Pyruvic Acid Content Research Articles

Inactivation kinetics of Bacillus cereus and Aspergillus niger spores in dehydrated onion shreds after pulsed light and infrared treatments

Fresh onions are dehydrated to increase their shelf-life. Primarily, open dehydration techniques like solar dehydration come with the problem of contamination through natural air convection. A solar conduction dryer that uses conduction, convection, and radiation for dehydration of food samples is exploited in this study. The food samples are often contaminated by Bacillus and Aspergillus species spores. As a remedy, pulsed light treatment as a non-thermal technology and infrared treatment as a thermal technology are studied and compared. Bacillus cereus and Aspergillus niger spores are chosen as a representative of bacterial and fungal contamination in onions. Dehydrated onion shreds with varying water activities (0.4, 0.5, 0.6) were treated. The spore inactivation was best described by Weibull model as compared with first-order model. Scanning electron microscopy images of the microbial cells showed surface distortions on the bacterial and fungal spores. The effect of the treatment technologies on the colour, flavour (thiosulphinate and pyruvic acid concentration), total phenolic and flavonoid content, and ascorbic acid concentration are compared. Overall, pulsed light treatment showed promising inactivation with a maximum log reduction of 4.5 log B. cereus spores·g−1 and 3.1 log A. niger spores·g−1 at 2.131 J·cm−2 in samples with water activity 0.6. The inactivation rate increased with an increase in water activity. The colour was better retained in pulsed light treated samples. The thiosulphinate content (9.24 μmol·g−1), total phenolics (0.268 mg GAE·g−1), and flavonoid content (0.344 mg QE·g−1) in the sample were improved upon pulsed light exposure.Graphical

Comparative Metabolome and Transcriptome Analysis of Rapeseed (Brassica napus L.) Cotyledons in Response to Cold Stress.

Cold stress affects the seed germination and early growth of winter rapeseed, leading to yield losses. We employed transmission electron microscopy, physiological analyses, metabolome profiling, and transcriptome sequencing to understand the effect of cold stress (0 °C, LW) on the cotyledons of cold-tolerant (GX74) and -sensitive (XY15) rapeseeds. The mesophyll cells in cold-treated XY15 were severely damaged compared to slightly damaged cells in GX74. The fructose, glucose, malondialdehyde, and proline contents increased after cold stress in both genotypes; however, GX74 had significantly higher content than XY15. The pyruvic acid content increased after cold stress in GX74, but decreased in XY15. Metabolome analysis detected 590 compounds, of which 32 and 74 were differentially accumulated in GX74 (CK vs. cold stress) and XY15 (CK vs. cold stressed). Arachidonic acid and magnoflorine were the most up-accumulated metabolites in GX74 subjected to cold stress compared to CK. There were 461 and 1481 differentially expressed genes (DEGs) specific to XY15 and GX74 rapeseeds, respectively. Generally, the commonly expressed genes had higher expressions in GX74 compared to XY15 in CK and cold stress conditions. The expression changes in DEGs related to photosynthesis-antenna proteins, chlorophyll biosynthesis, and sugar biosynthesis-related pathways were consistent with the fructose and glucose levels in cotyledons. Compared to XY15, GX74 showed upregulation of a higher number of genes/transcripts related to arachidonic acid, pyruvic acid, arginine and proline biosynthesis, cell wall changes, reactive oxygen species scavenging, cold-responsive pathways, and phytohormone-related pathways. Taken together, our results provide a detailed overview of the cold stress responses in rapeseed cotyledons.

Biological features and quality comprehensive analysis of twelve germplasm resources of the genus Allium from Tibet.

