Unsaturated Solutions of Sodium Chloride as Reference Sources of Water Activity at Various Temperatures

In view of the uncertainty aboui the exact water activity.(a_w) of some solutions (saturated and unsaturated) used as references sources, the use of unsaturated NaCl solutions as isopiestic standards for calibration of hygrometers is proposed. It is shown that there is an excellent agreement on the exact value of NaCl solutions between various literature compilations and theoretical models. Further, it is also shown that in the important range (for food related applications) of 15–50°C the a_w of NaCl solutions is almost invariant.     

ANTENNAL AND BEHAVIORAL RESPONSES OF GRAPEVINE MOTH <Emphasis Type="Italic">Lobesia botrana</Emphasis> FEMALES TO VOLATILES FROM GRAPEVINE

Grapevine moth Lobesia botrana is the economically most important insect of grapevine Vitis vinifera in Europe. Flower buds, flowers, and green berries of Chardonnay grapevine are known to attract L. botrana for oviposition. The volatile compounds collected from these phenological stages were studied by gas chromatography—mass spectrometry, and the antennal response of L. botrana females to these headspace collections was recorded by gas chromatography—electroantennography. The compounds found in all phenological stages, which consistently elicited a strong antennal response, were pentadecane, nonanal, and -farnesene. In a wind tunnel, gravid L. botrana females flew upwind to green grapes, as well as to headspace collections from these berries released by a piezoelectric sprayer release device. However, no females landed at the source of headspace volatiles, possibly due to inappropriate concentrations or biased ratios of compounds in the headspace extracts.     

Incidence of autochthonous Argentinean mixed starter cultures in ripening of slurry cheese models

The effect of three mixed autochthonous starter cultures in ripening profiles of experimental semihard goat cheeses was evaluated under controlled microbiological conditions. Enterococcus faecium ETC3 and ETC6, Lactobacillus plantarum ETC17 and L. rhamnosus ETC14 were used. Combination of all strains showed the highest level of water soluble nitrogen fraction and total free amino acids (TFAA) at ripening day 1, the lowest level of phosphotungstic acid nitrogen soluble fraction and TFAA at ripening day 64 and the highest global impression. Principal component analyses were performed to establish amino acid profiles relations in the samples.     

Effect of Adjusting the Water Activity to 0.95 with Different Solutes on the Kinetics of Thiamin Loss in a Model System

The kinetics of thiamin degradation in a model system of pH 6.0 and water activity (a_w) 0.95 controlled with NaCl, KC1, glycerol or Na₂SO₄, was studied. The type of solute used to adjust a_w, had a dramatic influence on the rate of degradation of thiamin. The loss of vitamin increased in the following order: NaCl > KCl > glycerol > Na₂SO₄. Activation energies, however, were independent of the type of solute and ranged between24–28 kcallmole.     

Influence of the microenvironment on gene and protein expression of odontogenic-like and osteogenic-like cells

Progenitor cells play an important biological role in tooth and bone formation, and previous analyses during bone and dentine induction have indicated that they may be a good alternative for tissue engineering. Thus, to clarify the influence of the microenvironment on protein and gene expression, MDPC23 cells (mouse dental papilla cell line) and KUSA/A1 cells (bone marrow stromal cell line) were used, both in vitro cell culture and in intra-abdominal diffusion chambers implanted in 4-week-old male immunodefficient mice (SCID mice). Our results indicate that KUSA/A1 cells differentiated into osteoblast-like cells and induced bone tissue inside the chamber, whereas, MDPC-23 showed odontoblast-like characteristics but with a low ability to induce dentin formation. This study shows that MDPC-23 cells are especial cells, which possess morphological and functional characteristics of odontoblast-like cells expressing dentin sialophosphoprotein in vivo. In contrast, dentin sialophosphoprotein gene and protein expression was not detected in both cell lines in vitro. The intra-abdominal diffusion chamber appears as an interesting experimental model for studying phenotypic expression of dental pulp cells in vivo.     

Solute Effects at High Water Activity on Nonenzymatic Browning of Glucose-Lysine Solutions

The effect of different polyols (glycerol, propylene glycol, sorbitol, 1,3-butylene glycol, polyethylene glycol200, and polyethylene glycol 400) and various alkali metal chlorides (KCl, NaCl, LiCl, and CsCl) on the kinetics of nonenzymatic browning in glucose-lysine solutions, of high water activity (a_w) was studied. No particular inhibitory or promoting effect on browning of glucose-lysine solutions, when adjusting a, with the various polyols, was found. The alkali metal chlorides had a significant influence on the rate of browning and the relative effect of cations (Li > Na > K, Cs) paralleled the hydrated ionicradii in solutions.     

Effects of Lactobacillus rhamnosus GG addition in ice cream

A 2⁴ full factorial experimental design was applied to verify the effects of Lactobacillus rhamnosus GG (LGG) addition in retail-manufactured ice cream stored at two different freezing temperatures (−16°C and −28°C) and containing two different levels of sugar (15–22%) and fat (5–10%). In addition to microbial counts, the pH, acidity, viscosity of the mixes and functional properties of the ice creams were evaluated. Both fresh and frozen-thawed LGG cells underwent preliminary resistance tests to bile, antibiotics and acidity. The LGG strain proved to be highly resistant to most of the stress factors. When the micro-organism was added to ice cream mixes in a quantity of 10⁸ cfu/g, it did not change the overrun, firmness or melting behaviour of the finished product. Regardless of formulation, no count decay of LGG cells was observed in ice cream stored for up to 1 year.     

ANTIOXBDANT PROPERTIES OF OREGANO (ORIGANUM VULGARE) LEAF EXTRACTS

We tested the antioxidant properties of both aqueous and methanolic extracts of oregano (origanum vulgare) They proved to be effective in the inhibition of all phases of the peroxidative process: first neutralizing free radicals (superoxide anion, hydroxyl radical and 1,1‐diphenyl‐2‐picrylhydrazyl radical), then blocking peroxidation catalysis by iron (through iron‐chelating and iron‐oxidizing properties), and finally through interruption of lipid‐radical chain reactions (chain‐breaking activity). Their anti‐glycosylation activity was also effective. The glycosylation oflipoproteins is directly related to their peroxidation. The amount of extract used in our experiments was obtained from 0.1–1 mg of dried leaves, amounts far less than those normally used in the Mediterranean diet.