Everything you need to know about guava tree cultivation, growth and production. Learn about:- 1. Introduction to Guava Tree 2. Climate and Soil Required for Growing Guava Tree 3. Propagation 4. Planting 5. Training and Pruning 6. Manuring and Fertilization 7. Weed Control 8. Harvesting and Postharvest Management 9. Varieties 10. Uses.
Contents:
- Introduction to Guava Tree
- Climate and Soil Required for Growing Guava Tree
- Propagation of Guava
- Planting of Guava
- Training and Pruning of Guava
- Manuring and Fertilization of Guava
- Weed Control of Guava
- Harvesting and Postharvest Management of Guava
- Varieties of Guava
- Uses of Guava
1. Introduction to Guava Tree:
Guava (Psidium guajava) is a very popular fruit. It belongs to the myrtle family (Myrtaceae), is almost universally known by its common English name or its equivalent in other languages. The fruits are round or oval, and are eaten as a fresh fruit at two stages- mature green, where the taste is like a sweet apple having white flesh; or fully ripe.
At the hilly ripe stage, the flesh can be white to bright red with light yellow skin. In Spanish, the tree is guayabo, or guayavo, the fruit guayaba or guyava.
The French call it goyave or goyavier; the Dutch, guyaba, goeajaaba; the Surinamese, guave or goejaba; and the Portuguese, goiaba or goaibeira. Hawaiians call it guava or kuawa. In Guam it is abas.
In Malaya, it is generally known either as guava or jambu batu, but has also numerous dialectal names as it does in India, tropical Africa and the Philippines where the corruption, bayabas, is often applied. Various tribal names-pichi, posh, enandi, etc. are employed among the Indians of Mexico and Central and South America.
The guava has been cultivated and distributed by man, by birds, and sundry 4-footed animals for so long that its place of origin is uncertain, but it is believed to be an area extending from southern Mexico into or through Central America. Apparently it did not arrive in Hawaii until the early 1800’s. Now it occurs throughout the Pacific islands.
The guava fruit is a berry with a thick pericarp and fleshy seed cavity. The fruits are soft when ripe, making postharvest handling difficult and critical. Poor handling of the ripe fruit can result in great losses in the field and factory where decaying and damaged fruits are discarded before processing.
When these ripened fruits are further allowed to be exposed to the hot sun, the guava flesh becomes very soft and mushy. These fruits become difficult to puree in this condition, possibly due to actual chemical breakdown in the tissue.
The flesh color of the fruit is becoming increasing important as the use of coloring dyes in food products is being restricted. Fortunately, in Hawaii, the ‘Beaumont’, selected from the wild, has the desired pink flesh color. Flesh color of guavas from the wild range anywhere from white to yellow to salmon- orange and pink, all of which blend into an unattractive yellow-orange product. Wild guava fruits need to be blended with the pink to produce nectars with acceptable color.
2. Climate and Soil Required for Growing Guava Tree:
Owing to its hardy nature, guava is grown successfully in tropical and subtropical regions up to 1,500 m above mean sea-level. Best quality guavas are obtained where low night temperatures (10°C) prevail during winter season.
The guava tolerates and can withstand strong prevailing winds or winds of hurricane velocities. Its root system is a fine mat supporting the tops and requires a tremendous horizontal wind force to uproot the tree. In addition, the guava wood is strong and flexible and pliable, enabling the tree and its branches to bend in a whip like fashion in a strong wind.
Growth and fruit production can be reduced when the trees are grown in areas with constant prevailing winds of 10-15 miles an hour. In such situations, the trees will grow and develop away from the wind with short, stubby limbs facing the wind.
The guava thrives in both humid and dry climates. In India, it flourishes up to an altitude of 3,280 ft (1,000 m); in Jamaica, up to 3,906 ft (1,200 m); in Costa Rica, to 4,590 ft (1,400 m); in Ecuador, to 7,540 ft (2,300 m). It can survive only a few degrees of frost. Young trees have been damaged or killed in cold spells at Allahabad, India.
Older trees, killed to the ground, have sent up new shoots which fruited 2 years later. The guava requires an annual rainfall between 40 and 80 in (1,000-2,000 mm); is said to bear more heavily in areas with a distinct winter season than in the deep Tropics.
