• Varieties
• Cultivation Practices
• Plant Protection
• Harvesting & Processing 
• Alternative Uses & Waste Utilisation

The arecanut palm (Areca catechu L.) is one of the important commercial crops of India. The crop is mainly grown in the states of Kerala, Karnataka, Tamil Nadu, Assam, West Bengal, Meghalaya, Maharashtra, and Andaman & Nicobar group of Islands. The economic produce is the fruit called betelnut or 'supari' which is used mainly for mastigatory purpose. Arecanut is an essential ingredient of ‘gutka’ and ‘pan masala.’ It is consumed both as a raw/ripe nut (adaka or kacha tamul), as dried ripe nut (chali supari) and as semi-mature, cut and processed varieties `Bateldike’ or `Kalipak’.

Arecanut or betlelnut is an extensively cultivated tropical palm. It is a tall-stemmed, erect, reaching varied height, depending upon the environmental conditions.

Climate & Soil

Arecanut grows well within the temperature range of 14ºC and 36ºC and is adversely affected by temperatures below 10ºC and above 40ºC. Extremes of temperature and wide diurnal variations are not conducive for the healthy growth of the palms. It can be grown in areas receiving annual rainfall of 750 mm to 4,500 mm. In areas where there is prolonged dry spell, the palms are irrigated. Due to its susceptibility to low temperature, a good crop of arecanut cannot be obtained at an altitude of more than 1000 m MSL.

The largest area under the crop is found in gravelly laterite soils of red clay type. It can also be grown on fertile clay loam soils. Sticky clay, sandy, alluvial, brackish and calcareous soils are not suitable for arecanut cultivation.

Varieties

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Distinguishing characters of promising cultivars and released varieties of arecanut

Cultivation Practices

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Arecanut is propagated only by seeds. Being a perennial crop, adequate care should be taken in selecting the planting material. There are four steps in selection and raising of arecanut seedlings viz., selection of mother palms, selection of seed nuts, germination and raising the seedlings and selection of seedlings.

Selection of site:

Select sites with deep well drained soil without high water table. Provide adequate irrigation facilities

Selection of mother palms:

The criteria for the selection of mother palm are; early bearing, regular bearing habit, semi tall to dwarf stature, large number of leaves on the crown, shorter internodes and high fruit set.

Selection of seed nut:

Fully ripened nuts from middle bunches having weight of above 35 g should be selected during mid season. The nuts selected should float vertically with calyx-end pointing upwards when allowed to float on water. These nuts produce the seedlings of greater vigour.

Nursery techniques:

         Sow selected seed nuts soon after harvest in nursery bed with stalk-end up and with a spacing of 5-6 cm. Cover the seed nuts with sand and irrigate daily. Transplant 90 days old sprouts having 2-3 leaves to the secondary nursery. Prepare secondary nursery beds of 150 cm width and convenient length. Apply cattle manure @ 5 t ha-1 as basal dose. Transplant sprouts at a spacing of 30 cm x 30 cm. Provide shade by growing banana, Coccinia indica etc or by means of artificial pandal. Plant banana in advance at a spacing of 2.7 m x 3.6 m when it is grown as a shade crop. Provide irrigation during hot and dry periods and drainage during monsoon. Periodical weeding and mulching are necessary.

Selection of seedlings:

Select good seedlings for transplanting in the main field when they are 12-18 months old. Selection of seedlings can be based on the selection index. Multiplying leaf number by 40 and subtracting the seedling height gives the selection index. Select seedlings with higher selection index values.

Example: Seedling height = 90 cm, Leaf number = 5 Selection index = (5 x 40)–90 = 110 (If for instance, index values range between 50 and 150, select seedlings with higher values to the extent possible). Uproot the seedlings with the ball of earth attached to them for transplanting.

Note: Plant characters such as girth at the collar one year after transplanting and number of nodes two years after transplanting are highly correlated with yield. Removal of plants with poor collar girth and lesser number of nodes one and two years after planting respectively, will help to increase the yield potential of plantations.

