Development of Pasta and Extrudates Enriched with Omega-3 Fatty Acid and Saponin

In this study, an attempt has been made to develop a pasta and extrudates enriched with omega 3 fatty acid and saponin. Flax seed ( Linum usitatissimum ), rich in omega 3 fatty acid, and vallarai ( Centella asiatica L), good source of antioxidant saponin were selected for this study. Experiments were carried out using both germinated and ungerminated flax seed powder in combination with vallarai. The pasta and extrudates made out of ungerminated flax seed were found to have greater amounts of antioxidant and iodine value compared to the products made using germinated flax seed. It was concluded that the pasta made with a composition of 10% vallarai and 20% ungerminated flax seed with maida as a base material and extrudates made of rice flour, 10% soy flour, 20% ungerminated flax seed powder and 10% vallarai were adjudged as the best samples based on the biochemical and sensory attributes.

i.e. alpha linolenic acid (ALA). The active ingredient of flaxseed (lignan, secoisolariciresinol diglucoside (SDG)) has significant antioxidant effects by inhibiting DNA scissions and lipid peroxidation (Kitts et al., 1999). The flax seed also has significant antiinflammatory effects (Cohen et al., 2005). The soluble fibre removes cholesterol from gastro intestinal tract and lowers bowel fermentation to short chain fatty acids that suppresses cholesterol production. Therefore, it is suggested that flax seed supplementation could be an excellent way to lower the risk of heart disease.
Bioactive compounds in plants are considered to be critical for human health. One such medicinal plant is Vallarai (Centella asiatica L.), which belongs to the family Apiaceae (Umbelliferae). This green leafy vegetable contains biochemical constituents such as asiaticoside, asiatic acid and madecassic acid, which serve as the active ingredients supporting the body's vitality (Narayana Das et al., 2003).
Keeping in view the importance of fortification of flax seed and vallarai with maida as a base material for pasta and with rice flour as a base material for extrudates, this study was conducted with an aim to incorporate omega-3 fatty acid (flax seed) and saponin (vallarai) in pasta and extruded products to make it highly nutritious.

Materials and Methods
Raw materials like maida, corn flour, soy flour and rice flour were procured from well established supermarket. The flours were sieved using ISS 40 sieve for the experiments. Fresh vallarai green leafy vegetable free from pests and diseases was procured from a progressive farmer to get consistent quality raw materials for the experiments. The bunches were carefully dehanded and washed in potable water to remove adhering soil, dirt etc, .and it was ground into a paste using mixer. Flax seed, free from dust, dirt and insects, was procured from a well established supermarket. The flax seeds were germinated, sun dried and ground for use in the experiments. The flour was sieved using ISS 100 sieve and incorporated for use in the experiments to increase its nutrient availability in the body.
The ingredients such as germinated and ungerminated flax seed powder, vallarai paste, salt, maida were used for making pasta using pasta making machine (M/s, LB ITALIA). The pasta was prepared with three levels of germinated and ungerminated flax seed powder namely, 15, 20 and 25% and three levels of vallarai namely, 5, 10 and 15% keeping maida as base material along with water (30%).
The optimum levels of flax seed and vallarai was used for further preparation of extruded products. A twin screw extruder (M/s, Basic Technology Private Limited, Kolkatta) was used for the production of extrudates. The raw ingredients such as germinated, ungerminated flax seed powder, vallarai paste, salt, rice flour, corn flour, soy flour were fed to produce extrudates under different combinations.

Cooking time
A sample of pasta was 10 g of cooked in 160 ml distilled water. The optimal cooking time was determined visually by pressing such strands between two plates for the starchy white core of the pasta to disappear (Zweifel et al., 2003 ).

Water uptakse
Water absorption in ml was calculated by relating the gain in weight between dry and cooked pasta.

Cooking volume
The difference in the volume of the pasta before and after cooking to a predetermined time was calculated using a measuring cylinder.