The guava seems indiscriminate as to soil, doing equally well on heavy clay, marl, light sand, gravel bars near streams, or on limestone; and tolerating a pH range from 4.5 to 9.4. It is somewhat salt-resistant. Good drainage is recommended but guavas are seen growing spontaneously on land with a high water table too wet for most other fruit trees.
Maximum concentration of its feeding rots is available up to 25 cm soil depth. Thus the top soil should be quite rich to provide enough nutrients for accelerating new growth which bears fruits.
3.
Propagation of Guava:
Guava is propagated both by seeds and vegetatively. But vegetative propagation is commercially followed.
1. Seed Propagation:
Guava seeds remain viable for many months. They often germinate in 2 to 3 weeks but may take as long as 8 weeks. The propagation of guava through seeds should not be encouraged because the seedlings have long juvenile phase, give lower yields and bear poor quality fruits. But the seedlings serve as rootstock material for grafting or budding.
Pretreatment with sulfuric acid, or boiling for 5 minutes, or soaking for 2 weeks, will hasten germination. Seedlings are transplanted when 2 to 30 in (5-75 cm) high and set out in the field when 1 or 2 years old. Inasmuch as guava trees cannot be depended upon to come true from seed, vegetative propagation is widely practiced.
2. Vegetative Propagation:
In northern India, guava is propagated by inarching, giving a very high percentage of success during rainy season. But inarching is cumbersome and gives limited number of plants from the mother plant.
In India and elsewhere, the tree has been grown from root cuttings. Pieces of any roots except the smallest and the very large, cut into 5 to 10 in (12.5-20 cm) lengths, are placed flat in a prepared bed and covered with 2 to 4 in (5-10 cm) of soil which must be kept moist. Or one can merely cut through roots in the ground 2 to 3 ft (0.6-0.9 m) away from the tree trunk; the cut ends will sprout and can be dug up and transplanted.
3. Layering Propagation:
Layering is being commercially followed in the southern and western India with very good results. Air-layers of selected clones are allowed to grow 3 to 5 years and are then sawn off close to the ground. Then a ring of bark is removed from each new shoot; root-inducing chemical is applied. Ten days later, the shoots are banked with soil to a height 4 to 5 in (10-12.5 cm) above the ring.
After 2 months, the shoots are separated and planted out. In India, air-layering and inarching have been practiced for many years. However, trees grown from cuttings or air-layers have no taproot and are apt to be blown down in the first 2 or 3 years. For this reason, budding and grafting are preferred.
4. Propagation by Budding:
Budding is another method of propagation, though it has been adopted only on a limited scale in some parts of the country. This kind of propagation is suitable for area where the atmospheric humidity is high. The main problem encountered in this method is disbudding of rootstock making it labour- intensive.
Among the various methods of budding-shield, forkert, patch and chip – the patch budding is ideal giving highest percentage of success. Time of budding varies from locality-to-locality.
5. Stooling:
Stooling is the easiest and cheapest method of guava propagation. The self- rooted plants (cuttings or layers) are planted 0.5 m apart in the stooling bed and are allowed to grow for about 3 years. Then these are cut down at the ground level in March. New shoots emerge on the beheaded stumps. A 30 cm wide ring of bark is removed for the base of each shoot rubbing the cambium of the exposed portion in May.
All the shoots are mounded with the soil to a height of 30 cm. The soil is covered with mulch to conserve the moisture. After a period of 2 months of onset of monsoon, the shoots are detached from the mother plant at ringed portion and planted in the nursery. The shoots are headed back to maintain the root and shoot balance before planting in the nursery.
4. Planting of Guava:
Guava trees are planted too close during the rainy season by adopting square planting system. Optimum distance between the trees should be at least 10 m. Planting 5 m apart is possible if the trees are hedged. The yield per tree will be less but the total yield per land area will be higher than at the wider spacing. Some recommend setting the trees 2.4 m apart in rows 7.3 m apart and removing every other tree as soon as there is overcrowding.
Where mass production is not desired and space is limited, guava trees can be grown as cordons on a wire fence. Rows should always run north and south so that each tree receives the maximum sunlight. Exudates from the roots of guava trees tend to inhibit the growth of weeds over the root system.
The planting design of any crop should be determined only after considering the tree’s growth habit, its response to pruning, harvesting method, and other cultural methods to be used in the care of the orchard.