Field Planting

Selection of site and layout:

The crop thrives well in humid areas protected well against hot sun and heavy wind. Since the areca palm does not withstand either water logging or drought, the site selected should have proper drainage and adequate source of water for irrigation. Arecanut palm cannot withstand extreme temperature and exposure to direct sun. So the site selected should have protection from southern and western sides. The soil depth and the depth of water table are other two parameters to be considered while selecting the site. The soil should be deep (preferably not less than two meters) and water table should be sufficiently low for better root development. Aligning the rows in north-south direction with a deviation of 35º towards south-west lowers the incidence of sun-scorch.

Spacing:

This depends on the rooting pattern of the crop along with the fertility and depth of the soil. The studies conducted at different places with different spacing have revealed that a spacing of 2.7 m X 2.7 m is optimum for arecanut. This was justified by the root distribution studies also.

Planting:

Dig pits of size 60 x 60 x 60 cm and fill up with rich top soil to a level of 15 cm from the bottom. Plant seedlings at the center of the pit, cover with soil up to collar level and press around.  In well-drained soils and in the fields where proper drainage can be provided, deep planting is preferred. Deeper planting provides a firm anchorage and larger volume of space for root development. In areas where water table is high, shallow planting is preferred. Thus in well-drained soils, planting at a depth of 90 cm is recommended and in heavy soils planting at a depth of 60 cm is recommended.

Season of planting:

In areas where South-West monsoon is severe, planting in the month of September-October is recommended. The planting is to be done during May-June in well drained soils and during August-September in clayey soils

Shading:

The palms are highly susceptible for sun scorching. The seedlings should be given protection against the direct exposure to sun. This may be done by either covering the plants with areca or coconut leaves or by raising crops like banana in between two rows of arecanut. Sun scorching is mostly seen during October – January. During this period even the stems of young palms have to be protected. For this a quick growing shade plant can be planted on Southern and Western sides of the garden.

Cultural Operations:

Keep the garden free of weeds and break up surface crust by light forking or digging after cessation of monsoon during October-November. In slopes, prevent soil erosion by terracing. Sow seeds of green manure-cum-cover crops such as Mimosa invisa, Stylosanthes gracilis and Calapagonium muconoides in April-May with the onset of pre-monsoon rains. Cut and apply them to the palms in September-October.

Nutrient management

Apply green leaf and compost, each at the rate of 12 kg per palm per year from first year of planting onwards, during September-October.

Apply N:P₂O₅:K₂O for adult palms @ 100: 40:140 g / palm / year.

Apply 1/3 dose during first year, 2/3 dose during second year and full dose from third year onwards. Under irrigated conditions, apply fertilizers in two split doses, the first during September-October and the second during February. Under rainfed conditions, apply the second dose during March-April after the receipt of summer rains. Apply manures and fertilizers during September-October in circular basins of 15-20 cm depth and with a radius of 0.75-1.0 m from the palm. Apply the second dose of fertilizers around the base of palm after weeding and mix into soil by light forking. In acidic soils, broadcast lime at the rate of 0.5 kg per palm once in two or three years and incorporate into soil by forking during March-April.

Fertigation:

Application of nutrients through irrigation water is called as fertigation. This procedure can be profitably followed in arecanut. The studies at CPCRI have shown that in the initial stages of areca garden only 75% of the recommended dose of fertilizer is sufficient when the fertilizer was given through drip irrigation. The fertilizer should be split into ten parts and should be applied once in 20 days from November to May.

Organic matter recycling:

On an average, 5.5 to 6.0 tonnes of wastes are available from one ha of areca garden per year. This can be effectively used as organic source of nutrients for areca palms. But direct application of these wastes in the garden will take long time for decomposition and will not meet the nutrient demand of the crop immediately. Hence, these materials can be composted using earthworms effectively and used as organic manure in areca gardens. To prepare vermicompost, areca wastes are chopped into small pieces of 10 cm and heaped. The heap should be mixed with cow dung slurry @ 10 kg / 100 kg of waste and kept for two weeks with sprinkling water daily. Then the chopped material is arranged in beds of one-meter width and convenient length. Cement tanks or trenches can be used for this purpose. A layer of 10-15 cm waste material is alternated with 2 cm layer of cow dung over which earthworms are released at the rate of 1000 numbers per square meter. The wastes are converted into fine granular, odourless vermicompost within 60 days. During this period, the earthworm population is doubled. About 8 kg /palm/year of vermicompost meets the crop nutrient demand in terms of nitrogen. The two species of earthworms Eudrilus eugeniae and Eisenia foetida can be used.

