Minimizing the Negative Flavor Attributes and Evaluating Consumer Acceptance of Chocolate Fortified with Peanut Skin Extracts.

In recent years, there has been increased interest in antioxidant-rich products by consumers wanting to enhance the health benefits of their diet. Chocolate has been identified as a natural source of antioxidant compounds, which resulted in the development of polyphenol-enriched chocolate products that are now available commercially. This study investigated the use of phenolic compounds extracted from peanut skins as a novel antioxidant source for the enrichment of milk chocolate. The extracts were encapsulated with maltodextrin to lessen their bitterness. Antioxidant potential of the encapsulated peanut skin extracts was evaluated by the 2,2-diphenyl-1-picrylhydrazl radical quenching assay. Encapsulated peanut skins were found to have a corrected Trolox equivalency of 31.1 µmol/g of chocolate up to 0.8% (w/w). To produce a product with an antioxidant content similar to that of dark chocolate yet which maintained the milder flavor of milk chocolate, the best estimate threshold of encapsulated peanut skin extract in chocolate was 0.9 % (w/w) based on the standard method (American Society of Testing Materials; ASTM E-679). Consumer liking of milk chocolate enhanced by adding subthreshold (0.8 % (w/w)) inclusion levels of encapsulated peanut skin extract was found to be at parity with milk chocolate as a control.

The effect of refrigerated and frozen storage on butter flavor and texture.

Butter is often stored for extended periods of time; therefore, it is important for manufacturers to know the refrigerated and frozen shelf life. The objectives of this study were to characterize the effect of refrigerated and frozen storage on the sensory and physical characteristics of butter. Fresh butter was obtained on 2 occasions from 2 facilities in 113-g sticks and 4-kg bulk blocks (2 facilities, 2 package forms). Butters were placed into both frozen (-20 degrees C) and refrigerated storage (5 degrees C). Frozen butters were sampled after 0, 6, 12, 15, and 24 mo; refrigerated butters were sampled after 0, 3, 6, 9, 12, 15, and 18 mo. Every 3 mo, oxidative stability index (OSI) and descriptive sensory analysis (texture, flavor, and color) were conducted. Every 6 mo, peroxide value (PV), free fatty acid value (FFV), fatty acid profiling, vane, instrumental color, and oil turbidity were examined. A mixed-model ANOVA was conducted to characterize the effects of storage time, temperature, and package type. Storage time, temperature, and package type affected butter flavor, OSI, PV, and FFV. Refrigerated butter quarters exhibited refrigerator/stale off-flavors concurrent with increased levels of oxidation (lower oxidative stability and higher PV and FFV) within 6 mo of refrigerated storage, and similar trends were observed for refrigerated bulk butter after 9 mo. Off-flavors were not evident in frozen butters until 12 or 18 mo for quarters and bulk butters, respectively. Off-flavors in frozen butters were not correlated with instrumental oxidation measurements. Because butter is such a desirable fat source in terms of flavor and textural properties, it is important that manufacturers understand how long their product can be stored before negative attributes develop.

Phenolic acid content and composition in leaves and roots of common commercial sweetpotato (Ipomea batatas L.) cultivars in the United States.

Phenolic acids in commercially important sweet potato cultivars grown in the United States were analyzed using reversed-phase high-performance liquid chromatography (HPLC). Caffeic acid, chlorogenic acid, 4,5-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 3,4-di-O-caffeoylquinic acid were well separated with an isocratic elution in less than 25 min compared to about 120 min for analyzing and re-equilibrating the column with a gradient method. The isocratic elution order of these caffeoylquinic acid derivatives was confirmed by LC-MS/MS. Chlorogenic acid was the highest in root tissues, while 3,5-di-O-caffeoylquinic acid and/or 4,5-di-O-caffeoylquinic acid were predominant in the leaves. Steam cooking resulted in statistically nonsignificant increases in the concentration of total phenolics and all the individual phenolic acids identified. Sweetpotato leaves had the highest phenolic acid content followed by the peel, whole root, and flesh tissues. However, there was no significant difference in the total phenolic content and antioxidant activity between purees made from the whole and peeled sweet potatoes.

