Quality Improvement of Biscuits Using Some Different Protein Sources

INTRODUCTION

Malnutrition is one of the key health problems affecting children in Egypt. Malnutrition is usually caused by inadequate dietary intake qualitatively or quantitatively or both of them (Anonymous, 1995). Malnutrition is considered a common health problem in Egypt, which the children are the most vulnerable group of malnutrition(Motaza Rashed, 2002).

In the stages of children life, the amount and nutritional quality of protein are particularly important due to their essential function in physical and mental development. Protein is essential for life because it is a component of every cell and has diverse physiological functions (Nieman, 1990).

Stuffer(1983) mentioned that the nutritional value of snacks products is very low, on the other hand, Sai Manohar and Haridas Ras (1997)reported that the quality of biscuits depends on the quantity and quality of ingredients especially the flour. It was found that mixing tow or more different materials will help to solve the deficiency problem of cereals as low nutritional value by used legumes as food protein source (Pipes and Trahms, 1993).

Mung bean is considered as rich source of essential amino acids (El-Rify et al., 2000). Also, chickpeas are important source of vegetable protein contained adequate amounts of most essential amino acids for preschool children (Paredes-Lopez et al., 1991; Abd El-Akher et al., 1995 and Clement et al., 1998). Moreover, addition of small amount of milk protein leads to increase the nutritional value of the cereal products (Cooper et al., 1984).

The purpose of the present study is to produce biscuits supplemented with mung bean and chickpeas flours as protein sources. Also, study the chemical composition, the nutrative value and evaluate the sensory acceptability of fortified biscuits.

MATERIALS AND METHODS

Materials:

• ·         Wheat flour (72% extraction) was obtained from local market.
• ·         Mung bean and chickpeas were obtained from Agriculture Research Center, Giza, Egypt.
• ·         Dried skim milk was obtained from the National Research Center, Dokki, Giza, Egypt.
• ·         Yeast, shortening, salt, sodium bicarbonate were obtained from local market.

Methods:

         Preparation of mung bean and chickpeas flours:

Cleaned seeds of mung bean and chickpeas were soaked at ambient temperature in a 0.5% sodium bicarbonate solution (1 : 4, w/v) for 12 hours to eliminate undesirable beany flavor, the seeds were drained, washed with cold tap water and then blanched for 20 minutes to destroy trypsin inhibitor (Tonella et al., 1983) ground, dried at 50ºC and finally milled in order to pass through a 60 mesh sieve.

Biscuits making:

Biscuits were prepared included 100g. of ingredients with yeast, shortening, water, salt, malt and sodium bicarbonate by 23, 9.5, 30.8, 1.4,0.02 and 0.63g. respectively according to the method described by Dovaldk and William (1975). Different biscuits formulate were designed using a vary amounts of the ingredients showing in Table (1).

Table (1): Composition of biscuit samples.

Methods of analysis:

Moister, crude protein, crude fat, crude fiber and total ash were carried out according to methods in the A.O.A.C. (1995).

Total carbohydrates were calculated by difference, food energy was calculated by multiplying carbohydrates, fat and protein contents by 3.87, 8.79 and 4.27 K. cal/g., respectively, according to Radi and Arous (2000).

Amino acids were determined in the acid hydrolysis according to the method described by Pellet and Young (1980) using Backman Amino Acid Analyzer.

Essential amino acids were determined according to the method of Becker et al.,(1981). Tryptophane was determined calorimetrically according to Blouth et al., (1963).

Protein efficiency ratio (PER) was calculated by the following equation. PER= -1.816 +0.435 (Methionine) +0.780 (Leucine) +0.211 (Histidine) -0.944 (Tyrosine), according to Alsmeyer et al., (1974).

Biological value (BV) was calculated by the following equation. BV = 49.9 + 10.53 (PER), according to Mitchell and Block (1946). Chemical score of essential amino acids was calculated according to Bhanu et al., (1991).

Organoleptic Evaluation:

Biscuit samples were evaluated by ten panelists for odor, taste, shrinkage, crispiness, thickness, color and appearance according to the method described by Gerczyca and Zabic (1979). Organoleptic results were statistically analyzed according to Snedcor and Cochran (1980).

RESULTS AND DISCUSSION

Chemical composition on raw materials were shown in Table (2). It is clear from the results that the protein content of wheat flour was lower than that of the other ingredients. The highest amounts of protein was found in dried skim milk followed by mung bean and chickpeas flours (35.7, 31.7 and 21.83g./100g.) respectively as compared with wheat flour (12.8g./100g.).

As a results of high protein levels of mung bean flour and chickpeas flour, we can use this vegetable protein to fortified low protein cereal products, according to Miller (1967).

Table (2): Chemical composition of raw materials (g./100g.dry weight basis).

* Carbohydrates = 100 - (Moisture + protein + Fat + Fiber + Ash).

It could be observed that wheat flour had the highest amounts of carbohydrate (73.33%) was found in wheat flour meanwhile the lowest amounts (51.00%) was found in dried skim milk. On the other hand, the high ash level was found in dried skim milk (8.10%) followed by mung bean flour, chickpeas flour and wheat flour (2.73, 2.23 and 1.28%), respectively. The results revealed that the highest amounts of fiber was found in mung bean flour followed by chickpeas flour and wheat flour ranged from (5.50, 3.43 and 1.60%), respectively. The finding results were in agreement with those obtained by Paredes-Lopez et al. (1991), Mubarak (2000) and El-Rify et al. (2000).

