Hainan province produces 99% of areca nut produced in China and rest is produced in Yunnan, Guangdong, Guangxi, Fujian provinces. A systematic monoculture plantation of areca nut is found in Hainan province. Green immature areca nuts of size 3-5 cm long (perhaps 4-5 months’ maturity) are harvested, and individual nuts are separated from the bunch. These fresh whole areca nuts without removing the husk are processed into refined betel nuts, referred to as “Binglang”, through complex process involving boiling, flavour addition, brine addition and drying. Binglang is a refined, processed areca nut devoid of the kernel (seed). Over 95% of the harvested nuts are processed into dried betel nuts in Hainan province and transported to Hunan Province for the production of "Binglang".
Blanching is
the first step in the traditional processing of fresh betel nuts, which
involves cooking in boiling water for 30–50 min followed by the drying and
roasting of the nuts by using smoke generated by burning moist rubber wood.
Generally, after these processes, the moisture content of the betel nut will
reach about 15%. The smoked betel nuts gradually develop a dark skin due to the
accumulation of smoke particles on the surfaces and hence they are commonly
named smoked or black nut and exhibit a distinctive smoky flavor. Such dried
nuts are transported to Hunan province for the production of "Binglang".
Typically, the smoked nuts are boiled under atmospheric pressure for
approximately 20 min. Food-grade sodium hydroxide, sodium bicarbonate, sodium
carbonate or calcium hydroxide, are added while cooking. After cooking, the
betel nuts are usually treated with an enzyme to soften the fibers and
eliminate astringency. Then, betel nuts are immersed in a solution containing
sugar, sodium cyclamate, licorice extract, vanillin and edible flavors and
steeped for couple of days at room temperature. The moisture content of betel
nuts after this step typically reaches 45%. Therefore, the nuts are roasted to
reduce the water content by hot-air baking techniques and fix the sweeteners. The
dried sweet nuts are soaked in proprietary solution containing various flavors
and fragrances and this process usually takes 3-24 hours. To improve the visual
quality of the flavored sweet nuts, the ovoid betel nuts are flattened by
using hydraulic equipment, which alters their shape to become flat, loosens the
fibers and creates specific patterns. these flat nuts are given a surface
coating by spraying a mixture of gelatin, gum arabic, carrageenan and modified
starch, in addition to sweeteners, preservatives, fragrances and flavors. After
giving the surface coating, the betel nuts are transported to the high-clean
area and the betel nut is cut into two pieces and then the kernel is picked
out. that space is filled with a suitable amount of special brine. This filling
is considered as the “soul” of the Binglang
(refined betel nut) as it has a special effect on its flavor and texture. The
brine formula and preparation process developed by different manufacturers are
highly confidential. Typically, the brine solution consists of maltose
(30~80%), food grade calcium hydroxide (10~40%), white sugar, additives
(0.5~5.0%), water and natural flavorings. After brine dipping, the betel nuts
are dried naturally to stabilize the moisture at about 22-24 %. After the drying process, the refined betel
nuts are packaged for sale.
References:
1. Zhu et al.,
(2023). Research Progress on Processing Technology of Refined Betel Nut in
China: A Review, Processes, Vol. 11, 3199.
2. Chen et al., (2007). Study on the
processing technique of edible areca. Food Sci. Technol. Vol. 32, pp. 57–59.