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CHAPTER 111

METHODOLOGY

3.1 Box and Behnken Design

The Box-Behnken design is an independent quadratic design that does not contain

an embedded factorial or fractional factorial design. In this design the treatment

combinations are at the midpoints of edges of the process space and at the center. These

designs are rotatable (or near rotatable) and require 3 levels of each factor. The designs

have limited capability for orthogonal blocking compared to the central composite

designs.

Figure 2: This figure shows the Box and Behnken Design for Three Factors

The geometry of this design suggests a sphere within the process space such that

the surface of the sphere protrudes through each face with the surface of the sphere

tangential to the midpoint of each edge of the space.

For three factors, the Box-Behnken design offers some advantage in requiring a

fewer number of runs. For 4 or more factors, this advantage disappears.

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Table 5: This table shows the Camote Flour, Fat, Cake Flour and its parameters

Camote flour (X1) Fat (X2) Cake flour (X3)

+1 = 45 +1 = 25 +1 = 45

0 = 40 0 = 20 0 = 40-1 = 35 -1 = 15 -1 = 35

Coded

Table 6: This table shows the Coded samples of Camote flour, Fat, Cake Flour and the different

formulations

X1 X2 X3

1 +1 -1 02 -1 -1 0

3 +1 0 +1

4 -1 +1 +1

5 +1 +1 +1

6 -1 0 0

7 0 +1 -1

8 0 -1 +1

9 0 0 0

10 -1 -1 -1

11 -1 +1 0

12 0 -1 -113 0 +1 +1

14 0 +1 +1

15 0 +1 +1

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Uncoded

Table 7: This table shows the Uncoded samples of Camote flour, Fat, Cake Flour and the different

formulations

X1 X2 X3

1 45 15 40

2 35 15 40

3 45 20 45

4 35 25 45

5 45 25 45

6 35 20 40

7 40 25 35

8 40 15 45

9 40 20 40

10 35 15 35

11 35 25 40

12 40 15 35

13 40 25 45

14 40 25 45

15 40 25 45

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3.2 Materials

Table 8: This table shows the Raw Materials, Quantity, Unit and Specifications

Raw Materials Quantity Unit Specifications

Sweet Potato * Kilograms fresh

Cake flour * Kilograms

Sugar 50 Grams refined

Baking powder 2 Grams

Salt 0.5 Grams

Egg 55 Grams fresh

Milk 100 Milliliter evaporated

Butter * Kilograms*Quantity depends on different formulations

Sweet Potato

The sweet potato (Ipomoea batatas), commonly

called a yam in parts of the United States (especially in the

southern and western portions of the country; this

terminology causes some confusion with true yams), is a

crop plant whose large, starchy, sweet tasting tuberous

roots are an important root vegetable.Figure 3: Shows the raw sweet potato

Cake Flour

Soft flour is comparatively low in gluten and so results in a

finer texture. Soft flour is usually divided into cake flour,

which is the lowest in gluten, and pastry flour, which has

slightly more gluten than cake flour.

Figure 4: Shows the cake flour

Sugar

Sugar (the word stems from the Sanskrit sharkara) consists

of a class of edible crystalline substances including sucrose,

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lactose, and fructose. Human taste-buds interpret its flavor

as sweet.

Figure 5: Shows the sugar

Baking Powder

Baking powder is a dry chemical used in cookery, mainly

baking. Traditional baking powder was composed of a

mixture of tartaric acid and bicarbonate of soda (baking

soda), a quantity of flour usually being added to reduce the

strength.

Figure 6: Shows the baking powder

Salt

Salt is a dietary mineral essential for animal life, composed

primarily of sodium chloride. Salt for human consumption

is produced in different forms: unrefined salt (such as sea

salt), refined salt (table salt), and iodised salt. It is a

crystalline solid, white, pale pink or light grey in color,

normally obtained from sea water or rock deposits. Edible

rock salts may be slightly greyish in color due to this

mineral content.

Figure 7: Shows the salt

Egg

An egg is a round or oval body laid by the female of many

animals, consisting of an ovum surrounded by layers of

membranes and an outer casing, which acts to nourish and

protect a developing embryo and its nutrient reserves.

Figure 8: Shows the chicken egg

Milk

Milk is an opaque white liquid produced by the mammary

glands of female mammals (including monotremes).

