Stereological estimation of surface area and barrier thickness of fish gills in vertical sections

Previous morphometric methods for estimation of the volume of components, surface area and thickness of the diffusion barrier in fish gills have taken advantage of the highly ordered structure of these organs for sampling and surface area estimations, whereas the thickness of the diffusion barrier has been measured orthogonally on perpendicularly sectioned material at subjectively selected sites. Although intuitively logical, these procedures do not have a demonstrated mathematical basis, do not involve random sampling and measurement techniques, and are not applicable to the gills of all fish. The present stereological methods apply the principles of surface area estimation in vertical uniform random sections to the gills of the Brazilian teleost Arapaima gigas. The tissue was taken from the entire gill apparatus of the right‐hand or left‐hand side (selected at random) of the fish by systematic random sampling and embedded in glycol methacrylate for light microscopy. Arches from the other side were embedded in Epoxy resin. Reference volume was estimated by the Cavalieri method in the same vertical sections that were used for surface density and volume density measurements. The harmonic mean barrier thickness of the water‐blood diffusion barrier was calculated from measurements taken along randomly selected orientation lines that were sine‐weighted relative to the vertical axis. The values thus obtained for the anatomical diffusion factor (surface area divided by barrier thickness) compare favourably with those obtained for other sluggish fish using existing methods.     

Probiotic buttermilk-like fermented milk product development in a semiindustrial scale: Physicochemical, microbiological and sensory acceptability

Probiotic buttermilk-like fermented milk in different flavors in versions with sucrose and sucralose were processed in a pilot plant. The Mesophilic Aromatic Culture CHN-22 and Bifidobacterium animalis Bb12 were the cultures employed for fermentation. Physicochemical composition, apparent viscosity, diacetyl content, viability of cultures during storage, and acceptance of product via sensorial analysis were assessment factors. The high viability of the probiotic culture was observed (average 8.08 log cfu/ml) during refrigerated storage (28 days) of buttermilk and good acceptance of the product via sensory test. However, the probiotic culture might have been responsible for the loss of diacetyl, a volatile compound that is a characteristic feature of the product.     

PRESTORAGE MOISTURE CONTENT AFFECTS COLOR LOSS OF GROUND PAPRIKA (Capsicum annuum L.) UNDER STORAGE

Ground paprika samples from cultivars ‘B-18’; and ‘NuMex Sweet’; were adjusted to different prestorage moisture contents and stored under ambient temperature (19C–24C) and humidity (24–42%). Moisture content, water activity, extractable color, and surface color were determined before storage and then monthly for four months. Prestorage moisture contents equilibrated during storage. At the end of the storage period all samples had about 10% moisture content. Samples with 6% or 9% prestorage moisture content had 92% and 90% extractable color loss, respectively, for ‘B-18’; paprika and 84% and 83% color loss for ‘NuMex Sweet’; paprika, respectively. In contrast, samples stored at higher moisture contents had less color loss. Color loss after four months storage was 53% and 32% for ‘B-18’; and 51% and 30% for ‘NuMex Sweet’; at 15% and 18% prestorage moisture contents, respectively. Surface color was also affected by moisture content.     

PROLONGING THE SHELF-LIFE OF FRESH GREEN CHILE PEPPERS THROUGH MODIFIED ATMOSPHERE PACKAGING AND LOW TEMPERATURE STORAGE

The postharvest quality of green chile fruit was compared after storage in 3 types of packages at 2 temperatures (24C and 8C). Package types were corrugated cardboard boxes, pressed cardboard trays overwrapped with VF-71 polyethylene, or low-density polyethylene (LDPE) bags. Fruit packaged in boxes or overwrapped trays had 24.8% and 10.1% weight loss, respectively, after 1 week of storage at 24C. Fruit packaged in polyethylene bags lost 0.3% weight and remained green. After 1 week at 8C, the weight losses were 3.8%, 1.8% and 0% for the boxed, overwrapped and bagged treatments, respectively. Postharvest quality was maintained up to 4 weeks when fruit were packaged in LDPE bags and stored at 8C. In a second study, steady state O₂ and CO₂ levels were determined inside the LDPE packages as fruit weight and temperature were varied. Storage temperatures were 24C, 16C and 8C. At 8C, steady state O₂ levels ranged from 12.0 kPa to 0.9 kPa, and CO₂ levels ranged from 2.0 kPa to 4.6 kPa as fruit weight was increased from 120 to 480 g. At 24C and 16C, fruit packaged in 480 g units had slower ripening rates than fruit packaged in smaller units; however, fruit stored at 8C remained green the longest, regardless of fruit weight.     

