- Types Of Vegetables
- Allium Vegetables
- Buckwheat Family
- Composite Vegetables
- Cruciferous and Brassica Vegetables
- Goosefoot / Amaranth Vegetables
- Gourd Family
- Grass Family Vegetables
- Mallow Vegetables
- Morning Glory Vegetables
- Nightshade Vegetables
- Umbelliferous Vegetables
- Related books
- What are the most healthful vegetables?
- 13. Bell peppers
- 14. Cauliflower
- 15. Seaweed
- Different Types of Vegetables
- Tips for Managing Garden Produce
- Storing Fresh Vegetables
- Proper Refrigeration
- Packing Fresh Vegetables
- Freezing Fresh Vegetables
- Canning Fresh Vegetables
- Succession Planting To Manage Harvest Times
- Want to learn more about storing fresh garden vegetables?
- Cold Storage for Fruit and Veg
- The benefits of using commercial refrigeration to store fruits and vegetables
- Optimum storage temperatures for common fruits and vegetables
- What types of cold storage are suitable for fruit and vegetables?
- Best practices for storing fruit and vegetables
- Proper post-harvest cooling can:
- What to consider
- Managing temperature
- Heat load calculations
- Keys to designing a cold storage facility
Types Of Vegetables
Here’s an overview of the types of vegetables according to their family relationships. Related vegetables may seem dissimilar due to use of different parts of the plant, such as its stalk, leaves, or fruit.
Closely related vegetables typically have similarities in taste and nutrition, although some will be unique within their family. What is a food family?
The following types of vegetables can have unique properties, but each of these healthy vegetables gives you the excellent health benefits of vegetables.
For other types of foods, see the list of fruits, list of grains, list of nuts and seeds, and list of meats and poultry.
Vegetables in the onion family are anti-allergy, antioxidant, anti-cancer, anti-histamine, anti-inflammatory, antibacterial, antifungal, and antiviral!
(genus: Allium in the Allioideae subfamily of the Amarylidaceae family)
Asparagus is diuretic, detoxifying, and contains antioxidants.
Buckwheat is the basis for soba noodles and for kasha (roasted buckwheat groats). It is unreleated to wheat. Its surprising relative, rhubarb, has toxic leaves but its stalks are used for pies and jam.
Many of our salad greens are in the Composite family.
Curly endive / frisée
Cruciferous and Brassica Vegetables
Cruciferous vegetables, especially the Brassica genus, are the cancer-fighting vegetables.
Read more on Brassica vegetables
(genus: Brassica in the family Cruciferae or Brassicaceae)
Chinese cabbage (Napa cabbage)
Rapeseed oil (canola)
Other Cruciferous Vegetables
(family: Cruciferae or Brassicaceae)
Goosefoot / Amaranth Vegetables
The Goosefoot family includes detoxifying roots (beets), seeds used as alternative grains (amaranth and quinoa) and highly nutritious greens.
(family: Amaranthaceae / Chenopodiacae)
In this nutritious family, the colorful squash and melons contain important carotenoids.
Grass Family Vegetables
Grains such as wheat, rice, and corn are in the Grass family, and so are several vegetable and herb forms of these plants. For the grain forms, such as wheat and rice, see the list of grains.
Beans and the legume family are high in protein and fiber.
Okra is a unique and healthy vegetable used in Southern cooking. Cacao pods contain the “beans” (seeds of the fruit) that are the source of chocolate.
Morning Glory Vegetables
The sweet potato is a complex carbohydrate, and its orange flesh contains carotenoids and fiber. It is not related to the potato or to the true yam.
The good: colorful nightshade vegetables contain vitamin C and important antioxidants such as lycopene and lutein (and are fun vegetables).
The bad: nightshade vegetables also contain drug-like chemicals called glycoalkaloids. (Nicotine, the glycoalkaloid in tobacco, is one example.) Glycoalkaloids cause joint and muscle pain in some people.
More information on nightshade vegetables
Bell pepper (sweet pepper)
Chile pepper (examples of varieties):
- Pimiento / Pimento
Chili powder (some ingredients of)
Curry (some ingredients of)
Goldenberry (Cape gooseberry)
Fiber and phytochemicals combine in carrots, celery, and other umbelliferous vegetables.
Vegetables from Amaranth to Zucchini
Colorful reference book of vegetables.
Field Guide to Produce
How to identify, select, clean, and store produce.
Raw Food made Easy for 1 or 2 People
Easy raw food.
Vegetables Every Day
Beginner’s encyclopedia of vegetables.
- Healthy Eating
- Types of Vegetables
What are the most healthful vegetables?
Animal studies have suggested that alfalfa sprouts may have antioxidant effects and may reduce inflammation.
