Background: As a powerful antioxidant and natural colorant, anthocyanins are being used increasingly as a component of food supplements and nutraceutical products. Hence, its characterization is a prerequisite for further exploration of its nutraceutical potential. UV-Vis and MS are the two important techniques, which have been largely employed for the qualitative and quantitative determination of anthocyanins. However, a comprehensive review of the applications of these techniques in literature is scarce. Objective: This paper aims to review the utilization of UV-Vis spectral data as well as mass spectral data for characterization and putative identification of anthocyanins with approaches of quantification. Methods: The techniques described in literature have been thoroughly reviewed and comparatively evaluated. The complementary approaches of UV-Vis and MS spectra have been discussed for identification and quantification of these compounds. Results: Valuable information about the chemical composition and structure of anthocyanins can be predicted from the UV-Vis spectral data, such as number and type of glycosylation as well as absence or presence of acylation, to name a few. It is also pointed out that for their structural confirmation, selectivity of mass detectors with unit and high-resolution analysis could be effective. Conclusions: The combination of LC-MS with UV-Vis spectroscopy provides complementary information on structural details of anthocyanins. In case the analytical reference standards are available, a triple quadrupole mass spectrometer provides selectivity and quantitative sensitivity in analysis. On the other hand, high-resolution MS analysis provides valuable information for tentative identification during nontarget screening of compounds when the reference standard is not available. Highlights: This paper reviews the applications of UV-Vis spectroscopy and LC-MS for qualitative and quantitative analysis of anthocyanins.

Onion is among the most widely cultivated and consumed economic crops. Onions are an excellent dietary source of polyphenols and nutrients. However, onions phytonutrient compositions vary with cultivars and growing locations. Therefore, the present study involved the evaluation of polyphenol, nutritional composition (proteins, nitrogen, and minerals), sugars, pyruvate, antioxidant, and α-amylase inhibition activities of red onion cultivars, sweet Italian, and honeysuckle grown in California and Texas, respectively. The total flavonoid for honeysuckle and sweet Italian was 449 and 345 μg/g FW, respectively. The total anthocyanin for honeysuckle onion was 103 μg/g FW, while for sweet Italian onion was 86 μg/g FW. Cyanidin-3-(6”-malonoylglucoside) and cyanidin-3-(6”-malonoyl-laminaribioside) were the major components in both the cultivars. The pungency of red onions in honeysuckle ranged between 4.9 and 7.9 μmoL/mL, whereas in sweet Italian onion ranged from 8.3 to 10 μmoL/mL. The principal component analysis was applied to determine the most important variables that separate the cultivars of red onion. Overall results indicated that total flavonoids, total phenolic content, total anthocyanins, protein, and calories for honeysuckle onions were higher than the sweet Italian onions. These results could provide information about high quality and adding value to functional food due to the phytochemicals and nutritional composition of red onions.

The Arabidopsis CCA1 influences plant resistance to green peach aphids by modulating indole glucosinolate biosynthesis.

The proposed analytical method reports the separation and quantification of 21 amino acids including l-citrulline from fresh vegetables and commercial juices using a C8 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 C8 column from watermelon, cucumber, zucchini squash, yellow squash, calabaza squash, and celery in a HPLC-FLD system.