A specific short dextrin-hydrolyzing extracellular glucosidase from the thermophilic fungus Thermoascus aurantiacus 179-5

The thermophilic fungus Thermoascus aurantiacus 179-5 produced large quantities of a glucosidase which preferentially hydrolyzed maltose over starch. Enzyme production was high in submerged fermentation, with a maximal activity of 30 U/ml after 336 h of fermentation. In solid-state fermentation, the activity of the enzyme was 22 U/ml at 144 h in medium containing wheat bran and 5.8 U/ml at 48 h when cassava pulp was used as the culture medium. The enzyme was specific for maltose, very slowly hydrolyzed starch, dextrins (2-7G) and the synthetic substrate (α-PNPG), and did not hydrolyze sucrose. These properties suggest that the enzyme is a type II α-glucosidase. The optimum temperature of the enzyme was 70°C. In addition, the enzyme was highly thermostable (100% stability for 10 h at 60°C and a half-life of 15 min at 80°C), and stable within a wide pH range. Copyright © 2006, The Microbiological Society of Korea.

Cyclodextrin glycosyltransferase production by the Bacillus sp., subgroup alcalophilus using a central composite design

Cyclodextrin glycosyltransferase (CGTase) activity was produced by the Bacillus sp., subgroup alcalophilus in a culture medium containing cassava starch. A central composite design and response surface methodology were used to study the influence of carbon source (cassava starch), nitrogen sources (yeast extract and tryptone) and sodium carbonate in the production medium. Assays were performed in 300 mL Erlenmeyer flasks containing 100 mL of production medium maintained in a shaker at 150 rpm at 35±1°C for 72 h of fermentation. The independent variables [0.75% cassava starch, nitrogen sources (0.375% yeast extract and 0.375% tryptone) and 1% Na2CO3] produced an enzyme activity of 96.07 U mL-1.© Academic Journals Inc.

Beta-carotene stability during drying and storage of cassava and sweet potato

The effect of blanching on the β-carotene stability during drying and storage of cassava and sweet potato was evaluated. The orange-fleshed sweet potato showed good retention of β-carotene during the blanching and drying (100% and 96%, respectively), but lower retention (84% and 91%) was observed in cassava. Cassava also showed lower β-carotene stability than sweet potato during the storage of unblanched dried samples. β-Carotene content of dried cassava was reduced from 8.6 μg/g to traces in 20 days of storage while the initial amount of dried sweet potato (463 μg/g) was reduced by about 45% (210 μg/g). Blanching did not affect the β-carotene retention during the drying, but enhanced the stability of this carotenoid during the storage of dried samples at room temperature, especially in cassava. The initial levels of blanched-dried cassava and sweet potato (7.8 and 513 μg/g, respectively) took 70 days to fall by around 50%.

Physicochemical properties of cassava starch oxidized by sodium hypochlorite

In this work, cassava starch was modified by treatment with sodium hypochlorite (NaClO) at different concentrations (0.8, 2.0 and 5.0 % of active chlorine) and selected physicochemical properties of the oxidized starches were investigated. The native and modified samples were evaluated considering moisture, carboxyl content, apparent viscosity, susceptibility to syneresis, mid-infrared spectroscopy and crystallinity index. The treatment with NaClO resulted in alterations in carboxyl content of the oxidized starches that increased with increasing concentration of the oxidant. Oxidized starches also showed higher susceptibility to syneresis, as assessed by the release of liquid during freezing and thawing. Apparent viscosity analysis showed decrease in peak viscosity of the oxidized starches. X-ray diffractograms showed that the oxidation influenced the extent of cassava starch relative crystallinity found to lie between 34.4 % (native) and 39.9 % (2.0 % active chlorine). The infrared spectra are sensitive to structural changes on starch macromolecules and presented characteristic peaks as C-O-C of the six carbon glucose ring absorbs at 1,150-1,085 cm -1 and due to axial deformation these bands changed with the crystal structure of the starch samples. © 2012 Association of Food Scientists & Technologists (India).

