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Proteins In Wine
Proteins are present in wine. The most common proteins include thaumatin-like proteins and chitinases and have a role in the formation of turbidity (haze) especially visible in white wine. The quantity of haze forming is dependent on the quantity of phenolics in the wine. Some of those proteins are considered nuisance. Some of them are grape pathogenesis-related proteins. Those proteins have been identified by mass spectrometry and originate from grape, yeast, bacteria and fungi. These proteins are unstable when submitted to heat, and can be removed by treatment using bentonite, a process that contributes to the clarification and stabilization of wine. Proteins residues from proteinaceous fining agents such as gelatin or egg white can possibly be found in wine. Wheat gluten has also been tested, but there are health issues regarding its use because of gluten intolerance in some people. See also * Wine chemistry * Protein adsorption in the food industry Protein adsorption refe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bentonite
Bentonite () is an absorbent swelling clay consisting mostly of montmorillonite (a type of smectite) which can either be Na-montmorillonite or Ca-montmorillonite. Na-montmorillonite has a considerably greater swelling capacity than Ca-montmorillonite. Bentonite usually forms from the weathering of volcanic ash in seawater, or by hydrothermal circulation through the porosity of volcanic ash beds, which converts (devitrification) the volcanic glass ( obsidian, rhyolite, dacite) present in the ash into clay minerals. In the mineral alteration process, a large fraction (up to 40-50 wt.%) of amorphous silica is dissolved and leached away, leaving the bentonite deposit in place. Bentonite beds are white or pale blue or green (traces of reduced ) in fresh exposures, turning to a cream color and then yellow, red, or brown (traces of oxidized ) as the exposure is weathered further. As a swelling clay, bentonite has the ability to absorb large quantities of water, which increa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Adsorption In The Food Industry
Protein adsorption refers to the adhesion of proteins to solid surfaces. This phenomenon is an important issue in the food processing industry, particularly in milk processing and wine making, wine and beer making. Excessive adsorption, or protein fouling, can lead to health and sanitation issues, as the adsorbed protein is very difficult to clean and can harbor bacteria, as is the case in biofilms. Product quality can be adversely affected if the adsorbed material interferes with processing steps, like pasteurization. However, in some cases protein adsorption is used to improve food quality, as is the case in Finings, fining of wines. Protein adsorption Protein adsorption and protein fouling can cause major problems in the food industry (particularly the dairy industry) when proteins from food adsorb to processing surfaces, such as stainless steel or plastic (e.g. polypropylene). Protein fouling is the gathering of protein aggregates on a surface. This is most common in heating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wine Chemistry
Wine is a complex mixture of chemical compounds in a hydro-alcoholic solution with a pH around 4. The chemistry of wine and its resultant quality depend on achieving a balance between three aspects of the berries used to make the wine: their sugar content, acidity and the presence of secondary compounds. Vines store sugar in grapes through photosynthesis, and acids break down as grapes ripen. Secondary compounds are also stored in the course of the season. Anthocyanins give grapes a red color and protection against ultraviolet light. Tannins add bitterness and astringency which acts to defend vines against pests and grazing animals. Environmental factors such as soil, rainfall and fog affect flavor in ways that can be described collectively as "character" or the French term “terroir”. As climate change disrupts long-established patterns of temperature and precipitation in wine-growing regions and causes more extreme weather events, the rate at which sugars, acids and seconda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gluten Intolerance
Gluten-related disorders is the term for the diseases triggered by gluten, including celiac disease (CD), non-celiac gluten sensitivity (NCGS), gluten ataxia, dermatitis herpetiformis (DH) and wheat allergy. The umbrella category has also been referred to as gluten intolerance, though a multi-disciplinary physician-led study, based in part on the 2011 International Coeliac Disease Symposium, concluded that the use of this term should be avoided due to a lack of specificity. Gluten is a group of proteins, such as prolamins and glutelins, stored with starch in the endosperm of various cereal (grass) grains. , gluten-related disorders were increasing in frequency in different geographic areas. The increase might be explained by the popularity of the Western diet, the expanded reach of the Mediterranean diet (which also includes grains with gluten), the growing replacement of rice by wheat in many countries, the development in recent years of new types of wheat with a higher amoun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gluten
Gluten is a structural protein naturally found in certain cereal grains. Although "gluten" often only refers to wheat proteins, in medical literature it refers to the combination of prolamin and glutelin proteins naturally occurring in all grains that have been proved capable of triggering celiac disease. These include any species of wheat (such as common wheat, durum, spelt, khorasan, emmer and einkorn), barley, rye and some oat cultivars, as well as any cross hybrids of these grains (such as triticale). Gluten makes up 75–85% of the total protein in bread wheat. Glutens, especially Triticeae glutens, have unique viscoelastic and adhesive properties, which give dough its elasticity, helping it rise and keep its shape and often leaving the final product with a chewy texture. These properties, and its relatively low cost, make gluten valuable to both food and non-food industries. Wheat gluten is composed of mainly two types of proteins: the glutenins and the gliadins, which i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Egg White