Allium is important vegetables and seasonings in China, Tibet is rich in unique resources of the genus Allium, but lacks development and utilization. We compared the biological features and comprehensively evaluating the quality of twelve germplasm resources of the genus Allium collected from Tibet. The results revealed that nine germplasm resources were bolting and bloom normally except for SC015, SC019, and SC048, all twelve germplasm resources were able to vegetative growth. The individual differences in moisture, soluble sugar, and protein content among the twelve germplasm resources were relatively small, with pyruvic acid content ranging from 0.11 to 1.12 mg/g and a large variation coefficient. A total of 8 categories and 97 volatile compounds were detected in twelve germplasm resources, the majority possessed the highest proportions of aldehydes and organosulfur compounds, but there were certain differences between the different Allium species. Additionally, 11 to 16 types of free amino acids were present in all germplasm resources, proline exhibited the highest content. The total content of essential and non-essential amino acids in SC009 was the highest. Carbon (C) accounted for the largest proportion of all elements, and the contents of other mineral elements varied greatly among the different plants. In conclusion, combined with biological performance and comprehensive evaluation of quality, SC009 is the excellent germplasm resource suitable for growth and capable of reproduction with good quality. These results improved the exploitation and utilization of the genus Allium in Tibet, as well as provided germplasm resources for high-quality breeding of the genus Allium.

Efficacy and mechanism of energy metabolism dual-regulated nanoparticles (atovaquone-albendazole nanoparticles) against cystic echinococcosis

BackgroundAlbendazole (ABZ) and atovaquone (ATO) achieve killing efficacy on Echinococcus granulosus (Egs) by inhibiting energy metabolism, but their utilization rate is low. This study aims to analyze the killing efficacy of ABZ-ATO loading nanoparticles (ABZ-ATO NPs) on Egs.MethodsPhysicochemical properties of NPs were evaluated by ultraviolet spectroscopy and nanoparticle size potentiometer. In vitro experiments exmianed the efficacy of ATO, ABZ, or ATO-ABZ NPs on protoscolex activity, drug toxicity on liver cell LO2, ROS production, and energy metabolism indexes (lactic dehydrogenase, lactic acid, pyruvic acid, and ATP). In vivo of Egs-infected mouse model exmianed the efficacy of ATO, ABZ, or ATO-ABZ NPs on vesicle growth and organ toxicity.ResultsDrug NPs are characterized by uniform particle size, stability, high drug loading, and − 21.6mV of zeta potential. ABZ or ATO NPs are more potent than free drugs in inhibiting protoscolex activity. The protoscolex-killing effect of ATO-ABZ NPs was stronger than that of free drugs. In vivo Egs-infected mice experiment showed that ATO-ABZ NPs reduced vesicle size and could protect various organs. The results of energy metabolism showed that ATO-ABZ NPs significantly increased the ROS level and pyruvic acid content, and decreased lactate dehydrogenase, lactic acid content, and ATP production in the larvae. In addition, ATO-ABZ NPs promoted a decrease in DHODH protein expression in protoscolexes.ConclusionATO-ABZ NPs exhibits anti-CE in vitro and in vivo, possibly by inhibiting energy production and promoting pyruvic acid aggregation.

Distinct metabolomic and lipidomic profiles in serum samples of patients with primary sclerosing cholangitis.

Identification of specific metabolome and lipidome profile of patients with primary sclerosing cholangitis (PSC) is crucial for diagnosis, targeted personalized therapy, and more accurate risk stratification. Nuclear magnetic resonance (NMR) spectroscopy revealed an altered metabolome and lipidome of 33 patients with PSC [24 patients with inflammatory bowel disease (IBD) and 9 patients without IBD] compared with 40 age-, sex-, and body mass index (BMI)-matched healthy controls (HC) as well as 64 patients with IBD and other extraintestinal manifestations (EIM) but without PSC. In particular, higher concentrations of pyruvic acid and several lipoprotein subfractions were measured in PSC in comparison to HC. Of clinical relevance, a specific amino acid and lipid profile was determined in PSC compared with IBD and other EIM. These results have the potential to improve diagnosis by differentiating PSC patients from HC and those with IBD and EIM.