The field is prepared in summer season by ploughing, leveling and removing weeds. The size of the pits is 1 m x 1 m x 1 m filled with a mixture of farmyard manure and soil with irrigation facilities. Guava is commercially planted at a distance of 5 to 8 m. The exact planting distance is decided according to variety, soil fertility and availability of irrigation facilities.
High- density planting reduces total soluble solids, sugars and ascorbic acid in the fruits and causes erect growth of branches making the plant tall and compact but gives higher yield/unit area in early years of fruiting. Such condition of planting also increases titratable acidity. The lower plant population results in the spread of crown.
5. Training and Pruning of Guava:
Guava trees are pruned to increase yield and to reduce the total cost of field operations by eliminating obstacles and branch hazards, allowing easier movement around the trees. Fortunately, the guava can be pruned and trained to any dimension or pattern the grower wishes.
Traditionally, no pruning is done in guava because the plant bears heavily even without it. Light pruning is always recommended to develop a strong framework, and suckers should also be eliminated around the base. Experimental heading-back has increased yield in some cultivars in Puerto Rico.
In Palestine, the trees are cut back to 2 m every other spring to facilitate harvesting without ladders. Fruits are borne by new shoots from mature wood. If trees bear too heavily, the branches may break. Therefore, thinning is recommended and results in larger fruits. But no pruning results in the formation of narrow crotches, limb breakage due to heavy fruit load and overcrowding.
Guava trees grow rapidly and fruit in 2 to 4 years from seed. They live 30 to 40 years but productivity declines after the 15th year. Orchards may be rejuvenated by drastic pruning. In Maharashtra, bending of horizontal branches is practised to some extent by tying the branches of 2 adjoining plants to increase fruiting in young plants but it is labour-intensive and creates hindrances in cultural operations.
To check the overcrowding and to control the plant height, the terminal shoots on the periphery may be headed back at about 40 cm level in alternate years. Pruning is recommended after harvesting or in spring. Summer pruning may damage the plant by sun burning.
To maximize production, tree limbs must be developed to cover the land area as completely as possible. This can be done in time by pruning and tree training. However, a better way to do this is initially to reduce the “blank” areas between the trees in the orchard by planting them on an equilateral triangle (quincunx) system and at a desired distance between trees rather than on a square design.
6. Manuring and Fertilization of Guava:
Guava trees respond to a complete fertilizer mix applied once a month during the first year and every other month the second year (except from mid- November to mid-January) at the rate of 8 oz (227 g) per tree initially with a gradual increase to 24 oz (680 g) by the end of the second year. Nutritional sprays providing copper and zinc are recommended thrice annually for the first 2 years and once a year thereafter.
In India, flavor and quality of guavas has been somewhat improved by spraying the foliage with an aqueous solution of potassium sulfate weekly for 7 weeks after fruit set.
Leaf analysis can be used a guide to guava fertilization.
Recommended leaf values are:
The table gives the elemental values as % or parts per million (ppm) of the oven- dried leaf material.
The index leaf is the four leaves in a whorl of leaves of an actively growing major terminal, counting the first expanding young leaf in the whorl as No. 1. A 10-leaf sample should be taken at random from 10 trees in an area where the information is desired. If plant growth and appearance in the area are uniform, one sample is sufficient. More samples from an area are suggested if differences are visible.
If deficiencies are indicated by symptoms or leaf analysis, corrective measures should be taken immediately. If not, because of the crop cycling procedure, whatever fertilizer program is suggested should be applied after the completion of the current crop for the benefit of the succeeding crop.
Recent preliminary data and observations indicate that calcium is related to the firmness of fruits and blossom-end rot of matured fruits. Leaf calcium level to correct this condition appears to be 1.25% or higher.
The most economical calcium sources are calcium carbonate from beach sand, calcium oxide from burnt lime, and calcium hydroxide from hydrated lime. These can be plowed in before planting to supply the need for calcium. For magnesium needs, magnesium oxide or dolomite should be used.
Time of fertilizer application depends on the crop taken and the region. In north India, fertilizer is given in the first week of May for rainy season crop and in first week of July for winter season crop. In West Bengal, fertilizers are applied in 2 equal split doses, one in January and the other in August.
At Bangalore, full K and 70% N are applied in June and full P and 30% in September. Since 48% of feeder roots of guava are found in the surface soil up to 25 cm, depth, the fertilizer should be placed in 25 cm trenches 1 m away from the trunk for better uptake.
