Hydrogenation in Food Production: Process, Benefits, and Health Implications

The hydrogenation process in food production involves chemically adding hydrogen to unsaturated fatty acids found in oils and fats. This reaction transforms liquid oils into semi-solid or solid states, which are commonly used in products like margarine, shortening, and baked goods.

To begin the process, the oil is heated and exposed to hydrogen gas under high pressure. A catalyst, typically nickel or platinum, is used to accelerate the reaction. During hydrogenation, hydrogen atoms bond with the carbon-carbon double bonds in unsaturated fatty acids, converting them into single bonds and resulting in the formation of saturated fats. These saturated fats are more stable and have a longer shelf life.

The primary purpose of hydrogenation is to enhance the texture and stability of oils, increasing their melting point, which is beneficial for creating products like spreads and pastries. Additionally, hydrogenation makes oils less susceptible to oxidation, which helps prevent rancidity and prolongs the shelf life of food products.

However, hydrogenation can also lead to the creation of trans fats, which are associated with negative health effects, such as raising LDL (bad) cholesterol and lowering HDL (good) cholesterol, thereby increasing the risk of heart disease. As a result, there has been a growing effort to reduce or eliminate trans fats from food products.

In response, the food industry has been exploring alternative methods to achieve similar outcomes without the associated health risks. For example, interesterification rearranges the fatty acids in oils without generating trans fats. Additionally, the use of green hydrogen, produced through renewable energy sources, is being investigated to make the hydrogenation process more environmentally sustainable.

Understanding the hydrogenation process is crucial for both food manufacturers and consumers, as it directly impacts the nutritional quality and safety of the foods we consume.
Hydrogenation in Food Production: Process, Benefits, and Health Implications

Mechanism of ohmic heating process

Both irradiation and microwave heating employ radiant energies which effect foods when their energy is absorbed, whereas ohmic heating raises the temperature of foods by passing an electrical current through the food.

When electrical current flows through a conductor, the motion of charges within the material results in agitation of molecules therein. This results in increased temperature.

Within metallic conductor, the moving charges are electrons; however, within food materials, the charges are usually ions or other charged molecules such as protein, which migrate to the electrode of opposite polarity.

Because heating occurs by internal energy generation within the conductor, the method results in a remarkably even distribution of temperatures within the material. Ohmic heating is alternatively called resistance heating or direct resistance heating. This due to food system serves as an electrical resistance.
Mechanism of ohmic heating process

Food processing: Malting

Malting is the limited germination of cereal grains or occasionally, the seeds of pulses (peas and beans), under controlled conditions. The starting and stopping of botanical growth is expertly timed by the maltster to achieve a minimum malting loss and maximum malt modification.

Sometime malt is used ‘green’ (undried), but it is usually used after drying in the sum or in a current of warm water. The three main steps of the malting process are steeping, germination and kilning. Final stage of malting process is kilning, enzyme activities decline as malt color and malt flavor develop.

This converts the endosperm of the grain into simple sugars which later be partially converted by fermentation into alcohol.

In the industrialized regions of the world, malt made from barley is by far the most important, but malts are, or have been, made from wheat, rye, oats, triticale, maize, sorghum, various millets and even rice.
Food processing: Malting

What is tomato paste?

The fruit of an annual plant or short-lived perennial Lycopersicon esculentum of which some varieties grow to over 2.5 m high whilst others are low bushes.

Tomato paste is tomato puree that has been cooked to remove almost all moisture. Tomato paste is thus a concentrated source of flavor, color and thickening power. It is also an effective emulsion stabilizer.

It is obtained by removal of peel and seeds from tomatoes, followed by concentration of juice by evaporation under vacuum. Good quality tomato paste is a homogenous mass, with a high density, without foreign bodies with a red color, an agreeable taste and smell, close to those of fresh tomatoes.

Tomato paste lends a deeper, rounded tomato flavor and color to many slow-simmered paste sauces as well as to Italian soups and stews.

A rule of thumbs for formulating with tomato paste is as follows:
Tomato paste/water 1:1 ratio ≈ puree
Tomato paste/water 1:2 ratio ≈ sauce
Tomato paste/water 1:3 ratio ≈ juice
What is tomato paste?

Food pretreatment before processing

It is generally necessary for foods to undergo a treatment prior to the canning process, but these pretreatment differ depending on the foods.