Eating sprouted legumes may have extra health benefits. Studies suggest that sprouting, or germinating, seeds increase their protein and amino acid content.
Germination may also improve the digestibility of alfalfa and other seeds and increase dietary fiber content.
How to eat alfalfa sprouts
Alfalfa sprouts are best enjoyed in salads and sandwiches.
13. Bell peppers
Share on PinterestBell peppers are popular as a raw or cooked ingredient.
Sweet bell peppers are commonly available in red, yellow, or orange varieties. Unripe, green peppers are also popular, but these taste less sweet than other colors.
A cup of chopped red bell peppers provides:
- 39 calories
- 190 milligrams of vitamin C
- 0.434 milligrams of vitamin B-6
- beta-carotene, which the body converts into vitamin A
Antioxidants present in bell peppers include capsanthin, quercetin, and lutein (in the green variety), which protects vision.
How to eat bell peppers
Bell peppers are extremely versatile. Add them to spaghetti dishes, scrambled eggs, or sandwiches, or serve them raw with a guacamole or hummus dip.
One cup of chopped cauliflower contains:
- 27 calories
- plenty of vitamin C
- vitamin K
Dietary fiber boosts a person’s heart and gut health, preventing digestive issues and reducing obesity.
Cauliflower and other cruciferous vegetables contain an antioxidant called indole-3-carbinol (I3C). I3C may reduce cancers of the breast and reproductive systems in both men and women.
Much like broccoli, cauliflower contains another potential anticancer compound: sulforaphane.
How to eat cauliflower
Pulse raw cauliflower in a blender to make cauliflower rice or turn it into a pizza base for a low-calorie, comforting treat. Alternatively, people may enjoy cauliflower in curries, or they may bake it with olive oil and garlic.
Seaweed, also known as sea vegetables, are versatile and nutritious plants that provide several health benefits. Common types of seaweed include:
- sea lettuce
Seaweed is one of the few plant-based sources of omega-3 fatty acids docosahexaenoic acid and eicosapentaenoic acid. These fatty acids are essential for a person’s health and are mostly present in meat and dairy sources.
Each type of seaweed has a slightly different nutritional profile, but it is typically rich in iodine, which is an essential nutrient for thyroid function.
Eating a variety of sea vegetables provides people with several important antioxidants to reduce damage to the body’s cells. Many types of seaweed contain chlorophyll, which is a plant pigment that has anti-inflammatory properties.
Brown sea vegetables, such as kelp and wakame, contain another potent antioxidant called fucoxanthin. Research suggests that fucoxanthin has 13.5 times the antioxidant power of vitamin E.
How to eat seaweed
Where possible, choose organic seaweed and eat it in small amounts to avoid introducing excess iodine to the diet. Enjoy sea vegetables in sushi, miso soups, and as a seasoning for other dishes.
Eating vegetables every day is important for health. They provide essential vitamins, minerals, and other nutrients, such as antioxidants and fiber.
Research consistently shows that people who eat the most vegetables have the lowest risk of many diseases, including cancer and heart disease.
Enjoy a range of vegetables daily to reap as many health benefits as possible.
Different Types of Vegetables
Vegetables form an important part of our daily diet; the market is crammed with varieties of vegetables. Veggies are naturally good and contain lots of minerals and vitamins. They help in protecting our body against cancers, diabetes and heart diseases. Almost all the vegetables are low in fat and calories, none have cholesterol and many of them are great sources of fiber. The high levels of fiber in vegetables keep the digestive system healthier; allowing you to avoid issues with constipation. Since veggies are low on calories, it enables us to eat lots of vegetables without consuming excess energy. The presence of many vitamins and other substance in vegetables provide nutrients to the body. Vegetables provide essential amino acids which are required by the body for survival. A simple meal of spinach, beans, and whole grain rice is a great way to treat your body right. This gives us the energy to become more active and helps us produce more energy each day. Go through this article and understand the different categories of vegetables.
Bulb vegetables are aromatic vegetables which are used widely to add flavour to casseroles, broths, courts-bouillons and soups. Garlic, chive, spring onion, water chestnut, grey shallot and other varieties of onions and leeks come under the category of bulb vegetables. They derived the name because it is the bulbs that are eaten, not the leaves. Some of the bulb vegetables including garlic are known for their medicinal value and recent studies suggest that some of these help in preventing cancer. While buying them, look for those that are unblemished and free of mould or dark spots. These vegetables can also be stored for a longer duration of time.
The harvest is payoff time for the gardener and farmer. It’s when all the work comes to fruition. The most intensive time in a gardener’s season, however, is just beginning when harvest comes. Bringing in the garden’s bounty and storing it takes a a lot of work.
