WO2008072252A1

WO2008072252A1 - A process for preparation of ready-to-eat puffed (expanded) product from minor cereals

Info

Publication number: WO2008072252A1
Application number: PCT/IN2007/000450
Authority: WO
Inventors: Shivanna Meera Manchanahalli; Rambahadur Ushakumari Singh; Gurusiddappa Malleshi Nagappa
Original assignee: Council Of Scientific & Industrial Research
Priority date: 2006-12-15
Filing date: 2007-09-28
Publication date: 2008-06-19

Abstract

A process for the preparation of ready-to-eat puffed (expanded) minor cereals comprises the steps of : (a) cleaning grains; (b) grading to obtain uniform sized grains; (c) soaking the millets in water at 28-30deg C for a period of 8-30 hours in order to obtain sprouts; (d) soaking the sprouts in water at 30-70 deg. C for 14-12 hours; (e) steaming the sprouted grains under a pressure of 2.0 kg/sq.cm for 5-30 minutes in order to obtain processed grains; (f) drying the processed grains to a moisture content of 10-14 percent; (g) polishing the processed grain in order to remove seed coat and bran; (h) drying the polished grains to a moisture content of 5-13 percent; and (i) treating the dried polished grains at about 240-260 deg C for 45 seconds in order to obtain the puffed (expanded) minor cereals.

Description

"A PROCESS FOR PREPARATION OF READY-TO-EAT PUFFED (EXPANDED) PRODUCT FROM MINOR CEREALS"

Field of the Invention The present invention relates to preparation of value added product from cereals. The present invention particularly relates to a process for the preparation of ready-to-eat puffed (expanded) product from minor cereals.

Background of the Invention Millets are Minor cereals such as pearl millet, finger millet, little millet etc. are nutritious and are of value especially in the semi-arid-tropics because of their short growing season and higher productivity under heat and drought conditions and are generally cultivated with minimum agricultural inputs. They are nutritionally superior to major cereals such as rice and wheat, since they are good sources of carbohydrates, protein, dietary fiber and micronutrients. Traditionally millets are pulverized to whole meal and are used in the form of unleavened pancake, dumpling, thin porridge etc.; however, processing and diversification of these millets for other food uses and value added products have not been fully exploited. Even though potential of millets for preparation of ready-to-eat foods exists, very little effort has gone on these aspects of millets.

Processing of expanded or puffed cereals has been known since several centuries. Methods involving high temperature short time treatments have been applied to prepare puffed or popped or expanded cereals and legumes. Puffing gelatinizes the starch and produces ready-to-eat products and such products are commonly used as snack, breakfast food or as key ingredients in snack formulations. Popped cereals or millets are crisp and crunchy foods with desirable aroma and are highly appreciated for their lightness and adaptable for mixes (Malleshi and Desikachar, 1981 ; Chandrasekhar and Chattopadhyay, 1990; Mariotti, Alamprese, Pagani and Lucisano, 2006). While popping is largely followed for most of the cereals and also to Bengal gram, preparation of expanded cereals is mostly confined to rice. Although popping is a simple technique of adjusting the grain moisture and subjecting the tempered grains to HTST treatment, it has many drawbacks, the major being the retention of bran which affects consumer acceptability. The uneven appearance of the popped product does not permit coating and hence restricts its utilization in confectionary. The other disadvantage of popping of grains is that it is highly dependent on the variety and endosperm texture and morphology of the grain. The starch in the popped millets is sometimes not fully gelatinized due to hard and thick seed coat and hence restricts the use of popped millets in ready mix formulations. During the process of popping no doubt the seeds expand, but the endosperm of popped grains has a soggy texture because of its exposition to atmosphere which absorbs moisture and removal of the adhering seed coat is not possible from the popped products and hence lowers the consumer appeal. (Chinnaswamy, R. 1993, Carbohydrate Polymers, 21: 157-167). However, during the preparation of expanded cereals the process involves parboiling or steaming to gelatinize the starch followed by milling for dehusking and debranning and later subjecting the grains to HTST treatment. Rice being mainly starchy cereal is more suited for this process and hence expansion or puffing process is confined to riGe which shows very good expansion volume. However millets, which are known to possess rigid starch-protein interaction are generally popped by HTST treatment as whole kernels along with seed coat.

