Gluten-free Bread With Benecel Modified Cellulose (HPMC)

Transcription

1 FOOD TECHNOLOGY REPORT Ashland Specialty Ingredients ashland.com FTR-025 Page 1 of 6 Gluten-free Bread With Benecel Modified Cellulose (HPMC) Introduction Consumers with celiac disease or gluten intolerance have increased the demand for gluten-free baked goods. Gluten plays a critical role in the bread making process because it gives so much functionality to the dough, making it difficult to replace. Gluten is composed of two primary components; glutenin and gliadin, which provide extensibility to the dough. This extensibility of the dough is an unique functionality of gluten and contributes to the high gas-holding properties and structure of the dough. 1 Many researchers have examined how to replace gluten effectively in bread. Crockett et al. 2 found that hydroxypropylmethylcellulose (HPMC; E464) increased volume and made a softer crumb in breads with a rice flour/cassava starch blend, and Hager and Arendt 3 found that HPMC works well to increase volume in breads made with various gluten-free flours. Crockett et al. also examined the rheology of gluten-free bread dough and found that HPMC increased the viscous behavior of dough, indicating better flexibility for gas expansion. This study examines how Benecel modified cellulose (which can be either hydroxypropylmethylcellulose, HPMC, or methylcellulose, MC) provides functional benefits in gluten-free bread compared with other hydrocolloids. Methods Gluten-free white bread was formulated and baked to compare Benecel HPMC with a competitive grade of HPMC, xanthan gum and a control containing no hydrocolloid. Each of the samples was evaluated for dough rheology during heating, height and texture of the finished bread as well as for retrogradation of starch as measured by differential scanning calorimetry (DSC). The hydrocolloids used are shown in Table 1. The formulation used for the bread is shown in Table 2. Table 1. Commercial hydrocolloid products used in gluten-free bread formulations Product Viscosity Specification % Hydroxypropyl % Methyoxyl Particle size (μm) Gel point ( C) Benecel mpa s at 2% Benecel K15M HPMC mpa s at 2% Competitive mpa s at 2% Xanthan gum mpa s at 1% 2 N/A N/A 171 N/A 1 Measured at 20 C at 20 rpm by Brookfield viscometer (Middleboro, MA). 2 Measured at 24 C at 60 rpm by Brookfield viscometer. All statements, information, and data presented herein are believed to be accurate and reliable, but are not to be taken as a guarantee, an express warranty, or an implied warranty of merchantability or fitness for a particular purpose, or representation, express or implied, for which Ashland assumes legal responsibility. Registered trademark, Ashland or its subsidiaries, registered in various countries. Trademark, Ashland or its subsidiaries, registered in various countries. *Trademark owned by a third party. 2014, Ashland. Rev

2 Page 2 of 6 Ingredient Table 2. Gluten-free bread formulation Control % Total Weight Test % Total Weight Deionized water Rice/tapioca flour blend (80/20) Corn starch Hydrocolloid Canola oil Sugar Egg white powder Dry yeast Salt Enzyme Baking powder Calcium tartrate Preparation 1. Mix yeast in warm (about 95 F/35 C) water until dissolved (about 5 minutes). 2. Combine all the dry ingredients together in a bowl and mix with a dough hook on low speed. 3. Add the water/yeast and oil to the bowl and mix for 2 minutes on low speed. 4. Turn mixer to medium speed and mix an additional 5 minutes. 5. Proof in bowl for 30 minutes at about 95 F/35 C. 6. Punch the dough down and roll out to the size of the bread pan, roll the dough up and place in a lightly greased Pullman loaf pan. 7. Proof in the pan for 30 minutes. 8. Bake at 350 F/177 C for 60 minutes. 9. Once cool, slice the bread to ½ in. (1.3 cm) thickness, wrap the loaf in plastic wrap then place in a bag.. Results and Discussion Dough Height Figure 1 shows how the dough expands as it is heated between two 25 mm cross-hatched discs in a nitrogenblanketed AR G2 rheometer (TA Instruments, New Castle, DE). Dough made with Benecel has similar expansion to the control, whereas doughs made with Benecel K15M HPMC and xanthan gum expand more than the control. Dough made with xanthan gum contracts significantly during baking and subsequent cooling, which has a negative effect on the final shape of the bread. Figure 2 graphs the average height of several loaves of baked bread. We can see that the final height of the bread mimics the pattern seen in the dough expansion. Breads made with Benecel K15M HPMC or xanthan gum are taller than the control.