Expansion ratio
The diameter at different locations along the strand of an extrudate was measured and the expansion ratio was calculated by dividing the average diameter of the strand by the diameter of the die.
Expansion ratio = Diameter of a ring shaped extruded sample (mm) Diameter of the die outlet (mm)

Iodine value
The iodine value is a measure of the degree of unsaturation in oil. The reagents such as chloroform, hanus iodine solution, 15 % potassium iodide and 1% starch indicator were added to the sample. It was titrated against 0.1N sodium thiosulphate until yellow solution turned colourless. The iodine value of the sample was estimated using the following formula B = thiosulphate for blank, ml S = thiosulphate for sample, ml N = normality of thiosulphate solution

Antioxidant activity
The antioxidant Activity was determined using FRAP (Ferric Reducing Antioxidant Power) Assay. The reagents used were acetate buffer, TPTZ (10 mmol/l), ferric Chloride (20 mmol) [freshly prepared], FRAP (Ferric Reducing Antioxidant Power) working solution and ascorbic acid (1mM) stock standard. Aliquots of 0.2 to 1ml were pipetted out in test tubes. The volume was made up to 1 ml in each tube with water. Then 0.5ml FRAP reagent was added. After a period of 10 minutes the absorbance was measured at 593nm.

Moisture content
Moisture content was determined using vacuum oven method. The oven was run at a pressure of 25mm of Hg at 98-100°C for a period of 5 h (AOAC Method No. 925.09, 2000). The moisture content was determined using the following equation, Sample weight (g) x 100 ……… (2) Initial weight-Final weight, g Moisture content, % d.b. Final weight, g =

Sensory evaluation of pasta
Hedonic sensory evaluation was conducted by 16 trained panelists consisting of food science and food engineering faculty members. The panelists were asked to evaluate the hedonicity of appearance, colour, flavour, texture and overall acceptability of the pasta on a 9-point hedonic scale (ISI specification-IS 6272: 1991) ranging from 1 (most disliked) to 9 (most liked).

Statistical analysis
Data analysis was performed using AGRESS SOFTWARE (Factorial Completely Randomized Design) to optimize the combination of ingredients and to evaluate the quality attributes.

Effect of germination on cooking qualities of pasta
Cooking time Table 1 represents the effect of germination of flax seed on cooking qualities of pasta. It was found that there was a reduction in the cooking time with germination of flax seed. The combination of 15% of vallarai and 25% of germinated/ungerminated flax seed powder recorded the highest cooking time compared to the product with the combination of 5% of vallarai and 15% of germinated/ungerminated flax seed powder. Statistically it was found that the combination of 5-10% vallarai and 15-25% flax seed powder were on par with each other and gave best results with respect to cooking time. This is due to the fact that during the process of germination, the cells are liberated and swell by absorbing water thus enhances cooking. Similar results have been reported by Kordylas (1990).

Water uptake
The effect of germination on water uptake of pasta made using germinated and ungerminated flax seed powder is shown in Table 1. The pasta made of germinated flax seed powder exhibited maximum water uptake compared to the one made with ungerminated flax seed powder. Similar trend was reported by Kordylas (1990). The combination of 15% vallarai + 20% flax seed powder and 10% vallarai+25% flax seed powder were found to be statistically on par with each other with respect to maximum water uptake.

Cooking volume
The effect of germination on cooking volume of pasta was represented in Table 1. It was observed that the sample with the combination of 5% of vallarai and 15% of flax seed recorded the highest cooking volume. The cooking volume was lower in the samples having combination of 15%, 20% and 25% of germinated flax seed with 10% vallarai. This may be owing to the decrease in the water uptake by the samples.

Expansion ratio
It was found from the Table 3 that the sample made out of rice flour, 10% corn flour, 20% germinated flax seed and 10% vallarai attained the maximum expansion ratio of 1.83 and samples made out of soy flour had the minimum expansion ratio of 1.5. This may be due to the higher starch content of the corn based extrudates and also the corn extrudates were found to have larger and smoother air cells than extrudates with high protein content. The same phenomenon was reported by Atienzo-Lazos et al., (2011). Also it was observed that the sample prepared using rice flour, 10% corn flour, 20% ungerminated flax seed and 10% vallarai was found to attain the maximum expansion ratio of 2.2.and the extrudates prepared using rice flour, 10% soy flour, 20% ungerminated flax seed and 10% vallarai and rice flour, 15% soy flour, 20% ungerminated flax seed and 10% vallarai had the minimum expansion ratio of 1.6.

