The Process and Quality Factors of Making Alkaline Noodles

Alkaline noodles, known for their distinctive texture and flavor, share a similar basic procedure with white salted noodles. This essay details a lab-scale method for producing alkaline noodles and explores the factors influencing their eating quality.

The process begins with the preparation of ingredients. For a batch, 300 grams of flour, 96 milliliters of water, 2.7 grams of sodium carbonate (Na2CO3), and 0.3 grams of potassium carbonate (K2CO3) are combined. These ingredients are mixed in a mixer for one minute at a slow speed, followed by one minute at a fast speed, and then an additional three minutes at a slow speed. This creates a crumbly dough, which is then sheeted between steel rollers set 2.75 millimeters apart using an Ohtake noodle machine.

Next, the dough sheet is folded and passed through the rollers twice more, then allowed to rest for 30 minutes in a plastic bag. This resting period is crucial for the dough's relaxation and hydration. The dough is then gradually thinned by passing it through the rollers with decreasing clearance settings of 2.5, 2.0, and finally 1.5 millimeters. After resting for three hours at 25°C, the noodles are boiled until the uncooked core disappears, usually around five minutes. The cooked noodles are then subjected to sensory testing to evaluate their quality.

The principal factors governing the eating quality of yellow alkaline noodles are protein content, dough strength, and starch paste viscosity. Alkaline noodles use hard wheat, whose low-swelling starches are further restricted from swelling by the carbonate salts. This results in hard, elastic starch gels. The high protein content and small voids in the dough contribute to the chewy texture of the noodles.

Alkaline salts significantly alter the pH and color of the noodles. The high pH environment enhances water absorption properties, resulting in a chewier texture with less tendency to soften and paste after cooking. The distinctive flavor of alkaline noodles, characterized by an alkaline odor, is a critical factor in consumer acceptance. The yellow color of the noodles is due to naturally occurring flavones in the flour, which turn yellow at high pH levels. The hue and intensity of this yellow color are influenced by the type of alkaline salt used, the duration after sheeting, protein content, and the degree of flour refinement.

High-quality alkaline noodles require highly refined flour to maximize brightness and minimize visible bran specks. The refinement process removes impurities that can affect the noodles' appearance and texture.

In recent developments, advances in flour refinement technology and ingredient processing have led to more consistent quality in alkaline noodles. Innovations in noodle-making machines also allow for better control over dough thickness and texture, enhancing the overall eating experience. Furthermore, understanding consumer preferences has led to formulations that balance traditional qualities with modern taste expectations.

In conclusion, making alkaline noodles involves a meticulous process and attention to key factors like protein content, dough strength, and starch viscosity. The addition of alkaline salts not only affects the noodles' pH and color but also enhances their texture and flavor. With advancements in technology and ingredient processing, the quality and consistency of alkaline noodles continue to improve, meeting the evolving demands of consumers.
The Process and Quality Factors of Making Alkaline Noodles

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Spray drying instant coffee

Spray drying instant coffee refer to a type of coffee that has been treated with a spray drying process that remove all the water from the coffee beans.

Spray dryers are rapid dryer, drying rate is high. Product quality can be controlled and maintained in drying process. Highly controllable drying systems flow of hot air, droplet speed and droplet temperature can be effectively controlled.

With spray-dried coffee, the texture of the coffee powder is usually very fine for most people. Coffee aroma consists of a complex mixture of volatile compounds, whereas non-volatile compounds contribute to flavors such as sourness, bitterness, and astringency.

Spray drying is achieved by spraying liquid coffee concentrate as a fine mist into very hot, dry air. The droplets are dried in very hot air (approx. from 80 to 180˚C) and evaporate leaving behind the coffee powder.

The spray drying process is very quick and uses high heat. Because of that, the process produces fine and small particles, which results as a powdered form.
Spray drying instant coffee

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Food homogenization

Homogenization is an essential unit operation during the manufacture of a number of food and dairy products. Homogenization involves coaxing two otherwise immiscible liquids into mixing to create a new, often creamy, liquid. The main result of homogenization is a stable emulsion – meaning the size of the droplets doesn’t change significantly with time.

