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Lactose Permease
Lactose is a disaccharide composed of galactose and glucose and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from ( gen. ), the Latin word for milk, plus the suffix '' -ose'' used to name sugars. The compound is a white, water-soluble, non-hygroscopic solid with a mildly sweet taste. It is used in the food industry. Structure and reactions Lactose is a disaccharide composed of galactose and glucose, which form a β-1→4 glycosidic linkage. Its systematic name is β-D-galactopyranosyl-(1→4)-D-glucose. The glucose can be in either the α-pyranose form or the β-pyranose form, whereas the galactose can have only the β-pyranose form: hence α-lactose and β-lactose refer to the anomeric form of the glucopyranose ring alone. Detection reactions for lactose are the Wöhlk and Fearon tests. They can be used to detect the different lactose content of dairy products such as whole milk, lactose free milk, yogurt, butter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethanol
Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the pseudoelement symbol for ethyl group, ethyl. Ethanol is a Volatility (chemistry), volatile, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. As a psychoactive depressant, it is the active ingredient in alcoholic beverages, and the second most consumed drug globally behind caffeine. Ethanol is naturally produced by the fermentation process of sugars by yeasts or via petrochemical processes such as ethylene hydration. Historically it was used as a general anesthetic, and has modern medical applications as an antiseptic, disinfectant, solvent for some medications, and antidote for methanol poisoning and ethylene glycol poisoning. It is used as a chemical solvent and in the Chemical synthesis, synthesis of orga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfred Wöhlk
Alfred Wöhlk, also: Woehlk, Wøhlk, (1868–1949) was a Danish chemist and pharmacist. With his historical detection reaction from 1904, the lactose content of dairy products can be visualized. This is useful because many people are lactose intolerant and avoid dairy products. Countless pharmacy students, but also physicians, laboratory assistants, and recently also chemistry teachers know the Wöhlk test. Since its discovery in 1904 until the 1960s, the Wöhlk test has mainly been used to detect the reducing disaccharide lactose in urine in medical laboratories. Although there were already a number of wet-chemical detection methods to identify sugars, such as the Fehling or Benedict test, those analyses could only differentiate between reducing and non-reducing sugars. Since both glucose and lactose molecules have an aldehyde group in the open-chain form, the result was positive in both cases. Only the Woehlk test allowed a safe differentiation between glucose and lactose. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basicity
In chemistry, there are three definitions in common use of the word "base": ''Arrhenius bases'', ''Brønsted bases'', and ''Lewis bases''. All definitions agree that bases are substances that react with acids, as originally proposed by Guillaume-François Rouelle, G.-F. Rouelle in the mid-18th century. In 1884, Svante Arrhenius proposed that a base is a substance which dissociates in aqueous solution to form hydroxide ions OH−. These ions can react with Hydron (chemistry), hydrogen ions (H+ according to Arrhenius) from the dissociation of acids to form water in an acid–base reaction. A base was therefore a metal hydroxide such as NaOH or Calcium hydroxide, Ca(OH)2. Such aqueous hydroxide solutions were also described by certain characteristic properties. They are slippery to the touch, can taste Taste#Bitterness, bitter and change the color of pH indicators (e.g., turn red litmus paper blue). In water, by altering the self-ionization of water, autoionization Chemical equi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isomerisation
In chemistry, isomerization or isomerisation is the process in which a molecule, polyatomic ion or molecular fragment is transformed into an isomer with a different chemical structure. Enolization is an example of isomerization, as is tautomerization. When the activation energy for the isomerization reaction is sufficiently small, both isomers can often be observed and the equilibrium ratio will shift in a temperature-dependent equilibrium with each other. Many values of the standard free energy difference, \Delta G^\circ, have been calculated, with good agreement between observed and calculated data. Examples and applications Alkanes Skeletal isomerization occurs in the cracking process, used in the petrochemical industry to convert straight chain alkanes to isoparaffins as exemplified in the conversion of normal octane to 2,5-dimethylhexane (an "isoparaffin"): : Fuels containing branched hydrocarbons are favored for internal combustion engines for their higher octane r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrolysed
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis is the cleavage of biomolecules where a water molecule is consumed to effect the separation of a larger molecule into component parts. When a carbohydrate is broken into its component sugar molecules by hydrolysis (e.g., sucrose being broken down into glucose and fructose), this is recognized as saccharification. Hydrolysis reactions can be the reverse of a condensation reaction in which two molecules join into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water. Types Usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both the substance and water molecule to split into two parts. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemistry Teacher International
''Chemistry Teacher International'' is a quarterly open-access peer-reviewed chemistry journal published by De Gruyter. The editor-in-chief is Mustafa Sözbilir ( Atatürk University). It was established in 2019 by the International Union of Pure and Applied Chemistry Committee on Chemistry Education, following the identification of a distinct lack of published papers on good practices in chemistry education by Marcy Towns and Adam Craft in 2012 and Keith Taber in 2016. The founding editor-in-chief was Jan Apotheker (University of Groningen). The journal covers good practices in secondary education, especially those that would normally be published in national teacher journals and not international publications. Abstracting and indexing The journal is abstracted and indexed in: *Directory of Open Access Journals * EBSCO databases *Emerging Sources Citation Index *Scopus According to the ''Journal Citation Reports'', the journal has a 2022 impact factor The impact factor (IF) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kefir