Chemical properties and consumer perception of fluid milk from conventional and pasture-based production systems.

The continued popularity of organic and natural foods has generated interest in organic milk, and use of pasture for dairy cattle is a requirement for organic production. This process may improve the health benefits of fluid milk via increases in the unsaturated fatty acid content, including conjugated linoleic acid. Because pasture-based (PB) systems vary in types of forage, it is important to understand the impact of feed on the composition and flavor of fluid milk. The objectives of this study were to compare the chemical and sensory properties of PB milk with conventional fluid milk from Jersey and Holstein cows and to evaluate consumer acceptance of those milks. Fluid milk was collected throughout the 2006 growing season from Holstein and Jersey cows located in 2 herds: one fed a PB diet and one fed a conventional total mixed ration (TMR) diet. Milk was batch-pasteurized and homogenized. Sensory analyses, descriptive profiling, difference testing, and consumer testing were conducted on pasteurized products in separate sessions. Instrumental volatile analysis and fatty acid composition profiling were also conducted. The instrumental and sensory analyses differentiated the PB and TMR milks. Greater percentages of unsaturated fatty acids, including 2 common isomers of conjugated linoleic acid, were measured in PB milks. Trained panelists documented greater intensities of grassy and cowy/barny flavors in PB milks compared with TMR milks when evaluated at 15 degrees C. Volatile compound analysis by solid-phase microextraction and gas chromatography-mass spectrometry separated PB and TMR milk samples. However, analyses showed no compounds unique to either sample. All identified compounds were common to both samples. Consumers were unable to consistently differentiate between PB and TMR milks when evaluated at 7 degrees C, and cow diet had no effect on overall consumer acceptance. These results indicate distinct flavor and compositional differences between TMR and PB milks, but the differences were such that they did not affect consumer acceptance. The current findings are useful to consider as interest in PB dairy production systems grows.

Association between exercise and HIV disease progression in a cohort of homosexual men.

PURPOSE: To study the relationship between exercise and human immunodeficiency virus (HIV) disease progression. METHODS: 415 individuals (156 HIV positive, 259 HIV negative), from a cohort study of 851 homosexual men from New York City, 1985-1991. By 1991, 68 of the 156 persons developed Acquired Immune Deficiency Syndrome (AIDS) and 49 died with AIDS. Exercise was defined as self-report of exercising 3-4 times/week or daily at entry; less was considered nonexercise. CD4 lymphocyte decline was constructed for each subject by modeling log CD4 count against time in days. The association between exercise and progression to AIDS and death with AIDS, adjusting for baseline CD4 count, was determined using Cox model. Linear regression was used to model CD4 decline with exercise for HIV positive and HIV negative groups separately, adjusting for initial CD4 count. RESULTS: Having exercised was associated with slower progression to AIDS at 1 year (HR = 0.68, 90% confidence interval (CI): 0.4-1.17); hazard ratios (HR) at 2, 3, and 4 years were 0.96, 1.18, and 1.36, respectively. Having exercised was also associated with slower progression to death with AIDS at 1 year (HR = 0.37, 90% CI: 0.14-0.94) with hazard ratios at 2, 3, and 4 years of 0.68, 0.98, and 1.27, respectively, suggesting a protective effect close to the time exercise was assessed, but an increased risk after 2 years. Exercising 3-4 times/week had a more protective effect than daily exercise. Exercisers in the HIV positive group showed an increase in CD4 count during a year by a factor of 1.07. CONCLUSION: Moderate physical activity may slow HIV disease progression.

Electrophoretic patterns of protein synthesis and turnover in apical plasma membrane and outer bilayer of Schistosoma mansoni.

