Effect of hydrolyzed soybean on the volatile flavors and microbial community in the traditional brewing process of chi-flavor Baijiu.

Addition of soybean in raw materials could improve the flavor of chi-flavor Baijiu (CFB) in production. For investigating the mechanism of flavor improvement during fermentation, the changes of volatile flavors and their relationship with microbial community were analyzed. The results showed that the average contents of lactic and acetic acid in EG (added with hydrolyzed soybean) samples were higher those of CK (without hydrolyzed soybean) samples. The contents of main volatile esters, including ethyl acetate, ethyl palmitate, and ethyl benzoate, in EG samples were higher than those in CK samples at the end of fermentation. The content of alcohols in EG sample was 140.55 mg/L, higher than that in CK sample at the end of fermentation. Especially, the average content of characteristic flavor ß-phenylethanol in EG samples increased 17.6% in comparison with that in CK samples during fermentation. Lactobacillus and Pediococcus were the dominant bacterial genera, whereas Saccharomyces, Mortierella, and Trichosporon were dominant fungal genera in both CK and EG samples. Lactobacillus and Weissella confusa showed strong positive correlation with ß-phenylethanol, ethyl acetate, and ethyl benzoate. This study provides an in-depth analysis of the effects of hydrolyzed soybeans on the volatile flavor compounds and microbial communities of CFB and theoretical guidance for improving the quality of CFB.

"Two-in-One" PtPdCu Trimetallic Multifunctional Nanoparticles-Mediated Dual-Signal-Integrated Aptasensor for Ultradetection of Enrofloxacin.

Balancing the accuracy and simplicity of aptasensors is a challenge in their construction. This study addresses this issue by leveraging the remarkable loading capacity and peroxidase-like catalytic activity of PtPdCu trimetallic nanoparticles, which reduces the reliance on precious metals. A dual-signal readout aptasensor for enrofloxacin (ENR) detection is designed, incorporating DNA dynamic network cascade reactions to further amplify the output signal. Exploiting the strong loading capacity of PtPdCu nanoparticles, they are self-assembled with thionine (Thi) to form a signal label capable of generating signals in two independent modes. The label exhibits excellent enzyme-like catalytic activity and enhances electron transfer capabilities. Differential pulse voltammetry (DPV) and square-wave voltammetry (SWV) are employed to independently read signals from the oxidation-reduction reaction of Thi and the catalytic oxidation of hydroquinone (HQ) to benzoquinone (BQ) by H2O2. The introduced DNA dynamic network cascade reaction modularizes sample processing and electrode surface signal generation, avoiding electrode contamination and efficiently increasing the output of the catalyzed hairpin assembly (CHA) cycle. Under optimized conditions, the developed aptasensor demonstrates detection limits of 0.112 (DPV mode) and 0.0203 pg/mL (SWV mode). Additionally, the sensor successfully detected enrofloxacin in real samples, expanding avenues for designing dual-mode signal amplification strategies.

Inhibitory effects and reactions of gallic acid, catechin, and procyanidin B2 with nitrosation under stomach simulating conditions.

Nitrite widely exists in meat products, and has the functions of bacteriostasis, antisepsis, and color development. However, in an acidic environment, nitrite will react with amines, and further generate nitrosamines with carcinogenic and teratogenic effects. Polyphenols have good antioxidant and nitrite-scavenging effects. This study aimed to evaluate the inhibitory effects of gallic acid, catechin, and procyanidin B2 on the nitrosation reaction under stomach simulating conditions and discuss the potential inhibitory mechanism. The nitrite scavenging rate and nitrosamine synthesis blocking rate of gallic acid, catechin, and procyanidin B2 under different reaction times and contents was determined by UV-vis spectrophotometry. The possible products of the reaction of the three polyphenols with nitrite were analyzed by high-performance liquid chromatography-mass spectrometry (HPLC-MS) to reveal the mechanism of inhibiting nitrification. The results showed that the scavenging rate of the three polyphenols on nitrite and the blocking rate of nitrosamine synthesis increased with the increase of the content and reaction time. The ability of the three polyphenols to inhibit nitrosation was catechin > procyanidin B2 > gallic acid. HPLC-MS analysis showed that under simulated gastric juice conditions, the three phenolics were oxidized by nitrous acid to form their semiquinone radicals as the intermediates and nitrosated derivatives, while nitrite might be converted to ˙NO. These results suggested that gallic acid, catechin, and procyanidin B2 could inhibit nitrosation reactions in an acidic environment and may be used as food additives to reduce nitrite residues and nitrosamines in food.

