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The frequency and intensity of wildfires have been increasing over the last 50 years and negatively impacted the wine industry. Previous methods of smoke mitigation during grape processing have shown little impact in reducing smoke taint in wines. Therefore, a novel method of using edible spray coatings for vineyard application was developed to help prevent volatile smoke phenol uptake in wine grapes. Four cellulose nanofiber-based coating suspensions incorporated with chitosan and/or β-cyclodextrin were evaluated. Films derived from the coating suspensions were exposed to volatile phenols found in wildfire smoke (guaiacol, 4-methyl guaiacol, m-cresol, o-cresol, p-cresol, syringol, and 4-methyl syringol) and evaluated with ultraviolet-visible spectroscopy where the results indicated that the coatings could uptake smoke phenols in varying degrees. The coatings were also applied in a vineyard at three different application times during grape growth: pea-sized, pre-bunch closure, and both at pea-sized and pre-bunch closure. The results showed that the application time did not have a significant (p < 0.05) effect on berry size, weight, °Brix, pH, or titratable acidity. The type of coating, time of application and washing were found to impact the number of volatile phenols in the grapes after a smoke event. Results from this study indicated that edible coatings could help mitigate smoke uptake in wine grapes without sacrificing the growth and key composition parameters of wine grapes. PRACTICAL APPLICATION: This research provides a novel spray coating that can be applied to wine grapes in the vineyard to potentially mitigate volatile smoke compounds in wine grapes without impacting fruit growth and key compositional parameters of wine grapes, thus maintaining high quality of wines for consumers. Results from this study can also be potentially applied to other agricultural commodities to solve the issues caused by the wildfire smoke., (© 2022 Institute of Food Technologists.)

The discovery and application of new types of helical peptidic foldamers have been an attractive endeavor to enable the development of new materials, catalysts and biological molecules. To maximize their application potential through structure-based design, it is imperative to control their helical handedness based on their molecular scaffold. Herein we first demonstrate the generalizability of the solid-state right-handed helical propensity of the 4 13 -helix of L-α/L-sulfono-γ-AA peptides that as short as 11-mer, using the high-resolution X-ray single crystallography. The atomic level folding conformation of the foldamers was also elucidated by 2D NMR and circular dichroism under various conditions. Subsequently, we show that the helical handedness of this class of foldamer is controlled by the chirality of their chiral side chains, as demonstrated by the left-handed 4 13 -helix comprising 1:1 D-α/D-sulfono-γ-AA peptide. In addition, a heterochiral coiled-coil-like structure was also revealed for the first time, unambiguously supporting the impact of chirality on their helical handedness. Our findings enable the structure-based design of unique folding biopolymers and materials with the exclusive handedness or the racemic form of the foldamers in the future., (© 2021. The Author(s).)

New types of foldamer scaffolds are formidably challenging to design and synthesize, yet highly desirable as structural mimics of peptides/proteins with a wide repertoire of functions. In particular, the development of peptidomimetic helical foldamers holds promise for new biomaterials, catalysts, and drug molecules. Unnatural l-sulfono-γ-AApeptides were recently developed and shown to have potential applications in both biomedical and material sciences. However, d-sulfono-γ-AApeptides, the enantiomers of l-sulfono-γ-AApeptides, have never been studied due to the lack of high-resolution three-dimensional structures to guide structure-based design. Herein, we report the first synthesis and X-ray crystal structures of a series of 2:1 l-amino acid/d-sulfono-γ-AApeptide hybrid foldamers, and elucidate their folded conformation at the atomic level. Single-crystal X-ray crystallography indicates that this class of oligomers folds into well-defined right-handed helices with unique helical parameters. The helical structures were consistent with data obtained from solution 2D NMR, CD studies, and molecular dynamics simulations. Our findings are expected to inspire the structure-based design of this type of unique folding biopolymers for biomaterials and biomedical applications.