The purpose of pretreatment is to help preserve color nutrients, flavor and overall quality.  Specific vegetables and fruits are high in different vitamins. It is important to know how the vitamin is destroyed and what pretreatment will stop the loss.

Some pretreatment are applied to many different foods. One of these, usually applied to vegetables, is blanching. Vegetables may be pretreated before drying, just as they are before freezing, by blanching in boiling water or steam.

Blanching is steam or water is a method of partially cooking the food, typically just to the point of inactivating the enzymes and also used to break the skins of fruits that have a waxy coating.

Steam blanching preserves more of the food’s natural vitamins and minerals than water blanching but requires slightly longer processing period.

Vegetables are first washed, usually in water and detergent, then rinsed. They are then passed over belts, where any remaining foreign matter, such as weeds or stalks, can be removed by hand.

Blanching consists of heat in steam (no pressure) or hot water (usually about 98.9 ° C) until the temperature of the food is brought up to about 82.2 C – 87.8 ° C in all parts, the cooling in water.

Some vegetables cannot be blanched at these high temperatures without adversely affecting their taste and texture. In such cases, catalase is used as the test enzyme for sufficiency of blanch.

Off flavors may result, though even in the absence of catalase, if peroxidase is present.
Food pretreatment before processing

Canning of raspberries

Raspberries are an important commercial fruit crop, widely grown in all temperate regions of the world. The raspberry is the edible fruit of a multitude of plant species in the genus Rubus. Red and black raspberries are canned by the same methods.

Raspberries should be picked when they are ripe but firm. The raspberries are then conveyed to the factory in crates of the shallow boxes to prevent bruising or crushing of the fruit.

Raspberries, like most berries, require considerable hand labor in preparing for canning. Berries are washed and sorted to remove the deformed and overripe berries unfit for canning. Raspberries are size graded using slat riddled.

The berries are placed in cans as they are washed, the filled can inverted to drain off the excess water, and the cans generally placed on a belt or some other type of filled can conveyor to carry them to the syruper.

The berries are canned in heavy syrup (50°-55° Brix) for dessert purpose, or in water for use in pies. If syrup is used, it should be added at a temperatue of at least 93 ° C. Some canners believe that the use of syrup that is too hot causes shrinkage of the berries.

Cans are exhausted until a center temperature of 18 °C is reached. This requires approximately 5-6 min at 100 °C.
Canning of raspberries

Processing of Feta cheese

Feta cheese belongs to the co-called ‘white pickled’ group of cheeses. It requires simple equipment for its manufacture and it keeps well.

Traditional Feta cheese is produced mainly in the mountainous regions of Greece from mixture of sheep’s milk and cow’s and/or goat’s milk. It is a table cheese, a favored ingredient in salads and pastries.

The milk is heated to 32-34 ° C and traditional rennet extract from lamb’s /kid’s abomasa is added to give a coagulum ready for cutting after 50 min. Rennet mixed is at 120 ml/1000g milk.

Coagulation process is essential for the development of a uniformed gel and finally Feta with firm texture.

The coagulum is the cut into 2 -3 cm cubes, left for 5-10 min in whey, and then transferred gradually into circular molds, placed on an inclined table, and turned occasionally. This facilitates whey drainage.

Feta cheese

The curd is stored overnight in a room maintained at 18 ° C and 85% relative humidity. At this temperature and RH a product of better texture and flavor is produced. The curd should achieve pH of 4.7 in about 24 hours

When the curd is firm enough, it is then removed from the molds, cut into slices and rubbed or sprinkled them with granulated salt. The cheeses are left until a slimy layer has formed within 1 to 2 weeks; then the surfaces are cleaned and the cheeses placed into barrels, leaving no space between slices.

Brine of 6-8% NCL is added and the barrels are closed. The cheese slices remain in ripening rooms until their pH reaches 4.4-4.6 and then transferred to cold stores at 3-4 C. Maturations of Feta cheese actually begins before the curd making is finished and can be separated into two phases. The first one takes place simultaneously with dry salting in the ripening plants, at 18 ° C while the second one occurs during the storage of Feta in refrigeration.

Usually formed in square-shape blocks, Feta cheese has a somewhat grainy consistency (and is therefore crumbly), usually is white and has tangy and salty flavor.

Feta cheese can only be produced under strict product specifications in certain areas of Greece. Feta is registered as a Protected Designation of Origin (PDO) product.
Processing of Feta cheese

Food processing of Ohmic heating

Ohmic heating is one of the newest methods of heating foods. Ohmic heating’s major advantage is that is simultaneously heats solid pieces and liquids in a food with minimal destruction.

