Impact of organic fertilization on physicochemical and functional properties of cassava starch

摘要

Organic fertilizers were applied to cassava plants and the effect on the physicochemical and functional characteristics of the starch was evaluated. We used a full-factorial design (2(3)) with three organic fertilizers as factors: liquid bioferment (LB), vermicompost leachate (VL), and bacterial complex (BC, mixture of bacteria Pseudomonas fluorescens, Bacillus subtilis, and Azospirillum spp.). The leaf area and the chlorophyll content of leaves exhibited similar behavior. BC-LB treatment promoted higher values in both variables. Tubers from BC-VL treatment had the highest moisture content (73.87%). The ash content showed no significant difference (p>0.05) among treatments. The protein content ranged from 0.87 (VL) to 2.27% (BC). The content of NFE presented negative linear correlation (R-2 = -0.746) in fiber content for all treatments, LB-VL being the treatment with higher carbohydrate content and lower crude fiber. Only the BC fertilization promoted a higher proportion (similar to 50%) of granule size between 5 and 10mm. BC-VL treatment showed significantly (p0.05) higher swelling power, solubility, and water absorption capacity when compared to the other treatments at 80 and 90 degrees C, while syneresis was not seen to be affected. This behavior was verified by principal component analysis (PCA). The first three components showed two important associations; (i) between BC and BC-VL treatments and functional properties of starch at 90 degrees C and (ii) between the LB and BC-LB treatments and the leaf size, chlorophyll content of leaves, and starch recovered.