Irrigation and Drainage

Arecanut cannot withstand drought for a long time. Being a perennial crop, once affected by water stress, it may require two-three years to regain the normal vigour and yield. The death of palms due to moisture stress is also not uncommon.

In West Coast of India, where more than 50 per cent of arecanut is cultivated, rainfall is mostly confined to June-November months. Monsoon is followed by a prolonged dry spell normally extending from November to May. Excess evaporation, faster rate of wind speed, greater vapour pressure gradient in the above ground atmosphere and rise in temperature are the regular features of summer in these regions and as a result, the crop is invariably subjected to drought conditions. If the monsoon is delayed, the drought situation further aggravates. Therefore optimizing the irrigation requirements and also economizing the irrigation water assumes major importance in arecanut cultivation. Irrigate the palms during hot and dry periods at regular intervals of 3-5 days depending upon the soil type.

The palms should be irrigated once in four to seven days depending on the soil type and climatic factors. In West Coast, where major areas of arecanut gardens are irrigated, watering the garden once in seven or eight days during November-December, once in six days during January-February and once in three to five days during March-April-May is recommended. In each irrigation, give about 175 litres of water per palm. Where there is shortage of water, follow drip irrigation. Application of organic mulch to the garden helps conservation of soil moisture.

Construct drainage channels (25-30 cm deep from the bottom of pits) between the rows and drain out water during periods of heavy rainfall to prevent waterlogging.

Arecanut based cropping system

Arecanut is cultivated with spacing of 2.7 X 2.7 m provides ample scope for cultivation of various annual, biennial and perennial crops in the inter spaces. The crop chosen should not have any problem of soil exhaustion and pest build-up. At the same time, it should have maximum production potential and give maximum returns per unit input to the farmers. Crops, which love shade or those which can withstand the canopy of arecanut palms and heavy dripping during the monsoon are to be preferred.

Crops like banana, pepper, cocoa, elephant foot yam, citrus, betelvine, pineapple etc. were found suitable for inter/mixed cropping in arecanut. However, it is found that as the age of the garden advances, only few crops can be grown profitably as mixed crop viz., pepper, cocoa, banana, lime and betelvine. The intercrops, apart from giving additional income, create additional employment opportunities.

Crop husbandry for mixed crops in arecanut garden

* Planted at the base of the palms; † Planted at the centre of four palms.

# RP – Rock phosphate; $ MOP – Muriate of potash

Plant Protection

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Pests

Mites

Orange coloured mites can be controlled by spraying the bunches with dimethoate at 0.05 per cent.

Spindle bug (Carvalhoia arecae)

The feeding injury is caused on the lamina and petiole. The affected leaves show dry brown patches.

Spray crowns with carbaryl 50 WP. The spray should reach the leaf axils. Repeat spraying after 30-35 days if pest incidence continues.

Inflorescence caterpillar (Batachedra sp.)

Force open the inflorescence out of the enclosing spathe and spray malathion 50 EC (250 ml in 100 litres of water). Control slugs, which predispose inflorescence to the attack of caterpillar, by using bait of metaldehyde.

Root grub (Leucopholis burmeisteri)

Loosen soil around the base of palms to a depth of 10-15 cm and drench with chlorpyrifos 0.04% suspension twice, one in May just before the onset of southwest monsoon and again in September-October towards the close of the monsoon. Repeat application for 2 or 3 years consecutively to secure a complete eradication of the pest.

Diseases

Koleroga (Mahali or fruit rot) (Phytophthora palmivora)

Koleroga is a major disease of arecanut causing serious losses. Spray Bordeaux mixture 1% on all bunches three times in a year, one just before the onset of southwest monsoon and the rest at 40 days intervals. If monsoon season is prolonged give a third spray. Use rosin soda adhesive to ensure tenacity of the spray deposit on treated substrate. Remove and burn all fallen and infected nuts. Covering the bunches with polythene bags is an effective alternate method of control

Bud rot (Phytophthora palmivora)

Remove and destroy affected spindle and leaves. In early stages of infection, scoop out affected rotten tissues by making longitudinal side splits and apply Bordeaux paste on the exposed healthy tissues or drench crown with 1% Bordeaux mixture.

