STUDY ON INTERACTION AMONG EXTRUSION-COOKING PROCESS VARIABLES AND ENZYME ACTIVITY: EVALUATION OF EXTRUDATE STRUCTURE

A blend of wheat flour (moisture content 11.61%) and different amounts of two commercial enzymes like GRINDAMYL (GA) amylase 1000 (0–0.1 g/kg) and GA protease 41 (0–1.0 g/kg) were extruded through a co-rotating twin-screw extruder.
The effects of barrel temperature (60–120C), dough moisture (20–36%), screw speed (100–400 rpm) and different amounts of enzymes on structure of extrudates (porosity and break strength) were studied using response surface methodology.
Results showed that the highest value of porosity (62.47%  ±  4.07) was obtained at the highest value of barrel temperature (120C) and at the largest amounts of GA protease 41 (1.0 g/kg) or GA amylase 1000 (0.1 g/kg). However, the simultaneous addition of large amounts of both enzymes caused a negative effect on expansion degree (porosity  <  30%). Large amounts of moisture dough and GA amylase 1000 resulted in a high value of break strength (25.7 N/mm²) and in stiff-textured extrudates .

PRACTICAL APPLICATIONS

This research could provide some information about the effects of and the interactions between extrusion parameters and enzyme activities, which are commonly used to produce bakery products, in order to improve the texture of extrudates processed at low barrel temperatures, i.e., 60C, for example, extrudates with thermolabile components like vitamins or extrudates with high lipid fraction like breakfast cereals, pet food, etc.     

Perceived texture: direct and indirect methods for use in product development

Increasing consumer interest in texture has made it of primary concern in product development, since manipulating texture can provide product differentiation. Successful development requires both comprehensive understanding of texture as perceived by the consumer, and appropriate measurement methods. Perceived texture results from an array of sensory inputs, arising before and during consumption. Sensory analysis methods provide means to express such percepts, but can be time-consuming and expensive. There are relationships between physiological parameters measured in individuals during food consumption, and perceived texture. Such measures can provide simple and rapid indices of texture, if validated before use, as routine tools in product development applications.     

SENSORY RESTRICTION WITH ISOLATION EXPERIENCES IN CHILDREN WITH PHENYLKETONURIA.

COMPARED 2 GROUPS OF CHILDREN WITH PHENYLKETONURIA, THOSE WITH A HISTORY OF EARLY SENSORY RESTRICTION OR ISOLATION AND THOSE WITHOUT, ON: (1) INTERPERSONAL BEHAVIOR, (2) LANGUAGE COMPREHENSION, (3) INTELLIGENCE, AND (4) INCIDENCE AND SEVRITY OF PERSONALITY DISTURBANCES. THE FINDINGS, DISCUSSED IN THE CONTEXT OF SENSORY-DEPRIVATION AND SENSORY-RESTRICTION RESEARCH, SUPPORTED THE HYPOTHESIS THAT EARLY ALTERATIONS IN SENSORY ENVIRONMENT LEAD TO LATER IMPAIRMENT IN INTERPERSONAL, EMOTIONAL, AND INTELLECTUAL FUNCTIONING. THE DEGREE OF THIS IMPAIRMENT WAS FOUND TO BE RELATED TO AGE AT THE TIME OF THE EARLY STRESS EXPERIENCE, BUT NOT TO THE DURATION OF SENSORY RESTRICTION OR ISOLATION. (34 REF.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Apple Juice Flavor Compound Sorption by Sealant Films

Heat sealant films investigated were: a commercial low density polyethylene (LDPE) and two developmental films, an ethylene/vinyl alcohol copolymer of high ethylene content and a co-polyester. Four flavor compounds, (ethyl-2-methylbutyrate, hexanal, trans-2-hexenal and 1-hexanol), were selected as representative of apple juice flavor components. Sorption was determined by a dynamic headspace technique, following direct contact between the polymer film samples and juice. Concentration of flavor compounds in the juice following contact with the film samples was determined as a function of time. Sorption of the components from juice was significant for LDPE, but not for the developmental films. Thus, either of the two developmental films would reduce loss of apple juice volatiles due to sorption.     

