QUENCHING MECHANISMS AND KINETICS OF CAROTENOIDS IN RIBOFLAVIN PHOTOSENSITIZED SINGLET OXYGEN OXIDATION OF VITAMIN D2

The oxidation of vitamin D₂ in a solution of 12% water, 88% acetone and 15 ppm ribqflavin under light or dark was studied by measuring the headspace oxygen. Ribofiavin accelerated the oxidation of vitamin D₂ by singlet oxygen under light, but did not affect vitamin D₂ oxidation under dark. Quenching mechanisms and kinetics within the range of 0–20 ppm β‐cawtene or fucoxanthin and with 0–80 ppm retinyl acetate or retinol on 15 ppm riboflavin photosensitized singlet oxygen oxidation of vitamin D₂ were also studied. The rate of singlet oxygen formation by 15 ppm riboflavin was 1.78 umole oxygen/mL headspace‐hour. The reaction rate constant of vitamin D₂ with singlet oxygen was 2.2 times 10⁷ M^?1A s^?1. The carotenoids minimized the oxidation of vitamin D₂ by quenching singlet oxygen. The total quenching rate constants of retinol, retinyl acetate, jucoxanthin and ft‐carotene were in the order of 1.22 times 10⁸, 5.98 times 10⁸, 1.78 times 10⁹ and 5.00 times 10⁹M^?1. s^?1 respectively, which suggests that as the number of double bonds of carotenoids increases, the quenching rate constant ofcarotenoid increases.     

LINKING MICROBIOLOGICAL CRITERIA FOR FOODS WITH QUANTITATIVE RISK ASSESSMENT

The current annual risk of acquiring a foodborne disease in the United States is estimated at 2.7 × 10^-2. The risk of associated death is estimated at 3.7 × 10^-5. These represent a health care burden >$3 billion. Using a risk assessment model one can identify levels of microbial contamination which may be unacceptable in foods and appropriate controls needed to reduce these levels. Salmonella bacteria continue to represent a large percentage of the identifiable infections. A model developed from human dose-response studies predicts the probability of infection for Salmonella at 7.5 × 10^-3 with exposure to a single CFU of the organism. Risks of severity (hospitalization), mortality, reactive arthritides, and mortality in the elderly are estimated at 3.1 × 10^-6, 7.5 × 10^-6, 1.7 × 10^-5, and 2.8 × 10^-4. Exposure to microbial contaminants needs to be evaluated on a single meal basis. For chicken, exposure may range from a single drum stick (38g) to a half broiler (176g) but averages around 80g. For beef between 51 and 85g may be consumed during a single meal. Therefore, methods for monitoring must be able to detect at least 1 CFU/80g. Risks for some pathogenic E. coli are estimated at 1,000 to 10,000 less than Salmonella. Therefore, use of coliforms as indicators needs to be assessed and related to occurrence and survival and regrowth potential of the enteric bacteria of greater public health concern. Because, 20% of the U.S. population may be considered to be in a special population category and at an increased risk of severe outcomes, no more than 20% failure of a standard should be acceptable .     

Riboflavin Photosensitized Singlet Oxygen Oxidation of Vitamin D

Samples containing various levels of vitamin D and riboflavin, with and without ascorbic acid or a-tocopherol were prepared in a model system. Samples were stored in the light or in the dark at 45®C for up to 8 h. Headspace oxygen was determined by gas chromatography with thermal conductivity detection. Oxidation of vitamin D was not observed in samples without riboflavin stored in the light nor in samples with riboflavin stored in the dark. Vitamin D with riboflavin was oxidized under light. α-Tocopherol quenched singlet oxygen at a rate of 2.52 × 10⁸ M^-1 sec^-1, whereas ascorbic acid quenched singlet oxygen at a rate of 2.23 × 10⁷ M^-1 sec^-1.     

EFFECT OF NURTURANCE ON WIVES' APPRAISALS OF THEIR MARITAL SATISFACTION AND THE DEGREE OF THEIR HUSBANDS' APHASIA.

IT WAS HYPOTHESIZED THAT: (1) THERE IS A RELATIONSHIP BETWEEN WIVES' DEGREE OF NURTURANCE (NEED TO GIVE AFFECTION AND CARE) AND THEIR PERCEPTION OF THE SEVERITY OF THEIR HUSBANDS' SPEECH DISABILITIES, (2) THERE WOULD BE A POSITIVE RELATIONSHIP BETWEEN WIVES' NURTURANT NEEDS AND THEIR REPORTS OF MARITAL SATISFACTION, AND (3) WIVES WHO WERE HIGH IN NURTURANCE WOULD REPORT FULFILLING AFFECTIONAL ROLES AND WOULD REPORT SHARING ACTIVITIES WITH THEIR HUSBANDS MORE OFTEN THAN LOW-NURTURANT WIVES. SPEECH RATINGS WERE MADE ON THE FUNCTIONAL COMMUNICATION PROFILE. MARITAL SATISFACTION WAS MEASURED BY A MARITAL ROLES AND ATTITUDES QUESTIONNAIRE, A NEED-SATISFACTION QUESTIONNAIRE, AND A MARITAL HAPPINESS SCALE. THE MAJOR HYPOTHESES WERE CONFIRMED WITH EXCEPTION OF THE FULFILLMENT OF AFFECTIONAL ROLES. HERE NO SIGNIFICANT DIFFERENCES WERE FOUND BETWEEN HIGH-NURTURANT AND LOW-NURTURANT GROUPS. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intensity - Concentration Relationships for Sugar and Salt Solutions

SUMMARY– Intensity of sweetness or saltiness was examined as a function of concentration and logarithm of concentration in solutions of sugar and salt in water and orange or tomato juice. Solutions were Judged in linear or logarithmic concentration increments. No clear-cut evidence was found to show that the logarithmic function described the relationship better than the linear function. In the Juice experiments, the failure to demonstrate a logarithmic function apparently resulted from the panel's insufficient discriminating power relative to deviations from regression arising from fitting a linear function to logarithmic data. In the water experiments, where such discriminating power was present, some evidence that the judging was on a linear continuum was found.