Efficient synthesis of L-malic acid by malic enzyme biocatalysis with CO2 fixation

The malic enzyme (ME) catalyzes the synthesis of L-malic acid (L-MA) from pyruvic acid and CO2 with NADH as the reverse reaction of L-MA decarboxylation. Carboxylation requires excess pyruvic acid, limiting its application. In this study, it was determined that CO2 was the carboxyl donor by parsing the effects of HCO3– and CO2, which provided a basis for improving the L-MA yield. Moreover, the concentration ratio of pyruvic acid to NADH was reduced from 70:1 to 5:1 using CO2 to inhibit decarboxylation and to introduce the ME mutant A464S with a 2-fold lower Km than that of the wild type. Finally, carboxylation was coupled with NADH regeneration, resulting in a maximum L-MA yield of 77 % based on the initial concentration of pyruvic acid. Strategic modifications, including optimal reactant ratios and efficient mutant ME, significantly enhanced L-MA synthesis from CO2, providing a promising approach to the biotransformation process.

Dose-dependent alteration in hepatic and cerebral glucose metabolism following exposure to polystyrene microplastic in Wistar rats

Background: Recently, microplastics (MPs) with dimensions less than 5 mm have gained more attention due to their adverse impact on the environment and living creatures. Polystyrene (PS) particle is a key element of primary microplastics, which are causing numerous health issues such as interruption of energy metabolism, oxidative stress, neurotoxicity, immunotoxicity, digestive gland disorders, reproductive disruption, and genotoxicity in marine living organisms. Method: Alteration in carbohydrate metabolism was evaluated in male Wistar rats (six weeks of age) after four weeks of oral exposure to polystyrene microplastic (PS-MP) at three different doses (0.5mg/L, 5mg/L and 50 mg/L via drinking water). Results: Polystyrene exposure caused a significant decrease in blood glucose, liver glycogen, and pyruvic acid content in liver and cerebral tissue. Free amino nitrogen content significantly altered in the liver and cerebrum in a dose-specific manner. The LDH activity was found to be decreased in the liver, whereas it increased in the cerebral cortex of rats in a dose-responsive fashion. Enzymes like glucose 6-phosphatase, GOT, GPT, and succinate dehydrogenase activities demonstrated differential effects on the liver and cerebrum of rats in terms of energy metabolism. Conclusion: It is suggested that sub-acute polystyrene exposure significantly perturbs glucose metabolism by inducing hypoglycemia associated with decreased glycolysis and increased TCA cycle enzyme function in rat liver in a dose-dependent manner. Gluconeogenesis is also affected differentially by metabolic adjustment in the studied organs.

Serum Metabolomic Profiling of Patients with Lipedema.

Lipedema is a chronic condition characterized by disproportionate and symmetrical enlargement of adipose tissue, predominantly affecting the lower limbs of women. This study investigated the use of metabolomics in lipedema research, with the objective of identifying complex metabolic disturbances and potential biomarkers for early detection, prognosis, and treatment strategies. The study group (n = 25) comprised women diagnosed with lipedema. The controls were 25 lean women and 25 obese females, both matched for age. In the patients with lipedema, there were notable changes in the metabolite parameters. Specifically, lower levels of histidine and phenylalanine were observed, whereas pyruvic acid was elevated compared with the weight controls. The receiver operating characteristic (ROC) curves for the diagnostic accuracy of histidine, phenylalanine, and pyruvic acid concentrations in distinguishing between patients with lipedema and those with obesity but without lipedema revealed good diagnostic ability for all parameters, with pyruvic acid being the most promising (area under the curve (AUC): 0.9992). Subgroup analysis within matched body mass index (BMI) ranges (30.0 to 39.9 kg/m2) further revealed that differences in pyruvic acid, phenylalanine, and histidine levels are likely linked to lipedema pathology rather than BMI variations. Changes in low-density lipoprotein (LDL)-6 TG levels and significant reductions in various LDL-2-carried lipids of patients with lipedema, compared with the lean controls, were observed. However, these lipids were similar between the lipedema patients and the obese controls, suggesting that these alterations are related to adiposity. Metabolomics is a valuable tool for investigating lipedema, offering a comprehensive view of metabolic changes and insights into lipedema's underlying mechanisms.

