Rapid Determination of Total Tryptophan in Yoghurt by Ultra High Performance Liquid Chromatography with Fluorescence Detection

Ritota, Mena; Manzi, Pamela

doi:10.3390/molecules25215025

Cited by 13 publications

(5 citation statements)

References 46 publications

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“…Having this in mind, the importance of determining this amino acid in biological samples, as well as in food samples can be accomplished. Although a number of classical methods 5 – 7 are available to quantify this target analyte, electrochemical techniques have become important in this research field. Voltammetry is an electrochemical and electroanalytical technique based on measuring current as a function of applied potential.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical determination of L-tryptophan in food samples on graphite electrode prepared from waste batteries

Tasić

Mihajlović

Radovanović

et al. 2022

Sci Rep

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One of the goals of this research was to develop an electrochemical sensor that had the ability to determine the target analyte and was both cheap and non-toxic. Another goal was to influence the reduction of electronic waste. In accordance with these, a graphite rod from zinc-carbon batteries was used to prepare an electrochemical sensor for the determination of L-tryptophan in Britton–Robinson buffer solution. Two electrochemical methods were used in the experimental research, differential pulse voltammetry and cyclic voltammetry. The effect of different parameters, including the pH value of supporting solution, scan rate, as well as the concentration of L-tryptophan on the current response, was studied. The pH value of Britton–Robinson buffer influenced the intensity of L-tryptophan oxidation peak, as well as the peak potential. The intensity of the current response was the highest at pH 4.0, while the peak potential value became lower as the pH increased, indicating that protons also participated in the redox reaction. Based on the obtained data, electrochemical oxidation of L-tryptophan at the graphite electrode was irreversible, two electron/two proton reaction. In addition, it was observed that the oxidation peak increased as the scan rate increased. According to the obtained electrochemical data, it was suggested that the oxidation of L-tryptophan was mixed controlled by adsorption and diffusion. The linear correlation between oxidation peak and L-tryptophan concentration was investigated in the range 5.0–150.0 µM and the obtained values of limit of detection and limit of quantification were 1.73 µM and 5.78 µM, respectively. Also, the prepared electrochemical sensor was successful in determination of target analyte in milk and apple juice samples.

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Section: Introductionmentioning

confidence: 99%

Electrochemical determination of L-tryptophan in food samples on graphite electrode prepared from waste batteries

Tasić

Mihajlović

Radovanović

et al. 2022

Sci Rep

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“…In terms of limiting essential AAs, the small amounts of threonine, phenylalanine, isoleucine and methionine in the prolamins, and of methionine, lysine and isoleucine in the other fractions, are in general agreement with previous reports [ 31 , 32 , 33 ]. Tryptophan was not reported in most studies nor in our work because it is easily destroyed during AA analysis [ 34 ]. The AA content of the globulin fraction could not be determined due to the low protein content of this fraction.…”

Section: Resultsmentioning

confidence: 99%

Functional and Bioactive Properties of Wheat Protein Fractions: Impact of Digestive Enzymes on Antioxidant, α-Amylase, and Angiotensin-Converting Enzyme Inhibition Potential

et al. 2023

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This research aimed to determine the biofunctional properties of wheat flour (WF) protein fractions and modifications to the antioxidant, anti-α-amylase and anti-angiotensin-I converting enzyme (ACE) activities induced by the action of digestive endopeptidases in vitro. A molecular characterization of the most abundant protein fractions, i.e., albumins, glutelins-1, glutelins-2 and prolamins, showed that low- and high-MW polypeptides rich in cysteine, glutamic acid and leucine were present in albumins and glutelins, whereas low-MW subunits with a high proportion of polar amino acids prevailed in prolamins. Prolamins exhibited the second-highest water holding capacity (54%) after WF (84%), while albumins provided superior foam stability (76%). Prolamins, glutenins-1 and globulins demonstrated the highest antioxidant activity (up to 95%, 68% and 59%, respectively) both before and after hydrolysis with pepsin (P-H) or trypsin–chymotrypsin (TC-H). Prolamins, globulins and WF strongly inhibited α-amylase (>90%) before and after TC-H, and before P-H (55–71%). Moreover, P-H significantly increased α-amylase inhibition by albumins from 53 to 74%. The fractions with strong ACE inhibitory activity (70–89%) included prolamins and globulins after TC-H or P-H, as well as globulins before TC-H and WF before P-H. This novel evidence indicates that WF protein fractions and their peptide-enriched P and TC hydrolysates are excellent sources of multifunctional bioactives with antioxidant, antihyperglycemic and antihypertensive potential.

