A sensitive HPLC-FLD method combined with multivariate analysis for the determination of amino acids in l-citrulline rich vegetables

Abstract

The proposed analytical method reports the separation and quantification of 21 amino acids including l -citrulline from fresh vegetables and commercial juices using a C 8 column. Optimal separation conditions for amino acids analysis were obtained with 20 mM sodium acetate (solvent A) and water with organic modifier acetonitrile and methanol (solvent B; 18/50/32 V/V). The ideal pH and column temperature were found to be 5.40 and 35 °C, respectively. The LOD and LOQ values were obtained in the range of 0.02–0.19 ng/mL and 0.04–0.39 ng/mL for all amino acids respectively. Relative standard deviations (RSD) of intraday and interday analysis were found to be <2.7% and 7.9%, respectively. The recovery of amino acids were found be satisfactory for all the tested crops. The developed method was successfully used for the quantification of amino acids in six fresh vegetable juices including watermelon, cucumber, celery, calabaza squash, zucchini squash, yellow squash and commercial juices. Multivariate analysis was used to determine the significant differences in the amino acids profiles. l -citrulline content was highest in fresh watermelon juice (716.57 ± 24.80 μg/mL) and commercial watermelon lime juice (826.48 ± 34.48 μg/mL). The optimized analytical method is rapid, sensitive, accurate and reproducible for analysis of free amino acids including l -citrulline from different vegetable juices and other food products. To the best of our knowledge, this is the first report to separate OPA derivatives of amino acids using C 8 column from watermelon, cucumber, zucchini squash, yellow squash, calabaza squash, and celery in a HPLC-FLD system.

Multivariate Analysis of Amino Acids and Health Beneficial Properties of Cantaloupe Varieties Grown in Six Locations in the United States

“…Melon varieties CRU (IN) and ALG (AZ) had significantly higher levels of Cit at 360.52 ± 23.49 and 307.33 ± 58.84 µg/g, respectively, than the other varieties harvested from different locations. Citrulline, a non-essential amino acid and precursor to the arginine, is mainly present in Cucurbitaceae family members such as watermelon, squash, and cucumber [ 5 ]. A recent study reported the effect of two growing locations in NC on Cit and Arg levels, using different cultivars from those we studied here.…”

“…Melon fruits have high levels of the GABA [ 3 ] and other amino acids, particularly valine and alanine [ 4 ]. Amino acid identification and quantification of melon can be performed by reverse phase liquid chromatography, gas chromatography, and nuclear magnetic resonance [ 5 , 6 , 7 ]. Liquid chromatography is a commonly used technique for analysis of amino acids from plants.…”

“…Analysis is mainly performed by liquid chromatography coupled with ultraviolet, diode-array, fluorescent, or mass detectors after derivatization. Commonly used derivatization reagents are dansyl-chloride, O -phthalaldehyde, 9-fluorenylmethyloxycarbonyl, and 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate [ 5 , 8 , 9 , 10 ].…”

Recent Techniques in Nutrient Analysis for Food Composition Database

“…Among the most common labelling reagents used for post- and pre-column derivatization are ninhydrin and o-phthaldialdehyde (OPA), 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC), phenylisothiocyanate (PITC) and 9-fluorenylmethyl chloroformate (FMOC) respectively [ 160 ]. However, there was a report of using OPA as pre-column derivatization to enhance sensitivity for fluorescent detection [ 137 ]. Derivatization process was made easier and simpler when using AQC as it is stable at room temperature for several days, has low toxicity, fewer side reactions and takes a shorter time to complete [ 143 ].…”

Study of Quality of Snack Gherkin Tinned Food

“…Suppression of different microorganisms is manifested even at small concentrations of acetic acid (0.2-0.3 % of acid of the total mass of pickled products). At small concentration 0.4-0.6 % of acetic acid subacid marinades, not stable at storage, form [1][2][3][4][5]. As a result of the small concentration of vinegar, microorganisms in such marinades are partially suppressed, their essential part can develop and cause spoilage of the product.…”