STRAWBERRY: for Swat. NUTRITIONAL VALUE: We know that

STRAWBERRY:

Strawberry is a non-climacteric fruit that usually takes up to 30 days to
achieve full size and maturity. This time is highly dependent on light,
temperature, soil composition, and other conditions of cultivation. Strawberries are
no exception to this rule; in addition to antioxidants, they have many other
nutrients, vitamins, and minerals that contribute to overall health. These
include folate, potassium, manganese, dietary fibre, and magnesium. It is also
extremely high in vitamin C.

Kingdom:

Plantae

(unranked):

Angiosperms

Order:

Rosales

Family:

Rosaceae

Subfamily:

Rosoideae

Genus:

Fragaria

Species:

ananassa

 

The
garden strawberry was first bred in
Brittany, France, in the 1750s via a cross of Fragaria virginiana from eastern North America and Fragaria chiloensis, which was brought
from Chile in 1714. Cultivars of Fragaria
× ananassa have replaced, in commercial production, the woodland strawberry
(Fragaria vesca), which was the first
strawberry species cultivated in the early 17th century.

The
strawberry is not, from a botanical point of view, a berry. Technically, it is
an aggregate accessory fruit, meaning that the fleshy part is derived not from
the plant’s ovaries but from the receptacle that holds the ovaries. Each
apparent “seed” (achene) on the outside of the fruit is one of the
ovaries of the flower, with a seed inside it

Since
2006, 74 new strawberry plant cultivars have been released in the United
States. This research is a portion of a larger U.S. Department of
Agriculture-funded project called ”RosBREED:
Enabling marker-assisted breeding in Rosaceae.” The overall goal of RosBREED
is to facilitate the use of DNA marker-assisted breeding in Rosaceae fruit
crops to improve.

VARIETIES OF STRAWBERRY:

Fragaria vesca
for wild strawberry, and Fragaria
orientalis for strawberries found in Siberia. Strawberries grow in bushes
and are delicious seasonal fruits that also boost your health. Strawberries are
often associated as a European fruit; however, they are popular throughout the
world. Since 1988 to 1998, many new varities of strawberries
have being released for improved fruit quality which includes Ciflorette in 1998, Cirafine in 2001 and Charlotte in 2004.

In
Pakistan strawberry is consumed in
fresh form as well as in processed form for making squashes, jams and jellies
which may use throughout the year. Main varieties of strawberry which are
cultivated in Pakistan are Douglas and Toro appropriate for southern areas of
Pakistan whereas Chandler, Cruz Pocahontas and Tufts are suitable for Islamabad
and Honeyo, Chandler, Gorella and Corona are recommended for Swat.

NUTRITIONAL VALUE:

We know that fruits, particularly berries and those
with exotic colors are rich in antioxidants, which means that they are huge
boosters to your health. Strawberries are no exception to this rule; in
addition to antioxidants and polyphenols, they have many other nutrients,
vitamins, and minerals that contribute to the overall health benefits of these
berries. These nutrients include vitamin C, folate, potassium, manganese,
dietary fibre, and magnesium.

Energy

136 kJ

Water

91 %

Protein

0.7 g

Sugar

4.9 g

Fiber

2 g

Fat                 

0.3 g

Saturated      

0.02 g

Monounsaturated

0.04 g

Polyunsaturated

0.16 g

        

             NUTRITIONAL
VALUE: STRAWBERRIES, RAW – 100 GRAMS

BENEFITS:

1.     
Strawberries are helpful because they contain
potassium, which helps in maintaining the correct ocular pressure. Ocular
pressure means the pressure within the eyes. Any disturbance in this pressure
can be harmful to the eyes.

2.     
Vitamin C present in strawberry boosts the immune
system and helping in curing common cough and cold.

3.     
A single serving of strawberries has approximately 150%
of your daily requirement of vitamin C.

4.     
It is said that a serving of fruits every day will
remove the “rust” from joints. Strawberries are abundant in antioxidants and
detoxifiers, which help in treating primary causes of arthritis and gout.

