الفهرس 
REVIEW OF LITERATURE
Plant material and experimental designOnly 14 pages are availabe for public view
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Abstract
This study was conducted during two successful seasons of 2013 and 2014 to
improve fruit quality of Early sweet grapes (Vitis vinifera L.,) as affected by Arabic
gum, potassium silicate and modified atmosphere packing (MAP).
Early sweet grapes were harvest from a private vineyard in Cairo Alexandria desert
read, Giza Governorate, Egypt. The grapevines cultivar Early sweet were five years
old, grown in sandy soil under drip irrigation system and planted at 1.5 X 3.0 meter.
Cultural practices were done according to general field recommendation including
fertilization, pruning as well as pest diseases control.
Clusters were picked in early morning at the ripening stage in middle of June during
both seasons. Ripening stage (TSS ≈ 14 – 15 %) and acidity (0.4 – 0.5 %), complete
yellow color of berries skin and clusters hand harvest. Healthy clusters free from
physiological and pathological were chosen. Moreover, uniformity clusters size, color
and firmness were observed. Clusters were harvested in carton bags, and then
immediately transported from the orchard to the postharvest laboratory at the
Department of Horticulture, Ain Shames University and treated on the same day.
Clusters were washed with tap water containing color x 1% (0.05% sodium
hypochlorite) and air dried, then divided into groups and treated with following
treatments.
The used treatments were
1. Clusters treated with 1.5 % potassium silicate (PS) were wrapped using heat
shrinkable films (SH) (PS + SH).
2. Clusters treated with 1.5 % potassium silicate (PS) were packaged in modified
atmosphere packaging (MAP) by using 40 mu (PS + MAP 40 mu).
3. Clusters treated with 1.5 % potassium silicate (PS) were packaged in modified
atmosphere packaging (MAP) by using 80 mu (PS + MAP 80 mu).
4. Clusters treated with Gum Arabic (GA) (25% w/v) were wrapped using heat
shrinkable film (SH) (GA + SH).
5. Clusters treated with Gum Arabic (GA) (25% w/v) were packaged in modified
atmosphere packaging (MAP) by using 40 mu (GA + MAP 40 mu)
6. Clusters treated with Gum Arabic (GA) (25% w/v) were packaged in modified
atmosphere packaging (MAP) by using 80 mu (GA + MAP 80 mu)
7. Control clusters: untreated clusters.Treated clusters were rapidly and carefully were placed in three perforated carton
boxes (30×40×20 cm) for each treatment. Each box contained 2 kg clusters was
replicated three times and the experiment was repeated twice (2013 and 2014
seasons). Boxes of all treatments were subjected randomly to one of the pervious
treatments and stored at
1. Refrigerator at O ± 1 Co with 90 ± 5% RH for 28 days.
2. Refrigerator at 7 ± 1 Co with 90 ± 5% RH for 28 days
1. Effect of different treatments on physical properties of Early sweet grape
under cold storage
1.1 Weight loss percentage
It is clear that weight loss increased gradually during the storage period of Early
sweet grape stored at 0 and 7oC. The highest weight loss for clusters dipped in
potassium silicate (PS) or in Gum Arabic (GA) plus wrapped by perforated
polyethylene (PPE) bags 80 mu with no significant between them. On the other
hand the least values of weight loss were for the clusters dipped in potassium
silicate or dipped in Gum Arabic plus wrapped by shrink film (SH). At the end of
storage period the control gave the highest significant percentage of weight loss.
1.2 Berry Decay Percentage
Decay percentage was increased considerably with prolonged storage period in all
treatments in both storage degrees for two seasons. All treatments significantly
reduced the decay of Early sweet grape than the control treatment during both
season and both storage temperature. The lowest values for decay percentage
were obtained as a result of dipping clusters in Gum Arabic (GA) or potassium
silicate (PS) plus warped by heat shrink (SH).
1.3 Berry Shatter Percentage
Berry shatter percentage was gradually increased by storage period advanced for
two storage degrees in both seasons. Thus, clusters dipped in Gum Arabic or
potassium silicate and warped by heat shrink significantly reduced berry shatter %
than the control with no significant deference between them at the end of storage
period. Potassium silicate with heat shrink treatment (PS + SH) had the lowest significant percentage of shatter percentage at both degree storage during both
seasons at the end storage period. Dipped in potassium silicate or Gum Arabic and
wrapped by PPE 80 mu, untreated clusters gave the highest percentages of
shattering with no significant differences among them.
1.4 Discarded Berries Percentage
Discarded berries percentage was gradually increased by storage period advanced.
Dipping Early sweet grape in potassium silicate (PS) and wrapped with shrink
film (SH) significantly reduced the percentage of discarded berries percentage in
two seasons at both degree storage than the other treatments or the control.
