Formula optimization of instant noodles - INFLIBNETshodhganga.inflibnet.ac.in/bitstream/10603/85473/12/12_chapter 4.pdf · Formula optimization of instant noodles . 58 fried noodles

Formula optimization of instant noodles

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CHAPTER 4

FORMULA OPTIMIZATION OF INSTANT NOODLES

4.1 Abstract

The effect of major ingredients including water (30-35%), alkaline salt (0.1-0.3%), guar gum

(0.2-0.6%) and salt (1-2%) on the quality of instant noodles has been studied. Response

surface methodology (RSM) tool was used to assess factor interactions and models taking

into account five response variables (i.e. oil uptake, cooked weight, cooking loss, hardness

and overall acceptability) for instant fried noodles. Higher addition of water was found to be

positively associated with oil uptake and cooked weight while negatively affected the cooking

loss, textural attributes and overall acceptability of noodles. Guar gum up to a level of 0.3%

was found efficient in improving the noodle quality. Alkaline salt were effective in improving

firmness, cooking quality and overall acceptability of noodles besides reducing the oil uptake.

The optimum level of the ingredients i.e. water, alkaline salt, guar gum and salt were

observed to be 30.97, 0.23, 0.28 and 1.54% respectively while attempting to minimize the oil

uptake and retain good noodle quality attributes. The results suggested that even varying the

formulation can be effective in controlling the quality of instant noodles especially oil uptake

during frying.

4.2 Introduction

Instant noodles represent a fast growing product with expanding demands in Asian countries

(WINA 2011; Yu and Ngadi 2004) due to their characteristics such as convenience, ease of

production, widely acceptable taste, texture and affordable price. Noodle quality apart from

flavourings and seasonings plays an important role in determining the acceptability of the

product, and is generally assessed in terms of colour, appearance, cooking quality, textural

attributes and sensory characteristics (Hou 2001). Ingredients are one of the important

determinants of final quality of instant noodles. The main ingredients for instant noodles are

wheat flour, salt or kansui (alkaline salt mixture of sodium carbonate and potassium

carbonate) and water (Kim 1996b). Other ingredients like starch, gums, emulsifiers,


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stabilizers, antioxidants, colouring and flavouring agents are often added to improve the

texture, eating quality and shelf life of instant noodles (Hou 2001).

The water absorption level generally used for noodle processing is about 30-38%

based on flour weight. Water absorption level influences the amount of work required during

sheeting as well as colour of the noodles. Insufficient water leads to the formation of non-

cohesive stiff dough thereby resulting in less extensible noodle sheet while too much water

causes dough stickiness creating handling problems during noodle processing (Hatcher et al.

1999). Textural characteristics have been observed to be negatively associated with

increasing water absorption in oriental noodles (Hatcher et al. 1999; Park and Baik 2002;

Edwards et al. 1996). The amount of salt added in noodles is usually 1–3% of flour weight.

Salt has been found to have a strengthening or tightening effect on the gluten proteins and

also improves and enhances the taste as well as flavour of noodles. The most commonly used

alkaline salts in instant noodles are sodium and potassium carbonates. However, other

alkaline reagents such as sodium hydroxide and bicarbonates may also be used. The type of

alkaline salt used has also been associated with quality of noodles (Hatcher et al. 2008c).

Addition rate of alkaline salts in instant noodle is 0.1 to 0.3% as a quality improver. At an

alkaline pH, dough characteristics are influenced including the behaviour of the gluten

proteins thus, resulting in tougher, tighter, and less extensible dough (Ong et al. 2010; Shiau

and Yeh 2001; Moss et al. 1986). Hydrocolloids have been viewed as multifunctional

ingredients that provide flexibility, act as fat replacers and water binders, improve rehydration

characteristics of noodles during cooking, modify texture and enhances the overall mouth-feel

of finished product.

While extensive research has been reported and focused on the effect of ingredients in

relation to yellow alkaline noodles, dried noodles, and white salted noodles but there are

relatively few studies that concerned instant noodles (Moss et al. 1987; Yu and Ngadi 2004,

2006). Recently, some researchers have focused on the studies related to instant noodle

quality. Wu et al. (2006) reported the effects of wheat flour composition, protein and starch

quality characteristics on oil content of steamed-and-fried instant noodles. Some other

researchers have also studied the textural and other quality properties of noodles (Park and

Baik 2004a; Park and Baik 2002). The aim of this study has been to investigate the impact of

varying the levels of major ingredients i.e. water, alkaline salt, guar gum and salt (NaCl) on

the final attributes (oil uptake, texture, cooking quality and overall acceptability) of instant-


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fried noodles. Response surface methodology was used to evaluate and determine the

optimum level of these ingredients.