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Figure 9: Shows the milk

Butter

Butter is a dairy product made by churning fresh or

fermented cream or milk.

Figure 10: Shows the butter

Muffin

A muffin is somewhat like a small cake, and though it doesresemble a cupcake: they have cylindrical bases, rounded

conical tops, and are usually not as sweet as cupcakes;

savory varieties (such as cornbread muffins) also exist.

They generally fit in the palm of an adult hand, and are

intended to be consumed by an individual in a single

sitting.

Figure 11: Shows the muffin

3.3 Utensils and Equipment

Table 9: This table shows the utensils and equipment that are used in sweet potato muffin.

Description Quantity Specification Source

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Knife

Chopping board

Utility tray

Mixing bowl

Dietetic scale

Ladle

Casserole

Cookie sheet

Strainer

Peeler

Oven thermometer

Measuring cup (liquid)

Measuring cup (solid)

Measuring spoon

2 pcs.

2 pcs.

2 pcs.

1 set

1 unit

1 pc.

1 pc.

2 pcs.

1 pc.

2 pcs.

1 unit

1 set

1 set

1set

Metal

Metal

Metal

Metal

Metal

PFP storage room

PFP storage room

PFP storage room

PFP storage room

PFP storage room

PFP storage room

PFP storage room

PFP storage room

PFP storage room

PFP storage room

PFP storage room

PFP storage room

PFP storage room

PFP storage room

The raw materials used were of good quality fresh sweet potato of Ipomoea

Batatas specie, of medium size and yellow color; cake flour, refined sugar, baking

powder, salt, fresh egg, evaporated milk and butter. The utensils were borrowed from

PUP Pilot Plant.

Process Flow of Sweet Potato Muffin

Selection of Raw Materials

Preparation of Raw Materials

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Peeling

Slicing

Soaking

Sun Drying

Oven Drying

Sorting

Grinding

Mixing

Baking

Cooling

Packing

Labeling

StoringFigure 12: This figure shows the Process Flow of Sweet potato muffin

3.4 Process in Making Sweet Potato Muffin

3.4.1 Selection and Preparation of Raw Materials

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Quality assurance was employed in checking the quality of the raw sweet

potato that will be used in making sweet potato noodles. It was test according to

color, appearance and texture.

Any soil on the roots must be removed before the root is peeled using a

clean kitchen knife. Any damaged parts of the raw sweet potato should be

trimmed off.

3.4.2 Peeling

The skin of sweet potato is peeled using a clean kitchen knife.

3.4.3 Slicing / Chipping

After washing, the sweet potatoes are dried in a clean place in the sun for

about 10 minutes to remove the surface water. A manual or mechanical chipper /

slicer is then used to cut the sweet potato into uniform pieces.

3.4.4 Soaking

Slices are soaked in clean tap water for 5-10 minutes. The volume of water

used is twice the weight of the slices and is just enough to cover all the slices.

3.4.5 Drying (Sun Drying and Oven Drying)

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The slices are then either sun dried on a raised tray for approximately 4-6

hours if weather conditions are suitable, or in an oven dryer. The drying tray

should be raised off the ground to prevent dust and dirt contaminating the chips. If

drying rate will depend on the thickness of the slices, rate of turning chips as they

dry and the amount of sliced chips place on the tray.

3.4.6 Sorting and Grinding

The dried sweet potato chips can now be milled into flour. The dried sweet

potato chips can be sorted for uniformity before packaging or further processing,

if this might affect the quality, intended use or price.

3.4.7 Mixing

In a large bowl, combine sweet potato flour, cake flour, sugar, baking

powder, salt, egg, milk and butter based on different formulations.

3.4.8 Baking

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Pre-heat the oven. Bake the muffin at 200C (400F) for 20-25 minutes.

3.4.9 Cooling

Turn onto wire racks to cool.

3.4.10 Packing and Storage

Sweet potato muffin can be safely packed and stored in polythene bags as

well as baskets and tins.

3.5 Methods of Evaluation

The different finished products of muffin made from the sweet potato flour were

evaluated. The formulations were different in percentage of the three (3) variables (Sweet

potato flour, Fat and Cake Flour). Finished products were subjected to sensory

evaluation.

