Fruits and vegetables processing

 

 Preparation of Fruits and vegetables should be prepared for preservation as soon as possible after harvesting, in any case within 4 to 48 hours. The spoilage increases rapidly as time passes.

Good manufacturing practice (GMP)

It is a system for ensuring that products are consistently produced and controlled according to quality standards. The following practices are therefore recommended each time before storage of any food commodities at home scale:

Wash your hands thoroughly with hot water and soap before beginning to prepare food.

 Make sure that kitchen utensils and appliances are well cleaned and disinfected.

Always store food in a clean place.

 Use herbs and spices as little as possible, because they are an important source of contamination.

Use clean and pure salt only if the salt is not pure, heat it on a dry, metal sheet above the fire. 

Allow only clean drinking water to come in contact with fruits and vegetables. 

Never allow anyone who is sick or has open wounds to come in contact with food that is to be preserved.

Fruits and vegetables processing at home

These operations include washing, sorting, peeling, cutting or grinding and blanching, among others.The main focus is that the raw material must be processed as soon as possible (between 4 and 48 hours after it is harvested), to prevent spoilage.

Cleaning and washing

 First, the fruits or vegetables have to be thoroughly cleaned to remove any dirt or insecticide residues. This cleaning process usually involves washing the products under a faucet with running drinking-water or in a bucket with clean water that is regularly refreshed. When cleaning leafy vegetables, it is best to first remove the stems. Some types of fruit, such as cherries, strawberries and mushrooms are not washed, because this would actually increase the spread of micro-organisms. It is also not advisable to wash cucumbers, because this shortens their shelf-life. 

 Lye dip 

Some products, such as plums and grapes, are immersed for 5-15 seconds in a pan of hot, almost boiling, lye (NaOH; 10-20g lye/litre water) to make the peel rough and to thereby speed up the general drying process. The peel then also separates more readily from the fruit, which makes it easier to remove. After such a treatment, the fruit has to be rinsed vigorously with cold water to remove the lye residues. Lemon juice can also be used to neutralize any remaining lye residues. The disadvantages of using lye are that the food can become discoloured and the metal pan could become corroded.

 Sorting 

To achieve a uniformly sized product, fruits and vegetables are sorted immediately after cleaning according to their size, shape, weight or colour. Sorting by size is especially important if the products are to be dried or heated, because their size will determine how much time will be needed for these processes. 

Peeling

 Many types of fruits and vegetables have to be peeled in order to be preserved. This can easily be done with a stainless steel knife. It is extremely important that the knife be made of stainless steel because this will prevent the discolouration of the plant tissues. 

It is best to first submerge citrus fruits, tomatoes and peaches, whose peels are all securely connected to the fruit, in hot water for 1 ½ to 3 minutes. The softened peel can then be removed without too much effort. 

Cutting

 Cutting is important because you will need approximately uniform pieces for the heating, drying and packing stages. Fruits and vegetables are usually cut into cubes, thin slices, rings or shreds. The cutting utensils have to be sharp and clean to prevent micro-organisms from entering the food.

 From the moment they are cut, the quality of the products decreases due to the release of enzymes and nutrients for micro-organisms. A decrease in quality is also caused by the damage done to the plant tissues.

 Blanching

 Blanching is done by immersing fruits or vegetables in water at a temperature of 90-95° C. Exposing them to steam is also possible. The result is that fruits and vegetables become somewhat soft and the enzymes are inactivated. Leafy vegetables shrink in this process and some of the micro-organisms die. Blanching is done before a product is dried in order to prevent unwanted colour and odour changes and an excessive loss of vitamins. 

Fruit that does not change colour generally does not need to be blanched. Onions and leek are not at all suited for blanching. Blanching is quite simple. The only thing you need is a large pan with a lid and a metal, or in any case heat-resistant, colander. 

The disadvantage of this blanching method is that many vitamins are lost in the hot water. Steaming is therefore a better alternative. Only a small amount of water has to be added to the pan and brought to the boil.

Packaging and Storage

Packaging of fresh produce using polymeric films has been practiced for several decades to contain and protect fruits and vegetables from environmental contaminants. Moreover, perforated polymeric packaging film has long been used successfully to reduce moisture loss from produce during storage, shipment, and display by reducing the magnitude of the moisture vapor deficit between the produce and its immediate in-package environment.

 In more current times, un-perforated polymeric film packages have been used to minimize moisture loss and reduce respiration rate of produce commodities; most recently minimally processed fruits and vegetables have been packaged in polymeric film in an effort to maintain product quality while extending shelf-life.
Most vegetables, like carrots, potatoes, broccoli, cabbage and celery should be stored in a plastic bag or container in the crisper of your fridge. Mushrooms are best stored in a paper bag. Vegetables should be stored in a different part of the fridge than fruit. This will prevent them from ripening too fast.
In A Cool, Dry Place. 

Keep bananas, tomatoes, potatoes in a cool, dry area, not in the fridge. Store your apples in the refrigerator. Freezing fruits at home is a fast and convenient way to preserve produce at their peak maturity and nutritional quality.
Non-cherry stone fruits, avocados, tomatoes, mangoes, melons, apples, and pears will continue to ripen if left sitting out on a countertop, while items like bell peppers, grapes, all citrus, and berries will only deteriorate and should be refrigerated
Whole onions and shallots are best stored in a cool, dry, dark and well-ventilated room. ... Peeled onions can be stored in the fridge for 10–14 days, while sliced or cut onions can be refrigerated for 7–10 days.

                        

Packaging can be a major item of expense in produce

marketing, so the selection of suitable containers for commer-

cial-scale marketing requires careful consideration.

Besides providing a uniform-size package to protect the

produce, there are other requirements for a container:

• it should be easily transported when empty and occupy

less space than when full, e.g. plastic boxes which nest in each

other when empty, collapsible cardboard boxes, fi bre or paper

or plastic sacks;

• it must be easy to assemble, fi ll and close either by hand

or by use of a simple machine;

• it must provide adequate ventilation for contents during

transport and storage;

• its capacity should be suited to market demands;

• its dimensions and design must be suited to the available

transport in order to load neatly and fi rmly;

• it must be cost-effective in relation to the market value

of the commodity for which used;

• it must be readily available, preferably from more than

one supplier.

Packaging can be a major item of expense in produce

marketing, so the selection of suitable containers for commer-

cial-scale marketing requires careful consideration.

Besides providing a uniform-size package to protect the

produce, there are other requirements for a container:

• it should be easily transported when empty and occupy

less space than when full, e.g. plastic boxes which nest in each

other when empty, collapsible cardboard boxes, fi bre or paper

or plastic sacks;

• it must be easy to assemble, fi ll and close either by hand

or by use of a simple machine;

• it must provide adequate ventilation for contents during

transport and storage;

• its capacity should be suited to market demands;

• its dimensions and design must be suited to the available

transport in order to load neatly and fi rmly;

• it must be cost-effective in relation to the market value

of the commodity for which used;

• it must be readily available, preferably from more than

one supplier.