Wheat bulgur, tomato, potato, carrot, black pepper, coriander, cumin, salt, onion and garlic powder were purchased from local market, Giza, Egypt. Mung bean Varity (Giza 1) was obtained from legume research department, Field Crops Research Institute, Agricultural Research Center.

Mung bean was sorted and washed with tap water, then soaked for 12 hr. at room temperature. The soaked mung bean was placed in wet cloth and left for germination 48 hr. at room temperature Yasmin et al. [13].

Unsoaked, soaked and germinated mung bean were cooked in boiling water at 100˚C for 45 min for unsoaked and 30 min for soaked and germinated mung bean then washed in cold water, then dried with hot air flow using air oven at 65˚C in the first four hours and then reduced to 50˚C till completely drying until constant weight. The dried samples were ground into powder using a grinder and sieved (250 micron) for identical size particles, then packed in polyethylene bags and kept in deep freezer for till using.

Potato, tomato and carrot were sorted and washed, then the potato and carrot were peeled and sliced in cubic form and blanched in hot water at 100˚C for 10 - 15 min, then the tomato was peeled. Wheat bulgur was soaked for 6 hr. then cooking in boiling water at 100˚C for 30 min. All ingredients washed in cold water after boiling process, then dried with hot air flow using air oven at 65˚C in the first four hours and then reduced to 50˚C till completely drying to constant weight. The dried samples were ground into powder using a grinder and sieved (250 micron) for identical size particles, then packed in polyethylene bags and kept in deep freezer for till using.

All ingredients were spiced with onion and garlic powders, coriander, black pepper, cumin and salt to get three formulations of instant porridge, B1 had 30% unsoaked mung bean, B2 had 30% soaked mung bean and B3 contained 30% of the germinated mung bean as shown in Table 1. The obtained formulas were packed in polyethylene bags and kept in deep freezer for till using.

1) Chemical composition of dried instant porridge formulas

Moisture, crude protein, fat, crude fiber and ash contents were determined according to AOAC [14]. Total carbohydrates were calculated by difference.

2) Calories value

Calories value was calculated by James [15] as follows:

calories value ( Kca / 100 g ) = 4 ( protein ) + 4 ( carbohydrate ) + 9 ( fat )

3) Amylose content

Amylose content was determined by the colorimetric method according to Kumari et al. [16].

4) Determination of amino acids profile

Amino acids profile were determined using an Amino Acid Analyzer (Biochrom 30) using the instruction manual according to AOAC [14].

5) Chemical score (CS)

Chemical score was calculated according to FAO/WHO [17].

Chemical score ( % ) = ( EAA of crude protein / EAA of FAO / WHO ) × 100

6) Biological value (B.V)

Biological value was positively correlated with the lysine concentration. It calculated according to Eggam et al. [18] as follows:

Biological value ( % ) = 39.55 + 8.89 × lysine ( g / 100 gprotein ) .

7) Minerals content

Minerals content were determined by using the flame photometer (Galien kamp, FGA 330, England) and Perkin Elmer Atomic Absorption Spectrophotometer. (Model 80, England) as described in AOAC [14].

8) Determination of phytic acid content

The phytic acid content was determined according to Park et al. [19].

9) Tannins content

Tannin was determined by using the Vanillin-HCl method modified by Price et al. [20].

1) Water activity (a_w)

The water activity was measured using Rotronic Hygro lab CH-8303, Switzerland as mentioned by Cadden [21].

2) Color Measurement

External color was measured according to the method outlined by McGurie [22] using a hand-held Chromameter (model CR-400, Konica Minolta, Japan).

3) Water absorption index (WAI) and water solubility index (WSI)

WAI and WSI were determined as described by Silvia et al. [23]. One gram of dried instant porridge samples were suspended with 10 ml distilled water at room temperature for 30 minutes, gently stirred during this period and then centrifuge at 3000 rpm for 15 minutes. The supernatant liquid was poured carefully in to evaporating dish of known weight and dried at 110˚C to constant weight. The weight of the remaining gel was taken as WAI.

