Fibers were produced from soy protein isolate by both wet-spinning and extrusion. In the wet-spinning process, aged, alkaline protein solution was forced through a spinnerette into an acid coagulating bath. In the extrusion process, a twinscrew extruder forced a protein isolate-water mixture through a die. The physical properties of the fibers were measured at various water activities. The fibers produced by both methods were brittle and lacked tensile strength (tenacity). The addition of glycerol reduced brittleness in extruded fibers. Zinc and calcium ions decreased the brittleness of wet-spun fibers. The tenacity of soy fibers was significantly improved by post-spinning treatments, including acetic anhydride, acetaldehyde, glyoxal, glutaraldehyde, a combination of glutaraldehyde and acetic anhydride, and stretching. The best extruded fibers were produced with a mixture of 45% soy protein, 15% glycerol, and 40% water, finished with a combination of glutaraldehyde and acetic anhydride and then stretched to 150% their original lengths. The best wet-spun fibers were produced with a 19.61% soy protein suspension at pH 12.1; coagulated in a 4% hydrochloric acid solution that contained 3.3% sodium chloride, 3.3% zinc chloride, and 3.3% calcium chloride; and followed by treatment with 25% glutaraldehyde and stretching to 1 70% their original lengths.
Soymilk made from lipoxygenase-free soybeans had less cooked beany aroma, less cooked beany flavor and less astringency and was rated darker and more yellow than that made from soybeans with normal lipoxygenase. Sensory descriptive panelists noted no differences between lipoxygenase-free and normal soybeans for milky flavor, wheat flavor, thickness, chalkiness or aftertaste. Tofu made from lipoxygenase-free soybeans had less cooked beany flavor than that made from normal soybeans. There were no differences in cooked beany aroma, raw beany aroma, raw beany flavor, wheat flavor, astringency, hardness, darkness or yellowness. Native-born Japanese, Chinese and U.S. descriptive panelists differed in responses to flavor, texture and color of soymilk and tofu.
Fresh 'Tristar' strawberries were irradiated with electron beam irradiation at 0, 1, and 2 kGy. Fruit firmness decreased as irradiation dose increased. Water-soluble pectin increased and oxalate-soluble pectin decreased at 0 and 1 day after 1 and 2 kGy irradiation. Fruit firmness correlated with oxalate-soluble pectin content. Total pectin and nonextractable pectin were not affected by irradiation. The oxalate-soluble pectin content and firmness of irradiated strawberries increased slightly at the beginning of 2ЊC storage and then decreased as storage time increased. No changes occurred in water-soluble pectin, nonextractable pectin, or total pectin during storage.
A descriptive analysis panel developed terms to describe aroma and flavor of soymilk. Panelists evaluated a commercial soymilk and soymilks processed with beans from the normal or lipoxygenase-free lines. Descriptors used to describe "beaniness" were "raw as hexanal" for flavor or aroma, "grassy" flavor, and "sweet as green floral" flavor. High correlations were found among these attributes. Judges were consistent in the use of terminology. "Beaniness" for the normal soymilk was described by the terms "raw aroma as in hexanal" and "raw flavor as in hexanal," while "beaniness" for soymilk from the lipoxygenase-free line was described by the terms "sweet as green floral" and "grassy" flavors.
Self-assessment allows learners to observe, analyze, and evaluate their own performances. Self-reflection allows the student to assess his or her communication skill level and progress against a standard. Additionally, the implementation of self-assessment through carefully prepared classroom experiences enables learners to manage their own learning and encourages the habit of lifelong learning. The objective of this study was to compare self-evaluation formats for assessment of an oral communication activity. Senior students in 2 sections of a 1-credit seminar course were videotaped while presenting 30-min oral presentations to the class. Students viewed their presentations and assessed their work using either a scoring rubric or a reflection assignment. Peer and instructor evaluations were also completed. Average scores by students and instructor were similar for rubric and reflection assessment methods. Oral evaluation scores by peer assessment were higher than by self-and instructor-assessment. Students were able to accurately describe the strengths and weaknesses of their presentations; however, comments from the reflection format were more thoughtful and provided more personal information in comparison to the scoring rubric. This study demonstrated the importance of reflective material such as student thoughts and feelings. Skills in reflective self-evaluation and documentation of their progress in oral communication will help students position themselves to develop their own academic and professional goals, provide feedback to instructors, and compile a record for future employers.
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