High temperature AFM study of CAP 30/45 pen grade bitumen

Bitumen is a complex mixture of hydrocarbons for which microstructural understanding is incomplete. In an effort to detail this microstructure, a asphalt cement sample (CAP 30/45) was analysed by thermal phase detection atomic force microscopy. Phase contrast and topography images showed that sample morphology is highly dependent on temperature. The ‘bee structure’ changed considerably at temperatures between 50°C and 56°C. A decrease of the oscillation amplitude was observed upon heating and the ‘bees’ completely disappeared at temperatures above 57°C. When the temperature was decreased after melting at 170°C, the ‘bees’ began to nucleate gradually at temperatures of 57°C and its evolution with time was followed. Changes in morphology were compared to thermal analysis results and a model for the ‘bee’ structure was proposed.     

MOISTURE ADSORPTION BEHAVIOR OF BISCUITS FORMULATED USING WHEAT, OATMEAL AND PASSION FRUIT FLOUR

Moisture adsorption isotherms from a new biscuit considered as functional food were determined using a gravimetric static method at 25 and 40C and over a range of relative humidity from 0.112 to 0.903. The biscuit had 2.5, 3.3, 10.0 and 31.0% of ash, fiber, protein and fat, respectively, and 4.7% moisture content. The equilibrium moisture content of the biscuit (kg/kg) increased when the storage temperature at any given water activity ( A _w) was reduced. The experimental data were analyzed using different models, namely Guggenheim–Anderson–de Boer (GAB) (three-parameter relationships), Henderson and Oswin (both models with two parameters), which exhibited a sigmoid shape at the studied temperatures. The maximum isosteric heat of sorption was 21.6 kJ/mol, which exponentially decreased when the moisture content was increased. The GAB model was found to be the most suitable for describing the adsorption characteristics at the temperature and A _w range studied, according to the relative error and the coefficient determination.

PRACTICAL APPLICATIONS

This article describes the characterization of moisture adsorption behavior of a new biscuit considered as functional food. In general, the sorption behaviors of several foods have been studied extensively; nevertheless, a reduced number of published articles about biscuit sorption isotherms are found in the literature. The experimental data reported in this article may be important for the scientific community of the food science and technology. Isosteric heat of sorption is important for the determination of the binding strength of water to the food, as well as the amount of water present in the food.     

Leaf blade anatomy and ultrastructure of six <i>Simira</i> species (Rubiaceae) from the Atlantic Rain Forest,Brazil

Simira is a predominantly woody Neotropical genus comprising 41 taxa, 16 of which occur in Brazil and eight of them in the southeastern region of Brazil. Leaf blades of Simira eliezeriana Peixoto, S. glaziovii (K. Schum.) Steyerm., S. grazielae Peixoto, S. pikia (K. Schum.) Steyerm., S. rubra (Mart.) Steyerm., S. sampaioana (Standl.) Steyerm. were collected in the southeastern region of Brazil and fixed according to usual methods for light and electron microscopy. The leaf blades show typical characteristics of the Rubiaceae family as dorsiventral mesophyll and paracytic stomata. The presence of two bundle sheaths that extend to the upper epidermal layer, prismatic crystal and crystal-sand, alkaloids in the mesophyll and the organization micromorphological of the outer periclinal wall are considered characteristics representative for the genus. This study also demonstrates some leaf blade characteristics that can be used to Simira species identification (leaf surface, domatia types, epicuticular wax types and patterns of epidermis anticlinal cell walls).     

Characterization and Distribution of Aerobic, Spore-Forming Bacteria from Cacao Fermentations in Bahia

Aerobic spore forming bacteria isolated from traditional cacao fermentations in Bahia were identified in the genus Bacillus: B. subtilis, B. licheniformis, B. firmus, B. coagulans, B. pumilus, B. macerans, B. polymyxa, B. laterosporus, B. stearothermophilus, B. circulans, B. pasteurii, B. megaterium, B. brevis, and B. cereus. In the first 8 hr of the fermentations, similar percentages of ten species were found in the distribution. During the fermentation process the amount of spore-forming bacteria increased and B. subtilis, B. circulans, and B. licheniformis appeared more frequently.     

EFFECTS OF DIETARY SOYBEAN LECITHIN ON SOME SENSORY AND RHEOLOGICAL PROPER TIES OF FROZEN AND NON-FROZEN CHICKEN MEAT

Soy bean lecithin was added to practical rations fed to 144 broiler chicks. The dark and white meats from frozen and non-frozen carcasses were submitted to both mechanical (Warner Bratzler and Instron Universal Testing Machine) and sensory assessments of tenderness. A good correlation was observed between the two types of measurements. Regression equations indicated that higher lecithin contents in the rations decreased sensory toughness of the white meat. Freezing of the meats at – 40°C had little effect on texture.     

Sensory and Nutritional Properties of Cookies Based on Wheat-Rice-Soybean Flours Baked in a Microwave Oven

Three formulas of cookies prepared from 50:45:5 (I), 50:40:10 (II) and 50:35:15% (III) wheat flour, broken rice flour, and defatted soy flour, respectively, baked in a microwave oven (2450 MHz) for 240 sec, were rated as the best of six formulas for flavor and texture by a trained panel. Cookies of formulas I and II were preferred over formula III by a consumer-type panel. Cookies of all three formulas showed no significant differences in nitrogen balance, apparent biological protein value and apparent net protein utilization. Apparent protein digestibility and protein efficiency ratio were significantly higher in formulas II and III than in formula I.     

CHEMICAL COMPOSITION AND AMINO ACID CONTENTS OF BRAZILIAN BEANS (Phaseolus vulgaris)

SUMMARY— The chemical composition of 12 varieties of beans (Phaseolus vulgaris) was determined. Varieties most commonly found on Brazilian markets were chosen for this work. The average moisture content was 11%, ash 3.5%, fat 1%, protein 25%, starch 40%, crude fiber 4% and pentonsans 7%. The content of minerals in mg/100g sample was: phosphate 1000, iron 3.2, calcium 40 and magnesium 210. The content of essential amino acids in mg/g protein, calculated on a dry basis, was: lysine 72–106, threonine 46-61, valine 29–54, methionine 3–18, isoleucine 28-49, phenylalanine 33–118 and tryptophane 103-138. The product was rich in lysine and threonine as compared to the FAO table for essential amino acids require in the human diet. It was poor in methionine, isoleucine, valine, tryptophane and leucine.     

INFLUENCE OF PLATE TEMPERATURE AND MODE OF REHYDRATION ON TEXTURAL PARAMETERS OF PRECOOKED FREEZE-DRIED BEEF

The effects of various plate temperatures and rehydration procedures in texture of precooked freeze-dried beef, were evaluated. Frozen precooked commercial beef was freeze-dried at 20, 40, 60 and 80C during 24 h. The rehydration procedure involved two main variables: distilled water at room-temperature and at 80C, for 30 min. The texture profile analysis was performed with a TA-XT2 Texture Analyzer (SMS) for freeze-dried rehydrated samples and compared to frozen precooked beef. The results showed that with a same drying period, the 60C plate temperature and rehydrated in distilled water at room-temperature resulted in a better product texture, in regards to texture parameters hardness and chewiness.