It has been shown that ohmic heaters can provide an interesting alternative to heat exchanger for thermal processing applications.

In this method the food is placed between two electrodes serving as an electrical resistor and an alternating electric current is passed through the circuit.

Due to the electrical resistance, heat is generated volumetrically in the form of internal energy throughout the food. The electrical energy is directly converted into the heat causing a temperature rise.

Hence, ohmic heating is sometimes also referred to as Joule heating, electrical resistance heating, direct electrical resistance heating, electro-heating or electro-conductive heating.

Ohmic heating has been practiced since the nineteenth century, when a number of patents were filed for heating of flowable materials.

In the twentieth century ohmic heating was practice in and off: first in the 1930s for electric pasteurization of milk, and later in the 1980s and 1990s for continuous flow sterilization and aseptic packaging for solid–liquid food mixtures.
Food processing of Ohmic heating

Smoking of fish

Smoking is often used to preserves and flavor meat, fish, and cheese, etc.  It is likely the practice of smoking meat and fish outdates the art of cooking in containers, as open-fire contact (roasting) with food must have been the earliest form of cooking even before earthen ware pots were made.

The importance of wood as fuel, with wood smoke as an integral part of that and perhaps later its utilization in food processing is tied to the same aspect of civilization.

At a dig in Bishkupin, Poland, scientists discovered a fish scales and bones of bass, bream, catfish, pike and roach showed the site to be an eight or tenth century fish smoking plant, which prepared large catches from Biskupin Lake for a large population.

Smoking foods is one of the most ancient food preservation process and in some communities one of the most important. Native Americans of the East Coats and Caribbean preserved fish and haunches of venison by stretching them over cane or wooden racks above a slow, fragrant fire of grass, herbs and mesquite or hardwood.

When Spanish expeditioner Hernando De Soto reached Tampa Bay, Florida, he studied the Timucua method of building strong wood scaffolds over the fore for the roasting of deer, dog, alligators, fish and snake.

Fish could easily be smoked. Before the invention of the chimney, houses normally had thick smoke above head level, slowly finding its way to the smoke hole. Hanging gutted fish on the rafters lightly preserved it by drying and partially cooking it.

More modern methods of smoking fish us formulation of liquid smoke to provide flavor and a range of methods of drying to reduce water activity on the surface. Most drying methods use heat to change the relative humidity of the air passing over the fish.
Smoking of fish

Processed cheese (or process cheese)

Process cheese is made from a mixture of natural cheeses and an emulsifier blended together with controlled heating.

It is prepared by comminuting and mixing with the aid of heat from selected cheddar cheese, although Swiss, Limburger, Brick and others are sometimes used.

The mixture is pasteurized for 3 minutes at 150 °F and salt is added. The careful selection of cheeses, emulsifying salts and processing factors allows making process cheeses of varied textures suitable for many end uses.

The emulsifier added is sodium citrate, disodium phosphate, or other additive that will be effective in binding the high fat content of the natural cheese ingredients with water that is added to the process cheese to produce a more soluble, homogenous, and smooth cheese that can withstand higher heat than natural cheese without coagulating.

Approximately one-third of the cheese produced in the United States is marketed as a pasteurized process cheese. Fast-food giants like McDonald’s and Burger King rely in the consistency in flavor and melting qualities of pasteurized process cheese.

The flavor of process cheese depends largely upon the favor o the cheese used which may be modified by flavoring materials added.

Process cheese sometimes called processed cheese or pasteurized process cheese, is convenient not only for food service, the primary user, but also retail because these cheese are available in regular and reduced-fat varieties, chinks, cubes, spreads, loafs, slices as well as in grated or shredded applications. Process cheese may be used in main dishes, for snacks and cheeseburgers, with cold cuts and salads on grilled or toasted sandwiches in numerous sandwich combinations and in casseroles.
Processed cheese (or process cheese)

What is prime pressed cocoa butter?

Prime pressed cocoa bitter is designed as the fat obtained from good quality cocoa nib commercially free form shell by means of mechanical (hydraulic) pressing. No subsequent refining other than filtration is employed.

Cocoa butter, which forms about 45%b of the bean is extracted by removing the beans from their pods and allowing them to ferment before they are dried, roasted, shelled and ground to the paste known as ‘cocoa liquor’ or ‘cocoa mass’.

