Abstract
This study investigated the potential of ball milling as a dry process for in situ
production of arabinoxylan oligosaccharides (AXOS) in arabinoxylan
(AX)-rich wheat and rye bran. An extensive lab-scale ball mill treatment
(120 h, 50% jar volume capacity) increased the wheat bran
water-extractable arabinoxylan (WE-AX) level from 4% (untreated bran) to
61% of the wheat bran AX. Extractable AX fragments had an
arabinose/xylose ratio (A/X ratio) of 0.72 and a molecular mass (MM) of
15 kDa. Ball milling of rye bran gave rise to similar results, with the
A/X ratio of the extractable AX being considerably lower (0.51).
Optimization of the ball mill treatment by varying the degree of filling
of the milling jar permitted us to obtain equally high WE-AX levels
(>70%) in wheat and rye bran within a 24 h ball-milling period. Ball
milling at optimal conditions (24 h, 16% jar volume capacity) yielded
wheat bran AXOS, with an A/X ratio of 0.65 and a MM of 6 kDa. Ball
milling (24 h, 50% jar volume capacity) of pericarp-enriched wheat bran
increased the WE-AX level from 1% (untreated pericarp) to 63%. The
extractable material had a high A/X ratio (0.97) and a low MM (5 kDa).
Fluorescence microscopy revealed that the extensive ball mill treatment
led to the almost complete disappearance of discernible tissue
structures in the ball-milled material, indicating bran particle size
reductions down to the nanoscale level. It further visualized the
aggregation of the treated material. These results show that AXOS can be
produced in situ from wheat or rye bran in a single-stage dry
milling process, rendering a wet extraction step redundant. The higher
A/X ratio of the obtained AXOS than of enzymically produced wheat
bran-derived AXOS offers perspectives for the production of a wide range
of AXOS structures. Moreover, ball milling makes upgrading of the
low-value pericarp layer feasible.
Original language | English |
---|---|
Pages (from-to) | 8467-8473 |
Number of pages | 7 |
Journal | Journal of Agricultural and Food Chemistry |
Volume | 57 |
Issue number | 18 |
DOIs | |
Publication status | Published - Sept 2009 |
MoE publication type | A1 Journal article-refereed |
Keywords
- Arabinose
- Arabinose: analysis
- Dietary Fiber
- Dietary Fiber: analysis
- Food Handling
- Food Handling: methods
- Oligosaccharides
- Oligosaccharides: chemistry
- Particle Size
- Secale cereale
- Secale cereale: chemistry
- Secale cereale: ultrastructure
- Seeds
- Seeds: chemistry
- Seeds: ultrastructure
- Triticum
- Triticum: chemistry
- Triticum: ultrastructure
- Xylans
- Xylans: analysis
- Xylans: chemistry
- Xylose
- Xylose: analysis