Dried lychee products are about 80% of total processed lychee
in China which are mainly processed by hot air and vacuum drying methods. All dried lychee products purchased from
market were dried with pericarp due to its high sugar content
and it could be divided into two groups: semi-dried lychee
(30%, w.b.) and dried lychee (15–20%, w.b.). These dried lychee
products are soft and have very sweet taste which make them
unattractive to some consumers.
High content of reducing sugars in lychee pulp results in
browning during drying process. So, mixing lychee with other
food materials is done in order to reduce their sugar content.
Food materials containing starch are suitable for mixing with
lychee because these materials tend to reshape due to the viscosity.
In this research, purple potato was chosen to be mixed
with lychee because of its unique characteristics which are as
follows: low sugar content, weak odor and taste, high starch
composition and lots of phenolic compounds that are healthy
to human. Amylopectin proportion in total starch of purple
sweet potato and its swelling potential of starch are low. So
re-structured purple sweet potatoes with adding water rather
than slices could be used to produce the puffing snacks (Liu
et al., 2012).