5.     
Vitamin-C, folate, anthocyanins, quercetin, and
kaempferol are just a few of the many flavonoids in strawberries which possess
excellent antioxidant and anticarcinogenic properties. Together, they form an
excellent line of defense to fight cancer and tumor growth. Daily intake of
strawberries is connected to a drastic reduction in the presence and metastasis
of cancer cells.

6.     
Strawberries are rich in iodine as well, which is very
helpful for regulating the proper functioning of the brain and nervous system.

7.     
Potassium, is a vasodilator, meaning that it reduces
hypertension and the rigidity of arteries and blood vessels which is found in
significant quantities in strawberries, also has been linked to improved
cognitive function by increasing the blood flow to the brain.

8.     
Strawberry promotes weight loss due to the presence of
various nutrients that help to stimulate metabolism and reduce appetite.

9.     
High fiber content, folate, no fats, and high levels of
antioxidants such as vitamin-C and phytochemicals form an ideal cardiac health
pack, as they effectively reduce cholesterol in the arteries and vessels. Some
members of the vitamin-B family present in strawberries also strengthen the
cardiac muscles and lead to better functioning of the heart.

10.  Strawberries
are rich in potassium and magnesium content, both of which are effective in
lowering high blood pressure caused by sodium and various other risk factors.

 

ALLERGY:

Some people experience an anaphylactoid reaction to
eating strawberries. The most common form of this reaction is oral allergy
syndrome, but symptoms may also mimic hay fever or include dermatitis or hives,
and, in severe cases, may cause breathing problems. Proteomic studies indicate
that the allergen may be tied to a protein for the red anthocyanin biosynthesis
expressed in strawberry ripening, named Fra
a1 (Fragaria allergen1). Homologous proteins are found in birch pollen and
apple, suggesting that people may develop cross-reactivity to all three
species.

White-fruited strawberry cultivars, lacking Fra a1,
may be an option for strawberry allergy sufferers. Since they lack a protein
necessary for normal ripening by anthocyanin synthesis of red pigments, they do
not turn the mature berries of another cultivars red. They ripen but remain
white, pale yellow or “golden”, appearing like immature berries; this also has
the advantage of making them less attractive to birds. A virtually
allergen-free cultivar named ‘Sofar’ is available.

GENETICS:

Strawberry plants have unique diversity when it comes
to their genetic makeup.  Strawberry plant species have varying numbers of
chromosomes. Official number of chromosomes is 7.
Normally strawberries would have 14 chromosomes (2n), to
make larger berries, 8 duplicate copies of the genome (8n known as octaploids). It sequenced
to display 7,096 genes.

Strawberries
suffer from severe inbreeding depression, and most cultivars are highly
heterozygous. Most species are diploid, meaning they have two sets of
chromosomes, one set of chromosomes is normally inherited from each
parent.  Polyploidy, a condition more common in plants, occurs when
multiple pairs of chromosomes are present in the genetic component of an
organism.  Strawberry species and
hybrids can be diploid, tetraploid, pentaploid, hexaploid, heptaploid,
octoploid, or decaploid (having 2, 4, 5, 6, 7, 8, or 10 sets of the seven
strawberry chromosomes, respectively).  Strawberries have many different chromosome
numbers. While these are four of the most common numbers of chromosome pairs
some strawberries can have as many as 16.

Following
are some species along with their natives:

Diploid:

Fragaria daltoniana — native to Asia

Fragaria nilgerrensis — native to South Asia

Fragaria nubicola — native to South Asia

Fragaria vesca — found throughout Europe, North America,
and Northern Asia as well as North Africa, the mountains of South America, and
the northern polar region.

Fragaria viridis
— native to Central Europe

Tetraploid:

Fragaria moupinensis
— native to East Central Asia

Fragaria orientalis
— native to Northeast Asia

Hexaploid:

Fragaria moschata
— native to Central Europe

Octaploid:

Fragaria chiloensis
— native to South Chile, mountains of Hawaii

Fragaria ovalis
— native to Western North America

Fragaria virginiana
— native to Eastern North America

PRODUCTION:

California and Florida are the top
two strawberry producing states within the U.S., with California producing over
91 percent of the entire strawberry crop. Florida, however, produces most of
the domestic winter strawberry crop. Over 4.3 million tonnes of
strawberries are produced each year. This has increased from 3.2 million tonnes
over the last decade. Biggest producer is the USA at 1.3 million tonnes per annum
– which represents 30% of the world’s crop. Second one is Turkey with 302,416
tons and Spain in third place with 262,730 tons. Other top strawberry producing
countries in the world include Egypt, Mexico, Russia, Japan, South Korea,
Poland, and Germany. The areas grown and their respective yields vary
considerably, largely due to production methods.

