MSc

The study entitled "Digestibility of carbohydrates in selected
pulses" is an assessment of the digestibility of carbohydrates of selected
pulses, processed and cooked in different forms. The influence of
different processing and cooking techniques on the carbohydrate
constituents and inhibitory constituents were also ascertained.
The pulses selected were cowpea, blackgram, redgram, greengram,
soyabean and bengalgram. The pretreatments administered on the fresh
samples were soaking in plain water for six hours (T 1)' soaking in plain
water for three hours (T 2) and soaking in water with NaHC03 for three
hours (T 3). Processing techniques administered on fresh samples as well
as pretreated samples were. germination (T 4)' fermentation (T 5) and
grinding (T 6). Cooking treatments administered were boiling (T 7)'
steaming (T 8)' cooking under pressure (T 9) and roasting (T IQ).
Among the untreated pulses analysed, the r-eadily available
carbohydrates in the form of sugars were found to be very low (7.00 to
13.86 g per cent). Starch content of pulses were ranging from 10.30 g
to 51.60 g per cent.

2
Pretreatments (soaking)were found to influence the starch content.
In this study, processing and cooking treatments had a negative influence
on the starch content of pretreated pulses. Among the different cooking
treatments, cooking under pressure revealed the greatest effect on the
reduction of starch.
Pulses soaked for three hours had higher values for carbohydrate
constituents.
Processing administered on different pulses were found to enhance
their sugar content.
A comparison of cooking treatments administered on all the
samples of processed pulses revealed the advantages of steaming and
roasting methods in retaining the carbohydrate constituents in all the
S
pules. TSS, RS, NRS and starch were lowered considerably when the
A
pulse samples were pressure cooked.
In the untreated pulses analysed, the constituents like protein
(22.23 g per cent to 42.70 g per cent), fibre (1.60 g per cent to 13.29 g
per cent) and phytate (130.50 mg per cent to 377.94 mg per cent) were
found high.
Different processing and cooking treatments had an influence on
the inhibitory constituents of pulses. The protein content of the pulses
in general were found to enhance after pretreatments. However, soaking
with NaHC03 resulted in a reduction in protein.

3
A companson among the three processing methods in the pulse
samples soaked by all the three methods revealed protein enhancement
in the order of germination followed by fermentation and grinding.
A comparison of the cooking treatments revealed the advantages
of steaming and roasting methods in retaining the protein. However.
boiling caused reduction in protein followed by cooking under pressure
probably because of the vigorous shaking of the pulse samples during
cooking.
Different pretreatments, processing and cooking treatments were
found to have an influence on the fibre content in all the pulses. There
was reduction in fibre after pretreatments, processing and cooking.
Samples soaked with NaHC03 for three hours and cooked had the highest
fibre content and the samples soaked for six hours had the lowest fibre
after cooking under pressure.
The phytate content in the pulses were found to be influenced by
pretreatments, processing and cooking treatments. Germinated samples
had the lowest phytate content. Among the germinated samples, the
samples germinated after soaking for six hours indicated to have the
lowest phytate content and the sample soaked for three hours without
NaHC03 was found to have the highest phytate content.
Cooking under pressure brought the maximum reduction in phytate
content in all the pulses.



4
In the present study, pulses untreated as well as treated in different
forms were subjected to in vitro digestion with alpha-amylase. This
enzyme hydrolysis starch to yield maltose.
Among the untreated pulses analysed, the rate of alpha-amylolysis
was highest in greengram and lowest in soyabean.
Among the pretreated samples also, the rate of starch digestibility
was lowest in soyabean.
Among the pretreated and processed samples, the maximum effect
on digestibility was caused by fermentation in the case of samples soaked
for six hours. When the samples soaked for three hours without NaHC03
was compared, the maximum effect was caused by fermentation followed
by germination and grinding. Among the samples soaked for three hours
with NaHC03, the maximum effect was caused by germination followed
by fermentation and grinding.
Cooking brought about a reduction in the in vitro digestibility of
starch the maximum after cooking under pressure. Rate of alpha-
amylolysis was found to be lower in all the treated and cooked pulses,
when compared to untreated and cooked ones, probably because of the
partial hydrolysis of starch during processing viz., germination,
fermentation and grinding.