Search results for "Starch"
showing 10 items of 182 documents
Strength of cellulosic fiber/starch acetate composites with variable fiber and plasticizer content
2014
In this experimental study, the performance of injection-molded short flax and hemp fibers in plasticized starch acetate were analyzed in terms of strength. Parameters involved in the analysis are a variable fiber and plasticizer content. The measured strength of the composites varies in the range of 12–51 MPa for flax fibers and 11–42 MPa for hemp fibers, which is significantly higher than the properties of the unreinforced starch acetate matrix. The micro-structural parameters used in modeling of composite strength were obtained from optical observations and indirect measurements. Some of these parameters were qualitatively verified by X-ray microtomography.
BIOPOLYMERS USED AS EDIBLE COATING TO LIMIT WATER TRANSFER, COLOUR DEGRADATION AND AROMA COMPOUND 2-PENTANONE LOST IN MEXICAN FRUITS
2005
Low preservation of typical fruits in countries with warm weather represents a limitation to export. A recently proposed method to increase shelf-life of fresh guava, is the application of biopolymers as edible coatings. This research involves the use of biopolymers of microbial origin obtained with low cost nutrients, to prepare edible coatings applied on mexican guava and apricot. Dextrans obtained by fermentation with Leuconostoc mesenteroides isolated from a typical mexican beverage named pulque (cactus juice fermented). Dextrans were purified by precipitation with methanol and dispersed in purified water. This procedure was repeated 3 times to eliminate carbohydrates others than dextra…
The compound internal pyrenoid in cultured cells of the green algaMonoraphidium griffithii (Berkel.) Komar.-Legner.
1979
The chloroplast ultrastructure ofMonoraphidium griffithii (Berkel.) Komar.-Legner. has been studied in axenic cultures of various ages. The algae have grown in a complete nutrient solution (illumination about 3,000 lx) and on its agar medium (illumination about 600 lx). The large parietal cup-shaped chloroplast of the cells includes a multiformed compound internal pyrenoid that is situated, especially in older cells, in the central part of the chloroplast opposite to the dictyosome and the nucleus. The chloroplast thylakoids either reach the edge of the pyrenoid or penetrate its matrix and run there parallel in more or less long bits. Starch grains were not found to form any sheath around t…
Effects of Kinetin and Different Light Qualities on the Content of Carbohydrates
1983
Summary The effects of kinetin on the content of soluble redueing sugars, starch, soluble proteins and various components of the photosynthetic apparatus were studied with primary leaves of Sinapis alba, which were grown under different light qualities (white, red, blue Jight conditions). It was especially the content of soluble reducing sugars that was most influenced by kinetin. The enhancement of the sugar content was dependent on the duration of application as well as on the concentration of kinetin. The doseresponse curve shows that the sugar content strongly increased at low kinetin eoneentrations (0.01 to 1 mg · 1-1), whereas from 1 mg · 1-1 onwards the inerease was slower and linear…
Investigations on the Starch Content and Ultrastructure of Spruce Needles Relative to the Occurrence of Novel Forest Decline
1989
The starch content and ultrastructure of needles of Norway spruce trees [Picea abies (L.) Karst.] taken from three natural habitats, undamaged or with symptoms of novel forest decline, were investigated during the course of three years. The starch content was clearly dependent on the seasons, with a maximum in spring and a decline during summer and autumn, leading to a minimum in winter. Needles of damaged trees from one habitat exhibited in all three years from August to October a significantly higher starch content than their undamaged counterparts. Microscopic investigations of these needle samples exhibited severe damage symptoms to the phloem in macroscopically green needles, though mo…
Pharmacokinetics and pharmacodynamics of hydroxyethyl starch in hypovolemic pigs; a comparison of peripheral and intraosseous infusion.
1999
Intraosseous (i.o.) infusion is considered a useful technique for the administration of medications and fluids in emergency situations when peripheral intravascular access is not possible. This study investigated the effectiveness of i.o. versus intravenous (i.v.) infusion of hydroxyethyl starch (HES 200/0.5) in hypovolemic pigs. Twenty-three pigs (8- to 9-week-old) were anaesthesized, instrumented and blood was withdrawn (25-30 ml/kg) to50 mmHg mean arterial pressure (MAP). The animals were left untreated in haemorrhage for 30 min. Relevant haemodynamic parameters were monitored and blood samples were collected for blood gas and HES concentration analysis. Infusion of HES via i.v. or i.o. …
Potato pulp as a composting substrate
2014
Potato pulp is a waste, which is produced in considerable quantities by starch manufacturing industry. Addition of pulp fibre residue to soil results in beneficial effects on soil physical and biochemical properties. In this study, organic potato pulp was mixed with organic grass in three concentrations (75:25 (A), 50:50 (B) and 25:75 (C) % w/w) with the aim of comparing the dynamics of the composting process during a 30-day period. A mini-field experiment was conducted in 0.7 m 3 windrows which were left without covering and additional mixing during composting process, except sampling procedure. During 30-days’ experiment the C:N ratio decreased from 25÷30 to 13÷17 indicating the active co…
Methods for Separating Native Enzymes
1994
In the course of electrophoresis the stability of an enzyme depends on such conditions as (a) pH-value, (b) ion strength and ion species, (c) effector molecules, (d) temperature and (e) properties of the separation matrix. These parameters were empirically optimized for starch gel electrophoresis [1–3] and cellulose acetate electrophoresis [4, 5] when analyzing predominantly animal and human specimen. A major advantage of these types of separation media is that practically every buffer system can be used to separate enzymes whereas in disc-gel electrophoresis [6–8] the number of applicable buffer systems is limited. When using isoelectric focusing to separate native enzymes no buffer choice…
Creep and recovery experimental investigation of low oil content food emulsions
2008
Abstract Creep and recovery tests have been performed to study the viscoelastic behavior of low oil content food emulsions. Formulations of salad dressings usually include modified starch (MS) due to its low cost and the special creamy texture if affords. The combination of starch with other natural gums may improve the quality of the product. A reference emulsion containing 4% MS, and four other formulations in which the starch was partially replaced by xanthan gum (XG), locust bean gum (LBG) and two synergistic blends of these gums were formulated. Gels prior to emulsification were studied for comparative purposes. The viscoelastic behavior of all the systems was characterized by means of…
Durability of a strach-based biodegradable polymer
2007
Abstract The photo-oxidation and the photo-stabilization of a commercial biodegradable polymer have been investigated in order to establish the possibility of using this polymer as raw material for films for agriculture. The degradation has been followed by measuring the mechanical properties as a function of photo-oxidation time and in particular by following the elongation at break. The virgin polymer, made from maize starch and a synthetic biodegradable polyester, shows poor resistance to the UV irradiation as observed by the fast decay of the elongation at break, but the presence of small amounts of conventional UV stabilizers strongly improves the durability of this polymer. The UV sta…