Edible coatings from native and modified starches retain carotenoids in pumpkin during drying

The goal of this study was to evaluate the effect of edible coating pre-treatments on the retention of provitamin A during pumpkin drying. The coatings used were based on native and modified maize and cassava starch. To evaluate the effects of these coatings, slices of 'Dry Rajada' pumpkin were dried at 70 °C both with and without starch coatings applied at 30 and 80-90 °C. Carotenoid content was determined through HPLC using a C 30 column. Significant losses (12-15%) of trans-α-carotene and trans-β-carotene were observed when slices were dried without the coating. Significant improvement of carotenoid content was observed for dehydrated slices that were previously coated with a native maize starch solution at 90 °C, as well as with a modified maize starch solution at 30 °C and also with a modified cassava starch solution at 90 °C. The application of these starch solutions probably produced a more uniform film that adhered to the slices, minimizing carotenoid degradation during pumpkin drying and, as a consequence, resulting in a product that can be considered a good source of provitamin A. © 2012 Elsevier Ltd.

Comparing submerged and solid-state fermentation of agro-industrial residues for the production and characterization of lipase by Trichoderma harzianum

Lipase production by Trichoderma harzianum was evaluated in submerged fermentation (SF) and solid-state fermentation (SSF) using a variety of agro-industrial residues. Cultures in SF showed the highest activity (1.4 U/mL) in medium containing 0.5 % (w/v) yeast extract, 1 % (v/v) olive oil and 2.5 C:N ratio. This paper is the first to report lipase production by T. harzianum in SSF. A 1:2 mixture of castor oil cake and sugarcane bagasse supplemented with 1 % (v/w) olive oil showed the best results among the cultures in SSF (4 U/g ds). Lipolytic activity was stable in a slightly acidic to neutral pH, maintaining 50 % activity after 30 min at 50 C. Eighty percent of the activity remained after 1 h in 25 % (v/v) methanol, ethanol, isopropanol or acetone. Activity was observed with vegetable oils (olive, soybean, corn and sunflower) and long-chain triacylglycerols (triolein), confirming the presence of a true lipase. The results of this study are promising because they demonstrate an enzyme with interesting properties for application in catalysis produced by fermentation at low cost. © 2012 Springer-Verlag and the University of Milan.

Optimization of the surimi production from Mechanically Recovered Fish Meat (MRFM) using response surface methodology

The by-products generated from industrial filleting of tilapia surimi can be used for the manufacture of surimi. The surimi production uses large amounts of water, which generates a wastewater rich in organic compounds (lipids, soluble proteins and blood). Optimizing the number of washing cycles will contribute to a more sustainable production. A mathematical model of mechanically recovered tilapia meat (Oreochromis niloticus) for the processing of surimi (minced fish washing cycles and tapioca starch addition) based on two quality parameters (texture and moisture) was constructed by applying the response surface methodology (RSM). Each factor had an important effect on the moisture and texture of surimi. This study found that the optimal formulation for producing the best surimi using the by-products of tilapia filleting in manufacturing fish burger were the addition of 10% tapioca starch and three minced fish washing cycles. A microstructural evaluation supported the findings of the mathematical model. Practical Applications: The use of mechanically recovered fish meat (MRFM) for the production of surimi enables the utilization of the by-products of filleting fish. However, the inferior quality of the surimi produced from MRFM in relation to that produced with fillets necessitates the addition of starch; secondly, surimi production consumes a large volume of water. RSM provides a valuable means for optimizing the number of washing cycles and starch amounts utilized in fish burger production. Tapioca starch, widely produced in Brazil, has desirable characteristics (surface sheen, smooth texture, neutral taste and clarity in solution) for use in MRFM-produced surimi. © 2013 Wiley Periodicals, Inc.

