Maturity indices of fruits and vegetables

Topic : Maturity indices of fruits and
vegetables
SUBMITTED BY
S. SHARVESH
M.Sc (Hort.)Fruit science
Annamalai university
ANNAMALAI UNIVERSITY
FACULTY OF AGRICULTURE
DEPATMENT OF HORTICULTURE

Maturity indices of fruits and
vegetables

IMPORTANCE
 Diverse agro-climatic regions enables cultivation
of a number of fruits, and vegetables.
 India looses about 25 to 30% of the produce
during post-harvest handling and mismatching
harvest, with proper maturity of fruits plays a
great role.
 In general, picking of immature fruits results in
poor quality, lacking in flavour and taste, which
shrivel during storage.
 Over mature fruits develop soft scald and
internal breakdown with poor shelf life.
 Thus, harvesting of fruits at right maturity is
essential to improve fruit quality and minimize
post-harvest losses.

MATURITY
 It is the stage of fully development of tissue of fruit and
vegetables only after which it will ripen normally
 During the process of maturation the fruit receives a regular
supply of food material from the plant
 When mature, the abscission or corky layer which forms at the
stem end stops this inflow
 Afterwards, the fruit depend on its own reserves

Horticultural maturity vs ripening
 Maturity may be defined as the attainment of a
proper size after which ripening takes place.
 Ripening means the qualitative changes in fruits
after maturity as a result of which it becomes
edible.

 In addition to this, typical flavour and characteristic colour also
develop
 It has been determined that the stage of maturity at the time of
picking influence the storage life and quality of fruit
 when picked immature like mango develop white patches or air
pockets during ripening and lacking in normal brix acid ratio or
sugar acid ratio, taste and flavor
 on the other hand if the fruits are harvested over mature or full
ripe they are easy susceptible to microbial and physiological
spoilage and their storage life is considerably reduce

 Such fruits persist numerous problems during handling, storage
and transportation
 Therefore, it is necessary or essential to pick up the fruits or
vegetables at correct stage of maturity to facilitate proper
ripening, distant transportation and maximum storage life
 The postharvest quality of the product is fixed at the harvest so
proper harvesting is necessary
 We can have good harvest if we harvest at proper time as the
development of the fruits is at later stage of development

 Fruits harvested too early may lack flavor and may not ripen
properly, deteriorate faster and have short shelf life
 while produce harvested too late may be fibrous or have very
limited market life
 Yield may also be lower
 Therefore harvesting of fruits and vegetables at proper stage of
maturity is of paramount importance for attaining desirable
quality
 The maturity has been divided into two categories i.e.
physiological maturity and horticultural maturity.

 Horticultural maturity/Commercial maturity
 Stage of development when plant parts possess the necessary
characteristics preferred by consumers
 Depends on the intended use e.g. papaya, jackfruit
 Physiological maturity
 Applies only to fruits and fruit vegetables
 End of development stage
 Ability to ripen normally after harvest
for distant market and storage,
o climateric fruits should be harvested at maturity before they are
ripe i.e. before climateric rise
o Non climateric fruits should be harvested at ripe stage

Importance of maturity indices
 Maturity indices = harvest indices
 Sensory and nutritional quality
 Adequate shelf life
 Facilitate marketing- standards
 Productivity

Too often we are on the side of shelf life at the
expanse of good eating quality

Maturity indices
 Sign or indications of the readiness for harvest
 Basis for determining harvest date
 Two types of maturity indices
i) Subjective:
 Qualitative
 Use the senses (color, size, shape, sound, firmness, juice
content etc.)
ii) Objective:
 Quantitative
 Are measurable indices (TSS, TA, Starch content, oil content,
firmness, dry matter, Days after full bloom, heat degree day,
respiration and ethylene production, production of volatiles etc.)

