Modificação enzimática da farinha de arroz visando a produção de amido resistente

The aim of this work was to study the enzymatic modification on rice flour using lipase pancreatic and amyloglucosidase to obtain resistant starch. For this, Response Surface Methodology (RSM) was used to determine the best operating conditions for each enzyme. For lypase pancreatic, the highest value for resistant starch (45%) was achieved within 2 h reaction at pH 7 using an enzyme/substrate ratio of 4% (w/w) and Dp= 100/200 tyler. For amyloglucosidase, optima conditions corresponded to an enzyme/substrate ratio of 0,006 mL/g and Dp= 100/200 tyler at 45 ºC, yielding 57% of resistant starch in 2 h reaction. These results show the potential of using both enzymes to modified rice flour, increasing the resistant starch in about 5.7 folds in relation to the flour without treatment (resistant starch=10.6%).

Determinação de Mn e Zn em arroz empregando espectrometria de fluorescência de raios x de energia dispersiva

A simple, fast and inexpensive method was developed to determine essential elements in pellets of rice samples using energy dispersive X-ray fluorescence spectrometry (EDXRF). The accuracy and precision were evaluated using Standard Reference Material (rice flour NIST 1568a), and yielding relative standard deviation below 5%. The paired t-test showed good agreement within 95% confidence values. The detection limits (3σ) of Mn and Zn were 5.1 and 2.2 mg kg-1, respectively. The proposed method proved to be effective when used to determine Mn and Zn in commercial samples of rice without go by stage of decomposition.

Influence of substrates, light, filter paper and pH on the sporulation of Cercospora sojina

Fungi require special substrates for their isolation, vegetative growth and sporulation. In experiments conducted in the laboratory, the influence of substrates, light, filter paper and pH on the sporulation of Cercospora sojina conidia, the causal agent of soybean frogeye leaf spot, was assessed. The media potato sucrose agar, V-8 agar, tomato extract agar, soybean leaf extract agar, soybean seed extract agar, soybean meal agar, soybean flour agar and wheat flour agar were tested, added on the surface, with and without filter paper and under two light regimes, with 12 h light at 25°± 2°C and in the dark. A triple factorial 8x2x2 (substrates x light/dark x with/without filter paper) design with four replicates was used. V-8 agar medium was employed and the pH was adjusted with HCl 0.1N or NaOH 0.1N before autoclaving to the values: 3, 4, 5, 6, 7 and 8, and the pH of V-8 agar medium is 6.7. The evaluation was done on the seventh day of incubation. Data underwent regression analysis. Sporulation was maximized on the agar media V-8, seed extract, oat flour, tomato extract, and potato sucrose in the presence of filter paper and 12h light. On V-8 medium, maximal sporulation was obtained with pH 6.7.

Influence of irrigation on wheat crop

The use of irrigation has been increased significantly in wheat crops in Brazil. This study aims to evaluate the effect of irrigation on the productivity, on flour technological quality and on the wheat root system. In a field experiment conducted at IAPAR, in Londrina -state of Paraná (PR), Brazil, the IPR 118 cultivar was grown under sprinkler irrigation (Irrigated Treatment) and without irrigation (Non-irrigated Treatment). The productivity was determined by harvesting three samples of 25 m² per treatment. The same samples were used to evaluate the flour technological quality, considering, among other parameters, gluten strength (W). The evaluation of the root system was performed after the harvest, considering a profile of 0 to 45 cm of soil depth, and sampling eight plants per treatment. The profile wall method was used to determine the roots number (RN) and the monolith method to determine the root dry mass (RDM). Irrigation increased wheat productivity in three times, while W was reduced in the flour. Nevertheless, the value of W found in the Irrigated Treatment (249 10-4 J) was sufficient to keep wheat classification as bread type, the same as IPR 118 cultivar is classified. The measured values of RN and RDM were similar or higher for the Non-irrigated Treatment.

Leiomiossarcoma de jejuno

We describe a case of leiomyosarcoma of the jejunum in which abdominal computed tomography showed an intestinal tumor with a "sui generis" metalic artefact inside, which made us think of a benign disease (foreign body granuloma), because the patient lived in the rural area and he had a manioc flour mill, which is one the basic foods of the majority of the population of the north in Brazil. Because of the aspect of the tumor, we decided on a large scale resection, considering the possibility of a malignant tumor since we don't have frozen sections. This assured us of an adequate treatment for the tumor. This type of pathology should be remembered even though it only accounts for 0,2-2% of the intestinal tract tumors.