Seletividade de herbicidas à cultura da mandioca

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Obtenção de massa de mandioca com adição de maltodextrina de amido de milho Waxy

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Bioconversão energética da folha e bagaço de mandioca pelo fungo Rhizopus oligosporus para obtenção de alimento funcional

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Composição bromatológica e digestibilidade aparente da parte aérea seca da mandioca na alimentação de tilápias-do-nilo

The objective of this work was to evaluate the effect of sun and shade drying of the aerial part of cassava on the chemical composition and apparent digestibility coefficient (ADC) of nutrients, energy, and aminoacids for Nile tilapia (Oreochromis niloticus). There was no difference between the drying methods for chemical composition. The ADC of crude protein showed higher digestibility for the shade dried aerial part. Shade drying of the aerial part of cassava allows higher conservation of the protein content and better apparent digestibility of the protein and amino acid fraction for Nile tilapia.

Cassava and turmeric flour blends as new raw materials to extruded snacks

Short cooking time and ability to blend varieties of food ingredients have made extrusion cooking a medium for low-cost and nutritionally improved food products. The effect of moisture, extrusion temperature and amount of turmeric flour mixed with cassava flour on physical characteristic of puffed snacks was evaluated in this work. Extrusion process was carried out using a single-screw extruder in a factorial central composite design with four factors. Results showed effect of extrusion parameters on dependents variables. High expansion, low browning, low water solubility index, intermediate water absorption index and high crispness desirable characteristics to puffed snacks are obtained in conditions of 12% moisture, 5% turmeric flour, 105º C of temperature and 250 rpm of screw speed. These paper point to the potential still unexplored of the use of flours of cassava and turmeric as raw materials in the development of extruded puffed snacks.

Chemical Composition, Rumen Fermentation Kinetics, Digestibility and Energy Value of Cassava Leaves Hay at Different Storage Times

Cassava leaves have been widely used as a protein source for ruminants in the tropics. However, these leaves contain high level of hydro-cyanic acid (HCN) and condensed tannins (CT). There are evidences that making hay can eliminate more than 90% of HCN and that long-term storage can reduce CT levels. A complete randomized design with four replicates was conducted to determine the effect of different storage times (0-control, 60, 90 and 120 days) on chemical composition, in vitro rumen fermentation kinetics, digestibility and energy value of cassava leaves hay. Treatments were compared by analyzing variables using the GLM procedure (SAS 9.1, SAS Institute, Inc., Cary, NC). Crude protein (CP) and ether extract (EE) of the cassava hay were not affected (P > 0.05) by storage time (17.7% and 3.0%, respectively). Neutral detergent fiber, acid detergent fiber, total carbohydrate and non-fiber carbohydrate were not affected either (P>0.05) by storage time (47.5, 32.6, 72.3 and 25.8% respectively). However, other parameters were influenced. CT was lower (P<0.05) in hay after 120 days of storage compared with control (1.75% versus 3.75%, respectively). Lignin and insoluble nitrogen in neutral detergent, analyzed without sodium sulfite, were higher (P<0.01) after 120 days of storage, compared with the control (11.22 versus 13.57 and 1.65 versus 3.81% respectively). This suggests that the CT has bound to the fiber or CP and became inactive. Consequently, the in vitro digestibility of organic matter (50.36%), total digestible nutrients (44.79%) and energy (1.61 Mcal/KgMS), obtained from gas production data at 72 h of incubation, has increased (P<0.05) with storage times (56.83%, 51.53% and 1.86 Mcal/KgMS, respectively). The chemical composition and fermentative characteristics of cassava hay suffered variations during the storage period. The best values were obtained after 90 days of storage. This is probably due to the reduction in condensed tannins.

DIGESTIBLE ENERGY OF UNPEELED CASSAVA ROOT MEAL AND ITS EFFECT ON GROWTH PERFORMANCE AND CARCASS TRAITS IN RABBITS

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Componentes de produção e morfologia de raízes de mandioca sob diferentes preparos do solo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)