Regenerated Fibers from Rennet-Treated Casein Micelles during Acidification
Micellar casein fibers of defined size and internal structure can be produced by the extrusion of cold-renneted casein micelles into a warm, calcium-rich coagulation bath. Calcium phosphate contacts within the casein matrix are important for fiber stability and production but become less important u...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-07-01
|
| Series: | Gels |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2310-2861/9/7/538 |
| _version_ | 1827732928043417600 |
|---|---|
| author | Ronald Gebhardt Novin Darvishsefat |
| author_facet | Ronald Gebhardt Novin Darvishsefat |
| author_sort | Ronald Gebhardt |
| collection | DOAJ |
| description | Micellar casein fibers of defined size and internal structure can be produced by the extrusion of cold-renneted casein micelles into a warm, calcium-rich coagulation bath. Calcium phosphate contacts within the casein matrix are important for fiber stability and production but become less important under acidic pH conditions. We demonstrate this with swelling experiments in media with pH < 2, which we adjust with citric acid of different molarities. In contrast to the simple swelling of dried casein fibers in water, a two-phase process takes place in citric acid similar to swelling in 1 N HCl. However, instead of a second deswelling step, we observe in citric acid that the fiber swells further. The observation is explained by a pH-dependent transition from a rennet casein gel to an acidified rennet gel. This can be simulated with a kinetic model that couples two second-order rate equations via a time-varying ratio. The final swelling values decrease with increasing proton concentration via a scaling relation, which is also confirmed by swelling in other acids (HCl or acetic acid) in this pH range. We attribute this to a decrease in the molecular weights of the aggregated casein structures within the strands of the gel network. |
| first_indexed | 2024-03-11T01:02:52Z |
| format | Article |
| id | doaj.art-97e42afec6084e5eb7f6ea4c06a53e3e |
| institution | Directory Open Access Journal |
| issn | 2310-2861 |
| language | English |
| last_indexed | 2024-03-11T01:02:52Z |
| publishDate | 2023-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Gels |
| spelling | doaj.art-97e42afec6084e5eb7f6ea4c06a53e3e2023-11-18T19:27:35ZengMDPI AGGels2310-28612023-07-019753810.3390/gels9070538Regenerated Fibers from Rennet-Treated Casein Micelles during AcidificationRonald Gebhardt0Novin Darvishsefat1Chair of Soft Matter Process Engineering (AVT.SMP), RWTH Aachen University, 52062 Aachen, GermanyChair of Soft Matter Process Engineering (AVT.SMP), RWTH Aachen University, 52062 Aachen, GermanyMicellar casein fibers of defined size and internal structure can be produced by the extrusion of cold-renneted casein micelles into a warm, calcium-rich coagulation bath. Calcium phosphate contacts within the casein matrix are important for fiber stability and production but become less important under acidic pH conditions. We demonstrate this with swelling experiments in media with pH < 2, which we adjust with citric acid of different molarities. In contrast to the simple swelling of dried casein fibers in water, a two-phase process takes place in citric acid similar to swelling in 1 N HCl. However, instead of a second deswelling step, we observe in citric acid that the fiber swells further. The observation is explained by a pH-dependent transition from a rennet casein gel to an acidified rennet gel. This can be simulated with a kinetic model that couples two second-order rate equations via a time-varying ratio. The final swelling values decrease with increasing proton concentration via a scaling relation, which is also confirmed by swelling in other acids (HCl or acetic acid) in this pH range. We attribute this to a decrease in the molecular weights of the aggregated casein structures within the strands of the gel network.https://www.mdpi.com/2310-2861/9/7/538casein fiberswellingmilk gels |
| spellingShingle | Ronald Gebhardt Novin Darvishsefat Regenerated Fibers from Rennet-Treated Casein Micelles during Acidification Gels casein fiber swelling milk gels |
| title | Regenerated Fibers from Rennet-Treated Casein Micelles during Acidification |
| title_full | Regenerated Fibers from Rennet-Treated Casein Micelles during Acidification |
| title_fullStr | Regenerated Fibers from Rennet-Treated Casein Micelles during Acidification |
| title_full_unstemmed | Regenerated Fibers from Rennet-Treated Casein Micelles during Acidification |
| title_short | Regenerated Fibers from Rennet-Treated Casein Micelles during Acidification |
| title_sort | regenerated fibers from rennet treated casein micelles during acidification |
| topic | casein fiber swelling milk gels |
| url | https://www.mdpi.com/2310-2861/9/7/538 |
| work_keys_str_mv | AT ronaldgebhardt regeneratedfibersfromrennettreatedcaseinmicellesduringacidification AT novindarvishsefat regeneratedfibersfromrennettreatedcaseinmicellesduringacidification |