Physicochemical and Textural Characteristics of Expanded Finger Millet

Abstract

The decorticated finger millet was subjected to high temperature short time treatment to prepare the expanded product. The product with 5.64 expansion ratio showed a cream color and was very light in weight with a bulk density of 0.14 g/ml and contained 4.69 g/100 g protein, 0.74 g/100 g ether extractives, 72 g/100 g carbohydrates, 11 g/100 g dietary fiber, and 190 mg/100 g calcium. The expanded millet was a crisp product with very low compression values (2.14 N) and contained two thin concentric layers with a vacuole inside. The pasting profile of the product revealed substantial initial viscosity and negligible set back viscosity. The functional and textural properties indicated the possible usage of the product in snacks and supplementary foods.

Keywords:

• Finger millet
• Expansion
• Functional properties
• Nutrient composition

INTRODUCTION

Popping of cereals and grain legumes is one of the traditional food-processing methods followed worldwide. It is a simple and least expensive method adapted for preparation of ready-to-eat, aerated, porous, and crisp textured product.[1] The process of popping in cereals is normally classified into ‘puffing’ and ‘expansion,’ wherein puffed cereals are produced from grains in their native form and the expanded cereals are prepared from parboiled and decorticated grains. Preparation of both puffed and expanded grains is based on high temperature short time treatment (HTST), wherein the steam generated inside the endosperm causes its expansion. In the case of puffing, the seed coat of the kernel acts as a barrier for escape of the steam causing pressure leading to the sudden explosion of the endosperm, whereas in case of expanded products, the starchy endosperm containing pregelatinized starch enables building up of pressure and expands uniformly into all the directions.[2] The puffed grains are uneven shaped, whereas the expanded grains largely retain the shape of the native grains. The classic examples of puffed and expanded cereals are popcorn and expanded rice, respectively.

Expanded cereals offer many advantages over the puffed cereals. Since they are prepared from parboiled and decorticated grains, they are free from the seed coat content and also free from many of the anti-nutritional principles associated with unprocessed whole grains. The expanded grains are easily digestible and are amenable for improving taste and aroma by coating with spice and condiments. In view of this, the expanded cereal can be used for preparation of a variety of ready-to-use snack foods. On the other hand, the puffed cereals contain a bran layer and poorly expanded portion adjacent to the embryo. In view of this, the puffed cereals are of poor sensory as well as keeping quality. In recent years, snack food consumption is increasing worldwide and there is a growing demand for a variety of ready-to-eat snacks and breakfast cereals.[3] Therefore, a search for new and novel products is carried out globally.

Finger millet, one of the important minor cereals of the tropics, is unique among the cereals because of its richness in calcium, dietary fiber, and polyphenols.[4] Moreover, its protein is a good source of sulfur-containing amino acids.[5] Although the millet is a staple for a large segment of the Indian and African population, its food usage is limited to only flour-based products. Recently, Central Food Technological Research Institute (CFTRI), Mysore, has developed a process for preparation of expanded finger millet[6] similar to expanded rice, which has very high potential for use as snacks and allied food products. The expanded millet is the first of its kind from finger millet, and there is no information available on its quality characteristics. Hence, the nutrient composition, textural, and functional properties of the expanded millet were determined, so that its utilization could be explored in convenience foods, snacks, health bars, museli, supplementary foods, and also in some of the functional foods for the target population. This eventually may help for its widespread marketability and improve the millet economy. Hence, the nutrient composition; some of the functional properties, such as water and fat absorption, solubility, and swelling characteristics; pasting profile; and the textural features of the expanded millet were determined.

MATERIALS AND METHODS

A popular variety of finger millet (GPU 28), procured from the University of Agricultural Sciences, Bangalore, Karnataka, was processed to prepare decorticated millet following the method developed at CFTRI, Mysore.[7,8] The decorticated millet was processed for preparation of expanded millet, which involved equilibration of the grains to 40% moisture content, deshaping and subjecting to high temperature short time treatment.[9] The expanded millet was pulverized in a communition mill (Universal Engineering Works, Mysore, India) to prepare the whole meal (-250 μm). The expanded millet and the decorticated millet and their meals were equilibrated and used for the studies.