Sometimes guava suffers a deficiency which is characterized by reduction in leaf size, intervenial chlorosis, suppression of growth and dieback of leaders. It can be corrected by spraying of ZnSO4 (0.45 kg) and hydrated lime (0.32 kg) in water (33 litre). Bronzing is another common problem in guava. It is caused by the deficiency of B, Zn, N, P and K due to low soil pH.
The soluble P level of leaves is a better index for bronzing. Guava Lucknow 49 is more susceptible than Allahabad Safeda. It can be reduced by improving the soil pH and treating the soil with N, P, K and Zn at 200, 80, 150 and 80 g/year respectively, or fortnightly foliar spraying of these nutrients each at 2% for 4 months.
Aftercare:
Guava plants do not require much care after planting. The weeds are removed by shallow cultivation. Green manuring should be done during rainy season and clean cultivation during rest of the year. Leguminous crops can be grown as intercrops during first 3 years of planting to obtain more income and to increase the N content of the soil.
Both rainy and winter season crops are very heavy compared with spring crop. Fruit quality of the winter crop is best. Therefore, winter crop is preferred over the rainy season crop. In northern India, normally hot and dry summers along with low soil moisture do not allow summer flowers to set the fruits.
But in mild summer and normal soil moisture, the summer flowers set fruits for rainy season crop which is known for its poor quality fruits and severe incidence of fruit fly and fruit-borer. The practice of taking winter crop instead of rainy season crop is known as crop regulation.
The rainy season crop can be removed by spraying of urea (10%) on Allahabad Safeda and 20% on Lucknow 49 at the time of peak flowering in summer season. Other methods of removing rainy season crop are hand removal of flowers and fruit, spraying of bio-regulators, root exposure, withholding irrigation and pruning of 3/4th of flower-bearing shoots are either costlier or impractical or ineffective.
The tree is drought-tolerant but in dry regions lack of irrigation during the period of fruit development will cause the fruits to be deficient in size. In areas receiving only 38-50 cm rainfall annually, the guava will benefit from an additional 2,460 cm applied by means of 8 to 10 irrigations, one every 15-20 days in summer and one each month in winter.
Guava is mostly grown under rainfed condition and irrigation is rarely practised wherever this facility is available. However, irrigation enhances the yield of guava by making the plant more vigorous and increasing the fruit set. Irrigation is especially desirable after planting for survival of the plants and thereafter for 2-3 years to obtain early good growth. Irrigation of fruiting plants depends upon the adoption of a particular cropping pattern.
For the whole year, cropping pattern which is commercially adopted all over the country except the northern region, irrigation is given during summer and autumn season and for the rainy season crop, the irrigation is essential during summer season.
Normally, winter season cropping pattern is adopted in north India which requires fortnightly irrigation during October-November. Irrigation is given to make the soil of root zone moist; thus heavy irrigation is unnecessary. The fruit quality of guava is adversely affected by high soil moisture content during harvesting.
7. Weed Control of Guava:
Guava is hardy, aggressive, and a perennial that has only recently become a cultivated crop. It is capable of growing and fruiting under severe competition from other plants. Consequently, weed control efforts in a guava orchard may be only minimal to begin with since control expenditure can become too high. There are several ways weeds can be controlled, however.
i. Minimal Control:
Eliminate only tall weeds by hand that grow into the crown of the tree or in the space between trees. Eventually, however, such minimal management will result in an unproductive orchard unless further efforts in weed control is expended as cash flow develops.
ii. Surface Mulching:
Mulching at the base of trees can be done very inexpensively using black polyethylene sheets, cinder materials, or organic materials such as wood shavings. The latter two materials should be applied thick enough to prevent weed growth yet permit rainwater penetration to the root area.
Black polyethylene sheets prevent soils surface evaporation and tend to produce water under the sheets through condensation, supporting tree growth besides affording weed control.
iii. Mowing:
Mowing throughout the orchard with an off-set tow mower is a good method to eliminate tall, woody plants or grasses. However, this method can become expensive since the weeds at the base of the trees will consumer a large portion of the applied fertilizer, depending on the application technique and available water. In such situations, the total amount of applied fertilizer needs to be increased.
iv. Herbicide and Mowing:
Herbicide around the base of trees with only occasional mowing in the areas between trees is a good method. The herbicide area can be gradually expanded into the mowing area as the trees become larger and older. This method is probably the most economical to use.
