## 2 Materials and the Experimental Design  
### Study Material  
The research material was raw red annual peppers (_Capsicum annuum_ L.) of the _Roberta_ variety and the culinary products obtained from them. The fruiting bodies of red peppers (Subcarpathian Voivodeship, Poland) were intended for the study. The fruiting bodies intended for the study were fresh, with the shape and uniform colour characteristic of the cultivar, with a size in the 200-300 g range. Approximately 20 kg of peppers was used for the study. After pre-sorting (e.g., eliminating fruiting bodies that were too small or too large and not correctly coloured; the maturity was assessed visually), the peppers were divided into three equal parts for the three packaging methods. Each packaging method included four treatment options: no heat treatment (control) and three sous vide heat treatment options. Immediately after purchase, the fresh vegetables were pre-treated, which included the removal of the seed nests, washing in running cold water and drying, and slicing into oblong rectangular pieces of 20 \(\pm\) 4 g (dry weight range); their length and width may have varied but was approximately 2.5 cm \(\times\) 4 cm. The heat treatment of the peppers was carried out under vacuum conditions for all the packaging methods (ATM, VAC, and MAP). The VAC products were cooled after heat treatment and destined for storage. The ATM and MAP products were repackaged under aseptic conditions into a suitable gaseous atmosphere after processing and cooling (ATM and MAP). The packaging material for packaging under an unchanged gas atmosphere was string pouches made of 100 \(\upmu\)m thick polyethene (PE) transparent film (Inter Arma, Rudawa, Poland). A 70 \(\upmu\)m thick, 100 \(\times\) 150 mm double-layer polyamide/polyethylene (PA/PE) (Inter Arma, Rudawa, Poland) transparent film was used for the vacuum packaging of culinary products. An RM Gastro VBN-18 SB (RM Gastro, Prague, Czech Republic) packaging machine was used for the VAC packaging of culinary products. The following parameters were used during packaging: vacuum generation time 5 s, vacuum 0.9 MPa, and sealing time 13 s. The VAC packaging conditions were experimentally determined using an optimum pressure and sealing time that did not damage the culinary productsduring the packaging process. For the modified gas atmosphere packaging of culinary products, a two-layer polyamide/polyethene (PA/PE) film with a thickness of 70 \(\upmu\)m and dimensions of 100 mm \(\times\) 150 mm was used. An RM Gastro VBN-18 SB (RM Gastro, Prague, Czech Republic) packaging machine was used for the MAP packaging of culinary products. BIOGON C30 food gas (Linde, Dublin, Ireland) had a composition of 30% CO\({}_{2}\) and 70% N\({}_{2}\). The following parameters were used during packaging: pressure build-up 1 MPa, gas injection 10 s, and sealing time 10 s. The MAP packing conditions were experimentally determined so that the gas filled the pack's volume. Sous vide hydrothermal treatment was carried out using a water circulator (CASO 2000, Arnsberg, Germany). Three variants of hydrothermal treatment of peppers were used for each packaging method: 30 min at 60 \({}^{\circ}\)C packed in an unaltered gas atmosphere (30 min/60 \({}^{\circ}\)C ATM), vacuum packed (30 min/60 \({}^{\circ}\)C VAC), and packed in a modified gas atmosphere (30 min/60 \({}^{\circ}\)C MAP); 15 min at 70 \({}^{\circ}\)C in an unchanged gas atmosphere (15 min/70 \({}^{\circ}\)C ATM), vacuum packed (15 min/70 \({}^{\circ}\)C VAC), and packaged in a modified gas atmosphere (15 min/70 \({}^{\circ}\)C MAP); and 8 min at 80 \({}^{\circ}\)C in an unchanged gas atmosphere (8 min/80 \({}^{\circ}\)C ATM), vacuum packed (8 min/80 \({}^{\circ}\)C VAC), and packaged in a modified gas atmosphere (8 min/80 \({}^{\circ}\)C MAP). The aforementioned hydrothermal treatments and packaging methods, together with the raw peppers' packaging, resulted in 12 test samples. Each test sample was prepared in 54 replicates (9 test dates were planned, each with n = 6).