Physical Properties

Color and bulk density

The color of the expanded and decorticated grains as well as their meals was measured in accordance with CIE L*, a*, b* color space system based on the tristimulus values. The samples were placed on the 1-in. diameter port of the color measuring system (Minolta, Osaka, Japan) and the lightness (L*), redness (+ve a*), yellowness (+ve b*), and the magnitude of total color difference (ΔE) values were determined. The volume of 100 g of the grains and the meals was measured in a measuring cylinder (250 ml) after tapping the cylinder on a wooden plank until no visible decrease in volume was noticed, and based on the weight and volume, the apparent (bulk) density was calculated.[10]

Hardness

The hardness of the expanded and decorticated grains was measured using a food texture analyzer (Stable Microsystems, Model TA-HDi, Surrey, UK) with a 50-kg load cell, by recording maximum force required to cause 80% compression of the individual grains. The pre, test, and post cross head speeds were maintained at 1.66, 1.66, and 2.00 mm/s, respectively. The initial peak and maximum peak force (N) and also the slope (N/s) were measured from the force-deformation curve[11] and the average value of 10 individual determinations was reported.

Nutrient Composition

The nutrient composition and the soluble and insoluble total dietary fiber of the meals were determined following the AACC[12] and rapid enzymatic assay[13] methods, respectively. The ash content of the millet was dissolved in dilute HCl and used for estimation of calcium by precipitating as calcium oxalate.[14]

Water Absorption Capacity and Water Solubility Index

One gram of the meal taken in a graduated centrifuge tube was mixed with 10 ml of water and incubated for 30 min in a water bath maintained at 30°C followed by centrifugation at 1750× g for 25 min. The supernatant was decanted and the weight of the residue was noted to calculate the water absorption capacity.[15] The supernatant was transferred into a pre-weighed petriplate and evaporated to dryness on a water bath, dried in an air oven maintained at 105°C for 5 h. Based on the dry weight and the weight of the residue, the percentage of solubles was calculated. The experiment was repeated at 97°C also.

Oil Absorption Capacity

To 1 g of each of the meals taken in graduated centrifuge tubes, 10 ml of double-refined peanut oil was added, mixed well, and allowed to stay for 30 min at ambient temperature. The contents were centrifuged at 1750× g for 25 min, the supernatant was decanted off, and weight of the residue was noted to calculate the oil absorption capacity.[16]

Viscosity

A 10% (w/v) slurry prepared by dispersing 10 g of meals in 90 mL of distilled water was mixed well, equilibrated for 30 min with occasional stirring at 30°C and the viscosity of the slurry was measured in a Brookfield viscometer (Model RV, Brookfield Engineering Inc., Stoughton, MA, USA) using appropriate spindles to record cold paste viscosity. Subsequently, the samples were heated to boiling in a water bath till the slurry was cooked, then cooled to 30°C and the cooked paste viscosity was measured.[17]

Pasting Characteristics

A 12% aqueous slurry (w/v) was transferred to the heating bowl of the Brabender visco-amylograph (Model No. 803202, Brabender, Duisburg, Germany) and heated to raise the temperature at the rate of 7.5°C per min from 30 to 92°C maintained for 1 min at 95°C, then cooled to 50°C at the same rate. The changes in the viscosities during heating, cooking, and cooling were recorded.

Microscopic Examination

The expanded and decorticated millet kernels cut into two halves from the embryo end, were mounted on the stubs with the aid of scotch tape and gold coated (about 100 Ǻ) in a KSE 2AM Evaporation Seevac gold sputter (Polaron SEM Sputter Coating System, Hertfordshire, UK). The gold-coated samples were scanned in a LEO 435VP scanning electron microscope (Leo Electron Microscopy Limited, Cambridge, UK) and the selective portions depicting morphological features were photographed.

Carbohydrate Digestibility

The carbohydrate digestibility of the defatted samples was determined by enzymatic digestion.[18] The defatted samples (100 mg) were mixed with 10 mL water containing 0.1 mL of termamyl (Sigma, 9000-85-5, St. Louis, MO, USA) and heated in a boiling water bath for 15 min, cooled, and to that 15 ml of glycine HCl buffer (0.1 M, pH 2.2) was added followed by the addition of 15 mg of pepsin and incubated at 37°C for 2 h. The contents were neutralized with 0.2 N NaOH and 15 mL of phosphate buffer (0.05 M, pH 6.8) containing 15 mg of pancreatin (Sigma, 8049-47-6) was added and incubated at 37°C for 2 h. The pH of the reaction mixture was then lowered to 4.5 using dilute acetic acid and 15 mL of acetate buffer (0.05 M, pH 4.5) containing 15 mg of amyloglucosidase (Sigma, 9032-08-0) was added and incubated for 2 h at 55°C. The glucose released was estimated by using glucose oxidase reagent.