Brazilian soybean Glycine max (L.) Merr. cultivars adapted to low latitude regions: seed composition and content of bioactive proteins

Among the goals of the Brazilian soybean improvement programmes, the breeding strategies for cultivars adapted to low latitudes have been included to extend crop areas and to increase production. Seeds of nine Brazilian soybean cultivars adapted to low latitudes were investigated regarding to their composition, and amino acid and antinutritional/toxic protein contents. Protein (394.5 ± 13.1 to 445.3 ± 8.0 g kg-1 dry matter) and oil (200.6 ± 1.2 to 232.3 ± 4.7 g kg-1 dry matter) contents showed low correlation to each other (r = -0.06). The total carbohydrate (141.7 ± 6.1 to 211.1 ± 15.0 g kg-1 dry matter) and ash contents (48.2 ± 4.2 to 52.2 ± 0.5 g kg-1 dry matter) were similar to data available for other soybean cultivars. All soybean cultivars presented low levels of tryptophan and sulphur amino acids. The lectin (1,152 to 147,456 HU kg-1 flour), trypsin inhibitor (34.45 ± 2.28 to 77.62 ± 2.63 g trypsin inhibited kg-1 flour), toxin (6,210 ± 134 to 34,650 ± 110 LD50 kg-1 flour) and urease (0.74 ± 0.02 to 1.22 ± 0.10 g kg¹ flour) presented variations in their contents amongst the cultivars. Compared to other soybean cultivars, urease was higher, the acute toxicity lower and the lectin and trypsin inhibitor contents similar to data available. In general, soybean cultivars showed similar biochemical composition to those developed in different geographic regions. The relevance of these findings to the agronomic features and to choice of soybean cultivars to be used as food or feed is discussed.

Identification of Albizia lebbeck seed coat chitin-binding vicilins (7S globulins) with high toxicity to the larvae of the bruchid Callosobruchus maculatus

Seed coat is a specialized maternal tissue that interfaces the embryo and the external environment during embryogenesis, dormancy and germination. In addition, it is the first defensive barrier against penetration by pathogens and herbivores. Here we show that Albizia lebbeck seed coat dramatically compromises the oviposition, eclosion and development of the bruchid Callosobruchus maculatus. Dietary supplementation of bruchid larvae with A. lebbeck seed coat flour causes severe weight loss and reduces survival. By means of protein purification, mass spectrometry and bioinformatic analyses, we show that chitin-binding vicilins are the main source of A. lebbeck tegumental toxicity to C. maculatus. At concentrations as low as 0.1%, A. lebbeck vicilins reduce larval mass from 8.1 ± 1.7 (mass of control larvae) to 1.8 ± 0.5 mg, which corresponds to a decrease of 78%. Seed coat toxicity constitutes an efficient defense mechanism, hindering insect predation and preventing embryo damage. We hypothesize that A. lebbeck vicilins are good candidates for the genetic transformation of crop legumes to enhance resistance to bruchid predation.

LENTIL TANNIN-GLOBULIN INTERACTIONAND AND IN VITRO HYDROLYSIS

Protein fractions were isolated from lentil cotyledons and tannins were isolated and purified from lentil seed coats. The globulin fraction corresponded to 42.7% of the total lentil flour nitrogen, representing the major protein fraction. Acetone:water (7:3) was the best extractant for seed coat tannins compared to methanol or methanol-HCl 1%. Native and heated (99oC/15 min.) isolated lentil globulin and casein were hydrolyzed with trypsin and pepsin in the absence of tannins and at 1:40, 1:20, 1:10, 1:5 and 1:2.5 tannin-to-protein ratios. The tryptic and peptic hydrolysis of the unheated proteins were reduced with increasing tannin-to-protein ratios. Unheated casein showed to be more susceptible to trypsin than globulin and the opposite effect was observed with pepsin. Heating followed by tannin interaction and hydrolysis had a more pronounced effect on tryptic than peptic digestion for both proteins.

Functional characterization of acetylated Brazil nut (Bertholletia excelsa HBK) kernel globulin

Defatted Brazil nut kernel flour, a rich source of high quality proteins, is presently being utilized in the formulation of animal feeds. One of the possible ways to improve its utilization for human consumption is through improvement in its functional properties. In the present study, changes in some of the functional properties of Brazil nut kernel globulin were evaluated after acetylation at 58.6, 66.2 and 75.3% levels. The solubility of acetylated globulin was improved above pH 6.0 but was reduced in the pH range of 3.0-4.0. Water and oil absorption capacity, as well as the viscosity increased with increase in the level of acetylation. Level of modification also influenced the emulsifying capacity: decreased at pH 3.0, but increased at pH 7.0 and 9.0. Highest emulsion activity (approximately 62.2%) was observed at pH 3.0 followed by pH 9.0 and pH 7.0 and least (about 11.8%) at pH 5.0. Emulsion stability also followed similar behavior as that of emulsion activity.

Effect of chickpea (Cicer arietinum L.) germination on the major globulin content and in vitro digestibility

Chickpea seed germination was carried out over a period of 6 days. Little variation in the nitrogen and total globulin content was observed. The major globulin (11 S type) showed higher variation after the 4th day of germination. The elution behaviour and distribution of the isolated major globulin fraction on Sepharose CL-6B chromatography showed little modification at the end of germination. On SDS-PAGE the peak eluted from Sepharose CL-6B showed changes in protein bands between 20 and 30 kDa and above 60 kDa, indicating protein degradation during the period. Proteolytic activity was detected in the albumin fraction of the seeds, which increased up to the fourth and then decreased up to the sixth day, when isolated chickpea total globulin and casein were used as substrates. Chickpea flour, isolated albumin and total globulin fractions did not show an increase for in vitro digestibility; however, the isolated major globulin was more susceptible to hydrolysis after germination.

