European Food Research and Technology最新文献

Sweet potato, Ipomoea batatas, is a widely cultivated vegetable and important food source. The leaves and stems of sweet potato contain polyphenolic natural products called caffeoylquinic acids (CQAs), which exhibit a variety of biological activities, including inhibition of amyloid peptide aggregation. Utilizing revised-phase HPLC, quantitative analysis of 3,4-, 3,5-, and 4,5-diCQA in sweet potato leaves and stems extracted under different solvent and temperature conditions. The total amount of polyphenols was also determined using the Folin-Ciocalteu method. The followings were found: (1) leaves and stems collected in spring contain more CQAs/polyphenols than leaves and stems collected in autumn; (2) roasting the leaves and stems does not affect the amounts of CQAs/polyphenols; (3) extraction in H₂O at 90 °C provides better yield of CQAs than extraction in H₂O at 5 °C. The results of the present study suggest that drinking hot H₂O extracts of sweet potato leaves and stems as a tea is a useful way to obtain CQAs/polyphenols as a healthy vegetable food material.

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The main objective of the present study was to evaluate terroir's role in white and red wine characteristics through human perceptions and electronic assessment. Douro wines, originating from the Douro Demarcated Region (DDR) in the North of Portugal, are renowned for their distinct terroir and historical significance. This study investigates twenty-one Douro wine samples (ten white, eleven red) from Baixo Corgo and Douro Superior through Fourier Transform Infrared (FTIR) spectroscopy, Electronic Nose (E-nose) analysis, and Quantitative Descriptive Analysis (QDA). The research has uncovered unique profiles for each sub-region, influenced by factors such as pH, alcohol content, and acidity. Through principal component analysis, the electronic nose analysis identifies separate clusters in red wines and highlights notable aromatic differences in white wines. The sensory analysis via quantitative descriptive analysis provides detailed wine profiles, emphasizing attributes such as persistence, sweetness, and acidity. Furthermore, emotional responses during wine tasting were assessed using FaceReader analysis, which revealed a range of emotions like happiness, sadness, surprise, fear, and disgust, with different intensities over time. These findings provide valuable insights for consumers, producers, and the enogastronomic industry.

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Hanseniaspora vineae is a non-Saccharomyces yeast used in winemaking to increase the complexity of wines. However, the fermentation rate in sequential inoculations may be challenging, particularly in industrial winemaking settings. This study aimed to assess how different co-inoculation protocols involving H. vineae and S. cerevisiae affect the fermenting performance and aroma of white and red wines. White and red wines were co-fermented with varying H. vineae-to-S. cerevisiae ratios (67%, 80%, 90%, 95%, and 98%). Results were compared to sequential and pure S. cerevisiae inoculation. Co-inoculation mitigated the inhibitory mechanisms associated with sequential inoculation, resulting in a reduction of 30 days and 6 days of fermentation for white and red wines, respectively. Moreover, the fermentation time in co-inoculation was similar to that of the controls, thereby avoiding the slowdowns typically observed in sequential inoculation. Five yeast-derived metabolic markers, two of which characterizing H. vineae metabolism, were studied to evaluate the processes. In white wines, β-phenylethyl acetate and benzyl alcohol were increased by H. vineae up to 64-fold and sevenfold, respectively, while ethyl hexanoate was fourfold higher in S. cerevisiae. In addition, 2-phenylethanol was up to twofold higher in S. cerevisiae. The results for isoamyl acetate varied depending on the co-inoculation ratio. At 67% and 80%, the H. vineae protocols showed the highest concentration, even exceeding that of S. cerevisiae pure inoculation. All compounds correlated linearly with the H. vineae-to-S. cerevisiae ratio at inoculum. The same trends were observed in red wines, but to a different extent.

Carrageenans are polysaccharides from red algae which are widely used as food additives and in other applications. Their structure is often described by different disaccharide repeating units, although it was already demonstrated that reality is more complex. In many studies, commercial carrageenans were used to establish structure function relationships, but a structural and compositional analysis was rarely conducted. Therefore, the aim of our study was to systematically and comprehensively characterize a broad collection of commercial carrageenans with different specifications from different manufacturers. For a more detailed characterization, an analytical approach based on partial enzymatic hydrolysis in combination with HPLC–MS and HPSEC-RI was developed and applied. Furthermore, rheology was used to gain detailed insights into the functionality of selected samples. Our results demonstrate that significant structural variation can be observed for commercial carrageenans. The samples contained different cations and the carrageenan type specified by the manufacturer did not always represent the structure of the corresponding polysaccharides. This was especially true for λ-carrageenans: Of the six commercial samples analyzed, none contained structural elements from the λ-type. Instead, the corresponding carrageenans contained κ-, ι- and ν-units. The application of the developed enzymatic-chromatographic approach showed that different hybrid carrageenans are present. In addition, the rheological analysis of the commercial carrageenan samples showed clear differences in the gelling properties upon calcium addition which could influence their behavior in different applications. Our results demonstrate that before an investigation of structure–function relationships, commercial carrageenan samples should be analyzed for their structure and composition. We also showed that the enzymatic-chromatographic approach described in this study is well suited for this purpose.

