Sweet potato types, planting material,processing for food products, commercial products, industrial products,, animal feed, its storage and utilization of processing wastes and byproducts have been briefly explained

1. SHAKARKANDI - SWEET POTATO (Ipomea babatus L) PRODUCTION
TO VALUE ADDITION
Dr Jai Singh (ARS)
M Tech Ph D
Retd Director ICAR – CIPHET
Mob:8958463808 E Mail:jsingh.sre@gmail.com
INTRODUCTION
Shakarkandi (Sweet Potato) is a sweet starchy crop grown all over India. It is eaten
after boiling / steaming / roasting / frying or processing in to various edible products.
Industrial products like starch, glucose, sugar syrup, industrial alcohol, etc are also
produced. Ipomea Batatus (L) is the scientific name belonging to Convolvulaceae
family. It is assuming great significance as health food due to various bioactive
principles. It is three- in - one combining properties of cereals, vegetables and fruits.
Verities having yellow flesh are rich in carotene, a precursor of Vitamin A. It has wide
color range of skin (purple, brown, white purple) and flesh (yellow, orange, white
,purple). This presentation encompasses production, post harvest management and
processing value addition as food, feed, industrial and commercial products.
Local Names: Shakarkand (Hindi), Chilakada Dumpa, Moram Gadda (Telugu),
Sarkaraivalli Kizanku (Tamil), Genasu (Kannada), Ratala (Marathi), Kandamula (Oriya),
Mathura Kizhangu (Malayalam), Shakkaria (Gujarati), Shakkar (Punjabi), Rang Aloo
(Bengali).
Health Benefits: It is powerhouse of antioxidants and nutrients, rich source of fiber,
beta-carotene, iron, phosphorus and anti-inflammatory properties. Contains vitamins
‘B6’, ‘E’ and ‘C’. It is good for heart, helps in controlling blood pressure, relieving stress,
improving digestion, preventing cancer and diabetes, etc.
Varieties: Pusa Safed, Pusa Red, Pusa Sunahari, ICAR – CTCRI (H-97, H- 165, H –
226, Sree Sahya, Sree Visakham, Sree Prakash, Sree Jaya, Sree Vijaya, Sree Harsha,
Sree Apoorva, Sree Athulya, Sree Swarna, Sree Pavithra, Sree Rekha, Sree Prabha,
Sree Padmanabha), ICAR - CCARI ( NO- 4004, S- 30, Klamath , Skarkand – 5), TNAU
(Samrat – S-30, S30 – 21, SP local, SP 4, SP 13, SP 18 and Musiri), Punjab -21, H-
268, , NO- 4004, S- 30, Klamath , Skarkand – 5, Varsha, Konkan Ashwini, , Sri
Varadhi, Sri Bhadra , CO-3, CO CIP-1 and many more.
Yield : 6 to 10 tonnes / ha for rainfed crop & 12 to15 tonnes/ha under irrigated
condition besides 10 – 25 tonnes of vines
Growth Period : 90 – 120 days

2. Soil: Wel drained sandy to loamy loose friable soil, 30 cm depth, pH 5.8 to 6.7, for
better root development.
Planting Season: Jan – Feb and April – July in North, and June – July - September –
October in South.
Planting Methods : Ridges, furrows, mounds, pits, broad bed and flat beds are
common planting methods. Fully grown plants vine cuttings of 24 – 30 cm long or tuber
grown slips are planted on ridges in monsoon or in furrows / pits / broad beds / flat
beds in low rainfall areas at 60 cm from row to 30 cm within the row at 7 – 10 cm
depth. Nursery beds are raised from January to February for seedlings planting. .
Seed Rate: About 40- 50 thousand cuttings or 85 – 100 kg tuber slips are required
for an hectare land.
Manures and Fertilizer: FYM 10 – 15 tonnes at the time of soil preparing. 50- 60
kg N, 50- 60 kg P and 100 – 120 kg k /ha recommended. Half N, full P and K
applied at the time of planting, remaining ½ N after 30 days of planting.
Harvesting: Crop takes 3 – 5 months to mature. It is harvested when leaves turn
yellow and start shedding. Maturity is also judged by cutting tubers, if latex dries
up without turning black, the crop has matured. Before harvest vines are cut to
ground level and then the tubers are dug out and cured. The tubers should not
be cut or bruised.
Sweet Potato Curing: Freshly harvested roots are very susceptible to water loss due
to high moisture (60 – 70 %) and thin delicate skin resulting in 1-2 weeks self life.
Losses can be 20 – 70 %. Properly cured sweet potatoes can be kept for many
months. Curing process seal natural moisture in tubers and activate enzymes to heal
/ repair nicks and cuts / damages occurred during the harvest. Curing also hardens
the skin and improves the sweetness of the tuber. Curing is done by holding tubers 3
- 14 days at 27-32°C and 85-90 percent RH. Curing is done by exposing the whole
potatoes to a moderately high temperature for several days immediately following
harvest.;[1][3][8][13] 30–32 °C (86–90 °F) and 80–95% RH for 4–10 days has been found
to be adequate curing conditions .
Curing Methods:
Pre – harvest – field curing: (i) Leaving the crop as such for 1- 3 weeks after cutting
and removing vines / fpliage, (ii) Stacking tubers on elevated ground and covering by
black polythene 15 – 20 cm above layer during day time and removing in night and (iii)
Field piling and covering piles with vines for 7 days.
Pile Curing: Fresh produce is piled at higher ground level. The bottom, sides and
top covered with thick layer of grasses / woven mats.