Homogenization is an ideal method for producing emulsions, suspensions, and other products that require a liquid suspended in another liquid (e.g. water-in-oil or oil-in-water), or which require a small particle size. Homogenized and/or fortified food products benefit from improved aesthetic properties — including enhanced appearance, flavor and/or “mouth feel,” as well as better nutritional profiles and enhanced shelf stability.

Cream and other food products, such as peanut butter, may be homogenized to produce a stable emulsion—one in which fats or oils will not separate from other elements.

Homogenization is a common step in the modern-day processing of milk. Fortified milk, for example, consists of homogenized milk containing dissolved solutes, such as proteins and minerals; and lipids in the form of milk fat. Milk homogenization is a simple process that mixes and disperses that milkfat by using a high-pressure procedure to break it down into smaller particles. When finished, the tiny particles stay suspended in the milk to create a more uniform mixture. Homogenization gives milk its rich, white color and smooth texture.

The intensive pressure applied by a high-pressure homogenizer causes most foods to attain more stable chemical structures; this allows for a longer period of freshness than would otherwise be possible, especially compared with foods comprised of larger particles.
Food homogenization

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HTST pasteurization system

Milk and dairy products are an important source of nutrients. They are considered as the main food products in the human diet.

Milk should be free from toxins and pathogens and also it must retain all nutrients and vitamins with extended period of storage life. To achieve the above said criteria, milk is heated to a particular temperature for a brief time then cooling it down once more quickly. Pasteurization is the process of heating the product to a predetermined temperature and holding it until all or nearly all objectionable microorganisms, which may be present, are killed.

HTST (High temperature short time) pasteurization is an effective method of making milk safe for consumption, without unduly changing either its sensory characteristics or its nutritional value. As a continuous process, it makes use of energy regeneration and it is capable of both scales of operation and energy efficiencies that cannot be matched by alternative processes.

This method involves heating milk rapidly to 72◦C, keeping it for a few seconds (usually 15 s), and cooling it down immediately. The time and temperature conditions depend on several factors, such as size, shape, and type of food. The HTST method results in a higher retention of quality characteristics.

For HTST pasteurization, the following controls are very important:
• Flow rate
• Temperature
• Pressure
HTST pasteurization system

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Sea salt: Made by evaporating seawater

Salt is a mineral that is mainly composed of sodium chloride. Most sea salts and table salt contain about 40 percent sodium by weight. It is an essential part of the diet without which food becomes tasteless. It is required for both plants and animals in small quantities, but harmful when present in excess.

Salt for human consumption is produced in different forms: salt evaporated as well as cold refined, rock salt, sea salt (refined and unrefined), dendritic (contains ferrocyanide salts), fluoridated salt, and salt fortified with iron. Refined salt usually contains about 99.5–99.9% NaCl and some additives such as whitening and anti-caking agents to keep the salt crystals from sticking together as they absorb moisture from the air.

Salt is extracted from oceans and saline lakes (e.g. Great Salt Lake, Dead Sea, Caspian Sea, Issak Kul in Kyrgyzstan, Lake Eyre in Australia and Chilwa in Malawi), through evaporation of water to leave salt crystals that can then be harvested mechanically. Any impurities that are present in the brine are drained off and discarded prior to harvesting.

Salts are crystallized through a series of heating and cooling steps and then harvested using centrifugation. The physical changes that result in crystallization are the result of ionic bonds rather than covalent bonds.

Sea salt consists of about 98% NaCl with remaining 2% is constituted by trace elements like iron, magnesium, sulfur and iodine.

Sea salt has boomed in popularity in restaurants and supermarket aisles. Many gourmet chefs say they prefer it over table salt for its coarse, crunchy texture and stronger flavor. Manufacturers are using it in potato chips and other snacks because it’s “all natural,” and less processed than table salt.