4.3 Flour Analysis

The commercial flour analysis (Table 4.1) revealed that flour used for preparation of instant

noodles was of intermediate gluten strength as indicated by the SDS sedimentation volume,

protein content, gluten content, gluten index, C2, dough development time and stability (Fig.

4.1). The falling number was also observed to be higher indicating that flour was obtained

from sound grains free from sprout damage which has been further justified by a lower

difference between the C3 and C4 values. Ash content of 0.58% shows that flour extraction

rate was apt for noodle preparation with lower contamination of bran. Chemical as well as

rheological parameters support that the flour was suitable for instant noodle preparation.

Table 4.1 Characteristics of flour used

Flour Characteristics Values ± S.D

Moisture (%) 14.5 ± 0.10 Protein (%) 10.9 ± 0.20 Ash (%) 0.58 ± 0.02 Falling No. (sec.) 713.0 ± 5.00 SDS Sedimentation volume (ml) 41.0 ± 0.50 Gluten content (% dry gluten) 9.2 ± 0.30 Gluten Index 79.8 ± 0.50 Water Absorption (%) 58.5 ± 0.10 Development time (min) 4.0 ± 0.10 Stability (min) 4.0 ± 0.10 Softening (FU) 76.0 ± 2.00 C1 (Nm) 1.11 ± 0.01 C2 (Nm) 0.49 ± 0.01 C3 (Nm) 1.79 ± 0.01 C4 (Nm) 1.75 ± 0.01 C5 (Nm) 3.02 ± 0.02

4.4 Model Fitness

The experimental design sheet and response values obtained have been shown in Table 4.2.

To evaluate the fitness of model, F-values were determined (Table 4.3). The F-values for

models of oil uptake, cooked weight, cooking loss, hardness and overall acceptability (25.09,

33.29, 21.88, 21.17 and 23.09 respectively) were found to be highly significant (p<0.001). On

the other hand, the lack of fit for all the models was found to be non-significant even at the


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95% level suggesting that the selected models adequately represented the data for responses

studied. Backward regression was used to eliminate the insignificant (p>0.1) model terms and

derive the prediction equations for different responses studied (Table 4.4).

Fig. 4.1 Mixolab profile of the wheat flour

4.5 Effect of Ingredients on Oil Uptake of Instant Noodles

Frying of instant noodles results in removal of water from the strands imparting porous

structure and unique flavour due to fat/oil. However, higher oil uptake during the frying

process is undesirable due to potential health concerns and an increase in operating cost. A

quadratic model (RP

2P= 0.962) was obtained for oil uptake with A, B, C, AB, AP

2P, BP

2P,P

PCP

2P and

DP

2 Pbeing the significant model terms. It was observed that water absorption, alkaline salt and

guar gum are the main factors which significantly influence the oil uptake in instant noodles

(Table 4.3). The variation in oil uptake with water absorption and alkaline salt is shown in

Fig. 4.2a. As evident from the response surface graph, the oil uptake decreased steeply with

the incorporation of alkaline salt as well as water. However, it can be noted that increase in

oil uptake was more pronounced at higher levels of water absorption than alkaline salt.


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Similar observations for effect of water addition on oil uptake were reported by Yu & Ngadi

(2004).

Table 4.2 Experimental design for varying formula ingredients and response values obtained

