Quantitative Evaluation of the Pyruvic Acid Content in Onion Samples with a Fully Validated High-Performance Liquid Chromatography Method

Abstract

Onion cultivars with low pungency have been increasing in popularity because they are more attractive for fresh, uncooked use. The pyruvic acid amount is commonly used as a measure of onion pungency. For the first time the validation of a reversed-phase high-performance liquid chromatography method for the quantitative analysis of pyruvic acid in onion extracts was carried out. The established chromatography method based on the use of a 50 mM phosphate buffer (pH 2.5) eluent system provided good precision (RSD% in the range of 1.25-1.29, in the long-period) and accuracy (recov-ery% in the range of 97.70-111.62, in the long-period) as well as appreciably low limit of detection and limit of quantitation values (11.03 and 33.41 ng/mL, respectively). The validated method proved successful in the analysis of the onion extract from Dorata di Parma cultivar after a preliminary solid-phase extraction step. A significant adherence with results from previous spectrophotometric determinations turned out.

Antioxidants and Bioactive Compounds in Licorice Root Extract Potentially Contribute to Improving Growth, Bulb Quality and Yield of Onion (Allium cepa)

“…Pungency level is an important quality attribute in onion bulb. Although onion pungency is preferable in many applications (e.g., sauce), low-pungent onion cultivars are highly preferable in households, as well as in extensive use in retail, food service, and numerous food industries, owing to their minimal lachrymatory properties and ease of use as a fresh and uncooked ingredient [ 44 , 45 ]. Pyruvic acid, a product accompanied by the formation of different thiosulfinates through alliinase, is widely recognized as a measure of the pungency index in onions [ 46 ].…”

Hydrophobic Amino Acid Content in Onions as Potential Fingerprints of Geographical Origin: The Case of Rossa da Inverno sel. Rojo Duro

“…We have long been interested in the study and definition of the properties of onions from Cannara, a small town in the Umbria region (Italy) [ 4 , 5 , 6 ]. In particular, in the frame of a broader project, we were interested, inter alia, at comparing the amino acid content in a specific variety of onion ( Rossa da inverno sel.…”

"High Throughput Chemical Quantification of Pyruvate in Sweat in Response to Modulation by Nutritional Supplementation and Exercise"

“…As such, various enzymatic, analytical, and chemical methods have been used to quantify the abundance and distribution of pyruvate [6,16]. High performance liquid chromatography (HPLC) and capillary electrophoresis (CE), represent gold standard techniques for the separation, detection, and quantification of this molecule [5,17,18].…”

“…Informed consent was obtained from each athlete following Regulatory Ethics Board approval which included the consumption of a Health Canada approved on-market nutritional supplement (NPN80070757) containing a pyruvate as described by Badulescu, et al [15]. Sweat pyruvate concentrations were determined chemically according to Sharma, et al [4], which is a modification of the method proposed by MacLean [17]. This chemical approach was further modified to accommodate a sweat sample matrix obtained from athletes following a prescribed exercise protocol as described in Figure 1.…”