratory-scale coatings. (C) 2014 Wiley Periodicals, Inc.
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| 11. |
- Menzel, Carolin, et al.
(författare)
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Improved material properties of solution-cast starch films : Effect of varying amylopectin structure and amylose content of starch from genetically modified potatoes
- 2015
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 130, s. 388-397
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Tidskriftsartikel (refereegranskat)abstract
- 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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| 12. |
- Menzel, Carolin
(författare)
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Improvement of starch films for food packaging through a three-principle approach : Antioxidants, cross-linking and reinforcement
- 2020
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 250
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Tidskriftsartikel (refereegranskat)abstract
- This study uses sunflower hulls, a by-product from the sunflower snack industry, to recover both, valuable phenolic compounds and cellulose fibers, for the production of antioxidant reinforced starch films as potential food packaging material. The phenolic extract provided antioxidant properties to the films with EC50 values of 89 mg film/mg DPPH. The cellulose fibers reinforced the starch films with a threefold increase in Young's modulus. Furthermore, citric acid was added to induce cross-linking of the starch polymers and improve film integrity. The addition of citric acid induced both, starch polymer hydrolysis and cross-linking, seen in a shift in chain-length distribution after debranching with iso-amylase. This is the first study that focuses on a three-principle approach to improve edible starch films, and follows UN goals on sustainability to reduce waste and increase value in by-products as a step forward to functionalize packaging material.
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| 13. |
- Menzel, Carolin, et al.
(författare)
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Incorporation of natural antioxidants from rice straw into renewable starch films
- 2019
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Ingår i: International Journal of Biological Macromolecules. - : Elsevier B.V.. - 0141-8130 .- 1879-0003.
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Tidskriftsartikel (refereegranskat)abstract
- This study showed that rice straw waste is a valuable source for the extraction of water-soluble phenolic compounds that can be successfully incorporated into bioactive starch-based films. The major phenolic compounds in the extract were identified as ferulic, p-coumaric and protocatechuic acid using UHPLC-MS. Homogeneous films with antioxidant properties were produced by melt blending and compression molding and the changes in the physico-chemical properties were evaluated. The produced antioxidant starch films were slightly reddish-colored and exhibited good in-vitro antiradical scavenging activity against DPPH*. The addition of the antioxidant extract improved the oxygen barrier properties without negatively affecting the thermal and the water vapor barrier properties. However, antioxidant starch films turned more brittle with increasing amount of the antioxidant extract, which was probably due to interactions of phenolic compounds with the starch chains. The film forming process induced chain scission of starch molecules in all films, shown in a decrease in molecular weight of native starch from 9.1 × 106 Da to values as low as 1.0–3.5 × 106 Da. This study aids a circular economy by recycling rice straw for the production of bioactive food packaging.
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| 14. |
- Menzel, Carolin, et al.
(författare)
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Molecular structure of citric acid cross-linked starch films
- 2013
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Ingår i: Carbohydrate Polymers. - Amsterdam : Elsevier. - 0144-8617 .- 1879-1344. ; 96:2, s. 270-276
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Tidskriftsartikel (refereegranskat)abstract
- The effect of citric acid (CA) on starch films has been examined. A new method to detect cross-linkingof starch by CA in solution-cast films by molecular weight measurements is described. Furthermore, wemanaged to distinguished between free, mono- and di-esterified CA and quantify di-ester content withinstarch 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 lowesttemperature reported where cross-linking reaction occurred. This is essential for starch coating applica-tions within paper industry since no high temperatures for curing will be required. However, curing at150◦C and high CA concentrations, 30 pph, increased cross-linking reaction. Furthermore, the physicalproperties like water solubility, gel content and glass transition temperature, were highly reflected bychanges in the molecular structure i.e. cross-linking and hydrolysis, as well as CA content and curingtemperature.
