The Use of a Non-Invasive Electrical Method to Assess the Chemical Composition, Hardness, and Color of Durum Wheat Grain Cultivated in an Integrated System

Electrical properties are the least known and described among the physical properties of food products. The most widespread practical directions of their use include moisture measurements as well as dielectric and microwave heating. Less frequently, they are used to assess the physicochemical parameters of food products, including the technological features of cereal grains. Earlier research by the authors of this paper demonstrated the possibility of using an RCC substitute model of food products (conductivity and capacitance parameters) to identify the grain variety, geometric features, level of grain damage as well as grain moisture content. This model can also be used to distinguish cereal species as well as to assess the proximate chemical composition of their grain. The promising results obtained in this area encouraged us to expand the research with a material important from the food market perspective—durum wheat, obtained in the conditions of sustainable cultivation in north-eastern Europe (temperate climate). The study material was obtained from a proprietary sustainable production technology designed in a strict field experiment. The aim of this research was: (1) to assess the effect of an integrated cultivation system of native durum wheat (six variants), differentiated by a nitrogen fertilization dose (0, 80, 120 kg·ha −1 ) and with and without growth regulator (GR, WGR) on changes in selected quality parameters (protein, lipid, and starch contents; hardness; color) and electrical parameters (Z, Cp, Cs) of the grain; and (2) to determine the correlations between the examined quality traits and electrical properties of the grain to indicate the possibility of using a non-invasive electrical method to assess grain quality. The highest contents of starch and total lipids and the highest grain hardness were obtained in the cultivation variants GR + 0N and WGR + 0N, whereas the highest protein content—upon wheat fertilization with 120N. The study demonstrated a different strength of the correlations between the tested parameters depending on the cultivation method. In the WGR + 0N variant (environmentally friendly), the strongest correlation between grain quality traits and electrical properties was obtained for both the conductive (Z) and capacitive (Cp, Cs) parameters in the entire analyzed range of current frequencies. The cultivation of durum wheat in the integrated system, especially in the WGR variant, facilitates grain quality modeling and enables using a non-invasive electrical method for a rapid assessment of the quality traits of the grain while raising no concerns over natural environment safety. The growth regulator (GR) application during native durum wheat cultivation hampers the use of the analyzed electrical method to assess its grain quality.