Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Controlling rheology and structure of sweet potato starch noodles with high broccoli powder content by hydrocolloids
Silva, E. ; Birkenhake, M. ; Scholten, E. ; Sagis, L.M.C. ; Linden, E. van der - \ 2013
Food Hydrocolloids 30 (2013)1. - ISSN 0268-005X - p. 42 - 52.
scanning microscopy clsm - pasta products - wheat-starch - xanthan gum - nonstarch polysaccharides - sensory evaluation - cooking quality - lupin flours - corn starch - food gums
Incorporating high volume fractions of broccoli powder in starch noodle dough has a major effect on its shear modulus, as a result of significant swelling of the broccoli particles. Several hydrocolloids with distinct water binding capacity (locust bean gum (LBG), guar gum, konjac glucomannan (KG), hydroxypropyl methylcellulose (HPMC) and xanthan gum), were added to systems with 4 and 20% (v/v dry based) broccoli particles, and the effect of this addition on dough rheology, mechanical properties and structure of cooked noodles was investigated. Hydrocolloids with low (LBG and guar gum) and intermediate (KG) water binding capacity had no significant effect on shear rheology of the dough. Adding hydrocolloids with high water binding capacity (HPMC and xanthan gum) decreased the shear modulus of dough with 20% broccoli particles significantly. CLSM analysis of cooked noodles showed that in samples containing xanthan gum there was also an inhibition of swelling of starch granules. Strength and stiffness of cooked noodles with 20% broccoli particles were higher for samples containing xanthan gum, than samples without xanthan gum. The cooking loss and swelling index of samples with added hydrocolloids were slightly lower than samples without hydrocolloids. Our results showed that hydrocolloids with high water binding capacity can be used to control the degree of swelling of vegetable particles and starch granules in starch noodle products, and thereby control both dough rheology and textural properties of the cooked noodles
Formation of oil droplets in plasticized starch matrix in simple shear flow
Emin, M.A. ; Hardt, N.A. ; Goot, A.J. van der; Schuchmann, H.P. - \ 2012
Journal of Food Engineering 112 (2012)3. - ISSN 0260-8774 - p. 200 - 207.
polymer blends - rheological properties - newtonian drop - thermoplastic starch - extrusion-cooking - molecular-weight - sunflower oil - steady shear - corn starch - deformation
This paper describes the effect of simple shear flow on the formation of triglyceride oil droplets in a plasticized starch matrix. An in-house developed shearing device was used that enabled the application of controlled shear flow and rheological characterization of the native maize starch–triglyceride blends at shear stresses of up to 37 kPa. Due to the high viscosity of starch matrix, the viscosity ratio of the continuous starch phase and the dispersed triglyceride phase varied between 10-7 and 10-5. It was possible to create small droplets with a droplet diameter of 2.1 µm using simple shear flow only. An increase in shear rate had no influence on droplet diameter. However, an increase in oil content led to a vast increase in droplet diameter indicating the occurrence of coalescence. The results further show that the maximum stable droplet size in plasticized starch is significantly smaller (up to 100 times) than the predicted values for a Newtonian matrix. The differences of plasticized starch to Newtonian matrices are discussed in detail.
Prediction of the state diagram of starch water mixtures using the Flory--Huggins free volume theory
Sman, R.G.M. van der; Meinders, M.B.J. - \ 2011
Soft Matter 7 (2011)2. - ISSN 1744-683X - p. 429 - 442.
glass-transition temperatures - phase-transitions - aqueous-solutions - physicochemical properties - light-scattering - molecular-weight - corn starch - thermal characterization - crystalline polymorph - scanning calorimetry
In this paper we analyse the phase and state transitions of starch and other glucose homopolymers and oligomers using the free volume extension of the Flory–Huggins theory by Vrentas and Vrentas, combined with the Couchman–Karasz theory for the glass transition. Using scaling relations of model parameters with molar weight we have obtained accurate predictions of moisture sorption and the freezing, boiling, and melting data obtained from literature for starch, dextrans, pullulan and maltodextrins. With the estimated model parameters we can construct the complete state diagram for starch, which can now be used as a quantitative tool for design and analysis of food structuring processes.
In situ compatibilization of starch-zein blends under shear flow
Habeych Narvaez, E.A. ; Goot, A.J. van der; Boom, R.M. - \ 2009
Chemical Engineering Science 64 (2009)15. - ISSN 0009-2509 - p. 3516 - 3524.
corn starch - mediated oxidation - polymer blends - prediction - protein - water - strength - alcohols - kinetics
Starch-zein blends show poor adhesion between the two phases. Aldehyde starch was investigated as compatibilizer for these blends. Wheat starch was oxidized under mild conditions using sodium hypochlorite in the presence of the 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) and NaBr to prepare aldehyde starch. The oxidized starch was characterized by Nuclear Magnetic Resonance and Rapid Visco-Analyzer. Starch-zein blends plasticized with water and glycerol were prepared using simple shear flow in an in-house developed shearing device. Different zein ratios were tested to study the influence of aldehyde starch on the properties of the final material. The morphology of the blends was observed with confocal scanning laser microscopy and scanning electron microscopy. Tensile tests were used to evaluate the performance of the material. Both microscopy and tensile tests indicated that the blends had improved adhesion between the zein and starch phases, probably by reaction between the aldehyde groups in the starch molecules and zein. The aldehyde starch also influenced the properties of the starch matrix (higher viscosity, larger breakdown), which shows that physical or chemical crosslinks were formed inside the starch matrix
Optimization of the synthesis of 1-allyloxy-2-hydroxy-propyl-starch through statistical experimental design
Huijbrechts, A.M.L. ; Vermonden, T. ; Bogaert, P. ; Franssen, M.C.R. ; Visser, G.M. ; Boeriu, C.G. ; Sudhölter, E.J.R. - \ 2009
Carbohydrate Polymers 77 (2009)1. - ISSN 0144-8617 - p. 25 - 31.
