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[Display omitted] Distinguishing substituted aromatic isomers is a challenging task because of the great similarity of their physicochemical properties. Considering xylene isomers have drastically different geometrical shapes, we predict this would show great impact on the self-assembling behavior of various xylene isomer@cyclodextrin inclusion complex. Through host–guest crystalline self-assembly, among three isomers, only ortho -xylene is capable to form hydrogels with α-cyclodextrin. ROESY NMR, molecular simulations and circular dichroism spectra suggest that the ortho selectivity comes from the difference in the conformation of host–guest building block. The larger volume, and steric hinderance of the ortho isomer make it most possibly decrease their tendency to adopt more mobile orientations in cyclodextrin-based complex as meta and para isomers do, resulting in gel formation. Herein, we report a novel, facile and environmentally-friendly protocol on the recognition of ortho benzene isomers using α-cyclodextrin through host–guest crystalline self-assembly. Visual recognition of ortho -xylene is achieved through amplifying the structural difference of xylene isomers at molecular scale into macroscopic scale. We believe this work unveils subtle rules to control macroscopic assemblies at the molecular level and highlights the potential of using macrocyclic compounds to improve the quality and reduce the energy bill for separation in petrochemical industry. [ABSTRACT FROM AUTHOR]

The bioactive peptides derived from sweet apricot kernel residue after oil extraction exhibit different bioactivities, but their structure-activity relationships have not yet been established. In this research, the antioxidant activities (hydroxyl, superoxide anion, DPPH radical scavenging capacity and iron-binding ability) of sweet apricot kernel protein hydrolysates (SAKPHs) obtained by different enzymes at the temperature range (37–70 °C) were evaluated. The amino acid sequences of the hydrolysates by different enzymes were identified by LC-ESI-MS/MS. The results showed that five novel antioxidant peptides with Lysine at the C-terminal end were found in the Neutrase' SAKPHs. Two peptides with Serine-terminal end in the Alcalase' SAKPHs and with N-terminal end in the Papain' SAKPHs were obtained respectively. Three atypical peptides were detected in the Flavourzyme' SAKPHs. The SAKPHs by the Alcalase (SAKPHs-A) at 50 °C had highest degree of hydrolysis and a relatively smaller molecular weight distribution compared with the other three proteases, and presented the higher antioxidant activity. The N-terminal peptide SHNLPILR containing a side chain combination of aspartic acid and histidine contributes to the stronger antioxidant activities of SAKPHs-A. This research supplies a guideline for functional peptides released from dietary proteins by the utilization of specific enzymes in the food industry. • The peptide of Lys-terminal end easily reacts with DPPH radicals. • The peptide of Ser and N-terminal end exerted higher antioxidant activities. • Twelve novel antioxidant peptides were identified in sweet apricot kernel protein. • Relationship of enzymes-dependent structure and antioxidant activity was revealed. [ABSTRACT FROM AUTHOR]