Morphological modification of starch - New separating and carrier materials

Transcription

1 57. Starch Convention, Detmold, Morphological modification of starch - New separating and carrier materials B. Volkert, C. Fanter, W. Wagenknecht, R. Leibnitz

2 Content 1. Initial situation 2. Task and aims 3. Methods of characterization - chemical, - biochemical, - and physical treatment of starch 5. Conclusion

3 1. Initial situation Filtration behaviour of native starches 10 Turbidity [EBC] potato starch diatomite corn starch rice starch amylomaize Time of filtration [min]

4 2. Task and aims Tasks and aims Replacement of diatomite by starch products Variation of the particle size distribution Adjustable porosity Method-development of stabilization and fixation of the structure

5 3. Methods of characterization Methods of characterization swelling behaviour, water retention value (WRV) volume of sedimentation porosity, mercury porosimeter morphology, REM particle-size distribution filtration behaviour

6 Transformation/Deformation of starch grain structure Initial products: potato, rice, corn, amylomaize starch Modification: chemical treatment physical treatment enzymatic treatment reaction/ aggregation of starch grains with binders physical treatment chemical treatment chemical treatment

7 Chemical and physical modification (1) cross-linking + jet-cooker (2) cross-linking + high pressure homogenizer (3) cross-linking C + ultraturrax

8 Volume of sedimentation of cross-linked starch Cross-linking molar ratio Potato starch Amylomaize 0,04 n NaOH 0,04 n NaOH AGU : Epichlorohydrin : NaOH Cold-swelling [ml/g] Hot-swelling [ml/g] Cold-swelling [ml/g] Hot-swelling [ml/g] native starch 1,5 paste 1,6 paste 1 : 0,005 : 0,05 1,65 8,95 1,9 7,7 1 : 0,01 : 0,05 1,65 6,8 1,8 5,85 1 : 0,05 : 0,06 1,7 4,9 2,0 3,0 1 : 0,1 : 0,12 1,8 3,9 2,0 2,65

9 Physical and chemical modification (1) High pressure homogenizer + cross-linking (2) Jet-cooker + cross-linking

10 REM: High pressure homogenizer (+ cross-linking) amoylomaize, 700 bar, 60 C nearly unchanged starch grains

11 Water retention value WRV cold WRV hot WRV [%] molar ratio starch : epi = 1 : x 0 potato L150101Jet V V020218pT V V V020219Jet P ,1 + 0,1 0 0,01 0,0025 0,1

12 Summary: Chemical and physical modification different swelling states of starches were adjusted by using different weakly concentrated sodium hydroxide solutions these swelling states were fixed by cross-linking the products get more resistant against hot water by increasing of cross-linking the porosity increases and the swelling behaviour decreases slightly cross-linked potato starch formed ring structures in the high pressure homogenizer unmodified starch could be dissolved from cross-linked structures to give holes complete physical deformation of the grain structure followed by cross-linking results irregular particles

13 Enzymatic degradation and silanization of starch starch buffer solution amylase mixing ph 5 ca. 6 d 40 C stoppage of the reaction ph to 3 HCl filtration, washing H 2 O (evtl. drying 60 C) 80 % EtOH silanization 2 h at RT ph 8 NaOH PTMS EtOH drying 60 C enzymed starch

14 REM: Enzymatic and chemical treatment corn starch, aspergillus oryzae, 6 d, 40 C formation of pores and holes

15 Porosity after enzyme treatment of corn starch JL130902: 10 ml BAN 240, 65 C JL160902: 5 ml BAN 240, 65 C JL190902: 10 ml BAN 480, 65 C JL230902: 5 ml BAN 480, 55 C total pore volume [mm³/g] JL JL JL JL time [h]

16 Summary: Enzymatic and chemical treatment depending on the type of enzyme, the reaction time and temperature it is possible to obtain - grain starch with pinholes or - high degraded grains with irregular structure

17 Reaction/aggregation of starch grains with binders neutral individual particle Glycidyloxypropyltrimethoxysilane (GPS) particle associate secondary structure Coating with cellulose acetate cationic Epichlorohydrin Aminopropyltriethoxysilane (APS) Polyethylenimine (PEI) Coating with Resamin anionic Phosphates Water-glass/Phosphate Coating with Madurit

18 Coating with cellulose-2,5-acetate starch 2,5 CA acetone solution of CA, stir in of starch dispersion in water, ultraturrax H 2 O filtration EtOH-washing ethanol separation of acetone/etoh/h 2 O starch-ca-hybrid

19 Volume of sedimentation and WRV of coated starch Sample SV (ml/g) cold SV (ml/g) hot WRV (%) cold WRV (%) hot V amylomaize : CA = 1 : 0,025 3,43 2 9,38 99,8 165 V amylomaize : CA = 1 : 0,062 3, , V amylomaize : CA = 1 : 0,125 3, ,73 96,3 201 V potato starch : CA = 1 : 0,062 5,63 20,71 91,9 n.b. 1 V rice starch : CA = 1 : 0,062 2, ,56 93,7 271 V corn starch : CA = 1 : 0,062 1, ,63 67, swelling was to strong 2 mixture of solid and gas bubbles swum on surface

20 Coating with wet-strength agents starch Resamin water mixing ca. 10 min 20 C pre-drying 2h 60 C drying 1 h 105 C sieving < 80 μ (grinding) strach-resaminhybrid

21 Filtration behaviour of amylomaize and corn starch after coating with Resamin 3 2,5 Native corn starch Turbidity [EBC] 2 1,5 1 0,5 0 Native amylomaize 0,5% 0,5% 1% 1,5% 3% 3% 2% 2% 1% 1,5% Time of filtration [min]

22 Influence of the particle-size distribution on filtration time grinding and classification Diameter of 50 % [µm] 07:00 Amount of fine particles 06:00 <4 µm [%] 7,5 µm 27% Time of filtration [mm:ss] 05:00 04:00 03:00 02:00 01:00 9,5µm 9% 12,5% 15 µm 13µm / 13% 21% 21µm 00: Amount of fine particles [%], Diameter of 50 % [µm]

23 Grinding and sieve analysis of amylomaize after coating with Resamin Grinding with a centrifugal mill (Retsch) coarse grinding (2mm) 1x Retsch (500µm) 2x Retsch (500µm) 3x Retsch (500µm) Distribution of mass 100,00% 80,00% 60,00% 40,00% 20,00% 0,00% < Particle-size range [µm]

24 Summary: Reaction/aggregation of starch grains no complete envelopment by coating with cellulose acetate formation of starch grain agglomerates by coating with resins filtration performance is controllable by selective addition of resin

25 5. Conclusion Conclusion formation of irregular starch based structures are possible by different ways - high pressure homogenizer - jet-cooker - ultraturrax - enzymes these structures have to be stabilized by cross-linking for example best filtration performance of irregular structures is obtained by coating with resins the particle size distribution has a significant influence on filtration behaviour