Protein Digestibility

To 1 g each of the defatted samples containing 15 ml of 0.1 N HCl, 15 mg of pepsin was added and incubated at 37°C for 3 h. The content was neutralized to pH 7 with 0.2 N NaOH and to that 7.5 ml of phosphate buffer (0.05 M, pH 8) containing 4 mg of pancreatin was added. The reaction mixture was incubated at 37°C for 24 h.[19] The contents were made up to 50 ml with water and centrifuged at 5000 rpm for 20 min. An aliquot of the supernatant was taken and analyzed for its protein content following Lowry's method.[20]

Carbohydrate Profile

The carbohydrates of the defatted samples were fractionated following gel permeation chromatography. To 50 mg of the defatted samples, 4 ml of 90% dimethyl sulphoxide was added. The contents were boiled in a water bath for 15 min, centrifuged, and an aliquot of the extract containing 10 mg carbohydrates was fractionated by ascending chromatography on a Sepharose CL-2B (Pharmacia Fine Chemicals, Uppsala, Sweden) column (1.6 × 60 cm) using a peristaltic pump at a flow rate of 15 ml h⁻¹, using double-distilled water containing 0.02% sodium azide as eluent. About 150 ml of the eluent in 3-ml aliquots was collected and the carbohydrate content of the eluted material was estimated following the phenol-sulphuric acid method[21] and the elution profiles were determined as described by Chinnaswamy and Bhattacharya.[22]

Lipid Profile

To 40 mg of the lipids extracted from the meals using petroleum ether (60–80°C), 1 ml of dichloromethane/benzene followed by 2 ml of 1% sodium methoxide solution (1 g sodium dissolved in 100 ml of anhydrous methanol) were added. The contents were heated to 50°C for 10 min, cooled and mixed with 0.1 ml of glacial acetic acid, 5 ml of distilled water, and 15 ml of petroleum ether (40–60°C), sequentially. The fatty acid profile was determined by gas chromatography (Model GC-15A, Shimadzu Corporation, Kyoto, Japan) using a 15% diethylene glycol succinate column.[23] All the data were analyzed using Origin 6.1 software (OriginLab Corporation, Northampton, US). The significant difference comparisons were done using T-test and the statistical significance was defined as P < 0.05.

RESULTS AND DISCUSSION

The expanded grains were of near spherical shape with mild translucency, except for the opaqueness at the portion adjacent to the embryo (Fig. 1). The product was pearly and looked like a soap bubble and was of light cream color compared to light brownish color of the decorticated millet, which was evident from the significant decrease in the redness and yellowness values of the expanded millet (1.64 and 10.59) compared to the decorticated millet (3.82 and 12.87). The lightness value for expanded product was also higher (55.96) than that of the decorticated millet (53.32) resulting in a total decrease in ΔE value from 39.63 to 36.24 after expansion. During expansion of a cereal containing gelatinized starch, the steam formed inside the kernel transforms the starch into papery thin layers creating vacuoles in between. Probably, this transformation imparts a translucent appearance to the product. However, the meal from the expanded millet was comparatively less bright from its decorticated counterpart as is evident from the lower values for the L (70.29) and ΔE (23.76) compared to that of decorticated millet meal (76.31 and 17.76, respectively). However, the meal from the expanded millet was whiter than the expanded grains as such. During HTST treatment, the peripheral layer turns slightly yellowish due to contact with the hot salt, without substantially altering the color of the endosperm matter and thereby imparting slightly yellowish color to the grains. On pulverization, the yellow color largely disappears because of the comparatively whiter endosperm. Hence, the meal would appear whiter compared to the expanded grains (Table 1).

Figure 1 Photograph of expanded finger millet (color figure available online).

Table 1 The L*, a*, b*, and ΔE values for color of decorticated and expanded finger millet

		L	a*	b*	ΔE
Grains	Decorticated	53.32^a	3.82^a	12.87^a	39.63^a
	Expanded	55.96^b	1.64^b	10.59^b	36.24^b
Whole meal	Decorticated	76.31^a	1.23^a	10.82^a	17.16^a
	Expanded	70.29^b	1.79^b	12.51^b	23.76^b
Values followed by the different letters in a column are significantly different (P ≤ 0.05).

