Processing and production of grape juice

A wide range of drinks can be made using extracted fruit juice or fruit pulp as the base material. Many are drunk as a pure juice without the addition of any other ingredients, but some are diluted with sugar syrup.

The Concord variety is chiefly used for the manufacture of grape juice. The grape are washed in acid or alkaline solution, then in water to remove spray residues, then destemmed and crushed by mechanical means.

The crushed grapes are heated to about 180 F to extract pigment from the skins, after which the heated materials subjected to mechanical pressure while enclosed on cotton press cloths. The juice is then filtered, pasteurized by heating to 1790 F, and stored in bulk in covered tanks at about 40 F. This provides for the separation of tartaric acid slats.

The juice is then siphoned off from the tartrate and treated with enzymes, which break down pectin, or with casein for purposes of clarification. It is then filtered and bottled. The bottles are capped and then pasteurized by heating in water at 170 F for 30 min.

To produce grape juice concentrate, grape juice is subjected to heat and evaporation until concentrated. Volatile components can be recovered from the process, and they can be added back to the concentrate. The concentrated juice may be frozen in retail sized containers, or it may be shipped in large tanks to food processors for remanufacturing process.

In most commercial operations, the continuous pressing method is used. Hot pressing is appropriate for deeplypigmented grapes where maximum colour extraction is desired. Whereas, the immediate orcold press procedure is necessary to maintain the initial colour of light coloured grapes.
Processing and production of grape juice 

Manufacturing of fruit jam

Jam is made from crushed or ground fruit. The end product is less firm than jelly, but still holds its shape. The fruit content must be at least 40%. In mixed fruit jams the first-named fruit must be at least 50% of the total fruit. The total sugar content must be no less than 68%. In tropical climates, 70% sugar is preferable.

Fruit furnishes the flavor and part of the needed pectin and acid. Some irregular and imperfect fruit can be used.

In the manufacture of jam, the deforested fruit is passed through a pulper that allows essentially all the berries with the seeds to pass through the strainer.

Sugar and water are then added the amount of sugar depending on whether the frozen product was packed with or without sugar. About 0.1 – 0.15% dispersed pectin is then added and the product is heated in open kettles to concentrate it to soluble solids content about 68%.

When a commercial pectin is added, fully ripe fruit can be used. The use of this added pectin also increases the yield from a recipe.

Citric acid solution is then added to adjust the pH to 3.3 and the fruit is packed in glass jars and vacuum capped. The jars should be clean and sterilised. The ideal temperature for pouring is 82-85°C. Hotter than this and condensation will form under the lid. This will drop down and dilute the jam, allowing mould to grow. Colder than this and the jam will be difficult to pour.
Manufacturing of fruit jam

Fruit canning

Food is preserved by using methods that destroy or hinder the growth of microorganisms, such as molds, yeast and bacteria. These organisms may be present in the soil, on the food, in the air, on equipment or on work surfaces.

Yeasts, molds and bacteria must be destroyed during processing to prevent the food from spoiling. The correct amount of time to process varies with the kind of food. Sufficient heat for a specified length of time kills microorganisms and insures a safe product.

Canning is a method of preserving food by first sealing it in air-tight jars, cans or pouches, and then heating it to a temperature that destroys contaminating microorganisms that can either be of health or spoilage concern because of the danger posed by several spore-forming thermo-resistant microorganisms, such as Clostridium botulinum (the causative agent of botulism).

Canning is also to retain nutrients and optimum quality, preserve fruits and vegetables when at their peak of freshness. All fruit preserved by canning should be heat-processed to attain commercial sterility.

Whereas vegetables and certain other foods require the application of high temperature (240°F, 250°F) or higher for significance lengths of time to attain commercial sterility, most fruits sufficiently acid (PH usually below 4.5) that commercial sterility can be attained by heating the containers in boiling water to the point where all parts of the product reach a temperature of 180°F – 200°F.

After heat sterilization, containers are quickly cooled to prevent overcooking. Containers may be quick cooled by adding water to the cooker under air pressure or by conveying the containers from the cooker to a rotary cooler equipped with a cold-water spray.

Adding syrup to canned fruit helps to retain its flavor, color, and shape. It does not prevent spoilage of these foods.
Fruit canning

Production and processing of raisins

Raisins are the second most important product of the grapevine wine, being the first. The quality of raisins depends on the size of the raisins berries, the uniformity and brilliance of the berry color, the condition of the berry surface, the texture of the skin and pulp in the berry, moisture content, chemical position and presence of decay, mold, yeast and foreign matter.

