Glycerol

Folin–Ciocalteu’s reagent, acetic acid, gallic acid, 2,2-diphenyl-1 picrylhydrazyl (DPPH), methanol (HPLC grade), ethanol, water (HPLC grade), acetonitrile (HPLC grade), sodium carbonate, sodium acetate and maltose (>97.0%) were purchased from Sigma Aldrich Chemical Co. (St. Louis, MO, USA). Phenolic standards: hydroxytyrosol, caffeic acid, vanillin, luteolin and rutin were supplied from Sigma-Aldrich (St. Louis, MO, USA) and oleuropein was purchased from Extrasynthese (Genay, France). Choline chloride (>98.0%) and lactic acid (>98.0%) were obtained from Acros Organics (Geel, Belgium), citric acid (>98.0%) was purchased from Univar (LaiwuTaihe Biochemistry Co. Ltd., Laiwu, China) and glycerol (>99.0%) was purchased from Lach-Ner (Neratovice, Czech Republic).

Chitosan—low molecular weight, phosphate-buffered saline tablets, select yeast extract, tryptone, agar, Tween 80, and l-histidine dihydrochloride were purchased from Sigma-Aldrich; acetic acid, sodium chloride p.a., and n-hexane 99% p.a. from Penta Chemicals; sodium tripolyphosphate (TPP) from Acros Organics; ethanol 99.8% for UV/VIS spectroscopy, and glycerol anhydrous g. r. from Lach-Ner; curcumin 99.9% from Chromadex; Brain–Heart-Infusion broth (BHI, Hirn-Herz-Glucose-Bouillon für die Mikrobiologie) from Carl Roth; sunflower lecithin from Fichema s.r.o. Materials for finger replica preparation—FIMO^® soft oven-bake modelling clay and liquid silicon paste with a hardener were purchased from Staedtler.
Antimicrobial foam soap was purchased from Tork. Chlorhexidine digluconate (CHG) 25% w/w aqueous solution was provided by Zentiva, k.s. Two commercially available sanitisers used as a positive control for bacterial testing were purchased in a local store, i.e., ethanol-based gel (72% w/w) from Sanytol and 2% CHG alcoholic solution (IPA 70% v/v) from B. Braun Medical AG.

The probiotic culture of Bifidobacterium animalis subsp. lactis BB-12 was obtained from Chr. Hansen (Hoersholm, Denmark). Sodium alginate, calcium chloride, xanthan gum, κ-carrageenan, pectin, inulin, glucose, and Tween 80 were provided by Sigma-Aldrich Chemie GmbH (Taufkirchen, Germany); glycerol was purchased from Lach-Ner (Brno, Czech Republic); and nanocrystalline cellulose (CNC) from CelluForce (Montreal, Canada). Olive pomace oil was kindly provided by MINERVA S.A. (Athens, Greece) and sweet whey with the following specifications: humidity 1%, fat content 1%, protein content 10.2%, lactose (hydrated) 75%, ash content 7.3%, was kindly provided by ION S.A. (Piraeus, Greece). Whole-fat milk was obtained from the local market. The materials for the microbiological analyses, such as MRS agar, Ringer’s solution, citric acid, and disodium phosphate, were acquired from Merck (Taufkirchen, Germany), whereas l-cysteine-HCl, neomycine sulfate, nalidixic acid, lithium chloride, and paromomycine sulfate by Thermo Fischer Scientific (MA, USA). Pepsin, pancreatin, and bile extract were obtained from Acros Organics (New Jersey, USA).