Kefir ( ; alternative spellings: kephir or kefier; ; ; ) is a Fermented milk products, fermented milk drink similar to a thin yogurt or ayran that is made from kefir grains, a specific type of mesophilic SCOBY, symbiotic culture. It is prepared by inoculation, inoculating the milk of Milk#Sources, cows, goat milk, goats, or sheep milk, sheep with kefir grains. Kefir is a common breakfast, lunch or dinner drink consumed in countries of western Eurasia. Kefir is consumed at any time of the day, such as alongside European pastries like zelnik (zeljanica), Börek, burek and banitsa/gibanica, as well as being an ingredient in cold soups. Origin and etymology Kefir has been found in graves in the Bronze Age Xiaohe Cemetery, dating back 3,600 years. The word ''kefir'', which is of North Caucasian origin, became an Internationalism (linguistics), international word, having originally spread to Russia, Central European and Eastern European countries at least by 1884, A Russian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sour Cream
Sour cream (sometimes known as soured cream in British English) is a dairy product obtained by fermenting regular cream with certain kinds of lactic acid bacteria. The bacterial culture, which is introduced either deliberately or naturally, sours and thickens the cream. Its name comes from the production of lactic acid by bacterial fermentation, which is called souring. Crème fraîche is one type of sour cream with a high fat content and less sour taste. Traditional Traditionally, sour cream was made by letting cream that was skimmed off the top of milk ferment at a moderate temperature. It can also be prepared by the souring of pasteurized cream with acid-producing bacterial culture. The bacteria that developed during fermentation thickened the cream and made it more acidic, a natural way of preserving it. Commercial varieties According to US ( FDA) regulations, commercially produced sour cream contains no less than 18% milkfat before bulking agents are added, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coffee Creamer
A non-dairy creamer, commonly also called tea whitener or coffee whitener or else just creamer, is a liquid or granular product intended to substitute for milk or cream as an additive to coffee, tea, hot chocolate, or other beverages. Most do not contain lactose and therefore are commonly described as being non-dairy products, although many contain casein, a milk-derived protein. Dry granular products do not need to be refrigerated and can be used and stored in locations which do not have a refrigerator. Liquid non-dairy creamers should be tightly capped and refrigerated after opening. Some non-dairy creamers contain sweeteners and flavors, such as vanilla, hazelnut, or Irish cream. As with other processed food products, low-calorie and low-fat versions are available for non-dairy creamers. History Holton "Rex" Diamond, an employee of Rich Products, performed experiments from 1943 to 1945 using a form of soybean protein" to make a "soy cream" that would not form curds when m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buttermilk
Buttermilk is a fermented dairy drink. Traditionally, it was the liquid left behind after churning butter out of cultured cream. As most modern butter in Western countries is not made with cultured cream but uncultured sweet cream, most modern buttermilk in Western countries is cultured separately. It is common in warm climates, where unrefrigerated milk sours quickly. Buttermilk can be drunk straight, and it can also be used in cooking. In making soda bread, the acid in buttermilk reacts with the raising agent, sodium bicarbonate, to produce carbon dioxide which acts as the leavening agent. Buttermilk is also used in marination, especially of chicken and pork. Traditional buttermilk Originally, buttermilk referred to the thin liquid left over from churning butter from cultured or fermented cream. Traditionally, before the advent of homogenization, the milk was left to sit for a period of time to allow the cream and milk to separate. During this time, naturally occurr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yogurt
Yogurt (; , from , ; also spelled yoghurt, yogourt or yoghourt) is a food produced by bacterial Fermentation (food), fermentation of milk. Fermentation of sugars in the milk by these bacteria produces lactic acid, which acts on milk protein to give yogurt its texture (food), texture and characteristic tart flavor. Cow's milk is most commonly used to make yogurt. Milk from water buffalo, goats, sheep, ewes, mares, camels, and yaks is also used to produce yogurt. The milk used may be Milk#Creaming and homogenization, homogenized or not. It may be pasteurized or raw milk, raw. Each type of milk produces substantially different results. Yogurt is produced using a culture of Lactobacillus delbrueckii subsp. bulgaricus, ''Lactobacillus delbrueckii'' subsp. ''bulgaricus'' and ''Streptococcus thermophilus'' bacteria. Other Lactobacillus, lactobacilli and Bifidobacterium, bifidobacteria are sometimes added during or after culturing yogurt. Some countries require yogurt to contain a spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lactose Free Diet
Lactose intolerance is caused by a lessened ability or a complete inability to digest lactose, a sugar found in dairy products. Humans vary in the amount of lactose they can tolerate before symptoms develop. Symptoms may include abdominal pain, bloating, diarrhea, flatulence, and nausea. These symptoms typically start thirty minutes to two hours after eating or drinking something containing lactose, with the severity typically depending on the amount consumed. Lactose intolerance does not cause damage to the gastrointestinal tract. Lactose intolerance is due to the lack of the enzyme lactase in the small intestines to break lactose down into glucose and galactose. There are four types: primary, secondary, developmental, and congenital. Primary lactose intolerance occurs as the amount of lactase declines as people grow up. Secondary lactose intolerance is due to injury to the small intestine. Such injury could be the result of infection, celiac disease, inflammatory bowel disea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