The air near sea water contains salt particles that control the radioactive properties of clean background atmosphere by scattering sunlight. Sea salt is also used in cosmetics and as bathing salt, but takes high concentration of iodine, an essential element for human health.

Because of industrialization, it is usually blamed that due to pollution load it may receive various industrial effluents which are rich sources of heavy metals with negative impact on health like cadmium, nickel, zinc, molybdenum and iron.
Sea salt: Made by evaporating seawater

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Soybean oil

Vegetable soybean, is an herbaceous plant from the Fabaceae family (legume) naturally originated in southeastern Asia (Japan, Korea, and China) that was domesticated 3.000 years ago because of its young pods and edible seeds. Their early introduction to the U.S. can be traced back to the mid-eighteenth century, with the largest official introduction occurring in the early 1900s.

Soybeans have high amount of protein and oil, and they are used into diverse food products. Modern soy oil is a stable high quality triglyceride ingredient used widely in commercial processed foods.

It is the major edible oil in use in the United States and is a labeled ingredient of premium food products.

Soy oil is used in cooking, such as margarine, shortening, salad oil as well as in industrial products (paints, printing inks, disinfectants, biofuel, and linoleum).

Soybean oil is a complex mixture of five fatty acids (palmitic, stearic, oleic, linoleic, and linolenic acids) that have vastly differing melting points, oxidative stabilities, and chemical functionalities.

The concentration of soybean oil ranges from 83 g/kg to 279 g/kg. Soybean oil contains a high amount of unsaturated acids important in the human nutrition: α-linolenic acid (omega-3 acid), linoleic, γ-linolenic and arachidonic acid (omega-6 acid), and oleic acid known as omega-9.

The proportion of linoleic acid of soybean oil ranged from 49% to 53.5% and the palmitic acid of oils varied between 9.2% and 11.2%. The major sources of tocopherols were γ-tocopherol, α-tocopherol, and δ-tocopherol in all varieties of soybean oil.

Modern soybean processing starts with solvent extraction to obtain crude oil and defatted meal. For hexane extraction, the solubility of oil and hexane is the basic principal, and it can have over 99% of oil recovery rate.

The oil in water emulsion is formed after the extraction process due to the insolubility of water and oil, and the demulsification is applied to recover the oil from the emulsion.

Crude oil contains variable amounts of non-triglyceride materials. To remove some of these impurities from the crude soy oil and convert it to a high-quality edible oil, it is necessary to subject crude oil to a series of refining operations, including degumming to remove lecithin, neutralization to separate out free fatty acids and bleaching to remove pigments and the residues of previous refining steps. Oil refining is usually a continuous process.

Deodorization is the last process step used to improve the taste, odor, color, and stability of the oil by removal of undesirable substances. All commercial deodorization, whether in continuous, semi-continuous, or batch units. is essentially a steam-stripping of the oil for removal of free fatty acids and other volatile materials.

The final product is a refined, bleached, and deodorized oil, commonly known as RBD oil.
Soybean oil

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Food preservation: The smoking process

Smoking is an ancient method of food preservation, which is also known as smoke curing, produces products with very high salt content (more than 10%) and low water activity (~0.85). While smoking process, some reactions occur between food and smoke Smoking operation which adds some volatile compounds to the product inhibits bacterial growth and gives a specific taste to the product.

Smoking is the process of flavoring, cooking, or preserving food by exposing it to smoke from burning or smoldering material, most often wood. It is an ancient method of preserving food using wood smoke. It is believed to be almost as old as the use of fire itself.

This process is usually characterized by an integrated combination of salting, drying, heating and smoking steps in a smoking chamber. The drying effects during smoking, together with the antioxidant and bacteriostatic effects of the smoke, allow smoked products to have extended shelf-life.

