New Technology
RECENT
ADVANCES IN POST HARVEST TECHNOLOGY OF
VEGETABLES
AND FRUITS IN PAKISTAN
1.
ABSTRACT
In Pakistan the magnitude of post
harvest losses of vegetables and fruits is about 35%. Efforts
are being made both at federal and provincial level to
minimize these losses to safe guard the interest of growers,
processors, traders, retailers and consumers. However, the
primary objective of research and development activities on
post harvest handling and quality preservation of vegetables
and fruits being carried out in the country is our national
food security and to promote export of these high value
commodities to other countries. The recent advances made in
the area of post harvest technology and research in Pakistan
are discussed in this paper.
2.
INTRODUCTION
Agro-climatic conditions of Pakistan ranging from
tropical to temperate allow growing 40 different kinds of
vegetables and 21 types of fruits (Raja, M.B. and K.M. Khokhar,
1993). Major vegetables grown in Pakistan include potato,
onion, chilli, melons, cucurbits, tomato, turnip, okra and
pea, whereas citrus, dates, mango, guava, apple, banana,
apricot, grapes, almonds, peach, plum and pomegranate are the
main fruit crops. At present area under fruits and vegetables
is 0.995 million ha (4.3% of the total cropped area) with the
total production of 10.992 million tonnes (Government of
Pakistan, 1999). Area and production both increased in the
past but at a very low pace. The major factor limiting
increase in area and production remained high investment and
low return to the growers. Postharvest losses in fruits and
vegetables range from 25-40% (Raja, M.B. and K.M. Khokhar,
1993) or even qreater (Iqbal, M., 1996). Consumers prices rise
in addition to hidden quality losses. These losses bring low
return to growers, processors and traders and country also
suffers in terms of foreign exchange earning. In fruits and
vegetables the quality of produce starts deteriorating right
after their harvest. Primary factors responsible for
post‑harvest produce losses are: poor pre‑harvest
measures-- adoption of poor production techniques (varieties
with low shelf life, imbalance use of nutrients, insect pest
and disease infestation and abiotic stresses; low tech
harvesting procedures-- non‑application of
pre‑harvest recommended treatments/practices, harvesting
at improper stage and improper care at harvest; and
post‑harvest problems-‑ non‑removal of field
heat, dumping produce, moisture condensation causing pathogen
infestation, packaging in bulck with out sorting and grading
of produce, improper transportation and storage, and distant
and time consuming market distribution (Kader, A.A., 1992). In
order to preserve the produce quality different post-harvest
techniques are recommended for variety of produce. These
techniques include; hydrocooling, refrigeration &
freezing, modified atmosphere (MA) packaging, MA storage,
control atmosphere storage, skin coating, hypobaric or
low pressure storage, irradiation, dehydration, canning, high
pressure processing and pulsed electric fields and pulsed
light applications. In order to promote horticultural industry
in Pakistan, standardization of pre-harvest and post-harvest
management technologies minimizing postharvest losses and to
enhance foreign exchange earning to the maximum extent are
therefore essentially required for necessary adoption. At
present various R&D institutions are working on different
aspects of postharvest management of vegetables and fruits.
3.
RESEARCH INFRASTRUCTURE
Information on institutions and their involvement in
postharvest handling, dehydration, processing and
preservation of fruits and vegetable work is given in
Table-1.
Table-1: Institutions
involve in postharvest research work on vegetables and fruits.
Institution |
Postharvest
Research Work |
I.
Federal Institutions
|
|
National
Agricultural Research Centre, Islamabad |
Variety
screening (tomato, peach), packaging, (citrus),
storage (loquat, citrus, mango) |
Nuclear
Institute for Agriculture and Biology, Faisalabad
|
Citrus
coating, packaging, grading & storage
|
Nuclear
Institute for Food and Agriculture, Peshawar
|
Irradiation
(vegetables & fruits), sprout inhibition,
dehydration
|
Pakistan
Council for Scientific and Industrial Research, Lahore
|
Vegetable
dehydration
|
II.
