Maturity indices and quality characteristics of fruit crops
Authors: Panchal Bhakti B., Dr. N. B. Patel, Gurjar Tulsi D. and Dr. R. V. Tank
ASPEE College of Horticulture and Forestry,
Navsari Agriculture University, Navsari- 396 450, Gujarat, India
E-mail: bhakti.b.panchal@gmail.com


Introduction
• Maturation is the stage of development leading to the physiological maturity (when a plant or plant parts will continue ontogeny even if detached) or horticultural maturity (when a plant or plant parts possesses the pre-requisites for utilization by the consumer for a particular purpose).
• Maturity indices help in deciding that when a given commodity should be harvested to provide some marketing and to ensure the attainment of acceptable eating quality to the consumer.
• Fruits are picked at the wrong stage of maturity may develop physiological disorders in storage and may exhibit poor dessert quality.
• For selecting the harvest maturity of fruits or vegetables it should be kept in mind that harvested commodity should have its peak acceptable quality (nontoxic, size, appearance, and flavor with adequate shelf life) (Thompson, 1996).
• Quality indices consist of a combination of visual appearance, texture & flavor.

1) Mango
Maturity indices:
• Tapka stage
• Specific gravity (1.0-1.02 for Alphonso & less than 1.0 for dashehari).
• White powdery like appearance on skin of mature mango.
• Change in fruit shape (fullness of the cheeks)
• Days to fruit set (110-125 days for Alphonso and Pairi).
• Change in skin color from dark-green to light-green to yellow (in some cultivars). Red color on the skin of some cultivars is not a dependable maturity index.
• TSS 12-15 %
• Change in flesh color from greenish-yellow to yellow to orange.
Quality characteristic
• Uniformity of shape and size; skin color (depending on cultivar); flesh firmness.
• Freedom from decay and defects, including sunburn, sap burn, skin abrasions, stem-end cavity, hot water scald, chilling injury, and insect damage.
• Changes associated with ripening include starch to sugar conversion (increased sweetness), decreased acidity and increased carotenoids and aroma volatiles.
• There are large differences in flavor quality (sweetness, sourness, and aroma) and textural quality (fiber content) among cultivars.

2) Banana
Maturity indices
• Degree of fullness of the fingers i.e., disappearance of angularity in a cross section.
• Skin and pulp ratio (1.20:1.40 for Dwarf Cavendish).
• Drying of plant parts.
• Acid content 0.25%
• Starch index.
• Days to fruit set (90 days for Dwarf Cavendish).
• Bananas are harvested mature-green and ripened upon arrival at destination markets.
Quality characteristic
• Maturity (the more mature the better the quality when ripe)
• Finger length (depending on intended use and demand for various sizes).
• Freedom from defects, such as insect injury, physical damage, scars, and decay.
• As bananas ripen their starch content is converted into sugars (increased sweetness). Other constituents that influence flavor include acids and volatiles.

3) Citrus
Maturity indices :
• All citrus are non-climacteric fruit, meaning that they ripen gradually over weeks or months and are slow to abscise from the tree.
• External color changes during ripening, but is a function of climate more than ripeness, and a poor indicator of maturity.
• Juice content (35-50%)
• TSS 12-14% for mandarin and for sweet orange 10-12%
• By acidity (mandarin 0.4%, sweet orange 0.3%)
• The best indices of maturity for citrus are internal: o Brix (sugar), acid content, and the o Brix/acid ratio (mandarin 12-14o brix, sweet orange 12o brix).

4) Papaya
Maturity indices
• Change of skin color from dark-green to light-green with some yellow at the blossom end (color break).
• Papayas are usually harvested at color break to 1/4 yellow for export or at 1/2 to 3/4 yellow for local markets.
• TSS 7-11%
• A minimum soluble solids of 11.5% is required
• Quality characteristic
• Papayas picked 1/4 to full yellow taste better than those picked mature - green to 1/4 yellow because they do not increase in sweetness after harvest.
• Uniformity of size and color; firmness; freedom from defects such as sunburn, skin abrasions, pitting, insect injury, and blotchy coloration; freedom from decay.