Smoking is still widely used in fish and meat and some other foods. The smoking process allows cured meats, poultry, game and seafood to be subjected to smoke in a controlled environment. The smoke is produced by smoldering hardwood chips, vines, herbs, fruit skins, or spices.

Different species of fish require different preparation techniques. Salmon are usually prepared by removing the backbone and splitting. Bottom fish are filleted. Small fish such as herring and smelt should be headed and gutted before brining.

Smoke is generated from the incomplete combustion of wood at certain temperatures followed by thermal disintegration or pyrolysis of high molecular organic compounds into volatile lower molecular mass (. Smoke is composed of two phases: a particulate or dispersed phase and a gaseous or dispersing phase. The major parts of dispersed phase are particles in the droplet form having an average diameter of 0.196 to 0.346 µm.

While smoking process, some reactions occur between food and smoke. After smoking process, a second covering shell occurs in food or meat products. Smoking operation which adds some volatile compounds to the product inhibits bacterial growth and gives a specific taste to the product. This smoke influences the flavor, aroma, texture, appearance and shelf life of foods. The process can be performed at temperatures that range generally from 65°F to 250°F.

Food smoking is part of a revival of old crafts and traditional foods, and an increase in food awareness – people want to know what's in the food they are eating. The trend is towards high-quality ‘slow’ food, with local, natural ingredients free from chemical additives. Smoking is a way for farmers, smallholders, hunters and fishermen to make use of large amounts of meat or fish at certain times of the year.
Food preservation: The smoking process

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Grain processing: Kilning process

Malting is a three-step process consisting of steeping, germination and finally kilning. When germination stage is deemed to have lasted long enough, it is stopped by heating the grain in a process referred to as kilning.

The aim is to drive off water until the moisture level in grain is below 5%, when the metabolism of the barley will be heated and the product stabilized. The objective is to achieve development of malt colors and flavors.

This requires intense heat, yet the malt enzymes, which heat tends to inactivate, must be conserved The kiln has provision of gradual temperature increase and air circulation, and energy is conserved to the maximum extent possible.

The kilning is usually done from 16-40 h with gradual increase in the temperature. In the kilning process, the breakdown products (amino acids and sugars) released from proteins and carbohydrates during germination meld to form so-called melanoidins, which are colored.
Grain processing: Kilning process

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Extrusion processing technology of cereal

Extrusion processing is widespread throughout the food industry because it is a continuous operation, is very flexible in its range of application, and gives end products of reproducible quality.

A wide range of extruder conditions may be used to produce pasta, cereals snack or breakfast cereals. These are typically made from cereal grains such as corn, wheat rice and oats.

Ingredients such as water, oil and emulsifiers may be added to modify product characteristics. During extrusion, chemical constituents of the feed material are exposed to high temperature, high shear and/or high pressure that may improve or damage the nutritional quality of proteins in the extruded materials by various mechanisms.

These changes depend on temperature, moisture, pH, shear rate, residence time and their interaction, the nature of the proteins themselves and presence of materials such as carbohydrates and lipids.

Several studies showed that extrusion processing under certain conditions could enhance the cholesterol-lowering activity of some cereal.

Within the extruder, the cereal grain is mixed, cooked, melted and forced through a die under pressure to form the final product. Operating parameter that can be varied to control the density and texture of the final product include moisture, feed rate, barrel temperature and screw speed.
Extrusion processing technology of cereal

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Solvent extraction for cocoa butter

Cocoa butter is composed mainly of glycerides of stearic, palmitic and oleic fatty acids. It is a unique fat with specific melting characteristics.

The solvent extraction of cocoa butter has been developed and perfected over many years.  There are many types of solvent-extraction equipment, batch and continuous, with modifications to suit the materials being treated, whether seeds, nut residues, offal or bones.

With cocoa, material for extraction is preferably in the form of corns from expeller presses or cubes, as powder does not really allow percolation of the solvent.

Solvent extraction removes certain gums and phosphatides as well as the fat, but extracted fats are usually subjected to deodorization and degumming processes so that these cocoa butters have a bland flavor. They also have the reputation of being softer and with less ‘snap’ than expressed butters.

