Abstract:
Abstract. The lychee (Litchi chinensis Sonn.) fruits (a species of the Sapindaceae family) is of
Chinese origin and is perfectly adapted to Egyptian climatic conditions. This study included the
evaluation of fresh lychee flesh, seeds and pericarps, also fresh lychee flesh treated with sugar solution
(sucrose 20 °Brix) in refrigerator (4±1°C) during storage for 12 months, also fresh lychee flesh treated
with sucrose 40 °Brix (as an osmotic agent) was dehydrated in air oven drier (60°C) and oven drier
under vacuum (50°C) at ambient temperature (25±2°C) during storage for 12 months.
The obtained results showed that, fresh flesh lychee was higher in weight percentage (73.22%) than
lychee seeds and pericarps (17.58 and 9.20%, respectively) of the total weight of fruits. There were
also, no significant variance in crude oil content between fresh flesh lychee and flesh lychee in sugar
solution (0.68 and 0.63%), respectively. While, lychee seeds were possessing high content of crude oil
(3.72%) followed by lychee flesh dried under vacuum and oven dry (3.62 and 3.53%, respectively)
after dipping in sugar agent, then crude oil in pericarps were the lowest content of crude oil (2.98%).
While, protein and crude fiber contents were higher in pericarps (9.25 and 28.34%) respectively, than
seeds (8.73 and 21.42%), also the content of protein and crude fiber were nearly in dried lychee under
two treatments of dehydration (6.94, 7.02 and 6.84 and 6.88%), respectively. Furthermore, dried flesh
lychee in oven or under vacuum gave high calories (374.45 and 375.22 kcal./100g), respectively,
followed by lychee seeds then pericarps (317.78 and 287.26 kcal./100g).
Results, also indicated that, lychee seeds were having the highest contents of w 6 andw 9 (2226.65
and 1144.56 mg/100g, on dry weight basis), respectively. While, fresh lychee flesh treated with
osmotic solution was decrease in w 9, 6 and 3 contents (79.25, 95.87 and 29.61 mg/100g, on fresh
weight basis, respectively) compared to fresh lychee flesh without any treatment (98.94, 117.16 and
39.92 mg/100g, on fresh weight basis), respectively. Also, lychee flesh dried under vacuum was higher
contents in w6 and w3 (924.84 and 393.48 mg/100g, on dry weight basis, respectively) than dried
by oven dryer, while the same treatment had highest content in w 3 than other treatment and other
parts of lychee fruit (seeds and pericarps).
The results also indicated that, lychee seeds had highest content of total polyphenols, total
flavonoids, total carotenoids, L-ascorbic acid and anthocyanins followed by lychee pericarps then
fresh lychee flesh except vitamin C, fresh lychee flesh had higher contents then pericarps. These
results reflected to antioxidant activity, whereas, seeds had higher antioxidant activity (87.00%) than
fresh lychee flesh and pericarps (81.00 and 78.00%), respectively.
The results showed that, the total soluble solids, pH and acidity were ranged from 16.50, 4.42 and
0.38 to 15.95, 4.36 and 0.45, respectively in fresh osmotic lychee flesh during refrigeration storage.
The contents of total polyphenols, total flavonoids and total carotenoids had not significant changes
during storage for 12 months. While, vitamin C content was decrease 1.46% in after storage 12
months, but this decrement is not statistical significance.
The results total polyphenols, total flavonoids, total carotenoids and anthocyanins contents in
oven dried (60°C) on osmotic lychee flesh during storage for 12 months at room temperature (25±2°C)
had no significantly decrease changes till 8 months. Also, vitamin C contents in osmotic lychee flesh
affected by oven dry treatment till 6 months, in addition, vitamin C contents was decreased
significant till the end of experiment (7.10%). While, total polyphenols, carotenoids, anthocyanins
contents had no significant decrease till 10 months in dried osmotic lychee flesh at 50°C under
vacuum (Osmovac) treatment. But, it’s observed the content of vitamin C was gradually significant
decreased (from 360.38 to 350.00 mg/100g on dry weight), the percentage of decrement was 2.88% at
the end of storage in osmovac treatment.
The results confirmed that, the fresh lychee flesh treated with osmotic agent and dried lychee flesh
at 50°C under vacuum (Osmovac) were the most suitable treatments for storing and keeping the
antioxidant contents, especially vitamin C. Also, osmovac treatments can retain their high quality of
lychee flesh for 1 year at room temperature compared to osmotic oven dried at 60°C flesh lychee
fruits (8 months). While, seeds and pericarps were rich in bioactive components as omega fatty acids,
anthocyanins and others, may use in food and pharmaceutical products for their value for sustainable
development in future studies.
|