Recent advances in the authentication (geographical origins, varieties and aging time) of tangerine peel (Citri reticulatae pericarpium): A review.

The consumption of tangerine peel (Citri reticulatae pericarpium, CRP) has been steadily increasing worldwide due to its proven health benefits and sensory characteristics. However, the price of CRP varies widely based on its origin, variety, and aging time, which has led many manufacturers to offer inferior products by exploiting the sensory similarity of CRP, seriously undermining consumers' interests. Therefore, it is essential to identify the authenticity of the CRP. In this study, the research progress on the authenticity of CRP from different origins, years and varieties over the past 10 years and the application and prospects of the main technologies and techniques were reviewed. The advantages and disadvantages of the commonly used methods were also summarized and compared. Mass spectrometry-based and spectroscopy-based techniques are the most commonly used methods for analyzing CRP authenticity. However, designing fast, non-destructive and green methods for identifying CRP authenticity would be the future trend.

Formation mechanism of lipid-derived volatile flavor compounds metabolized by inoculated probiotics and their improving effect on the flavor of low-salt dry-cured mackerel.

This study aimed to evaluate the contribution and mechanisms of Lactobacillus plantarum and Zygosaccharomyces mellis inoculation to the enhancement of aroma in low-salt dry-cured mackerel (LDCM). Inoculating probiotics significantly improved the LDCM's aroma, with mixed probiotics showing a superior effect. The contents of lipid-derived volatile flavor compounds (LVFCs), free fatty acid contents, and key enzyme activities significantly increased (p < 0.05) in probiotic-treated groups. The dominant species in the probiotics-treated groups were the inoculated Lactobacillus plantarum and Zygosaccharomyces mellis, which were the main producer of metabolic enzymes for the generation of LVFCs. Lactobacillus plantarum performed well in lipid hydrolysis and aldehydes reduction, while Zygosaccharomyces mellis played a main role in aldehyde production.

Comparing the differences of physicochemical properties and volatiles in semi-dry Hakka rice wine and traditional sweet rice wine via HPLC, GC-MS and E-tongue analysis.

This study aimed to explore effects of indica rice addition, rice soaking time and rice soup addition on total sugar and alcohol content of semi-dry Hakka rice wine (HRW) and compare its difference in physicochemical properties and volatiles with traditional sweet rice wine (TSRW) via HPLC, GC-MS and E-tongue. The optimal fermentation conditions of semi-dry HRW were 50 % indica rice addition, 12 h rice soaking time and 85 % rice soup addition. The total sugar (16.13 mg/mL) of semi-dry HRW was significantly lower than that of TSRW (135.79 mg/mL), especially the trehalose, glucose, sucrose and maltose. Its alcohol content was significantly higher than that of TSRW. There were significant differences in volatile components between semi-dry HRW and TSRW, especially esters, alcohols and ketones, but no significant differences in organic acids and amino acids. Results obtained could provide reference data for improving the fermentation process and quality of semi-dry HRW.

The contribution of inoculated probiotics to increased protein-derived volatile flavor compounds.

This study aimed to evaluate the contribution and mechanisms of Lactobacillus plantarum and Zygosaccharomyces mellis inoculation to the enhancement of protein-derived volatile flavor compounds (PVFCs) in low-salt dry-cured mackerel (LDCM). The contents of PVFCs (3-methylbutanal and phenylacetaldehyde), intermediates (α-ketoisocaproate and phenylpyruvic acid), precursor (α-ketoisocaproate and phenylpyruvic acid), and key enzyme activities (protease and transaminase) significantly increased (p < 0.05) in probiotic-treated groups. The dominant species in the probiotics-treated groups were the inoculated Lactobacillus plantarum and Zygosaccharomyces mellis, which were the main producer of key enzymes for the generation of PVFCs. Lactobacillus plantarum performed well in protein degradation and amino acid transamination, resulting in generating more 3-methylbutanal and phenylacetaldehyde, while Zygosaccharomyces mellis played a main role in phenylethanol production. The synergistic action of Lactobacillus plantarum and Zygosaccharomyces mellis could promote the formation of 3-methyl-1-butanol.

