In Asian cooking, acid flavors are achieved
by adding fruit juice, pulp or whole fruits with piquant flavors. Some
acid fruits, example tamarind, are widely available and well known. Others
are only known in the area of origin.
Some common acid fruits are like belimbing
or billing (Averrhoa bilimbi) which looks like a miniature cucumber
with thin, pale green skin and belongs to the same family as star fruit;
gamboge (Garcinia cambogia) which starts out as a brilliant
orange-colored segmented fruit but is dried for storing, turning black in
the process; and asam gelugor (G.atroviridis), a sour fruit which
is sliced, dried and used instead of tamarind in certain Malay dishes.
What leads to confusion is the free-wheeling
labeling of some producers, who refer to gamboge as 'fish tamarind' and
gelugor as 'tamarind slices', though they are not even from the same
botanical family as tamarind. The fact that they provide acidity is reason
enough - for them, at any rate - to justify the mislabeling.
In India, unripe mangoes are dried and
ground into a powder called amchur which is useful when a piquant flavor
is required without the liquid element of lime juice or tamarind. Dried
pomegranate seeds, anardhana, are used in Indian cooking and added to
certain dishes for a sour flavor.
Limes of many different types are used
throughout Asia, with some kinds being flavored in certain countries. In
the Philippines, kalamansi (small round citrus fruits also called musk
lime) are indispensable. Malaysian cooks use limau nipis (a large lime)
and limau kesturi (another name for kalamansi). In Indonesia, Malaysia and
Sri Lanka, tamarind and fresh lime juice are as essential as salt. In
Thailand, cooks cannot do without the highly perfumed rind and leaves of
makrut (kaffir lime), a deep green fruit with knobby skin.