Despite the favorable characteristics of flavor, solvent extracted butter normally only forms 2-5% of the butter blend for chocolate as it is softer than that produced by conventional pressed liquor.

The flavor of cocoa butter is determined by both the geographical origin of the beans and the deodorization condition. Deodorization reduces the levels of free fatty acids but also antioxidant compounds such as tocopherols.
Solvent extraction for cocoa butter

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Tea cream: definition and processing of tea.

On cooling, a tea solution becomes opaque and lightens in color. This is due to the formation of tea cream, a colloidal substance which contains the same components as the original extract.

Chemically, tea cream is the complex of theaflavins, TF-gallate, EGCG, ECG, TRs, caffeine, caffeic, acid, gallic acid, ellagic acid, chlorophyll, and bisflavanol A, B.

The conditions under which cream forms determined the chemical composition of the complex and its physical properties. The cream properties are accepted as one of the quality attributes of black tea infusion. The amount of tea cream is a measure of the strength and briskness of black tea.

Cream processing can be accomplished by maintaining the temperature above 65 °C or by removal of the cream, for example by cooling followed by precipitation or centrifugation.

Since tea cream contains many flavor compounds removal by precipitation decreases the quality of the tea and incidentally decreases the yield of solids from the leaf, so solubilization by maintaining the temperature is a preferred method.

Cream treatment is especially necessary for cold water-soluble instants, which are commonly used for beverages like ice tea.

Tea cream causes particular problems in production of instant tea for the US market, which is required to be of clear, bright appearance when reconstituted with cold water.
Tea cream: definition and processing of tea

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Saké rice wine fermentation

Saké , a Japanese traditional alcohol beverage is produced by saccharification of rice starch by koji and alcoholic fermentation. Sake making has developed into a modern fermentation industry, producing clear, pale-colored rice wine with alcoholic content of 1% - 16% or higher. It has characteristics flavor and aroma, small amount of acid and slight sweetness.

Raw materials for saké: water used for saké should be colorless, tasteless and odorless, neutral or weakly alkaline, and substantially free of iron, nitrate, ammonia, organic substance and harmful organisms.

Rice of the short-grained varieties is considered best for saké manufacture and large grains are considered desirable.

The characteristics features in saké brewing are the use of ‘koji’ a culture of Aspergillus oryzae grown on and within steamed rice grains and parallel fermentation by saké yeast.

The first step is the preparation of milled rice and its steaming. This followed by the preparation of koji and the preparation of moto mash, starter for saké yeast prepared by mashing steamed rice, koji and water. The moto bubbles for a few days in a warm environment.

Koji and water are added in the evening, then the next morning more rice is added. Once all the rice has been incorporated, the rice mash is known as moromi.

The main fermentation takes 20-25 day. When fermentation has ceased the moromi mash is filtered to remove the solids; the filtrate thus obtained is fresh saké. After about a month, the fresh saké is pasteurized and stored.
Saké rice wine fermentation

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Evaporation processing

Concentration of liquid foods is an important operation of many food processes and there are several technologies available, such as evaporation under vacuum and membrane concentration.

Evaporation has historically been the primary technology for liquid concentration in the food industry.

Evaporation removes most of the water resulting in concentrated product which may be used as such or processed further, e.g. by drying.

Evaporation is employed in the food industry to reduce weight and volume of fluids, with subsequent reduction of packaging, transportation, and storage costs. It also used to reduce the energy consumption at the drying operation.

Another important application is the production of fruit (mainly grape, apple, and orange) and vegetable (mainly tomato products) juice concentration.

In the dairy industry, evaporation is used for concentration duties, such as milk, skimmed milk and whey. It is also used as a preliminary step to drying. The thermal efficiency of evaporators for removing water us much higher (e.g 90%), compared to the efficiency of dryers (e.g. 60%).