Tips for Managing Garden Produce
Best practices for storing produce, but for the short and longterm, will ensure minimal losses during this hectic time of year. Properly packing, storing, and managing your harvest will mean an abundance of good food for a long time. Check out these tips below on how to preserve your harvest. Make sure you use safe practices for food storage in your kitchen. There’s a link at the bottom of the article for more information with special attention to the crop that is being preserved.
Storing Fresh Vegetables
Taking care of your vegetables from picking to storing is all about doing the job right so your efforts in growing that great bounty aren’t wasted. Clean and dry all vegetables carefully, being sure not to break the skin with scrubbing or scraping. Use clean water (no soap) and wipe away the dirt. Then lay out to dry on towels or blankets.
Most intact (uncut) vegetables can be refrigerated as they are. Filling crisper or salad drawers or bowls put onto refrigerator shelves is enough. Some leafy greens like lettuce and spinach should be stored in cloth bags that can be closed. Most vegetables will do well in refrigeration for a week or so. The longer they are in there, however, the more nutrients they’ll potentially lose, so your longer-term plans for storage should be quickly underway.
Packing Fresh Vegetables
Some vegetables can be packed and stored for a long time without anything more than a temperature-controlled area. Until recently, it was common to clutch root vegetables like potatoes at the center of mounds of dirt, which insulated them through the harshest weather.
Today, most people store their potatoes, thick-skinned squash, onions, etc. in root cellars or cool, dry larders. Some veggies need specific care to be stored this way, but so long as the temperature is held at 60-65 degrees Fahrenheit (for most), they will store for several months and stay fresh.
Root cellar and similar stored vegetables should be packed carefully to avoid bruising and should not be so deeply or heavily packed that their own weight crushes them.
Freezing Fresh Vegetables
Storing vegetables ready-to-use in the freezer is another popular method for long-term storage. The vegetables are usually prepared (green beans cut, spinach boiled, etc.) and blanched (quickly boiled and then cooled under water) to make them easier to use when the time comes, to lessen their volume for storage, and to eliminate microbes that could cause spoilage.
Vegetables to be frozen should be flash frozen if possible. Turn the freezer down to -10 degrees Farenheit a day or two before processing your vegetables and leave it that way until a day or two after the vegetables have been put in for freezing. Avoid overloading your freezer by putting too many unfrozen vegetables into it at one time.
Most people prefer freezer bags or stacked, sealed containers. Bags should be flattened and drained of air before sealing. Both types of container should be clearly labeled with the vegetable type and the date of freezing.
Canning Fresh Vegetables
The time-honored method of canning or jarring vegetables is another great way to preserve the harvest for the long-term. Of all the methods listed here, this one will last the longest (usually 2 or more years for most veggies, many much longer).
Canning is simply preparing the vegetables for the jar, adding water and (possibly) a preservative like vinegar or lemon oil, and boiling to both remove contaminates and cause the jar to seal when it returns to room temperature.
This can be a fun, family activity and requires only inexpensive tools to accomplish. It is, however, fairly labor intensive compared to other methods already listed.
Succession Planting To Manage Harvest Times
The easiest way to deal with a relatively large garden is to plant successively. This means planting vegetables in such a way to as time their harvest so that they can be picked over time rather than all at once.
This way, beets and carrots will be ready at the same time, but tomatoes and beans won’t be harvested until a week or two later. This can spread the harvest over a month or even six weeks, saving a lot of hectic effort for the gardener.
Want to learn more about storing fresh garden vegetables?
Guide to Storing Fresh Vegetables from University of Idaho Extension
- Cabbages – Harvest cabbages when the heads feel firm and full. Remove outside leaves. Cabbages like a high humidity and can be stored in perforated plastic bags. Any plastic bag will do if you punch some hole in it for excess water to escape.
- Onions and Garlic – Dig onions when the tops fall over and allow them to dry in a warm, well-ventilated spot. When the tops are fully dry, cut them down to about 1 in. Let them continue drying for another 1 – 2 weeks. The skins should be papery and flaky. Store in a dry spot that stays just above freezing. The biggest reasons onions do not store well are if they are not fully dried before storage or if they are exposed to warm temperatures and light. Onions with wide necks or green stalks will not store long.
You can braid and hang onions to dry, but as they do, the braids will become brittle and will start braking.
Garlic dries and stores in a similar way. Softneck varieties will keep the longest, usually about 6 – 8 months. Hardnecks should be used within 4 months
- Potatoes – Harvest potatoes when their tops begin to die back. Dig and brush off as much soil as possible. Allow them to dry, in a cool, well-ventilated spot. They are ready to store when the skin does not peel off with the pressure of your thumb.
