Generally, blanching is carried out by the application
of a wet medium such as steam or hot water in order
to provide uniform heating and a high-heat transfer
rate. Both in domestic and industrial processing, several
blanching methods may be employed such as conventional
water blanching, microwave, or steam blanching;
the regime being dictated by the nature of the raw
material and the desired properties of the final product.
Traditionally, blanching is carried out either at a low temperature
(55–75°C) for long-time, typically referred to as
LTLT or high-temperature short-time (80–100°C) for less
than 10 min, referred to as HTST depending upon the
type of vegetable (Abu-Ghannam and Crowley, 2006).
Conventional water blanching usually imparts more
uniform processing. However, prolonged water blanching
results in considerable losses in phytochemicals and
antioxidant properties (Jaiswal et al., 2012c).
Microwave heating is three- to five-times