Raisins are produced from grapes by sun during and artificial drying. In the traditional drying method, grape bunches are spread over either the ground or on a platform or on wooden trays in a thin layer between the rows of grapes vines.

The trays are tilted to face the sun. After they are partially dried, the grape bunches are turned and allowed to dry to the point where no juice can be pressed out. The trays are then stacked, and the air drying is continued in the shade until moisture content of about 17% reached. After drying, the raisins are placed in sweat boxes to equilibrate, or to even out, the moisture that is present, and then they are packed in retail size containers or in larger containers to be sold to the bakery trade.

This method of drying is most cost-effective and takes approximately 8-10 days to produce dried products.

In artificial drying, grapes are first dipped n 0.25 – 1 % lye (sodium hydroxide) solution at 200 – 212 degree F for 2 – 5 sec to remove a natural wax that impedes drying and to check or crack the skin of the grape to facilitate drying

They are then washed, placed on trays, and treated with sulfur dioxide to prevent enzymatic and nonenzymatic browning during drying. Hence instead of having the dark brown color of raisins that normally be expected, the raisins will be of a light yellow color when dried.

Raisins are dried at temperatures not exceeding 165 degree F and at a low relative humidity. After the moisture content has been lowered to about 16 – 18%, the raisins are packaged in containers of various sizes to be sold at retail or for use by the food industry.

In California, light-colored raisins are produced mostly by the golden bleach process. First, Thompson Seedless grapes are sorted, then they are dipped to produce slight checking cracking of the skins, and they are cooled and washed in a spray of cold water. They are exposed to the fumes of burning sulfur in a sulfur house. After being sulfured, the grapes are dehydrated at a temperature of 140 to 160 degree F.
Production and processing of raisins

Processing of cranberries jelly and sauce

About 80% of the cranberry crop is processed. Some of the processed berries are made directly into cranberry juice drinks and traditional types of cranberries sauces.

In manufacturing cranberries jelly, the clear juice from the boiled fruit that has been passed through a pulper, is mixed with sugar, about 0.35% of dispersed pectin is added and no water used.

The mixture is heated briefly to bring the soluble solid content to 65% and citric solution is added to regulate the pH 3.0 to 3.2.

Cranberry sauce production starts with frozen fruit. After the frozen fruit is dumped into warm water for defrosting the slurry passes through scavenger and rock trap prior dewatering and cooking.

For whole cranberry sauce carefully hand-sorted berries are added to the puree after the first cooking. No additional pectin is needed to set the jellied sauce because the berries have an abundance of natural pectin.

Both cranberry sauce and cranberry jelly are preserved by heat processing. If the products are heated to about 190 F (87.8 C) prior to filling into containers further heating is not necessary to attain commercial after sealing the containers.

If packed at lower temperatures, the containers should be sealed and heated in a water bath or with spray of water at 185 – 200 F (85-93.3 C) prior to cooling.
Processing of cranberries jelly and sauce

Fruit of strawberries

The strawberry (Fragaria spp.) is the most popular type of berry fruit in the world. While there are more than 600 varieties of strawberries that differ in flavor, size, and texture, they all have the same characteristics heart shape, red flesh with yellow seeds piercing the surface, small, regal, leafy green caps, and stems that adorn their crown.

Strawberries are usually picked with the calyx or cap intact, since this enhances the keeping quality of the fruit. For processing, the berries are picked without the cap. The berries are placed in baskets of 1 Ib (454 g) capacity, and the baskets are placed in crates for transportation to the processing plant.

At the processing plant the berries are washed, inspected on belts to remove green and rotten specimens, and then repacked in baskets and crates for shipment as fresh products. They are then cooled to 31 to 32 degree F and should be held at this temperature until sold to the consumer. In this condition, they have a storage life of about 10 days. In some cases, strawberries for the fresh trade are precooled in refrigerated water.

They are eaten fresh, often with cream. They are also used as a filling for pastries, pies and cakes. Strawberries are an excellent source of vitamins C and K, dietary fiber, and flavonoids. They are also a very good source of manganese, panthotenic acid, vitamin B1, and iodine.
Fruit of strawberries

Defining fruit juice

Fruit juices are common beverages prepared from fruit such as organism grapes, apples, or more exotic fruits like guavas or papayas.

