Diferenciação de cultivares de girassol por espectroscopia no infravermelho próximo e análise multivariada, utilizando sementes e óleo

Abstract

RESUMO: Neste trabalho se objetivou avaliar a técnica de espectroscopia no infravermelho próximo (NIR) e a análise multivariada para a diferenciação de cultivares de girassol utilizando sementes e óleo. As amostras foram submetidas à análise no NIR e os espectros foram gerados por meio do detector FT-IR. Para a construção do modelo de calibração foi utilizado o método de classificação multivariada por mínimos quadrados parciais com análise discriminante (PLS-DA), em que as classes (y) são as variáveis dependentes e os espectros obtidos das amostras as variáveis independentes. As cultivares de girassol foram diferenciadas, tanto óleo quanto semente. Por óleo obteve-se 100% de acerto na calibração, 92% no teste de y-randomization, 86% na validação cruzada e 92% na validação externa, em que se testa 25% das amostras para validar o modelo. E por sementes 100% de acerto na calibração, 87% no teste de y-randomization, 100% na validação cruzada e 100% na validação externa. Portanto, conclui-se que a técnica de espectroscopia no infravermelho próximo, associada à análise multivariada, diferencia cultivares de girassol, tanto por meio do óleo, extraído de semente com pericarpo e de semente sem pericarpo, quanto por semente, com e sem pericarpo.

Non-Destructive Genotyping of Cultivars and Strains of Sesame through NIR Spectroscopy and Chemometrics

“…Sesame seeds have several varieties and cultivars, which have characteristics for specific needs, such as the resistance to pests and edaphoclimatic conditions [ 10 ]. A good and new cultivar must have characteristics different from the others existing ones, and those characteristics must remain for successive generations [ 11 , 12 , 13 ].…”

“…The differentiation of cultivars is performed by means of morphological descriptors, in addition to molecular markers, which is performed by the study of DNA [ 10 ]. Among these markers, the most used are: RFLP (restriction fragment length polymorphism), AFLP (amplified fragment length polymorphism), RAPD (random amplification of polymorphic DNA) and microsatellites (ISSR—inter simple sequence repeats; SSR—simple sequence repeats) [ 12 , 14 ].…”

“…The differentiation of cultivars is performed by means of morphological descriptors, in addition to molecular markers, which is performed by the study of DNA [ 10 ]. Among these markers, the most used are: RFLP (restriction fragment length polymorphism), AFLP (amplified fragment length polymorphism), RAPD (random amplification of polymorphic DNA) and microsatellites (ISSR—inter simple sequence repeats; SSR—simple sequence repeats) [ 12 , 14 ]. In general, the procedure for identifying some cultivars is carried out by planting the seed and, at least, one month is expected to pass so that, through their growth and development, their morphological identification occurs [ 15 ].…”

“…The molecular analysis method also has the disadvantages of being destructive and requiring expensive reagents that generate waste. In addition, these techniques require professionals with technical qualifications [ 10 ].…”

“…Infrared spectroscopy in the NIR region is considered a powerful tool for the quantitative and qualitative analysis of chemical and physical variables, and can be applied to samples of various types, such as from the pharmaceutical, polymer, petrochemical, food and agricultural industries [ 15 , 16 ]. However, in order to obtain results from the interactions with the analyte (seeds and grains), the development of chemometric models is required [ 12 , 17 ]. These techniques refer to mathematical models and methods and, among these, multivariate statistics, which consider the correlation between many variables analyzed simultaneously, allowing the extraction of a much greater amount of information.…”