The average diameter of the expanded kernels was 5.23 ± 0.8 mm, nearly fourfold higher than the decorticated grain (1.5 ± 0.1 mm) with an apparent expansion volume of 7.1 ± 0.5 ml/g. It may be noted that the expansion ratio of finger millet is better compared to the other millets. The bulk density of the expanded millet (0.14 g/ml) was severalfold lower than the decorticated millet (0.80 g/ml). Even the product in the flour form also exhibited comparatively low bulk density (0.50 g/ml) than the decorticated millet meal (0.77 g/ml). This shows the fluffy nature of the expanded millet (Table 2).

Table 2 Physico chemical properties of decorticated and expanded finger millet

Parameter	Decorticated	Expanded
Diameter (mm)	1.5 ± 0.1^a	5.23 ± 0.8^b
Bulk density (g/ml)
Grains	0.80 ± 0.01^a	0.14 ± 0.01^b
Flour	0.77 ± 0.01^a	0.50 ± 0.01^b
Expansion ratio	—	5.64 ± 0.10
Expansion volume (ml)	—	7.10 ± 0.10
Viscosity 10% slurry (cP)
Cold paste	22.00 ± 0.70^a	110.00 ± 0.70^b
Cooked paste	463.00 ± 2.00^a	726.00 ± 1.00^b
Solubility (g%)
30°C	2.90 ± 0.10^a	3.40 ± 0.10^b
97°C	3.50 ± 0.1^a	3.80 ± 0.10^b
Swelling (g%)
30°C	306.00 ± 1.00^a	452.00 ± 1.00^b
95°C	496.00 ± 2.00^a	486.00 ± 1.00^a
Water absorption capacity (%)
Grains as such	—	152.00 ± 1.00
Flour	242.00 ± 1.00^a	240.00 ± 1.00^a
Oil absorption capacity (%)
Grains as such	120.00 ± 1.00^a	461.00 ± 1.00^b
Flour	167.00 ± 1.00^a	507.00 ± 1.00^b
Moisture (g%)	10.46 ± 0.07^a	10.00 ± 0.07^a
Ether extractives (g%)	0.77 ± 0.01^a	0.74 ± 0.02^a
Protein (g%)	4.70 ± 0.02^a	4.69 ± 0.02^a
Dietary fiber (g%)
Insoluble	7.80 ± 0.06^a	9.50 ± 0.05^b
Soluble	2.30 ± 0.01^a	1.80 ± 0.01^b
Carbohydrates	72.97 ± 0.1^a	72.15 ± 0.1^a
Minerals (mg%)	1.00 ± 0.03^a	1.12 ± 0.02^a
Calcium (mg%)	190.00 ± 2.00^a	190.00 ± 1.00^a
Carbohydrate digestibility (%)	78.00 ± 1.00^a	99.00 ± 1.00^b
Protein digestibility (%)	91.00 ± 1.00^a	97.00 ± 1.00^b
Values followed by the different letters in a row are significantly different (P ≤ 0.05).

The solubility index and swelling power of the expanded millet were typical to the expanded cereals. At 30°C about 3.4% of the millet was soluble and it almost remained constant even at 97°C. Similarly, the swelling power at 30°C (452%) and 97°C (486%) were also almost comparable (Table 2). However, there existed a considerable difference between the solubility and swelling power values of the expanded and decorticated millet at 30°C and that at 97°C is not very significant. Higher swelling power indicates its high water absorption capacity and its suitability for use as low calorie foods. The increase in solubility on expansion may be due to formation of low molecular weight carbohydrates as a result of thermal degradation during the HTST treatment, whereas a higher degree of swelling power could be due to high porosity of the matrix formed by gelatinization of starch during expansion and also could be due to the presence of dextrins.

The water absorption index for the expanded grains was 152%, whereas that of its meal was 240%. Normally, the expanded cereals contain fully gelatinized starch, which caused a drastic increase in its hydration characteristics compared to native or parboiled grains.[24] This property may also be gainfully utilized in improving the texture as well as shelf-life of bread if it is used as one of the ingredients for bread preparation. This could be possible as expanded millet flour may preferentially absorb the free water in the bread released during staling and may keep it soft and enhances its storage life.[25] The oil absorption capacity of the expanded millet (461%) and its flour was considerably higher (507%) than that of the corresponding decorticated millet samples (120 and 167%). This may be due to the porous nature of the product and also due to the presence of void spaces and air cavities.