The process of preparation of expanded products from millets similar to rice is not simple and just parallel because unlike rice which contains more than • 80% of starch, the millets contain a substantial proportion of non-starchy polysaccharides, lipids and proteinacious matter. Besides, the organization of starch granules in millets, endosperm is very compact compared to rice. If the milled millets are directly subjected to high temperature and short time treatment, the resulting expansion ratio will be hardly 2 to 2.5 times and the product will be hard and gets charred resulting in very low acceptability. Very few reports are available which deals with expansion of millets for which reference may be made to the following studies. Reference may be made to a study by (Suhendro, E. L., McDonough, CM., Rooney, L.W. Waniska, R.D. and Yetneberk, S. 1998 Cereal Chem., 75: 187-193) where in sorghum grains were processed to prepare expanded product by cooking the grains extensively in lime to remove the pericarp and to loosen germ, the grains were later dried and subjected to HTST to prepare expanded sorghum. The main draw back of the process is that cooking results in extensive solid loss and the expansion ratio is hardly 2.5 times. Reference may be to another study by N. G. Malleshi and S. R. Usha Kumari Patent No WO 2005063048/DEL/385/04 wherein finger millet has also been processed to. prepare expanded product. In this study, parboiled finger millet grains are decorticated to remove seed coat and tempering and steaming prior to mechanical impact soften the grains. The main draw back of the process is that; it requires precise preconditioning and flattening the grains by mechanical impact to a particular shape factor involving specific thickness to diameter ratio. The process requires roller flakers or similar machinery to achieve this, which may not be generally available. Development of a process of expansion or puffing millets could lead to better ways of their widespread utilization. This enables the utilization of their nutritional and health benefits such as high levels of micronutrients, dietary fibers and antioxidant compounds, even to the non- traditional consumer (Mariotti, M., Alamprese, C, Pagani, MA and Lucisano, M. 2006, J. Cereal Science, 43: 47-56). Reference may be made to another study by Nandita kar, Srivastsav,

P.P., Jain, R. K. and Suresh Prasad Technology for production of popped and puffed Kodo millet, 2004 All India Coordinated Research Project on Post harvest Technology (ICAR) Post Harvest Technology Centre, Department of Agriculture and Food Engineering, Karagpur, wherein grains were parboiled by soaking in water (100 ° C) followed by steaming. The main drawback is that the study does not address the feasibility of this process with respect to millets other than Kodo millet, the other draw back is that the texture, colour and other functional properties of the puffed product has not been studied.

Objects of the Invention

In view of this, the main objective of the present invention is to provide a process for the preparation of a ready-to-eat expanded product from minor cereals with acceptable colour, aroma and other functional properties and retaining its original shape. Another object is to modify the endosperm texture of the millets by in vivo biotransformation without using external source of chemical, enzyme or mechanical force so that the products expands to its full capacity. Yet another object is to process the millets grains to enable preparation of puffed or expanded, ready-to-eat products.

Yet another object is to provide a cost effective process for the preparation of ready-to-eat puffed products for the minor cereals, preferably with nutritional improvement.

Detailed description of Invention:

Accordingly the present invention provides a process for the preparation of ready-to-eat puffed (expanded) minor cereals, which comprises the steps of: (a) cleaning grains to remove obnoxious and foreign material;(b) grading to obtain uniform sized grains;(c) soaking the millets in water at a temperature in the range of 28-30deg C for a period in the range of 8-30 hours in order to obtain sprouts;(d) soaking the sprouts in water at a temperature in the range of 30-70 deg. C for a period in the range of 14-12 hours;(e) steaming the sprouted grains under a pressure of 2.0 kg/sq.cm for a period in the range of 5-30 minutes in order to obtain processed grains;(f) drying the processed grains to a moisture content in the range of 10-14 percent; (g) polishing (pearling) the processed grain obtained in the step in order to remove seed coat and bran;(h) drying the polished grains to a moisture content in the range of 5-13 percent; AND (i) treating the dried polished grains obtained in the step (h) at a temperature of about 240-260 deg C for a period of about 45 seconds in order to obtain the said ready-to-eat puffed (expanded) minor cereals (millets).

In different embodiments cereals(millets) used are selected from the group consisting of pearl millet, finger millet, little millet etc.,

In an embodiment pearl millet used is selected from the group consisting of any variety, cultivar, breed, hybrid and transgenic pearl millet.

In another embodiment finger millet used is selected from the group consisting of any variety, cultivar, breed, hybrid and transgenic finger millet. In yet another embodiment wherein little millet used is selected from the group consisting of any variety, cultivar, breed, hybrid and transgenic little millet.

In another embodiment, ready-to-eat puffed (expanded) minor cereals

(millets) obtained has total sugar content in the range of 10-20 percent.