The cocoa liquor is then by hydraulic, screw expelling or solvent extraction to produce cocoa butter. There is usually some oil remaining on the cocoa powder - it is impossible to take out all the fat simply by pressing.

Pressing liquor made from highest quality nibs gives the best quality cocoa butter which is designated ‘pure prime pressed’, but butter produced by expeller pressing of good quality nibs is almost equivalent. Solvent extraction is used only from extraction of cake residues from the expeller process or of other, waste, residues.

Prime pressed cocoa butter is usually used directly in chocolate without any further processing. This makes it unusual among fats in the most fats are refined before use to remove unwanted minor components such as free fatty acids, pigments, oxidation products and off-flavors.
What is prime pressed cocoa butter?

Impact of processing and storage to water soluble vitamins

Certain vitamins are sensitive to processing and storage. Processing medium or the environment is a critical factor in influencing the stability or retention of water soluble vitamin. Generally, the water soluble vitamins especially thiamin, riboflavin, and vitamin C , are more susceptible to losses due to leaching during washing and blanching.

Choy sum

Certain water soluble vitamin are susceptible to oxidation (thiamin and cobalamin), the processes are different from those for the fat soluble vitamins.

Water soluble vitamins are generally more heat heat-sensitive than fat soluble vitamins. Vitamin C and thiamin are the most heat sensitive. Thiamin is extremely water soluble and destroyed by heat is much can be leached into the cooking or storing liquids during preparation of both meats and vegetables. Losses in the making of soy flour are minimal, but losses in the making of soy flour into tofu stored in water are 85% or greater.

Vitamins stable at acidic pHs include ascorbic acid, niacin, free folacin and thiamin. Biotin, thiamin, free folic acid, pantothenic acid and ascorbic acid are loss more readily at alkaline pHs.

Physical factors also contribute to the loss of vitamins during processing and storage. Electromagnetic radiation in the visible and near ultraviolet region is one such factor.

Folic acid is easily lost during storage of fresh vegetables at room temperature and through many heat processes. Oxidative destruction of 50-95% of the folate can occur with protracted cooking or canning. Riboflavin and niacin are both relatively stable on heat preservation, although riboflavin is very sensitive to light and will undergo degradation in the present of both heat and light together.
Impact of processing and storage to water soluble vitamins

Production of fudge

The name fudge covers a wide range of products which are basically toffee formulation but in which sugar crystal has been developed during processing.

Fudge consists of oil, water and milk ingredients.  Normally fudge contains more sugar and milk than a toffee, but composition can vary between very wide limits. The hardness and texture of the final fudge are mainly determined by the water content, which in turn is controlled by the boiling temperature. The higher the temperature, the lower the water content and it will harder the final product.

Fudge is produced by boiling a caramel batch to 120 – 123 ° C, cooling it to about 105 ° C. It is then cats or spread on tables to allow crystallization to develop.

Fudge is a grained product, and some means of graining is required. This can be done by removing part of the cooked batch, cooling it and working it until crystallises, when it is added back to the remainder of the hot batch and thoroughly mixed in.

Whilst this is feasible it is not usual and use of fondant to provide seed crystal is almost universal. Usually about 5% is required but increasing the quality will produce finer crustal and a more plastic product.

In fudge applications, the fat works as a smoothing and shortening agent making the product less sticky.

Another very important function of the fat is as a flavour carrier which means that it needs to have very good flavor and flavour stability.
Production of fudge 

Steam rendering for animal fat

Nearly all animal fats, tallow or beef fat and lard, are obtained by rendering. The two predominant rendering processes are wet and dry rendering. Wet rendering produces the better quality oil while dry rendering produces the best quality protein.

Most of the edible animal fat produced in the United States is rendered by the steam process. In the steam rendering of high fat stock, 99.5% or more of the fat in the raw material is ordinary recovered.

The apparatus used is a vertical cylindrical steel autoclave or digester with a cone bottom, designed for a steam pressure of 40 to 60 pounds per square inch and a correspondingly high temperature. The comminuted fatty tissues are first heated to 50 °C – 60 °C and then quickly to 80 °C - 90 °C with direct steam.

The vessel is filled with the fatty material plus a small amount of water and steam is admitted to boil the water and displace the air.

The vessel is then closed except for a small vent, and the injection of steam is continued until the operating temperature and pressure are attained; then digestion is continued for a variable time depending upon the temperature and also the nature of the charge.