Provincial Institutions
|
|
|
|
University
of Agriculture, Faisalabad
|
Fruit
& vegetable preservation, processing
|
Ayub
Agriculture Research Institute, Faisalabad
|
Handling
& storage (citrus, mango, onion, potato), fruit
& vegetable preservation
|
Agriculture
Research Institute, Tarnab, Peshawar
|
Fruit
processing (apple, plum pomegranate, lemon, guava)
|
Agriculture
Research Station(N) Mingora, Swat
|
Persimmon
dehydration, processing
|
Agriculture
Research Institute Sariab, Quetta
|
Fruit
handling (apple, grapes, apricot, dates)
|
Sindh
Horticulture Agriculture
Research
Institute, Mirpurkhas
|
Fruit
processing (mango, dates, lemon, guava, papaya),
vegetable dehydration (tomato)
|
For proper redressal of the key
issues a well coordinated research and development programme
at national level is however lacking.
4.
ADVANCES IN
POSTHARVEST TECHNOLOGY AND RESEARCH
Information on recent advances
made in postharvest technology and research at various
institutions in Pakistan (also include as given under
references) is summarized below.
4.1 Selection of varieties for
better shelf life
Vegetable varieties: Riogrande, Roma AVRDC Cv.
(tomato), NARC ‑ 91 (onion), Medium Long Green (chillies),
Local Selections (cucumber) and VIP (pea) have shown better
transportation quality and longer shelf life. In fruits;
varieties: Begum Jangi (date palm), Cardinal, Flame Seedless
(grapes), Local Selections (fig), Sultan (pomegranate) and ARS
(N) Mingora No. 7, No. 8 & No. 9 (peach) were found high
yielding with longer post‑harvest life.
4.2 Influence of rootstocks on
postharvest quality of some apples
Studies carried out at Deciduous Fruit Development
Centre, Sariab, Quetta revealed that on rootstock MM 106,
apple cultivars (Red Delicious, Golden Delicious, Star King
Delicious and Spartan) showed better performance than on
M‑9 rootstock for fruit texture and soluble solids. On
the basis of organoleptic evaluation or consumers'
acceptability' MM‑106 showed partially better
performance than M‑9. For skin colour of fruit,
rootstock M‑9 showed better results over MM‑106.
However, rootstock MM-106 should better performance in terms
of fruits texture, total soluble solid contents and consumers'
acceptability over M-9 rootstock.
4.3 Pre-harvest application of
fungicides
Pre-harvest application of Benlate 50 WP minimized mold
growth and increased shelf life of citrus (Kinnow Mandrin) at
ambient storage temperature.
4.4
Pre-harvest application of growth hormone
GA3
when applied @ 20 ppm on grape Cv. "Kishmish" not
only increased the berry size, yield, protein, reducing &
non‑reducing sugars, pectin and ascorbic acid but also,
the mineral contents of berries (sodium, calcium magnesium and
iron contents) were increased hence improved the quality of
fruits and also its postharvest longevity.
4.5
Postharvest application of calcium chloride
Freshly harvested tomato fruits of variety" Nagina"
when dipped in 4% CaCl2 solution and kept at 15oC maintained
marketable quality upto 16 days.
4.6
Studies on degreening of citrus and mango
Studies
on degreening of citrus and mango showed that citrus variety
"Salustiana" stored at 30oC and 85‑90% RH
(controlled atmosphere) developed uniform colour after
24 hours, whereas in case of variety "Honey Mandrine"
there was a slight colour development even after 36 hours. In
case of mango variety "Chaunsa" stored at 17oC and
80‑85% RH after chilling resulted uniform colour
development and produced natural flesh taste.
4.7 Studies on wax coating
materials
Wax
coating studies are being carried out to make the produce more
attractive with better shelf life. Carnauba based surface wax
increased shelf life of Kinnow 3‑4 weeks by delaying
senescence. Edible film coatings with gelatin (4%), corn
starch (3%), HPMC (3%) and stearic acid (1.5 to 3%)
composition enhanced storage life of carrots variety,
"T‑29" upto 45 days with minimum
(10‑15%) post‑harvest water loss.
4.8
Studies on potato storage
Autumn
potato crop is the main crop grown in the plains of Punjab.
The crop is harvested during the month of January. The produce
is kept in the field until the end of February because of low
temperature. Thereafter, potatoes are mostly stored in the
field in ordinary storage structures, where weight loss,
rotting and sprouting of tubers deteriorate the quality of
produce. In cold storage the produce is held at 4-5oC. At this
temperature starch is converted to sugar and therefore
potatoes become sweet. Also, because of high charges of
electricity this costs much higher as compared to ordinary
storage conditions or storage of potatoes at relatively higher
temperature. Studies associated with these problems reveal
that:
1.
