Phase Transitions and Functionality of Enzymes and Yeasts in Dehydrated Matrices

Enzymes and yeast cells were chosen as model probes to investigate functional changes taking place in freeze-dried systems containing different sugars, polymers and salts undergoing phase/state transitions. Differential scanning calorimetry, X-rays diffraction and microscopy provided information on molecular and microscopic changes. Enzyme stability depended on the amorphous structure and non-reducing characteristics of sugars, and residual activity was very low in the super-cooled region when sugars crystallised. The addition of polymers or salts extended the protective effect of sugars to the super-cooled region by delaying crystallisation. Starch provided adequate protection to the enzyme at high water content and low temperatures, where stability was completely lost in other systems. The presence of low-molecular-weight saccharides during drying and storage appeared to be the critical factor protecting cell viability. State diagrams are helpful to analyse the combined effects of temperature, water content and physical state on the stability of biomaterials but there is no direct relationship between overall physical properties and the kinetics of deteriorative changes. Additional information on molecular interactions is relevant to define strategies to preserve the functionality of biomolecules.

Note: Relationships of Consumer Acceptability and Sensory Attributes of Yerba Mate (Ilex Paraguariensis St. Hilarie) using Preference Mapping

A sensory profile and acceptability test of nine commercial brands of yerba mate (Ilex paraguariensis St. Hilarie) were carried out. The descriptors used by a trained sensory panel that best separated brands were: stick and leaf size, stick and leaf size uniformity, quantity ofsticks and quantity of dust, included in the appearance of the dry yerba; sediment, turbidity and brown colour that corresponded to appearance of the infusion; and initial impact, acid, humid, smoke, paper, chemical, green, toasted and residual, for aroma and flavour. A total of 106 consumers (half men, half women) tested overall acceptance of the 9 brands in a home location test. Average overall acceptance scores for the 9 samples ranged from 42 to 63 on a 0–100 non-structured scale with an LSD of 8. Gender did not influence consumer acceptability forthe different yerba mate brands. Based on overall acceptance consumers were clustered into five groups. Extended internal preference mapping showed the descriptors of yerba mate that drovethe preference of some of the consumers clusters. Both appearance and aroma/flavour descriptors were correlated to preference dimensions.

Influence of various traditional seasonings on beef flavor: United States, Spanish, and Argentinian practices

A consumer study was conducted to determine the most popular beef seasonings used in three countries: Argentina, United States (US), and Spain. Once the typical cooking methods and seasonings in these countries were established, descriptive analysis was used to determine the differences in the main flavor attributes, particularly the impact on beef characteristics, of the samples. Large variations were found in the consumer practices in the studied countries, and the preferred seasonings from each country were identified. This study showed that on average US consumers would prefer beef products with more initial flavor impact, brown/roasted and salty characteristics than Argentinian or Spanish consumers. The addition of seasonings changed some of the main beef attributes, but the changes were dependent on the cooking method. Beef identity (Beef ID), brown/roasted, and bloody/serumy were the attributes most affected when adding different seasonings.

Sensory Shelf Life of Dulce de Leche

The objectives of this research were to determine the sensory cutoff points for dulce de leche (DL) critical descriptors, both for defective off-flavors and for storage changes in desirable attributes, and to estimate the shelf life of DL as a function of storage temperature. The critical descriptors used to determine the cutoff points were plastic flavor, burnt flavor, dark color, and spreadability. Linear correlations between sensory acceptability and trained panel scores were used to determine the sensory failure cutoff point for each descriptor. To estimate shelf life, DL samples were stored at 25, 37, and 45 degrees C. Plastic flavor was the first descriptor to reach its cutoff point at 25 degrees C and was used for shelf-life calculations. Plastic flavor vs. storage time followed zero-order reaction rate. Shelf-life estimations at different temperatures were 109 d at 25 degrees C, 53 d at 37 degrees C, and 9 d at 45 degrees C. The activation energy, necessary to calculate shelf lives at different temperatures, was 14,370 +/- 2080 cal/mol.

Consumer acceptability versus trained sensory panel scores of powdered milk shelf-life defects

The objective of the present work was to correlate consumer panel acceptability versus trained sensory panel scores for appearance and flavor defects likely to appear during storage of whole milk powder. Descriptors selected for the study were: acid, caramel, cooked, dark color, lipolysis, and oxidized. For each descriptor a set of nine samples with different intensities were measured for acceptability and likelihood to consume by a 50-member consumer panel and for sensory intensity by a trained panel. Linear correlations between sensory acceptability and trained sensory panel scores were used to determine the sensory failure cut-off point for each descriptor, except caramel and cooked, which were not critical from the consumer's point of view. Differences in acceptability were found between Argentine and Uruguayan consumers for oxidized samples, while for lipolysis flavor, Argentine and Costa Rican consumers behaved similarly. For the color descriptor, significant changes in acceptability measured on a hedonic scale did not mean that consumers refused to consume the product. In contrast, for flavor descriptors, as soon as a significant decrease in acceptability occurred approximately 30% of the consumers said they would not consume the product. The sensory failure cut-off points presented in this paper can be used as a guide in future studies on the shelf life of MP and can also be of value in establishing sensory specifications for quality control programs. The methodology of correlating consumer acceptability to sensory panel scores and, thus, defining sensory failure is an improvement over more arbitrary criteria presented in most shelf-life studies.

