Soy Protein Isolate (90% protein) u

Soy Protein Isolate (90% protein) used in the
experiment was purchased commercially. Glycerol
(LR grade) used as plasticizer and Carboxymethyl
Cellulose, Oleic Acid, Sodium Benzoate and
Ascorbic Acid were purchased from local chemical
supplier. Sodium Hydroxide (LR grade) used for pH
adjustment was also purchased from S.D. Fine
Chemicals Pvt. Ltd. The tomato sample used in study
were purchased from local market and graded as per
equal maturity level.
2.1 Coating Solution Preparation and Application
Soy protein isolate, Carboxymethyl Cellulose and
Oleic acid in predetermined quantities were dispersed
in 100 ml distilled water (DW), glycerol (3.2 gm)
was added as plasticizer followed by pH adjustment
with 1N Sodium Hydroxide solution to 8. The other
components like ascorbic acid and Sodium Benzoate
were also added as per the formulations shown in
Table 1 and coded as A,B and C. The solutions were
then heated with constant stirring on heating mantle
at 80-85oC temperature for 15 min. Tomatoes were
dipped in different coating solutions for 30s, the
excess coating was drained and the coated tomatoes
were kept for surface drying under natural convection
for 12± 2 hrs. Tomatoes dipped in distilled water
were used as a control. After the coating process,
tomatoes were stored at ambient conditions at a
temperature of 35 ± 3 deg Celsius and RH of 70 ± 5
per cent for 9 days. For each treatment 20 samples
were coated and three replications per treatment were
analyzed after 1, 3, 5, 7 and 9 days of storage.