3 Height of bread (cm) Gap (μm) Page 3 of Control (no hydrocolloid) Benecel K15M HPMC Benecel Xanthan gum Competitive Temperature Global Time (min.) Figure 1. Expansion of dough in heated rheometer Temperature ( C) Control, no hydrocolloid Competitive Benecel Benecel Xanthan gum K15M HPMC Figure 2. Height of baked loaves of bread Bread Firmness and Texture The dough is heated in the AR G2 rheometer from 77 F/25 C to 205 F/96 C (final internal temperature of baked bread) at a rate of 5 F per minute and is held at the final temperature for 30 minutes. The G results shown in Figure 3 indicate how firm the dough is as it heats. G is an index of the firmness of the dough, and rheologically, is the elastic or storage modulus, reflecting a solid component of the composition. The gluten-free dough made with Benecel K15M HPMC is the firmest dough from the start of the heating process and its firmness levels off as it is held at the final internal temperature of the bread (205 F/96.1 C). The control and xanthan gum doughs become much more firm as they are held at 205 F/96.1 C, while the dough made with Benecel remains the softest throughout the heating process.

4 Firmness (g) G' (Pa) Page 4 of 6 1.0E E E E+04 Control (no hydrocolloid) Benecel K15M HPMC Benecel Xanthan gum Competitive Temperature Temperature ( C) 1.0E Global Time (min.) Figure 3. Firmness of dough during heating Two slices of each of the finished loaves were tested using the American Association of Cereal Chemists (AACC) texture profile analysis (TPA) method on a TA.XT Plus from Stable Micro Solutions (Godalming, United Kingdom). A one-inch tapered probe was used and it was set to a depth of 25 mm at a rate of 2 mm per second. The results were averaged and indicated that gluten-free bread loaves made with Benecel K15M HPMC and xanthan gum were firmer than the control, whereas the gluten-free loaf made with Benecel was softer (see Figure 4) Control, no Competitive hydrocolloid Benecel Benecel K15M HPMC Xanthan gum Figure 4. Average firmness of bread as shown by compressive force using a TA.XT Plus texture analyzer

5 Resistance (g.sec) Firmness (g) Page 5 of 6 Frozen Versus Fresh Because much of the gluten-free bread produced in the United States is kept frozen for ease of distribution, we wanted to understand how this would affect the quality of the bread. The TPA method was used to measure firmness and stickiness. The results, shown in Figures 5 and 6, indicate that after freezing and defrosting most bread became softer compared with the fresh (never frozen) bread. The stickiness of the bread decreased after a freeze step except in the control, which became stickier. It should be noted than the bread containing xanthan gum was much stickier than the other loaves, which resulted in it sticking to the blades of the bread slicer Fresh Frozen Control, no Benecel hydrocolloid Competitive Benecel K15M HPMC Xanthan gum Figure 5. Firmness of bread, fresh versus frozen and defrosted, as measured by compressive force on a TA.XT Plus texture analyzer 0.00 Control, no hydrocolloid Benecel Competitive Benecel K15M HPMC Xanthan gum Fresh Frozen Figure 6. Stickiness of bread, fresh versus frozen and defrosted, as measured by tensile force on a TA.XT Plus texture analyzer

6 Page 6 of 6 Retrogradation of Starch The retrogradation of starch contributes to the staling of bread; to measure the retrogradation of starch in the glutenfree bread, we used a DSC2000 differential scanning calorimeter (DSC; TA Instruments, New Castle, DE) to track the change in retrogradation from day one to day five. The DSC temperature range was 10 C to 100 C at a rate of 5 C per minute. An empty aluminum pan was also run as a reference. DSC measures the endothermic enthalpy of the starch in the gluten-free bread and is reported in Joules per gram: we examined the change in Joules per gram from day one to day five. The products stabilized with hydrocolloids had a slower rate of retrogradation, or staling, than the control. Conclusions Table 2. Percent change in retrogradation, day one to day five Benecel K4M and K15M HPMC is a good choice for replacing the functionality of gluten in gluten-free bread. The unique thermal gelation capability of Benecel K4M and K15M HPMC grades are shown to improve the structure of the loaf during baking and maintain textural qualities over the shelf life by reducing the retrogradation of starch. Benecel K15M HPMC can help to improve the height and volume of gluten-free bread because it can help to stabilize and maintain gas cells created during fermentation through the baking process. Benecel HPMC is more beneficial than xanthan gum in gluten-free bread because it offers a better overall shape and bread volume and is less sticky, for easier cutting and processing. Ashland s technical experts are happy to assist product formulators by providing customer support and product guidance. References Trial Change day 1 to 5 (%) Control, no hydrocolloid 76 Benecel 67 Competitive 67 Benecel K15M HPMC 50 Xanthan gum Atwell, W. Composition of commercial flour. In Wheat Flour, pp , St. Paul, MN, Eagan Press, Crockett, R., P. Ie & Y. Vodovotz. How Do Xanthan and Hydroxypropyl Methylcellulose Individually Affect the Physicochemical Properties in a Model Gluten-free Dough? Journal of Food Science. 76(3) (2011): E274-E Hager, A.-S. & E.K. Arendt. Influence of Hydroxypropylmethylcellulose (HPMC), Xanthan Gum and Their Combination on Loaf Specific Volume, Crumb Hardness and Crumb Grain Characteristics of Gluten-free Breads Based on Rice, Maize, Teff and Buckwheat. Food Hydrocolloids. 32(1) (2012):