The use of chemical weed control may initially appear expensive, but when properly applied, it can become a good economical method to achieve the gradual elimination of weed seeds and vegetative propagules.
8. Harvesting and Postharvest Management of Guava:
Guavas are harvested throughout the year (except during May and June) in one or the other region of the country. However, peak harvesting periods in north India are August for rainy season crop, November-December for winter season crop and March-April for spring season crop. In the mild climatic conditions of the other parts of the country, the peak harvesting periods are not so distinct.
Guava fruits develop best flavour and aroma only when they ripen on tree. In most of the commercial varieties, the stage of fruit ripeness is indicated by the colour development which is usually yellow. For local market, fully yellow but firm fruits are harvested, whereas half yellow fruits should be picked for distant markets. The fruits are harvested selectively by hand along with the stalk and leaves.
Quality Characteristics and Criteria:
Skin color is used to measure maturity and ripeness. Size and shape are other important quality criteria. Fruit should be free of defects, decay and insect damage. Some varieties have only a few seeds, while others have a large cavity full of seeds. Fruit range from 9 to 12 cm (3.5 to 4.7 in) in size.
Ripening of guava starts on the tree and continues even after harvest. It is accelerated in rainy season due to high temperature and slows down in winter season due to low temperature. The fruits are packed in baskets made from locally available plant material. For distant markets, wooden or corrugated fibreboard boxes are used along with good cushioning materials – paddy straw, dry grass, guava leaves or rough paper.
Good ventilation is necessary to check buildup of heat. Guava is a delicate fruit requiring careful handling during harvesting and transporting. The fruits should reach the consumer in a firm condition.
Because of their perishable nature, guavas are disposed off immediately after harvesting in the local market and a very small quantity is sent to distant markets. Since fruits are sold at a cheaper price and are available for a very long period of the year, they are not kept in cold storage.
However, shelf-life of guava can be extended up to 20 days by keeping them at low temperature of 5°C and 75-85% relative humidity. It can also be stored for about 10 days at room temperature (18°-23°C) in polybags providing a ventilation of 0.25%.
Maturity Indices:
Guava fruits are picked at the mature-green stage (color change from dark- to light-green) in some countries where consumers eat them at that stage. In countries where consumers prefer ripe guava, the fruits are picked at the firm- yellow to half-ripe (softer) stage for long-distance transport or at the fully-ripe (yellow and soft) stage for local markets.
Harvest stage depends on variety and the stage at which fruit are to be eaten. If eaten green, fruit should be harvested at the mature, firm stage without any signs of ripening. Fruit to be consumed soft and ripe are harvested when they show some sign of color change from green to yellow, as well as initial softening.
Later harvesting, when fruit are riper, can lead to a high number of fruit fly stings and later larvae in the flesh. SSC can vary from 3% in green fruit to > 10% in ripe fruit, and the TA from 0.2 to 1.5%; cultivars vary greatly in sweetness and acidity. There is seasonal variation in acidity in some cultivars.
Quality Indices:
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 100 g fresh weight) and some cultivars are also rich in vitamin A.
i. Grades, Sizes and Packaging:
Commonly shipped in a 4.5 kg (10 lb) single layer cartons with foam sleeves or wrapping to prevent injury.
ii. Pre-Cooling Conditions:
Room-, forced-air or hydro-cooling should be used to about 10 °C (50 °F).
iii. Optimum Storage Conditions:
Mature green and partially ripe fruit can be held for 2 to 3 weeks at 8 to 10 °C (46 to 50 °F). Ripe, soft fruit can be held about 1 week at 5 to 8 °C (41 to 46 °F). RH of 90 to 95% is recommended. Shelf-life is about 7 days when stored at 20 °C (68 °F).
iv. Optimum Temperature:
8-10°C (46-50°F) for mature-green and partially- ripe guavas (storage potential = 2-3 weeks) 5-8 °C (41-46°F) for fully-ripe guavas (storage potential = 1 week).
v. Optimum Relative Humidity:
90-95%.
vi. Retail Outlet Display Considerations:
Display chilled if fruit are fully ripe, or at 8 to 10 °C (46 to 50 °F) if green and if ripening is to be avoided.
vii. Chilling Sensitivity:
Symptoms include skin scald, pitting and a failure to ripen if mature green or partially ripe when chilled. Browning of the flesh can occur. Decay incidence and severity increases with chilling injury. Ripe, soft fruit can be held at 5 °C (41 °F), as they are less sensitive to chilling injury.
