Helena Čížková

Benzoic acid (BA, E210) is a common food preservative and naturally occurring plant metabolite. It exists in plant tissues as free (f‐BA) and bound (b‐BA) forms. This makes accurate quantification challenging, as traditional extraction methods may underestimate total BA content. In this study, 26 berries and plum samples of 7 Vaccinium and Prunus taxa were analyzed by conventional shaking extraction (CSE, f‐BA) and ultrasound‐assisted extraction (UAE, total releasable f‐BA + b‐BA). Benzoic acid concentrations ranged from 4.1 to 581.8 mg/kg across taxa, with wild‐harvested V. macrocarpon reaching the highest levels and V. oxycoccos approximately 15‐fold lower. UAE increased measured BA over CSE in every sample (16%–41%), with a consistent gain of ∼20% in V. macrocarpon and Prunus spp. regardless of concentration, but a more variable and higher gain (up to 41%) in V. myrtillus , suggesting species‐dependent differences in BA binding within the cell wall. This shows the extraction method strongly affects measured BA content, relevant for EU food additive compliance. The results support UAE as a more reliable, though not absolute, estimate of total BA (t‐BA) in fruit products. These findings highlight the need for harmonized extraction protocols for compliance testing and further validation of UAE in other fruit and food matrices.

This study evaluated the impact of raw material thermal history (chilled vs. defrosted) and 12-month frozen storage (−18 °C) on the quality of mechanically separated common carp (Cyprinus carpio). Between months 6 and 12, a significant increase in volatile concentrations—primarily hexanal—and thiobarbituric acid reactive substances was observed, alongside a decrease in total volatile basic nitrogen. Microbiological quality remained stable throughout the period and none of the monitored pathogenic species (Escherichia coli, Clostridium perfringens, and Salmonella spp.) were detected. Histamine was the dominant biogenic amine, but its levels (7–34 mg/kg) were well below the safety limits. These results suggest that chilled and defrosted raw materials provide mechanically separated fish of similar quality, and the product is shelf-stable for at least six months.

The present study evaluates the impact of cavitation on the performance of the chemical refining of rapeseed oils and the enzymatic interesterification of fat blends using a powerful UP400S ultrasonicator (400 W, 20 kHz). Ultrasound-assisted alkali neutralization achieved efficiency comparable to that of the conventional 60 min process in only 7 min, with similar refining losses (5.04–6.80 wt.%), although slightly higher lipid peroxidation was observed. Performing the ultrasound cavitation under a protective nitrogen atmosphere minimized the formation of lipid peroxides and their breakdown products (i.e., hexanal, nonanal), partially protected tocopherols, and improved oxidative stability (IP at 120 °C = 3.9–4.4 h). Ultrasound-assisted enzymatic interesterification (EIE) of palm kernel fat and a palm stearin blend catalyzed by immobilized lipases (Lipozyme TL IM, Lipozyme RM IM, Novozyme 435) was carried out for the first time. Cavitation accelerated triacylglycerol rearrangement, reduced reaction time from 6 h (9.0·10⁻³ to 1.6·10⁻² min⁻¹) to only 1 h (5.5·10⁻² to 1.2·10⁻¹ min⁻¹), and significantly affected melting point stabilization and solid fat content profile. In summary, ultrasound cavitation substantially enhanced mass transfer and reaction kinetics, demonstrating strong potential for process intensification in the edible oil industry. Further optimization of reaction conditions is required before large-scale industrial implementation.