- Root Vegetables (beets, carrots, parsnips, rutabagas, salsify) – Dig root vegetables when they have reached the desired size for the particular variety. Most root vegetables are sweeter if you wait until they have been exposed to a frost. Once harvested, remove all but ½ in. of the tops. This little bit of top growth will seal in juices and seal out problems. You can also remove the tap root that extends below the edible root, but it is not necessary.
Root vegetables can be prone to shriveling. Storing them in slightly damp sphagnum moss or plastic bags with a few holes punched in them will help hold in moisture.
You can keep carrots and parsnips in the ground all winter, but you won’t be able to harvest them once the ground freezes.
- Winter Squash and Pumpkins – Make sure these are fully ripened, with a rind hard enough to resist being dented with your nail. Leave a couple of inches of stem intact and do not use it as a handle, or you could injure the squash. Allow to cure in a warm, dry, well-ventilated spot for about 10 – 14 days, then store in a cool, dark, dry spot where you can spread them out and keep them separate. (Note: acorn squash stores better if not cured beforehand.)
Cold Storage for Fruit and Veg
Cold storage for fruit and veg is a particularly tricky subject as there are many factors, such as age and origin, which can affect how fresh produce should be stored. This guide looks at why you should be using cold storage to stock and distribute your fresh produce and the most important factors to consider when using cold storage for fruit and veg.
The benefits of using commercial refrigeration to store fruits and vegetables
Without cold storage, most fruits and vegetables will not stay fresh for more than a few days. As soon as fresh produce is harvested, it begins to deteriorate and dangerous bacteria will start to develop.
The low temperatures inside cold storage units halt the growth of these pathogenic fungi, ensuring that spoilage of fruits and vegetables is kept to a minimum. Refrigeration and blast freezing are equally popular options for many vegetables and some selected fruits. This is why our cold storage units have a varied temperature range for both freezing and chilling options.
Another ingenious benefit of cold storage units is that they are highly customisable, something that is particularly important when storing fresh fruits and vegetables. Temperature and humidity levels can vary greatly between produce, making customisation essential. Cold storage for fruit and veg also comes in a variety of sizes, including mini chillers that are perfect for caterers and mega cold stores made with large distributors in mind.
Whether you’re looking to extend your commercial refrigeration or are considering branching out into the fruit and veg market, a portable cold storage solution will extend the life of your fruits and vegetables both in storage and in transit.
Optimum storage temperatures for common fruits and vegetables
There is rarely a one temperature fits all solution to storing fruit and veg. This is because factors such as crop maturity, the season of harvest and crop origins all play a part in calculating the optimum temperature requirements.
A general ‘rule of thumb’ is that cool season fruit and veg, such as kale and sprouts, should be stored at around 0-2°C. Warmer season fruit and veg, such a cucumber and tomato, is best stored around 7-10°C. However, there are exceptions to the rule, as some fruit and veg is more greatly affected by low temperatures.
This table is a guideline for storing some of the most common/popular types of fruit and veg.
Optimum Temperature °C
Optimum humidity %
Up to 12 months
Up to 3 weeks
Berries (incl. Strawberries)
Blackberries and raspberries up to 3 days, strawberries and cherries up to 7 days
Up to 8 weeks
Nectarines, plums and peaches
Up to 5 weeks
Up to 7 months
Broccoli and cauliflower
Up to 4 weeks
Carrots, mature and immature
Mature, up to 9 months and immature up to 6 weeks
Onion, white and red
Up to 8 months
Up to 3 weeks
All cold store refrigeration units will provide you with a temperature range between -40°C to +10°C, making them perfect for the storage of fruits and vegetables.
What types of cold storage are suitable for fruit and vegetables?
Most cold storage is incredibly versatile, meaning that there are plenty of options when it comes to storing and distributing fruit and veg.
CRS refrigerated containers come in a variety of sizes from 10ft to 45ft and have a temperature range of -40°C to +10°C. Most cold store units are portable and can be used to safely transport goods. Mega cold stores are also a popular option for larger companies and work by combining multiple linked cold store units for a mega refrigerated solution.
Blast freezers and chillers
For businesses looking to stock and distribute frozen fruit and veg, rapid freezing blast chillers are a great option. With temperatures as low as -40°C, you can freeze a variety of fruits and vegetables. Mini blast freezers are also available for caterers or smaller businesses short on space.
Grade A specification cold rooms are ideal for use as both hygienic food processing areas and for fresh produce storage. Cold rooms are a great solution for any business looking for custom cold storage for their fruit or veg.
Best practices for storing fruit and vegetables
As you can see, the storage of fruits and vegetables can be a complicated task, which is why adhering to cold storage best practices is essential for the longevity and quality of your fruit and veg.
