Kinetics of transglutaminase-induced cross-linking of wheat proteins in dough

The effects of TGase in dough after 15, 30, 45, and 60 min of resting time after mixing were studied with a Kieffer test. The resistance to stretching of control dough did not change greatly during the 60 min time period after mixing. In dough, TGase decreased extensibility and increased resistance to stretching and this change was already observed after the first 15 min (first measurement). The higher the enzyme dosage was, the higher the magnitude of the rheological change was. All of the doughs that contained TGase 3.8 or 5.7 nkat/g flour had a higher resistance to stretching and lower extensibility than control dough 15 min after mixing. Resistance to stretching clearly increased at a dosage of 5.7 nkat/g flour during the 15-60 min period after mixing. Extensibility increased in the control dough and in the doughs with a low enzyme dosage almost at the same rate. The evolution of air bubbles during proofing was determined with bright field microscopy and image analysis. In the presence of 5.7 nkat/g TGase, the fermented dough contained more of the smallest and less large air bubbles in comparison to the control dough. The effect of TGase and water content on the specific volume of the conventional and organic wheat bread was studied. Water did not have a significant effect on the specific volume of bread. TGase increased the specific volume of breads baked from organic flour only, when additional water (+10% of farinogram absorption) and a small enzyme dosage were used. Microstructural characterization showed that bread baked without TGase from conventional flour had a stronger protein network than that baked from organic flour. TGase improved the formation of protein network in breads baked from either normal or organic flour but at higher dosage caused uneven distribution.     

Inorganic Pollution in PM10 Particles Collected Over Three French Sites Under Various Influences: Rural Conditions, Traffic and Industry

PM₁₀ particles were collected over three sites in France. The first one, Montagney was a rural site that was considered as a reference site. The second site Saclay, close to a highway, was used to study the influence of the traffic. The third site was Dunkerque, one of the most industrial areas in France for the production of steel, aluminium and petroleum refinement. More than 50 element concentrations were determined by instrumental neutron activation analysis and inductively coupled plasma–mass spectrometry. Comparisons between Saclay and Montagney shown that some elements, considered as crustal elements had similar concentration variations and weak (close to 1) enrichment factors. Elements with enrichment factors higher than 10 shown in Montagney correlated variations, with a Winter maximum, that should be due to Winter heating sources. Over Saclay, most of elements with high enrichment factors were attributed to the dense traffic of the highway. This is particularly true for Mn, Fe, Zn, Ba, Sb, Cu. Some additional elements correlated also, without a particular origin that can be ascertained. In Dunkerque, the most important industry is steel production. Correlation studies shown that Tl, Cs, Ba, Ag, Cu, Rb, Se, Mn, Pb concentration variations were closely associated to the Fe concentration variations. The second polluting industry is aluminium production. Correlation studies allowed to associate Ni, Y, Co, V, rare earth elements, Ti, Sr, Th, U, Ca, Sc, concentration variations to the aluminium concentration variations. A third important industry is petroleum refinement. The only element observed here and that is suspected to be emitted more specifically is La, used in cracking processes. An important enrichment of La with respect to Ce is observed. A strong decrease of the ratio Cl/Na was observed over the three sites, between the beginning of the experiment in Autumn 2005, and its end in Spring 2006. This was attributed to a release of gaseous HCl, produced by acidification of aerosols by other pollutants like NO _x and SO _x , that should have been oxidized to NO₂ and SO₃, then dissolved in the aerosols. The effects responsible for the loss of Cl, represents a large surface and long-term pollution event over the North of France. This work allowed a characterization of the heavy metal concentrations of the aerosol that will sustain results published in a companion paper, and that concerned the bio-accumulation of metals by Scleropodium purum, simultaneously exposed in the same sites.     

Sequence variation in the bolting time regulator BTC1 changes the life cycle regime in sugar beet

In beet production, flowering is an undesirable trait which drastically reduces yield. BOLTING TIME CONTROL 1 (BTC1) and BvBBX19 are major floral regulators in beet. Their proteins have been suggested to interact to jointly regulate their downstream targets BvFT1 and BvFT2. Annual and biennial BTC1 haplotypes differ by six non‐synonymous SNPs and a large insertion in the promoter of the biennial btc1 allele. We describe a new BTC1 allele which displays three nucleotide polymorphisms in the coding sequence and an 8‐bp insertion in the promoter region compared to the annual BTC1_d allele. The protein lacks a low‐complexity region, which likely alters its suggested ability to bind BvBBX19. Our findings demonstrate that little sequence variation in BTC1 is sufficient to turn an annual into a biennial genotype. Our results shed new light on the evolution of cultivated beets, and the identified btc1_l allele offers new possibilities to breed winter beets.