. (a) The impact of silk fibroin coating was investigated on freshly picked strawberries. (i) Silk fibroin was extracted from Bombyx Mori cocoon fibers by dissolution in 9.3 M LiBr solution and (ii) dialysis in deionized water. The concentration of the protein in water was then adjusted to 1 wt%. (iii) Coating of strawberries was then achieved by dip coating process in silk fibroin suspension (1wt%). The dip coating process was repeated up to 4 times. iv) Beta-sheet content in silk fibroin edible coatings was modulated using water annealing post-processing. The longer the exposure to water vapour (up to 12 hours), the higher the beta-sheet content of the protein, as reported in Table 1. v) Silk fibroin-coated strawberries were then left at room conditions (T = 22 °C, RH = 38%) to investigate the impact of the coating on the quality of the fruit. Crystal violet dye was used to stain the silk fibroin coating. (b) Representative images of stained strawberries i) freshly picked, ii) coated silk fibroin edible coating (4 dip coating processes, 23% betasheet, i.e. no water annealing applied), iii) coated with silk fibroin (4 dip coating processes), 58% beta-sheet, i.e. exposed to water annealing post-processing. The crystal violet dye is barely visible on the surface of the coated strawberries (black dots) due to the few-micron thickness of the coating. (c) Stereoscopic images of the surface and of the cross-section (insets) of crystal violet-stained fresh strawberries (i) as picked, (ii) coated with silk fibroin with 23% beta-sheet content and (iii) coated with silk fibroin (4 dip coating processes) with 58% beta-sheet content. Scale bars: 2 mm.