Quantitative Analysis of Lactate and Other Organic Acids in Plasma: Preanalytical Challenges

2019 ◽  
Vol 152 (Supplement_1) ◽  
pp. S28-S28
Author(s):  
Irene De Biase ◽  
Bethelhem Almaw ◽  
Bucky Lozier ◽  
Marzia Pasquali ◽  
Tatiana Yuzyuk

Abstract Background and Objectives We developed a gas chromatography–mass spectrometry (GC-MS) method for the analysis of organic acids (OAs) in plasma using liquid-liquid extraction with acidified methanol. This method allows for the simultaneous analysis of several metabolites associated with energy metabolism, including lactic and pyruvic acids. Here, we evaluated the effect of different preanalytical variables (anticoagulants, delayed plasma separation, fasting vs nonfasting status) on plasma organic acid quantitation. Methods Nine organic acids (lactic, pyruvic, 3-hydroxybutyric, acetoacetic, 2-ketoisovaleric, 2-keto-3-methylvaleric, 2-ketoisocaproic, succinic, and glutaric) were extracted by deproteinizing with acidified methanol, oximated to preserve ketoacids, converted to volatile trimethylsilyl derivatives, and detected by GC-MS. Compound identification was obtained by retention time and fragmentation spectra using Agilent MassHunter software. We performed several comparison studies using blood collected from self-reported healthy participants (24-60 years of age; 14 females, 13 males). The effect of fasting/nonfasting status was evaluated in 14 participants by comparing samples collected after overnight fasting and 4 hours after meal. Paired t test was used for the statistical analysis of results. Results When compared to the preferred sample type, sodium heparin (green top) plasma EDTA plasma (purple top, n = 9) and serum (red top or serum separator tube; n = 5) displayed an unacceptable variability for several analytes. The biggest differences were observed for lactic and pyruvic acids. Lactic acid was significantly lower in EDTA plasma (9%-35% decrease; P = .0001), but higher in serum (4%-63% increase; P = .014), while pyruvic acid was significantly higher in EDTA plasma (4%-145% increase; P = .0002). The measurements of lactic and pyruvic acids were also affected by delayed separation of plasma in samples kept at room temperature. We observed a marked increase in lactate and decrease in pyruvate levels (+42% and –43% mean change, respectively) in plasma separated from whole blood after 2 hours of collection compared to samples processed within 30 minutes. Plasma separated 1 hour postcollection was acceptable. Overnight fasting (12-14 hours) did not have a significant impact on ketones (3-hydroxybutyric and acetoacetic acids) or branched-chain ketoacids (2-keto-3-methylvaleric, 2-ketoisocaproic, 2-ketoisovaleric acids). In contrast, fasting samples displayed higher lactic acid concentrations compared to nonfasting samples (24% increase on average, P = .0072), although in most fasting samples (13 out of 14), lactate concentrations were still within established normal range (600-2,600 µmol/L). Conclusions We identified several preanalytical factors influencing plasma organic acid quantitation, particularly lactic and pyruvic acids. Since those are critical analytes, suggestive of primary or secondary metabolic acidosis, appropriate steps should be taken to ensure sample quality during collection and processing.

2020 ◽  
Vol 11 ◽  
Author(s):  
Fu-gui Jiang ◽  
Hai-jian Cheng ◽  
Dong Liu ◽  
Chen Wei ◽  
Wen-juan An ◽  
...  

We investigated the variation in microbial community and fermentation characteristics of whole-plant corn silage after treatment with lactic acid bacteria (LAB) and organic acids. The fresh corn forages were treated with a combination of L. acidophilus and L. plantarum (106 CFU/g fresh material) or a 7:1:2 ratio of formic acid, acetic acid, and propionic acid (6 mL/g fresh material) followed by 45 or 90 days of ensiling. Silages treated with LAB showed increased lactic acid content and decreased pH after 45 days. Although treatment with LAB or organic acids decreased the common and unique operational taxonomic units, indicating a reduction in microbial diversity, the relative abundance of Lactobacillus was elevated after 45 and 90 days compared with control, which was more distinct in the organic acid groups. Moreover, we found higher levels of acetic acid and increased abundance of Acetobacter in silages treated with organic acids whereas undesirable microorganisms such as Klebsiella, Paenibacillus, and Enterobacter were reduced. In summary, the quality of corn silages was improved by LAB or organic acid treatment in which LAB more effectively enhanced lactic acid content and reduced pH while organic acid inhibited the growth of undesirable microorganisms.


