We have developed a new healthy snack based on celery root enriched with vegetable juices. Vacuum impregnation was used the task of which was to introduce additional valuable substances, improving properties. Thus, prepared material was dried by various methods (sublimation, vacuum, convection) using optimal conditions for the process. In the tested sample, 41 bioactive compounds and 73 volatile compounds were identified. Vacuum impregnation of celery root in the juices of onion, kale and celery stalks significantly affected the profile of bioactive compounds, Volatile Organic Compounds (VOCs), total phenolic content, antioxidant properties, drying process kinetics and physical properties of the dried products. The highest nutrient values were recorded in celery samples after impregnation with kale and onion juice. Due to its good functional and nutritional properties, the material such as celery obtained as a result vacuum impregnation process can be envisioned as the future in creating novel functional foods.

The aim of this study was to determine the effects that the type of impregnating solution and drying method (freeze drying (FD) and vacuum drying (VD) at 45 °C and convective drying (CD) at 50, 60, and 70 °C) had on the physicochemical and quality properties of courgettes. Courgette slices were vacuum-impregnated (6 kPa) in freshly squeezed onion, kale, and onion and kale (50:50) juices with 3% NaCl solution (N). The application of vacuum impregnation (VI) with impregnating solutions from freshly squeezed onions and kale had a beneficial effect on the bioactive values of courgette. The highest contents of quercetin (41.84 μg/g d.m.) and carotenoids (276.04 μg/g d.m.) were found in courgette impregnated with onion juice after freeze drying. The highest values of lutein and zeaxanthin (216.42 μg/g d.m.) were recorded for courgette impregnated with kale juice and convective dried. By analysing the kinetics of convective drying, the best matching of the logistic model was found. Increasing the drying process temperature from 50 to 70 °C reduced the drying time from 15% to 36%, depending on the type of impregnating solution used. Water activity < 0.6 was recorded for courgette dried by freezing, vacuum, and convection at 60 and 70 °C. Conclusions: The vacuum impregnation process and the impregnation solutions from freshly squeezed vegetables can be used to develop new snacks with high levels of bioactive compounds. The FD method is the most appropriate considering both the bioactive compounds content and the obtained colour and water activity.

A comparative study was conducted on the effect of vacuum impregnation and drying methods on the production of dried sweet potatoes with high bioactivity. The present study determined the quality and physicochemical properties of dried sweet potato depending on the used impregnating solutions. Sweet potatoes were pretreated in freshly squeezed onion (O) and kale (K) juice, onion and kale (OK) mixture (1:1), and sodium chloride solution. Vacuum impregnation (VI) was carried out under reduced pressure (6 kPa) for 2 min, after which the impregnating solution was dispensed and maintained under vacuum for 4 min. Sweet potato slices were dried using vacuum drying (VD) and freeze drying (FD) methods. Higher content of polyphenols, carotenoids, and chlorophyll, as well as increased antioxidant capacity and higher VOC profile, were recorded for the dried products obtained using the sublimation method. The use of vacuum impregnation reduced the hardness of the products and other textural characteristics, such as cohesiveness, springiness, and gumminess. Furthermore, we found that vacuum impregnation pretreatment was a beneficial method for improving the characteristics of dried vegetables. The highest content of phenolics, carotenoids, and chlorophylls in dried sweet potatoes were recorded when samples were impregnated with onion and kale juice. For the fresh sweet potato, the highest contribution in VOC composition had phenylacetaldehyde (44.90%), (E)-2-octen-1-al (9.43%), and benzaldehyde (8.18%), respectively. The interesting content of VOC profile compounds in dried sweet potatoes was recorded when samples were impregnated with kale juice.

The paper presents the results of a study on the water absorption capacity and solubility of biodegradable starch foams produced with single-screw extruder TS-45 with L/D=12. Two different moulding dies were used: one with a circular hole with the diameter of 3 mm and one with a ring hole with...

The drying process is used in the food industry to extend the shelf life of fruits and vegetables without the use of preservatives. As quality, visual, and aroma characteristics are important determinants of consumer interest, they play a key role in the development of new foods. In the present study, vacuum impregnation (VI) was used prior to vacuum drying (VD) and freeze drying (FD) of courgette and broccoli. Organic beet juice was used to produce the novel snacks. The study showed that the use of vacuum impregnation significantly affected the VOCs profile (volatile organic compounds profile), in which the following compounds were found: viz: 2-(E)-hexen-1-ol, 2-(Z)-hexen-1-ol and aceto-phenone. VI caused a decrease in volumetric gel index (VGI), drying shrinkage (S), water activity (AW), decreased color saturation (∆C), and increased dry matter content (DM). All these properties testify to the positive effect of the pretreatment used. The drying methods used had a significant effect on the properties of the dried vegetables. The dries obtained by the FD method showed higher density and water activity, as well as better preserved color (lower ∆E) and higher VOCs, so it is considered that freeze drying is a suitable method for obtaining novel courgette and broccoli snacks.

More and more people begin to pay attention to how foodstuffs are produced. Due to the changing lifestyle, consumers seek products that do not require long preparation. The extrusion-cooking process responds to this type of applications with an easy management of processing promising product stability and quality. Extrusion-cooking involves the extruding of granular material under high pressure and high temperature. Such a method of treatment of raw materials makes extrudates produced from natural ingredients, i.e. corn or rice, suitable for direct consumption and guarantees their prolonged shelf-life. In our study, mixtures for instant grits were prepared from corn with a rice additive of 25% and 50%. Extrudates were prepared using a single-screw extruder TS-45 (L/D=12:1). The range of the temperatures of the extrusion process was 125/130/135 °C. The process was carried out with the variable screw rotation speed of 80, 100 and 120 rpm. This paper presents the results of process efficiency and energy consumption during the extrusion-cooking of instant corn-rice grits. Based on a bidirectional analysis of variance, the process efficiency, regression equation and correlation coefficients were determined for evaluating the impact of the processing conditions on selected properties.