Agnieszka Sagan

The aim of the study was to investigate the effect of cold atmospheric plasma (CAP) and sumac powder (Rhus coriaria L.) on the pH, total soluble solids, color, content of phytochemicals (carotenoids and polyphenols), and microbiological quality of freshly pressed carrot juice. Experiments were carried out with sumac powder concentrations of 0.5 and 3%, which were added before or after 20 min plasma treatment using a gliding arc reactor. The combination of CAP and 3% sumac powder resulted in very effective microbial reduction (to an undetectable level on each day of testing). These juices were characterized by an extended microbiological shelf life of up to 72 h. Additionally, the juice which was first enriched with 3% sumac and then treated with cold plasma, even on the last day of testing, contained 34.36 mg/100 mL of polyphenols and 3.49 mg/100 g more carotenoids than the control samples. The total effect of the application of these method is highly important for the improvement of the quality and safety of carrot juice.

Cereal bars are so-called convenience foods. Consumers value these products as a healthier alternative to traditional chocolate bars. Since these snacks usually contain added dried fruit, they have high potential for the utilisation of waste materials from the fruit industry. The study aimed to determine the effect of fortification of cereal bars with grape and apple pomace on their nutritional value, physical properties, and sensory quality. The control recipe was modified by replacing 10 or 20 g of sultanas with apple or grape pomace. The fortification with these food by-products resulted in a significant increase in the moisture content of the products, an increase in soluble fibre content, and a decrease in the level of antioxidant compounds. The strength of the cereal bars supplemented with grape and apple pomace increased. In addition, the panellists noticed a colour difference compared to the unmodified product (2 < ΔE < 5). A positive effect of the addition of the fruit pomace on the visual characteristics of the cereal bars was also observed. No changes were observed in the tastiness of the product. On the other hand, the aroma of the modified products and the texture of the bars containing the apple residue were less acceptable. In conclusion, cereal bars containing grape pomace and up to 10 g of apple pomace are characterised by high soluble dietary fibre content and desirable sensory and mechanical properties and are therefore recommended for industrial production.