The roles of lipoxygenases and autoxidation during mackerel (Scomberomorus niphonius) dry-cured processing.

The roles of enzymatic (Lipoxygenases, LOX) oxidation and autoxidation in the dry-cured processing of mackerel were investigated by adding exogenous substances in this study. Four groups, namely control, chlorogenic acid (inhibiting LOX activity), EDTA-2Na (inhibiting autoxidation), and exogenous LOX (adding eLOX), were assigned. The results showed that lipid oxidation of mackerel was reduced by inhibiting LOX activity and autoxidation, while adding eLOX promoted lipid oxidation. Inhibition of LOX activity and autoxidation suppressed fatty acid accumulation mainly in the air-drying and curing stage, respectively. The total contents of key flavors in the mackerel during dry-cured processing were decreased by inhibiting LOX activity and autoxidation, and the former inhibitory effect was stronger than autoxidation, while it was corresponding increased through adding eLOX, of particular in the later stage of air-drying. Collectively, LOX could promote the flavor formation of the mackerel in the dry-cured processing, which could be applied in the flavor adjustment of aquatic products or some similar fields.

Amelioration of oxidative kidney damage in offspring by maternal trans-fatty acid exposure in mice by secoisolariciresinol diglucoside. / äºšéº»æœ¨é šç´ å¯¹æ¯é¼ åå¼è„‚è‚ªé ¸æš´éœ²è‡´å­ä»£è‚¾æ°§åŒ–æŸä¼¤çš„ä¿æŠ¤ä½œç”¨.

OBJECTIVES: Trans-fatty acids (TFAs), primarily derived from the food industry's production processes, have become a globally recognized public health issue due to the detrimental impact they have on human well-being. Secoisolariciresinol diglucoside (SDG) is a polyphenolic compound derived from flax lignans, possessing antioxidative properties. This study aims to investigate the protective effect of SDG on kidney oxidative damage in offspring of mice caused by maternal exposure to TFA during pregnancy and lactation. METHODS: A total of 30 c57BL/6 female rats were randomly divided into 5 groups: a control group, a TFA-exposed group, a low-(TFA+LSDG) group, a medium-(TFA+MSDG) group, and a high-(TFA+HSDG) group (n=6 in each group). With the exception of the control group, the maternal mice in the remaining 4 groups received a daily oral gavage of TFA at a dosage of 60 mg/(kg·BW) throughout the experimental period. The mothers in the control group were administered physiological saline via oral gavage once daily. Meanwhile, the 3 SDG intervention groups were provided with ad libitum access to SDG feed containing 10 mg/kg (low), 20 mg/kg (medium), and 30 mg/kg (high) of SDG. The female mice were conceived overnight. If the vaginal plug appeared in the next morning, the female mice were conceived and included in the experimental stage until the end of the 21th day lactation period. The body weight and kidney mass of offspring were recorded, and the kidney coefficient was calculated. The kidney was detected by HE staining to observe the histopathological changes, and the level of reactive oxidative species (ROS) was detected by fluorescence probe-dihydroethidium (DHE) staining; the expression levels of total superoxide dismutase (T-SOD) and malondialdehyde (MDA) in renal homogenate were detected, and the expression of nuclear factor E2-related fator2 (Nrf2) and hemeoxygenase-1 (HO-1) protein was analyzed by immunohistochemistry (IHC) staining. The mRNA expressions of Nrf2 and HO-1 were detected by real-time PCR, and the protein expression of Cu/Zn-superoxide dismutase (Cu/Zn-SOD), Mn-superoxide dismutase (Mn-SOD), glutathione peroxidase-1 (GPx-1), Nrf2 and HO-1 were detected by Western blotting. RESULTS: Compared with the control group, the kidney coefficient in the TFA-exposed group was increased, the morphology and structure of kidney tissue was abnormal; the activity of T-SOD enzyme was decreased, and the content of MDA was increased, the level of ROS was increased; the expressions of Cu/Zn-SOD, Mn-SOD, GPx1 protein were decreased, and the mRNA and protein expressions of Nrf2 and HO-1 were decreased, there were all significant difference (all P<0.05). Compared with the TFA-exposed group, the ROS levels were reduced, and the T-SOD enzyme activity as well as the protein expression of Cu/Zn-SOD, GPx-1, Mn-SOD, Nrf2 and HO-1 were up-regulated in the low, middle and high dose SDG intervention groups; the kidney coefficient and MDA content were decreased in the middle and high dose SDG groups; the Nrf2 mRNA expression in the high dose SDG group was up-regulated, there were all significant difference (all P<0.05). CONCLUSIONS: Maternal exposure to TFA during pregnancy and lactation can lead to oxidative damage in the kidney of offspring, and the SDG intervention may alleviate TFA-induced oxidative damage by up-regulating the expression of Nrf2 and HO-1 signal pathway.

