Screening Potato Starch for Novel Properties Using Differential Scanning Calorimetry

Thermal and other physicochemical properties of starch from 42 potato genotypes were studied to find those with unique properties for food use, and to analyze relationships between thermal and other physicochemical properties. Onset and peak transition temperatures and gelatinization enthalpy intercorrelated. Transition temperatures intercorrelated with pasting temperature using a Brabender Visco-amylograph. Gelatinization entbalpy correlated with Brabender pasting temperature and peak paste viscosity, and onset temperature correlated with phosphorus content. Genotype E55–3.5 with highest onset and peak transition temperatures also had highest phosphorus and peak Brabender viscosity. DSC might be useful for rapidly screening samples of <1g starch for such. Potato starch DSC characteristics did not correlate with amylose, intrinsic viscosity, or water-binding. For 10 genotypes from successive years, correlations were observed for pasting temperature (r = 0.83), phosphorus content (r = 0.80), and stability ratio (r = 0.66). Direct comparison between samples from consecutive years showed good reproducibility for amylose, but not for phosphorus or pasting.     

Integrating Communication and Engineering Education: A Look at Curricula,Courses, and Support Systems

In this article we point to the ways in which engineering and communication disciplines can work together to ensure the ABET criterion that encompasses effective communication is represented in engineering curricula. Drawing upon examples from several universities in North America, we offer useful portraits of writing across the curriculum approaches, interdisciplinary courses, integrated programs, and a variety of support systems including writing and communication centers and online resources. As we develop increased awareness of the importance of including communication instruction in engineering curricula, the variety of possibilities presented in this article can help us integrate communication and engineering education.     

EDITORIAL

Rangia clam, an abundant under utilized mollusc found in southeastern coastal waters, has successfully met shellfish microbial requirements through relaying or depuration. A problem encountered in developing Rangia into a viable seafood resource has been the occasional presence of an objectionable “muddy” flavor. The purpose of this study was to identify the high quality harvesting months when the muddy flavor was absent or minimal and to evaluate muddy flavor and acceptability of the clam when used in value-added processed products. Steamed clams were evaluated at harvest every month for 1 year, and at 1 and 2-weeks’ iced storage for “muddy” flavor and acceptability by a 10-member trained sensory panel. Rangia value-added products were similarly evaluated. Muddy flavor, found to be lowest in the colder winter months, was inversely correlated with acceptability (R²= 0.73). Flavor scores were consistent throughout 2-weeks of iced storage. Value-added products were rated very low in muddy flavor and very high in acceptability.     

KINETIC STUDY OF T-2 TOXIN METABOLITES IN A COW

A Holstein cow was given a single, oral dose of T-2 toxin (200 mg), and blood and urine samples were collected at regular time intervals for 48 h. The animal was dosed once more with the same amount and samples were again collected over another 48 h period. Trace amount (2 ppb) of T-2 toxin was detected in the blood up to 24 h as well HT-2, TC-3, and T-2 tetraol. De-epoxy-T-2-tetraol was detected in the blood and urine up to 48 h. No T-2 could be found in the urine but HT-2, TC-1, TC-3 and T-2-tetraol were detected. In addition, three major metabolites, i.e., iso TC-1, de-epoxy-TC-3 and de-epoxy-T-2 tetraol, were found in the urine. Production of these metabolites was maximum at 14–20 h after administration of the toxin. No substantial accumulation of T-2 toxin derivatives were found in the lung, heart, liver or kidney when the cow was sacrificed at the end of the experiment.     

Effect of Environmental Salinity on Sensory Characteristics of Penaeid Shrimp

White shrimp, Penaeus vannamei, acclimated to 10, 30 and 50 parts per thousand (ppt) salinities were evaluated for flavor by a trained sensory panel. The shrimp were also analyzed for tissue moisture, chloride, free amino acid concentration and free amino acid profile. Results of triangle tests showed a significant flavor difference between shrimp held at 10 and 50 ppt and 30 and 50 ppt but not between 10 and 30 ppt. On a wet weight basis, the free amino acid concentration was 81% higher in shrimp held at 50 ppt than at 10 ppt and 63% higher in shrimp held at 50 as compared to 30 ppt. However, between shrimp held at 30 as compared to 10 ppt the difference was only 11%. The difference in flavor intensity of shrimp held at different salinities appeared to be a direct reflection of the concentration of tissue free amino acids which serve as osmoregulators in shrimp tissue.     

Effects of Ultrafiltration on Retention of Minerals and Other Components of Milk

Retentions of milk components were determined following laboratory-scale ultrafiltration using membranes of different composition and molecular weight cut-offs, milks at different stages of processing, and concentration factors of 2.0x and 1.5x. Component retentions were not affected by membrane composition, molecular weight cut-off, pasteurization or homogenization. Whole milk showed a higher percent recovery of total solids than skim milk. Pasteurized, homogenized whole milk concentrated 1.5x retained more total solids than when concentrated 2.0x, although mineral retentions were not appreciably affected. There was virtually complete retention of protein (93–100%) in all milks, while the transfer of lactose through the membranes was similar to that of water. Mineral retentions varied little from milk to milk and 2.0x retentates had individual recoveries of 16 different minerals ranging from approximately 50% to over 90%.