Biosynthesis of CMC-Guar gum-Ag0 nanocomposites for inactivation of food pathogenic microbes and its effect on the shelf life of strawberries.

A few fruits have short post-harvest life due to high metabolic activity, relatively high water content vulnerability towards microbes and loss of weight during their storage. Carboxymethyl cellulose (CMC)-Guar gum-silver nanocomposite films (CG-Ag0NC) are developed to address these issues. The silver nanoparticles were generated in the CMC-Guar gum matrix through a reduction by Mentha leaves extract. All the films were characterized by UV-vis spectroscopy, FT-IR, TGA, XRD, SEM, TEM, and zeta potential measurements. The antimicrobial activity of CG and CG-Ag0NC was measured by determining their zone inhibition values with ten food pathogenic microbes. The shelf life of CG-Ag0NC films was tested with the model fruit, strawberries, and compared with other packing films. The results are encouraging in terms of freshness, shelf-life and weight loss.

Pupillary threshold as an index of population vitamin A status among children in India.

Two hundred seven vitamin A-deficient southern Indian children aged 1-7 y (mean age: 56.9 mo) underwent testing of dark-adapted visual and pupillary thresholds in their village setting according to a previously reported protocol. One hundred thirty (62.8%) of the children also underwent serum retinol testing, and 178 (86.0%) participated in a randomized, placebo-controlled vitamin A dosing trial with pre- and postdose testing of dark-adaptation threshold. Most subjects (184 of 207, 88.9%) were able to complete pupillary testing, an objective sign requiring minimal cooperation, including a high proportion of the youngest children (72.2% of subjects aged 2 y). The proportion of children completing visual threshold testing, which requires greater understanding and cooperation, was significantly smaller than that able to complete pupillary testing (131 of 207, 63.3%; P < 0.0001, chi square). At baseline (predosing), the mean serum retinol concentration declined in linear fashion with a higher pupillary threshold (0.73 mumol/L with a score < or = 4; 0.47 mumol/L with a score > or = 8; P < 0.01). The mean pupillary threshold for these highly vitamin A-deficient Indian children (-0.622 log cd/m2) was significantly higher than that for 136 more moderately deficient Indonesian children (-0.985 log cd/m2; P < 0.001, two-sample t test) and 56 normal American children (-1.335 log cd/m2; P < 0.0001, two-sample t test). The improvement in pupillary dark-adaptation testing was not significant for children receiving vitamin A or placebo, though there was a nonsignificant trend toward greater improvement in children receiving vitamin A (P = 0.2, two-sample t test). Pupillary threshold testing represents a new, noninvasive, practical, and seemingly valid approach to assessing the vitamin A status of a moderately to severely deficient preschool population.