Types of indices
i) Visual indices
a) Size and shape:
 Maturity of fruits can be assessed by their final shape and size at the time of
harvest.
 Fruit shape may be used in some instances to decide maturity.
 For example, the fullness of cheeks adjacent to pedicel may be used as a guide to
maturity of mango
 Banana : angular shape changes to round

b) Colour:
 The loss of green color of many fruits is a valuable guide to
maturity

ii) Physical indices
a) Firmness:
 As fruit mature and ripen they soften by
dissolution of the middle lamella of the
cell walls.
 In many fruits such as apple, pear,
peach, plum, guava, kinnow etc. firmness
can be used to determine harvest
maturity.
 Penetrometer measures the pressure
necessary to force a plunger of specified
size into the pulp of the fruit.
 Such pressure is measured in pounds
and kilograms force.

b) Specific gravity:
Specific gravity is the ratio of the density of a substance to the
density of a reference substance.
As fruit mature, their specific gravity increases.
This parameter is rarely used in practice to determine when to
harvest a crop
It is used to grade crops into different maturities.
To do this the fruit or vegetable is placed in a tank of water;
those that float will be less mature that those that sink.
In practice, the fruit or vegetable is weighed in air, then in pure
water. The weight in air divided by the weight in water gives
the specific gravity.

iii) Chemical Measurement
 The total soluble solids of the fruit can be measured with refractometer, which
indicate the harvest maturity of fruits.
 Acidity is readily determined on a sample of extracted juice by titration with
0.1 N NaOH.
 TSS/TA is better to judge maturity as it gives the sugar acid blending of
product
a) Total Soluble Solids
 can be determined in a small sample of fruit juice using hand refractometer
 The refractometer measures the refractive index, which indicates how much
a light beam will be slowed down when it passes through the fruit juice.
 The refractometer has different scales (0-32OB), (28-62OB) and (56-92OB)
which can be read directly.

 For large size fruits, these should be cut from stem to blossom
end and to the centre of the fruit to account for variability in TSS
from top to bottom and inside to outside of the fruit.
 The fruit tissues should be macerated thoroughly in pastle motor
and then from the mescerated pulp the juice is extracted by
passing through muslin cloth.
 A drop of juice is then put on the prism of the refractometer and
TSS content can be read directly on the scale.
 However, in case of small fruits like grapes, the juice content
can be extracted by simply pressing the whole fruit.

b) Titratable acidity:
Titratable acidity (TA) can be determined by titrating a know
volume of juice with 0.1N NaOH to end point
The milliliters of NaOH needed are used to calculate the TA.
The TA expressed as percent malic, citric or tartaric acid can
be calculated as follows:

iv) Calculated indices:
a) Calendar Date/Days after full bloom :
Useful guide to harvest, where seasonal variation in climate is
small
This method works well when the blooming period is short
period
b) Heat Units:
It has been found that a characteristics number of heat unit or
degree-days is required to mature a crop under usually warm
conditions
It is based on the principle that growth of plant organ is
directly proportional with ambient temperature

V) Physiological Method:
Respiration rate:
 Particularly on climateric fruits can accurately pin point the
most appropriate time of harvest as there is climateric rise
in respiration
Internal ethylene evolution:
 Like respiration rise climateric fruits also have ethylene
peak
Volatiles production:
Apple: Ethyl-2-methyl butyrate
Banana: Eugenol
Grapefruit: Nootaketone
Lemon: Citral
Orange: Valencene

 Maturity indices should be
 simple, easy to carry out
 Objective vs subjective indicators
 Related to quality
 Related to storage life
 Represents a progressive change with maturity
 Premits prediction of maturity from year to year
 inexpensive

 Limitations of maturity indices uses
 Soil conditions, nutrition, irrigation
 Season , climate
 Position on the plant
 Pruning and other cultural practices and
management practices
 varieties

 Maturity (Commercial or Horticultural maturity) : refers to the stage
at which the produce is optimally accepted to the consumer.
 Maturity index: The maturity at harvest determines the quality and
post- harvest shelf-life of the fresh fruits. The study of maturity
indices helps to harvest the crop at right time.
 Judging maturity: There are various means of judging maturity but
they vary according to the kind of fruits, local soil and climatic
conditions, but generally farmers follow visual means
(appearance). But this is not a perfect method, many a times it may
mislead the farmers.
 There are certain limitations for all maturity indices due to variation
in nutrition of the crop, fruit shape, size, climate, seasonal factors,
moisture, pruning method, use of hormones and other chemicals.
We can use various indices to judge maturity.