2019 ◽  
Vol 62 (1) ◽  
pp. 177-185
Author(s):  
Ewumbua M. Monono ◽  
Dennis P. Wiesenborn ◽  
Juan M. Vargas-Ramirez ◽  
Ruanbao Zhou

Abstract. Efficient and cost-effective methods are necessary to preserve the sugars in beet juice to enable year-long end-processing into bioproducts. Organic acids are effective preservatives that could be produced from a fraction of the sugars in beet juice to preserve the remaining sugar fraction. The preserving acids and remaining sugars may then serve as fermentation substrates in other bioprocesses. The effectiveness of organic acids to preserve sugars in beet juice has not been reported. Therefore, the objective of this work was to screen several potentially effective organic acids for their ability to accomplish sugar preservation in beet juice. Six organic acids (acetic, butyric, citric, lactic, propionic, and pyruvic) were used in three storage experiments in which beet juice was stored at four pH levels (5.3, 5, 4.25, and 3.5) and at 22.5°C for 21 to 38 days. Butyric, citric, and propionic acids helped preserve at least 92% of sugars at pH = 4.5, and lactic acid only at pH 3.5. Meanwhile, acetic and pyruvic acids helped preserve up to 88% of sugars at pH 3.5. Changes observed in the stored beet juice mainly occurred within the first 10 days, and thereafter the juice appeared stable. Before the storage experiments, the response of beet juice pH to different amounts of added acid was evaluated. There was an exponential decrease in pH as the molar ratio of acid increased. Future research should focus on developing methods to achieve the desired storage conditions and validating storage techniques through final fermentations of stored juice. Keywords: Acidification, Beta vulgaris, Fermentable sugars, Organic acid, pH, Refractometric dissolved solids, Sugarbeet.


2020 ◽  
Vol 8 (2) ◽  
pp. 172 ◽  
Author(s):  
Esmeray Kuley ◽  
Gulsun Özyurt ◽  
Ilyas Özogul ◽  
Mustafa Boga ◽  
Ismail Akyol ◽  
...  

Organic acid contents of acidified and fermented fish silages made from gibel carp (Caracius gibelio) and klunzinger’s ponyfish (Equulites klunzingeri) fishes, and from fish processing residues or by-products, were determined and studied. The silages were undertaken in wet and spray-dried fish-based raw-materials for 3 weeks at room temperature (ca. 25 °C). Selected lactic acid bacteria (LAB) of Enterococcus gallinarum, Lactobacillus brevis, Lactobacillus plantarum, Pediococcus acidilactici, and Streptococcus spp. were employed to produce fermented fish-based silages, while acidified silage was prepared resorting to the addition of formic acid (3%, v/v). Lactic and propionic acids were the dominant produced organic acids, while succinic acid was formed at the smallest amounts in fermented silages. In the acidified silage, lactic and formic acids were produced in amounts higher than 800 and 1000 mg organic acid/100 g sample, respectively. Among the fermented fish-based silages, LAB strains unfolded considerable ability to presumptively produce propionic acid in gibel carp silage (>2370 mg organic acid/100 g sample). Spray-dried fermented silages displayed significantly higher organic acid content than wet silages. Propionic acid accumulation was found at the highest levels in gibel carp silage fermented with L. plantarum (6335.40 mg propionic acid/100 g sample). This research effort pointed out the good capability of various selected lactic acid bacteria strains to produce significant amounts of organic acids—especially lactic, acetic, and propionic acids—during the fermentation of fish-based silages. In terms of food safety and quality, such a production of relatively high amounts of organic acids in wet and spray-dried fish-based silages clearly indicated their suitableness to be used for animal feed.