Comparison Study of the Physicochemical Properties, Amino Acids, and Volatile Metabolites of Guangdong Hakka Huangjiu.

The physicochemical properties, amino acids, and volatile metabolites of 20 types of Guangdong Hakka Huangjiu were systematically compared in this study. Lower sugar contents were detected in LPSH, ZJHL-1, and GDSY-1, but the total sugar contents of the other types of Guangdong Hakka Huangjiu were more than 100 g/L (which belonged to the sweet type). Among them, a lower alcohol content was found in GDSY-1 (8.36 %vol). There was a significant difference in the organic acid and amino acid composition among the 20 Guangdong Hakka Huangjiu samples, especially the amino acid composition. However, bitter amino acids as the major amino acids accounted for more than 50% of the total amino acids. A substantial variation in volatile profiles was also observed among all types of Guangzhou Hakka Huangjiu. Interestingly, MZSK-1 had different volatile profiles from other Guangzhou Hakka Huangjiu samples. According to gas chromatography olfactometry (GC-O), most of the aroma-active ingredients identified in Guangdong Hakka Huangjiu were endowed with a pleasant aroma of "fruity".

Characterization and Correlation of Microbiota and Higher Alcohols Based on Metagenomic and Metabolite Profiling during Rice-Flavor Baijiu Fermentation.

Higher alcohol, as an inevitable product of fermentation, plays an important role in the flavor and quality of Baijiu. However, the relationship between the complex microbial metabolism and the formation of higher alcohols in rice-flavor Baijiu was not clear. To investigate the relationship between microorganisms and higher alcohol production, two fermentation mashes inoculated with starters from Heyuan Jinhuangtian Liquor Co., Ltd. (Heyuan, China) as JM and Guangdong Changleshao Co., Ltd. (Meizhou, China) as CM, respectively, with significant differences in higher alcohol profiles during rice-flavor Baijiu fermentation were selected. In general, higher alcohols presented a rapid accumulation during the early fermentation stages, especially in JM, with higher and faster increases than those in CM. As for their precursors including amino acids, pyruvic acid and ketoacids, complex variations were observed during the fermentation. Metagenomic results indicated that Saccharomyces cerevisiae and Rhizopus microsporus were the microorganisms present throughout the brewing process in JM and CM, and the relative abundance of R. microsporus in JM was significantly higher than that in CM. The results of higher alcohol metabolism in JM may contribute to the regulation of higher alcohols in rice-flavor Baijiu.

Formation of Lipid-Derived Flavors in Dry-Cured Mackerel (Scomberomorus niphonius) via Simulation of Autoxidation and Lipoxygenase-Induced Fatty Acid Oxidation.