Polypeptide fractions labelled with [14C]leucine and associated with fractionated inner plasma membrane and outer bilayer (envelope) from the apical double bilayer complex of the surface epithelium of the human blood fluke, Schistosoma mansoni, were analyzed by two-dimensional electrophoresis and fluorography. In contrast to the distribution of alkaline phosphatase, the polypeptide profiles of the two bilayer fractions were similar due to cross contamination between one membrane containing larger amounts of protein (inner) and the second bilayer having more heavily labelled proteins (outer bilayer). Convincing evidence for only two of 35 polypeptides could be provided for localization to the outer bilayer. These results suggest that the marker enzyme used for the inner bilayer, alkaline phosphatase, may not be homogeneously distributed in this membrane. In pulse-chase studies a correction factor for cross-contamination was derived. The rate of turnover of the polypeptide fractions was twice as fast for the outer compared to the inner membrane, this difference being consistent with the view that multilamellar bodies are the precursors of the apical double bilayer complex. Comparing the rates of surface renewal in adult and juvenile schistosomes leads to the suggestion that membrane turnover can be correlated with susceptibility to host immune effector mechanisms.

Sequential removal of outer bilayer and apical plasma membrane from the surface epithelial syncytium of Schistosoma mansoni.

The outer and inner bilayers of the apical membrane complex of Schistosoma mansoni were sequentially stripped from adult worms by two incubations in 0.1% digitonin solutions. Membrane removal was evaluated by electron microscopy of worms and bilayer material, using Con A-ferritin as a marker for the outer bilayer. Amounts of Con A removed by the digests were measured with a tritiated Con A marker. To measure the purity of the fractions membrane markers were characterised and quantitated for both bilayers. In the absence of the usual enzymatic markers for plasma membrane diazotised [125I]-iodosulfanilic acid was used as a marker for the outer bilayer. Alkaline phosphatase and a Na+, Mg2+-ATPase were localised to the inner bilayer. From these results we can deduce that the inner bilayer is analogous to the typical, apical plasma membrane of other animal epithelia. The outer bilayer does not share these enzymatic similarities. The integrity of the syncytium after removal of the outer bilayer and the increased levels of lactate dehydrogenase in the supernatant after removal of the inner bilayer suggests that the outer bilayer is secondary in maintaining the permeability barrier of the apical membrane complex, with respect to soluble proteins. The possible significance of these results in terms of the destructive action of complement on the parasite are discussed.

A method for determining nonelectrolyte uptake by adult schistosoma mansoni using compartmental analysis of hexose fluxes.

A steady-state compartmental analysis of galactose, glucose and 3-O-methylglucose fluxes was conducted on male and female Schistosoma mansoni. The method has several advantages over previously used initial rate studies. A nonlinear log-linear plot of glucose exchange is discussed in terms of differentiating between metabolized and nonmetabolized substrates in transport studies. Kt values and marker distribution volumes are estimated from the compartmental analysis and it is concluded that 3-O-methylglucose is not suited as a substrate for hexose transport studies in S. mansoni.

Uptake of galactose by the epithelial syncytium of Schistosoma mansoni.

A steady-state compartmental analytical solution to radiolabeled galactose fluxes into and out of S. mansoni using a three compartment model is presented. Experiments included phlorizin inhibition, Na+-free incubations and inhibition experiments with glucose and 3-O-methylglucose. The inward rate constants exceeded the outward exchange rates by a factor of 1.55 in females and 1.85 in males. Phlorizin, Na+-free conditions and the other hexoses reduced the inward exchange rates such that net secretion of galactose would be favored since the inward to outward exchange rates were less than unity. In the Na+-free incubations, the outward exchange rate was increased but not in the other experiments. The steady-state Kt values were increased in Na+-free incubations and during inhibitions by glucose and 3-O-methylglucose, but not in response to phlorizin. The size of the exchangeable tissue pool of galactose was decreased in a predictable manner when the exchange rates across the surface epithelial syncytium were reduced by glucose, 3-O-methylglucose, phlorizin and Na+-free incubations. The results were generally consistent with previous findings of stereospecific Na+-coupled uptake of galactose by S. mansoni.

The human element in survey research.

This paper addresses itself to issues related to data collection in survey research with a community population. Areas discussed related to practical human problems in conducting a community survey of a stratified random sample of people sixty-five years of age and over in New York City. Some of these problems occur in most large scale community surveys, but some are a result of special features of this particular study. Topics covered include difficulties encountered in obtaining interviews, maintaining the staff, and coordinating the research team in the ongoing U.S.-U.K. Cross-National Project.