Shaping the chromatic characteristics of red wines by using biofilm-detached cells of Starmerella bacillaris strains

The aim of this study was to evaluate the effects of 10 Starmerella bacillaris strains inoculated as planktonic or biofilm-detached cells on the chromatic characteristics of Montepulciano d’Abruzzo wine. Wines inoculated with biofilm-detached cells of St. bacillaris were characterized by a higher content of glycerol and viable yeast cells and a lower content of ethanol than those obtained with planktonic cells. Pyruvic acid content ranged from 45.99 mg/L to 48.19 mg/L and from 41.13 mg/L to 45.9 mg/L in wines fermented with biofilm-detached and planktonic cells, respectively. Wines obtained with biofilm-detached cells showed levels of anthocyanins ranging from 506.8 mg/L to 659.9 mg/L, while those fermented with free cells of St. bacillaris ranged from 518 mg/L to 612.6 mg/L. Similarly, the content of polyphenols was higher in wines inoculated with biofilm-detached cells. The different amounts of these compounds resulted in differences in the wine's color. Wines obtained with biofilm-detached cells of St. bacillaris had lower b* and h* values than those obtained with planktonic cells. These wines also showed higher a* values, indicating the presence of a stronger red color than the others, and lower clarity (L*). Moreover, the data obtained highlighted that it is possible to predict the color of young wines from must measurements. Further studies will be done to evaluate the role of other non-Saccharomyces yeasts, grown under different aggregation states, in the definition of wine color.

Papaia fermentada: estratégias para monitorizar e melhorar a fermentação das amostras - estudo preliminar

Introduction: Fermented papaya is known as a nutraceutical, with a unique composition and several health benefits. Its fermentation, being a central process of metabolism, converts the sugars in the fruit into alcohols or acids, with the intermediate formation of pyruvic acid. However, there is a lack of control and uniformity in terms of processes. Objectives: Carry out fermentation cycles of papaya in order to determine which conditions contribute to improving the pyruvic acid content and verify if there is any change of it after freezing preservation. Methodology: The papaya was washed with distilled water and cut into small cubes. About a quarter of each fruit was divided into two sterile flasks, adding ultrapure water, and placing it at 30°C. The flasks were manually shaken every 24 hours, an aliquot was taken for pH measurement. At the end of each fermentation cycle, the sample was subjected to centrifugation followed by gravity filtration and storage at -20°C. At the time of analysis, the aliquots were thawed, and the pH was measured again. The sodium pyruvate content (sodium salt of pyruvic acid) was quantified through a method adapted from another study and validated by this research team. The various fermentation cycles were carried out in duplicate, with changes in the fermentation conditions. Results: The highest content of sodium pyruvate was obtained at the end of the fermentation cycle where the whole fruit (pulp, peel and seeds) was used with sucrose supplementation (1 g.L-1). This indicates that the peel and seeds of papaya, due to their phytochemical composition, have constituents that improve the fermentation process while reducing food waste. The lowest content of sodium pyruvate was obtained on the second day of the fermentation cycle where only fresh papaya pulp and seeds were used, confirming that the presence of the peel is fundamental, probably due to the existence of autochthonous flora in the fruit that contributes to the fermentation process. Furthermore, it was also possible to verify that the pH does not change with the freezing process, indicating that there was no alteration of the pyruvic acid content during the preservation period. Conclusion: It was found that the fermentation conditions that promote a higher content of pyruvic acid is using the whole fruit and sucrose, at 30°C, for 7 days. However, other temperatures, as well as other fermentation conditions, should still be tested in order to understand if the fermentation process can be improved.