In this study, lipoxygenase (LOX) extracted from dry-cured mackerel was purified, resulting in a 4.1-fold purification factor with a specific activity of 493.60 U/min·g. LOX enzymatic properties were assessed, referring to its optimal storage time (1-2 days), temperature (30 °C), and pH value (7.0). The autoxidation and LOX-induced oxidation of palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:2n9c), linoleic acid (C18:2n6c), arachidonic acid (C20:4), EPA (C20:5), and DHA (C22:6n3) were simulated to explore the main metabolic pathways of key flavors in dry-cured mackerel. The results showed that the highest LOX activity was observed when arachidonic acid was used as a substrate. Aldehydes obtained from LOX-treated C18:1n9c and C18:2n6c oxidation, which are important precursors of flavors, were the most abundant. The key flavors in dry-cured mackerel were found in the oxidative products of C16:0, C18:0, C18:1n9c, C18:2n6c, and C20:4. Heptanaldehyde could be produced from autoxidation or LOX-induced oxidation of C18:0 and C18:1n9c, while nonal could be produced from C18:1n9c and C18:2n6c oxidation. Metabolic pathway analysis revealed that C18:1n9c, C18:2n6c, EPA, and DHA made great contributions to the overall flavor of dry-cured mackerel. This study may provide a relevant theoretical basis for the scientific control of the overall taste and flavor of dry-cured mackerel and further standardize its production.

The dynamics of physicochemical properties, microbial community, and flavor metabolites during the fermentation of semi-dry Hakka rice wine and traditional sweet rice wine.

The dynamics of physicochemical properties, microbial community and flavor metabolites during fermentation of two typical Hakka rice wine were investigated. Results showed that total sugar content was 136.83 g/L in sweet rice wine, which almost 8 times higher than that in semi-dry rice wine. Its amino acid contents especially bitterness amino acids were also higher than those in semi-dry rice wine. Most organic acids in Hakka rice wine had the tendency of increase in initial stage of fermentation, following a decrease and finally being almost stable. A total of 131 volatiles including esters, alcohols, aldehydes, acids, ketones were detected. Pediococcus, Bacillus, Acinetobacter, Pantoea, Enterobacter and Lactobacillus were the dominant bacterial genera and Monascus, Saccharomyces, Rhizopus were the dominant fungal genera, which are strongly associated with the significant changes in flavor metabolites during Hakka rice wine fermentation. The obtained findings provided reference data for the optimization of Hakka rice wine fermentation.

The dynamic changes of flavors and UPLC-Q-Exactive-Orbitrap-MS based lipidomics in mackerel (Scomberomorus niphonius) during dry-cured processing.

Dry-cured mackerel is favored by consumers for its suitable salty flavor. Herein, the dynamic changes of volatile compounds and lipids in the mackerel, and the lipidomics based on UPLC-Orbitrap/MS technique during dry-cured processing were investigated. The results showed that endogenous lipases activities in dry-cured mackerel decreased. The dry-cured processing of mackerel had significant effects on its lipid classes and content. The contents of Arachidonic acid (C20:4n6), docosapentaenoic acid (C22:5n3), linoleic acid (LA, C18:2n6), alpha-linolenic acid (C18:3n3), eicosatrienoic acid (C20:3n3) and docosahexaenoic acid (DHA, C22:6n3) increased during dry-cured processing. A total of 38 kinds of volatile compounds were detected in the dry-cured mackerel, 12 of which were derived from fatty acid oxidation. Among 30 lipid metabolites (FC ≥ 2 and VIP > 2), phosphatidylethanolamine (PE, 19:0/22:6) accounted for the highest content, and its difference between three stages was the most obvious. Glycerophospholipid and sphingolipid metabolisms were the most important metabolic pathways involved in dry-cured processing.

CMP Pad Conditioning Using the High-Pressure Micro-Jet Method.

