| Summary: | Utilization of roasted white sesame seeds as a source of oil will produce
roasted sesame cakes as by products, which has a high protein content as high as
50%, depends on oil extraction method. Roasted sesame cake protein can be
isolated and hydrolyzed in order to improve functional properties. The
improvement of functional properties of proteins can be performed by enzymatic
hydrolysis. One of the proteolytic enzymes that can be used is bromelain with a
wide hydrolysis specifity at four amino acid residues. Each enzyme has a specific
optimum temperature and pH for its catalytic reaction, but it is not known if the
likelihood of enzyme/substrate (E/S) ratio is large or small, and hydrolysis time is
short or long. This study aimed to determine the effect of bromelain addition in
various concentration (E/S ratio) and hydrolysis time on the degree of hydrolysis,
molecular weight, and also functional characteristics of roasted sesame cake
protein hydrolysates.
White sesame seeds were roasted at 180oC for 30 minutes. The oil was
removed by pressing and defatting using technical n-hexane. The protein of
deffated flour of roasted sesame cakes were isolated by dissolving the protein at
pH 11 and precipitation at pH 3.5. Protein isolates were hydrolyzed by bromelain
at pH 6 and temperature 45°C with constant stirring. The E/S ratios were 1% and
5% (w/w) and the hydrolysis times were 10, 20, 30, 60, and 120 minutes.
Hydrolyzate were analyzed for degree of hydrolysis, molecular weight, soluble
protein content, emulsifying activity index, emulsifying stability index, and also
capacity and stability of foam formation.
The results showed that the increasing of E/S ratio from 1% (w/w) to 5%
(w/w) increased degree of hydrolysis for 1.85 folds
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