3.6 Subjective Evaluation

The fifteen (15) experimental samples were coded with random numbers. All the

product samples including the Control were presented to a panel of ten (10) students for

sensory evaluation. Samples were labeled identically and were placed in identical paper

plates and each panelist were asked to evaluate the experimental samples according to the

paneling parameters namely; color, texture, taste / flavor, tenderness, odor / aroma, and

firmness.

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Panelists were asked to strictly follow the instruction given in the score sheet. It

was important that the panelist drank or gargled with water to remove any lingering taste

or flavor brought about by the previous sample.

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Flow Chart

Selection of Raw Materials

Preparation of Raw Materials

Peeling

Slicing

Soaking

Sun Drying

Oven Drying

Sorting

Grinding

Subjective Evaluation Objective Evaluation

Mixing

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Baking

Cooling

Subjective Evaluation Objective Evaluation

Packing

Labeling

StoringFigure 13: This figure shows the flow chart of Sweet Potato Muffin

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3.7 Objective Evaluation

The best produced finished product which is formulation 12 was subjected to

microbial analysis wherein yeast and mold count were determined.

3.7.1 Microbial Analysis

3.7.1.1 Yeast and Mold Count

One gram of sample was weighed and dissolved in 99 ml. distilled water in an

Erlenmeyer flask, serial dilution was made by transferring one ml of diluted sample to a 9

ml. of distilled water as 1:10. Further dilution were made as 1:1000, one ml. of each

dilution was transferred into a petrifilm. Incubated for 24 hrs. at 25C in incubator. After

incubation, number of colonies of at least 2 plates was counted, rounded up to 2

significant figures. Then, was multiplied by the dilution of the water (Bryan, 1973).

3.7.1.2 pH Count

pH can be measured:

by addition of a pH indicator into the solution under study. The indicator color

varies depending on the pH of the solution. Using indicators, qualitative determin-

ations can be made with universal indicators that have broad color variability over

a wide pH range and quantitative determinations can be made using indicators

that have strong color variability over a small pH range. Precise measurements

can be made over a wide pH range using indicators that have multiple equilibri-

ums in conjunction with spectrophotometric methods to determine the relative

abundance of each pH-dependent component that make up the color of solution,

or

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by using a pH meter together with pH-selective electrodes (pH glass electrode,

hydrogen electrode, quinhydrone electrode, ion sensitive field effect transistor and

others).

by using pH paper, indicator paper that turns color corresponding to a pH on a

color key. pH paper is usually small strips of paper (or a continuous tape that can

be torn) that has been soaked in an indicator solution, and is used for approxima-

tions.

3.7.2 Proximate Analysis

3.7.2.1 Ash

Ash is the inorganic residue remaining after the water and organic matter have

been removed by heating in the presence of oxidizing agents, which provides a measure

of the total amount of minerals within a food. Analytical techniques for providing

information about the total mineral content are based on the fact that the minerals can be

distinguished from all the other components within a food in some measurable way. The

most widely used methods are based on the fact that minerals are not destroyed by

heating, and that they have a low volatility compared to other food components. The

three main types of analytical procedure used to determine the ash content of foods are

based on this principle: dry ashing, wet ashing and low temperature plasma dry ashing.

The method chosen for a particular analysis depends on the reason for carrying out the

analysis, the type of food analyzed and the equipment available. Ashing may also be used

as the first step in preparing samples for analysis of specific minerals, by atomic

spectroscopy or the various traditional methods described below. Ash contents of fresh

foods rarely exceed 5%, although some processed foods can have ash contents as high as

12%, e.g., dried beef.

3.7.2.2 Moisture

Weigh out 5 g of sample into a tared porcelain crucible or aluminum drying dish

spreading the sample as thin as possible over the base of the dish. Put the dish and

contents in an oven maintained at 105C and dry for 4 hrs. Remove cool in a dessicator

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and weigh.Return the dish to the oven and ready for a further 30 minutes. Remove, cool

and weigh. Continue drying until a constant weigh has been reached. Calculate the

moisture content from the weight loss of the sample.

Calculation:

% Moisture = Initial Weight Final Weight x 100

Weight of Sample Used

3.7.2.3 Crude Protein

Laboratories measure the nitrogen (N) content of the forage and calculate crude

protein using the formula: CP = % N x 6.25. Crude protein will include both true proteinand non-protein nitrogen. Cattle can use both types to some varying degree. Crude

protein values give no indication if heat damage has occurred, which may alter protein

availability.