Egg white is the clear liquid (also called the albumen or the glair/glaire) contained within an egg. In chickens it is formed from the layers of secretions of the anterior section of the hen's oviduct during the passage of the egg. It forms around fertilized or unfertilized egg yolks. The primary natural purpose of egg white is to protect the yolk and provide additional nutrition for the growth of the embryo (when fertilized). Egg white consists primarily of about 90% water into which about 10% proteins (including albumins, mucoproteins, and globulins) are dissolved. Unlike the yolk, which is high in lipids (fats), egg white contains almost no fat, and carbohydrate content is less than 1%. Egg whites contain about 56% of the protein in the egg. Egg white has many uses in food (e.g. meringue, mousse) as well as many other uses (e.g. in the preparation of vaccines such as those for influenza). Composition Egg white makes up around two-thirds of a chicken egg by weight. Water co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gelatin
Gelatin or gelatine (from la, gelatus meaning "stiff" or "frozen") is a translucent, colorless, flavorless food ingredient, commonly derived from collagen taken from animal body parts. It is brittle when dry and rubbery when moist. It may also be referred to as hydrolyzed collagen, collagen hydrolysate, gelatine hydrolysate, hydrolyzed gelatine, and collagen peptides after it has undergone hydrolysis. It is commonly used as a gelling agent in food, beverages, medications, drug or vitamin capsules, photographic films, papers, and cosmetics. Substances containing gelatin or functioning in a similar way are called gelatinous substances. Gelatin is an irreversibly hydrolyzed form of collagen, wherein the hydrolysis reduces protein fibrils into smaller peptides; depending on the physical and chemical methods of denaturation, the molecular weight of the peptides falls within a broad range. Gelatin is present in gelatin desserts, most gummy candy and marshmallows, ice creams, dips ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fining Agent
Finings are substances that are usually added at or near the completion of the processing of brewing wine, beer, and various nonalcoholic juice beverages. They are used to remove organic compounds, either to improve clarity or adjust flavor or aroma. The removed compounds may be sulfides, proteins, polyphenols, benzenoids, or copper ions. Unless they form a stable sediment in the final container, the spent finings are usually discarded from the beverage along with the target compounds that they capture. The term “finings” is a mass noun rather than a plural. Substances used as finings include egg whites, blood, milk, isinglass, and Irish moss. These are still used by some producers, but more modern substances have also been introduced and are more widely used, including bentonite, gelatin, casein, carrageenan, alginate, diatomaceous earth, pectinase, pectolyase, PVPP, kieselsol ( colloidal silica), copper sulfate, dried albumen (egg whites), hydrated yeast, and activa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clarification And Stabilization Of Wine
In winemaking, clarification and stabilization are the processes by which insoluble matter suspended in the wine is removed before bottling. This matter may include dead yeast cells ( lees), bacteria, tartrates, proteins, pectins, various tannins and other phenolic compounds, as well as pieces of grape skin, pulp, stems and gums.J. Robinson (ed) ''"The Oxford Companion to Wine"'' Third Edition, pp. 173, 661–62. Oxford University Press 2006 . Clarification and stabilization may involve fining, filtration, centrifugation, flotation, refrigeration, pasteurization, and/or barrel maturation and racking. Clarifying wine In wine tasting, a wine is considered " clear" when there are no visible particles suspended in the liquid and, especially in the case of white wines, when there is some degree of transparency. A wine with too much suspended matter will appear cloudy and dull, even if its aroma and flavor are unaffected; wines therefore generally undergo some kind of clarificati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungus
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from the other eukaryotic kingdoms, which by one traditional classification include Plantae, Animalia, Protozoa, and Chromista. A characteristic that places fungi in a different kingdom from plants, bacteria, and some protists is chitin in their cell walls. Fungi, like animals, are heterotrophs; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesize. Growth is their means of mobility, except for spores (a few of which are flagellated), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. These and other differences place fungi in a single group of related organisms, named the ''Eumycota'' (''true f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thaumatin
Thaumatin (also known as talin) is a low-calorie sweetener and flavor modifier. The protein is often used primarily for its flavor-modifying properties and not exclusively as a sweetener. The thaumatins were first found as a mixture of proteins isolated from the katemfe fruit (''Thaumatococcus daniellii'') (Marantaceae) of West Africa. Although very sweet, thaumatin's taste is markedly different from sugar's. The sweetness of thaumatin builds very slowly. Perception lasts a long time, leaving a liquorice-like aftertaste at high concentrations. Thaumatin is highly water soluble, stable to heating, and stable under acidic conditions. Biological role Thaumatin production is induced in katemfe in response to an attack upon the plant by viroid pathogens. Several members of the thaumatin protein family display significant ''in vitro'' inhibition of hyphal growth and sporulation by various fungi. The thaumatin protein is considered a prototype for a pathogen-response protein do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