5) Guava
Maturity indices
• Guava fruits are picked at the mature-green stage (color change from dark- to light-green).
• Specific gravity 1.01-1.02
• TSS 12-14 %
• Quality characteristic
• Color is a good indicator of ripeness stage
• Size and shape may be important in some markets
• Freedom from defects, insects, and decay
• Firmness and extent of gritty texture due to the presence of stone cells (sclereids)
• Flesh color depends on cultivar and can be white, yellow, pink, or red
• Amount of seeds in the flesh (the fewer the better)
• Aroma intensity
• Soluble solids and acidity
• Guava is one of the richest sources of vitamin C (200 to 400 mg per 100g fresh weight) and some cultivars are also rich in vitamin A

6) Sapota
Maturity indices
• Fruit with 80% maturity
• Skin color change from light-brown with a tinge of green to light-brown to dark-brown.
• Weight of fruit 65-70 gms
• Flesh yellow streak when scrached with finger nail
• Specific gravity 1.025-1.057.
• Quality characteristic
• Appearance: size, shape (oval), color, freedom from defects, and freedom from decay.
• Firmness (firm-ripe sapotes are preferred).
• Flavor is related to soluble solids content (13-26%) and acidity (0.2-0.3%).

7) Jackfruit
Maturity indices
• Jackfruits can reach very large size (as much as 90 cm long, 50 cm wide, and 25 kg in weight), depending on the cultivar, production area, and the fruit load on the tree.
• Color change from green to yellow to brown is used as an indication of maturity and ripeness stages.
• Optimum harvest for long-distance transport is when the fruit changes color from green to yellowish-green.
• Quality characteristic
• Fruit size
• Shape
• Color
• Freedom from defects (sunburn, cracks, bruises) and decay
• Jackfruits contain 25-30% carbohydrates (fresh weight basis) including about 15-20% starch in unripe fruits that is converted to sugars (sucrose + glucose + fructose) in ripe fruits.
• The unripe fruit is used as a starchy vegetable, either boiled or roasted, and when ripe it is used as a dessert fruit. Average acidity is 0.25% citric acid.
• Jackfruit fruitlets are commonly sold in producing countries as a fresh-cut product.

8) Pineapple
Maturity indices
• Flattening of eyes with slight hollowness at the centre
• Change of shell color from green to yellow at the base of the fruit.
• Specific gravity 0.98-1.02%
• A minimum soluble solids content of 12-14% and a maximum acidity of 1% will assure minimum flavor acceptability by most consumers.
• Quality characteristic
• Uniformity of size and shape, firmness
• Freedom from sunburn, sunscald, cracks, bruising, internal breakdown, endogenous brown spot, gummosis, and insect damage.
• Tops (crown leaves): green color, medium length, and straightness.
• Range of soluble solids = 11-18%; titratable acidity (mainly citric acid) = 0.5-1.6%; and ascorbic acid = 20-65mg/100g fresh weight, depending on cultivar and ripeness stage.

9) Annona
Maturity indices
• Change in skin color from dark-green to light-green or greenish-yellow.
• Days to full bloom (100-115 days).
• Other indicators include appearance of cream color between segments on the skin and increased surface smoothness of the separate fruit carpals.
• Quality characteristic
• Fruit size, color, absence of defects and decay, firmness (annona fruits are relatively soft fruits and must be handled with care to minimize bruising).
• Cherimoya, atemoya and sweetsop have high concentrations of sugars (14-15% when ripe) and moderate acidity (0.4-0.7% when ripe). They are good sources of vitamin C (45-60mg/100g) and potassium (250-500mg/100g edible portion).

10) Aonla
• There are number of factors affect the maturity of fruits such as location, variety, climate, and season, nutrition, soil type and moisture, etc.
• The maturity indices of aonla fruits are change of seed colour from creamy white to brown black.

11) Pomegranate
Maturity indices
• External red colour (depending on cultivar)
• Red colour of juice
• Acidity of juice below 1.85%
Quality characteristic
• Freedom from growth cracks, cuts, bruises, and decay.
• Skin colour and smoothness.
• Flavor depends on sugar/acid ratio which varies aming cultivars. A suitable solids content above 17% is desirable.
• Tannin content below 0.25% is desirable.

12) Ber
Maturity indices:
• Ber mature 150-175 days after flowering.
• Green to golden yellow colour
• Seed/stone ratio: 12 to 18
• TSS 15-18%


References:

1. Handbook of fruit production by S. Prasad & U. Kumar.
2. Post Harvest Handling and Processing of Fruits and Vegetables
3. A textbook of pomology by T. K. Chattopadhayay
4. Glaustas horticulture by P. Muthukumar & R. Selvakumar


About Author / Additional Info:
I am the student of 2nd semester Ph. D. â€"Horticulture (Agriculture). Main subject of my research work on vegetables and fruit crops.