Assaying Total Carotenoids in Flours of Corn and Sweetpotato by Laser Photoacoustic Spectroscopy

Abstract

This study describes the application of the laser photoacoustic spectroscopy (PAS) for quantification of total carotenoids (TC) in corn flours and sweetpotato flours. Overall, thirty-three different corn flours and nine sweetpotato flours were investigated. All PAS measurements were performed at room temperature using 488-nm argon laser radiation for excitation and mechanical modulation of 9 and 30 Hz. The measurements were repeated within a run and within several days or months. The UV–Vis spectrophotometry was used as the reference method. The concentration range that allows for the reliable analysis of TC spans a region from 1 to 40 mg kg−1 for corn flours and from 9 to 40 mg kg−1 for sweetpotato flours. In the case of sweetpotato flours, the quantification may extend even to 240 mg kg−1 TC. The estimated detection limit values for TC in corn and sweetpotato flours were 0.1 and 0.3 mg kg−1, respectively. The computed repeatability (n = 3–12) and intermediate precision (n = 6–28) RSD values at 9 and 30 Hz are comparable: 0.1–17.1% and 5.3–14.7% for corn flours as compared with 1.4–9.1% and 4.2–23.0% for sweetpotato flours. Our results show that PAS can be successfully used as a new analytical tool to simply and rapidly screen the flours for their nutritional potential based on the total carotenoid concentration.

Total Content of Carotenoids in Corn Landraces and Their Potential Health Applications

“…Phenotypic selection based on the colour of corn cob may provide various advantages in economy but also in breeding programs, aimed at increasing the amount of carotenoids in corn, since the chemical analysis performed to measure these compounds are expensive and time consuming. In recent decades the number of studies has greatly increased (Rafael da Silva Messias et al, 2014; Kristina Kljak et al, 2012; Svjetlana Luterotti and Kristina Kljak, 2010;Berardo et al, 2009) relating to phytochemical elements so the connection between nutrition and health has always been founded on scientific researches.…”

On the photoacoustic, photothermal and colorimetric quantification of carotenoids and other phytonutrients in some foods: a review

“…In a recent study the PA detector (operated at 9 and 30 Hz) in combination with an argon-ion laser emitting 75 mW at 488 nm was used to assess the total carotenoid (TC) content of 33 corn flours and nine sweet potato flours [29]. Both kinds of flour contain a diversity of carotenoids among which beta-carotene dominates.…”

Optical absorption spectra of germinated seedlings from seeds exposed to vehicle polluting gases

“…PAS has been used to evaluate a wide variety of seeds, grains and seedlings providing valuable information on their physical properties [27][28][29][30]. Also PAS technique allows a nondestructive analysis from the optical absorption spectra of different samples, including optically opaque samples [31,32].…”