Evaluation of Different Genotypes of Late Kharif Onion (Allium cepa L.) Under the Gangetic Plains of West Bengal, India

Aim: Onions, (Allium cepa L.) is one of the highly significant bulbs crops extensively cultivated in India. The investigation entitled “Evaluation of different genotypes of Late Kharif Onion (Allium Cepa L.) under the Gangetic plains of West Bengal”is aimed at suggesting the more locally suitable genotypes to the farmer as well as the researchers.
 Study Design: The experiment was conducted in randomized block design (RBD) with seven genotypes and they were randomized in three replications. This Experiment deals with seven different late kharif onion genotypes which consist of viz. Bhima Shakti, Bhima Kiran, Bhima Raj, DOGR-1605, NHRDF-Red-2, DOGR-1606 and PRO-7.
 Place and Duration of Study: The research investigation was conducted at C-Block farm, Bidhan Chandra Krishi Viswavidyalaya, Kalyani, Nadia, West Bengal during the year 2022- 2023.
 Methodology: 30 days old seedlings were transplanted at 15 cm between lines and 10 cm within it. All other intercultural operations were done as and when necessary. Harvesting of bulbs was done at maturity stage. Biometrical observations and yield attributing characters were recorded from randomly selected 10 plants from each replication and the quality parameters were evaluated from randomly selected 5 plants.
 Results: From the present investigation it was found that the late kharif onion genotype Bhima Shakti emerged with the highest yield (285.80 q-ha) but in terms of other quality parameters the genotype NHRDF-Red-2 found quite good in TSS (14.12 ̊ B) and pyruvic acid content of (6.24 µmol-g), whereas genotypes Bhima Raj, exhibits lowest total sugar of (2.40 %) and reducing sugar of (2.13%).
 Conclusion: Although from the above experiment it may be concluded that in case of late kharif onion genotypes the genotypes Bhima Shakti, Bhima Raj and NHRDF-Red-2 performed well.

Growth and Quality Profiency of Onion (Allium cepa L.) by Application of Biofertilizer, GA3 and Humic Acid

During the Rabi season in 2022-2023, a comprehensive trial was carried out at the Department of Horticulture, Jawaharlal Nehru Krishi Vishwa Vidyalaya. Employing a Randomized Completely Block Design (RCBD), the research assessed twelve different interventions, consisting of biofertilizers, GA3, humic acid and a reference group. Notably, the combined application of Azotobacter, Azospirillum, GA3 and humic acid (T10) showcased substantial improvements in several growth parameters. These encompassed plant height (62.23 cm), number of leaves (10.18), length of leaves (54.08 cm), leaf area (624.65 cm²), leaf area index (4.16) and leaf diameter (8.14 mm). Additionally, this treatment recorded the highest Total Soluble Solids (TSS) at 12.37 °Brix. Moreover, the inclusion of sulphur and humic acid significantly affected the pyruvic acid content, with T10 recorded the highest pyruvate values (5.28 µmol/g). Conversely, the reference group (T12) only recorded slight improvements, emphasizing the noteworthy impact of the interventions on both the growth and qualitative characteristics of the onions.

Mepiquat chloride increases Cry1Ac protein content by regulating the carbon and amino acid metabolism of Bt cotton under high temperature and drought stress

The effects of mepiquat chloride (DPC) on Cry1Ac protein contents in Bacillus thuringiensis (Bt) cotton boll shells under high temperature and drought stress were investigated to provide a theoretical reference for Bt cotton breeding and high-yield and high-efficiency cotton cultivation. This study was undertaken on the Bt cotton cultivar ‘Sikang 3’ during the 2020 and 2021 growing seasons at Yangzhou University Farm, Yangzhou, China. The potted cotton plants were exposed to high temperature and drought stress, and 20 mg L−1 DPC and water (CK) were sprayed on cotton plants. Seven days after treatment, Cry1Ac protein content, α-ketoglutarate content, pyruvic acid content, glutamate synthase activity, glutamic oxaloacetic transaminase activity, soluble protein content, and amino acid content were measured, and transcriptome sequencing was performed. DESeq was used for differential gene analysis. Under the DPC treatment, in contrast with the water treatment (CK), Cry1Ac protein content increased by 4.7-11.9%. α-Ketoglutarate content, pyruvic acid content, glutamate synthase activity, glutamic oxaloacetic transaminase activity, soluble protein content, and amino acid content all increased. Transcriptome analysis revealed that there were 7542 upregulated genes and 10449 downregulated genes for DPC vs. CK. GO and KEGG analyses showed that differentially expressed genes were mainly involved in biological processes, such as amino acid metabolism and carbon metabolism. Genes coding 6-phosphofructokinase, pyruvate kinase, glutamic pyruvate transaminase, pyruvate dehydrogenase, citrate synthase, isocitrate dehydrogenase, 2-oxoglutarate dehydrogenase, glutamate synthase, 1-pyrroline-5-carboxylate dehydrogenase, glutamic oxaloacetic transaminase, amino-acid N-acetyltransferase, and acetylornithine deacetylase were all significantly upregulated. DPC increased pyruvate, α-ketoglutarate, and oxaloacetate by increasing the operating rate of the glycolytic pathway, the citric acid cycle. It also significantly up-regulated the genes encoding glutamate synthase and pyrrolidine-5-carboxylic acid dehydrogenase, and down-regulated the genes encoding glutamine synthetase as well as up-regulated the genes encoding glutamate oxaloacetate transaminase and N-acetylglutamate synthetase. Therefore, the synthesis ability of aspartic acid, glutamic acid, pyruvate, and arginine was increased by DPC, and then Cry1Ac protein contents were increased by regulating carbon and amino acid metabolism.