EFFECT OF GAMMA IRRADIATION ON SOFTENING CHANGES AND ENZYME ACTIVITIES DURING RIPENING OF PAPAYA FRUIT

The aim of this work was to study the role of cell wall and ethylene related enzymes to papaya fruit firmness. Irradiation treatment was used as an imposed stress to cause changes in firmness. Physiologically mature papaya fruits were irradiated (500 Gy) and allowed to ripen at 22C and 90% RH. Polygalacturo‐nase (PG), pectinmethylesterase (PME), βgalactosidase, cellulose and 1‐aminocyclopropane‐1‐carboxylate oxidase (ACC‐oxidase) activities were followed during ripening and correlated to changes in firmness, skin and pulp color, respiration and ethylene production. The firmness of irradiated fruits was retained at least 2 days longer than in normal fruits and also had a slower rate of softening. Total soluble solids (d?Brix), cellulase activity and ethylene production were not altered by irradiation treatment. The activity patterns of PG, PME and β‐galactosidase were related to pulp softening and affected by irradiation. ACC‐oxidase activity was influenced by irradiation treatment, but its changes were not temporally related to those in firmness. It was concluded that irradiation had no direct effect on firmness but it acted by altering the ripening induced synthesis of cell wall enzymes, mainly PME.     

ETHICS MATTER: THE MORALITY AND JUSTICE PRINCIPLES OF ELECTED CITY OFFICIALS AND THEIR IMPACT ON URBAN ISSUES

ABSTRACT: This article pursues the thesis that ethics matter in urban policymaking. Interviews with 95 elected officials in 12 cities revealed the officials' support for—and opposition to—many principles of political morality and political justice. Officials regarded their ethical principles as almost as important as economic constraints on their policy decisions, and much more important than political, legal, jurisdictional, and cultural considerations. The role of ethics in the resolution of 93 issues that arose in their communities varied from minimal to decisive. On some occasions ethical considerations served mainly as justifications for policy decisions made primarily on other grounds. But more often, significant numbers of officials drew largely, and even primarily, on their own moral judgments when casting their votes on community issues. And some policies were driven by consensual moral understandings.     

A CHOLESTEROL AND SUCROSE RICH DIET PROMOTES LIPOPROTEIN PEROXIDATION AND IMPAIRS INSULIN SENSITIVITY IN RATS

The effects of a diet rich in cholesterol and sucrose on lipoprotein peroxidation and insulin sensitivity were studied in rats. The protective role of fish oil dietary supplementation, both alone and associated with antioxidants, was also investigated. Four groups of 6 male rats were treated for 4 weeks with a standard diet, rich in cholesterol and sucrose (atherogenic diet), atherogenic diet plus fish oil and atherogenic diet plus fish oil enriched in polycosanols, terpenes and antioxidants. Atherogenic diet induced a significant increase in plasma concentration of cholesterol, triglycerides, free fatty acids and atherogenic index; moreover, it significantly enhanced the susceptibility of lipoproteins to peroxidation and the resistance to insulin. Dietary integration with fish oil limited the development of the above risk factors, the association with polycosanols, terpenes and antioxidants being more efficacious than fish oil alone.     

Politics of the Light Object: Transformative Architectural Installations

The research, built work and design seminar entitled "The Politics of the Object: Transformative Public and Cultural Landscapes" examined the critical history of a 150-year old open air market in a dense urban area of Hong Kong. This culminated in a series of built installations that used light as a critical design medium to engage the public on urban renewal issues and questions of rapid development in Hong Kong. This ongoing educational initiative aimed to encourage debate about the issues of planned development and the neighborhood's preservation of cultural values.     

RESIDUAL PECTINESTERASE ACTIVITY IN DEHYDRATED ONION AND GARLIC PRODUCTS

During the dehydration of onion and garlic products, use of high temperatures is undesirable due to the potential loss of aroma and flavor characteristics. As a consequence, residual pectinesterase (PE) activity may be found in these dehydrated spices. This study reports the presence of PE activity in raw onions and in dehydrated onion and garlic products. Pectinesterase activity is higher in the raw onion stem disks, and dehydrated products made from this tissue, than in the bulbs. Dehydrated onion products induced gelation of citrus pectin solutions and tomato purees. Although some inactivation of PE in dehydrated onion water suspensions and extracts was observed after 10 min at 50C, complete inactivation required 2 min at 82C. Commercial dehydration operations may require reevaluation to eliminate residual PE activity in dehydrated onion and garlic products.     

Natural Antioxidants for Preventing Color Loss in Stored Paprika

Oxidative carotenoid degradation causes paprika color loss during storage. Ethoxyquin, a synthetic antioxidant, is used in the spice industry to prevent carotenoid loss during postharvest handling. However, ethoxyquin treated paprika is unacceptable for some markets and consumers. Naturally derived antioxidants, i.e., rosemary extracts, ascorbic acid, δ-tocopherol, and mixed tocopherols were tested as color protectants in two paprika cultivars. Extractable color, surface color and carotenoid concentrations were determined before storage and then monthly. After 4 mo storage at ambient temperature, the control treatment lost 63% of the initial extractable color, the δ-tocopherol treated samples lost 32%, and the ethoxyquin lost 6% color.