The Lipoxygenase (LOX) enzyme is found in a variety of plant products particularly
legumes, such as soybeans, mung beans, navy beans, green beans, peas, and
peanuts, and also cereals, such as rye, wheat, oat, barley, com and rice
bran. It causes off¬flavour and off-odour in foods. As a food grade product,
the beans and bran should be of good keeping quality and high industrial
value, in which all the components that may cause deterioration, must be
removed or their activity arrested. Important in this respect is that inactivation
of lipase and LOX enzymes must be complete and irreversible. At the same
time, the valuable nutrients must be preserved. In addition to LOX, some
legumes and cereal products, especially rice bran, endogenously contain the
lipase enzyme which hydrolyses the primary lipids triglycerides (TG). The
resulting fatty acids increase bran acidity and reduce pH, as a result of
which off- flavour and soapy taste are produced, and the functional properties
change. Most of the thermal and chemical methods are used which are inadequate
and unsatisfactory or impractical. The existing technologies like wet milling,
pre-soaking in hot water with NaHC03, high hydrostatic pressure (lOO-200MPa),
Ultra High Temperature (at 140°C), Microwave-heating etc. that are used
to inactivate LOX and trypsin inhibitor in beans and brans have disadvantages
like severe processing conditions damaging valuable components of bran, (2)
substantial moisture removal, and (3) incomplete and reversible enzyme inactivation
(the enzyme resumes its activity on contact with air). Thus in the invention
the initial preheat temperature, pressurisation levels, pressurisation time
periods, pause time (the time for which the steriliser is in the pressurized
or depressurized condition) between pressurization and depressurization and
the sequences of pressurisation¬ depressurisation, are judiciously selected
to yield a product with inactivated enzyme and which is sterilized, while
substantially preserving the nutritional value, colour, texture with enhanced
shelf life (including enhanced storage without refrigeration).
Thus in accordance
with this invention the said product has the following characteristic features:
1) Legumes and Cereal products with inactivated enzymes (lipoxygenase,
trypsin
inhibitor and lipase).
2) Lipoxygenase and trypsin inhibitor is completely inactivated.
3) The treated products show no further enzyme activity.
4) Up to 80% of initial Lipoxygenase is deactivated in the final product.
5) It is devoid of any off-flavours.
6) It has a pleasant sweetish taste with a smooth mouth feel as assessed
by trained
panel.
7) The product is sterilized.
8) It is auto-dehulled.
9) The product is tenderized.
10) The product can be used as a ready-to-use stock for preparing other
items (e.g. the treated soybeans can be used to get soy flour, soymilk,
tofu etc.)
11) The product can also be consumed directly and also safe for growing
children.
12) The oil extraction efficiency in the treated product increases, giving
better
yields.
13) The product shelflife is 30-45days.
14) The product itself or the other food items prepared from it are shelf-stable
without refrigeration
Indian patent application no. 540/MUM/2005 Patent grant no.
Inventors: A Chakraborty and M Mukhopadhyay
