Volatile compounds in the thermoplastic extrusion of bovine rumen

The volatile compounds of raw and extruded bovine rumen, extracted by dynamic headspace, were separated by gas chromatography and analyzed by GC-MS. Raw and extruded materials presented thirty-two volatile compounds. The following compounds were identified in raw bovine rumen: heptane, 1-heptene, 4-methyl-2-pentanone, toluene, hexanal, ethyl butyrate, o-xylene, m-xylene, p-xylene, heptanal, limonene, nonanal, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane and octadecane. The following compounds were identified in the extruded material: 1-heptene, 2,4-dimethylhexane, toluene, limonene, undecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane and nonadecane. Mass spectra of some unidentified compounds indicated the presence of hydrocarbons with branched chains or cyclic structure.

Technological properties of precooked flour containing coffee powder and rice by thermoplastic extrusion

Although Brazil is a country of tradition in both the production and consumption of coffee, the most of the coffee is consumed as a beverage, which reduces greatly the competitiveness on international market, for reducing the chances of supplying the product under other forms of consumption. Owing to that, the aim of this study was developing a precooked mixed flour containing coffee powder and rice for use in coffee flavored products. Mixtures of rice and coffee in the proportions of 900:100, 850:150 and 800:200 g, respectively, were processed in a single screw extruder (Brabender DS-20, Duisburg, German) and the effect of the extrusion process on the variables moisture content (16%, 18% and 20%) and temperature in the third extruding zone (140 °C, 160 °C and 180 °C) was studied. The results for expansion index ranged from 2.91 to 11.11 mm in diameter; the water absorption index from 4.59 to 6.33 g gel/g sample and the water solubility index varied from 4.05% to 8.57%. These results showed that, despite coffee powder influenced the variables studied, the expanded product after milling resulted in a extruded mixture with good absorption and water solubility indices, which favors the use of the precooked mixed flour for human consumption.

Produção biotecnológica de poli-hidroxialcanoatos para a geração de polímeros biodegradáveis no Brasil

In recent years, several studies have been developed in Brazil to produce biodegradable materials. A particular family of bacterial polymers, the polyhydroxyalkanoates (PHA), has received special attention. PHAs are thermoplastic, biodegradable, biocompatible, are synthesised from renewable resources and can substitute petrochemical plastics in some applications. Different aspects have been focused to increase productivity and to reduce the cost of PHA production: bacterial improvement, use of industrial by-products as raw material, bioreactor design, process operation strategies, downstream process, mathematical modelling, polymer characterisation, application and biodegradability of blends. A production process was transferred to industry and studies to produce new PHA by controlling monomer composition are in progress. All these aspects are presented in this review.

Nanocompósitos de poliuretana termoplástica e nanotubos de carbono de paredes múltiplas para dissipação eletrostática

Polyurethane/multi-walled carbon nanotube (MWCNT) nanocomposites have been prepared with nanotube concentrations between 0.01 wt% and 1 wt%. MWCNT as-synthesized samples with ~74 nm diameter and ~7 μm length were introduced by solution processing in the polyurethane matrix. Scanning electron microscopy (SEM) images demonstrated good dispersion and adhesion of the CNTs to the polymeric matrix. The C=O stretching band showed evidence of perturbation of the hydrogen interaction between urethanic moieties in the nanocomposites as compared to pure TPU. Differential scanning calorimetry and positron anihilation lifetime spectroscopy measurements allowed the detection of glass transition displacement with carbon nanotube addition. Furthermore, the electrical conductivity of the nanocomposites was significantly increased with the addition of CNT.

Blendas de PHB e seus copolímeros: miscibilidade e compatibilidade

Poly(hydroxybutyrate) and its copolymers are linear polyesters behaving as conventional thermoplastic materials. However, they are totally biodegradable and produced by a wide variety of bacteria from renewable sources. Some properties and high production cost are still preventing future applications. In an attempt to improve the properties and to reduce cost blending PHB with others polymeric materials is one of the most efficient method. In this paper, miscibility, compatibility, morphological and mechanical aspects of PHB blends will be reviewed. An extensive revision over twenty last years was realized about works of blends based on PHB and its copolymers.