Evaporation of water from the solution by heating is feasible, but usually the products to be evaporated are heat sensitive and heating can change some their physicochemical characteristics at this elevated temperature. Evaporation might result in crustal precipitation.

Evaporation might also result in foaming of the concentrate. Evaporation at low temperatures, under vacuum, reduces thermal degradation of food properties (textural and nutritional) and aroma recovery schemes allow collection of essential flavors and aroma compounds.
Evaporation processing

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Spray drying of milk

Dry milk was referred to as milk powder until the mid 1960s, when the designation was changed by the American Dry Milk Institute to dry milk in the United States.

Drying be done by spraying atomized droplets of milk into chamber through which heated air is circulated (spray drying).

Milk to be spray dried should receive at least a minimum temperature pasteurization before evaporation and further processing, though higher temperature heat treatments are commonly used in order to influence product characteristics.

In the more modern and more widely used process, concentrated milk is sprayed through an atomizer into the top of a large chamber with air at 120 – 205 °C blown in from the base. The particles dry rapidly and are collected at the bottom of the chamber.

Dried milk (usually the spray dried type that contains about 5% of moisture) may be re-humidified to slightly higher moisture content after drying.

This treatment agglomerates the fine milk particles  to form clumps of milk powder, which results in a powder that dissolves or disperses in water much more rapidly that the finely powdered dried milk. It is therefore, considered to be an instantly double product.

Original spray dryer designs were for single stage drying in which all of the moisture is removed in the main drying chamber. Such designs are now obsolescent and have been replaced by two and three stage dryers in which the drying process is completed in fluidized bed dryers.
Spray drying of milk

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Primary objective of food processing

The composition and moisture content of food creates an ideal environment for the growth and proliferation of pathogenic and spoilage microorganisms.

Processing operations involves not just involves just a minor change of form, from dirty to clean but it also involves processing to assure safety, to drastically alter the form of the raw materials, and to provide a product that will remain stable for many months on the shelf.

It must be acknowledge that most if not all food processing operations will influence the physical and sensory characteristics of the product.

Modern food processing preserves food quality, controls food spoilage and disease causing microorganisms, preserves desirable sensory qualities such as flavor, odor, texture, and appearance, preserves nutrients content and in many cases enhances the nutrient value as well.

Processing to retard spoilage permits foods to be consumed at a later date and frequently at a distance from the point of production.
Primary objective of food processing

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Impact of food processing and storage to fat-soluble vitamins

The most significant losses of vitamins occur in raw materials during storage and as a consequence of handling, food processing and extending the shelf-life of nutritive foodstuffs.

The chemical properties of vitamins dictate the mechanism and extent of losses during processing. Fat soluble vitamins are degraded by a distinctly different set of chemical processes than water soluble vitamins.

In generally fat-soluble vitamin can be affected by physical factors (temperature, sunlight and UV light radiation, oxygen/air) chemical factors (radicals, peroxides, metal ions, Cu2+, Fe3+) and the biochemical factors (enzymes, mainly oxidases, eg.g lipoxygenase).

Fat–soluble vitamins are particularly susceptible to oxidation due to all of these factors and the process is further accelerated by the presence of oxidized fat. The fat-soluble vitamins, particularly A, D and E are sensitive to oxidation during processing and storage. The fat soluble vitamins and vitamin processes (carotenoids and tocotrienes) are destroyed by autocatalytic processes similar to these experienced by unsaturated fatty acids.

The fat-soluble vitamins are generally less heat-labile than the water soluble ones, but they are susceptible to degradation at high temperature especially in the presence of oxygen.

Certain fat-soluble (particularly vitamin A and the carotenoids) experience geometric isomerization upon thermal processing with losses of vitamin value. All the fat-soluble vitamins are lost at a varying degree during thermal processing with the exception of vitamin K.