This study presents a comparative analysis of Vietnamese rubber ( Hevea brasiliensis ) and melaleuca ( Melaleuca cajuputi ) honeys, focusing on their pollen composition, physicochemical parameters, and volatile compound profiles. Melissopalynological analysis confirmed that both samples are monofloral, with dominant pollen types exceeding 45%. Rubber honey had a higher total pollen count and a more limited variety of pollen types, while melaleuca honey showed greater pollen diversity. Good manufacturing practice and quality indicators, such as moisture content, free acidity, and electrical conductivity (EC), were generally consistent across the samples. The moisture content averaged approximately 20.3%, marginally exceeding the Codex standard for honey. The free acidity levels adhered to established standards, with rubber honey measuring 24.5 ± 3.0 meq/kg and melaleuca honey at 22.5 ± 5.9 meq/kg. EC was comparable between the samples, recording values of 49.1 and 49.0 mS/m, respectively, both below the specified threshold for nectar honey. Freshness markers indicated low levels of hydroxymethylfurfural, with rubber honey at 8.6 ± 9.0 mg/kg and melaleuca honey at 9.7 ± 13.9 mg/kg. Diastase activity was higher in rubber honey (20.3 ± 3.9) compared to melaleuca honey (13.5 ± 2.5). The color appeared varied, with melaleuca measuring 52.0 ± 18.1 mm and rubber measuring 82.3 ± 15.1 mm (Pfund). Analysis of volatile compounds indicated that melaleuca honey possesses a more intricate chemical and aromatic profile, with methyl salicylate, terpinen‐4‐ol, and linalool oxides exerting significant influence on the classification of melaleuca samples. Conversely, isophorone and its derivatives appear to significantly impact rubber honey positioning. These results highlight the importance of volatile profiling for honey authentication and quality assurance.

Sulphite is?a?food additive used worldwide. Globally, for concentrations above 10 mg·kg–1, sulphite compounds must be?labelled as?sulphur dioxide (SO2) on?the packaging due to?their potential health risks. This study compares ...

The quality of black/red currant products, which are valuable components of a healthy diet, depends on many aspects, e.g., natural variability, climatic conditions, degree of ripeness, processing technology, and recipe. The aim of the study was to assess the effect of the harvest year (2020 and 2021) and different processes (with or without prepress enzymatic treatment) on the chemical composition of 38 laboratory-prepared black/red currant (BC/RC) juices and to compare them with 19 selected commercial products, using 20 compositional and quality markers. Significant differences (p < 0.01) were observed for BC in sucrose, Dp-3-glu, and Cy-3-glu content within the different processes, as well as fructose and ascorbic acid content within the harvest year (p < 0.05). The greatest differences between BC and RC juices were observed in ascorbic acid content (1567 mg/kg in BC and 261 mg/kg in RC), citric acid content (34.6 g/kg in BC and 23.2 g/kg in RC), and in the anthocyanin profile. The major anthocyanins of the currant products were identified as Dp-3-rut (39.1–50.4%), Cy-3-rut (30.1–39.1%), Cy-3-glu (3.6–18.2%), and Dp-3-glu (9.4–13.5%) in BC and Cy-3-glu (59.3–67.2%) and Cy-3-rut (14.2–19.8%) in RC. The chemical composition of commercial products was found to be highly variable and dependent on the recipe used.

Anthocyanins have received an?increased attention not only because of?its antioxidant activity; but because fortification of?food products by?minerals is?important due to?the lack of?some minerals in?population. The addition of?these minerals ...

Honey contains a wide range of inorganic substances. Their content can be influenced, i.e., by the type of soil on which the bee pasture is located. As part of this study, the mineral profile of 32 samples of honey from hobby beekeepers from the Czech Republic wasevaluated and then compared with soil types in the vicinity of the beehive location. Pearson’s correlation coefficient was used to express the relationship between mineral substances and soil type. There was a high correlation between antroposol and Zn (R = 0.98), Pb (R = 0.96), then between ranker and Mn (0.95), then regosol and Al (R = 0.97) (p < 0.05). A high negative correlation was found between regosol and Mg (R = −0.97), Cr (R = −0.98) and between redzinas and Al (R = −0.97) (p < 0.05). Both positive and negative high correlations were confirmed for phaeozem. The CART method subsequently proved that the characteristic elements for individual soil types are B, Ca, Mg, Ni, and Mn. The soil types of cambisol, fluvisol, gleysol, anthrosol, and kastanozem had the closest relationship with the elements mentioned, and it can therefore be assumed that their occurrence indicates the presence of these soil types within the range of beehive location.