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“…Neither the addition of salt nor the drying method significantly affected the content of the majority of essential amino acids (EAA) (threonine, valine, methionine, phenylalanine, histidine, and lysine) and non‐EAA (serine, glycine, alanine, cystine, and proline). Tryptophane was not reported as it is generally destroyed during the acid hydrolysis step of AA analysis (Ritota & Manzi, 2020). However, the concentration of two EAA (isoleucine and leucine) was significantly higher in SdSa jameed compared with FdUs jameed.…”

Section: Resultsmentioning

confidence: 99%

Characterization and biological properties of peptides isolated from dried fermented cow milk products by RP‐HPLC: Amino acid composition, antioxidant, antihypertensive, and antidiabetic properties

Alu’datt

Al-U’datt

Alhamad

et al. 2021

Journal of Food Science

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This study aimed to assess the biological properties of peptide fractions isolated from dried fermented dairy products (jameed) as influenced by processing. Peptide fractions were separated by reversed‐phase high‐performance liquid chromatography (RP‐HPLC) from salted (Sa) and unsalted (Us) cow milk jameed after drying the fermented curd by sun drying (Sd) or freeze‐drying (Fd) and were characterized for their antioxidant capacity and inhibitory activity toward angiotensin I‐converting enzyme (ACE) and α‐amylase. Sd samples showed more numerous peptide peaks in RP‐HPLC chromatograms than Fd samples, regardless of the salt content. High antioxidant activity was evidenced in several peptide fractions from FdUs jameed (including fractions 1, 2, 4, 7, 8, 9, and 10), SdUs jameed (1, 2, 5, 7, and 9), and FdSa jameed (2, 5, 6, and 9). By contrast, peptide fractions from SdSa (1, 2, 3, 5, 8, and 9), SdUs (4, 5, and 10), and FdUs (5, 6, and 8) jameed displayed the highest ACE inhibitory activity. Similarly, the highest inhibition of α‐amylase was obtained with fractions from SdSa (1, 2, 3, 4, 5, 6, 8, and 9), SdUs (2 and 6), and FdUs (1, 7 and 9) jameed. A significant negative correlation was evidenced between antioxidant activity and anti‐α‐amylase activity of peptide fractions from SdSa jameed. These findings demonstrate that cow milk jameed is a source of bioactive peptides with antioxidant, anti‐ACE, and anti‐α‐amylase properties in vitro, which can be tailored by adjusting the salt content and the drying conditions. Practical Application This study shows that cow milk jameed, a staple fermented food in several Mediterranean countries, can serve as a useful source of multifunctional bioactive peptides with potential antioxidant, hypotensive, and hypoglycemic effects, which may help prevent and manage chronic health conditions such as hypertension, type 2 diabetes, and the metabolic syndrome. The bioactivities of certain peptide fractions were enhanced by lowering the salt content of jameed or by the drying method. The relatively simple RP‐HPLC method described in this study can be used to isolate the peptide fractions of interest for further characterization and use as functional ingredients.

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Rapid Determination of Total Tryptophan in Yoghurt by Ultra High Performance Liquid Chromatography with Fluorescence Detection

Cited by 13 publications

References 46 publications

Electrochemical determination of L-tryptophan in food samples on graphite electrode prepared from waste batteries

Electrochemical determination of L-tryptophan in food samples on graphite electrode prepared from waste batteries

Functional and Bioactive Properties of Wheat Protein Fractions: Impact of Digestive Enzymes on Antioxidant, α-Amylase, and Angiotensin-Converting Enzyme Inhibition Potential

Characterization and biological properties of peptides isolated from dried fermented cow milk products by RP‐HPLC: Amino acid composition, antioxidant, antihypertensive, and antidiabetic properties

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