What are the best practices for fruit and vegetable storage?
Fruit and veg should always be stored separately
Most fruits produce a hormone called ethylene once they begin to ripen and this changes texture, colour and flavour in produce. Unfortunately, fruits producing ethylene also affect all surrounding produce, speeding up the ripening process considerably. If fruits are stored alongside vegetables, you risk speeding up the ageing process of produce, resulting in food wastage.
Adhere to good storage practices
Avoid overstocking your cold storage unit above its capacity, as this raises the internal temperature and speeds up produce deterioration. Tightly packed pallets should also be avoided as crushing can occur, leading to the development of bacterial growth. Pack your fruit and veg so that there is enough room for the internal fan to distribute cool air freely.
Know the history of your produce
Distributors should know the history of fruit and veg to make the best decision regarding cold storage and transportation arrangements. This includes factors such as product maturity, prior goods preparation, previous quality inspections and produce grading.
Whilst cold storage can increase the longevity of your fruits and vegetables, your produce still needs some TLC to keep it at its best. Look after your fruit and veg and you’ll extend its lifespan considerably.
If you’re looking for quality cold storage for fruit and veg, contact CRS today on 0800 085 2298. Alternatively, contact us online or to see out range of suitable cold storage options.
Care should be taken to store only, those kinds, which does not show in compatibility of storage, when storing multi-produce in the same room. For example, apple can be stored with grapes, oranges, peaches, and plums and not with banana. However, with potato and cabbage slight danger of cross actions can occur. Contrary to this, grape in compatible to all other vegetables except cabbage. To resolve the incompatibility during cold storage, foodstuffs are grouped into three temperature ranges
Based on their thermal incompatibility the produce is classified into:
Most perishable products, not sensitive to cold (0-4°C)
e.g. Apple, grape, carrot and onion
Vegetable produce moderately sensitive to cold (4-8°C)
e.g. Mango, orange, potato and tomato (ripened)
Vegetable produce sensitive to cold (>8°C)
e.g. Pineapple, banana, pumpkin and lady finger
Based on the purpose, the present day cold stores are classified into following groups:
Bulk cold stores: Generally, for storage of a single commodity which mostly operates on a seasonal basis e.g.: stores for potatoes, chilies, apples etc.
Multi-purpose cold stores: It is designed for storage of variety of commodities, which operate practically, throughout the year.
Small cold stores: It is designed with pre-cooling facilities. For fresh fruits and vegetables, mainly for export-oriented items like grapes etc.
Frozen food stores: It is designed for with (or) without processing and freezing facilities for fish, meat, poultry, dairy products and processed fruits and vegetables.
Mini units or walk in cold stores: It is located at distribution center etc.
Controlled atmosphere (CA) stores: It is mainly designed for certain fruits and vegetables
General Arrangements and Consideration
If produce is to be stored, it is important to begin with a high quality product. The produce must not contain damaged or diseased units, and containers must be well ventilated and strong enough to withstand stacking. In general, proper storage practices include temperature control, relative humidity control, air circulation and maintenance of space between containers for adequate ventilation and avoiding incompatible product mixes. Commodities stored together should be capable of tolerating the same temperature, relative humidity and level of ethylene in the storage environment. High ethylene producers (such as ripe bananas and apples) can stimulate physiological changes in ethylene sensitive commodities (such as lettuce, cucumbers, carrots, potatoes, sweet potatoes) leading to often undesirable color, flavour and texture changes.
The general features of a cold store operational programme (products, chilling and chilled storage and freezing) include total capacity, number and size of rooms, refrigeration system, storage and handling equipment and access facilities. The relative positioning of the different parts will condition the refrigeration system chosen. The site of the cold chambers should be decided once the sizes are known, but as a general rule they should be in the shade of direct sunlight. The land area must be large enough for the store, its annexes and areas for traffic, parking and possible future enlargement. A land area about six to ten times the area of the covered surface will suffice.
There is a general trend to construct single-storey cold stores, in spite of the relatively high surface: volume ratio influencing heat losses. The single storey has many advantages: lighter construction; span and pillar height can be increased; building on lower resistance soils is possible; internal mechanical transport is easier. Mechanical handling with forklift trucks allows the building of stores of great height, reducing the costs of construction for a given total volume.
The greater the height of the chambers the better, limited only by the mechanical means of stacking and by the mechanical resistance either of the packaging material or of the unpackaged merchandise. The length and width of the chambers are determined by the total amount of merchandise to be handled, how it is handled (rails, forklift trucks), the number of chambers and the dimensions of basic handling elements. There is no advantage in building many chambers of a small size. Thermal and hygrometric requirements are not so strict as to justify a lot of rooms: the accuracy of the measuring instruments and the regulation of conditions inside the chamber always produce higher deviations than those of ideal storage conditions for different products. This is particularly true for frozen products.