3. Mound or Heap Curing: involves stacking or mounding the crops, covering them with a
thick layer of sand, cut grass, or straw for insulation, and then placing sacks, jute bags
or canvas tarpaulins over the mounds.
Wrapping Pubers in Black Polythene: A simple method to cure sweet potatoes is to
wrap tubers in black polythene sheets and leave out in the sun for 5 days. The black
sheet keeps moisture in and collects heat to reach necessary conditions for curing
Curing Barn in Warm Humid Areas: Uniform high temperature and humidity is
maintained by ventilation and insulation. Barn foundation is made moisture free and
floor, walls and coverage insulated.
Evaporative Cooled Structures - Zero Energy Cool Chamber (ZECC) : Can be used
to create warm and humid conditions (26-34°C, with 59-92% RH). ZECC could be
modified with a black plastic cover to increase the temperature and still maintain high
humidity.
Controlled Environment Curing: Small boxes, pallets or bags of tubers are placed in
the insulated room. Fan and heating devices are fitted in plenum chamber to force
heated air through the product stacks.
Removing vines/
foliage
Controlled
environment
curing
Evaporative cooled
curing chamber
Pile curing:Bottom
sides grass
insulated top black
poly
Vine covered
curing
STORAGE
Sweet Potato Storage: Preserving the fresh produce shelf-life remains a major
challenge to farmers. Cured unwashed sweet potatoes at normal room temperature
are stored in perforated containers / bags kept in dark, cool, dry, well ventilated rooms
away from heat sources. Tubers should be loaded in layers of 60 cm at 1 – 2 days
interval giving time for drying. Other methods include: in-ground storage, heap
storage, pit method, clamp and mound storage , sand pit storage, controlled
environment storage, passive evaporative cooling chamber storage, paper bags
storage, etc. Improved methods, such as refrigeration, deep freezing, waxing,
controlled atmosphere and chemical treatments can also be used.
(i) Temporary One – to Two Week Storage in Paper Bags: Sweet potatoes
are wrapped individually in paper bags and put in wooden boxes.

4. (ii) In – Ground Storage: The vines / foliage is cut and removed leaving the
tubers in ground which are dug out according to marketability. This is
called piece-meal or sequential harvesting
(iii) Heap Storage: Similar to clamp and mound method.
(iv) Pit Storage: Pit / trench is dug at higher and moisture free site keeping size
according to storage volume, Dry disinfected grass / sawdust / wood / ash
with lime is used to line the bottom and sides of the pit. It acts as insulation for
temperature change and moisture condensation. . Pit / trench top is sealed
with dry soil. Roof over pit is erected to protect against rains. Suitability 2 – 4
months.
(v) Clamp and Mound Storage: Harvested tubers are piled on ground at
higher level. Tubers are stacked in heap on a layer of grass and
covered in layers of grass and soil. Dry disinfected grass / sawdust /
wood / ash with lime is better. Top is covered by dry soil. Suitability 2 – 4
months.
(vi) Indoor Storage: Store produce in straw woven baskets, cloth bags or
wooden boxes.
(vii) Storing in Sand Sweet Potato can also be stored in sand packed in layers in
pits, trenches, barrels or crates. The sand cushions them and prevents injury
and keeps the sweet potatoes cool.
Clamp syorage
Pit storage
Environment controlled
storage
Room Storage Evaporative cool
storage
CLEANING, SORTING, GRADING, PACKING:
Soil laden Sweet
Potatoes
Cleaning washing Sun drying Sorting grading Packing consumer
pack