Vitamin A has little loss during cooking but presence of acid it becomes rancid. No loss during canning and processing.
Impact of food processing and storage to fat soluble vitamins

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Extraction process of instant tea

The basic steps in the preparation of instant teas are extraction of tea solids from fermented but unfired tea leaf, black tea, or green tea, followed by concentration of the extract and drying of the concentrate to a powder.

Instant tea processing begins with extraction of the selected tea leaf blend. Generally a fermented black tea type is used – one chosen for reddish color, relative freedom form haze and strong flavor when brewed. The extraction process is one with heated water in a static system consisting of three to five cells.

Modern extraction systems are based ion counter-current flow and either batch or continuous systems may be used.  About ten parts of water are combined with one part of tea leaves by weight in the extractors and extraction is carried out at temperatures between about 60 ° C and 100 °C for 10 minutes.

Concentration of the extract is effected by evaporation of the water under reduced pressure at a moderately elevated temperature and during this process various methods for trapping the escaping volatile compounds have been devised. These trapped volatiles are concentrated and retained for incorporation into the final dried product.

The yield of solids during extraction frequently ranges from 25% to 35%. To maximize aroma preservation a process known as aroma stripping can be instigated between extraction and concentration. The aroma is removed through the medium of a stripping gas and is quickly fed back to existing tea concentrate.
Extraction process of instant tea

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Lima beans postharvest

The lima bean is named after Lima, Peru and very popular bean with its buttery flavor and creamy texture.

Just after harvesting pod and beans are separated by a machine. The pod may be returned the soil or ensilaged for cattle feed, and the bean are taken to the plant where they are washed, blanched cooled and graded.

Smaller beans are blanched at 200 ° F for 2.5 to 3 minutes. More mature beans are blanched 4 to 5 minutes at 190 ° F to prevent bursting of the skins.

The beans then spread in thin layers on drying trays and stir occasionally during the drying process. Normally the drying process started at 120 °F and 130 °F raise this temperature gradually to 150 °F.

They are then washed and inspected for foreign material and then frozen individually and packaged in plastic pouches.
Lima beans postharvest 

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Cold pressing of olives oil

After olives are harvested and cleaned within 72 hrs they must be crushed and made into a pulp. After that point, the pulp is cold pressed in the absence of light and oxygen and the oil expelled and bottled in opaque glass bottles.

In olive oil processing, cold pressed means that the olives or the press are not heated or treated with hot water. The maximum allowed temperature for extra virgin oil is 25 °C. Heat would give a higher yield of oil during the pressing, but would compromise the quality and flavor.

Cold press is very important for the first pressing of extra virgin olive oil. A cold press retains all the nutrient benefits of the raw fruit. Using this method 90% of the oil is extracted from the olives.

An olive oil extracted from the first cold press of unripe green olives, characterized by having a high level of astringency. Good quality oil is fragrant with a fine taste, free of sharpness and acridity.
Cold pressing of olives oil

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Mannitol as a sweetener

Mannitol is a polyhydric alcohol having the formula C6H8(OH)6. The aldehyde group (C=O) of mannose is replaced by a hydroxyl group (OH). Its molecular weight of 182, prepared commercially by the reduction of dextrose.  It is used in chewing gum, pharmaceuticals, and in some foods.

D-mannitol is widespread in nature. It is naturally occurring sweetener in many plants, algae and molds. It occurs in the sap of manna tree, an ash native of southern Italy, and can also be made by the reduction of either of the monosaccharides, mannose or galactose.

It is sparingly soluble in many organic solvents such as ethanol (1.2 g/100 mL) and glycerol (5.5 g/100 mL), and practically insoluble in ether ketones, and hydrocarbons.

Industrially, it is produced by electrochemical reduction or catalytic hydrogenation methods. While it is similar to sorbitol in many respects, it is less soluble than sorbitol.

Mannitol is commonly used as a nutritive sweetener, stabilizer, humectants and bulking agent in foods and supplements.

As sweetener mannitol may be effective in preventing tooth decay, since oral bacterial are unable to form acid from mannitol.
Mannitol as a sweetener

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