AN ECOLOGICAL STUDY OF A REGULATED PRAIRIE STREAM IN WESTERN MONTANA

Longitudinal and seasonal changes in biophysical variables were examined in this seminal study of an intermountain (Palouse) prairie stream. Hypolimnial releases from an irrigation reservoir controlled discharge, temperature and other habitat variables, thereby influencing distribution and abundance of zoobenthos. Dramatic changes in turbidity and nutrient concentrations occurred during the spring runoff and summer irrigation periods and following wind-driven sediment resuspension in the reservoir. Seasonal changes in the relative dominance of certain macroinvertebrate taxa were correlated with physical and chemical dynamics. Based on detrended correspondence analysis (DCA), specific conductance, temperature, dissolved oxygen and nitrates + nitrites were the variables most associated with seasonal macroinvertebrate biomass. Changes in taxa composition downstream from the dam were mainly related to species additions from site to site. Changes in pH and substratum were associated with longitudinal changes in biomass. For instance, the observed bimodal distribution of Cheumatopsyche sp. was correlated with percentage boulder substratum among the sites. On the other hand, DCA performed on macroinvertebrate densities emphasized pH, total ammonia, discharge and substratum. Species composition throughout the prairie segment of the stream was very different from that in the mountain canyon segment. The effects of regulation ameliorated significantly in a downstream direction from the dam. Presence of warm water species (e.g. Helicopsyche sp.) upstream and downstream of the reservoir were indicative of the native stream fauna of the intermountain prairies. Faunal responses to the ‘recovery’ gradient downstream from the dam provided a basis for the development of remedial management actions.     

COVALENT IMMOBILIZATION OF HEPARIN ON POLYMETHYLACRYLATE SURFACES

Heparin, a natural anticoagulant, was immobilized via covalent bonds on the surface of polymethylacrylate (PMA) beads to create a blood-compatible surface. Two chemical routes were utilized for immobilization. In the first route, PMA was hydrolyzed to produce functional carboxyl groups on its surface and heparin was covalently linked to these surface carboxyl groups by making use of carbodiimide chemistry. This method utilizes the free amino groups on heparin: the coupling occurs in minutes. In the second route, free amino groups were fixed to surface-hydrolyzed PMA by coupling one end of a suitable alkyl diamine with a water-soluble carbodiimide. Heparin was first ionically adsorbed to this aminated surface and then attached by glutaraldehyde fixation. This process occurs within one hour. In both techniques, more crude heparin (“Stage 14”) was bound than highly purified heparin due to larger number of free amino groups in crude heparin. The extent of heparin coupling was determined with ¹⁴C-labelled heparin. In vitro blood tests indicate that these surfaces are platelet compatible and are good candidates for nonthrombogenic materials.     

RELATIONSHIPS AMONG CHEMICAL, COOKING AND COLOR PROPERTIES OF BEEF PATTIES COOKED TO FOUR INTERNAL TEMPERATURES

A study involving five laboratories and nationwide sampling of ground beef was undertaken to determine cooking and color properties of patties cooked to 52.7, 65.6, 71.1 and 79.4C. The design of the study included purchase location (local, distant) and patty handling prior to cooking Pesh, thawed either as patties or bulk ground beef). Purchase location was not a statistically significant influence on cooking and color properties. Patties processed from bulk thawed product had a higher amount of brown cooked color. A strong relationship existed between visual and instrumental measures of red color in cooked patties. However, correlations among other cooking properties were low. Patties with higher fat content were associated with shorter cooking times, lower cooking yields and more brown cooked color. The low relationships between raw and cooked patty properties limits the use of raw ground beef properties as predictors of food safety in cooked beef patties. This further supports the use of instant read meat thermometers in cooking beef patties to at least 71C.