WAI   g / g = weight of remaining gel Weight of dry porridge sample

The amount of dried solids, recovered by evaporating the supernatant and expressed as percentage of dry solids was taken as WSI:

WSI% = weight of dried solid in supernatan Weight of dry porridge sample × 100

4) Swelling power (SP)

SP determined with the method described by Oladele and Aina [24]. One gram of dried instant porridge samples were mixed with 10 ml distilled water in a centrifuge tube of known weight and heated at 90˚C for 30 min. This was continually shaken during the heating period. After heating, the suspension was centrifuged at 1000 rpm for 15 min. The supernatant was decanted and the weight of the porridge taken. The swelling power was calculated as:

SP   g / g = weight of the swollen porridge sample weight of dry porridge sample

5) Viscosity

The dried instant porridge formulas were placed in a water bath to maintain at 40˚C (the temperature at which viscosity measurement was taken). Brookfield viscometer DV-III ultra was used to measure the porridge viscosity (in centipoises, cps) using spindle at a shear rate of 50 rpm in 30 seconds. Brookfield Viscometer for all porridge formulas were measured according to Tizazu et al. [25].

RR was performed according to Huang et al. [26]. Two gram of dried instant porridge formulas were rehydrated in (20 ml) distilled water in a water bath at constant temperature and was agitated at constant speed. The samples were taken from the bath after 10 minutes and weight.

The rehydration ratio was defined as the ratio of weight of rehydrated samples to the dry weight of the samples. The rehydration ratio was calculated using weight of samples before and after rehydration as follows:

RR   ratio = W 2 − W 1 W 1

W1 = the initial weight of the porridge samples;

W2 = the final weight of the porridge samples.

The rehydrated instant porridge formulas were prepared according to Ocheme and Chinma [27]. 20 g of dried porridge was mixed with 100 ml of cold water to form slurry and stirred continuously for 10 min until the mixed completely converted into soft cooked porridge formed, at 100˚C to 120˚C. Then it was removed from the heater and allowed to cool to 30˚C to make ready to serve.

Sensory acceptability in terms of color, odor, taste and overall acceptability of porridge. The evaluation was carried out by ten panelists using hedonic scales in order to assess the acceptability of each product 1 to 9 (where 1 = very much disliked, 9 = very much liked,) according to Ocheme and Chinma [27].

The obtained data were exposed to analysis of variance (ANOVA). Duncan is multiple range tests at (P ≤ 0.05) level was used to compare between means values according to Waller and Duncan [28].

Data in Table 2 showed that B1 formula had the lowest value of carbohydrate and amylose content, while B2 had the lowest value of ash and crude fiber. Our results agree with Wang et al. [29] who reported that the ash content after soaking was reduced. On the other hand the crude protein slightly decreased in B2 than B1, this might be due to leaching of soluble protein into soaking water [30]. While B3 was significantly decreased in fat, protein and calories value compared to B1 and B2, these reduction in protein and fat during the germination process may be due to the increased activity of the protease enzyme that breaks down the protein for use in growth sprouts [31] [32], the reduction in fat may be due to the oxidation of fats to carbon dioxide and water to produce the energy needed for germination [33] [34].

B1: porridge formula + unsoaked mung bean, B2: porridge formula + soaked mung bean, B3:porridge formula + germinated mung bean, Values are mean of three replicates ± SD, means with different letters at the same column are significantly different at P ≤ 0.05.

The essential amino acids are necessary for tissue protection and can’t be synthesized by the body and an important index of protein quality in food product. Results presented in Table 3 showed that B3 formula had the lowest level in total essential and non-essential amino acids (30.90 and 50.29 g/100g protein, respectively) compared to B1 and B2, may be due to the consumption of amino acids in the formation of new tissues during growth.

Furthermore, B2 formula had the highest level of the total non-essential amino acids and total aromatic amino acids (Phenylalanine and Tyrosine) compared to the other formulas, may be due to the soaking process which caused an increase in the total non-essential amino acids than total essential amino acids, also the total aromatic amino acid was the highest than the other essential amino acids [30].

On the other hand the data in the same Table 3. Indicated that the all formulas were high in the total non-essential amino acids than the total essential amino acids as well as the total Phenylalanine and Tyrosine were high compared to the other essential amino acids.