Basal stem rot (Anabe) (Ganoderma lucidum)

1. Isolate affected palms by digging trenches 60 cm deep and 30 cm wide around, one metre away from the base and drench with calixin (0.08%) or copper oxychloride (0.3%)
2. Remove and destroy all severely affected palms and stumps of dead palms.
3. Drench the soil with 1% Bordeaux mixture before planting healthy seedlings.
4. Discourage growing of collateral hosts of fungus such as Delonix regia and Pongamia glabra in the vicinity of gardens.
5. Apply 2 kg neem cake per palm.
6. Avoid flood irrigation and water flowing from infected palms to healthy palms.

Yellow leaf disease

Maintain the garden properly to keep affected palms in a healthy condition by adopting recommended manurial, cultural, plant protection and other management practices. Improve drainage conditions in the garden.

Disease management

1. Apply the recommended dose of fertilizers.
2. In addition to the above, apply 160 g of rock phosphate per palm in the affected garden.
3. Apply organic manure @ 12 kg each of compost and green leaves per palm per year.
4. Provide irrigation during summer months
5. Avoid water stagnation in the garden by providing drainage facilities.
6. Grow cover crops in the garden.
7. When only a few palms are affected in a garden, remove them to prevent further spread of the disease.
8. Adopt need based plant protection measures against pests and diseases.

Band disease

Improve soil conditions by loosening hard soil strata, if present, by providing good drainage. Adopt adequate control measures against spindle bug, mealy bugs, scales and mites. Where the results of the above treatments are not found satisfactory, apply powdered mixture of copper sulphate and lime in equal quantities @ 225 g/palm twice a year at the base of affected palms. Application of borax @ 25 g/palm has been found to have an ameliorative effect.

Collar rot of seedlings

Improve drainage conditions in nursery beds and gardens. Drench spindle and base of seedlings with 1% Bordeaux mixture in disease affected nursery or garden.

Dieback of inflorescence

Remove affected inflorescence immediately. Spray zineb (4 g in 1 litre of water) or mancozeb (3 g/l) twice, once just after female flowers are set and again 15-28 days later. Aureofungin solution at 100 ppm concentration is also effective in controlling the disease.

Stem bleeding

Palms in the age group of 10-15 years are more prone to this disease. Symptoms appear on the basal portion of the stem as small discoloured depression. Later, these spots coalesce and cracks develop on the stem leading to disintegration of the fibrous tissues inside. With the progress of the disease, a brown exudate oozes out from these cracks. High water table predisposes the palm to this disease.

Improvement of drainage and root feeding of 125 ml tridemorph (1.5%) is suggested as control measure against this disease.

Sun scorch

Protect palms from southwest sun by wrapping stems with areca sheath or white-wash the exposed portion. Provide reinforcement to palms showing stem fissures. Grow tall, quick growing trees on southern and western sides of garden.

Nut splitting

This can be considered as a physiological disorder than a disease. Palms in the age group of 10-25 years are more susceptible. Symptoms are premature yellowing of the nuts when they are half to three-fourth mature. Later splits develop at the tips, which extend longitudinally exposing the kernel. Sometimes kernel also show splitting and malformation. Rarely the kernel inside may exhibit splitting without visual symptoms on the husk, resulting in nut fall. Hyper nutrition or sudden flush of water after a period of drought or insufficient moisture in the soil is the probable cause (s) of the disease.

Improvement of drainage in ill drained gardens and spraying of borax @ 2 g/litre of water are found effective in reducing the disease incidence.

Harvesting & Processing

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Arecanut has been widely used in South and South-East Asia and the Pacific Ocean Islands. While its primary use has been as a masticator, it is also finding use among the local population in native systems of human and veterinary medicine, in certain religious and social functions. Other parts of the arecanut palm like sheath, stem, leaf, etc. are used in farms and households for manuring, packaging, construction etc.