Cinnamomum verum (Cinnamomum zeylanicum or Ceylon cinnamon) is an aromatic medicinal plant, popularly used as a culinary spice and in various herbal commodities. The increasing demand and high economic value make C. verum a vulnerable target of substitution by its allied plant species. The present study is aimed at developing highly specific qualitative PCR and quantitative real-time PCR (qPCR) methods to authenticate and quantify C. verum in cinnamon-containing food products. The method targeted the ITS2-26S rRNA region of C. verum, demonstrating acceptable performance criteria and a sensitivity down to 1.24 ng. Moreover, the qPCR method was developed employing binary sample mixtures, spanning the linear dynamic range (100 to 1%, w/w) of C. verum in an adulterant species (C. cassia). The trueness (− 8.67 to − 20.69%) of the quantitative approach was effectively evaluated using blind sample mixtures. The developed method was applied to analyze 10 commercial cinnamon products, which reflected the practice of both complete and partial substitution of the higher-cost C. verum with its related, lower-cost plant species. In conclusion, the established method with specificity could not only detect but also quantify C. verum products, thus providing an accurate and powerful tool for the authentication of cinnamon-containing foods.

Bacillus cereus is a common contaminating bacteria and conditioned pathogens in food. Immunological methods or molecular biology assays that are currently available cannot distinguish between live and dead bacterial cells, which may overestimate the number of bacteria and lead to false-positive results. To solve this problem, we introduced propidium monoazide (PMA) and calcein in this study and established a real-time visual loop-mediated isothermal amplification (LAMP) detection method to detect viable B. cereus. In addition, the results can be detected visually with calcein dye or quantitatively by monitoring the amplification curve of the fluorescence signal. In this study, the results showed that the visual PMA-LAMP method had high specificity, strong anti-interference ability, a sensitivity of 1.16 × 10² CFU/mL, and that the whole reaction could be completed within 80 min. This method not only has high sensitivity, but also has a shorter reaction time and is faster. In the detection of artificially contaminated food samples, the lowest detection limit reached 6 CFU/mL after 3 or 4 h of enrichment. Therefore, the visual PMA-LAMP technology can provide an efficient and rapid method for the detection of live B. cereus bacteria.

The objective of the study was the development of nonconventional restructured freeze-dried multicomponent snacks obtained with the addition of chokeberry pomace powder (CP) supported by calcium ions (0, 0.01 and 0.05%). The study consisted of the evaluation of the impact of various quantities (1, 3 and 5%) of dried chokeberry pomace powder on selected physicochemical characteristics compared to snacks structured by pectin (0.5 and 1.5%). The results showed that the application of CP caused a significant reduction in the snacks’ water content and activity, which could contribute to enhanced stability. Hygroscopic properties and porosity also decreased with increasing quantity of CP, which was a consequence of structural changes in the material. The CP addition elevated the hardness of the snacks, however the effect was notably lower than after pectin incorporation. The use of the CP promoted the bioactive compound content and antioxidant activity of the freeze-dried snack. Total phenolic and anthocyanin contents elevated with the increasing quantity of CP, also followed by antioxidant activity improvement. The introduction of anthocyanins, which are red colorants, also caused notable changes in the color of the products. Overall, the application of chokeberry pomace resulted in obtaining an innovative snack option characterized by fortified bioactive compounds content and antioxidant activity. However, more research is needed to optimize also nutritional characteristics of the products.

Bacillus cereus is a spore-forming foodborne pathogen that causes emetic and diarrheal food poisoning. An emetic strain of B. cereus produces spores and an emetic toxin called cereulide, which exhibits high heat resistance. In this study, we investigated the effects of epigallocatechin gallate (EGCg), theaflavin-3’-gallate (TF2b), and theaflavin-3,3’-gallate (TF3), polyphenolic components of tea extracts, on the survivability, spores, and toxin of B. cereus. Among them, EGCg at 62.5 μg/mL and 250 μg/mL showed bacteriostatic and bactericidal effects on B. cereus by damaging the cellular membrane, causing leakage of cellular nucleic acid related substances, and thus inhibiting the growth of B. cereus. However, no significant effects were shown on spore germination by EGCg, TF2b, or TF3 at a concentration of 250 μg/mL in this investigation. Their inhibitory effects were primarily confined to the outgrowth of daughter cells after spore germination. Furthermore, quantitative polymerase chain reaction (qPCR) showed that they suppressed the activity of cesA, a gene associated with cereulide production. At concentrations of 125 µg/mL for TF2b and 62.5 µg/mL for TF3, a discernible attenuation of cytotoxic effects induced by cereulide on HEp-2 cells was evident.