Validation study of a rapid colorimetric method for the determination of phytic acid and inorganic phosphorus from seeds

Abstract

Phytate, as an important mineral storage compound in seeds, is vital for seed/grain development; it is often considered to be an antinutritional substance. The objective of this study was to develop a rapid and inexpensive colorimetric method of measuring phytate and inorganic P (Pi) concentrations from maize, soybean and sunflower seed/grain extracts, by combining adequate precision and simplicity, ideal for breeders interested in improving simultaneously Pi and phytate levels. The investigated extraction mediums: double distilled (DD) H2O, 2.4 % HCl and 5 % trichloracetic acid (TCA) were proved to be suitable for the analysis of phytic acid and inorganic phosphorus in seed extracts. The advantages of 5 % TCA over to DD H2O and 2.4 % HCl were reflected through the low limit of detection for both phytic acid and Pi and good recovery with low bias. A low detection limit for Pi is important for samples with naturally low Pi concentrations, such as soybean seeds.

Fitat je važan za razvoj semena i služi za skladištenje minerala. On se uglavnom smatra za antinutritivnu supstancu. Cilj istraživanja je bio da se razvije brza i jeftina kolorimetrijska metoda za merenje koncentracije fitata i neorganskog fosfora (Pi) iz ekstrakta semena kukuruza, soje i suncokreta, kombinujući određenu preciznost i jednostavnost, idealne za selekcionere zainte- resovane za istovremeno poboljšanje odnosa Pi i fitata u semenu. Ispitivana ekstrakciona sredstva: bidestilovana voda (DD H2O), 2,4 % HCl i 5 % trihlorsirćetna kiselina (TCA) su se pokazale pogodnim za analizu fitinske kiseline i Pi iz ekstrakta semena. Prednost 5 % TCA u odnosu na DD H2O i 2,4 % HCl se ogleda u niskoj granici detekcije za fitinsku kiselinu i Pi, dobrom recoveryju i niskim vrednostima odstupanja (bias). Niska granica detekcije za Pi je važna za uzorke sa prirodno niskom Pi koncentracijom, kao što je seme soje.