Oxygenated carotenoid lutein and progression of early atherosclerosis: the Los Angeles atherosclerosis study

BACKGROUND

Carotenoids are hypothesized to explain some of the protective effects of fruit and vegetable intake on risk of cardiovascular disease. The present study assessed the protective effects of the oxygenated carotenoid lutein against early atherosclerosis.

METHODS AND RESULTS

EPIDEMIOLOGY

Progression of intima-media thickness (IMT) of the common carotid arteries over 18 months was determined ultrasonographically and was related to plasma lutein among a randomly sampled cohort of utility employees age 40 to 60 years (n=480). Coculture: The impact of lutein on monocyte response to artery wall cell modification of LDL was assessed in vitro by quantification of monocyte migration in a coculture model of human intima. Mouse models: The impact of lutein supplementation on atherosclerotic lesion formation was assessed in vivo by assigning apoE-null mice to chow or chow plus lutein (0.2% by weight) and LDL receptor-null mice to Western diet or Western diet plus lutein. IMT progression declined with increasing quintile of plasma lutein (P for trend=0.007, age-adjusted; P=0.0007, multivariate). Covariate-adjusted IMT progression (mean+/-SEM) was 0.021+/-0.005 mm in the lowest quintile of plasma lutein, whereas progression was blocked in the highest quintile (0.004+/-0.005 mm; P=0.01). In the coculture, pretreatment of cells with lutein inhibited LDL-induced migration in a dose-dependent manner (P<0.05). Finally, in the mouse models, lutein supplementation reduced lesion size 44% in apoE-null mice (P=0.009) and 43% in LDL receptor-null mice (P=0.02).

CONCLUSIONS

These epidemiological, in vitro, and mouse model findings support the hypothesis that increased dietary intake of lutein is protective against the development of early atherosclerosis.

Mitogen-activated protein kinase phosphatase 1 activity is necessary for oxidized phospholipids to induce monocyte chemotactic activity in human aortic endothelial cells

Entrapment and oxidation of low density lipoproteins (LDL) in the sub-endothelial space is a key process in the initiation of atherosclerotic lesion development. Functional changes induced by oxidized lipids in endothelial cells are early events in the pathogenesis of atherosclerosis. Oxidized-l-alpha-1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (ox-PAPC), a major component of minimally modified/oxidized-LDL (MM-LDL) mimics the biological activities assigned to MM-LDL both in vitro in a co-culture model as well as in vivo in mice. We hypothesized that ox-PAPC initiates gene expression changes in endothelial cells that result in enhanced endothelial/monocyte interactions. To analyze the gene expression changes that oxidized lipids induce in endothelial cells, we used a suppression subtractive hybridization procedure to compare mRNA from PAPC-treated human aortic endothelial cells (HAEC) with that of ox-PAPC-treated cells. We report here the identification of a gene, mitogen-activated protein kinase phosphatase 1 (MKP-1), that is rapidly and transiently induced in ox-PAPC-treated HAEC. Inhibition of MKP-1 using either the phosphatase inhibitor sodium orthovanadate or antisense oligonucleotides prevents the accumulation of monocyte chemotactic activity in ox-PAPC-treated HAEC supernatants. Furthermore, we show that decreased monocyte chemotactic activity in HAEC treated with sodium orthovanadate or MKP-1 antisense oligonucleotides is due to decreased MCP-1 protein. Our results implicate a direct role for MKP-1 in ox-PAPC-induced signaling pathways that result in the production of MCP-1 protein by ox-PAPC-treated HAEC.

Lie as narrative truth in abused adopted adolescents

Two case examples of abused adopted adolescents are discussed to highlight tension within the treatment relationship when the therapist is expected to accept without question a clearly unbelievable story. These examples illustrate how the lies of such youths can function as narrative truth. The unbelievable tales that emerge in the therapeutic work effectively alter the adolescents' perceptions about the perplexing loss of continuity, both internal and external, that occurred when they were removed from their homes. Characters in the stories represent fragmented self- and object-representations as victim, abuser, rescuer, and passive onlooker. Counterparts to the patient as victim, abuser, rescuer, and passive onlooker can be recognized in the therapist's subjective responses. If the therapist can use countertransference to inform an understanding of the treatment process, an appreciation emerges that the truth of the lie is in its impact. Decisions about how to intervene can then be crafted. The second separation-individuation intrinsic to adolescent development is understood to provide a ripe opportunity for this working-through process.

When confidentiality mandates a secret be kept: a case report

The success of group psychotherapy is impeded when group members maintain secrets and fail to self-disclose to other group members. However, revealing secrets sometimes conflicts with the legal and ethical constraints of confidentiality, thus placing a greater burden on the group. The case reported here illustrates how complex the dynamics of group therapy become when one group member maintains a secret. In this case, one member maintained a secret about another to preserve that individual's right to privacy and confidentiality. This case also details the group member's deliberations and confusion about the effect his secret had on the group's success, as well as the burden he experienced by choosing to preserve confidentiality at the expense of successful therapy for himself.

Clinical experiences with naltrexone in 370 detoxified addicts

Our studies have shown no evidence of toxicity and few side effects from naltrexone. It is a valuable adjunct in treating addicts who wish to be opiate free. Patients who drop out and return to treatment tend to remain longer with each successive readmission. Naltrexone has special potential for persons, such as an opiate-abusing physician for whom methadone maintenance is clearly inappropriate. A double-blind study has suggested that it may have value as a transitional treatment for detoxified methadone maintenance patients. Differences between naltrexone and cyclazocine suggest that a treatment combining these drugs should be explored.