 Slight colour development on the shoulders.
 When one or two ripe fruits fall from the tree
naturally (tapka method).
 Skin colour changes from dark green to olive
green.
 Counting of the days from fruit set to maturity.
 When the specific gravity of fruits ranges
between 1.01 to 1.02.
 Flesh firmness

 Lenticels become more prominent and waxy bloom
gradually disappears.
 When the TSS reaches 1 1-15o Brix.
 The first and second methods are not of much help
since these are not representative of the fruit maturity
of the entire tree and the fruits harvested do not ripe
uniformly.

MANGO
 Change in peel colour on the shoulders.

 ii. Falling down of some ripe fruits from the tree
(tapka).

 iii. Specific gravity of most of the fruits reaching
between 1.01 and 1.02.

 iv. Number of days taken by the fruit to mature

1. The fruits are harvested at different maturity
level based on distance of transport.
2. For long distance transport 75-80% maturity
and for short distance transport 90-100%
maturity fruits can be harvested.
3.
1. When the pulp peel ratio reaches 1.2 - 1.6.
4.
2. Days taken from shooting, i.e., 3.0-3.5
months.
5.
3. Disappearance of angularity of the fingers.
6.
4. Brittleness of floral ends.
7.
5. Drying of leaves in some varieties.
BANANA

 Bananas are harvested while fully mature but
green and transported to the markets, where
these are ripened artificially under controlled
conditions.
 For local markets, the banana should be
harvested when the ridges on the surface change
from angular to round.
 Fall of floral remnants, pulp to peel ratio (10 :1),
pH of fruit (5.2-5.6) etc. are also good harvest
indices in banana.

GUAVA
 Guava fruits generally take about
17-20 weeks from fruit set to reach
maturity.
 When the colour changes from dark
green to light green.
 When the specific gravity is one (1.0).

 Guava is consumed at different stages of fruit
growth and development.
 The recommended optimum stage for
harvesting is about 2-3 weeks before attaining
full growth.
 Peel and pulp texture, peel colour, sugar and
tannin contents, TSS and titratable acidity, may
also be adopted as maturity indices

GRAPE
Grape is harvested when they reach
a TSS of 16 to 24% depending on variety.
Bangalore blue : 12-14%
Anab-e-Shahi and Selection – 7 : 16-18%
Thompson seedless : 20-22%

Besides TSS, the following physical characteristics are
also useful in judging maturity.
 Texture of pulp (softness)
 Peel colour (light yellow)
 Easy separation of the berries from the bunch
 Development of characteristic flavor and aroma.

 Grapes ripen only on the vine, so ripening
standards are practically applicable for
harvesting.
 Grapes are considered ripe when the fruits have
reached the condition of accumulation of sugar
and acid contents, which are the best suited for
intended use.
 At harvest, the berries should have attained
attractive appearance, good eating and keeping
quality and TSS/acid ratio.
 Heat units are other useful criteria for predicting
maturity in grapes.

PAPAYA
 For local market: When skin colour
changes at the apical end of the fruit.
 For long distance transport: When the
skin colour changes from green to yellow
to the extent of 6%.
 When the latex of the fruit becomes
almost watery.

 Maturity identification to ensure adequate fruit
ripening and good eating quality- major problem
 For local markets, half-yellow fruits should be
harvested.
 Fruits can also be harvested at the appearance
of yellow streaks on the dark green surface.
 Softness to touch, seed colour, jellyness of seed
and the change in latex colour (from white to
watery): Other indices

PINEAPPLE
For local market: When 25% of surface changes to yellow colour.
For long distance: When all the eyes are still green and have no
trace of yellow colour (75-80% maturity)
In India:
1. Pineapples are harvested when the colour changes from green to
greenish yellow.
2 The fruit develops a smooth surface around the eyes.