A design that opts for fewer, larger chambers represents in the first place an economy in construction costs as many divisional walls and doors are eliminated. Refrigeration and control equipment is simplified and reduced, affecting investment and running costs. Large chambers allow easier control of temperature and relative humidity and also better use of storage space. Only in very particular situations should the cold store be designed with more than five or six cold chambers. Store capacity is the total amount of produce to be stored. If the total volume of the chambers is filled, the quantity of produce by unit of volume will express storage density.
Several parameters must be defined within a cold store. The total volume is the space comprised within the floor, roof and walls of the building. The gross volume is the total volume in which produce can be stored, that is excluding other spaces not for storage. The net volume represents the space where produce is stacked, excluding those spaces occupied by pillars, coolers, ducts, air circulation and traffic passages inside the chambers that are included in the gross volume. Storage density referred to as net volume is expressed in kg/m3. But it is most commonly referred to as gross volume. About 3.4 m3 of volume is required per ton of potato to be preserved while for onions this value is about 5.7 m3/t. Thus, one can calculate the total volume of storage space as soon as the amount of storage product is known. An index of how reasonably and economically the cold store has been designed is the gross volume divided by the total volume. It must be in the range of 0.50 to 0.80. Similarly, gross volume is about 50 per cent greater than net volume, and gross area (same concept as volume) is about 25 per cent greater than net area. The extent of occupation is the ratio between the actual quantity of produce in storage at a given moment and that which can be stored. Equally the extent of utilisation is the average of the extent of occupation during a given period — usually a year, but it can also be per month.
The earlier cold storage were cubical in shape in order to minimize the surface area for a given
volume, i.e., a = b = H = V1/3
Where a, b, H and V are width, breadth, height and volume of storage space. In doing so the height of large cold storage becomes too big, causing material handling, stacking and similar other problems. A comparative study of the single and multi-storeyed cold store buildings has been made with respect to space and installation (Heinze, 1973). It has been found that the single-storeyed buildings turn out to be a better choice. However, the multi-storeyed cold storages with mechanised arrangements are preferred for the multi-variety systems, especially, in cities where the floor area is extremely expensive. Sometimes cold storage size is based on floor area, i.e., about 100 kg m2. However, there does not exist a unique specification agreed upon and used internationally. Despite lots of discussions differences on specification on the cold storages exist.
Temperature management during storage can be aided by constructing square rather than rectangular buildings. Rectangular buildings have more wall area per square meter of storage space, so more heat is conducted across the walls, making them more expensive to cool. Temperature management can also be aided by shading buildings, painting storehouses white or silver to help reflect the sun’s rays, or by using sprinkler systems on the roof of a building for evaporative cooling. Facilities located at higher altitudes can be effective, since air temperature decreases as altitude increases. Increased altitude therefore can make evaporative cooling, night cooling and radiant cooling more feasible. The air composition in the storage environment can be manipulated by increasing or decreasing the rate of ventilation (introduction of fresh air) or by using gas absorbers such as potassium permanganate or activated charcoal. Large-scale controlled or modified atmosphere storage requires complex technology and management skills; however, some simple methods are available for handling small volumes of produce.
Heat Load Calculations
The optimal storage temperature must be continuously maintained to obtain the full benefit of cold storage. To make sure the storage room can be kept at the desired temperature, calculation of the required refrigeration capacity should be done using the most severe conditions expected during operation. These conditions include the mean maximum outside temperature, the maximum amount of produce cooled each day, and the maximum temperature of the produce to be cooled. The total amount of heat that the refrigeration system must remove from the cooling room is called the heat load. If the refrigeration system can be thought of as a heat pump, the refrigerated room can be thought of as a boat leaking in several places with an occasional wave splashing over the side. The leaks and splashes of heat entering a cooling room come from several sources:
- Heat Conduction – Heat entering through the insulated walls, ceiling, and floor;
- Field Heat – Heat extracted from the produce as it cools to the storage temperature;
- Heat of Respiration – Heat generated by the produce as a natural by-product of its respiration;
- Service Load – Heat from lights, equipment, people, and warm, moist air entering through cracks or through the door when opened.
Fundamentals for Designing a Cold Storage Project
The design of cold storage facilities is usually directed to provide for the storage of perishable commodities at selected temperature with consideration being given to a proper balance between initial, operating, maintenance, and depreciation costs. The basic procedures for constructing (or) implementing the cold store units have the following requirements:
The most important requirement for any food project using insulated envelopes is to determine the process layout of the operation which is to be housed by the envelope. In the case of a meat plant, this can be a carcass dressing line or a boning room, or for a cold store, the pallet layout and mode of operation must be established. It is simply no good building an envelope and then attempting to place the processing machinery inside it.