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| 15. |
- Menzel, Carolin
(författare)
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Starch structures and their usefulness in the production of packaging materials
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Environmental concerns about increasing industrial use of plastics and the associated waste are raising the demand for renewable sources to replace petroleum-based products, especially in the packaging sector. This thesis examined the relationship between molecular structures of starch and their material properties in coating materials for food packaging. Chemical modification of starch with citric acid and tailored starches from genetically modified potatoes with higher amylose content was used to improve film formation, reduce water sensitivity and decrease gas permeation. Citric acid was used as a cross-linking agent and as a plasticiser to improve the barrier properties of starch-based barrier coatings. Methods to detect the cross-linking of starch by quantifying the di-ester content of citric acid and measuring molecular weight changes were developed. Starch films containing highest citric acid content showed the highest cross-linking density and lowest water solubility, but also showed the highest degree of starch degradation due to acid hydrolysis. Adjustment of pH in the starch formulation was used to control starch degradation and adapt it to industrial needs. At pH 4, hydrolysis of starch nearly stopped but cross-linking reaction still occurred, leading to minimum gas permeation. Cross-linking occurred already at temperatures as low as 70°C. Hence no curing step was needed to initiate cross-linking reaction. This is suitable for industrial paper coating applications since high temperature is not required. The coating process had a great impact on the molecular structure of starch. Laboratory-scale coatings showed a lower degree of cross-linking and no significant hydrolysis of starch compared with solution-cast films, a difference which could be attributable to shorter drying time in laboratory-scale coatings. The high evaporation rate in industrial pilot-scale coatings promoted cross-linking, but also increased coating surface unevenness, resulting in pinholes, which diminished barrier properties. Studies of tailored starches from genetically modified potatoes with expected increased amylose content showed irregular granules but no weakening of birefringence. It was found that altered amylopectin structure rather than high amylose content resulted in better barrier properties. The amylose-like structure formed in the cast films of starches from genetically modified potatoes decreased oxygen permeability and improved film strength.
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| 16. |
- Menzel, Carolin, et al.
(författare)
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Wheat starch carbamate: Production, molecular characterization, and film forming properties
- 2017
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617. ; 172, s. 365-373
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Tidskriftsartikel (refereegranskat)abstract
- Wheat starch carbamates of different degrees of substitution were produced in laboratory experiments and for the first time their film forming performance were investigated. The carbamation reaction between urea and starch was investigated using a factorial design. Long reaction time, 2 h, and high urea content, 10 and 25%, resulted in a high degree of substitution, 0.07 and 0.15, respectively. These starch carbamates were assumed to be cross-linked and showed best film forming properties resulting in continuous and firm films. Furthermore, a high degree of carbamate substitution favored a decrease in glass transition temperature (T-g) in cast films. The addition of acid as a catalyst for carbamation of starch produced inconsistent results and mainly lead to degradation of starch molecules that caused brittle films. FTIR and C-13 NMR analyses confirmed the covalent bonding between urea and starch in starch carbamates. In a final step, production of starch carbamates was successfully scaled up. A potential industrial use of these starches is as oxygen barrier in multilayer food packaging.
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| 17. |
- Muneer, Faraz, et al.
(författare)
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Innovative Gliadin/Glutenin and Modified Potato Starch Green Composites : Chemistry, Structure, and Functionality Induced by Processing
- 2016
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 4:12, s. 6332-6343
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we combined two wheat proteins, gliadin (Gli)/glutenin (GT), and modified potato starch (MPS) into composites using extrusion. In the Gli/GT MPS composites, we studied the structural dynamics of proteins and starch, protein starch interactions, protein properties, and composite morphology in relation to mechanical and barrier properties. Materials with different ratios of Gli/GT and MPS were extruded using either glycerol or glycerol water at 110 and 130 degrees C. For the first time, a hierarchical hexagonal structure of Gli proteins was observed in Gli MPS composite at both extrusion temperatures. The higher temperature (130 degrees C) induced a higher degree of protein cross-links, an increase in the polymer size, and formation of beta-sheets compared to 110 degrees C. The combination of plasticizers (glycerol and water) favored a micro-structural morphology with improved gelatinization of starch, processability, as well as strength, stiffness, and extensibility of GT MPS composites. The highest amount of the oxidized proteins was observed in the samples with the highest protein content and at high extrusion temperature. The Gli- and GT MPS (30/70) samples showed promising oxygen barrier properties under ambient testing conditions. These findings provide in-depth information for tailoring the structural functional relationship of the Gli/GT-potato starch composites for their promising use in designing various green materials.
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| 18. |
- Muneer, Faraz, et al.
(författare)
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Nanostructural Morphology of Plasticized Wheat Gluten and Modified Potato Starch Composites: Relationship to Mechanical and Barrier Properties
- 2015
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1526-4602 .- 1525-7797. ; 16:3, s. 695-705
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, we were able to produce composites of wheat gluten (WG) protein and a novel genetically modified potato starch (MPS) with attractive mechanical and gas barrier properties using extrusion. Characterization of the MPS revealed an altered chain length distribution of the amylopectin fraction and slightly increased amylose content compared to wild type potato starch. WG and MPS of different ratios plasticized with either glycerol or glycerol and water were extruded at 110 and 130 °C. The nanomorphology of the composites showed the MPS having semicrystalline structure of a characteristic lamellar arrangement with an approximately 100 Å period observed by small-angle X-ray scattering and a B-type crystal structure observed by wide-angle X-ray scattering analysis. WG has a structure resembling the hexagonal macromolecular arrangement as reported previously in WG films. A larger amount of β-sheets was observed in the samples 70/30 and 30/70 WG-MPS processed at 130 °C with 45% glycerol. Highly polymerized WG protein was found in the samples processed at 130 °C versus 110 °C. Also, greater amounts of WG protein in the blend resulted in greater extensibility (110 °C) and a decrease in both E-modulus and maximum stress at 110 and 130 °C, respectively. Under ambient conditions the WG-MPS composite (70/30) with 45% glycerol showed excellent gas barrier properties to be further explored in multilayer film packaging applications.
