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Heat Induced Gels from Coconut Press Cake Proteins

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Food and Nutrition Sciences 2014年第6期5卷 562-570页

作者： Borges Chambal Bjorn Bergenstah petr dejmek Faculty of Engineering Eduardo Mondlane UniversityDEQUIMaputoMozambique Department of Food Technology Engineering and Nutrition Lund UniversityLundSweden

Freeze-dried coconut press cake powder (CPP), 43% w/w protein, was used to investigate the heat-induced gelation by heating in rheometer to 75℃ in a wide range of pH values, from 4 to 9. Low strain oscillatory method applied the measure visco-elastic propertieson 15% w/w CPP. The gel strength was also assessed by a texture analyzer. SDS-PAGE electrophoresis was conducted to identify the proteins evolved in the gel network structure and the gel micro-structure was also evaluated. At low pH, the CPP proteins formed soft (elastic modulus <100 Pa) particulate gels prone to syneresis, with aggregate size of the order of 4.2 micrometers. In the alkaline region, homogenous gels were induced by heating. Gel strength started to increase dramatically from 64℃ to 67℃, for pH 9 and pH 8 respectively, reaching the maximum gel elastic modulus over 1000 Pa at pH 9. The SDS-PAGE showed that the polypeptide sub-unities at 24, 32 - 34 and 53 kDa were the most prominent in gelation.

关键词： Heat-Induced Gel Coconut Press-Cake Globular Proteins Rheology pH

Size Reduction of Hydrophobically Modified Starch on Beads Mill： Effect of Dispersing Medium and Milling Time

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Journal of Food Science and Engineering 2015年第3期5卷 103-111页

作者： Marcos Antonio Neves petr dejmek Isao Kobayashi Mitsutoshi Nakajima Faculty of Life and Environmental Sciences University of Tsukuba 1-1-1 Tennodai Tsukuba lbaraki 305-8572 Japan Food Engineering Division National Food Research Institute NARO 2-1-12 Kannondai Tsukuba Ibaraki 305-8642 Japan Department of Food Technology Engineering and Nutrition Lund University Box 124 SE 221 O0 Lund Sweden

The primary interest to this study was to investigate the effect of milling parameters on the size of hydrophobically modified starch particles, aiming to produce small, uniformly sized modified starch microspheres. Octie, a commercial product originated from cornstarch modified using Octenyl Succinate Anhydride （OSA）, was dispersed （3 wt%） using different media （water or ethanol） and subsequently wet-milled using a beads mill with zirconium beads at a rotation of 6,000 rpm up to 30 min. It was found that milling Octie in water dispersion for 3 min resulted in the smallest mean particle size （2.04 i 0.91 ktm）, compared to unmilled modified starch granules （15.2 ~ 6.0 lam）. Granular size and morphology changed considerably with further milling. For instance, very dense clusters with variable particle sizes （20.6 ~ 10.0 lam） were obtained after 30 min milling. As depicted by Scanning Electronic Microscopy, a large number of particles were apparently flattened during the milling process rather than broken, forming aggregates. Ultimately, within the range of experimental conditions tested, production of sub-micron modified starch particles was not possible.

关键词： Hydrophobic octenyl modified starch milling.

Improved Energy and Sensory Properties of Instant Porridge Made from a Roasted Mixture of Grated Orange-Fleshed Sweet Potatoes and Flour Made from Shredded Sun Dried Cassava

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Food and Nutrition Sciences 2014年第14期5卷 1430-1439页

作者： Irene Stuart Torrie de Carvalho Lucas Daniel Tivana Yvonne Granfeldt petr dejmek Food Technology Lund University Lund Sweden Food Technology Lund University Lund Sweden Chemical Engineering Department Eduardo Mondlane University Maputo Mozambique

Mozambican diets are often lacking in vitamin A. Orange-fleshed sweet potatoes (OFSP) are rich in beta-carotene, a precursor of vitamin A, but are not easily introduced into the diet as the consistency of the porridge made from OFSP is unappetising. Flour made from roasted cassava (garri) produces a palatable porridge with a high energy density. We propose a simple procedure for producing an instant porridge by roasting grated OFSP with flour from shredded sun-dried cassava (G-OFSP). This is an easily adopted variant of the traditional garri-making process. The consistency of this porridge made from milled G-OFSP (G-OFSPf) was compared to the consistency of porridges made from maize flour (Mf), cassava flour (Cf), OFSP flour (OFSPf) and garri flour (Gf) at 43°C, and then correlated to the perceived characteristics assessed by a sensory panel. The dry matter concentration of the porridges was adjusted to give similar consistency, measured by the maximum force of back extrusion, using traditional maize porridge as a reference. The porridges were additionally characterized by back extrusion force relaxation time. Short relaxation times were obtained for G-OFSPf, Mf and Gf porridges and longer times for Cf and OFSPf porridges, corresponding roughly to the sensory preference. In the sensory test of consistency, G-OFSPf porridge was ranked first, followed by Mf, Gf, OFSPf and Cf. In overall sensory tests comparing G-OFSPf porridge to Gf porridge, G-OFSPf porridge was significantly preferred with regard to all sensory attributes evaluated (p < 0.01). The energy density of the G-OFSPf porridge was 5.6 kJ/ml;the highest of the three most preferred porridges with regard to texture. The preparation of flour from a mixture of grated OFSP and shredded sun-dried cassava improved the perceived porridge consistency, increased its energy density, and its high acceptability would increase the intake of betacarotene.

关键词： Cassava Consistency Energy Density Garri Orange-Fleshed Sweet Potatoes

Predictability of the Consistency of Porridges Using Mixtures of Different Flours

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Food and Nutrition Sciences 2013年第9期4卷 933-939页

作者： Irene S. T. de Carvalho Yvonne Granfeldt Ann-Charlotte Eliasson petr dejmek Department of Chemical Engineering Eduardo Mondlane University Maputo Mozambique Department of Food Technology Engineering and Nutrition Lund University Lund Sweden. Department of Food Technology Engineering and Nutrition Lund University Lund Sweden.

The purpose of this study was to investigate the predictability of the consistency of blended porridges based on the volume fractions of separate porridges made from orange-fleshed sweet potato, cowpea, dehulled soybean, dehulled sorghum and maize flour (dehulled, commercial and germinated). Accurate predictions could be made for 13 of the 21 blends investigated. The consistency of porridge consisting of mixtures of cowpea with orange-fleshed sweet potato, and cowpea with dehulled soybean was lower than expected, and was attributed to the different size distributions of the swollen flour particles. Blends containing germinated maize showed significantly lower consistency than expected in both porridges with starchy continuous phase and porridges with proteinaceous continuous phase. It was thus concluded that both amylolytic and proteolytic activity are of importance in the ameliorating effects of germinated maize.

关键词： Back-Extrusion Consistency Flour Mixtures Porridge