S. No. A B C D OU CW CL HD OA 1 32.5 0.2 0.4 1.5 16.47 202.72 10.9 31.02 75 2 30 0.2 0.2 1.5 18.23 197.6 9.8 47.5 77 3 32.5 0.3 0.2 1.5 19.22 206 9 42.39 77 4 35 0.2 0.4 1 20.28 217.32 12.4 29.43 55 5 35 0.2 0.2 1.5 19.03 213.35 11.4 36.64 70 6 30 0.1 0.4 1.5 20.36 199.98 11.8 42.7 62 7 35 0.2 0.4 2 20.24 218.76 12 35.94 60 8 32.5 0.1 0.6 1.5 20.48 218.32 13.2 32.69 60 9 30 0.3 0.4 1.5 17.43 198.48 9.4 40.96 74 10 31.5 0.2 0.6 1.5 18.12 213.63 11 40.32 80 11 32.5 0.2 0.2 1 19.26 206.72 11.8 35.98 85 12 35 0.3 0.4 1.5 20.1 214.13 11.2 34.8 65 13 32.5 0.1 0.2 1.5 19.47 213.94 12.2 30.34 79 14 32.5 0.1 0.4 1 20.31 218.16 12.4 30.56 65 15 31 0.2 0.4 1 19.18 205.99 10.2 36.7 72 16 32.5 0.2 0.2 2 18.78 206.01 11.4 38.12 80 17 32.5 0.2 0.6 1 19.65 212.13 11.9 34.89 75 18 32.5 0.3 0.6 1.5 18.76 204.59 11 37.78 82 19 32.5 0.3 0.4 2 19.11 203 8.9 39.5 74 20 32.5 0.1 0.4 2 20.35 208.27 10.8 34.56 73 21 35 0.1 0.4 1.5 19.33 220.31 12.6 24.7 50 22 32.5 0.2 0.4 1.5 16.76 207.16 10.6 32.13 70 23 32.5 0.3 0.4 1 20.19 207.36 10.2 36.35 80 24 35 0.2 0.6 1.5 20.65 223.93 13 33.67 55 25 32.5 0.2 0.4 1.5 16.23 211.52 11.1 33.22 75 26 32.5 0.2 0.4 1.5 16.12 210.82 11.3 31.9 73 27 32.5 0.2 0.6 2 19.73 207.86 10.6 39.21 80 28 30 0.2 0.4 2 19.74 195.13 10.4 46.9 67 29 32.5 0.2 0.4 1.5 16.8 210.98 10.8 32.89 72

A= Water absorption, B=Alkaline salt, C=Guar gum, D=Salt, OU= Oil Uptake (% o.d.b), CW= Cooked Weight

(g/100g), CL= Cooking Loss (%), HD= Hardness (N) and OA= Overall Acceptability Score

Lower water content in the formulation results in crumbly and less cohesive dough

consequently forming noodles with rough surface which is responsible for higher oil uptake.

Saguy et al. (1998) has also mentioned that surface roughness increases the oil uptake as it

impairs oil drainage as well as increases overall surface area. A slightly higher water addition

will favour the formation of gluten network and contribute to increased starch gelatinization


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which may be responsible for the reduced oil uptake but much higher water content will result

in increased moisture content in noodles which need to be removed by frying and eventually

get replaced by oil.

Table 4.3 Analysis of variance for different response models

SourceP

a Oil uptake Cooked weight

Cooking loss

Hardness Overall acceptability

Model fitted Quadratic Linear Linear Quadratic Quadratic F- value Model 25.09*** 33.29*** 21.88*** 21.17*** 23.09*** A 12.35** 94.69*** 26.01*** 145.90*** 51.70*** B 16.91** 18.71*** 48.17*** 45.95*** 50.27*** C 9.45** 8.90** 5.69* 0.72 NS 17.66*** D 1.50 NS 5.66* 5.39* 21.24*** 0.27 NS AB 23.05*** - - 14.72** 0.34 NS AC 1.24 NS - - 0.58 NS 5.69* AD 0.002 NS - - 0.41 NS 2.22 NS BC 3.64 NS - - 5.09* 21.88*** BD 2.11 NS - - 0.08 NS 7.45* CD 0.53 NS - - 0.50 NS 3.80 NS AP

2 69.91*** - - 42.47*** 66.88*** BP

2 111.10*** - - 0.005 NS 3.61NS CP

2 61.97*** - - 36.36*** 26.20*** DP

2 Lack of Fit

153.53*** 1.83 NS

- 0.59 NS

- 4.83 NS

10.76** 4.05 NS

0.79 NS 1.65 NS

RP

2 0.962 0.847 0.785 0.955 0.959 Adjusted RP

2 0.923 0.822 0.750 0.910 0.917 Predicted RP

2 0.8030 0.783 0.671 0.743 0.805

*significant at p<0.05; **significant at p<0.01; ***significant at p<0.001; NS- not significant

P

aP A= Water absorption, B=Alkaline salt, C=Guar gum, D=Salt

In contrast, alkaline salt increases the water absorption and increases the proportion of

solid like behaviour of dough (Shiau and Yeh 2001) contributing to lower oil uptake.

Bouchon and Pyle (2004) also reported that a stronger and more elastic network can result in

a less permeable outer layer that may serve as an effective barrier against absorption of oil. It

can be depicted from Fig. 4.2b that incorporation of guar gum up to a level of 0.3% decreased

the oil uptake, while higher levels enhanced the oil uptake and were not desirable. Guar gum

has previously also been stated to reduce the oil uptake in instant noodles due to its ability to

bind water (Yu and Ngadi 2004). In addition, present results also indicated that higher guar

gum incorporation at lower alkaline salt content corresponds to a noticeable increase in the oil

uptake of noodles and thus not favourable.