Harvesting of the arecanut is done by skilled climbers who cover about 50 -100 palms in a day. Mechanical arecanut palm climbing device is available for easy climbing the palm by any unskilled persons. The stage of harvesting depends on the type of product to be prepared. There are two main types viz., kalipak, prepared out of immature green nuts, and chali prepared from ripe nuts. In each case, the maturity at which the fruit is harvested and the season of harvest affects the quality of the processed nut considerably.

Preservation of arecanut with husk

Several age-old and crude methods are followed for preserving arecanut to keep the moist chewing feel. Fresh ripe arecanut is used for chewing in Assam and Kerala. In Kerala the fresh ripe fruits are stored in water and are known as ‘neetadaka’. The nut contains mainly polyphenols, polysaccharides, fibre and fat. The husk contains easily fermentable substances such as sugars and pectins. These are easily attacked by bacteria when stored in water. The husk is loosened and the bright orange color is lost. Because of fermentation foul smell is produced which penetrates into the edible nut. In Assam fresh ripe arecanut is stored in pits. The husk gets attacked by fungus and the fat and polysaccharides from the core is eaten away by bacteria. The nut is thus rendered unsuitable for consumption.

To avoid the problems occurred during the preservation of fresh ripe arecanut in garden fresh condition, a method of preserving fresh ripe arecanut by steeping in mixed preservative solution has been developed. It consists of washing freshly harvested areca fruits in chlorinated water to remove the adhering dirt. The fruits are then blanched in boiling calcium chloride (0.2 %) solution. This treatment reduces microbial load, destroys the enzymes and preserves the firmness of the husk. The fruits are then kept immersed in a solution containing 0.1 % sodium benzoate and 0.2 % potassium matabisulphite acidified to a pH of 3.5 to 4.0 using hydrochloric acid. The fruits can be preserved in fresh ripe condition for 10-12 months. Fresh bright colour and firmness of the skin are maintained. Stored fruits will be free from foul smell without any significant changes in the constituents.

Drying of ripe nuts:

Fresh ripe areca fruits are dried in the sun by spreading in single layers for 35-40 days. The fruits are turned over at regular intervals to ensure uniform drying. To facilitate uniform drying, some times the outer skin is peeled off. Later on they are dehusked and sent to market. Whole dry nuts are known as ‘Chali’ or ‘Kottapak’. The well known grades of ‘chali’ in descending order of size are ‘moti’, ‘Srivardhan’, Jamnagar’ and ‘Jini’. Other characteristics which are valued are uniformity in size, absence of immature nuts, surface cracking, husk sticking, fungus and insect attack and good cutting feel, inside structure and taste.

Lack of attention during drying, unexpected rains and unsuitable wet drying yards contribute to onset of fungal infection and result in a poor quality final product. In Kerala and Assam harvesting season coincides with the monsoon and sun drying is difficult. The main areas producing ‘chali’ nuts are Karnataka, Kerala and Assam. Bangladesh, Malaysia and Sri Lanka also produce ‘chali’ nuts.

To facilitate drying, areca fruits are cut longitudinally into two halves and then dried in the sun. Later they are scooped out and sent to market. This half-cut form is known as ‘parcha’. It is produced mainly in Kerala and Karnataka. In Karnataka its production is concentrated in South Kanara, Sirsi and Kumta area. In Kerala its production is confined to Kasaragod, Nedumangad and Kottayam areas. Small quantities of this type are produced in Assam, Maharashtra and West Bengal. In West Bengal they are processed in parts of Cooch-Bihar and Jalpaiguri districts.

A mechanical through-flow drier is available for making ‘chali’ and ‘pacha’. Drying can be completed in about 60-70 hrs spread over 7-8 days at progressively increasing temperatures between 45-700 C. The drying schedule consists of successive 8 hr. drying period followed by 16 hr. equilibration outside the drier. The parts of the drier are a drying chamber with four perforated trays, a heat exchanger, fuel furnace and a centrifugal blower. ‘Kalipak’ can be conveniently dried using this drier. Small holders’ multipurpose dryer, using agricultural waste as fuel developed by CPCRI can be used for drying arecanut. About 150 kg of arecanut can be dried in this dryer in 100 hrs (10 days).

