HPLC analysis of phenylthiocarbamyl (PTC) amino acids. I. Evaluation and optimization of the procedure

Janssen, P. S. L.; Nispen, J. W. van; Melgers, P. A. T. A.; Bogaart, H. W. M. van den; Hamelinck, R. L. A. E.; Goverde, B. C.

doi:10.1007/bf02268788

Cited by 39 publications

(20 citation statements)

References 14 publications

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“…The derivatization procedure is similar to that one adopted by Janssen et al [21]. One hundred microliters or 25 µL of the final extracts, obtained for the total and the free amino acids respectively, were added with 25 µL of 10 -3 M Norleucine (Nle) used as an internal standard (I.S.)…”

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confidence: 99%

Chemical composition and nutritional evaluation of some natural and commercial food products based on Spirulina

1999

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Blue-green algae have been attracting the most attention as potential, indeed actual, sources of proteins and other human and natural nutrients (fatty acids, macro-and trace minerals). Among these algae, the filamentous cyanobacterium Spirulina appears to be a ubiquitous component of the phytoplankton growing in ocean and seawaters (from tropical lagoons to Arctic waters, thermal springs, alcaline lakes etc.) [1][2][3]. This alga is protein rich (up to 70% protein by dry weight), contains essential amino acids [4], is easily digestible and is much larger than unicellular alga which simplifies harvesting [5]. The low content of cholesterol and lipids [6,7] and the presence of minerals, vitamins, carbohydrates, essential fatty acids, sterols [1] and blue pigments, the phycocianins, which contribute to increase the protein and iron availability [8] have been also proven.Further, the presence of an anti-oxidizing agent as β-carotene and the rare γ-linolenic acids [9,10] However, Spirulina commercialized in the form of pills or tablets is recommended by suppliers mainly as a health food, a protein source, vitamin supplement, diet pill and as a treatment for anemia in humans. The commercialization of the alga biomass (processing, packaging and distribution) may introduce environmental pollution or variation of the chemical composition of the product. Cultivation techniques, developed to raise productivity levels so that the increasing demand for these products can be satisfied, may also change the chemical composition [17,3] and consequently the nutritional and toxicological properties of the final products. Furthermore, while chemical composition of algae has been the subject of increasing attention, seldom, have extensive chemical analysis of commercial products been performed.In this paper, the chemical composition of Spirulina platensis products of both a natural and a commercial Cuban origin and of four commercial (non-Cuban) products available on the Italian market, is reported. The level of macrominerals, trace elements, phycobiliproteins, free and total amino acids, fatty acids has been determined while a method is proposed for the extraction, recovery and determination of phycobiliproteins. The data are also compared with other commercial products based on Spirulina and some parameters are evaluated with reference to Food and Agriculture Organization (FAO) values. 533Chemical composition and nutritional evaluation of some natural and commercial food products based on Spirulina L. Campanella * , G. Crescentini † and P. AvinoDepartment of Chemistry, University of Rome "La Sapienza", Piazzale Aldo Moro 5, 00185, Rome, Italy Abstract. A natural and a commercial Spirulina product of Cuban origin have been extensively studied together with four algal food products available on the Italian market. The contents of macrominerals, trace elements, free and total amino acids, fatty acids and of two important phycobiliproteins (C-phycocyanine and allophycocyanine) have been determined. The results are compared with th...

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confidence: 99%

Chemical composition and nutritional evaluation of some natural and commercial food products based on Spirulina

1999

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“…The nitrogen uptake from ammonium phosphate was defined as the difference between the initial and final amount following fermentation. The concentration of amino acids in the fermented must was determined by HPLC, according to the method described by Janssen et al (11). The samples from natural must were previously hydrolyzed with HCl 6 N and 1 % phenol for 1 h at 150 °C.…”

Section: Methodsmentioning

confidence: 99%

Development and characterization of hybrids from native wine yeasts

García¹,

Rivera²,

Contreras³

et al. 2012

Braz. J. Microbiol.

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For commercial purposes, the winemaking industry is constantly searching for new yeast strains. Historically, this has been achieved by collecting wild strains and selecting the best for industrial use through an enological evaluation. Furthermore, the increasing consumer demands have forced the industry to incorporate new strategies such as genetic engineering to obtain improved strains. In response to the lack of public acceptance of this methodology, alternative strategies based on breeding have gained acceptance in recent years. Through the use of conjugation of individual spores without the support of genetic engineering methods we generated intraspecific hybrids from wild strains with outstanding enological characteristics and interdelta fingerprinting was used to confirm the hybrid condition. A detailed enological characterization of the hybrids in synthetic and natural must indicates that physiological parameters such as sporulation, residual sugar, ethanol yield and total nitrogen uptake are within the levels determined for the parental strains, however, other parameters such as growth rate, lag phase and ethanol production show statistical differences with some parental or commercial strains. These findings allow us to propose these hybrids as new wine-making strains.

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“…But this stability is only relative. Many researchers have considered the stability of dried PTH-amino acids in refrigeration and freezing conditions, reporting different lifetimes from one to several months kept freeze -dried [23,27,43] [45]. In view of this, we decided to perform a stability study of the reconstituted derivatives in buffer solution at room temperature.…”

Section: Pth-amino Acid Derivative Stability In Solutionmentioning

confidence: 99%

“…The PITC derivatization method has been widely applied and different modifications have been proposed; nevertheless, the proposed modifications mainly concerned previous steps in the method such as hydrolysis or amino acid derivatization [26,27], but few [28,29] concern scale reduction with an increase in analytical performance. In this work, we revisited this well known chromatographic method in order to implement it in a microbore column more appropriate to our objectives.…”

Section: Introductionmentioning

confidence: 99%

Revisitation of the phenylisothiocyanate‐derivatives procedure for amino acid determination by HPLC‐UV

Checa-Moreno

Manzano

Mirón

et al. 2008

J of Separation Science

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A revisitation of the well known chromatographic procedure for the determination of amino acids as phenylthiocarbamyl derivatives (PTC) is performed. The method was developed for a microbore column that it is more appropriate to our later aims, the characterization of proteinaceous binders present in microsamples coming from the Cultural Heritage field. Several variables relating to chromatographic aspects were studied such as the pH and temperature of the mobile phase, buffer and modifier (triethylamine) concentrations in mobile phase and the stability of PTC-derivatives in solution. The calibration function was studied in depth. To prevent the heteroscedastic behaviour that it is observed, we used the weighed least squares fitting as the best strategy among other normalizing transformations, such as square root and logarithmic functions. Finally, the proposed method showed results similar to the traditional method in terms of efficiency, runtime, LODs and other characteristics, but with two additional advantages: a lower mobile phase consumption and the possibility of working with a lower sample volume. The usefulness of proposed method is checked against easel painting samples of Pictorial Heritage.

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HPLC analysis of phenylthiocarbamyl (PTC) amino acids. I. Evaluation and optimization of the procedure

Cited by 39 publications

References 14 publications

Chemical composition and nutritional evaluation of some natural and commercial food products based on Spirulina

Chemical composition and nutritional evaluation of some natural and commercial food products based on Spirulina

Development and characterization of hybrids from native wine yeasts

Revisitation of the phenylisothiocyanate‐derivatives procedure for amino acid determination by HPLC‐UV

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