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| 19. |
- Olsson, Erik, 1984-, et al.
(författare)
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The effect of pH on hydrolysis, cross-linking and barrier properties of starch barriers containing citric acid
- 2013
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 98:2, s. 1505-1513
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Tidskriftsartikel (refereegranskat)abstract
- Green cross-linking of thermoplastic starch for food packaging applications has been intensely studied during the last decade as a method of producing water-insensitive renewable barriers. This work has shown how the barrier properties of paper coated with a barrier dispersion containing starch and citric acid were affected by the solution pH and the drying temperature. The barrier properties of the coated paper were linked to molecular properties showing both hydrolysis and cross-linking reaction of starch in the presence of citric acid at different solution pH and different reaction temperatures (curing) on cast films. 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. The water vapor transmission rate was significantly affected by the competition between these two reactions. Coated paper showed a minimum in water vapor transmission rate at pH was kept around 4 in 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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| 20. |
- Yilmaz Turan, Secil, et al.
(författare)
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Bio-based films from wheat bran feruloylated arabinoxylan : Effect of extraction technique, acetylation and feruloylation
- 2020
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Ingår i: Carbohydrate Polymers. - : Elsevier Ltd. - 0144-8617 .- 1879-1344. ; 250
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Tidskriftsartikel (refereegranskat)abstract
- This study demonstrates the potential of feruloylated arabinoxylan (AX) from wheat bran for the preparation of bioactive barrier films with antioxidant properties. We have comprehensively evaluated the influence of the structural features and chemical acetylation of feruloylated AX extracted by subcritical water on their film properties, in comparison with alkaline extracted AX and a reference wheat endosperm AX. The degree of substitution (DS) of AX had a large influence on film formation, higher DS yielded better thermal and mechanical properties. The barrier properties of AX films were significantly enhanced by external plasticization by sorbitol. Chemical acetylation significantly improved the thermal stability but not the mechanical or barrier properties of the films. The presence of bound ferulic acid in feruloylated AX films resulted in higher antioxidant activity compared to external addition of free ferulic acid, which demonstrates their potential use in active packaging applications for the preservation of oxygen-sensitive foodstuff. © 2020 The Author(s)
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| 21. |
- Yilmaz Turan, Secil, et al.
(författare)
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Modulating temperature and pH during subcritical water extraction tunes the molecular properties of apple pomace pectin as food gels and emulsifiers
- 2023
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Ingår i: Food Hydrocolloids. - : Elsevier B.V.. - 0268-005X .- 1873-7137. ; 145
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Tidskriftsartikel (refereegranskat)abstract
- This study explores the cascade extraction of polyphenols and pectins from apple pomace and their potential application as food emulsifiers. The extraction of polyphenols was achieved by a simple method using ethanol and resulted in remarkable antioxidant activity. Pectic polysaccharides were sequentially extracted (5, 10 and 15 min) using subcritical water at two different temperatures (120 °C and 140 °C) and three different pH conditions (pH 3.0, 5.0 and 7.0). Acidic pH resulted in higher pectin yields when combined with higher temperature, whereas neutral conditions were less selective towards pectin. Pectin with different branching patterns could be isolated by tuning the process conditions. Linear homogalacturonan (HG) was preferentially isolated at milder conditions, whereas more branched rhamnogalacturonan (RG-I) populations required longer extraction times. Subcritical water enabled the extraction of pectins with different degrees of methoxylation (DM) depending on the extraction pH, which enabled the production of pectin acid gels with varying rheological properties. Low DM pectin was directly recovered from apple pomace at lower pH, eliminating the need for its conventional derivatization from high DM pectin. The emulsifying properties of two apple pomace pectin fractions with high and low methoxyl content were compared; the pectin with higher methoxyl content showed higher emulsifying capacity and stability. This study demonstrates that the relative abundance of the different pectic domains and the methoxylation of pectin can be controlled by subcritical water extraction, which has important implications for the valorization of pectic-rich agricultural wastes into valuable food ingredients. © 2023 The Authors
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