Storage of nuts:

Lack of proper drying yards, improper spreading and turning of nuts and exposure to unexpected rains during the drying period lead to microbial infection of the husk as well as kernel. Elimination of soil contact by the harvested nuts is beneficial in reducing nut infection since it is the prime source of infection. Harvested nuts treated with copper oxychloride showed less infection. Steeping the nuts in Bordeaux mixture followed by drying on cement floor reduced the percentage of infection significantly. Polythene lined gunny bags can be used with advantage over plain gunny bags for storing nuts. Storage of arecanut in air tight bins also minimizes the fungal infection.

Insect damages by feeding on the inner central core and due to this, holes appear on the surface of the nuts. The insect damage is maximum during the rainy months when the humidity is high and minimum during winter and summer months. Arecanut beetle (Cocotrypes carpophagus Horn) is the most important storage pest of arecanut. The damage is mainly caused by adult beetles, which bore into the nuts and feed on the inner contents. The infested nuts show holes of 0.6-1.0 mm diameter. Both adults and grubs of coffee bean weevil (Araecerus fasciculatus D.) have been reported to damage stored arecanut. Infested nuts have holes 1.5-2.5 mm in diameter. Unhusked nuts with intact perianth are not infested by this insect even after one year of storage. Cigarette beetle (Lasioderma sp.) is a widely distributed storage pest infesting stored arecanuts throughout the year. Both the adult and grubs damage the nuts and make them as powder. The caterpillars of Rice moth (Corcyra cephalonica) construct galleries of silk and frass over stored nuts, remain within and feed on them.

Dehusking

A simple dehusking devise has been standardized by CPCRI., Kasargod. The out turn with this devise is 60 kg of husked nuts in the case of dry nuts and 30 kg in the case of green nuts. The cost of the devise is about Rs. 250

Kalipak

Areca fruits of 6-7 months maturity are used for making this important class of processed arecanut. The main processing centers are Karnataka and Kerala. The outer skin of the husk will be green in color and the immature nut will be soft. The processing consists of dehusking, cutting the soft nut into pieces, boiling the cut pieces with water or a thin extract from a previous boiling, ‘Kali’ coating and drying. Depending upon the number of cuts, different types representing pieces of various sizes and shapes are recognized. ‘Api’ or ‘unde’ is the type which is processed without any cutting. ‘Batlu’ or Ottavettu’ is cut transversely into two halves. ‘Choor’ is produced after several longitudinal cuttings. It is further divided into sub-groups namely ‘mukkachoor’, edachoor’, ‘pettichoor’ etc, in the descending order of thickness. Cutting the nuts both transversely and longitudinally 3 to 4 times produces ‘Podi’. ‘Erazel’ and ‘Chalakudi’ are thin slices produced by slicing the nuts transversely or longitudinally.

During the boiling operation, the same water is used for boiling 2 to 3 batches of arecanuts. The extract so obtained is concentrated to get ‘Kali’. After boiling, the pieces are coated with ‘Kali’, which imparts a good glossy appearance. In interior Karnataka the boiling and ‘kali’ coating operations are combined into single operation. The cut nuts are boiled in a thicker extract called ‘Chogaru’. ‘Lylon’ is an unboiled variety made from green arecanuts. The nuts are cut into 5 or 6 discs transversely and dried without kali coating. The nuts will be slightly more mature than those used for ‘kalipak’. Tamil Nadu and Andhra Pradesh are important consuming areas. The grades in increasing maturity and therefore decreasing grade are ‘Chittanum’. ‘Virivu’ and ‘Kora’. ‘Nayampak’ is also unboiled type and is made from immature arecanuts after cutting once transversely and drying.

Both sun drying and oven drying are practiced by ‘Kalipak’ processors. A well dried product with a dark brown colour is preferred. Other desirable qualities in ‘Kalipak’ are crisp chewing feel, glossy appearance, a well toned astringency and absence of over mature nuts.

Sagopalm nut is used for adulterating ‘Kalipak’ samples. The cut pieces have a similar cut surface and are coated with ‘kali. The chemical analysis revealed that sagopalm nuts have lower polyphenol and fat contents but have higher polysaccharides and fibre contents. Other adulterants used after ‘kali’ coating are sweet potato and tapioca and they are comparatively easier to identify.