Rates of Ethylene Production:
Guava is a climacteric fruit. Rates of respiration and ethylene production depend upon cultivar and maturity/ripeness stage. Ethylene production at 20 °C (68 °F) ranges from 1 to 20 μl /kg/hr. Rates vary from 1 to 20 μL kg-1 h-1 at 20 °C and show a climacteric pattern of respiration. Rates vary with variety and stage of ripeness. Ripening is accelerated by exposure to ethylene (100 ppm, 24 h). Immature fruit do not ripen properly and develop a “gummy” texture.
Responses to Ethylene:
Ethylene at 100 ppm for 1-2 days can accelerate ripening of mature-green guavas to full-yellow stage at 15-20°C (59-68°F) and 90-95% relative humidity. This treatment results in more uniform ripening, which is more important for guavas destined for processing. Immature-green guavas do not ripen properly and develop ‘gummy’ texture.
Responses to Controlled Atmospheres (CA):
The limited research on guava indicates that 2-5% oxygen levels may delay ripening of mature-green and partially-ripe guavas kept at 10 °C (50 °F). Tolerance to elevated carbon dioxide levels has not been determined.
Short- term treatment (24 h) with 10% O2 + 5% CO2 before storage in air at 4 °C (39 °F) for 2 weeks delays color development and reduces chilling injury, compared to fruit held in air. MAP in polyethylene bags and use of wax coatings delays ripening/softening. Skin blackening is a problem when some wax coatings are applied.
9.
Varieties of Guava:
The varietal characteristics in guava are not as distinct as found in majority of other fruits. Formerly, round and pear-shaped guavas were considered separate species – P. pomiferum L. and P. pyriferum L.- but they are now recognized as mere variations. Small, sour guavas predominate in the wild and are valued for processing.
In India much attention is given the characteristics of local and introduced guava cultivars and their suitability for various purposes.
Among common white-fleshed cultivars are:
A seedless type at Poona, India, was found to be a triploid with 33 chromosomes in place of the usual 22.
Other white-fleshed guavas with poor canning qualities are – ‘Dharwar’, ‘Mirzapuri’, ‘Nasik’, ‘Sindh’, and ‘White Supreme X Ruby’.
Among other Indian cultivars are – Banaras, Dholka, Hasijka, Kaffree, and Wickramasekara. The latter is a small fruit and poor bearer.
10. Uses of Guava:
Food Value:
Raw guavas are eaten out-of-hand, but are preferred seeded and served sliced as dessert or in salads. More commonly, the fruit is cooked and cooking eliminates the strong odor. A standard dessert throughout Latin America and the Spanish-speaking islands of the West Indies is stewed guava shells (cascos de guayaba), that is, guava halves with the central seed pulp removed, strained and added to the shells while cooking to enrich the syrup.
The canned product is widely sold and the shells can also be quick-frozen. They are often served with cream cheese. Sometimes guavas are canned whole or cut in half without seed removal.
Bars of thick, rich guava paste and guava cheese are staple sweets, and guava jelly is almost universally marketed. Guava juice, made by boiling sliced, unseeded guavas and straining, is much used in Hawaii in punch and ice cream sodas.
A clear guava juice with all the ascorbic acid and other properties undamaged by excessive heat, is made in South Africa by trimming and mincing guavas, mixing with a natural fungal enzyme (now available under various trade names), letting stand for 18 hours at 120° to 130° F (49°-54°C) and filtering.
It is made into syrup for use on waffles, ice cream, puddings and in milkshakes. Guava juice and nectar are among the numerous popular canned or bottled fruit beverages of the Caribbean area. After washing and trimming of the floral remnants, whole guavas in syrup or merely sprinkled with sugar can be put into plastic bags and quick-frozen.
There are innumerable recipes for utilizing guavas in pies, cakes, puddings, sauce, ice cream, jam, butter, marmalade, chutney, relish, catsup, and other products. In India, discoloration in canned guavas has been overcome by adding 0.06% citric acid and 0.125% ascorbic acid to the syrup. For pink sherbet, French researchers recommend 2 parts of the cultivar ‘Acid Speer’ and 6 parts ‘Stone’. For white or pale-yellow sherbet, 2 parts ‘Supreme’ and 4 parts ‘Large White’.