Table (3) represented the chemical composition of different biscuit samples. The moisture content of the supplemented biscuits ranged between 2.96 to 3.01% and was higher comparing with the control (2.81%), these results may be due to the water retention capacity of skim milk and other ingredients according to (Erdogdu-Arnoczky et al., 1996). Generally, this low moisture content of all samples gave a very low susceptibility to microbial spoilage. These results are in agreement with those reported by Labuza and Contreras-Medellin (1981). As a result of adding dried skim milk, mung bean flour and chickpeas flour, the protein value was higher as compared with control sample. The highest amount of protein was in sample No.4 (123.6%) whereas samples No.6,2,5,3, and 1 had being 119.82, 116.30, 115.96, 110.81 and 108.92%, respectively comparing with control sample. These results are consistent with those reported by Cooper et al. (1984), Abd El-Akher et al. (1995), Clement et al. (1998) and El-Rify et al. (2000). Also, results noticed that total carbohydrates of biscuit samples indicated that a reversible trend in relation to the quantity of protein. The highest level of carbohydrate was in control sample (74.34 g. /100g.) while the lowest level was found in sample No.4 (94.17%) compared with control. On the other hand, the proximate composition of the biscuits provided a good caloric values i.e. 396.70 to 399.10 K.cal /l00g.sample for the 3 and 4 treatments as a results of adding chickpeas flour 5 and 10% with dried skim milk 5%, respectively. These results are in agreement with those reported by Johnson et al. (1985) and Baker (1997).

Table (3): Chemical composition of different biscuit samples (g./100g. dry

weight basis)

Essential amino acids composition, protein efficiency ratio and biological value of biscuit samples as compared with protein pattern were demonstrated in Table (4). It could be noticed that the concentration level of essential amino acids of biscuit samples also tyrosine and histedine were increased comparing with control. As compared with control, the percentage of total essential amino acids were raised (103.82 to 116.29%).

Table (4): Essential amino acids composition, protein efficiency ratio (PER) and biological value (BV) of the biscuit samples comparing with protein pattern

* Essential amino acids.

** Protein pattern of preschool children according to FAO/WHO (1985).

Comparison with FAO/WHO pattern (1985) indicated that the lowest level covered the requirements of total essential amino acids was in control sample (76.9%) which increased to (89.44%) in sample No.4 which contained (10% of mung bean flour and 5% of dried skim milk) followed by No.6,5,2,3 and No.1 (87.90, 86.91, 83.81, 82.37 and 79.89%) respectively.

 On the other hand, in sample No.4 which contained (10% of mung bean flour and 5% of dried skim milk), PER was increased to 111.20%, also BV was increased to 104.22% comparing with control. In general as a result of added mung bean flour, chickpeas flour and dried skim milk, the essential amino acids of biscuit samples were increased and the (PER) and (BV) were improved. These results are in accordance with those reported by Cooper et al. (1984); Clement et al. (1998); El-Rify et al. (2000) and Radi & El-Nahas (2004).

Chemical protein score and limiting amino acid of biscuit samples comparing with protein pattern were illustrated in Table (5). It is obvious that, supplementation of biscuit samples with mung bean flour, chickpeas flour and dried skim milk increased the chemical protein score about 125.90 to 182.94% as compared with control. Also, results indicated that, lysine was the limiting amino acid in all biscuit samples.

Table (5): Chemical protein score and limiting amino acid of

biscuit samples comparing with protein pattern.

* Protein pattern of preschool children according to FAO/WHO (1985).

Results given in Table (6) show mean values + SD of organoleptic evaluation of different biscuit samples. It could be noted that samples No. 4, 5 and 6 were significantly decreased for odor and shrinkage (P<0.05) comparing to the control. Whereas, the same samples were significantly increased (P<0.001) for taste and crispiness followed by samples No.2 and 3 (P<0.01). These results may be due to bicarbonate treatment during preparation of mung bean and chickpeas flours (Damir, 1992).

On the other hand, no significant differences were noticed among the samples for thickness. It is apparent from the data that the color was improved for samples 4,5 and 6 (P<0.01) comparing to the control sample. These results were according to Johnson et al. (1980).These results indicated that biscuit samples fortified with mung bean flour and chickpeas flour (10%) had the highest values for appearance which significantly increased (P<0.001) for samples No.4 and 5 followed by samples No.2,3 and 6 (P<0.01).

It can be concluded that, the samples were study can be arranged descending manner due to its nutritive value as the following:

-          The first: sample No.4 (85, 10 and 5% of wheat flour, mung bean flour and dried skim milk) respectively.

-          The second: sample No.6 (85, 5, 5 and 5% of wheat, mung bean chickpeas flours and dried skim milk) respectively.

-          The third: sample No.5 (85, 10 and 5% of wheat flour, chickpeas flour and dried skim milk) respectively.

-          The fourth: sample No. 2 (90,5 and 5% of wheat flour , mung bean flour and dried skim milk) respectively.

-          The fifth: sample No. 3 (90,5 and 5% of wheat flour , chickpeas flour and dried skim milk) respectively.

-          The sixth: sample No. 1 ( 95 and 5% of wheat flour and dried skim milk) respectively.

-          The seventh: the control sample1 ( 100% of wheat flour) .

-          Also, it is clear from the results that, 112 g. from the sample No.4 covered the daily requirements of total essential amino acids .

Generally, the addition of mung bean and chickpeas flours with wheat flour at different levels were considered the optimal for the preparation of biscuits. These results are in a good accordance with reported by Witting De Penna et al. (1987); El-Bahay et al. (1994) and Mubarak (2000).

Table (6): Chemical composition of different biscuit (g. /100g. dry weight basis)