Scented Supari:

There are many varieties of scented suparis. The processing consists of breaking the dried nuts into bits, blending with flavour mixture and packaging. Roasting of bits in oil or ghee is also practiced. Batlu adike is mainly used for making scented supari. In North India scented supari is made from ‘Chali’ nuts in addition to those made from ‘Kalipaks’. The chali supari is more popular. About 75 per cent of the marketed produce is consumed after processing either as kalipak or chali. The flavoring varies depending on the region and it is a closely guarded secret. Rose essence is used in most of the cases. Coconut grating which were used in earlier days are now avoided as they get fungal infection.

Taste characteristics of nut:

Astringency is the characteristic taste of arecanuts. Polyphenols, which are present abundantly in it, are responsible for this. Astringency is felt as a contracting and drying sensation. The astringent characteristics in arecanut decreases with maturity.

Colour development on chewing

The chewing of arecanut with betel leaf and slaked lime is very popular in India and neighboring countries. In addition to the stimulation and pleasant taste, chewing results in bright red colour of the mouth. Catechin turns brilliant red immediately after addition of alkali (pH 10) which gradually turns reddish brown on keeping for more than two hours. Similarly, the leucoanthocyanidins, which become dark red initially, turn dull brown in about two hours and pale brown on keeping over-night. The polymeric proanthocyanidins, which contain mostly leucocyanidin units also behave similarly. The colour change of all the compounds at pH 8 is basically similar though rate of change is different.

Alternative Uses & Waste Utilisation

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Tannins:Tannins are obtained as a by-product from the process of preparing immature betel nuts for masticatory purposes. It was found that tannic acid from the nut, when mixed with ferrous sulphate in warm distilled water gave black writing ink of acceptable quality. He used immature fallen nuts for this purpose. Other uses of tannin are as adhesive in plywood industries and as a textile dye.

Fats:The nuts contain 8-12 per cent fat. Fat from arecanut, can be extracted by solvent extraction using hexane. Areca fat has comparable characteristics with hydrogenated coconut oil. Areca fat can be made edible by refining with an alkali. The fat could be softened by fractional crystallization using hexane (25ºC) and randomization using sodium methoxide, which gave products desirable for use as confectionery fat. Simple blending of areca fat with butter fat and cocoa fat at 3:1 ratio followed by interesterification of areca fat and cocoa fat at 1:1 ratio gave good products acceptable in confectioneries.

Arecanut husk:

It is the outer cover of areca fruit. It constitutes 60-80 per cent of the total volume and weight of the fruits (fresh weight basis). It is now being largely wasted except for being used as an inferior fuel and mulch. Several processes have been developed for utilization of areca husk for making hard boards, plastic and brown wrapping paper. Areca husk is used as a substrate for mushroom cultivation. Arecanut husk fibre is generally longer than woolenised jute, goat hair or coir fibre. About 50 per cent of arecanut husk fibre is finer than other fibres and the remaining 50 per cent of fibre is coarser than those fibres. The tenacity value of arecanut husk fibre is comparable with that of goat hair and woollenised jute. Wet weight of arecanut husk fibre is comparable with that of other fibres. The weight and thickness of all fibre reinforced plastic sheets are comparable. The proportion of fibre in the fibre reinforced plastic sheets varied between 7.6 and 9.9 per cent. The proportion of arecanut husk fibre is higher (9.12 per cent) in comparison with that of glass fibre (7.9 per cent), though the thickness and water swelling ie, increase in weight of the sheets by immersion in water for 20 days, values are same.

Areca leaf sheath:

Leaf sheath is yet another raw material obtained from the arecanut palm. In a year palm sheds 5-6 leaves. A process has been developed for making plyboards from areca leaf sheath. These boards can be used for making suitcases, fileboards, and tea chests. Leaf sheath cup making machine is available in the market for making arecanut leaf sheath cups of different sizes and shape.

