Cellulose
problem from industrial mills by providing a solution for cereal processing by-products use. Finally, control of the biodegradability rate of manufactured products allows predicting their use phase performance and duration of deterioration.
composition of brans used in this study was researched by Modzelewska and Adamska (2006) and is summa- rized in Table 4. The differences in extractives content augmented with the bran share increase. It is an additional dilution effect of mixing compo- nents present in waste paper and bran. The bran itself contains several solvable substances that are con- tributing to the overall content of extractives. These, beside of cellulose include ash, dietary fibre, proteins, starch and diverse phytochemicals, among the others (Onipe et al. 2015). The relatively high amount of starch in cereal bran (estimated to be 15.8–18.9% of the dry mass) simplifies the coupling of cellulose fibres and paper forming as well as aids in filling micro-pores. However, as previously reported by the authors, the presence of starch in paper products may advance the degradation rate as it is a favourable breeding ground for bacteria and microfungi (Sandak et al. 2011). NIR analysis of investigated papers with addition of the rye and wheat brans did not reveal any noteworthy differences between spectra due to presence of bran fillers (Sandak et al. 2011). Only slight variations were noticed for CH, CH 2 and OH functional groups assigned to cellulose and holocellulose.
Effect of the bran additives on the properties of investigated paper products before degradation
The effect of additives on the chemical composition of manufactured paper products is summarized in Table 3. The effect was minor, but for all analysed components the differences between means were statistically significant (ANOVA, p \ 0.05). The most noticeable differences are in cellulose content (88.6–91.2%). Cellulose content in control samples was highest and with increased amount of bran (both types) diminished. It was a direct effect of dilution, as the amount of cellulose is low in bran when compare to the pulp and paper. The cellulose content in bran as reported in literature ranges between 5 and 13% (Kamal-Eldin et al. 2009; Chalamacharla et al. 2018). In fact, such a high variation in composition within both wheat and rye brans is influenced by the cereal species, provenance, batch and milling techniques applied for flour production. The chemical
Table 3 Chemical composition of papers (% of dry mass) estimated before and after degradation in agricultural soil
Paper type Before degradation
After degradation in agricultural soil
Cellulose* Extractives
PD Cellulose* Extractives
PD
H 2 O* 1% NaOH* 1% H 2 SO 4 *
H 2 O* 1% NaOH* 1% H 2 SO 4 *
SD
0.1
0.1
0.1
0.1
–
0.1
0.1
0.1
0.1
–
91.2 d
2.4 a
15.1 a 15.5 b 16.7 d
10.2 a 10.5 b 12.7 d 11.5 c 12.5 d
1102 83.5 d 1100 82.0 c 1097 76.9 b 1101 77.1 b 1097 76.2 a
2.8 a
16.0 b 15.8 ab 15.7 a 15.9 ab 15.7 a
13.8 b 13.6 ab 13.5 a 13.4 a 13.5 a
WP
949
WP3W 90.0 c WP5W 89.6 b WP3R 90.0 c WP5R 88.6 a
2.9 cd
3.3 bc
954
3.1 d
3.5 c 3.2 b
950
2.5 ab 2.7 bc
16.5 cd
955
16.3 c
3.4 bc
954
*Differences significant at p \ 0.05, letters in superscript correspond to the statistically similar groups determined with Tukey post hoc test SD, maximum standard deviation of results; PD, polymerization degree
Table 4 Chemical composition (% of dry mass) of rye and wheat bran
Bran type Cellulose Holocellulose Starch Lignin Hot water extractives
Cold water extractives
Ash
Wheat
12.7
43.1
18.9
10.4
25.8
25.1
3.7
Rye
10.5
20.8
15.8
9.3
44.5
26.6
3.5
123
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