Protein-starch matrix plays a key role in enzymic digestion of high-amylose wheat noodle.

Wheat flour, consisting of a complex matrix of starch and protein, is used as a representative model of whole food here to investigate the binary interaction in relation to amylose level and hydrothermal treatment in noodles as a food exemplar. Noodle made of high-amylose wheat (HAW) flour showed an eight-fold higher resistant starch content, compared to the wild type. Protein removal under simulated intestinal digestion conditions resulted in higher starch digestion rate coefficients in raw and cooked flours. In cooked flours, the substrate becomes similarly accessible to digestive enzymes regardless of protein removal. The results indicate that the increased protein content in native HAW flour and thermal stability of starch in HAW noodles lead to higher food integrity and consequently enhance the resistance against α-amylase digestion. Overall, the study suggests that a diversity of starch-protein interactions in wheat-based food products underlies the nutritional value of natural whole foods.

Shedding PEG Palisade by Temporal Photostimulation and Intracellular Reducing Milieu for Facilitated Intracellular Trafficking and DNA Release.

The dilemma of poly(ethylene glycol) surface modification (PEGylation) inspired us to develop an intracellularly sheddable PEG palisade for synthetic delivery systems. Here, we attempted to conjugate PEG to polyethylenimine (PEI) through tandem linkages of disulfide-bridge susceptible to cytoplasmic reduction and an azobenzene/cyclodextrin inclusion complex responsive to external photoirradiation. The subsequent investigations revealed that facile PEG detachment could be achieved in endosomes upon photoirradiation, consequently engendering exposure of membrane-disruptive PEI for facilitated endosome escape. The liberated formulation in the cytosol was further subjected to complete PEG detachment relying on disulfide cleavage in the reductive cytosol, thus accelerating dissociation of electrostatically assembled PEI/DNA polyplex to release DNA by means of polyion exchange reaction with intracellularly charged species, ultimately contributing to efficient gene expression.