The nutrient profile of the expanded millet was almost comparable to that of the decorticated millet, indicating no appreciable loss of nutrients during its preparation even though the grains are subjected to high temperature short time treatment. The expanded millet contained 4.69, 0.74, and 190 mg% of protein, ether extractives, and calcium, respectively, as against 4.7, 0.77, and 190 mg%, respectively, for the decorticated millet (Table 2). The dietary fiber content of the expanded millet was slightly higher (11.3%) than the decorticated millet (10.1%), which could be due to formation of resistant starch during the HTST treatment.

The carbohydrate digestibility of the expanded millet was 99% on starch basis compared to that of the decorticated millet (78%). The high percentage of digestibility and the quick digestion indicates that most of the starch is in an available form and has not undergone drastic retrogradation,[26] which normally occurs during hydrothermal treatment of cereals.[27] Similarly, the protein digestibility of the expanded millet is about 98% when compared to that of the decorticated millet (90%).

The textural profile of the expanded millet presented in Fig. 2, shows irregular force-deformation curve with a large number of smaller peaks. This reveals that the product is crisp and fragile as well as friable. The first peak force, the maximum force, number of major peaks, and the initial slope of the linear portion of the curve were determined as per Murthy and Bhattacharya.[28] On application of an external force, a typical cracking sound was heard, which indicated the crispness of the product. The force deformation curve showed two different zones, a sharp initial peak followed by a number of multiple peaks. The initial peak probably represents the initial resistance offered by the peripheral layer and the multiple peaks represent the crispness of the product as the grain fractures. Normally, the embryo does not expand to an appreciable level and the endosperm adjacent to the scutellum also exhibits a poor degree of expansion, which may be the reason for the total grain resistance against an applied force. The initial slope is conventionally called as firmness results out of the resistance offered by the whole grain.[29] The product exhibited very low initial peak and slope values (2.14 N and 8.53 N/s) (Table 3) and the total hardness of the product was severalfold lower than that of the decorticated millet.

Figure 2 Force deformation curves of expanded and decorticated finger millet (color figure available online).

Table 3 Textural parameters of decorticated and expanded finger millet

Parameter	Decorticated	Expanded
First peak force (N)	34.4 ± 7.6	2.14 ± 0.52
Slope of first peak (N/s)	264.7 ± 10.2	8.53 ± 2.33
Max. peak force (N)	161.3 ± 5.00	3.44 ± 0.74
The values in the different columns are significantly different at P ≤ 0.05.

The cold and the cooked paste viscosity of the millet at 10% slurry concentration determined both in Synchro-Lectric viscometer (Table 1) and the Brabender visoamylograph (Table 4) represented the properties of typical precooked cereals. Significant cold paste viscosity (110 cPs) observed for the expanded millet indicated the presence of high proportion of pregelatinized starch compared to the decorticated millet. This was also reflected by the significantly lower cooked paste viscosity of expanded millet. This is in line with the earlier observations on rice by Unnikrishnan and Bhattacharya.[30] The pasting profiles of expanded millet (Fig. 3) exhibited an initial viscosity of 133 BU, which is significantly higher than that of decorticated millet (69.3 BU). This indicates that the expanded millet is a completely gelatinized product similar to popped and expanded rice.[26] The peak viscosity of the expanded millet (359 BU) was much higher than that of the decorticated millet (194 BU). However, its set back viscosity was slightly less than the peak viscosity (Table 4). The viscosity observed at about 70°C could be due to the gelatinization of the very minor proportion of the ungelatinized starch, which may be present in the millet, but the negligible difference between the total set back and peak viscosity clearly indicated a very low level of retrogradation. This could be due to thermal degradation of some portion of starch to lower molecular weight dextrins. It is well known that the starch present in cereals undergoes gelatinization during puffing, however, the degree of gelatinization largely depends on the conditions of puffing.

Figure 3 Pasting profiles of expanded and decorticated finger millet.

Table 4 Pasting characteristics of decorticated and expanded finger millet

Parameter	Decorticated	Expanded
Peak viscosity (BU)	194 ± 1.2	359 ± 1.6
Hot paste viscosity (BU)	194 ± 1.3	270 ± 0.3
Cold paste (BU)	319 ± 1.6	369 ± 1.7
Breakdown (BU)	0	88 ± 0.6
Setback (BU)	109 ± 0.7	106 ± 1.2
Pasting temperature (°C)	69.3 ± 0.1	46.1 ± 0.1
The values in the different columns are significantly different at P ≤ 0.05.

