Abstract
Many of the extraction and amino acid analysis methodologies currently employed do not provide complete analysis of all the physiological amino acids and biogenic amines. Extraction procedures frequently employ dilute acid which partially converts gln and asn to glu and asp. A commonly used pre-column derivatizing agent, o-phthalaldehyde, does not react with the imino acids, pro and hydroxypro. The purpose of this investigation was to integrate extraction and analysis procedures into a reliable method for measuring the complete physiological amino acid profiles of fruit and vegetables using HPLC instrumentation commonly available to most laboratories. Water extraction of ground, frozen-thawed tissues effected complete recovery of the physiological amino acids as demonstrated by spiking experiments and tissue combination experiments. HPLC of dabsyl derivatives of the free amino acids allowed their quantification in a selection of fruit and vegetables. Physiological amino acid levels were determined for peach, apple, potato, onion, tomato, bell pepper, broccoli, and seven types of cucurbits. The coefficient of variation for estimation of an amino acid level generally fell in the range of 5% to 7%. Because of marked variability in physiological amino acid content as a result of growing conditions, cultural practices, and inherent cultivar differences, comparisons of results with literature values were not possible.
Highlights
Our interest in the physiological levels of amino acids in fruits and vegetables as a function of growing conditions and stage of fruit development led us to explore various extraction and analysis methodologies that effected quantitative extraction without modification and that did not require expensive, dedicated instrumentation for analyses
HPLC of dabsyl derivatives of the free amino acids allowed their quantification in a selection of fruit and vegetables
Physiological amino acid levels were determined for peach, apple, potato, onion, tomato, bell pepper, broccoli, and seven types of cucurbits
Summary
Our interest in the physiological levels of amino acids in fruits and vegetables as a function of growing conditions and stage of fruit development led us to explore various extraction and analysis methodologies that effected quantitative extraction without modification and that did not require expensive, dedicated instrumentation for analyses. With the advent of volatile derivatives of amino acids for GC [3], HPLC with pre- and postcolumn amino acid derivatization [4,5,6,7], and more recently, GC and HPLC with mass spectral monitoring [3, 8], ion exchange-based amino acid analysis no longer commands the prominence that it once did These more contemporary methods afford a wider availability of methodology for protein hydrolysate amino acid analysis, resolution of some physiological amino acids and biogenic amines is frequently not on par with the older ion exchange systems. A number of the amino acid analysis methodologies are hampered by FNS
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
