7. CONCLUSIONES REFLEXIONES Y PROBLEMAS ABIERTOS
7.3 Problemas abiertos y futuras líneas de investigación
3.2.1.1 Experimental design
Figure 3.1 overviews the four main stages involved in the development of wheat bread containing mozuku and its analysis (loaf quality testing, consumer evaluation and microbial stability testing). The four main stages comprised of: base formulation, addition of mozuku, consumer sensory evaluation and testing for microbial stability during storage.
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Figure 3.1 Overview of the experimental procedures used in the development and testing of
wheat bread containing mozuku powder
3.2.1.1 Base formulation
The method for the production of a standard wheat bread loaf was based on the standard AACC International method 10-10.03 (AACC International, 1999a). The standard did not state amounts of water required to be added to the bread formulation. Therefore, the amount of water used in the formulation was obtained from previous studies (Phillips, 2000; Scott & Wing, 1999). Table 3.3 shows the wheat bread formulations prepared according to procedures described in Section 3.2.3.
Microbial
Stability
Testing
Consumer
Testing
Addition of C.
cladosiphon
Base
Formulation
Formulation 1 - (AACC 10- 10.03) Formulation 2 - 0% Mozuku (Control) Formulation 2 - 0% Mozuku (Control) Formulation 2 - 0% Mozuku (Control) Formulation 3 - 1% Mozuku Formulation 4 - 2% Mozuku Formulation 5 - 1% Mozuku, Reduced salt Formulation 5 - 1% Mozuku, Reduced salt Formulation 5 - 1% Mozuku, Reduced salt Formulation 6 - 2% Mozuku, Reduced salt Formulation 6 - 2% Mozuku, Reduced salt Formulation 6 - 2% Mozuku, Reduced salt56
Table 3.3 Base formulation for standard wheat bread
3.2.1.2 Addition of mozuku powder to standard white wheat bread
In stage 2, mozuku was added at 0% (control), 1% and 2% (w/w baker’s percentage). Selected concentrations of added mozuku were based primarily on cost – ideally, to keep the concentration low so that the final product remained affordable for low income populations. At the same time, the final product with mozuku should contain additional nutritional benefits over a standard wheat loaf while retaining acceptable bread quality parameters. Formulations 2, 3 and 4 as shown in Appendix A, were produced following procedures described in Section 3.2.3 and tested according to the bread quality parameter tests set out in Section 3.4.
3.2.1.2 Adjustment of sodium chloride concentration in wheat bread formulation containing mozuku
Formulations 5 and 6 were formulated with added mozuku and adjusted salt concentrations by removing 0.5% table salt for every 1% mozuku added (baker’s percentages). Wheat bread formulations 5 and 6 as shown in Appendix A, were produced following procedures described in Section 3.2.3 and tested according to the procedures set out in Section 3.4.
3.2.3 Production of wheat bread
3.2.3.1 Dough mixing
All the ingredients were weighed using a Sartorius top pan balance (CP4202s, Goettingen, Germany) according to each formulation (Appendix A). Two 100 mL portions of potable water (30°C) were weighed into two 500 mL plastic beakers, sugar and salt were added to one beaker of warm water
Ingredient % Flour (w/w) Weight (g)
Flour 100 300 Yeast 5 15 Salt 1.5 4.5 Sugar 5 15 Soybean oil 3 9 Water 66 198
57 (30°C) and stirred with a spoon until dissolved. The active dried yeast was added to the remaining beaker, stirred and allowed to activate for 10 min. Flour and mozuku powder were weighed (Sartorius CP4202s, Goettingen, Germany) into an 8-L Delta Planetary Mixing bowl (Delta 8L Planetary Mixer, Delta Faucet, New Zealand) and a well was formed in the centre of the flour to contain the liquids. The sugar-salt solution, activated yeast solution, remaining water and soybean oil were then added to the pocket in the flour. To mix the ingredients, a dough hook was attached to a planetary mixer (Delta 8L Planetary Mixer, Delta Faucet, New Zealand) and used to mix the dough to an optimum dough consistency as determined by the windowpane test. During the windowpane test a small sample of dough (30 – 50 g) was removed by hand and rolled into a ball. The rolled dough was then held between the thumb and forefingers and gently spread into a thin translucent membrane as shown in Figure 3.2, the sample was then return to the dough. If the dough did not tear during spreading, the dough had been sufficiently kneaded (Campbell Todd, personal Communication, 25 February, 2016, Bakels NZ). Optimum mixing time for dough development using a Delta 8L Planetary Mixer, (Delta Faucet, New Zealand) was determined to be 13 min at setting 1, followed by 1 min at setting 2.
Figure 3.2 Windowpane testing: Progressive spreading of dough to a thin translucent
membrane
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3.2.3.2 Dough fermentation, proofing and shaping
After mixing, the dough was transferred to a lightly greased stainless steel bowl capable of accommodating a volume increase of at least 300%. The bowl with mixed dough was covered with plastic food wrap (Gilmours Cling Wrap 380 mm x 300 M, Gilmours Ltd, NZ) and the dough was left to rise at ambient temperature (20°C) for 50 min. The dough was then removed from the bowl and placed onto a clean stainless steel bench that had been lightly dusted (sprinkled) with flour. The dough was ‘punched down’ using an open palm and a wooden rolling pin to flatten it to a thickness of about 5 mm (AACC International, 1999a). The flattened dough was then folded in half twice and placed back into the stainless steel bowl, covered with plastic food wrap and left to rise for an additional 25 min at ambient temperature, following which the dough was removed from the bowl and the punch down step was repeated. The dough was then placed back into the bowl for a further 13 min, and then removed for shaping to the size of the bread pan (220 x 120 x 60 mm). The shape dough was placed ‘seam down’ into a lightly greased 500 g bread pan and covered with aluminium foil (Gilmours foil 440 mm x 90 M, Gilmours Ltd, NZ). The dough was then allowed to proof at ambient temperature for 35 min, thus completing bread dough preparation.
3.2.3.3 Baking, cooling and packaging
A convection oven (Turbofan 32Max, Moffat Pty Ltd, New Zealand) was preheated to 200°C and then steamed for 10 seconds prior to baking (Le-bail, Dessev, Leray, Lucas, & Mariani, 2011). Following removal of the aluminium foil covering the bread pans, the bread pans containing the dough were baked for 25 min. The bread loaves were removed from the bread pans and placed onto cooling racks to cool for 3 hours at ambient temperatures (20°C) before being packaged. Each loaf was packaged in a perforated polyethylene bread bag (350 x 445 mm) and stored in a slightly aerated container at ambient room temperature (20°C) out of sunlight prior to bread quality testing.
3.2.3.4 Analyses of wheat bread
Samples of wheat bread were analysed using standard methods described in section 3.4, 3.5 and 3.6. The samples were analysed for colour, texture, and water activity, and bread volume was determined. Consumer sensory evaluation was carried out on the products using a 9 point hedonic scale. Total
59 plate counts and, yeasts and moulds were also analysed. All analysis took place within 12 hours of baking, except in the case of the microbial stability testing which took place after 1, 2 or 3 days of storage.