Changes in metabolite content in the kidneys and skeletal muscles of rats fed magnesium-restricted diets

A metabolomic study was performed on the kidneys and skeletal muscles of rats fed diets containing varying contents of Mg for 4 weeks. The kidneys are divided into two parts, the aerobic cortex and the anaerobic medulla, that differ in metabolism. The relative contents of 3-phosphoglyceric acid, 2-phosphoglyceric acid, and phosphoenolpyruvic acid increased with Mg restriction in both renal regions. In contrast, pyruvic acid content decreased with Mg restriction in the diets, suggesting an inhibitory conversion of phosphoenolpyruvic acid to pyruvic acid. The lactic acid content increased in both regions of the kidneys of Mg-restricted rats, implying changes towards a more glycolytic metabolism, possibly resulting from the impairment of mitochondrial function. There are two types of muscle fibers: glycolytic fast and oxidative slow muscle fibers. The soleus muscle consists of slow muscle fibers, whereas the gastrocnemius muscle consists of a combination of fast and slow muscle fibers. Similar to the changes in the kidneys, the contents of 3-phosphoglyceric acid, 2-phosphoglyceric acid, phosphoenolpyruvic acid, and lactic acid increased in the soleus and gastrocnemius muscles with dietary Mg restriction. Unlike in the kidney, pyruvic acid content increased in the soleus muscle in response to Mg restriction. Severe Mg restriction decreased contents of carnosine and its constituent β-alanine and increased the levels of purine derivatives such as xanthine and uric acid in the gastrocnemius muscle. The present study suggests a region-dependent sensitivity to dietary restriction of Mg, which may lead to the onset of various metabolic disorders.

Diagnostic significance of antioxidant protection indicators for assessing the course of post-Covid syndrome

Introduction. An increasing number of reports of long-term negative consequences of COVID-19, characterized by chronic inflammation, tissue hypoxia, oxidative stress, metabolic changes at the level of all body systems, determines the search for criteria for assessing long-term post-Covid syndrome. A high level of information content of saliva as samples for laboratory diagnosis of respiratory syndromes has been shown. The fact that SARS-CoV-2 is present in saliva in high concentrations suggests that saliva studies will provide rapid acquisition of useful information about the pathogenesis of post-Covid syndrome, allows us to identify the most vulnerable areas of metabolic processes and target them in combination with other rehabilitation measures. Purpose of the study: to evaluate the state of antioxidant protection and indicators of resistance to hypoxia in patients in the post-Covid period 6 monthes after the manifestation of the infectious process caused by SARS-CoV-2, according to biochemical analysis of saliva. Material and methods. 58 people participated in the study. 28 people – control group, who denied the fact of the disease; 30 people – a comparison group who suffered a new coronavirus infection of moderate severity, confirmed by PCR. The concentrations of pyruvic acid, lactic acid, reduced glutathione, the activity of glutathione reductase, glutathione peroxidase, myeloperoxidase, and ceruloplasmin were determined in saliva. Results. In the saliva of patients in the post-Covid period, there is a pronounced increase in myeloperoxidase activity, which indicates a chronic inflammatory process. An increase in ceruloplasmin activity indicates a deficiency of iron and copper, which are necessary for oxidative phosphorylation and cellular respiration. A change in the ratio of lactate to pyruvate indicates the accumulation of NАDН2, so to change the Redox status of the body, characteristic of hypoxic conditions. A decrease in the activity of enzymes of the glutathione system was noted, which reflects the inhibition of the processes of AOD and mitochondrial oxidation. Conclusion. A set of indicators characterizing AOD, the ratio of aerobic and anaerobic processes, iron and copper transport, provides information about the peculiarities of the course of the post-Covid syndrome, which substantiates the correction paths associated with restoring glutathione levels, indicators of iron and copper metabolism and increasing resistance to hypoxic processes.