2017 ◽  
pp. 25-33 ◽  
Author(s):  
Elizabeth Quevedo ◽  
Erlinda Dizon ◽  
Florinia Merca

“Batuan” fruit (Garcinia binucao [Blco.] Choisy), an indigenous acidulant grown in the Visayas State University, Baybay City, Leyte was analyzed for its organic acid profile at different stages of maturity for the development of potential food and non-food products. The analysis of organic acid content was done using Reverse Phase-High Performance Liquid Chromatography. Organic acids in the dried, powdered “batuan” fruit samples were extracted with the mobile phase (50mM KH2PO4/ H3PO4, pH2.8). The sample extracts and organic acid standards (oxalic acid, tartaric acid, malic acid, citric acid, fumaric acid, lactic acid, acetic acid, and succinic acid) were injected to RP-HPLC under isocratic elution with the mobile phase at a flow rate of 1.0mL min-1 and using UV-vis detection at 210nm. “Batuan” fruit samples contain oxalic acid, tartaric acid, malic acid, citric acid, fumaric acid, succinic acid, acetic acid, lactic acid, and a few unidentified organic acids. Among the organic acids present, citric acid accumulated the highest in the ripe “batuan” fruit; fumaric acid, the least. Results of this study show that “batuan” fruit could be a good natural source of acidulant for food and non-food applications.


2021 ◽  
Vol 7 ◽  
Author(s):  
Hui Mei Chang ◽  
Hooi Ling Foo ◽  
Teck Chwen Loh ◽  
Eric Teik Chung Lim ◽  
Nur Elina Abdul Mutalib

Despite inflammation being a protective natural defense against imbalance stressors in the body, chronic inflammation could lead to the deterioration of immune response, low production, and poor performance in livestock as well as severe economic losses to the farmers. Postbiotics produced by Lactiplantibacillus plantarum has been reported recently to be a natural source of antioxidant, promoting growth performance, anti-inflammation, and immune responses. However, the effects of fermentation media on the compositions of L. plantarum postbiotic have not been reported elsewhere. Hence, a comparative study was conducted to compare the volatile compounds, organic acid composition, and antioxidant and antimicrobial activities of postbiotics produced by six strains of L. plantarum cultivated by using formulated media and the commercial de Man, Rogosa, and Sharpe (MRS) medium as a control. Postbiotics RG14, RI11, and UL4 produced by using formulated media exhibited higher inhibitory activity against Pediococcus acidilactici 446, Escherichia coli E-30, Salmonella enterica CS3, and vancomycin-resistant Enterococci except for Listeria monocytogenes LS55. As for the antioxidant activity, hydroxyl radical scavenging activity was enhanced in formulated media, whereas reducing power activity was the highest in postbiotic RI11. Three organic acids, namely, acetic acid, caproic acid, and lactic acid, were detected in the postbiotic produced by various L. plantarum strains. The concentration of acetic acid was influenced by the fermentation media, whereas caproic acid was detected as the highest in postbiotic RG11. Lactic acid was the predominant compound detected in all the postbiotics and had the significantly highest concentration in postbiotic RS5 when produced by using the MRS medium. Intermediary and pyrrole compounds were the other main compounds that were detected by using GC-MS. Positive correlations were found between organic acid production and inhibitory activity, as well as antioxidant activity exhibited by postbiotics. In conclusion, the compositions and functional characteristics of postbiotics produced by the six strains of L. plantarum were strain-dependent and affected greatly by the fermentation medium. The effects of postbiotic composition on the functional characteristics of postbiotics were elucidated in this study to warrant their applications as a promising beneficial natural growth promoter for the livestock industry.


1961 ◽  
Vol 16 (4) ◽  
pp. 709-712 ◽  
Author(s):  
D. Robert Axelrod

Voluntary hyperventilation in male human subjects produced a rise in plasma citric and lactic acid concentrations and a fall in inorganic phosphorus concentration. The maximum changes occurred 12—25 min after the end of 15—20 min of hyperventilation. Arterial-venous differences indicate that peripheral tissue was the source of the increased concentration of organic acids. The results suggest that hyperventilation produces a change in intermediary metabolism and that the formation of organic acid-calcium complexes decrease the calcium activity at the cell membrane. Submitted on December 21, 1960


