Development of NIRS Equations for Food Grain Quality Traits through Exploitation of a Core Collection of Cultivated Sorghum

Abstract

A sorghum core collection representing a wide range of genetic diversity and used in the framework of a sorghum breeding and genetics program was evaluated by near-infrared reflectance spectroscopy (NIRS) to predict food grain quality traits: amylose content (AM), protein content (PR), lipid content (LI), endosperm texture (ET), and hardness (HD). A total of 278 sorghum samples were scanned as whole and ground grain to develop calibration equations. Laboratory analyses were performed on NIRS sample subsets that preserved the core collection racial distribution. Principal component analysis performed on NIRS spectra evidenced a level of structure following known sorghum races, which underlined the importance of using a wide range of genetic diversity. Performances of calibration equations were evaluated by the coefficient of determination, bias, standard error of laboratory (SEL), and ratio of performance deviation (RPD). Ground grain spectra gave better calibration equations than whole grain. PR equation (RPD of 5.7) can be used for quality control. ET, LI, and HD equations (RPD of 2.9, 2.6, and 2.6, respectively) can be used for screening steps. Even with a small SEL in whole sample analysis, a RPD of 1.8 for AM confirmed that this variable is not easy to predict with NIRS.

Grain Sorghum: A Conundrum for Chicken-Meat Production

“…Our group has determined the Symes PSI texture [37] of 38 sorghum varieties; the mean PSI value was 9.84 ± 1.603 which is in the more rigid end of the "very hard" scale and only two varieties or 5.3% of samples were "softer" in this scale. These findings are in contrast to an extensive global survey recorded by de Alencar Figueiredo, et al [38]. In this survey the mean PSI texture of 117 sorghum samples was 12.7 but 44% of samples had softer textures than "very hard" as opposed to 5.3% in the local sorghum varieties.…”

“…The mean PSI value was 9.84 ± 1.603 (co-efficient of variation: 16.3%) which is at the harder end of the "very hard" spectrum of 8 to 12 inclusive and only three varieties fell outside this category. On the basis of this method Australian sorghums are noticeably "harder" with lower PSI values than those from an extensive global survey recorded by de Alencar Figueiredo, et al [38]. In this survey the mean texture of 117 sorghum samples was in the order of 12.7% but 44% of samples had softer textures than "very hard" as opposed to 5.3% (2 ex 38) in Australian sorghums.…”

Application of near-infrared reflectance spectroscopy for the estimation of protein and L-canavanine contents in seeds of one-flowered vetch (Vicia articulata Hornem.)

“…The best equation for the estimation of total protein by NIRS was obtained without the visible part of the spectral information. Some authors have also discarded the visible region for the estimation of protein contents in seeds of sorghum or rapeseed claiming an increase of noise of the models when it is included (Velasco and Möllers, 2002;De Alencar Figueiredo et al, 2006). For the estimation of L-canavanine the best equation was obtained by selecting to calibrate the regions where the standard L-canavanine displayed the main bands of absorption, which included both visible and infrared regions (Figure 1).…”

A Review of Optical Nondestructive Visual and Near-Infrared Methods for Food Quality and Safety

“…Figueiredo et al [253] studied a wide range of sorghum cores with high genetic diversity. They used NIR reflectance to determine amylase, protein, and lipid contents, endosperm texture, and hardness.…”