Arecanut leaf sheath was found suitable for making plyboards. Two plies of processed arecanut leaf sheaths in combination with an ordinary wood veneer as core glued with urea formaldehyde resin are used for making the plyboards. Leaf sheaths obtained from the farm are highly heterogenous having variations in structure, shape and thickness. The rear end is thicker and the two edges are thinner. The thickness at the center ranges from 3.0 – 8.5 mm (average 5.0 mm). A comparatively homogenous piece of fairly uniform thickness and size 50-65 x 20-25 cm can be obtained if a piece of about 10 cm length from either sides along the grain direction, 5 cm from the distal and 10-15 cm from the end across the grain direction are trimmed out from the sheath. Further, to get a flat sheath of uniform thickness and to remove the buck lings of folds, the sheath is flattened under pressure and heat. For this, the sheaths are soaked in water to about 75 per cent moisture and then pressed for 30 min in a hot Plate press at 4 kg/cm2 pressure and 110ºC temperature. This process gives flat sheaths of 1.0-1.5 mm thickness with about 12 per cent moisture. To prevent fungal growth on the sheath surface, it can be soaked in 1 per cent copper sulphate solution for 24 hr before pressing. The pressed sheaths are then air dried for one hour or longer. The arecanut leaf sheath plyboards made with two veneers of areca sheaths as the faces and one veneer of even an ordinary wood species like Mango as core ply and bonded with Urea formaldehyde resin make commercially acceptable boards with average dry and wet glue shear strengths of 50 kg and 12 kg respectively.

Arecanut stem and leaf:

Arecanut stem forms a useful building material in the villages and is widely used in arecanut growing area for a variety of construction purposes. The leaves are good source of organic manure. Their approximate composition is N2 (0.94 per cent); P2O5 (0.096 per cent) and K20 (1.00 per cent).

Utilisation of waste of arecanut plantation for mushroom production

In India, the cultivation of mushrooms is limited to three species viz., white button mushroom, paddy straw mushroom and oyster mushroom. Oyster mushrooms are the ideal ones for the arecanut sector due to its ability to utilize lignin rich arecanut wastes and the climatic conditions prevailing in plantations are also ideal for its growth. Oyster mushrooms, known as wood fungi, are endowed with ligninolytic and cellulolytic properties to utilize a wide range of agricultural residues as substrates for growth and fruit body production. Paddy straw is the most widely used substrate for its cultivation. But its increasing cost and decreasing availability are factors, which prompted research workers to look for alternate substrates for oyster mushroom cultivation. Conditions have been standardized for cultivation of oyster mushrooms using arecanut leaf sheath and bunch waste. The steps in oyster mushrooms cultivation include development of spawn, substrate preparation, spawning, incubation for spawn running and opening and maintenance of beds for cropping.

Spawn, the vegetative seed of the fungus, can be obtained either from research institutions or can be prepared with adequate training. An efficient and stable strain of Pleurotus isolated from sporocarps should be used for spawn preparation using grains such as wheat, sorghum, maize, jowar or paddy straw as substrates. Pasteurization of substrates is necessary to avoid contamination and to obtain higher yield. Steam sterilization, hot water treatment and chemical sterilization are the effective methods. Steam sterilization at 1.02 kg/cm2 pressure in an autoclave for one hour is an efficient method of sterilization. Hot water dip of the substrate at 80°C for 60-120 minutes is another method, which can be easily adopted. Chemical sterilization method involves treatment with formalin and bavistin in substrate soaking water for 18 hours. Arecanut bunch waste and leafstalk are pasteurized by soaking in a solution of 500 ppm formalin + 25 ppm bavistin.

Polyethylene bag method is the commonly followed method of cultivation. Polyethylene bags (150-200 gauge) of 66 x 45 cm size are punched to facilitate cross ventilation. Spawning is done by multilayered technique using 3 per cent spawn. For spawn running and cropping, the filled up bags are incubated in cool dark place. In 15 to 20 days white thread like mycelium covers the entire substrate and the whole mass turns into a solid cylindrical structure. At this stage the polyethylene bags are ripped open and incubated for cropping by hanging or by stacking on the shelves of mushroom house with watering daily twice after two days of opening of beds.

Low cost mushroom sheds can be built with coconut/areca stem and plaited coconut leaves inside arecanut plantations. Multilayer rack can be prepared with coconut/ areca stem inside the shed to keep the spawned substrate for spawn running and cropping. Ventilators with insect proof nets are to be provided on all sides of the shed. Mushroom production is 69 per cent and 49.8 per cent in a cropping period of 47 to 52 days in arecanut bunch waste and leaf sheath, respectively.