In South Africa, a baby-food manufacturer markets a guava- tapioca product, and a guava extract prepared from small and overripe fruits is used as ascorbic-acid enrichment for soft drinks and various foods.
Dehydrated guavas may be reduced to a powder which can be used to flavor ice cream, confections and fruit juices, or boiled with sugar to make jelly, or utilized as pectin to make jelly of low-pectin fruits. India finds it practical to dehydrate guavas during the seasonal glut for jelly-manufacture in the off-season. In 1947, Hawaii began sea shipment of frozen guava juice and puree in 5-gallon cans to processors on the mainland of the United States.
Since 1975, Brazil has been exporting large quantities of guava paste, concentrated guava pulp, and guava shells not only to the United States but to Europe, the Middle East, Africa and Japan.
Canned, frozen guava nectar is an important product in Hawaii and Puerto Rico but may be excessively gritty unless stone cells from the outer flesh and skin are reduced by use of a stone mill or removed by centrifuging.
In South Africa, guavas are mixed with cornmeal and other ingredients to make breakfast-food flakes.
Green mature guavas can be utilized as a source of pectin, yielding somewhat more and higher quality pectin than ripe fruits.
Ascorbic acid is present mainly in the skin, secondly in the firm flesh, and little in the central pulp-varies from 56 to 600 mg. It may range up to 350-450 mg in nearly ripe fruit. When specimens of the same lot of fruits are fully ripe and soft, it may decline to 50-100 mg.
Canning or other heat processing destroys about 50% of the ascorbic acid. Guava powder containing 2,500- 3,000 mg ascorbic acid was commonly added to military rations in World War II. Guava seeds contain 14% of aromatic oil, 15% protein and 13% starch. The strong odor of the fruit is attributed to carbonyl compounds.
Other Uses:
1. Wood:
The wood is yellow to reddish, fine-grained, compact, moderately strong, weigh 650-750 kg per cubic meter; is durable indoors; used in carpentry and turnery. Though it may warp on seasoning, it is much in demand in Malaya for handles; in India, it is valued for engravings. Guatemalans use guava wood to make spinning tops, and in El Salvador it is fashioned into hair combs which are perishable when wet. It is good fuel-wood and also a source of charcoal.
2. Leaves and Bark:
The leaves and bark are rich in tannin (10% in the leaves on a dry weight basis, 11-30% in the bark). The bark is used in Central America for tanning hides. Malayans use the leaves with other plant materials to make a black dye for silk. In southeast Asia, the leaves are employed to give a black color to cotton; and in Indonesia, they serve to dye matting.
3. Wood Flowers:
In Mexico, the tree may be parasitized by the mistletoe, Psittacanthus calyculatus Don, producing the rosette-like malformations called “wood flowers” which are sold as ornamental curiosities.
4. Medicinal Uses:
The roots, bark, leaves and immature fruits, because of their astringency, are commonly employed to halt gastroenteritis, diarrhea and dysentery, throughout the tropics. Crushed leaves are applied on wounds, ulcers and rheumatic places, and leaves are chewed to relieve toothache.
The leaf decoction is taken as a remedy for coughs, throat and chest ailments, gargled to relieve oral ulcers and inflamed gums; and also taken as an emmenagogue and vermifuge, and treatment for leucorrhea.
It has been effective in halting vomiting and diarrhea in cholera patients. It is also applied on skin diseases. A decoction of the new shoots is taken as a febrifuge. The leaf infusion is prescribed in India in cerebral ailments, nephritis and cachexia. An extract is given in epilepsy and chorea and a tincture is rubbed on the spine of children in convulsions. A combined decoction of leaves and bark is given to expel the placenta after childbirth.
The leaves, in addition to tannin, possess essential oil containing the sesquiterpene hydrocarbons caryophyllene, β -bisabolene, aromadendrene, β – selinene, nerolidiol, caryophyllene oxide and sel-11-en-4x-ol, also some triterpenoids and β -sitosterol. The bark contains tannin, crystals of calcium oxalate, ellagic acid and starch. The young fruits are rich in tannin.