Poliuretanos elastoméricos obtenidos a partir de aceite de ricino y almidón de yuca original y modificado con anhídrido propiónico: síntesis, propiedades fisicoquímicas y fisicomecánicas

Chemical modification of cassava starch was conducted through an acylation reaction by using pyridine and propionic anhydride to replace the functional groups of starch. Polyurethane elastomers were prepared using suspensions of the mixture obtained from castor oil and yucca starch that was modified by a propionic anhydride reaction. The suspensions were characterized by means of tests based on The Fourier Transform Infrared Spectroscopy and the Hydroxyl Index. The castor oil-AMP suspensions were used for the PU synthesis. The PUs were characterized by their physical-mechanical properties like tension- deformation and Shore A. hardness, thermal gravimetric analysis and swelling test. The density cross-linking of from swelling tests was determined by applying the Flory-Rehner equation.

1,3-propanodiol: produção, aplicações e potencial biotecnológico

1,3-propanediol is a high-value specialty chemical which has many industrial applications. Its main use is the production of the polymer polypropylene terephthalate, a thermoplastic used in the textile and automobile industries. The interest in 1,3-propanediol production from glycerol bio-conversion has increased after the employment of biodiesel by various countries, being produced by chemical synthesis from petroleum intermediates or biotechnologically by microbial fermentation. Glycerol is an abundant low-cost byproduct from biodiesel refineries, and it is the only substrate that can be naturally or enzymatically converted to 1,3-propanediol by microbial fermentation. In this review, information on 1,3-propanediol's importance, production and purification are presented, along with results from recent research on glycerol microbial conversion to 1,3-propanediol. The bio-production of this intermediate compound from glycerol is very attractive both economically and environmentally, since it allows the replacement of fossil fuels by renewable resources.

Closure of large wounds using rubber bands in rabbits

OBJECTIVE: to verify the effectiveness of the rubber elastic band in the treatment of large wounds of the body wall of rabbits by means of traction of its edges. METHODS: we studied 30 New Zealand rabbits, divided into three groups (n=10): Group 1- healing by secondary intention; Group 2- removal and eutopic repositioning of skin as full thickness skin graft; Group 3- Approximation of wound edges with elastic rubber band. In all animals, we removed a segment of the back skin and subcutaneous tissue down to the fascia, in accordance with an acrylic mold of 8cm long by 12cm wide. All animals were observed for 21 days. RESULTS: two animals of groups 1 and 2 had wound abscess. In Group 2, there was partial or total graft loss in 90% of animals. The complete closure of the wounds was observed in four animals of Group 1, six of Group 2 and eight of Group 3. There was no difference between the scar resistance values of groups 2 and 3, which were higher than those in Group 1. The scars of the three groups were characterized by the presence of mature connective tissue mixed with blood vessels and inflammatory infiltration, predominantly polymorphonuclear. CONCLUSION: the tensile strength of the wound edges with rubber elastic band is as efficient as the skin graft to treat rabbits' large body wounds.

Functional extruded snacks with lycopene and soy protein

In this work, the effects of thermoplastic extrusion process parameters (raw material moisture content and temperature) and the addition of functional ingredients (lycopene and soy protein) on quality characteristics of a base-formulation for extruded corn snacks were studied, with the objective of developing an easy-to-eat functional product. A single-screw Labor PQ 30 model Inbramaq extruder was used for extrusion and a central composite rotational design (CCRD) was followed. The independent variables were: i) percentage of soy protein isolate (0-30%); ii) percentage of lycopene preparation (0-0.1%); iii) raw material moisture content (20-30%); and iv) 5th zone temperature (100-150 °C). The expansion index reached maximum values with the lowest raw material moisture content (20%) and intermediate temperatures (approximately 125 °C). Instrumental hardness was higher with high moisture and low temperature; however, increasing the percentage of soy protein was beneficial for the texture of the product, reducing hardness. The red color intensity increased with the increase in lycopene content and moisture, and with the reduction of temperature. Sensory acceptance tests were carried out for two products, with maximum percentages of the functional ingredients, 20% moisture and temperatures of 125 and 137 °C, with greater acceptance for the product extruded at 125 °C.