3. The flattening of eyes.
4. TSS : acid ratio of 21 to 27 and specific gravity of 0.98
to 1.02.

JACK FRUIT
 A dull, hollow sound is produced when the fruit is tapped
by the finger.
 The last leaf of peduncle turns to yellow.
 Fruit spines become well developed and widely spaced.
 An aromatic odour develops.

POMEGRANATE
I. The fruits are ready for harvest between 135-170
days after anthesis.
II. The fruit colour changes in summer to dark yellow
and in winter to dark red.
III. The persistent calyx at the anterior end of the fruit
curves inward and become hard and dry at maturity.
IV. Rind is very hard

 Days after pollination, peel colour and TSS: acid
ratio good maturity indices
 Fruits are harvested between 135 to 170 days
after anthesis.
 When their peel turns slightly yellow (summer)
or red (winter).
 Fruits give a metallic sound when tapped.
 The properly mature fruits are easily scratched
with a finger nail.
 The TSS:acid ratio ( 70:1)

SAPOTA
 The peel shows a dull orange or
potato colour with a yellowish
tinge when scraped.
 The scurf content on the surface
of the fruit will be minimum and
easily fall off.
 The content of milky latex drops
to almost zero.

 Fruits dull orange or potato in colour.
 Fruit show light yellow streak after scratching
instead of a green streak, which is a sign of
immature condition.
 Disappearance of brown scaly material from the
fruit surface.
 Dropping of the milky latex content almost to
zero.
 Falling of the dried spine like stigma at the tip of
the fruit automatically or by touch.

CITRUS
 Maturity indices differ among the citrus
species/varieties.
 Mandarins : When the rind colour
changes from green to orange colour.
 Sweet orange: When the rind colour
turns to yellow.

 Development of proper colour, TSS:acid ratio are
the best maturity indices.
 The preferred sugar:acid ratio for sweet oranges
is 8.5 to 8.9 and for mandarins between 10.5 to
13.0.
 For Kinnow mandarin, this ratio should be
between 12.1 to 14.1.
 In Kinnow, colour break occurs much before the
maturity, the TSS/acid ratio (12:1 to 14:1) should
therefore, be taken as index of maturity.

Limes: When the rind colour changes to light green
to yellow colour.
The International Standards Organization has set
in minimum juice content of citrus as follows.
 Washington Navel Oranges 30%
 Other orange varieties 35%
 Grape fruit 35%
 Mandarin orange 33%
 Lemons and limes 25%
 For processing total juice content of the fruit is
important.

FIG
 When fruits become soft and wilt at
neck.
 Fruits hanging down from their own
weight.
 No milk exudation from the stem
when the fruit is pulled off.

CUSTARD APPLE
 When the fruit turns to light green colour.
 Development of yellowish white colour between the
carpels.
 Initiation of widening the gap between carpels or
segments.

BER
 Attainment of full size of particular cultivar with softening of
pulp.
 Development of characteristic yellow or golden yellow colour.
 Days to mature the fruits.
Ex: In Delhi cv. Gola took only 150 days where as Tikadi
requires
173 days to mature.
 In cultivars like Gola, kaithli and umran , there was an increase
in reducing and non-reducing sugars, total sugars and TSS.

BER
 Change in fruit colour from green to pale,
titratable acidity, total soluble solids and specific
gravity of the fruit are the maturity indices for ber.

DATE PALM
Sl.
No.
Stage Characteristics
1
Doka
(khalal)
Fruit becomes hard, yellow or pink or red, TSS-
30 to 45%, astringency present or absent
depending o cultivar, Edible stage.
2
Dang
(rutab)
Softness starting at tip of fruit, tannins and
astringency disappears, lose weight and
moisture content is about 35 – 40%, Edible
stage.
3 Pind
(tamur)
Fully ripe fruit, lose weight, TSS- 60 to 84 %,
Edible stage.
It can be harvested at 3 different stages.

