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The Effect of the Cultivar and Process Parameters on Quality and Biologically Active Compounds Content in Impregnated Carrot Tissue
Vacuum impregnation (VI) allows soluble solids to be introduced into the porous matrix of a food material, modifying the composition of the tissue to facilitate further processing. The purpose of this research was to analyze the influence of pressure on the effectiveness of VI on a low porous material that is difficult to impregnate. Two cultivars of carrot (Baltimore F1 and Komarno) were subjected to VI at 5 and 30 kPa in a ternary solution of ascorbic acid (0.5%), citric acid (0.5%), and sucrose (8%) under isotonic conditions. The products were analyzed in terms of ascorbic acid content, degree of impregnation, and changes in structure, texture, color, antioxidant activity, phenolic content, carotenoids, and structure-forming compounds. Increases in vitamin C content (after VI) depended on the process conditions and ranged from 900% to 1300% in relation to the raw material. It was also observed that the extended impregnation time at a pressure of 5 kPa produced slices that were also impregnated in parenchyma area. The increased levels of polyphenolic compounds found in the saturated product may suggest that de novo synthesis under the influence of physiological stress had occurred.
The Effect of the Extraction Method on the Content of BioactiveCompounds and the Biological Activity of Nigella sativa Extracts
Ensuring food safety and consumer health are crucial elements of sustainable food safety management, requiring the use of substances that inhibit the growth of undesirable microorganisms at various stages of production. The negative impact of many of these on human health and the environment has led to increased interest in alternative solutions, such as plant extracts. The aim of this study was to determine the biological activity of extracts obtained from Nigella sativa seeds using various methods, including Soxhlet and ultrasound-assisted extraction (UAE) using hexane and methanol and supercritical CO2 extraction (SFE) assisted with methanol. The content of polyphenolic compounds, their composition, and biological activity depended on the extraction method and solvent type. All extracts exhibited antimicrobial activity against Gram-positive bacteria (Listeria monocytogenes, Priestia megaterium, and Staphylococcus aureus), Gram-negative bacteria (Salmonella Enteritidis, Pseudomonas aeruginosa, and Escherichia coli), yeasts (Candida albicans and Rhodotorula mucilaginosa), and filamentous fungi (Alternaria brassicicola, Pythium sp., Fusarium culmorum, and F. graminearum). The MIC values were in the range of <0.125 to 2 mg/mL for bacteria and 1 to 8 mg/mL for fungi, depending on the extract. Microscopic observations performed using optical and fluorescence microscopy showed changes in the viability and morphology of the fungal cells. TPC values ranged from 9.877 mg/g in hexane extract obtained by ultrasound-assisted extraction to 39.064 mg/g in extract obtained by Soxhlet method with methanol. No negative effects of the extracts on wheat seed germination were observed. Analysis of the composition of polyphenolic compounds revealed the presence of vanillic acid, hydroxybenzoic acid, syringic acid, protocatechuic acid, and p-coumaric, catechin, and epicatechin acids in all extracts. The extracts obtained with methanol, both by the Soxhlet method and by ultrasound-assisted extraction, also contained gallic acid, myricetin, luteolin, apigenin, and sinapic acid. In all extracts, thymoquinone ranged from 8.344 mg/g to 63.125 mg/g of extract, which was detected with the highest concentration in hexane extracts.