Topic
Finings
About: Finings is a research topic. Over the lifetime, 38 publications have been published within this topic receiving 381 citations.
Papers
TL;DR: The results imply that there is a limited amount of phlorotannins that can bind to a given amount of PVPP, and that it is preferable to use low quantities of P VPP repeatedly, compared to using fewer treatments with a high amount ofPVPP.
Abstract: Tannins, a large and diverse group of phenolic secondary metabolites, are common in terrestrial plants and marine brown algae. It is sometimes desirable to remove the tannins from plant or algal extracts, e.g., when isolating enzymes and nucleic acids, when using certain colorimetric methods to quantify the tannin content, or to create reliable controls when using tannins in experimental studies. Insoluble polyvinylpolypyrrolidone (PVPP) can be used to specifically remove tannins from solution. In the present study, we evaluated the effect of different factors (amount of PVPP, number of PVPP treatments, type of solvent, pH, and incubation time) on the PVPP removal of dissolved brown algal phlorotannins. Our results imply that there is a limited amount of phlorotannins that can bind to a given amount of PVPP, and that it is preferable to use low quantities of PVPP repeatedly, compared to using fewer treatments with a high amount of PVPP. Furthermore, we found no consistent effect on the removal of phlorotannins due to solvent type (acetone, methanol, distilled water or filtered seawater). There was a slight decrease in the amount of phlorotannins removed from extracts with increasing pH when repeatedly treated with PVPP. All phlorotannins were removed from extracts with pH ≤6.2, and 89% of the initial phlorotannin content was removed at pH 9.7. These results are compared with previous methodological studies on tannin removal with PVPP. Furthermore, the implications of phlorotannin removal in analytical and ecological investigations are discussed.
79 citations
TL;DR: In this article, the authors used polyvinylpolypyrrolidone (PVPP) or a polyvinelpyrrinolidone modified silica gel to remove haze sensitive glycoproteins from malt and lager beers.
Abstract: Colloidal stabilisation of all malt and adjunct lager beers through selective removal of haze sensitive glycoproteins using silica gel and tannoid polyphenols using polyvinylpolypyrrolidone (PVPP) or a polyvinylpyrrolidone (PVP)-modified silica gel has been demonstrated during full brewery production. At this scale PVPP and the PVP-modified silica gel exhibited equivalent binding capability for tannoid polyphenols although PVPP removed additional polyphenolic species. Characterisation of proanthocyanidins following treatment at 4°C with PVPP and the PVP-modified silica gel silica co-product confirmed that PVPP removes a wider range of polyphenolics. Both products exhibited poorer polyphenolic binding capability at 4°C as would be expected for a physical adsorption process.
52 citations
TL;DR: The method described in the present study to remove polyphenol is simple, inexpensive, rapid, and efficient and can be employed to investigate the contribution of polyphenols present in natural products to their biological activity.
Abstract: Polyphenols are secondary metabolites of plants, which are responsible for prevention of many diseases. Polyvinylpolypyrrolidone (PVPP) has a high affinity towards polyphenols. This method involves the use of PVPP column to remove polyphenols under centrifugal force. Standards of gallic acid, epigallocatechin gallate, vanillin, and tea extracts (Camellia sinensis) were used in this study. PVPP powder was packed in a syringe with different quantities. The test samples were layered over the PVPP column and subjected to centrifugation. Supernatant was tested for the total phenol content. The presence of phenolic compounds and caffeine was screened by HPLC and measuring the absorbance at 280. The antioxidant capacity of standards and tea extracts was compared with the polyphenol removed fractions using DPPH scavenging assay. No polyphenols were found in polyphenolic standards or tea extracts after PVPP treatment. The method described in the present study to remove polyphenols is simple, inexpensive, rapid, and efficient and can be employed to investigate the contribution of polyphenols present in natural products to their biological activity.
23 citations
TL;DR: The intrinsic viscosities of collagen finings were found to be higher in the absence of citrate buffer than in its presence as mentioned in this paper, and the effect of the rate of flow in the viscosity measurements was considered.
Abstract: The intrinsic viscosities of collagen finings were higher in the absence of citrate buffer than in its presence. The lower values, which vary among different preparations, well reflect their relative fining abilities. The latter are due to molecules which are, in most cases, larger than monomers, and the differences in intrinsic viscosity are ascribed to differences in molecular structure in the original tissues. The higher values observed in the absence of citrate are due to the aggregation of these molecules; however, these dissociate in beer and so do not assist fining in this form. The effect of the rate of flow in the viscosity measurements is considered.
Differences in the shrinkage temperature of isinglass are related to differences in macrostructure, but these are not necessarily related to the stability of the protein in solution. The denaturation temperatures (TD° C) of all the finings examined were in the range 29·2–30·3° C.
16 citations
Journal Article•
TL;DR: Kieselsol, a generic name for an aqueous colloidal suspension of silicon dioxide, was first used in Germany as a fining agent in conjunction with gelatin during World War II, when tannin was unobtainable as discussed by the authors.
Abstract: "Kieselsol," a generic name for an aqueous colloidal suspension of silicon dioxide, was first used in Germany as a fining agent in conjunction with gelatin during World War II, when tannin was unobtainable. It fell into disuse until recently, when a review of its physical and chemical characteristics indicated that it would be a useful and desirable substitute for tannin in wine and fruit-juice fining. Freshly fermented apple wine was employed in a comparison between tannin-gelatin and Kieselsolgelatin finings.
13 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2017 | 2 |
| 2016 | 1 |
| 2015 | 2 |
| 2014 | 1 |
| 2012 | 1 |
| 2011 | 2 |