Going Bananas: Sponge Cake Variant

 Baking Trials 025, 18 May 2013

After many fruitless forays into gluten-free Golden Sponge Cakes, I have decided to get on course with variations of wheaten formulas that are tried and true.

Thus I thought I would take on a Banana Bread variant to the Sponge Cake. Notice I do not say “Golden”, for after the addition of the banana and other ingredients the golden has given way to a lovely speckled brown.

Also here a gluten-free trial was bolted on, for I was curious about the latest GF mix to hit the market, the Cup4Cup brand: can it really deliver on its claimed/implied promise of successful 1:1 substitution for wheaten flour?

After some tweakage to the usual overly-moist, leaden-textured recipes that characterize classic banana breads, I tried the following:

Banana Pulp      250g (well-freckled, ripe)
 
 either:
A: Cake Flour    200g (wheaten variant)
 or:
B: All-Purp. GF  200g (gluten-free variant: "Cup4Cup" brand)

Raisin Slurry    150g (75g each water & raisins, pureéd)
Oil, Sunflower   109g
Egg_Whites        73g (from 2 eggs, separated)
Honey             60g
Sugar, superfine 120g (60g batter + 60g French meringue)
Egg_Yolks         37g (from 2 eggs, separated)
Baking Powder    9.2g (aluminum-free)
WPC-80           8.5g (whey protein concentrate, lecithinated)
Baking Soda      4.6g
Salt, Sea        3.6g
Vanilla Extract  4.2g (~1 tsp.)
Spice, Cinnamon  2.6g
Spice, Nutmeg    1.2g
Spice, Cloves    0.5g
Ascorbyl Palmitate 400mg (fat-soluble Vitamin C; antioxidant)
Lemon extract      3 drops
Vitamin-E Oil      3 drops (antioxidant)
 
Preparation was similar to prior chiffon-based batter methods (see other entries this weblog): beat egg yolks, prepare an emulsion by whipping in a slow drizzle of oil, mix in wets, stir in sifted drys (GF only: beat the batter well), and finally fold in French chiffon (egg whites to soft peak, then 1/2 sugar).

It was noted that the Cup4Cup GF variant was nasty to mix: the batter tended to “wind up” around the mixer blades, a behavior attributable to an excess of xanthan gum, and possibly pregelatinization of GF mix starch fractions.

Standard baking: 18min. at 320°F in canoe pans over boiling-water pan. Canoe cups prepped with shortening with nonstick overspray. Pan release is clean.

Analysis of ingredients and outcome provides these figures for this trial:

Figure     per 38.8g wheaten cake
Protein    1.9g
Fats       5.5g
Starches  10.7g
Fiber      0.7g
Sugars    11.2g
Sodium     290mg
Energy    136kCal


Yield for the wheaten formula is 22 cakes. Analysis for the Cup4Cup GF substitution is about 9% lower due to the batter having a lower density, yielding 24 cakes.
 
The wheaten variant has good texture, flavor, and aroma. The added spices, not typical in banana bread recipes, seem to compete with the banana aroma, but using dead-ripe bananas may help to offset.

Strangely the GF variant seemed to have less apparent banana aroma. Typically, but no different from all other GF mixes offered today and tried so far, cake rise was scary-dramatic, and postbake shrink remarkable and dreadful.
 
Cup4Cup-formulated sponge cakes were about 25% less in final volume, with a typically rubbery-gummy texture—not the worst results compared to that of other GF mixes, but still not good or satisfactory.

Cup-for-cup—whether as a baking approach or as a silly trademarked name—has proven once again to be a fantasy in naively converting traditional wheaten formulas to gluten-free.

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Sugar composition, sugar-starch balance, and raisin inclusion have been adjusted within the limits of a workable formula to maximize shelf life vis-à-vis retardation of staling, retention of moisture, and resistance to microbial spoilage.

Sensory evaluation & comments from the Browne Crowe Bakes Sensory Evaluation Team:

• Not heavy, dense, or overly sweet as is usual with banana breads
• Good banana aroma; could be stronger?
• Wheaten variant (nice sponge) better than GF (a bit gummy)
• Tender & moist crumb

Overall the outcome of Trial 025 (wheat) is satisfactory.

The next trials contemplated will leave off xanthan- or guar-gum based GF flour substitutes, and go with a from-scratch rice-potato-tapioca base using milled flaxseed as a binding agent. Previous trials by the author (not yet reported here) of modified Yellow Cake GF formulations using flax have produced encouraging results.

Beekeeping for Poets

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