Meanwhile, clusters were dipped in Gum Arabic plus covered by shrink film (GA
+ SH) was given near value to potassium silicate (PS).
1.5 Bunch Freshness
The color changing of bunches were acceptable and the browning of stem, rachis
increased during storage. However, it was maximum in case of control fruits
compared to all another treatments. Dipping in Gum Arabic or potassium silicate
and warped with heat shrink and control was highly significant. This indicating
that antifungal action of gum Arabic and potassium silicate and another material
tested in warp.
1.6 Berry Firmness
The average firmness decreased as the storage period increased reaching its lowest
values at the end of storage in both storage degrees during two seasons. The
highest significant value of berry firmness obtained from dipping in potassium
silicate or Gum Arabic with covering by polyolefin heat shrink flowed by dipped
in potassium silicate with covered by polyethylene bags 40 mu in descending
order as compared with the control treatment and Gum Arabic with polyethylene
bags 80 mu in both seasons which gave the lowest significant values.
1.7 Berry adherence strength
The higher berry adherence found in grapes dipping in Gum Arabic plus wrapped
by shrink film (GA + SH) so also potassium silicate with shrink film (PS + SH).
Berry adherence strength was gradually reduced by storage period advanced till 28 days. Potassium silicate with shrink film (PS+SH) reduced berry adherence
strength from harvest day to end storage in both degrees for two seasons. The
highest level suggested for control nearly using Gum Arabic with perforated
polyethylene 80 mu (GA + PPE 80 mu) with no significant value.
2. Effect of different treatments on chemical properties of Early sweet grape on
cold storage
2.1 Total Soluble Solids PERCINTAGE (T.S.S%)
Total soluble solids content of stored fruits gradually increased with extend of
storage period during both seasons under study. On the end of storage days, the
untreated clusters and treated clusters with potassium silicate and gum Arabic plus
profited polyethylene 40 and 80 mu give the lowest values of T.S.S without
significant different between them. On the contrary potassium silicate with heat
shrink (PS + SH) to reach the highest value to Gum Arabic with heat shrink (GA +
SH) as compared with the control treatment.
2.2 Total Acidity Percentage
After 7 days storage no significant differences were noticed between different
treatments and both storage temperature. The significant differences appeared
after 14 days, Gum Arabic treatment plus heat shrink achieved the least percentage
of acidity during both season under study respectively.
2.3 Total Soluble Solids / Acid ratio:
Maximum value for dipped on gum Arabic with heat shrink (GA + SH) while the
lowest value were suggested to dipped on Gum Arabic and covered with profited
polyethylene 80 mu (GA + PPE 80 mu) at 0Co in first season while storage under
7Co maturity index were in the same trend with change in values for each
treatment.
2.4 Respiration Rate
Noticeable decrease in values of rates of respiration at end of cold storage period
compared with the initial respiration rate values at harvest day in all postharvest
treatments during the two seasons of investigation. Dipping in Gum Arabic (GA)or potassium silicate (PS) and wrapped by shrink film (SH) tend to have the
effective role in reducing the rate of respiration of grape clusters.
3. Effect of different treatments on Early sweet grape at market temperature
for 7 days after cold storage
3.1 Effect of different treatments of physical properties on Early sweet grape at
market temperature for 7 days after cold storage
The best treatment for dipped in potassium silicate (PS) or Gum Arabic (GA) and
wrapped by shrink film (SH) (PS + SH) or (GA+ SH) tend to have a good quality
and appearance with no significant difference between them, they have a
significant decreased weight loss, decay, shatter and total loss berries percentages
compared with all treatments so also berry firmness and berry adherence which
suggested highest significant value compared with all treatments. On the other
hand untreated treatment (control) and dipped in Gum Arabic and covered by
profited polyethylene 80 mu (GA + PPE 80 mu) were the worst results with no
significant different between them as compared with all treatments. This is true
for the two seasons of the study
3.2 Effect of different treatments of chemical properties on Early sweet grapes at
market temperature for 7 days after cold storage
Total soluble solids (T.S.S), acidity percentages, T.S.S / acid ratio and
respiration rate were affected with long storage and marketing duration. T.S.S% and
T.S.S / acid ratio values were converging to increase after week of marketing while
acidity values were decreased for dipping in potassium silicate (PS) or Gum Arabic
(GA) and wrapped by shrink film (SH) (PS + SH) or (GA + SH). While worst
treatment for dipped in Gum Arabic and covering by profited polyethylene 80 mu it
was nearly with value of control treatment with no significant between them so it
assisted on TSS, acidity and TSS / acid ratio. When subjected respiration rate (gm
CO2/Kg/h) we find that no differences between all treatments. This is true for the two
seasons of the study.