Apple pectin extraction

Pectin is a family of complex variable polysaccharides extracted from the primary cell wall of higher plants. Apple pectin is a hydrophilic colloid that is widely used in the processing of fruit drinks, jams, ice creams, jelly and many confectionery products as a food processing ingredient.

Pectin also being used in pharmaceutical preparation such as medical formulations for stabilizing the suspensions.

Pectin in apple pomace is mainly present in the form of protopectin, an acid soluble polysaccharide. The conventional juice extraction process removes 75 % of fresh weight as juice and 25 % remaining portion is called as pomace. Apple pomace is the by-product left after extraction of apple juice, which is a major processing waste in the apple processing industry.

The most commonly used method for extracting pectin from plant tissue is by heating the plant sample in acidified water.

Traditionally acid solutions are used to extract pectin from plant tissues. The acids employed can be strong acids like mineral acids (hydrochloric acid, sulphuric acid, nitric acid) or weak food grade acids (citric acid). The addition of extra chelating agents such as EDTA to the extraction mixture helps in easy release of pectin from cell wall.

The extraction is a multistage physicochemical phenomenon which involves the acid solubilization of the pectic materials under different pH, temperature and duration conditions generally in the range of 1.3-3.0, 60-100°C and 20-360 minutes respectively.

The solvent precipitate mixture is then mixed till the pectin floats and removed by using cheese cloth followed by drying.

Apple pomace is reported to contain about 18-19 % pectin on moisture free basis and 13.3 % on dry weight basis.
Apple pectin extraction

Production of dates juice

Dates fruit are a good source of sugars, fibers, and minerals, exhibiting many beneficial health effects such as being antioxidant, antimutagenic, antibacterial, antitumoral, and antifungal. Date juice extraction system results in a main product (date juice) and a by-product (presscake).

Date juice is made by dissolving and diluting soluble solids of date in water and removing insoluble solids. In this operation, stirring, heating, and macerating the date can increase the yield of the process. This product is sometimes consumed as a drink. In contrast with other fruits, date juice cannot be extracted by pressing because of high total soluble solid content.

Crude juice contains soluble and insoluble solids as well as foreign matter. Several technologies have been employed for clarification of date juice, such as juice pretreatment by boiling, precipitating or hydrolyzing colloids by enzyme, removing insoluble foreign matters by means of filtration or centrifugation, decolorization using activated carbon or ion exchange, removing the minerals using chemicals or ion exchange, and removing high molecular weight compounds by foaming.

Juice is pasteurized at 85°C to inactivate the enzyme, cooled and centrifuged at 3000 rpm to get clear juice. Date juice was found to be rich in reducing sugars (16.1%) and total sugars (18.3%).
Production of dates juice

Food processing: 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.
Food processing: Prime pressed cocoa butter

Expeller pressed process of cocoa butter

Expeller cocoa bitter is the fat prepared by the expeller process from cocoa beans singly or in combination with cocoa nib, cocoa mass, cocoa presscake and low fat cocoa presscake. In the expeller, extrusion, or screw press, slightly different conditions prevail during extraction.

Expeller cocoa butter usually has a stronger flavor and darker color than prime cocoa butter and is filtered with carbon or otherwise treated prior to use. The nib is normally steamed to assist the separation – chemically, the cocoa butter is the same as prime pressed. Expellers are also used to extract the fat from whole beans.

Often, expeller pressing is often applied to poorer grade nibs and may be assisted by steam treatment. It also used in some winnowing products, in which case the resultant cocoa butter is usually subjected to a refining process.

Expeller presses operate by using a rotating screw to force the material being extracted into tapering tube. The tube has slits along its length and terminates in a cone-shaped device which can be adjusted to vary the size of the outlet.

As material passes along the tube it is subject both to continuously increasing pressure and to the shearing action of the screw. Cocoa butter is expressed through the slots in the sides of the tubes, while flakes of press cake emerge from the outlet at the end of the tube.
Expeller pressed process of cocoa butter

Citrus juice processing

Fruit processing can only preserve the raw product quality, not greatly improve it. To produce consistently high quality juices and beverages it is important to start with the very highest quality fruit.