Changes in quality attributes of pulsed light treated dehydrated onion shreds during storage

Processing of dehydrated onion shreds involves contamination during peeling, chopping, and dehydration. Pre-treatments such as blanching, dipping and soaking in chemical solutions reduce the contamination prior to dehydration. Post dehydration treatments include thermal and non-thermal technologies. Hot water blanching in presence of CaCl2 as pre-treatment followed by pulsed light of 2208 ± 0.5 J·cm−2 (2100 V, 120 s) as post-dehydration treatment is employed. Further, the microbial quality and other attributes were assessed during the storage at 25, 30, and 37 °C. The population for aerobic mesophiles and yeasts & molds crossed 5 and 4 log CFU∙g−1, respectively after 30, 27, 19 days of storage at 25, 30, and 37 °C, respectively. Browning index, pyruvic acid, total phenols and flavonoids were most sensitive among the color parameters and bioactive compounds degraded during storage. After 30 days of storage at 25 °C, there was reduction of 82% in ascorbic acid, 39% in pyruvic acid, 93% in thiosulphinate, 50% in total phenolics, and 52% in total flavonoids content of the shreds. At 37 °C, the rate of bioactive degradation was higher and the retention in bioactives after 19 days was 24, 56, 35, 35, and 52% of ascorbic acid, pyruvic acid, thiosulphinate, total phenolics, and total flavonoids content, respectively. The pyruvic acid, ascorbic acid, phenolic and flavonoid content in the onion shreds degraded following first order kinetics, whereas thiosulphinates followed zero order degradation. The shelf-life of the pulsed light decontaminated dehydrated onion shreds was 30, 27, 19 days at 25, 30, and 37 °C, respectively. Pulsed light treatment is recommended for dehydrated onion shreds as an effective technology for microbial inactivation.

Elevated O2 alleviated anaerobic metabolism in postharvest winter jujube fruit by regulating pyruvic acid and energy metabolism

Over-accumulation of anaerobic metabolites is a typical characteristic of postharvest senescence in winter jujube fruit. Here, elevated O2 was applied during cold storage to investigate its regulation on anaerobic respiration. The results found 60 % O2 was the optimal concentration to inhibit anaerobic respiration, which showed 83.82 % lower acetaldehyde and 57.13 % lower ethanol compared with control. Elevated O2 maintained energy status by activating succinate dehydrogenase and cytochrome C oxidase, with 1.11-fold higher energy charge observed as compared with the control. In addition, activated aerobic respiration also accelerated the consumption of pyruvic acid, and pyruvic acid content was reduced by 63 % in elevated O2-treated fruit. Sufficient energy supply and reduced pyruvic acid content in elevated O2-treated fruit induced the alleviation of anaerobic respiration, leading to attenuating the accumulation of ethanol and acetaldehyde as a result. The study proved elevated O2 repressed anaerobic metabolism by regulating pyruvic acid level and energy metabolism.