Planning Drawings and Application
It is only after concluding the process layout that a planning application can be made when the dimensions of the envelope and supporting buildings can be frozen.
Design Drawings and Specifications
Once planning approval has been obtained then the preparation of design drawings and specifications can proceed. For a competitive design and construct tender, it is essential to prepare some 15 – 20 detailed drawings covering, at the minimum, the process layout, elevations and sections, the refrigeration system layout, mechanical and electrical systems reticulation and the lighting layout.
In addition to make up package at least six separate detailed specifications are required covering the project’s requirements on:
- Contractual requirements
- Building specification
- Refrigeration specification
- Insulation panel supply and erection
- Electrical requirements
- Mechanical services.
The location chosen for the cooling facility should reflect its primary function. If the plan is to conduct retail sales of fresh produce from the facility, it should be located with easy access to public roads. A retail sales operation located away from the road, particularly behind dwellings or other buildings, discourages many customers. Adequate parking for customers and employees, if any, must be provided.
If, however, the primary function of the cooling facility is to cool and assemble wholesale lots, ease of public access is less important. In this case, the best location may be adjacent to the packing or grading room. In addition to housing grading and packing equipment, the space could be used to store empty containers and other equipment and supplies when it is not needed for cooling. All cooling and packing facilities should have convenient access to fields or orchards to reduce the time from harvest to the start of cooling.
Regardless of how it is used, the facility will need access to electrical power and water. For larger cooling rooms requiring more than about 10 tons of refrigeration in a single unit, access to three-phase power will be necessary. The location of existing utility lines should be carefully considered, as connection costs can be prohibitive in some rural areas. Consult local power company for details.
In addition, it is a good idea to anticipate any future growth when locating and designing your facility. The cold storage unit should be built on a site, a where the ground in clean, well drained and preferably leveled and near to supplies of energy and water. If possible, it should be in the shade of prevailing wind and direct sunlight. A refrigerated store, with one (or) more thermally insulated places, and refrigerating machines can be planned with the aim of assuring certain services. The details about :
- Nature of the products
- Frequency of loading and unloading
- Calendar for harvest and dispatch
- Field heat of the produce
- Daily tonnage of produce to be handled
- Daily tonnage of ice to be manufactured
- Nature and dimension of packages
The above particulars are to be collected before initiating the cold storage unit work. The conditions to be considered for planning, a cold storage are temperature and duration of storage, handling and stacking method, type of; commodities to be stored together, prevailing climatic factors like temperature, relative humidity, rainfall, wind and water. Availability of skilled and unskilled labor from the local area is the major factor to be considered for the successful operation.
By Mahesh Kumar, BVC Mahajan
Cold storage is the one widely practised method for bulk handling of the perishables between production and marketing process.
The optimal storage temperature must be continuously maintained to obtain the full benefit of cold storage. Image credit: Burgess Rawson
It is one of the methods of preserving perishable commodities in a fresh and wholesome state for a longer period by controlling temperature and humidity within the storage system. Maintaining adequately low temperature is critical, as otherwise it will cause chilling injury to the produce. Also, relative humidity of the storeroom should be kept as high as 85-90% for most of the perishables.
Most fruits and vegetables have a very limited life after harvest if held at ambient harvesting temperatures. Post-harvest cooling rapidly removes field heat, allowing longer storage periods.
Proper post-harvest cooling can:
- Reduce respiratory activity and degradation by enzymes;
- Reduce internal water loss and wilting;
- Slow or inhibit the growth of decay-producing microorganisms;
- Reduce the production of the natural ripening agent, ethylene.
In addition to helping maintain quality, post-harvest cooling also provides marketing flexibility by allowing the grower to sell produce at the most appropriate time. Having cooling and storage facilities makes it unnecessary to market the produce immediately after harvest. This can be an advantage to growers who supply restaurants and grocery stores or to small growers who want to assemble truckload lots for shipment. Post-harvest cooling is essential to delivering produce of the highest possible quality to the consumer. Cold storage can be combined with storage in an environment with addition of carbon dioxide, sulphur dioxide (in case of grapes) nitrogen, according to the nature of product to be preserved. The cold storage of dried/dehydrated vegetables can be successfully carried out for a storage time of more than one year, at 0°-10°C with a relative humidity of 80-95%.
The cold storage of perishables has advanced noticeably in recent years, leading to better maintenance of organoleptic qualities, reduced spoilage, and longer shelf lives.