5. Net Packing Box packing Sack packing
Mandi market
Sweet Potato Handling and Marketing : The secrets of securing high prices are:(1) to properly
grade, clean, and pack , (2) to place in market at a time when there is greatest demand and (3)
to have storage facility for 1 – 5 months. Proper handling from the farmer’s field to the
consumer’s kitchen is important to reduce 20 – 25 % losses during curing and storage, 5 – 10
during rmarketing and 10 – 15 % retailer to kitchen. It needs proper curing; gentle handling;
minimize cuts and abrasions; washing, cleaning, waking ;proper storage to minimize shrinkage,
sprouting; grading, packing, transport and quality certification.
ANIMAL FEED FROM FOLIAGE
Vines and Leaves for Animal Feed: The vines / foliage are valuable feed for livestock.
These can be fed to cattle, sheep, goats, pigs and rabbits. It may be fed fresh, dried or
ensiled, and makes a very palatable silage with a pleasant fruity smell. Sweet potato
forage can also be dried, ground and mixed with sugarcane by-products. Other sweet
potato processing wastes and biproducts are suitable for livestock. Vines are chopped
to 0.2-0.5 cm length, prewilted in sun for 1-4 h to 40-45% moisture. It is mixed with 10%
rice / wheat straw and 0.5% salt and heavily pressed in silo pits or plastic bags .
Sweet potato foilage Foliage wilting Ensiling in pit Ensiling in bags Drying for hay /
powdering
SWEET POTATO PROCESSING BYPRODUCTSAND WASTES :
Vines and leaves - animal feed, source of protein, vitamins, minerals, pigments, lactic
acid and polyphenol.
Peels, trimmings, chunks of tuber - Soluble fiber, phenolic compounds, lactic acid,
biogas, pigments,
Waste water – bio fertilizer and biogas.

6. Peels Leaves Vines Culled tubers
Processing slurry
SWEET POTATO TUBERS SKIN AND FLESH COLOURS
SKIN: yellow, purple , brown, white
FLESH white , yellow, orange purple
White and purple
Yellow,Purple, White,
Orange
SWEET POTATO PLANTING MATERIAL
Sweet potatovines
cuttings for
planting
Nursery grown
planting material
Sweet Potato Slips Sweet Potato
Slips
Slips from tubers Tuber cuttings
to grow slips
SWEET POTATO PLANTING METHODS
Well tilth field Ridges / furrows Broad base seed
bed
Flat seed bed
Pit seed bed Mounds for
planting
Slips for planting Burring cut vines in
furrows

7. Furrow planting Ridge plantinf Mounds planting
Nursery raised
seedling planting
Full grown crop
Yellowish crop
ready to harvest
Removing vines
before digging
Digging tubers
Curing to harden and
heel injury
Cured produce for
market
PROCESSING AND VALUE ADDITION
SWEETS MADE FROM SWEET POTATO: Only few are mentioned
Chocolates Desserts Gulab Jamun Casserole Puran poli
Pie Noodles Cakes
Chinnamon rolls Candied Sweet

8. Jalebi Sweet Sweet Laddoo Barfi
SWEET POTATO SNACKS : Only few are mentioned
Bhel Chips Wada
Cutlet Samosa
Bonda Tikki Patti with sesame Wedges
NOODLES
CHIWDA
Fries
Snack bar
SWEET POTATO FOOD PRODUCTS: Only few are mentioned
Different types
Curry
Different types
Bhaji
Fritters Rosted
Different types
Sabji
Ban Pizza Shak Tawa Fry Raita Kheer

9. Halwa Stuffed Paratha Podi Papad Wadi
SWEET POTATO COMMERCIAL PRODUCTS: Onlyfew are mentioned
Fermented Juice Juice Jam Flour – as flesh
color
Vinegar- as flesh
color
Jelly
Butter spread Bread Nectar Canned
Soup
Sauce
Baby Foods Puree Super foods
Baked fries
Frozen
Murabba
Sweet Potato Industrial Uses:
Starch: Sweeteners, citric acid, beverage, noodles, industrial alcohol, ethanol, fuel
and maltose.
Other Products : Liquor, pigments, cosmetics, syrups.
Literature Consulted: ICAR – IARI,ICAR – CTCRI, ICAR – CCARI, PAU, TNAU and
others.
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