Relationship of dielectric properties of the hair cover with its morphophysiological and biochemical characteristics in farmed fur-bearing animals

The hair cover of furbearing animals is a dielectric material able to electrify with accumulation of static electricity charges. Electrically charged surface attracts dust particles causing loss of fur shine, accelerated aging, destruction and a decrease in strength characteristics and the quality of raw materials, as well as the transfer of static electricity charges when in contact, for example, with the human body. In this paper, for the first time, we propose an empirical equation describing the dielectric properties of natural fur and the interrelations between the composition and quality of the skin and hair covers with its electrophysical characteristics for different species of furbearing farm animals. The work aimed to study the influence of morphophysiological characteristics, biochemical composition (mineral and amino acid), and the state of the skin and hair on dielectric properties and to reveal relationships to more correctly assess the quality of fur raw materials. In the work, we used fur raw materials obtained from physiologically healthy silver-black foxes ( Vulpes vulpes ), silver foxes ( Alopex lagopus ), and standard minks ( Mustela vison ) (Zverosovkhoz Saltykovsky, Moscow Province). Hair density per 1 cm2 rump, the guard hair density per 1 cm2 rump, the linear dimensions of various types of hair, their thickness, the thickness of the rump skin, and the pelt area were measured and Na, Ni, B, V, Se, Al, Fe, K, I, Ca, Co, Mg, Mn, Cu, P, Cr, Zn, Si contents were determined. Amino acid analysis of biosubstrate hydrolysates was carried out for 17 amino acids. The pelts were tested for dielectric properties. The discharge kinetics equations were obtained at 20° C, 62 % relative humidity and voltage of 10.0, 18.5, and 28.5 kV (a HT-705 5kVA 50KV AC/DC high-voltage charge generator, Wuhan Huatian Electric Power Automation Co., Ltd., China). When assessing the quality of fur raw materials, a voltage of 9.5, 12.5, 15.5 and 18.5 kV was used. The charge leakage time constant and the change in the magnitude of the static electric field intensity at certain time intervals were determined. A comparison of the morphophysiological parameters of the skin and hair in different species of furbearing animals with the data on electrizability allowed us to derive an empirical equation reflecting the dielectric properties of the skin and hair - E = E0∕е-t/τ, where E0 is the maximum value of the tension and τ is the charge leakage time constant. Correlation analysis showed close interrelations between the rate of charge runoff and the length and thickness of the guard hairs ( r = 0.83-0.90 at p 0 value closely correlated with the total mass of elements in the hair and skin, and with the amino acid composition of the hair cover ( r = 0.90; r = 0.86; r = 0.99 at p 0). Decreased fur density, haircut, broken awn, fur mattedness reduce the E0 index by 25-90 % and change the charge leakage time constant τ by 15-70 % compared to defect-free skins. The dielectric parameters E0 and τ provide more accurate fur quality estimates in silver-black fox, silver fox, and standard mink. The technology uses electrophysical measurements instead of not subjective organoleptic analysis.