The carbohydrate elution profile of the expanded millet indicated the presence of two main fractions, namely Fraction I and Fraction II (Fig. 4). Fraction I (considered as amylopectin) was the major peak, while Fraction II (considered as the amylose) was the minor peak.[22] The broadening of the II peak may be due to the thermal degradation of the starch into lower molecular weight dextrins during processing.

Figure 4 Carbohydrate profiles of the expanded and decorticated finger millet.

The fatty acid composition of the expanded millet is presented in Table 5 and the elution profile is presented in Fig. 5. The major fatty acids detected were oleic acid (61.68%) and palmitic acid (19.37%), while linoleic acid formed a minor component (2.14%). There was a substantial difference between the fatty acid profiles of expanded millet and the decorticated millet. The oleic acid content increased from 50 to 62%, but the palmitic and linoleic acid contents decreased from 26 to 19% and 20 to 2%, respectively, on expansion (Table 5). This shows that the heat treatment reduces the unsaturated fatty acids, mainly linoleic acid content substantially. Similar observations have been reported by Karkalas et al.[31] that during heat treatment the amylose complexes with the lipids, preferably with the linoleic acid. This phenomenon is also observed in the case of popcorn leading to a higher expansion ratio.[32]

Figure 5 Fatty acids profiles of expanded and decorticated finger millet.

Table 5 Fatty acid composition of decorticated and expanded finger millet

Fatty acid	Decorticated	Expanded
Palmitic (16:0)	26.18 ± 0.03	19.37 ± 0.02
Stearic (18:0)	0.12 ± 0.02	0.40 ± 0.02
Oleic (18:1)	50.43 ± 0.40	61.68 ± 0.40
Linoleic (18:2)	20.26 ± 0.20	2.14 ± 0.10
Linolenic (18:3)	2.60 ± 0.10	—
Aracheodoneic (20:0)	—	1.009 ± 0.10
The values in the different columns are significantly different at P ≤ 0.05.

The scanning electron microscopic examination revealed the absence of a honeycomb-like structure normally found in puffed cereals except for a small portion near the embryo. The transverse section of the expanded product revealed the presence of two concentric spheres fused at the embryo end. The portion near the embryo was opaque and the rest of the material was translucent. Probably, the hydrothermal treatment to the native grain transforms the starchy endosperm into a coherent mass, which on HTST treatment causes expansion in all directions forming a spherical-shaped product. The scanning electron photomicrographs of the product presented in Fig. 6 represent the surface topography of the expanded grain and also its transverse sections. The expanded grain looked almost like a bulged sphere (Fig. 6a) with an uneven surface. A magnified image at 3KX (Fig. 6b) revealed that the surface of the expanded grain had uneven ridges and furrows even though it appeared to be smooth to the naked eye. But interestingly, the transverse section of the grain (Fig. 6c) exhibited a big air vacuole or cavity inside, which forms almost 80% of the total kernel size, is made up of a thin starchy film, and is proportional to the expansion ratio of the millet. This inner starchy film was surrounded by an outer concentric sphere cross-linked by a matrix of several air cavities of irregular size. The matrix of air cavities is prominent towards the embryo (Fig. 6d). Due to the pretreatment, the gelatinized starch explodes into a thin film creating a big vacuole inside the grain during HTST treatment. This typical phenomenon is not reported in the case of expanded rice, wherein the structure is mainly either a regular or irregular matrix of void spaces.[33]

Figure 6 Scanning electron photomicrographs of expanded finger millet: (a) whole kernel; (b) surface of the kernel; (c) transverse section-opaque portion; and (d) transverse section-transparent portion.

CONCLUSIONS

The expanded finger millet with a near spherical shape contained two concentric spheres with a crisp and fragile structure. Some of its functional properties and the pasting profile reveal the presence of pregelatinized starch. The carbohydrate and lipid profiles of the product indicated that during high temperature and short time treatment, some portion of the starch undergoes thermal degradation and the proportion of monounsaturated fatty acid increases. The expanded millet is a new generation product and can be conveniently used in snacks, supplementary foods, health bars, and such other foods suitable for all age groups.

ACKNOWLEDGMENTS

The authors wish to thank Mr. Anbalagan for SEM photography. The financial support received from ICAR, New Delhi (AICSMIP) to carry out this work is also gratefully acknowledged.