Traditionally, citrus processing is a mechanical process, which begin with the fruit sorted, followed by squeezed, milled and juiced.

After the fruit is graded to eliminate unsound fruit, it is washed; it is sized for each extractor to obtain a maximum yield of good quality juice. The juice extraction of juice from citrus fruit is generally done in one of two ways. Even though there are other juice extractors that differ somewhat, the FMC cup extractors and the Brown reamers set the standard in juice extraction equipment.

Both extractors are widely used and are known to produce high-quality citrus juices. The extractors quipped with large reamers or cups will primarily be used for grapefruit and the smaller reamers or cups will b used for lemons or limes.

The yield and quality of the juice depend on the fruit and on the efficiency of the machinery. Cloudiness of some citrus products is related to pectin, which requires pasteurization at a high temperature to inactivate the enzyme before the juices are packed.
Citrus juice processing

Decaffeination of tea by carbon dioxide supercritical 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 compressed 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 by carbon dioxide supercritical process

Processing of animal fats

For centuries animal fat was the principle edible source. Handing and processing animal fats have evolved from the primitive to state-of-the-art processing equipment and technology. Processing of animal fat for edible use may ranges from simple to complex.

If fat is selectively removed from the animal carcass and carefully rendered, the result product can be simply filtered to remove particulate.

For more complex products with more rigorous quality specifications, the complete processing train of caustic refining, bleaching, hydrogenation, blending and deodorization is used.

Animal fats recovered from fatty tissues by cooking processes known as rendering. The two predominant rendering processes are wet and dry rendering.

In wet rendering, the fatty tissue is heated under steam pressure, thus rupturing the cells and liberating the fat.  The lard produced by this method of rendering is known as ‘prime steam lard’. In addition to lard, tallow and whale oil also usually steam rendered. The wet process is preferred for edible animal fats.

In dry rendering, the fatty tissue is heated in jacketed drums with agitation until the fats is released. Presently, centrifuges are used to separates the fat from water and protein. The dry rendering process is preferred for inedible products.
Processing of animal fats

Extraction of Fruit Juice

Global fruit juice sales hit the 54 billion liter (BnL) mark in 2007 and are forecast to rise 15% by 2011 to 62 bnl.

Western European currently consume an average of 31 L of juice a year per capita. Juice is growing fast in Eastern Europeans (18 L are consumed annually per capita in Russia) as well as in India and China.

The extraction of juice from fruit is an ancient art dating from the earliest of records where wine is often mentioned.

Fermentation of fruit juice so the alcohol content preserved the fermented juice was one of the earliest forms of food preservation by the human species.

Preserved fruit juices keep their fresh taste and attractive color as long as they are not heated for too long or at too high a temperature. Prolonged boiling or heating changes the taste except with tomato and apricot juice.

Manufacturer of fruit juice has progressed from the farm or cottage industry into the efficient technology of modern food processing with the rapid changes in most technologies.

Throughout the temperature area of the world, fruits used for the major quantities of juices are citrus, pome and grape or vine fruits.

Hand picked fruit is generally of good quality and needs little pre-press treatment, but the growth of automatic harvesting, particularly with apples, creates may new problems of debris and dirt such as leaves stones and twigs, all of which need to be removed prior to pulping.

Methods of extracting fruit juices are dependent upon the structure and edible portion of the fruit.

Preservation methods include thermal treatments, freezing, chilling, concentration and for some clear juices, fine filtration.

Juice may taken apart by removing volatile flavour components, water, bitterness and acidity and then recombined to produce a consistent product. Fruit derived bases may be manufactured from the remaining fruit material after the juice has been extracted.

Pasteurization is often required to stabilize the product by removing microorganisms that could produce fermentation and/or spoilage, affecting clarity, taste and shelf life.
Extraction of Fruit Juice