The usual digestion time is 4 to 6 hours. The process dissolves the tissue releasing the fat from proteinaceous material. The liquid fat floats on the top water, which can be separated thereby producing edible fat products where color, flavor and keeping quality are of great importance.
Steam rendering for animal fat

Food processing: quick freezing

The two basic ways to achieve the freezing of foods are quick and slow freezing. The technical features of the quick freezing process are ultra rapid freezing at very low temperatures (-30 to -40 ° C) designed to bring the inside the product to a temperature of -18°C as quickly as possible. Rapidly frozen foods have a much longer storage life than foods stored in cold stores.

The products that are generally preserved by quick freezing are meat, fish, some vegetables such as peas, spinach, cauliflower, carrots, beans etc.

When the quick freezing process is used, these liquids solidify to form extremely fine crystals of ice, and the cellular structure is left intact, whereas, in the ordinary freezing process, where low temperatures are reaching more slowly, the texture of the product is altered.

In quick freezing, large quantity of food can be frozen in a short period of time.

Quick freezing is a method of increasing the shelf-life of perishable foods by subjecting them to conditions of temperature low enough to inhibit the oxidative, enzymatic and microbial changes, which are responsible for the changes in flavor and color of foods.

Quick freezing is ideal for producing good quality frozen foods. The food freezes immediately and keeps its shape and appearance.

Quick freezing is obtained by one of the following methods:
*Freezing Tunnel or Blast Freezer
*By Direct Contact with Metal Plate Surfaces maintained at Low Temperatures
*By immersion in (or by Spraying)  a Low Temperature Liquid
Food processing: quick freezing 

Drum drying processing of milk

The main drying process of skim milk powder and whole milk powder is spray drying. However, drum drying and fluid-bed drying are used for special purposes.

In drum drying the milk is distributed on rotating, steam-heated drums, where the water evaporates.

Drum dryers were introduced into industries about 100 years ago and it starting with the double-drum dryer which features the feeding by nipping between two drums. J. A Just was one of the first inventors to receive –patent rights on a drum dryer with two rolls in 1902.

Drum dryer consists of one or more hollow metal cylindrical rolls or drums that are mounted to rotate on horizontal axes at a variable speed.

Using film evaporating systems, the milk is first pre-concentrated to 40-50% solids. A thin layer or film of product is dried over an internally steam-heated drum with steam pressure up to 620 kPa and 149 °C. Approximately 1.2 – 1.3 kg steam are required per kilogram of water evaporated.

The film dries as the drum rotates. The dried milk then is scraped from the drum surface, as they rotate, by metal scraper. The feeding materials can be slurries, paste, or solutions and final dried products are in the form of powders, flakes or chips.

The operating variables for a drum dryer include condensation of incoming product in an elevator, temperature of incoming product, steam pressure in drum, speed of drum, and height of product over drum.

In the process, relatively large particles are obtained.  It has poor dissolving properties and where sold for domestic use is subjected to further instantisation, which agglomerates granules and leads to a faster dissolution time.
Drum drying processing of milk 

Decaffeination of tea: carbon dioxide process

Caffeine is an alkaloid which stimulates the central nervous, muscular and circulatory systems. Too much caffeine in tea are not good for elderly people and caffeine sensitive patients.

Tea is decaffeinated by various methods. Briefly the tea is prewetted and extracted by some organic solvent such as dichloromethane or ethyl acetate. Alternatively, an extraction using supercritical carbon dioxide can be used. Supercritical carbon dioxide is the most widely used solvent for decaffeination of food products. The gas is odorless, tasteless and inert.

When highly pressurized, carbon dioxide assumes a supercritical state and has properties of both a solid and a fluid. At this point, it becomes an efficient solvent for caffeine.

The cp0ressed carbon dioxide is pumped into a chamber with tea. It extracts the caffeine, and the carbon dioxide is separated from the tea and carbon filtered to remove the caffeine.

Carbon dioxide processing leaves no toxic residues. In addition, extraction of the caffeine takes place at room temperature which protects product quality by preventing the breakdown of temperature-sensitive components.

After extraction occurs, the supercritical fluid turns back into a gas, so no solvent residue remains. CO2 decaffeinated teas best retain the original flavors of the teas.