Oat hulls treated with alkaline hydrogen peroxide associated with extrusion as fiber source in cookies

Cookies were prepared with the replacement of 20% of wheat flour by chemically (alkaline hydrogen peroxide) and physically (extrusion) treated oat hulls, with the objective to investigate the possibility of use of this modified material. Cookies elaborated with the untreated hulls were used as control. Cookies were evaluated for their physical (spread ratio, specific volume and color) and sensory characteristics, and no difference was detected (p<0.05) among the cookies in relation to the physical properties. Triangule test, used to verify difference (p<0.05) among treated and untreated cookies, confirmed the efficiency of the treatment in sensory level. The acceptance level of cookies with treated fiber was evaluated by potential consumers of the product, obtaining 91% acceptance. The cookies presented 10.6 g of dietary fiber per 100 g of product.

Obtention and characterization of gluten-free baked products

This work had as objective the development of gluten-free breads and muffins using rice flour and maize and cassava starches. From seven samples resulting from a Simplex-Centroid design, the sensory and instrumental analyses of specific volume, elasticity, and firmness were performed. For the sensory analysis, the optimized formulation contained 50% of rice flour and 50% of cassava starch, and for the instrumental evaluation, the optimal simultaneous point for the three conducted analyses were 20% of rice flour, 30% of cassava starch, and 50% of maize starch. A comparative analysis of specific volume, elasticity, firmness, and triangular test was performed with pre-baked, baked, and frozen bread. Physicochemical, nutritional, and microbiological analyses were performed for both bread and muffin according to the Brazilian legislation.

Effects of different concentrations of passion fruit peel (Passiflora edulis) on the glicemic control in diabetic rat

Diabetes mellitus, an endocrine disorder, is the major cause of morbidity in developing countries, and it is considered the fourth leading cause of death worldwide. The conventional therapy for diabetes is insulin treatment. The peel of the Passion fruit is rich in fiber and prevents the absorption of carbohydrates, and thus can control and reduce the blood sugar rate. The objective of this study was to analyze the effect of the passion fruit peel flour on the glicemia of diabetic rats, as well as to study the probable action mechanisms. Wistar rats were used in the experiment and were offered the flours of the passion fruit peel in three concentrations: 5, 10, and 15%, and a casein diet as control. The most significant effect on the reduction of the glicemic rate was obtained with the 5% diet. The best values of hepatic glycogen were found in the 5 and 10% diets. The results of this study suggest that the 5% passion fruit flour diet was the one that provided the best reduction of blood glucose levels (59%) and the higher increase of the hepatic glycogen level (71%). The conversion of blood glucose into hepatic glycogen was considered the probable action mechanism involved.

Characterization of Brazilian wheat cultivars for specific technological applications

Functional and technological properties of wheat depend on its chemical composition, which together with structural and microscopic characteristics, define flour quality. The aim of the present study was to characterize four Brazilian wheat cultivars (BRS Louro, BRS Timbauva, BRS Guamirim and BRS Pardela) and their respective flours in order to indicate specific technological applications. Kernels were analyzed for test weight, thousand kernel weight, hardness, moisture, and water activity. Flours were analyzed for water activity, color, centesimal composition, total dietary fiber, amylose content and identification of high molecular weight glutenins. The rheological properties of the flours were estimated by farinography, extensography, falling number, rapid visco amylography, and glutomatic and glutork equipment. Baking tests and scanning electron microscopy were also performed. The data were subjected to analysis of variance and principal component analysis. BRS Timbauva and BRS Guamirim presented results that did not allow for specific technological application. On the other hand, BRS Louro presented suitable characteristics for the elaboration of products with low dough strength such as cakes, pies and biscuits, while BRS Pardela seemed suitable for bread and pasta products.

Physicochemical characteristics and functional properties of vitabosa (mucuna deeringiana) and soybean (glycine max)

Physicochemical characteristics and functional properties of vitabosa flour (Mucuna deeringiana) and soybean flour (Glycine max) were determined. Oil absorption capacity was higher in vitabosa. Water absorption capacity was higher in soy and it was affected by the change in the ionic strength of the medium. Emulsifying Activity (EA) decreased with increasing concentration of flour, while Emulsifying Stability (ES) showed an increased. EA and ES of flours have more ionic strength in the range between 0.0 and 0.4 M, but it is reduced afterwards with the higher concentration of NaCl. Foaming stability varied with the concentration of flour solution reaching maximum values of 39 and 33% for vitabosa and soybean, respectively at 10% flour concentration.Vitabosa had the best foaming capacity (56% to 0.6 M) compared with soybeans (47% to 0.4 M). Maximum capacity of gelation was observed in vitabosa at 10% flour concentration. Increases in ionic strength of the flour solution, at low salt concentrations (<0.4 M), improved the gelation of flours.