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Fig. 4.2 Effect of (a) alkaline salt and water absorption (b) guar gum and alkaline salt

on oil uptake of instant noodles

4.6 Effect of Ingredients on Cooking Quality of Instant Noodles

A linear model suggested for cooked weight of instant noodles was significant at p<0.001

(RP

2P= 0.847). All the linear terms for water absorption, alkaline salt, guar gum and salt were

highly significant (Table 4.3). Water absorption and guar gum positively influenced cooked

weight while alkaline salt and salt (NaCl) negatively affected the cooked weight of noodles

(Table 4.4). Guar gum being a hydrocolloid favoured increase in cooked weight during

cooking. Similar findings for guar gum and water addition were reported by Yu and Ngadi

(2004). Fig. 4.3a depicts a decrease in cooked weight with addition of alkaline salt, whereas a

reverse trend was observed with increase in water absorption in the formulation of instant

noodles.

Linear model for cooking loss was significant at p<0.001 (RP

2P= 0.785) with water

absorption and alkaline salt as significant linear terms at p<0.001, while linear terms for guar

gum and salt were significant at p<0.05 (Table 4.3). Cooking loss reflects the surface

characteristics of cooked noodles. Higher cooking loss is associated with poor noodle surface

which hampers the appearance as well acceptability of noodles. Salt slightly reduced the

cooking loss while guar gum increased the same (Fig. 4.3b). Guar gum competes with the

(a) (b)


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protein for water due to its hydrophilic property, thus, weakening the protein network and

also reduces the starch paste viscosity on gelatinization thereby leading to higher cooking

loss.

Table 4.4 Predicted equation for different responses

Predicted equation for the responses in terms of coded factors P

a RP

2

Oil Uptake = 16.50 + 0.41 A − 0.46 B + 0.37 C − 0.14 D + 0.93 AB − 0.37 BC + 1.46 A2 + 1.57 B2 + 1.23 C2 + 1.88 D2

0.951

Cooked Weight = 209.14 + 9.13 A − 3.78 B + 2.61 C − 2.08 D 0.847 Cooking Loss = 11.12 + 0.87 A − 1.11 B + 0.38 C − 0.37 D 0.785 Hardness = 32.33 − 5.94 A + 3.02 B − 0.44 C + 2.10 D + 2.96 AB − 1.74 BC +4.431406 A2 + 3.706634 C2 + 1.996015 D2

0.949

Overall Acceptability = 73.64 − 5.80 A + 5.25 B − 3.22 C + 0.49 D − 3.50 AC + 6.00 BC −3.50 BD + 2.50 CD − 9.72 A2 − 2.00 B2 + 5.05 C2

0.950

P

aP A= Water absorption, B=Alkaline salt, C=Guar gum, D=Salt

Fig. 4.3 Response surface plot for the effect of (a) water absorption and alkaline salt on

cooked weight (b) salt and guar gum on the cooking loss of cooked instant noodles

It was also observed that cooked noodles with higher added water and guar gum had a

higher cooked weight due to more rehydration during cooking, poor cooked noodle surface as

well as higher cooking loss. Whereas, incorporation of salt and alkaline salt made the dough

stronger/firmer and elastic, thus, contributing to the reduction in cooked weight and cooking

loss. Choy et al. (2010) have also reported that a stronger and tighter protein network between

(b) (a)


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starch granules limits the excessive water uptake during cooking thereby decreasing the

cooked weight and cooking loss.

4.7 Effect of Ingredients on Texture of Instant Noodles

Texture of instant noodles is a very important characteristic and ingredients used play

important role in defining the textural properties. In general, consumers prefer the texture of

instant noodles to be firm with a good chewy bite (Kubomura 1998; Kim 1996b). The data in

Table 4.3 indicates that water absorption, alkaline salt and salt significantly affected (p<0.01)

the hardness of cooked instant noodles in linear terms.

4.4 Effect of (a) alkaline salt and water absorption (b) guar gum and alkaline salt on the

hardness of cooked instant noodles

Alkaline salt in interaction with guar gum decreased hardness but increased it with

water absorption significantly. Fig. 4.4a shows the effect of water absorption and alkaline salt

on cooked noodle hardness which increased considerably with increase in alkaline salt, while

decreased with increase in water addition. Furthermore, the noodles were observed to become

softer and thus unacceptable at higher water absorption level of 35% and lower alkaline salt.

However, by adding alkaline salt, the hardness improved, even at higher water absorption

level. Hatcher et al. (1999) also reported a significant decline in textural properties of oriental

noodles at higher water content. Interaction of alkaline salt and flour results in toughening of

(a) (b)


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dough and confers gum like texture to it (Terada et al. 1981) which is responsible for an

increase in hardness of cooked instant noodles. Alkaline salt were also reported to increase

the breaking and cutting force of noodles (Sung and Sung 1993).

