Ufe 500 oven

The gelatin film forming solution was prepared by dissolving 5 wt.% of bovine gelatin powder (Sigma-Aldrich, Taufkirchen, Germany) in distilled water at 60 °C for 30 min. Then, 60-µm thick films were obtained by casting the gelatin film forming solution over a covered Mylar® (DuPont Teijin Films^TM, Cotern, Luxembourg) mold. The evaporation of water was carried out at 22 ± 2 °C and at 50 ± 10% relative humidity. Dehydrothermal (DHT) crosslinking [16 (link)] of the gelatin films was achieved by drying the films at 100 °C for 1 h, then heating them to 150 °C for 8 h in a Memmert UFE500 oven (Memmert GmbH, Schwabach, Germany). This DHT treatment time was chosen as the compromise between the fabrication convenience and the achieved performance properties of the films (see Appendix A). The treatment formed crosslinks through a condensation reaction between the carboxyl and amino groups in the gelatin. The samples were stored for 1–2 days at room temperature in a vacuum desiccator before being cut into 20 cm long strips using an infrared laser machine (Laser solution LS100, Gravotech Marking, La Chapelle Saint-Luc, France) and making the capsules.

T-550 commercial all-purpose wheat flour (Tena-Žito Ltd., Đakovo, Croatia) was used to produce the cream crackers. The tomato pomace (TP) was produced from ripe tomatoes grown in 2019 in the Razgrad region, Bulgaria. After removing the pulp, TP was dried for 48 h at 45 °C in a UFE 500 oven (Memmert GmbH, Schwabach, Germany), then ground (powder size < 0.5 mm) with an IKA MF10 grinder (IKA^®-Werke GmbH & Co. KG, Staufen, Germany) and stored at −18 °C. The margarine (Zvijezda Ltd., Zagreb, Croatia), with a total fat content of 70%, contained vegetable fats (palm oil), water, vegetable oils (sunflower, rapeseed), iodised salt 0.4%, emulsifier (E 471), preservative (E 200), acidity regulator (citric acid), flavouring, and colouring (β-carotene). The other ingredients were bought from local stores in Osijek, Croatia.