Synergistic Effects of Azospirillum brasilense and Nitrogen Doses on Wheat Flour Characteristics and Yields of Reducing Sugars Obtained by Subcritical Water Hydrolysis from Bran

Abstract

The synergistic interactions between nitrogen doses and microbial inoculation in crops indicate the potential for integrated nutrient management strategies in plant cultivation. Therefore, this study investigated the interactive effects of nitrogen doses and Azospirillum brasilense inoculation on wheat flour characteristics in terms of the falling number and color parameters and yields of reducing sugars obtained by subcritical water hydrolysis (SWH) from wheat bran. The strip-plot experimental design, bifactorial with three replications, was applied. Factor A was three wheat cultivars: ORS Agile (AGI), ORS Feroz (FER), and TSZ Dominadore (DOM). Factor D was five nitrogen doses in the topdressing: 0, 20, 40, 60, and 80 kg ha−1. The lowest value of falling number of 332 s was achieved with flour from FER cultivar using a nitrogen dose of 80 kg ha−1 with A. brasilense inoculation. The SWH produced yields of reducing sugars (YRS) from wheat bran of up to 6.74 ± 0.18 g (100 g of wheat bran)−1 for the cultivar DOM when using a nitrogen dose of 60 kg ha−1 associated with A. brasilense inoculation. In this cultivation condition, the falling number was 408 s and the color parameters were L* of 92.49, a* of −0.26, and b* of 11.91. In the other conditions, the YRS ranged from 2.93 ± 0.63 to 6.52 ± 0.04 g (100 g of wheat bran)−1. Both flour and bran are nutritional products with high application potential, and this study indicated SWH as a promising technique to dissociate the lignocellulosic complex of wheat bran without using hazardous solvents.