Chemical score is a method for assessing the quality of a dietary protein in a diet, measured by the ratio of a gram of the limiting amino acid in a diet for the same amount of the identical amino acid in a reference diet multiplied in 100. From the same Table 3 observed that the chemical score of aromatic essential amino acids (phenylalanine and tyrosine) was the highest value compared to the other essential amino acids in all formulas.

The limiting amino acids of all formulas were lysine, may be due to contain the lowest of chemical score, where the limiting amino acid is known as the acid that had a low protein [35]. The reduction in lysine is due to the processing methods as soaking, cooking and germination [36].

The biological value described how well the body absorbs protein and measure the percentage of protein actually utilized in human body [37]. The results in Table 3 showed that B2 formula was the highest in the biological values 83.19% compared to the other formulas, may be due to contain high lysine content (4.91 g/100g protein), where the high lysine content was associated with an increase of the biological value [38].

B1: porridge formula + unsoaked mung bean, B2: porridge formula + soaked mung bean, B3: porridge formula + germinated mung bean, EAA = essential amino acids, ND = not detected, B.V = biological value, AAA = aromatic amino acids, SAA = sulfur amino acids, FAO/WHO (2007).

Minerals are essential chemical elements that play a role in glucose homeostasis, the transmission of nerve impulses and enzyme cofactors in the body. Macro minerals are needed in large amounts, while trace minerals are needed in very small amounts. The minerals content of instant porridge formulas were presented in Table 4. B1 formula recorded the lowest content of minerals except K

B1: porridge formula + unsoaked mung bean, B2: porridge formula + soaked mung bean, B3:porridge formula + germinated mung bean, Values are mean of three replicates ± SD, means with different letters at the same column are significantly different at P ≤ 0.05.

which recorded high (1540.41 mg/100g). Macro and trace minerals significantly increased in B3 formula except K that significantly decreased (1449.71 mg/100g) compared to the other formulas, this reduction may be due to soaking and germination.

The rising of minerals as a result to decrease anti-nutritional factors leached out during the soaking process and degraded during germination. Processing methods like, soaking, germination and cooking lead to decrease that the anti-nutritional factors and increase minerals bioavailability (Ca, Cu, Mn and Zn), nutritive value and enhance the digestibility [8] [39].

Anti-nutritional factors, such as phytic acid was has a negative charged which bond with positively charged divalent minerals ions making them unavailable for absorption and tannin are chemical compounds that affect digestion, bioavailability and limit the full benefit of nutrients in food.

The results in Figure 1 and Figure 2 illustrated that B3 formula had the highest reduction in phytic acid and tannin content (0.40% and 0.09%), respectively followed by B2 formula (0.63% and 0.21%), respectively. The reduction of Polyphenols (tannin) and phytic acid could be attribute to leach them with soaking water, also due to the increasing activity of phytase which responsible for the hydrolysis of phytic acid during traditional processing techniques such as soaking and germination [8] [36] [40] [41].

The rehydration ratio indicates the ability of dried materials to absorb water and to hold soluble solids inside the dried material. Also, it is a considered an important characteristic of many products, which later preparation for consumption [57] and used it as a quality characteristic of the dried product [58].

The rehydration ratio of the dried porridge formulas increased significantly in B1 formula compared to the other formulas shown in Figure 3, this may be attributed to the limited initial moisture [59]. Also, due to lower water activity and water content [1].

Sensory Evaluation is a good way to solve problems associated with food acceptance. The end product should be free from unacceptable taste and odor [60].

Sensory evaluation of the rehydrated instant porridge according to color, taste, odor and overall acceptability were illustrated in Table 9. There were a significant increase in color, taste and overall acceptability in B2 formula compared to the other formulas, the lighter color made them more acceptable, where consumers are used to this color in the food [27].

B1: porridge formula + unsoaked mung bean, B2: porridge formula + soaked mung bean, B3: porridge formula + germinated mung bean, Values are mean of ten replicates ± SD, means with different letters at the same column are significantly different at P ≤ 0.05.