 The dates are eaten at different stages of
maturity, depending upon the variety.
 In general, dates are harvested at dang stage of
maturity, when the fruits start softening.
 In India, dang stage is never reached due to pre-
monsoon showers and hence these are
harvested at doka stage, when the colour of fruit
starts changing to pink and the astringency
decreases significantly.

LITCHI
 Flatness of tubercles and comparative
smoothness of epicarp
 change in pericarp colour is the most commonly
used as harvesting index.
 0Brix:acid ratio (70:1) is adopted internationally
as the commercial maturity standard for litchi

APPLE
 Apple is a climacteric fruit and thus maturity of
fruit does not coincide with the ripening.
 Picking of immature fruits results in poor quality,
lacking in flavour and taste, which shrivel during
storage.
 Over mature fruits develop soft scald and
internal breakdown with poor shelf life.
 TSS, ease in separation of fruit from the spur,
change in colour from green to pale or red, fruit
firmness and DFFB harvest: some reliable
maturity indices
 Iodine test

STRAWBERRY
 For local markets, fruits are usually harvested
when 2/3rd to 3/4th part of berries has attained red
colour.
 For distant markets, berries are sometimes
harvested when colour development has just
initiated and berries are hard.

PEACHES AND PLUMS
 Days from full bloom to maturity is the best
maturity index for peaches and plums.
 Fruit size, firmness, sense of touch, ground
colour, sugars, acidity, sugar:acid ratio etc., have
been assessed, can be used as maturity index
for harvesting peaches and plums.

ANOLA
 The colour of the fruit is the most reliable
harvesting index in aonla.
 The fruits are normally light green but on
maturity and ripening, the colour becomes dull,
greenish yellow or rarely brick red.
 Vitamin C content can also be taken as a reliable
maturity index.

MATURITY OF VEGETABLES
 Physiological maturity is the stage of
development when maximum growth and
maturation
 Commercial horticultural maturity is the stage of
development required by the market.
 Maturity at harvest affect its marketability and
storage life, nutritional content, freshness, flavor
Over mature vegetables will be stringy and
coarse.

Harvest criteria according to edible plant
part
 Fruit vegetables

 Immature fruit
 Tender, easily damaged
 (Legumes, cucumberber, squashes, eggplant, peppers, okra).
 Harvesting is primarily based on size and color. Maturity is not a
real problem unless the harvest is delayed too long and they
become over mature.

 Mature fruit
 (Muskmelon, watermelon, pumpkins, tomatoes, ripe peppers).
 Harvest index depends on several characteristics and is
dependent on the vegetable. Consumed at ripe stage, continue to
increase in eating quality if allowed to fully ripen on plant, but little
shelf or storage life

Leafy vegetables
Quality and shelf life are better if harvested slightly
immature. The determination of horticultural maturity
varies with the commodity, but generally size is the
principal criterion.
Floral vegetables
Hand harvested. Head size and development determine
maturity of floral vegetables. Floral vegetables include
artichoke, broccoli, and cauliflower.
Roots, tubers, and bulb vegetables
Maturity indices vary with commodity. Many of these
products can be harvested and marketed at various stages
of development.

Maturity indices
for specific
vegetables

CAULIFLOWER
 Sunlight is excluded (blanched) when the curds of
the cauliflower are 1 to 2 in. in diameter by loosely
tying together the outer leaves above the curd
(head) with a string or rubber band.
 The curds are harvested when they are 4 to 8 in. in
diameter and compact, white, and smooth.
 The head should be ready 10 to 15 days after tying.

CABBAGE
 Cabbage heads are harvested when the heads feel
hard and solid but before they split.
 The outer leaves should be uniform green or purple
color (depending on type

BRUSSELS SPROUTS
 When sprouts are 1 to 1½ inch in diameter and
firm.
 Lower leaves along the stem are often remove to
hasten maturity

BROCCOLI
 Head is dark green with a compact cluster (about 6
in. in diameter) of tight flower buds
 Before any yellow flowers appear.
 The head is cut 6 to 7 in. below flower heads.