corn starch - native corn - derivatives
The synthesis of 1-allyloxy-2-hydroxy-propyl starches was studied using a statistical experimental design approach. The etherification of two different granular maize starches with allyl glycidyl ether (AGE) in a heterogeneous alkaline suspension was investigated. The optimal reaction conditions were found via experimental design and the obtained response factor, e.g. the degree of substitution (DS) of the starch hydroxyl group, was statistically evaluated. The effects of six process factors on DS, namely the starch concentration, the reaction time, the temperature, and the amount of NaOH, Na2SO4 and AGE were investigated. The statistical analysis showed significant impact of the temperature, the amount of NaOH and the amount of AGE on the DS for both starches. Optimum conditions for the highest DS for waxy maize starch were: 0.0166% AGE (based on dry starch (ds)) and 1.0% NaOH (ds) at 34 °C in 4 h; on dent maize starch, these were 0.0099% AGE (ds) and 1.0% NaOH (ds) at 37 °C in 16 h.
Towards an optimal process for gelatinisation and hydrolysis of highly concentrated starch-water mixtures with alpha-amylase from B. licheniformis
Baks, T. ; Kappen, F.H.J. ; Janssen, A.E.M. ; Boom, R.M. - \ 2008
Journal of Cereal Science 47 (2008)2. - ISSN 0733-5210 - p. 214 - 225.
twin-screw extruder - wheat-starch - enzymatic-hydrolysis - extrusion-cooking - corn starch - sago starch - model - liquefaction - degradation - kinetics
The enzymatic hydrolysis of starch is usually carried out with 30¿35 w/w% starch in water. Higher substrate concentrations (50¿70 w/w%) were reached by using a twin-screw extruder for gelatinisation and for mixing enzyme with gelatinised starch prior to enzymatic hydrolysis in a batch reactor. The aim of this study was to determine which parameters are important for gelatinisation of wheat starch and to investigate the effects of different extrusion conditions on the enzymatic hydrolysis. After extrusion, the degree of gelatinisation was measured. During hydrolysis, the carbohydrate composition, the dextrose equivalent (DE) and the alpha-amylase activity were measured. Gelatinisation measurements showed that mechanical forces lowered the temperature required for complete gelatinisation. During hydrolysis experiments, high DEs were observed even if starch was not completely gelatinised during extrusion. Due to high substrate concentrations, the residual alpha-amylase activity remained high throughout enzymatic hydrolysis, although high temperatures were used. Increased substrate concentrations did not affect the carbohydrate composition of the product. Furthermore, the time required for the batch hydrolysis step could be varied by choosing a different enzyme-to-substrate ratio. This article provides a basis for detailed optimisation of this process to develop an industrial-scale process at high substrate concentrations.
Characterization of differently sized granule fractions of yellow pea, cowpea and chickpea starches after modification with acetic anhydride and vinyl acetate
Huang, J. ; Schols, H.A. ; Jin, Z. ; Sulmann, E. ; Voragen, A.G.J. - \ 2007
Carbohydrate Polymers 67 (2007)1. - ISSN 0144-8617 - p. 11 - 20.
canavalia-ensiformis starch - waxy maize starches - physicochemical properties - potato starches - retrogradation properties - enzymatic digestibility - physical-properties - noodle quality - rice starch - corn starch
The effect of reagent type on the properties of acetylated starches was studied for yellow pea, cowpea and chickpea starches after modification with acetic anhydride and vinyl acetate. Samples modified with vinyl acetate showed higher swelling volume and peak viscosity than those acetylated with acetic anhydride for the same starch. In addition, the reagents reacted differently towards granules having different sizes as present in un-fractionated starch. After sieving of the acetylated starches, the degree of substitution (DS) differed for the differently sized starch granules acetylated by the rapidly reacting acetic anhydride but not for the size fractions obtained from the starches acetylated by the slowly reacting vinyl acetate. Smaller size granule fractions exhibited larger swelling volume and higher peak viscosity as compared with the corresponding larger size fractions. The reagent type and granule size are important factors for pasting and swelling behaviours of acetylated granular starches.
Starch hydrolysis under low water conditions: a conceptual process design
Veen, M.E. van der; Veelaert, S. ; Goot, A.J. van der; Boom, R.M. - \ 2006
Journal of Food Engineering 75 (2006)2. - ISSN 0260-8774 - p. 178 - 186.
thermostable alpha-amylase - niger glucoamylase-i - twin-screw extruder - enzymatic-hydrolysis - extrusion-cooking - corn starch - reactor - kinetics - glucose - liquefaction
A process concept is presented for the hydrolysis of starch to glucose in highly concentrated systems. Depending on the moisture content, the process consists of two or three stages. The two-stage process comprises combined thermal and enzymatic liquefaction, followed by enzymatic saccharification. The three-stage process starts with shear induced melting of starch, followed by enzymatic liquefaction and saccharification. At a low moisture content, the shear stress needed to completely melt corn starch is so high that significant enzyme inactivation cannot be avoided, which leads to a need for separating starch melting and liquefaction in two separate processing steps. Assuming the use of currently available enzymes, the final product composition was estimated to contain 69-93% glucose, starting with respectively 65% and 35% dry starch. These results showed that the formation of side-products, mainly isomaltose and isomaltotriose, increased with increasing dry matter content. Increasing the dry matter content from 35% to 65% resulted in increasing reactor productivity of 17%, while the amount of water that should be removed from the system was reduced by 87%. (c) 2005 Elsevier Ltd. All rights reserved.
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