In this study, in order to improve and restore the performance of the polishing pads and reduce the cost of chemical mechanical polishing, three types of material polishing pads, namely, polyurethane, damping cloth, and non-woven fabric, were selected for the experiment. Accordingly, each polishing pad was set up with diamond conditioner and high-pressure micro-jet (HPMJ) conditioning control experiments. Subsequently, the fluctuation ranges of the material removal rate on the three polishing pads were 2.73-3.75 µm/h, 1.38-1.99 µm/h, and 2.36-4.32 µm/h, respectively under the HPMJ conditioning method, while the fluctuation ranges of the material removal rate on the three polishing pads were 1.80-4.14 µm/h, 1.02-2.09 µm/h, and 1.78-5.88 µm/h under the diamond conditioning method. Comparing the polishing pad morphologies under SEM, we observed that the surface of the polishing pad after HPMJ conditioning was relatively clean, and the hole structure was not blocked. Contrastingly, there remained numerous abrasive particles on the surface after the conventional diamond conditioning and the hole structure was blocked. Thus, the HPMJ conditioning technology is better than the traditional diamond conditioning technology. Subsequently, the polishing pad after HPMJ conditioning has a longer service life and a more stable material removal rate than that after traditional diamond conditioning.

Monitoring the variations in physicochemical characteristics of squab meat during the braising cooking process.

Braised squabs are traditional Chinese foods. However, the processing is highly experience dependent and lacks a theoretical basis. Hence, a comparative study of the physicochemical properties in different processing stages of braised squabs was necessary. We observed the physicochemical changes in the processing stages of braised squabs (raw meat, braised meat, and fried meat). The color parameters, moisture content, and drip loss rate gradually decreased during the processing. On the contrary, crude protein content and pH value were upregulated in the processing stages of braised squabs. Furthermore, the diameter of muscle fiber significantly increased in the braised meat and further decreased in the fried meat compared with the raw muscle fiber. Similarly, hardness, springiness, and chewiness were also increased in the braised step and decreased in the fried step. Additionally, the contents of essential amino acids remain unchanged. Hence, our results provided a certain reference value on the production of braised squabs.

Family carers' expectations regarding dementia care services and support in China: A qualitative study.

INTRODUCTION: In China, approximately 85% of people with dementia are cared for by family carers. However, limited research has been conducted to examine family carers' expectations regarding what they perceive is required for optimal care. Therefore, this study aimed to explore family carers' expectations regarding dementia care support and services in China. METHODS: A qualitative study employing semi-structured interviews, with data collected from three public tertiary hospitals where the primary family carers of people with dementia (N = 21) were recruited from May to December 2019. Purposive maximum variation sampling was used to recruit participants. Data was interpreted both inductively and deductively using thematic analysis. FINDINGS: Four themes were identified. The family carers reported minimal support regarding dementia care, and they held little hope of receiving support. However, most carers expressed their limited expectations, such as financial support from the government and respite care services from the community. Carers believed that care was their duty, and some of them were unwilling to move their relative with dementia into a nursing home. CONCLUSION: Health and the three-tier long-term care systems in China are inadequately prepared for the challenges of dementia care, suggesting the need to develop health and social services and improve support for family carers to enable improved care for people with dementia.

Effects of pH Values and H2O2 Concentrations on the Chemical Enhanced Shear Dilatancy Polishing of Tungsten.

In order to obtain tungsten with great surface qualities and high polishing efficiency, a novel method of chemical enhanced shear dilatancy polishing (C-SDP) was proposed. The effects of pH values and H2O2 concentrations on the polishing performance of tungsten C-SDP were studied. In addition, the corrosion behaviors of tungsten in solutions with different pH values and H2O2 concentrations were analyzed by electrochemical experiments, and the valence states of elements on the tungsten surface were analyzed by XPS. The results showed that both pH values and H2O2 concentrations had significant effects on tungsten C-SDP. With the pH values increasing from 7 to 12, the MRR increased from 6.69 µm/h to 13.67 µm/h. The optimal surface quality was obtained at pH = 9, the surface roughness (Ra) reached 2.35 nm, and the corresponding MRR was 9.71 µm/h. The MRR increased from 9.71 µm/h to 34.95 µm/h with the H2O2 concentrations increasing from 0 to 2 vol.%. When the concentration of H2O2 was 1 vol.%, the Ra of tungsten reached the lowest value, which was 1.87 nm, and the MRR was 26.46 µm/h. This reveals that C-SDP technology is a novel ultra-precision machining method that can achieve great surface qualities and polishing efficiency of tungsten.