TOMATOES
Tomato fruits are harvested at the required ripeness
stage for marketing or consuming, from mature
green to fully red stage

EGGPLANT
• Eggplants are harvested when the fruits are 6 to 8
in. in diameter and their color is a glossy purplish
black or white (depending on cultivar).
• As eggplant fruits get older they become dull
colored, soft, and seedy.

BEANS
 Beans are harvested when the pods are filled with
the enlarged seeds.
 The harvested pods must be green and not show
any signs of becoming yellowish.

OKRA
 Okra pods are harvested when they are 3 to 5 in.
long and tender.
 They generally harvested at least every other day
during the peak growing season.
 Over mature pods become woody and are too
tough to eat.

ONIONS
 Bulb onions are harvested when the tops fall over
and begin to turn red/white yellow. Ideal bulb onion
diameter is 2 to 4 in.
 Onions are dug and allowed 1 dry out in the open
sun for a few days to toughen the skin.
 The dried soil of the bulbs is removed by a gentle
brushing.
 The stems are cut, leaving 2 to 3 attached to the
bulb.

PEAS
 Edible-podded cultivars of peas are harvested when
pods are fully developed (about 3 in.) but before
seeds are more than one-half of their full size.
 Regular peas are harvested when the pods are well
rounded and they are fully developed but still fresh
and bright green.

PEPPERS
o Sweet peppers are harvested when the fruits are firm,
crisp, and full-sized (about 4 to 5 in. long).
o Green peppers will turn red or yellow (depending on
the cultivar) if left on the plant.
o Hot peppers are allowed to attain their bright red color
and full flavors while attached to the plant before they
are cut and dried.

POTATOES
 Potatoes are harvested at any size greater than 2 to 3
inches in diameter.
 For full season potatoes, the tubers are harvested
when the plants begin to yellow and die down.
 Exposure of tubers to sunlight is avoided or the
tubers will turn green and become non-edible.

PUMPKINS
 Pumpkins and winter squash are harvested when
they are full size
 The rind should be firm and glossy and the
bottom of the fruit (or ground spot) is cream to
orange.
 The rind is tough and resists puncture from a
thumbnail.
 A 3- to 4-in. portion of stem is left attached to the
fruit.

CUCUMBERS
 Cucumbers are harvested when the fruits are
bright deep green, before any yellow colour
appears.
 The length of the fruit should be 2 to 3 inches

SQUASHES
 Summer squash is harvested when the fruit is soft.
Long-fruited cultivars are harvested when 1% inch in
diameter and 4 to 8 inch long.
 Winter squash is harvested when the fruit is mature.
 Mature fruit are firm and glossy and not easily
punctured by a thumbnail.
 The portion of the fruit that contacts the soil is cream
to orange when mature.

WATERMELONS
 Watermelon fruits are harvested when they are ripe.
 Ripe watermelons produce a dull sound rather than a
sharp, metallic sound when thumped.
 Other indicators are a deep yellow rather than white
color where the melon touches the ground (ground
spot), brown tendrils on the stem near the fruit, and a
rough, slightly ridged feel to the skin surface.

MUSKMELONS
 Muskmelons are harvested when the stem slips
easily from the fruit with a gentle tug.
 Another indicator of ripeness for certain cultivars
is when the netting on skin becomes rounded and
the flesh between the netting turns from a green
to a tan color.

CARROTS
 Carrots are harvested when the roots are 1 in. in
diameter.
 The largest roots generally have the darkest tops.

TURNIPS
 Turnip roots are harvested when they are 2 to 3 in. in
diameter
 The tops can be used as greens when the leaves are
3 to 5 in. long.

RADISHES
 Radishes are harvested when the roots reach 1 inch
in diameter (Indian and Chinese radishes grow
much larger).
 The shoulders of radish roots often appear through
the soil surface when they are mature.
 If left in the ground too long they will become tough
and woody.

SPINACH
o Spinach is harvested by cutting all the leaves off at
the base of the plant, when they are 4 to 6 in. long.
o Alternately, the entire plant may be harvested

Maturity indices of fruits and vegetables

Maturity indices of fruits and vegetables

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