Iodine and antioxidant value
The flax seed powder contained an iodine value of 120.4 and an antioxidant value of 195 μg/g. While being incorporated in the ingredients for making pasta, it was found that there was a loss of 20 to 40% and 30 to 60% in antioxidant value and iodine value, respectively (Table 2). It was observed that the sample containing 5% vallarai and 15% germinated flax seed powder exhibited a minimum loss of 25.9% in iodine value whereas the maximum loss of 39.77% was observed in the sample having 15% vallarai and 25% germinated flax seed powder. The minimum loss of 30.76% in antioxidant value was observed in the sample with 15% vallarai and 20% germinated flax seed powder and a maximum loss of 57.6% was noticed in the sample containing 5% vallarai and 15% germinated flax seed powder. The ungerminated flax seed powder contained an iodine value of 121.97. During incorporation the loss ranged from 5 to 25% and 25 to 50% in iodine value and antioxidant value respectively. It was observed from Table 2 that the sample having a combination of 15% vallarai and 20% germinated flax seed powder, the per cent loss in iodine value was minimum and it was maximum in 5% vallarai and 20% ungerminated flax seed powder sample. The minimum loss of antioxidant value was observed as 25.6% in the sample having 10% vallarai and 20% ungerminated flax seed powder and a maximum loss of 48.6 % in the sample having 5% vallarai and 15% ungerminated flax seed powder.
Statistically, the pasta prepared using ungerminated flax seed powder has the maximum retention of antioxidant and iodine value and found to the best in comparison with pasta prepared using germinated flax seed powder. It was also observed that the pasta made with different formulation using flax seed powder and vallarai was found to have a significant effect (P<0.01) on the biochemical qualities of the pasta. The pasta with a formulation of 10% vallarai, 20%flax seed powder and 15% vallarai and 15% flax seed powder with maida as a base material were found to be on par and the best formulation with respect to biochemical qualities.
The loss may be due to the heat generated by the compression of the ingredients in the pasta making machine. Further, it was found that pasta produced using ungerminated flax seed powder had the best retention of biochemical qualities compared to the pasta made out of germinated flax seed powder. This may be due to the breakdown of fatty acids upon germination, which would have resulted in the decreased iodine and antioxidant value of the product.
From Table 3, it can be observed that the extrudate made of rice flour, 10% soy flour, 20%  ungerminated flax seed and 10% vallarai was found to have the minimum loss of iodine value (18.08%) when compared to the extrudate made of rice flour, 20% corn flour, 20% un germinated flax seed and 10% vallarai which has maximum loss of 40.96%. It was inferred that the corn based product had the maximum loss in iodine value. This may be due to the high starch content in the corn flour.
Statistically, germination was found to have no significant effect upon the antioxidant value, whereas the extrudate prepared using ungerminated flax seed powder resulted in higher iodine value. The lower iodine value for the germinated flax seed powder compared to ungerminated flax seed powder may be due to the breakdown of the fatty acids during germination. It was also observed that the extrudate made with different formulation using flax seed powder and vallarai was found to have a significant effect (P<0.01) on the biochemical qualities of the extrudate. The extrudate made of rice flour, 10% soy flour, 10% vallarai paste and 20% ungerminated flax seed powder was found to be statistically the best formulation with respect to the retention of the biochemical qualities of the extrudates.

Moisture content
The moisture content of the pasta was found to be ranging from 10% to 11.2% (d.b.).

Sensory analysis
The sensory evaluation was conducted for the pasta and extrudate using a trained panel. Based on the evaluation, the pasta with a formulation of 10% vallarai and 20% flax seed powder and the extrudate with a formulation of rice flour, 10% soy flour, 20% ungerminated flax seed powder and 10% vallarai was adjudged as the best formulation in terms of colour, appearance, flavor, texture, taste and overall acceptability.

Conclusion
It is concluded that the pasta made with a combination of 10% vallarai, 20% flax seed powder with maida as the base material is the best in terms of bio chemical, cooking qualities and sensory evaluation. It is also concluded that the germination of flax seed has no significant changes in the quality attributes of pasta. The extrudate with a formulation of rice flour, 10% corn flour, 20% flax seed and 10% vallarai is estimated to have the maximum expansion ratio. Combining the above analysis results it is determined that the sample made of rice flour, 10% soy flour, 20% ungerminated flax seed powder and 10% vallarai is the best among the extruded samples. The product fortified with ungerminated flax seed powder and vallarai is found to be acceptable, containing the highest amount of omega 3 fatty acids and saponins.