In Pakistan, it is grown in northern areas like Swat,
Charsadda, Mansehra, Haripur, Abbottabad, Mardan, Peshawar and some parts of
central Pakistan. In Pakistan, it is grown on area of 78 hectares with annual
production of about 274 tonnes.

The average per acre yield is very low as compared to
other strawberry growing countries.

Quality
improvement:

                             As strawberry
flavor and fragrance are popular characteristics for consumers, they are used
widely in a variety of manufacturing, including foods, beverages, confections,
perfumes and cosmetics. Sweetness, fragrance and complex flavor are favorable
attributes. In plant breeding and farming, emphasis is placed on sugars, acids,
and volatile compounds, which improve the taste and fragrance of a ripe
strawberry. Esters, terpenes, and furans are chemical compounds having the
strongest relationships to strawberry flavor and fragrance, with a total of 31
volatile compounds significantly correlated to favorable flavor and fragrance.

Color:

Pelargonidin-3-glucoside is the major anthocyanin in
strawberries and cyanidin-3-glucoside is found in smaller proportions. Although
glucose seems to be the most common substituting sugar in strawberry
anthocyanins, rutinose, arabinose, and rhamnose conjugates have been found in
some strawberry cultivars. One of the pigments, cyanidin, that makes up the red
color in strawberries has a much higher antioxidant potential than others.

Fragrance:

Chemicals present in the fragrance of strawberries
include: ethyl acetate, ethyl benzoate, ethyl butyrate, amyl acetate, amyl
butyrate, benzaldehyde, benzyl acetate etc.

Perishability:

The fruit is highly perishable with a shelf life of
2–3 days at room temperature and is vulnerable to postharvest decay due to its
high respiration rate, environmental stresses and pathogenic attacks. Fresh
strawberries are highly perishable and cannot be stored except briefly. For
maximum life, perhaps of 5-7 days, fruit should be precooled immediately after
harvest and placed at 0°C. The temperature of harvested strawberries in the
field can get up to 30°, and higher when exposed to sun. Precooling of whole
pallets by forced air is recommended because the desired temperature (1°) can
be obtained with in 1 hour, whereas air cooling takes 9 hours.

After a few days in storage, the fruit loses some of
its fresh bright color, tends to shrivel, and deteriorates in flavor.
Deterioration is arrested by low temperature; but after removal from storage,
it proceeds more rapidly than in freshly picked strawberries. The major
diseases causing storage losses in strawberries are gray mold rot, Rhizopus
rot, and leather rot. Prompt precooling to temperatures of 5° or below and
holding at such temperatures in transit, storage, and during marketing will minimize
such losses.

Refrigeration is sometimes supplemented with carbon
dioxide gas from dry ice to modify the atmosphere during transit or storage. In
air transport, pallets are covered with curtain coated fiberboard or
heat-shrink polyethylene to retain the high level of carbon dioxide. High
levels of carbon dioxide (10 to 30 percent) slow the respiration rate of the
fruit and reduce the activity of decay-causing organisms, thus extending
storage and market life. Carbon dioxide atmospheres of 30 percent or greater
can cause off-flavor. Low-oxygen atmospheres of 0.5 to 2 percent will also
reduce respiration rate and decay, but the fruit develops off-flavor.
Postharvest chemical and heat treatments can be useful in reducing decay during
storage and handling. However, surface sheen can be lost when fruit are dipped
in water or solutions.