Improved low cost on-farm storage structure (where hot air is
replaced by cool air during night using electric fan) the
inside temperature was observed 3-4oC low and the stored
potatoes retained marketable quality upto 90 days.
2.
The sprout suppressant,
"Camptothecin" when applied (sprayed) @ 0.5 mM
inhibited sprouting of tubers upto 45 days at 39oC,
whereas in untreated control sprouting started after 30 days
at 39oC.
3.
The
sprout suppressants CIPC @ 1500 ppm and 2000 ppm, IPC @ 1500
IPM and 2000 ppm and DECCO - 276E (combination of CIPC
and IPC) @ 4.4 ml/100 ml water spray checked weight loss, sprouting
and sweetening when potatoes were held at 5oC and 9oC storage
temperatures and 90% RH until 105 days.
4.
Quality of potato tubers when held at 5oC or 9oC and 90% RH
was retained until 60 days as the weight loss, rotting,
sprouting and sweetening were checked.
4.9 Studies on date palm storage
Results
on date palm post‑harvest storage indicated that
‑3oC was the optimum storage temperature for variety
"Dakki". After one month of storage T.S.S. increased
from 38.5% to 42.0% with 38.6% weight loss
4.10 Studies on tomato fruit
storage
In case of tomato, variety "Nagina" when
dipped in 4% CaCl2 solution and kept at 15oC maintained
marketable quality upto 16 days.
4.11 Studies on olive
preservation
Olive
fruit when preserved using 15% NaCl solution was found
successful.
4.12
Quality preservation of apricots
Apricots when
dipped @ 3% solution of potassium meta bisulphite for 3 hours
and then dried proved to be
successful.
4.13
Radiation effects on extending shelf life of some fruits and
vegetables
Nuclear
Institute for Food and Agriculture (NIFA), Peshawar
demonstrated inhibitory effects on sprouting of onions and
potatoes during storage; delay in ripening in banana, guava,
mangoes, pears, tomatoes and persimmon; rot control in oranges
and improvement in quality of mature green peaches by using
safe levels of Gama radiations.
5. SUMMARY
Selection
of varieties according to the market requirement coupled with
improved production practices would ensure minimum wastage
after harvest. For country like Pakistan low cost,
economically feasible technology such as on-farm low cost
storage (structures) hydrocooling, MAP, CA storage and
waxing/skin coatings seems to be appropriate. Sorting and
grading are pre-requisite for appropriate packaging and market
distribution. Low cost energy efficient on‑farm storage
structures are to be introduced on extensive scale. Packaging
has to be cost effective. Dehydration of vegetables and fruits
is to be introduced as cottage industry. Preservation and
processing of vegetables and fruits both at semi- commercial
and commercial scale needs to be carried out. The
aforementioned items would ensure optimum return to growers
and traders. Better produce handling and management would
ensure regular market supply and the consumers will enjoy the
affordable prices. This will also help promoting export of
high value perishable commodities to other countries. A well
coordinated R&D programme on produce handling and
marketing at national level is, therefore, essentially
required.
6.
REFERENCES
-
Ayub
Agricultural Research Institute. 1998. Annual Research
Programme Meeting of Horticulture Research Institute,
Vegetable Research Institute, Postharvest Technology
Centre and Food Technology Section, 08 October 1998,
Faisalabad.
-
Government
of Pakistan. 1999. Agricultural Statistics of Pakistan
Ministry of Food, Agriculture & Livestock. Economic
Wing, Islamabad.
-
Iqbal,
M. 1996. Type and extent of postharvest losses in
horticultural commodities on Pakistan (pp:33-42). In:
Proceedings of national conference on postharvest
technology of horticulture commodities, 10-12 September,
1996, Quetta.
-
Kader,
A.A. 1992. Postharvest Tec hnology of Horticultural Crops.
Second Edn. University of California, Division of
Agriculture and National Resources. Publication 3311.
- Nuclear
Institute for Food and Agriculture. 1996. Annual Report,
NIFA, Peshawar.
- Raja,
M.B and K.M Khokhar. 1993. Postharvest horticulture
technology and its future prospects (pp:265-277). In:
proceeding of first international horticulture seminar,
09-11 January 1992. Pakistan Agricultural Research
Council, Islamabad.
|