Cholesterol and Antioxidant Vitamins in Fat Fraction of Whole and Skimmed Dairy Products

The skimming procedure is a common practice in dairy industry, and skimmed products contain less fat, less cholesterol and less fat-soluble vitamins than whole products. The aim of this research is to verify if something else happens during the skimming process to these compounds in milk and dairy products. Experimental milk and cream samples, ranging from 0.1 to 51.5 g fat/100 g, have been studied for beta carotene, alfa-tocopherol and cholesterol contents. The degree of antioxidant protection (DAP), useful to estimate the potential oxidative stability of fat in foods, has been calculated, combining these values. The same analytical protocol has been also applied to commercial products (fat content ranging from 0.1 to 85.0 g/100 g). As was expected, there is a good linear correlation between these compounds and fat content in experimental and in commercial samples; nevertheless, the composition of milk fat changes differently. During skimming process, in the residual fat matter, cholesterol concentration increases while antioxidant compound concentration decreases or remains unchanged. Moreover, in experimental and in commercial milk and dairy, the DAP values show that the residual cholesterol is more susceptible to oxidation in skimmed than in whole products. This aspect is particularly important from a safety point of view: actually, cholesterol oxide ingestion can be harmful and should be avoided even in a small amount.     

Bacterial contamination of cucumber fruit through adhesion

In this study, the adhesion of bacteria to fresh cucumber surfaces in aqueous suspension was shown to be dependent on time of incubation, inoculum species and concentration, and temperature. The adhesion of bacteria to the fruit in wash water was less extensive at lower temperatures and shorter exposure times. Various species of bacteria were adsorbed to cucumber surfaces in the following relative order: Salmonella Typhimurium > Staphylococcus aureus > Lactobacillus plantarum > Listeria monocytogenes. Cells were adsorbed at all temperatures tested (5, 15, 25, and 35 degrees C) at levels that depended on incubation time, but the numbers of cells adsorbed were larger at higher incubation temperatures. Levels of adhesion of bacteria to dewaxed fruit were higher for L. monocytogenes and lower for Salmonella Typhimurium, L. plantarum, and S. aureus than were levels of adhesion to waxed fruit.     

Some interrelated thermophysical properties of liquid water and ice. I. A user-friendly modeling review for food high-pressure processing

A bibliographic search yielded a set of empirical equations that constitute an easy method for the calculation of some thermophysical properties of both liquid water and ice I, properties that are involved in the modeling of thermal processes in the high-pressure domain, as required in the design of new high-pressure food processes. These properties, closely interrelated in their physical derivation and experimental measurement, are specific volume, specific isobaric heat capacity, thermal expansion coefficient, and isothermal compressibility coefficient. Where no single equation was found, an alternative method for calculation is proposed. Keeping in mind the intended applications and considering the availability of both experimental data and empirical equations, the limits for the set of equations where set in -40 to 120 degrees C and 0 to 500 MPa for liquid water and -30 to 0 degrees C and 0 to 210 MPa for ice I. The equations and methods selected for each property are described and their results analyzed. Their good agreement with many existing experimental data is discussed. In addition, the routines implemented for the calculation of these properties after the described equations are made available in the public domain.     

The ORF YNL274c (GOR1) codes for glyoxylate reductase in Saccharomyces cerevisiae

The enzyme glyoxylate reductase reversibly reduces glyoxylate to glycolate, or alternatively hydroxypyruvate to D-glycerate, using either NADPH or NADH as a co-factor. The enzyme has multiple metabolic roles in different organisms. In this paper we show that GOR1 (ORF YNL274c) encodes a glyoxylate reductase and not a hydroxyisocaproate dehydrogenase in Saccharomyces cerevisiae, even though it also has minor activity on alpha-ketoisocaproate. In addition, we show that deletion of the glyoxylate reductase-encoding gene leads to higher biomass concentration after diauxic shift.     

Self-help cessation programs for smokeless tobacco users: long-term follow-up of a randomized trial.

This paper presents long-term outcomes of the largest clinical trial of smokeless tobacco (SLT) cessation reported to date. SLT users in five northwestern states were recruited to call a toll-free number, and 1,069 users were randomized to one of two self-help conditions: either a manual-only condition or an assisted self-help condition, which included the manual, a targeted video, and two support phone calls. Significant between-group differences were not found for either the 12- or 18-month point-prevalence measure of abstinence from either SLT only or all tobacco products using outcomes based on either the responder or intention-to-treat outcomes. However, using a repeated point-prevalence measure across all three assessment points, we found that significantly more assisted self-help participants reported abstinence, compared with manual-only participants. Compared with manual-only participants, those in the assisted self-help condition were significantly more likely to use recommended cessation techniques. Results demonstrate that low-cost, minimal interventions delivered by mail and phone can help a sizable proportion of individuals quit using SLT.     

Bioaccumulation of perfluorochemicals in sediments by the aquatic oligochaete Lumbriculus variegatus

Bioaccumulation of perfluoroalkyl sulfonates, perfluorocarboxylates, and 2-(N-ethylperfluorooctane sulfonamido) acetic acid (N-EtFOSAA) from laboratory-spiked and contaminated field sediments was assessed using the freshwater oligochaete, Lumbriculus variegatus. Semistatic batch experiments were conducted to monitor the biological uptake of these perfluorochemicals (PFCs) over 56 days. The elimination of PFCs was measured as the loss of PFCs in L. variegatus exposed to PFC-spiked sediment for 28 days and then transferred to clean sediment. The resultant data suggest that PFCs in sediments are readily bioavailable and that bioaccumulation from sediments does not continually increase with increasing perfluorocarbon chain length. Perfluorooctane sulfonate (PFOS) and perfluorononanoate were the most bioaccumulative PFCs, as measured by laboratory-based estimated steady-state biota sediment accumulation factors (BSAFs) and BSAFs measured using contaminated field sediments. Elimination rate constants for perfluoroalkyl sulfonates and perfluorocaroboxylates were generally smaller than those previously measured for other organic contaminants. Last, a PFOS precursor, N-EtFOSAA, accumulated in the worm tissues and appeared to undergo biotransformation to PFOS and other PFOS precursors. This suggests that N-EtFOSAA, which has been detected in sediments and sludge often at levels exceeding PFOS, may contribute to the bioaccumulation of PFOS in aquatic organisms.