2018 ◽  
Vol 773 ◽  
pp. 25-29
Author(s):  
Sung Yeon Hwang ◽  
Dong Yeop X. Oh ◽  
Je Young Park

In this study, high molecular weight (HMW) poly (l-lactic acid)s (PLLAs) were synthesized by direct polycondensation using organic acid catalysts alone in a nitrogen-controlled environment. The melting point and enthalpy of the pre-polymer produced by melt polycondensation increased as molecular weight grew during solid-state polycondensation. It was observed that the nitrogen-controlled external environment had lower molecular weight than air, but the low molecular weight tail was significantly reduced, as indicated by gel permeation chromatography. This is because it inhibited the reverse reaction by preventing the penetration of water inside the reactor. Also, the control of moisture improved the color of PLLA. The amount of organic acid catalyst used was 1 wt%, which was favorable for achieving HMW. Both p-toluenesulfonic acid and 4-ethylbenzenesulfonic acid are examples of organic acids that were able to produce HMW PLLA.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3341
Author(s):  
Alessandra Frau ◽  
Lauren Lett ◽  
Rachael Slater ◽  
Gregory R. Young ◽  
Christopher J. Stewart ◽  
...  

The fecal metabolome in early life has seldom been studied. We investigated its evolution in pre-term babies during their first weeks of life. Multiple (n = 152) stool samples were studied from 51 babies, all <32 weeks gestation. Volatile organic compounds (VOCs) were analyzed by headspace solid phase microextraction gas chromatography mass spectrometry. Data were interpreted using Automated Mass Spectral Deconvolution System (AMDIS) with the National Institute of Standards and Technology (NIST) reference library. Statistical analysis was based on linear mixed modelling, the number of VOCs increased over time; a rise was mainly observed between day 5 and day 10. The shift at day 5 was associated with products of branched-chain fatty acids. Prior to this, the metabolome was dominated by aldehydes and acetic acid. Caesarean delivery showed a modest association with molecules of fungal origin. This study shows how the metabolome changes in early life in pre-term babies. The shift in the metabolome 5 days after delivery coincides with the establishment of enteral feeding and the transition from meconium to feces. Great diversity of metabolites was associated with being fed greater volumes of milk.


2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 209-210
Author(s):  
Casey L Bradley ◽  
Jon Bergstrom ◽  
Jeremiah Nemechek ◽  
J D Hahn

Abstract A subset of 720 weaned pigs (6.44 ± 0.1 kg, PIC genetics, approximately 21-d of age) were used in a 42-d trial with a 2x3 factorial design evaluating the effects of adding organic acid (OA) blends [factor 1 = no organic acid (NO), Acid Pak 1 (AP1), Acid Pak 2 (AP2)] to diets with or without higher levels of Zn or Cu [factor 2 = +/-PZC] on pig performance. Pigs were allotted 10 pigs/pen to 12 weight blocks and randomly assigned the six dietary treatments. The +PZC diets contained 3000 ppm Zn (d 0-7), 2000 ppm Zn (d 8-21), and 250 ppm Cu (d 21-42) and -PZC diets contained 95 ppm Zn and 20 ppm Cu (d 0-42). The AP1 and AP2 diets used 0.9% of 2 acid premixes (d 0-21), and 0.45% of the premixes (day 22-42). AP1 provided 0.5% benzoic acid, 0.07% sodium butyrate, and 0.025% phosphoric acid (day 0-21) and half those levels (day 22-42). AP2 included the same acids as AP1 but at half the rate and combined with 7 other organic acids and carvacrol. From d 0-21, ADG, ADFI, and G:F were improved (P&lt; 0.01) by +PZC compared to -PZC and by AP1 or AP2 compared to NO (P&lt; 0.02). Overall (d 0-42), ADG and G:F were improved (P&lt; 0.01) by +PZC compared to -PZC and by AP1 or AP2 compared to NO (P&lt; .010). Data from this trial indicate that performance was improved by the addition of both OA and PZC. However, pigs fed OA and -PZC performed similarly to those fed NO and +PZC in the post-weaning period. In summary, regardless of the acid combination, organic acid supplementation has the potential to improve growth performance in weaned pigs.


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