Compared with numerous beverages available today, fruit juice remains a nutritious choice.

Most red or orange-colored juices are rich in beta carotene. Thus red or pink grapefruit juice has more beta carotene than white. The champion is carrot juice: and eight-ounce glass supplies six times the amount recommended by most experts.

Fresh fruit juices are excellent sources of vitamin C and potassium. Their caloric content is derived almost exclusively from simple sugars.

Freshly squeezed juice usually has the highest vitamin C content, followed by juice made from frozen concentrate. The vitamin C content may have been depleted in the processing of commercially available juices.

In term of processing, fruit juice from concentrate may be defined as the product obtained by replacing the water in the concentrated fruit juice that was extracted from the juice during concentration.

If appropriate, pulp and cells that were removed during the process of producing the fruit juice, may be added back. In the reconstitution process, the water used must possess appropriate characteristics, particularly from the chemical, microbiological and organoleptic viewpoints.
Defining fruit juice

Apple juice processing

The majority of the processing apples are sort-outs from fresh market packing line. The volume available depends on fresh market demand and the quality of the current apple crop.

Apples are processed into a variety of products, but by far the largest volume of processed apple products is in the form of juice.

Apples are brought to the processing building and dumped by the truckload or out the apple bins.

Fruit are then spray washed and sorted. Depending on process logistics, clean, sorted fruit may be stored. Sorting and trimming of apples to remove damaged or decayed fruit is mandatory. If not removed, damaged or decayed fruit may also impart off flavors to the finished products.

Before pressing, whole apples are ground into a mash or pulp for extraction. This mashing process sis accomplished with either disintegrator, hammer, or grating mill.

The type of extraction equipment may dictate the chopping method to achieve highest efficiency. More common types of presses apply pressure via hydraulic, pneumatic, screw, basket or travelling belt methods.

In traditional milling-pressing operations, the yields are 70-80% w/w and even lower (about 65%) for stored apples. However, through use of enzyme liquefaction and membrane filtration, the apple juice yields can be as high as 98%.

For the ‘natural’ look associated with fresh apple cider, the ground apple is treated with ascorbic acid before pressing to minimize browning.

Apple juice is processed and sold in many forms. Fresh apple juice or sweet cider is considered to be product of sound, ripe fruit that has been pressed and bottled or packaged with no form of preservation being used, other than refrigeration.
Apple juice processing

Manufacture of cranberry sauce

Large amounts of cranberries are used to produce cranberries jelly and cranberry sauce, both retailed as canned products.

The first can cranberry sauce was packed in Hanson, Massachusetts in 1919, about 100 years after cranberry cultivation began in North America.

In the manufacture of cranberry sauce, water, about twice, as much as fruit and about 0.3% of dispersed pectin are mixed together.

The mixture is then cooked to 102.2 ° C and evaporated in an open steam kettle to a soluble solids content of 65%. Citric acid solution is then added to bring the pH to 3.0 – 3.4.

Whole cranberry sauce should not be cooked to a point where it sets to a solid gel, but should flow slowly when poured into a dish.
Manufacture of cranberry sauce

Processing of raspberries

Berries designed for processing are picked at a full to dark red stage, when fruit adhesion is minimal and machines can easily dislodge berries by using a shaking system. Fresh berries are transported directly from the grower or packer to the processor. Berries are washed and sorted to remove the deformed and overripe berries unfit for canning.

The berries should be shaken gently onto a wide white inspection belt, where inspectors will remove any foreign bodies such as calices, insects, leaf, twig and stones.

The berries should be clean and fee of rot or significant mold and posses typical color and flavor.

Raspberries are size graded using slat riddles. The berries are canned in heavy syrup (50-55 °Brix) foe dessert purpose or in water for use in pies.

Cans are exhausted until a center temperature of 18 ° C is reached.

For processing of puree, after washing the berries are either frozen in drums or totes for further processing or conveyed to a chopper or disintegrator.

After chopping, the berry is sieved or screened in a pulper/finisher to remove extraneours material (leaves, cap) and a homogenous puree is produced.

For seedless raspberry puree is produced using a screen of .045 in and screens of .060 or .125 in would be used for a raspberry puree with seeds.
Processing of raspberries