In yet another embodiment, ready-to-eat puffed (expanded) minor cereals (millets) obtained is used for preparation of snacks, health food formulations such as health bars, preparation of thickener in soup and is used as adjuncts in confectioneries.

In an embodiment of the present invention, millet species used may be pearl millet, finger millet, and little millet irrespective of the variety or location of their cultivation.

In another embodiment of the present invention, grains may be steeped for 6-18 h and allowed to germinate for 8 to 24h,

In yet another embodiment of the present invention, the germinated grains may be subjected to steam for 5 to 30 min at atmosphere or under pressure.

In still another embodiment of the present invention, the steamed grains may be dried to 8-16% moisture content by exposing to the sun or mechanical drier.

In still another embodiment of the present invention, the dried grains may be polished to remove 5 to 8% of the bran preferably in an emery polisher.

In still another embodiment of the present invention, the milled grains are subjected to HTST(high temperature and short time) using hot air, sand or salt as heat transfer media or using gun puffing unit, or by contact heat in a rotary grain roaster. Novelty

The novelty and inventive steps of this invention lies in the fact that the process makes use of germination of the grain to elaborate the hydrolytic enzyme that partially hydrolyze the cell walls and exposes the starch granules. The partially hydrolyzed starch is completely gelatinized by hydrothermal treatment thus making it possible to dehusk and debran germinated millet grains. Since the processed millet grains are dried to safe moisture content (5-10%) it can be stored and puffed as and when required by the processor. The processes of germination as well as hydrothermal treatment improve the nutritional and food quality of the products. This is altogether a new process, which help the millet grains to expand to its full capacity and this method is not followed hitherto.

Any minor modifications / changes / improvement, which could be apparent to the person familiar in the field of art of this invention, also are included in the scope of this invention.

The following examples are given by way of illustrating the present invention and therefore should not be construed to limit the scope of the invention.

Example 1

Two kilograms of pearl millet was cleaned and graded manually to obtain uniform grains. The grains were soaked in water at ambient conditions for 12 h, the excess water was drained off and the grains were spread in trays and the grains were steamed in an autoclave for 15 min at 1 kg pressure. The steamed grains were dried in shade to 12% moisture content and dehusked and debranned in an abrasive polisher to 8% degree of decortication and subsequently dried to 8% moisture content. The dried grains were subjected to hot air at a temperature of 280° C for about 45 seconds. Example 2

Two kilograms of pearl millet was cleaned and graded manually to obtain uniform grains. The grains were soaked in water at ambient conditions for 12 h, the excess water was drained off and the grains were spread in trays at 3 cm thickness over moist cloth covered with another moist cloth and allowed to germinate for 24 h at ambient conditions in shade. The germinated grains or sprouts were soaked in water under ambient conditions for 4 h, excess water was drained and the grains were steamed in an autoclave for 15 min at 1 kg pressure. The steamed grains were dried in shade to 12% moisture content and dehusked and debranned in an abrasive polisher to 8% degree of decortication and subsequently dried to 8% moisture content. The dried grains were subjected to hot air at a temperature of 280° C for about 45 seconds to obtain expanded grain. The volume expansion of the expanded grain was recorded. Expansion ratio = Volume of expanded grains Volume of decorticated grains

Example 3

Two kilograms of finger millet was cleaned and graded manually to obtain uniform grains. The grains were soaked in water at ambient conditions for 12 h, the excess water was drained off and the grains were spread in trays at 3 cm thickness over moist cloth covered with another moist cloth and allowed to germinate for 24 h at ambient conditions in shade. The germinated grains or sprouts were soaked in water under ambient conditions for 4 h, excess water was drained and the grains were steamed in an autoclave for 15 min at 1 kg pressure. The steamed grains were dried in shade to 12% moisture content and dehusked and debranned in an abrasive polisher to 8% degree of decortication and subsequently dried to 8% moisture content. The dried grains were subjected to hot air at a temperature of 280° C for about 45 seconds to obtain expanded grain. The volume expansion of the expanded grain was recorded. Expansion ratio = Volume of expanded grains

Volume of decorticated grains Example 4

Two kilograms of little millet was cleaned and graded manually to obtain uniform grains. The grains were soaked in water at ambient conditions for 12 h, the excess water was drained off and the grains were spread in trays at 3 cm thickness over moist cloth covered with another moist cloth and allowed to germinate for 24 h at ambient conditions in shade. The germinated grains or sprouts were soaked in water under ambient conditions for 4 h, excess water was drained and the grains were steamed in an autoclave for 15 min at 1 kg pressure. The steamed grains were dried in shade to 12% moisture content and dehusked and debranned in an abrasive polisher to 8% degree of decortication and subsequently dried to 8% moisture content. The dried grains were subjected to hot air at a temperature of 280° C for about 45 seconds to obtain expanded grain. The volume expansion of the expanded grain was recorded.

