Insight into the promoted recrystallization and water distribution of bread by removing starch granule - surface and - associated proteins during storage.

The influence of starch granule surface proteins (SGSPs) and starch granule-associated proteins (SGAPs) on bread retrogradation was investigated in a reconstituted dough system. The removal of both SGSPs and SGAPs resulted in poor bread qualities, decreasing specific volume and crumb porosity, leading to more baking loss and compact crumb structure. Particularly, removing SGSPs was effective in promoting the bread retrogradation. After 7 days of storage, the hardness of bread without SGSPs showed an increase of 353.34 g than the bread without SGAPs. Proton population and relaxation times exhibited that the absence of SGSPs significantly decreased the content of bound water from 11.51 % to 7.03 %, indicating lower water-holding capacity due to the loosen gelling structure. Compared to the control group, bread without SGSPs accelerated the starch recrystallinity by a reduction in soluble starch content, thereby increasing the retrogradation enthalpy and relative crystallinity through promoting the molecular reassociation in starch.

DNA-functionalized upconversion nanoparticles as biosensors for rapid, sensitive, and selective detection of Hg(2+) in complex matrices.

We have developed a facile one-step approach to make hydrophilic and DNA-functionalizable upconversion nanoparticles (UCNPs), which are used to act as a biosensor for determining Hg(2+) in complex matrices. The proposed approach is simple and exhibits low background interference, high sensitivity and rapid response.

Upconversion fluorescence resonance energy transfer biosensor for sensitive detection of human immunodeficiency virus antibodies in human serum.

A facile one-step approach was proposed to prepare hydrophilic and peptide-functionalized upconversion nanoparticles (UCNPs), which were used in the design of a biosensor for the sensitive and selective determination of human immunodeficiency virus antibodies in human serum based on FRET from the UCNPs to the graphene oxide.

A cytosine-rich DNA decorated gold nanoparticles surface enhanced Raman-scattering platform for sensitive and selective detection of silver ions.

In this work, we developed a label-free, homogeneous surface-enhanced Raman-scattering (SERS) platform for the rapid, simple and sensitive detection of Ag(+) by using the unmodified gold nanoparticles (AuNPs). It utilizes the different absorption properties of single-strand DNA (ssDNA) and double-strand DNA (dsDNA) on citrate-coated AuNPs and specific interactions between Ag(+) and cytosine-cytosine pairs. In the presence of Ag(+), the structure of ssDNA containing rich cytosine will form a duplex, resulting in the salt-induced aggregation of gold nanoparticles; the corresponding SERS signal transduction can be observed due to the plasmonic coupling of metallic nanoparticles. The assay possesses a superior signal-to-background ratio as high as ∼35.8 with a detection limit of 15 nM. This approach is not only rapid and convenient in operation, but also shows excellent selectivity, which makes it possible to detect Ag(+) in actual samples.