Evaluation of the in vitro glycemic index of a fiber-rich extruded breakfast cereal produced with organic passion fruit fiber and corn flour

The aim of this study was to determine the influence of process parameters and Passion Fruit Fiber (PFF) addition on the Glycemic Index (GI) of an extruded breakfast cereal. A 2³ Central Composite Rotational Design (CCRD) was used, with the following independent variables: raw material moisture content (18-28%), 2nd and 3rd barrel zone temperatures (120-160 ºC), and PFF (0-30%). Raw materials (organic corn flour and organic PFF) were characterized as to their proximate composition, particle size, and in vitro GI. The extrudates were characterized as to their in vitro GI. The Response Surface Methodology (RSM) and Principal Component Analysis (PCA) were used to analyze the results. Corn flour and PFF presented 8.55 and 7.63% protein, 2.61 and 0.60% fat, 0.52 and 6.17% ash, 78.77 and 78.86% carbohydrates (3 and 64% total dietary fiber), respectively. The corn flour particle size distribution was homogeneous, while PFF presented a heterogeneous particle size distribution. Corn flour and PFF presented values of GI of 48 and 45, respectively. When using RSM, no effect of the variables was observed in the GI of the extrudates (average value of 48.41), but PCA showed that the GI tended to be lower when processing at lower temperatures (<128 ºC) and at higher temperatures (>158 ºC). When compared to white bread, the extrudates showed a reduction of the GI of up to 50%, and could be considered an interesting alternative in weight and glycemia control diets.

Processing and characterization of extruded breakfast meal formulated with broken rice and bean flour

The objective of this work was to develop an extruded breakfast product containing broken rice and split old beans and to verify the influence of the extrusion process on their physicochemical, technological, and sensory characteristic. The final product had a protein content of 9.9 g.100 g-1, and therefore it can be considered a good source of proteins for children and teenagers. The dietary fiber content of the final edible product was 3.71 g.100 g-1. Therefore, the breakfast meal may be considered as a source of dietary fiber according to Brazilian law . As for the technological properties, the extruded product presented an expansion index of 8.89 and apparent density of 0.25 g.cm-3. With regard to the sensory analysis, the acceptance average was ranked between 6.8 and 7.7, corresponding to the categories "liked slightly" and "liked very much". With regard to purchase intention, 79% of the panelists said they would certainly or possibly purchase the product. Broken rice and split old beans are interesting alternatives for the elaboration of extruded breakfast products presenting good nutritional, technological, and sensory qualities.

Stability and microbiological quality of rice bran subjected to different heat treatments

Rice bran is a byproduct commonly used for animal feeding; however its nutritional value and potential application in human diet have attracted market interest. Its preservation for safe use is still a challenge, so the objective of this study was to determine the quality of commercially available rice bran samples subjected to different heat treatments (extruding, parboiling, toasting, and microwave oven heating) in order to promote stabilization during storage under room temperature. Rice bran samples were collected from two industries, and each treatment was divided in three parts, each corresponding to three repetitions. All samples were evaluated for moisture content, total microorganisms, mold and yeast counting, hydrolytic rancidity, and lipase activity during 90 days of storage. Most of the heat treatments, including domestic and thermoplastic extrusion, generated products which may be used for human consumption under the tested conditions in terms of physicochemical and microbiological quality. The domestic treatments were more efficient in eliminating microorganisms or keeping them within acceptable limits. The toasted rice bran showed satisfactory results in terms of moisture, hydrolytic rancidity control, and lipase activity.

Characterization of pre-gelatinized rice and bean flour

The objective of this study was to develop a pre-gelatinized flour using a mixture of broken rice and split beans by thermoplastic extrusion, and to evaluate the physicochemical, nutritional, and technological quality of the final product. The extrusion parameters were maintained using three heating zones with temperatures of 30 ºC, 40 ºC, and 70 ºC; screw speed of 177 rpm; feed rate of 257 g/m, and circular matrix of 3.85 mm. The following characterization analyses were performed: physicochemical, nutritional, water absorption index (WAI), water solubility index (WSI), and paste viscosity. The pre-gelatinized rice and bean flour had an intermediate value of WAI, 7.51 g/g, and high WSI value, 24.61%. Regarding proteins, it was verified an average content of 12.9% in the final product. The amino acid contents found in the pre-gelatinized flour indicate that the mixture has the essential amino acids. It was also found that the pre-gelatinized flour supplies more than 60% of the essential amino acids recommended for children aged one to three years old. The gelatinized flour composed of broken rice and split beans is an alternative to the use of these by-products of the manufacture process of rice and beans to obtain a product with viable technological characteristics and high nutritional value.