Also read: How to improve cold-storage supply-chain management
Care should be taken to store only those things which do not show incompatibility of storage when storing multi-produce in the same room. For example, apples can be stored with grapes, oranges, peaches, and plums and not with bananas. However, with potato and cabbage, slight danger of cross actions can occur. Contrary to this, grapes are incompatible with all other vegetables except cabbage. To resolve the incompatibility during cold storage, foodstuffs are grouped into three temperature ranges.
- Most perishable products, not sensitive to cold (0-4°C)
e.g. Apple, grape, carrot and onion
- Vegetable produce moderately sensitive to cold (4-8°C)
e.g. Mango, orange, potato and tomato (ripened)
- Vegetable produce sensitive to cold (>8°C)
e.g. Pineapple, banana, pumpkin and okra
Based on the purpose, the present-day cold stores are classified into following groups:
- Bulk cold stores: Generally, for storage of a single commodity which mostly operates on a seasonal basis, for example, stores for potatoes, chillies and apples.
- Multi-purpose cold stores: It is designed for storage of variety of commodities, which operate practically throughout the year.
- Small cold stores: It is designed with pre-cooling facilities. For fresh fruits and vegetables, mainly for export-oriented items, like grapes.
- Frozen food stores: It is designed for with or without processing and freezing facilities for fish, meat, poultry, dairy products and processed fruits and vegetables.
- Mini units or walk in cold stores: It is located at distribution centre.
- Controlled atmosphere (CA) stores: It is mainly designed for certain fruits and vegetables.
What to consider
If produce is to be stored, it is important to begin with a high-quality product. The produce must not contain damaged or diseased units, and containers must be well ventilated and strong enough to withstand stacking. In general, proper storage practices include temperature control, relative humidity control, air circulation and maintenance of space between containers for adequate ventilation and avoiding incompatible product mixes.
The general features of a cold store operational programme (products, chilling and chilled storage and freezing) include total capacity, number and size of rooms, refrigeration system, storage and handling equipment and access facilities. The relative positioning of the different parts will condition the refrigeration system chosen.
Also read: Refrigerated Warehousing And Storage – Refrigerants Matter
There is a general trend to construct single-storey cold stores. The single storey has many advantages:
- Lighter construction;
- Span and pillar height can be increased;
- Building on lower resistance soils is possible;
- Internal mechanical transport is easier.
Several parameters must be defined within a cold store. The total volume is the space comprised within the floor, roof and walls of the building. The gross volume is the total volume in which produce can be stored that is excluding other spaces not for storage. The net volume represents the space where produce is stacked, excluding those spaces occupied by pillars, coolers, ducts, air circulation and traffic passages inside the chambers that are included in the gross volume. Storage density referred to as net volume is expressed in kg/m3 but is the most commonly referred to as gross volume. About 3.4m3 of volume is required per ton of potato to be preserved while for onions this value is about 5.7 m3/t.
An index of how reasonably and economically the cold store has been designed is the gross volume divided by the total volume. It must be in the range of 0.50 to 0.80. Similarly, gross volume is about 50% greater than net volume, and gross area (same concept as volume) is about 25% greater than net area. The extent of occupation is the ratio between the actual quantity of produce in storage at a given moment and that which can be stored. Equally the extent of utilisation is the average of the extent of occupation during a given period — usually a year, but it can also be per month.
Temperature management during storage can be aided by constructing square rather than rectangular buildings. Rectangular buildings have more wall area per square meter of storage space, so more heat is conducted across the walls, making them more expensive to cool.
Temperature management can also be aided by shading buildings, painting storehouses white or silver to help reflect the sun’s rays, or by using sprinkler systems on the roof of a building for evaporative cooling. Facilities located at higher altitudes can be effective, since air temperature decreases as altitude increases. Increased altitude, therefore, can make evaporative cooling, night cooling and radiant cooling more feasible.
Heat load calculations
The optimal storage temperature must be continuously maintained to obtain the full benefit of cold storage. To make sure the storage room can be kept at the desired temperature, calculation of the required refrigeration capacity should be done using the most severe conditions expected during operation. These conditions include the mean maximum outside temperature, the maximum amount of produce cooled each day, and the maximum temperature of the produce to be cooled. The total amount of heat that the refrigeration system must remove from the cooling room is called the heat load. If the refrigeration system can be thought of as a heat pump, the refrigerated room can be thought of as a boat leaking in several places with an occasional wave splashing over the side.
Keys to designing a cold storage facility
The design of cold storage facilities is usually directed to provide for the storage of perishable commodities at selected temperature with consideration being given to a proper balance between initial, operating, maintenance, and depreciation costs.