Effect of alkaline salt and guar gum on hardness of noodles has been shown in Fig.

4.4b. It was noticed that alkaline salt increased the cooked noodle hardness. Addition of guar

gum decreased the cooked noodle hardness upto 0.4% incorporation level, whereas increased

it when incorporated above 0.4%. Shiau and Yeh (2001) observed that alkaline salt induces

the interchange of sulphydryl group and disulphide bond, which increases the G′ (storage

modulus), apparent viscosity of dough as well as tensile and cutting force in extruded

noodles.

4.8 Effect of Ingredients on Overall Acceptability of Instant Noodles

ANOVA analysis indicates that overall acceptability of instant noodles was significantly

affected by the linear (p<0.01) and quadratic (p<0.01) effect of the water absorption and guar

gum respectively (Table 4.3). Alkaline salt affected the overall acceptability of noodles in

linear term and also in interaction with guar gum and salt. Fig. 4.5a shows that overall

acceptability of noodles was higher at 31.0 to 33.2 % water addition and lower guar gum i.e.

0.3% with higher levels of both deteriorating the noodle quality to a significant level.

Fig. 4.5 Effect of (a) guar gum and water absorption (b) salt and alkaline salt on overall

acceptability score of instant noodles

(a) (b)


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This is as might have been expected because guar gum provides viscosity, improve firmness,

mouthfeel and rehydration characteristics of the product (Hou 2001) but higher levels may

result in protein network weakening as explained earlier. Fig. 4.5b on the other hand affirmed

that overall acceptability increased with the incorporation of alkaline salt and salt. The

alkaline conditions provided to dough by the alkaline salts confers unique flavour and yellow

colour; modifies pasting and dough properties; and improves the cooking, textural and surface

properties of the noodles. Therefore, alkaline salts improve the appearance, eating quality as

well as overall acceptability of the instant noodles. Table 4.4 indicates that water absorption

has a negative impact on the overall acceptability of noodles while alkaline salt and guar gum

have a positive effect. This may be attributed to the fact that higher water absorption as

mentioned above not only hampers the textural properties but also has a significant effect on

colour (Hatcher et al. 1999).

4.9 Optimization of Formula Ingredients

To obtain the optimal level of formula ingredients, numerical optimization was carried out.

The selection criteria for responses oil uptake and cooking loss was set to minimum because

higher values of oil uptake is not desirable as it increases the production cost and health

concerns. Higher cooking loss is associated with poor surface characteristics of noodles and

therefore reduces the acceptability of product. Overall acceptability was set to maximum.

Hardness and cooked weight of noodles was set towards higher range but not maximum as

noodles with maximum hardness or extra firm texture are not preferred by the consumers.

After applying these constraints, it was found that optimal levels for water addition, alkaline

salt, guar gum and salt were 30.97, 0.23, 0.28 and 1.54%, respectively. The adequacy of the

model for predicting optimum response value was verified by carrying out the analysis of

noodle prepared using the optimum levels of the ingredients.

Table 4.5 Predicted and actual response values at optimum level of ingredients

Response Predicted Value Actual Value Oil Uptake (%) 16.92 16.81 ± 1.06 Cooked Weight (%) 200.68 203.87 ± 2.87 Cooking Loss (%) 9.99 9.81 ± 0.97 Hardness (N) 40.00 39.67 ± 1.41 Overall Acceptability 76.16 77.13 ± 1.32

The results obtained showed that the experimental values were close to the predicted values,

thus, validating the optimal levels of ingredients studied (Table 4.5).


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4.10 Conclusion

It may be concluded from the present study that ingredients have an important role to play in

governing the quality of instant noodles. It was observed that although higher water inclusion

in the instant noodle formulation improved cooked weight it negatively affected the texture,

oil uptake, cooking loss, hardness as well as overall acceptability of the product. Alkaline

salt, however, reduced cooking loss and cooked weight; it had a positive effect on the overall

quality of instant noodles. Guar gum up to a maximum of 0.3% was found to be effective in

reduction of oil uptake and improving the quality of noodles. The optimum level of the

ingredients i.e. water absorption, alkaline salt, guar gum and salt were observed to be 30.97,

0.23, 0.28 and 1.54%, respectively at minimum level of oil uptake and acceptable quality of

instant noodles.

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Formula optimization of instant noodles - INFLIBNETshodhganga.inflibnet.ac.in/bitstream/10603/85473/12/12_chapter 4.pdf · Formula optimization of instant noodles . 58 fried noodles