Metabolomic study on the quality differences and physiological characteristics between rice cultivated in drought and flood conditions

The differences between dry- and flood-cultivated rice and the reason behind low-quality dry-cultivated rice were clarified. The physiological traits, starch synthase activity, and grain metabolomics of ‘Longdao 18′ were measured and analyzed at four growth stages. The brown, milled, and whole-milled rice rates and AGPase, SSS, and SBE activity were lower after drought treatment than during flood cultivation, while the chalkiness, chalky grain rate, amylose (16.57–20.999%), protein (7.99–12.09%), and GBSS activity were higher. Related enzymatic gene expression showed significant differences. Metabolic results showed pyruvate, glycine, and methionine upregulation at 8DAF and higher citric, pyruvic, and α-ketoglutaric acid content at 15DAF. Therefore, 8DAF-15DAF represented the crucial quality formation period for dry-cultivated rice. At 8DAF, the respiratory pathways used amino acids as signaling molecules and alternative substrates to adapt to energy shortages, arid environments and rapid protein accumulation and synthesis. Excessive amylose synthesis at 15DAF accelerated reproductive growth, promoting rapid premature aging.

The mechanism of whey protein and blueberry juice mixed system fermented with Lactobacillus inhibiting Escherichia coli during storage

The aim of this study was to identify the antimicrobial effect and mechanism of whey protein and blueberry juice mixed systems fermented with Lactobacillus against Escherichia coli during storage. The whey protein and blueberry juice mixed systems were fermented with L. casei M54, L. plantarum 67, S. thermophiles 99 and L. bulgaricus 134 and had different antibacterial activities against E. coli during storage. The antimicrobial activity of the mixed whey protein and blueberry juice mixture systems was the highest, with an inhibition zone diameter of approximately 230 mm, compared with the whey protein or blueberry juice systems alone. There were no viable E. coli cells 7 h after treatment with of the whey protein and blueberry juice mixed systems as determined by survival curve analysis. Analysis of the inhibitory mechanism showed that the release of alkaline phosphatase, electrical conductivity, protein and pyruvic acid contents, and aspartic acid transaminase and alanine aminotransferase activity in E. coli increased. These results demonstrated that these mixed systems fermented with Lactobacillus, especially those containing blueberries, could inhibit the growth of E. coli and even cause cell death by destroying the cell membrane and cell wall.

Role of aerosol liquid water content on the production of dicarboxylic acids in the dust-laden air masses over the Arabian Sea: Implications for heterogeneous chemistry

Oxalic acid and the related organics are ubiquitous water-soluble constituents of ambient organic aerosols (OA). Their molecular distributions and relative abundances provide crucial insights on the secondary OA formation processes in the marine atmosphere and are important for understanding the cloud-aerosol interactions. Here, we measured the concentrations of dicarboxylic acids, pyruvic acid, ω-oxocarboxylic acids and α-dicarbonyls alongside aerosol chemical composition in the South Asian outflow to the Arabian Sea. Oxalic acid (C2) was the most abundant dicarboxylic acid followed by succinic (C4) and malonic (C3) acids; this distribution is typical of “less aged OA”. Oxalic acid levels correlated well with aerosol liquid water content (ALWC) and non-sea-salt (nss)-SO42− (a tracer of coal combustion influence), suggesting an important aqueous phase oxidation of successive higher homologs. This was inferred based on the prevailing inverse relationships between the relative abundances of oxalic acid in total aliphatic dicarboxylic acids and those of malonic, succinic, glutaric, adipic, and azelaic acids. Likewise, the concentrations of glyoxal (Gly: a major compound emitted from vehicular exhaust) and glyoxylic acid (ωC2) correlated strongly with C4, nss-Ca2+ (dust tracer) and elemental carbon (EC: a combustion tracer from biomass/fossil-fuels). These observations suggest gas/particle partitioning and subsequent aqueous phase oxidation of Gly to ωC2 and then elongation (oligomerization) to succinic acid associated with the mineral dust particles. This means relative abundances of anthropogenic SO42− in the dust-laden air masses govern the secondary OA formation over the Arabian Sea.