Dosage of Additives and Shelf-life of Bread

Dosage of Additives

1. The capacity of my mill is 100 tons/day. I want to improve the flour with ascorbic acid and enzymes. What options do I have?

All! The improvers can be added separately or as premix, e.g. with middlings, using one or more micro-feeders of adequate dimensions. They can also be added in a batch process provided that a sufficiently large mixer is available.

2. We have to make a premix of flour improving agents with a carrier. What a carrier should we use?

The best shelf-life of the premix is achieved with calcium sulphate or carbonate as a carrier, but both increase the ash content of the flour. Starch and soybean flour are also possible, but expensive. Flour or middlings are another option, the latter having better flow properties.

If benzoyl peroxide (BPO) is to be used, the carries of choice are calcium carbonate, calcium sulphate or starch, because with one of the other carriers BPO would already lose part or all of its function in the premix.

3. We want to make a premix of vital wheat gluten and benzoyl peroxide. Will the BPO maintain its efficacy? And for how long?

BPO reacts with the small amount of lipids in the gluten and loses at least some of its oxidizing capacity. If the batch time can be limited to approx. 4 h, most of the bleaching effect will still be present.

Shelf-life of Bread

1. How can the microbial shelf-life of bread or pastry goods be prolonged?

Baked goods are almost sterile, or at least pasteurized, when they leave the oven. Microbial contamination occurs through re-infection. Re-infection can only be prevented by a sterile packaging area following the oven, or by a second heating step with the bread already wrapped in heat-stable packaging material. If this is not feasible, cooling of the baked goods is another option, but this accelerates the staling rate (see below). If no wrapping is applied, more extensive baking (and thus drying of the surface) improves resistance to mould growth.

Finally, preservatives help to suppress microbial growth.

In order to limit the off-taste caused by the preservative, combinations of several agents are recommended, e.g. propionate or sorbates with acetates.

Lowering the pH with sour dough or acidulants enhances the effect of the preservatives.

2. How can the shelf-life of the crumb softness be prolonged?

Storage at elevated temperatures, e.g. 40⁰C, prolongs the softness but increases the risk of mould spoilage. Ingredients that improve the specific volume improve the “offset softness” at the beginning of storage. A soft, silky crumb structure is a prerequisite for a good shelf-life, so all improvers that enhance the volume and the crumb structure also prolong the shelf-life of the goods.

Furthermore, some emulsifiers such as SSL, CSL, lecithin and monoglycerides slow down the rate of staling of the crumb.

Amylolytic enzymes with medium heat stability, which are able to survive the early stages of the baking process but are safely inactivated later, also enhance the softness of the crumb by inhibiting the staling process.