Table 1. Volume of expanded grains parboiled as such and after germination (volume/volume)

Table 2. Characteristics of expanded pearl millet

Flow chart illustrating the process for the preparation of ready- to-eat puffed (expanded) ready-to-eat millet

MILLETS

Soak in water under ambient conditions

Germinate the grains

(24ιh)

Soak the germinated grains in water

Hydrothermal Treatment

Drying and polishing to remove bran/seed coat

Decorticated millet

HTST treatment

Expanded ready-to- eat millet

Advantages of the present invention are:

1. The process enables the production of expanded millets from any species of minor cereals irrespective of the variety and agroclimatic conditions of cultivation

2. The process retains the germ in the expanded product and in view of that the expanded product contains higher proportion of fat, a rich source of energy

3. The process utilizes natural process that modifies the endosperm thus eliminating mechanical or chemical methods for modification.

4. The process permits wide range of moisture adjustment prior to expansion and permits storage of the processed ready-to-expand millets and offers puffing at convenience.

5. The process partially predigest the cereals, thus enabling the consumer to access easily digestible, energy rich food in a ready - to- eat form, as such or after seasoning with sweet or savory adjuncts.

6. The process also permits to utilize the partially processed millets to convert to flakes, semolina and such other products suitable for Indian traditional dishes.

7. Expanded millets can be an ideal base for snack bars, health bars since the product retains crispiness even when embedded in the sugar or jaggery or cocoa mass and as base for sweet or savory snack food. 8. The process improves minerals and vitamins for easy availability as most of the antinutritional factors are reduced as a result of processing. 9. Since the process requires simple equipments it can be adopted by small scale and cottage level industries. 10. The process is new of its kind for millets and produces the millets in a convenient use form and may help in the diversification of the under utilized millets.

Claims

1. A process for the preparation of ready-to-eat puffed (expanded) minor cereals, which comprises the steps of: (a) cleaning grains to remove abnoxious and foreign material;

(b) grading to obtain uniform sized grains;

(c) soaking the millets in water at a temperature in the range of 28-30deg C for a period in the range of 8-30 hours in order to obtain sprouts; (d) soaking the sprouts in water at a temperature in the range of 30-70 deg, C for a period in the range of 14-12 hours; (e) steaming the sprouted grains under a pressure of 2.0 kg/sq.cm for a period in the range of 5-30 minutes in order to obtain processed grains; (f) drying the processed grains to a moisture content in the range of 10-14 percent; (g) polishing (pearling) the processed grain obtained in the step in order to remove seed coat and bran;

(h) drying the polished grains to a moisture content in the range of 5-13 percent; AND

(i) treating the dried polished grains obtained in the step (h) at a temperature of about 240-260 deg C for a period of about 45 seconds in order to obtain the said ready-to-eat puffed (expanded) minor cereals (millets).

2. A process according to claim 1, wherein cereals(millets) used are selected from the group consisting of pearl millet, finger millet, little millet etc.,

3. A process according to claims 1 and 2, wherein pearl millet used is selected from the group consisting of any variety, cultivar, breed, hybrid and transgenic pearl millet.

4. A process according to claims 1 and 2, wherein finger millet used is selected from the group consisting of any variety, cultivar, breed, hybrid and transgenic finger millet.

5. A process according to claims 1 and 2, wherein little millet used is selected from the group consisting of any variety, cultivar, breed, hybrid and transgenic little millet.

6. A process according to claims 1-5, wherein ready-to-eat puffed (expanded) minor cereals (millets) obtained has total sugar content in the range of 10-20 percent.

7. A process according to claims 1-6, wherein ready-to-eat puffed (expanded) minor cereals (millets) obtained is used for preparation of snacks.

8. A process according to claims 1-6, wherein ready-to-eat puffed (expanded) minor cereals (millets) obtained is used for preparation of health food formulations such as health bars.

9. A process according to claims 1-6, wherein ready-to-eat puffed (expanded) minor cereals (millets) obtained is used for preparation of thickener in soups.

10. A process according to claims 1-6, wherein ready-to-eat puffed (expanded) minor cereals (millets) obtained is used as adjuncts in confectioneries.