Other advantages of supercritical CO2 as a decaffeination solvent:
*CO2 has suitable critical constant for this application
*CO2 in small amounts is physiological harmless an cause no environmental pollution
*CO2 is cheap, easily available and non flammable
Decaffeination of tea: carbon dioxide process 

Tocopherol losses in food

Naturally occurring vitamin E comprises tocopherols and tocotrienols. Processing and storage of foods can result in substantial tocopherol losses. Cooking of porridges of rolled oats and rye meal implies only minor effects on their tocopherol and tocotrienols contents.

Studies of alpha-tocopherol in UHT processed milk suggest that the processing conditions affect the subsequent losses, but that in all cases increased storage temperature led to increased rate of loss.

There was a loss of tocopherol reported in the study of potato chips. After only two weeks’ storage of the chips at room temperature, nearly half of the tocopherol was lost.

The losses were only slightly smaller during storage at freezer temperature.

Deep fat frying of fresh vegetable oil causes losses of about 10% but storage of fried foods, even at low temperature, may cause large losses.  The low content of alpha-tocopherol in frozen foods is surprising and indicates serious degradation even at 12 °C.

Boling of vegetables in water for up 30 minutes results in only minor losses of tocopherol.

Baking of white bread (200 °C, 30 minutes) destroyed of about 5% of the tocopherol in the crumb.

Tocopherol losses during microwave cooking are mainly caused by the effect of high temperature and not by microwaves as such. When sunflower oil was subjected to microwaves discontinuously for 120 min at two constant temperatures: namely 170 °C and less than 40 °C, tocopherol losses were 72% and 21%, respectively.
Tocopherol losses in food

Manufacturing of tomato paste

Tomato paste is usually considered as semifinished product because it is commonly used as an ingredient in other food products. Tomato paste and puree are important ingredients for pickles and sauces.

Its primary use is in tomato ketchup but it is also used in salsas, pizza and pasta sauce, sweet pickles sauce, tomato chutney sauces and other thick sauce. Functionally it provides flavor, color and consistency. 

Tomatoes are washed, trimmed and then heated to a ‘breaking’ temperature.

During processing, seeds are removed at the pulping and screening stages to improve flavor and color.

The tomatoes are chopped at room temperature and immediately, or within seconds of crushing, heated to a temperature range of 60 to 90° C.

To refine the juice, broken and pre-heated tomato pulps are screened by pumping to a series of extractors or cyclones using an initial screen with a sieve diameter of about 1 mm followed by a second screen with a sieve diameter of between 0.4 and 0.7 mm.

Tomato paste is made from tomato juice by evaporation to a predetermined percentage of soluble solid usually in a range of 20-37%.

During this processing step, tomato pulp is additionally exposed to elevated temperatures of 50-95% and a number of chemical reactions largely of non enzymatic hydrolytic and antioxidative origin, continue to affect its original composition.

Once the tomatoes have been turned into paste, it can be stored for up to 18 months. The manufacturer then sells the tomato paste to other companies that add spices, flavors and colors to turn the industrial tomato paste into products like ketchup or tomato sauce.
Manufacturing of tomato paste

Processing of tea: Orthodox method

Orthodox teas are made from selected leaf – two leaf and one bud formula. They were handpicked, taking at most the newest two leaves and the bud off the end of each branch.

Orthodox tea teas have larger fragments a bolder taste, and appear black in the cup. Traditional orthodox teas are shown more respect during the manufacturing procedure and the larger pieces of leaf give a more subtle quality to the infusion.

For both CTC and orthodox the basic stages of processing remain the same. The major differences lies in the yield per kg of made tea. While orthodox tea yields nearly 200 cups per kg in the case of CTC it is more than double.

The orthodox method requires more fine leaf and longer withering period (18-24 hours) than the CTC and therefore, it is more time consuming and expensive. Withering is the process through which green leaves lose moisture 50-55% in orthodox method.

In the CTC technique machines crush leaves prior to rolling, creating small globules, while in the orthodox system, leaves are rolled to form the distinct ‘twisted twig’ shape of orthodox tea. During rolling, twisting of leaves and some amount of maceration also occurs. After rolling or about 45 minutes, leaf is passed over a sifter to remove well rolled leaf, a process known as roll breaking.

Both methods CTC an orthodox breakdown the veins in the leaves and start the fermentation process. In orthodox manufacturing, fermentation is carried out by spreading rolled leaf in a layer of 2.5 to 7,5 thickness for 2 to 3 h.

The main orthodox the producers are Sri Lanka, Turkey, and Indonesia. India, Iran, Argentina, the other South American tea-growing countries and China also produce orthodox tea.
Processing of tea: Orthodox method