Editing Effect of Oats and Millet composition in Gluten-free Nutrient wafer (section)

== '''2. MATERIALS AND METHODS''' ==
# '''Preparation of Wafer'''

Following are the detailed steps of preparation of nutri wafer

'''2.1.1 Batter preparation'''

Millet flour, floured oats, milk powder, Sugar powder or honey and water mixed for 15 minutes to achieve a homogeneous batter using a high-shear mixer (Three compositions of wafer A, B, C Ref. Table 1). It is best suited because the slower mixers may allow formation of gluten lump and strands [10]. The suspension in cold water normally reduces the tendency of gluten lump formation. Immediately after mixing, the batter is mechanically beaten for air incorporation and kept it at room temperature avoiding high-temperature zones for settling.

'''2.1.2 Baking'''

The batter is set on a waffle machine to start the baking process. The baking is done in batch mode in the Wafer plate heating ovens. These ovens are made up of metal plates with side hinges, typically thin and usually bear smooth perforated surface patterns. The surface acts as heating surface as the metal on the surface has a very high heat transfer coefficient. The equipment runs with the consumption of electrical energy individually by 1000KWH. Electric coils and heating arrangement was at the lower side of the stack of plates. The batter is poured, in an array, across the lower plate, and on closing and locking with the upper plate, it rapidly produces steam that spreads over the batter evenly throughout the gap between the array of plates and the cover. It helps in the cooking and baking of the batter into a crisp form [11]. Some of the steam and heat was also venting out through the vents. The thickness of the wafers is proportional to the gap between the two plates.

'''2.1.3 Cooling cutting and wrapping'''

The wafers are cooled to 10-12<sup>o</sup>C using convective dry air circulation. The Relative Humidity (RH) of the air in the working chamber was kept as low as possible in the range of 15%<u>+</u>2% to avoid further moisture uptake by the exposed wafers during cooling [12]. After heat release immediately the waters were wrapped.

'''2.2 Shelf Life Study of the Wafers'''

The wafers were preserved in HDPE ziplock packaging material for three months at 25<sup>o</sup>C with 5% RH inside and 50% RH outside the pack. All the physicochemical and microbial analyses were performed with the preserved sample to estimate the shelf life. Sensory analysis was also performed just after preparation and 3 months later with the preserved product and the data was reported in 9 point hedonic scale with the average score of 25 panelists. The sensory analysis was performed in a separate sensory panel room [13].

'''2.3 Physical and Chemical Analysis of Wafer'''

Detailed analysis are given in the following paragraphs

'''2.4 Specific Gravity and Viscosity'''

Prior to baking specific gravity of the batter was measured with standard procedure and viscosity of the batter was measured using the falling sphere method following Stoke’s law. The samples were analysed in triplicate. Bulk density was measured using the dried and cooled wafer [14].

'''2.5 Thickness and Texture Analysis'''

Thickness was measured using Vernier sliding calipers for all the three (A,B,C) types of wafers. Mechanical properties of the wafers were investigated by using an automated Texture Analyzer (Brookfield, Middleboro, MA) Peak stress require to overcome the give Hardness/firmness was evaluated using compression force. Compression and fracturability tests were performed on wafer samples using a cylindrical probe Texture analyser (Microsystems) at a test speed of 1 mm/s. The load was calculated in terms of Newton (N) and correlated with the breakability by teeth and chewability. It was also correlated to the strength of the wafer texture to withstand any external mechanical force during carriage in the packaged form. The study was done with three or more samples for each of the cases. Most significant data (Pvalue ≤ 0.05 )and their average value was taken using standard statistical software [15].

'''2.6 Proximate Analysis'''

Moisture analysis was done in the Hot Air oven (SSU/Biolabs) with constant heating of 4.5 hrs. at 105<sup>o</sup>C. Fat estimation of the final product was done by Soxhlet extraction method. Total protein was measured using Kjeldahl method. Total reducing sugar was measured by Fehling’s method. The final moisture content was measured on both dry basis and wet basis. Crude fiber was detected by gravimetric method following acid and alkaline digestion. The moisture analysis was also done for the sample preserved for three months. The ash or total mineral content was measured by muffle furnace at 550<sup>o</sup>C for 24 hrs [16].

'''2.7 Nutritional Analysis'''

Nutritional analysis of the final product was done using the Atwater system measuring the total nutritional components (protein, fat and carbohydrate) and their calorific contribution. Considering 4 Kcal /Kg of carbohydrate or Protein and 9 kcal/ Kg of the total nutritional composition for fat components. The nutritional score was assessed using the above-mentioned method [17].

'''2.8 Microbial Analysis'''

The preserved samples were tested for microbial safety specifically for yeast and mold infection. Both vegetative and spore forms were tested by microscopic examination. The tests were conducted for dry wafer and the value expressed in cfu/gm of the food item (wafer) for each type (A,B,C) after preservation [18].

'''2.9 Sensory Analyses'''

Through sensory analysis, characteristics like texture, flavor, taste, appearance, smell of the wafers were measured from the panelists. Panelists (twenty five in numbers) were allowed to sit in a panelist's room and scored in a double blinded way. The test is performed for purpose of accepting or rejecting food products using 9- point hedonic scale.

'''2.10 Market Survey of Gluten Based Nutri-wafer'''

A market survey was performed in the local area, nearby rural, few urban and semiurban areas of West Bengal where rice, wheat and potato-based products are more popular. A questionnaire was given to the common consumers to determine their level of acceptability of the millet Nutri-wafer. At the time of the survey the consumers were allowed to taste the product if they liked to. From this data the potentiality of market acceptance of the product was estimated. A detailed cost analysis was also performed with the millet-based Nutri-wafer to support its market potential [19,20].