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[Display omitted] • A novel Colorimetric sensor array (CSA) for assessing oolong tea sensory quality. • Binding mechanism between pH indicators and metalloporphyrin was developed. • The effectiveness of CSA was assessed by comparing four classification models. • Oolong tea was successfully classified based on flavor intensity and grade level. Chinese oolong tea is famous for its rich and diverse aromas, which is an important indicator for sensor quality evaluation. To accurately and rapidly evaluate sensory quality, a novel colorimetric sensor array (CSA) was developed to detect volatile organic compounds (VOCs) in oolong tea. We further explored the binding mechanism between colorimetric dyes that trigger changes in charge transfer and visible color changes. Based on this, we modified and optimized the CSA to improve the sensitivity by 17.1–234.9% and the stability by 8.7–33.3%. The study also assessed the effectiveness of this method by comparing two linear and two non-linear classification models, with the support vector machine (SVM) model achieving the highest accuracy, identifying different flavor intensity and grades with rates of 100% and 95.83%, respectively. These findings sufficiently demonstrated that the novel CSA, integrated with the SVM model, has promising potential for predicting the sensory quality of oolong tea. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chlorine and QAC induced similar metabolic responses under planktonic state. • 60 °C heating induced amino acid anabolism for heat shock protein preparation. • Glu- and Arg-dependent acid resistance systems were initiated upon malic acid. • Distinctive resistance mechanisms were initiated under air-dried & washed state. Cronobacter sakazakii , an opportunistic bacterium, has raised a serious outbreak in powdered infant formula recent years. In this work, four sanitizing strategies used during infant formula processing, including chlorine, quaternary ammonium chloride (QAC), 60 °C heating, and malic acid (MA), were utilized against C. sakazakii among planktonic, air-dried (A), and air-dried & washed (AW) state, followed by an exploration of the metabolic responses induced by these treatments via a dual-platform metabolomics analysis with the ultra-high performance liquid chromatography-mass spectrometry and nuclear magnetic resonance. In the planktonic state, MA was the most effective in inhibiting bacterial growth, followed by chlorine, QAC, and 60 °C heating. Under A state, the efficacy of heating improved considerably, compared to that in the planktonic state, and remained unaltered under AW state. Chlorine and QAC were ineffective to control bacterial growth under A state, but their efficacy rose under AW state. Furthermore, the metabolomic analysis revealed chlorine induces amino acids catabolism, membrane lysis, and depression in carbohydrate and nucleotide metabolism in both planktonic and AW states, while the initiation of antioxidation mechanism was only found under AW state. Although the metabolic change caused by QAC in the planktonic state was similar to chlorine, the accumulation of osmoprotectant and membrane phospholipids within the AW cells reflected the effort to restore intracellular homeostasis upon QAC. Heating was characterized by considerable amino acid anabolism, along with mildly perturbed carbohydrate and nucleotide metabolism for heat shock protein preparation in both states. Lastly, MA promoted amino acid-dependent acid resistance under the planktonic state, and the regulation of antioxidation and osmoprotection under AW state. The metabolomics study elucidated the intracellular perturbation induced by common sanitizing, as well as the bacterial response, which provides insights for novel sanitization development. [ABSTRACT FROM AUTHOR]

[Display omitted] • S. Typhimurium showed strong desiccation resistance over 30 days. • Bacterial glycogen declined on D1 but increased back to a high level afterward. • Glycogen anabolism and catabolism were active throughout the desiccation process. • glgA and glgC insertion mutants displayed weaken desiccation resistance. • The role of glycogen in desiccation resistance varied over time. Salmonella enterica is known to survive in desiccate environments and is often associated with low-moisture foods (LMFs). In this work, S. Typhimurium ATCC 14028 was found to survive better by achieving the least reductions (3.17 ± 0.20 Log CFU reduction) compared to S. Tennessee ATCC 10722 (3.82 ± 0.13 Log CFU reduction) and S. Newport ATCC 6962 (6.03 ± 0.36 Log CFU reduction) after 30 days on surfaces with a relative humidity of 49% at ambient temperature. A metabolomic analysis revealed that S. Typhimurium was still active in energy metabolism after 24 h in the desiccate environment and glycogen, an energy reserve, was drastically reduced. We followed up on the glycogen levels over 30 days and found indeed a sharp decline on the first day. However, the glycogens detected on day 7 were significantly higher (P < 0.05) and thereafter remained stable above the original levels until day 30. The expression levels of both glycogen anabolism- and catabolism-related genes (csrA , glgA , glgC , glgX) were significantly up-regulated at all tested points (P < 0.05). The glgA and glgC insertion mutants displayed weaker survivability on both dry surfaces and in representative LMFs (flour and milk powder) compared to the wild-type strain. This work highlights the role of glycogen during different periods of desiccation, which may bring novel insight into mitigating Salmonella by disrupting glycogen metabolism. [ABSTRACT FROM AUTHOR]

[Display omitted] • KG and SA fat replacers dose-dependently reduced the gastric digestibility of protein in emulsion-type sausage. • XG show less influence on the digestibility of protein than KG and SA. • The reduced gastric digestibility was related to the enhanced viscosity of the digests. Hydrophilic polysaccharides have been widely applied as fat replacers in meat products, but their effects on the digestibility of meat proteins has seldom been studied. Replacement of backfat in emulsion-type sausage with konjac gum (KG), sodium alginate (SA) and xanthan gum (XG) were found to reduce the released amino group (–NH 2) during simulated gastric digestion and initial intestinal digestion. The suppressed gastric digestibility of protein was verified by the denser structures of protein gastric digests and reduced generation of peptides in gastric digestion when a polysaccharide was added. After the whole gastrointestinal digestion, high level of SA and XG resulted in larger digests and a more obvious SDS-PAGE band between 5 and 15 kDa, and KG and SA significantly reduced the total release of –NH 2. Additional of KG, SA and XG were found to the increase the viscosity of the gastric digests mixture, which could account for the reduced hydrolysis efficiency of pepsin during the gastric digestion, as evidenced in the pepsin activity study (decreased by 12.2–39.1%). This work highlights the influence of polysaccharide fat replacer on the digestibility of meat protein by changing the matrix characteristics. [ABSTRACT FROM AUTHOR]