Breeding
techniques:

Traditional breeding:

                      Traditional breeding refers to the process
of allowing certain chosen plants to sexually reproduce with other plants.
Plants are chosen based on favorable characteristics. Simply put, traditional
breeding takes plants with favourable characteristics and breeds them. Then the
offspring are raised and then judgment is made about which ones have the best
traits and the process proceeds to the next generation. This method has been
the way that humans have traditionally modified organisms. Not until the 20th
century were humans able to influence the genotypes of organisms in any other
way e.g. the “Downton” was a successful variety developed by
Andrew Knight because of his 1817 breeding experiment. The mother of this
variety was a plant grown from seeds direct from America (probably F.
Virginiana) and its father was the variety “Old Black”, which is of
uncertain origin. This variety was created by pollination, not direct
manipulation of the plant’s genes.

Genetic engineering:

               Genetic
engineering is typically defined as the introduction of non-native genes into
an organism. An example of cold resistance: An excellent example of
transgenic modification is in the case of ‘cold resistant strawberries’. In one
variety genes from the arctic flounder, a fish that lives in very cold water,
were used to give plants resistance to cold. This modification works because of
the genetics of the arctic flounder. It lives in water where other fish would
freeze to death but, with a special gene that allows it to produce a sort of
anti-freeze, it can survive. This gene is put into a bacterium that is sprayed
on the strawberry during the freezing temperatures, allowing it to also be
resistant to cold. The strawberry is then cleaned, removing the bacteria.

Factors
effecting quality of strawberry:

 Effect of ozone treatment:

                   
Strawberry fruits (Fragaria × ananassa) were stored at 2 °C in an
atmosphere containing ozone (0.35 ppm). After 3 days at 2 °C, fruits were moved
to 20 °C to mimic retail conditions (shelf life). The changes in several
quality parameters such as fungal decay, colour, sugar and acids distribution, and
aroma were evaluated during the strawberries’ shelf life. Ozone treatment was
ineffective in preventing fungal decay in strawberries after 4 days at 20 °C.
Significant differences in sugars and ascorbic acid content were found in
ozone-treated strawberries. At the end of cold storage, the vitamin C content
of ozonated strawberries was 3 times that of control fruits. A detrimental
effect of ozone treatment on strawberry aroma was observed, with a 40% reduced
emission of volatile esters in ozonated fruits.

Thawing:

         Vacuum
infusion (VI), freezing, frozen storage and thawing conditions were optimized
to minimize the texture loss of frozen strawberries. Slow freezing caused
severe loss in textural quality of the strawberries. This quality loss could
not be prevented by the application of VI prior to slow freezing, or by the
application of rapid, cryogenic or high-pressure shift freezing conditions on
non-infused fruits. A remarkable texture improvement was noticed when infusion
of pectin methyl esterase (PME) and calcium was combined with rapid or
cryogenic freezing. The highly beneficial effect of PME/Ca-infusion followed by
HPSF on the hardness retention of frozen strawberries was ascribed to the
combined effect of the infused PME (53% reduction in degree of esterification
(DE) of the strawberry pectin) and the high degree of supercooling during HPSF.
During frozen storage, textural quality of PME/Ca-infused high-pressure frozen
strawberries was maintained at temperatures below ?8 °C, whereas the texture of
PME/Ca-infused strawberries frozen under cryogenic freezing conditions was only
preserved at temperatures below ?18 °C. Thawing at room temperature seemed to
be an appropriate method to thaw strawberries. Fast thawing by high-pressure
induced thawing (HPIT) did not prevent textural quality loss of frozen
strawberries. Frozen strawberries were thawed under different controlled
conditions (natural thawing at room temperature, thawing in circulating air,
thawing in a refrigerator, thawing in water and thawing in a convection oven).
The effects of thawing method on the weight loss in strawberries were
determined. Strawberries thawed at higher temperatures showed greater weight
loss. During thawing in circulating air, thawing time decreased with increasing
air velocity.

Conclusion:

           Postharvest decay of fruits and
vegetables triggered by inappropriate storage conditions, pathogenic attacks,
mechanical injuries and environmental stresses. To reduce postharvest losses
and extend shelf life of fresh produce, different techniques such as low
temperature storage, control atmosphere packaging and surface treatment with
synthetic chemicals have been widely practiced. Gamma irradiation has been
successfully used as an alternative treatment for microbial disinfection and
longevity of shelf life of fresh produce.