3.7.2.4 Crude Fat

The traditional method for the analysis of fat was developed by German chemist

Franz von Soxhlet in 1879. Essentially, the sample is suspended between a flask of

boiling solvent and a condenser. The solvent evaporates, is condensed onto the sample,

and thereby extracts the fatty matter en route back to the bulk solvent. Since freshly

distilled solvent is continually contracting the sample, the solute's affinity for the solvent

continues until the extraction is complete. By evaporating the excess solvent, the residual

matter is quantified gravimetrically as fat. Soxhlet's procedure was significantly

improved in 1974 by American chemist Edward Randall. The Randall technique

immerses the sample in boiling solvent and then continuously elutes the sample with

freshly condensed solvent.

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3.7.2.5 Total Carbohydrates

By difference :

This involves obtaining the variable carbohydrates content by calculation having

estimated all the other fractions by proximate analysis as shown below:

% Available Cabohydrates = 100 % - (% Moisture + % Ash + % Fat + % Protein

+ % Fibre)

3.8 Cost Evaluation

The cost of the product must be evaluated based on raw materials used in the

preparation including utilities and packaging material, production cost and mark-up

which is based on the weight of every formulation of each product.

Table 10: This Table shows the cost analysis of sweet potato flour

Unit Cost Quantity Actual Cost

Sweet Potato 28.00 / kg 3 kg 84.00

Overhead Cost

Labor (minimum) 15.00 / hr 3 hrs 45.00

Electricity 5.00 5.00Water 2.00 2.00

Fuel 10.00 10.00

Packaging 5.00 5.00

Total Cost 67.00

Unit Cost 151.00

10% mark-up 15.10

Selling Price 166.10 / kg

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Table 11: This table shows the cost analysis of sweet potato muffinS-45

C-40

F-15

S-35

C-40

F-15

S-45

C-45

F-20

S-35

C-45

F-25

S-45

C-45

F-25

S-35

C-40

F-20

S-40

C-35

F-25

S-40

C-45

F-15

S-40

C-40

F-20

S-35

C-35

F-15

S-35

C-40

F-25

S-40

C-35

F-15

S-40

C-45

F-25

S-45

C-40

F-25

S

C

F

Unit

Cost

Quantity F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12 F13 F14 F

weet Potato

lour

166.1 /

kg

7.5 5.8 7.5 5.8 7.5 5.8 6.6 6.6 6.6 5.8 5.8 6.6 6.6 7.5 6

Cake Flour 38 / /kg 1.5 1.5 1.7 1.7 1.7 1.5 1.3 1.7 1.5 1.3 1.5 1.3 1.7 1.5

ugar 35 / kg 50 g 1.75

Bakingowder 16 / 100g 2 g 0.32

alt 6 / kg 0.5 g 0.00

3

Egg (137.5 /

c)

35 / pc 55 g 1.4

Milk 20/100

ml

100 ml 20

Butter 35 / kg 0.53 0.53 0.7 0.88 0.88 0.7 0.88 0.53 0.7 0.53 0.88 0.53 0.88 0.88 0

Total Cost ofngredients

33.00

31.3 33.37

31.85

33.55

31.47

32.25

32.3 32.27

31.1 31.65

31.9 32.65

33.35

3

Overhead Cost

Labor

minimum)

15.00 /

hr

1 hr 15.0

0Electricity 5.00 5.00

Water 2.00 2.00

uel 8.00 8.00

ackaging 5.00 5.00

Total Cost 35.0

0

35.0

0

35.0

0

35.0

0

35.0

0

35.0

0

35.0

0

35.0

0

35.0

0

35.0

0

35.0

0

35.0

0

35.0

0

35.0

0

3

Unit Price 68.00

66.3 68.37

66.85

68.55

66.47

67.25

67.3 67.27

66.1 66.65

66.9 67.65

68.35

6

0% mark-up 6.80 6.63 6.837

6.685

6.855

6.647

6.725

6.73 6.727

6.61 6.665

6.69 6.765

6.835

6

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elling Priceer 12 pcs.

74.8 72.93

75.21

73.54

75.41

73.12

73.98

74.03

74 72.71

73.32

73.59

74.42

75.19

7

elling Priceer pc.

6.23 6.08 6.27 6.13 6.28 6.09 6.17 6.17 6.17 6.06 6.11 6.13 6.2 6.27 6

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