Pre-fermented bakery ingredients produced with sustainable biotechnological processes

Industrial prototypes of novel bakery products with pre-fermented ingredients are being developed by INGREEN. These prototypes will have improved shelf life and enhanced nutritional and sensory properties. The pre-fermented ingredients are developed by using a new sustainable biotechnological fermentation process that is based on tailored microbial consortia of GRAS (generally recognised as safe) yeasts and lactic acid bacteria. These selected microorganisms use milling by-products that would have otherwise gone to waste to create new food ingredients.

The pre-fermented ingredients are made from wheat and rye bran, which is a side stream of the milling process. Our industrial partners, Barilla and Pivetti produce a wide range of pasta, bakery products and flour respectively, and consequently also produce a vast amount of rye and wheat bran. When wheat is processed, about 75% of the mass produces flour and the remaining 25% consists of by-products. The latter is currently mainly used in the feed sector and its application in the food sector is still limited despite the wide nutritional and functional potential. Barilla mainly produces durum wheat semolina that is used for pasta production. Each month, Barilla produces 16,000 tons of milling by-products.

INGREEN aim is to turn the milling side stream feedstocks that are currently used in the feed sector into valuable compounds to be used for the bakery industry. It requires the project partners not only to develop processes to recover the right compounds from the feedstock but also to identify the right microbes that can transform the compounds into useful ingredients for bakery ingredients.

To start with, the feedstocks were characterized by evaluating them for e.g., proteins, humidity​, soluble fibre​, fat and fatty acids profiles, starch and phytic acid. Additionally, the microbial consortia used to produce the nutritional pre-ferments were composed of selected and characterised yeasts and lactic acid bacteria isolated from the same by-products or typical sourdough. Subsequently, the researchers tested different mixtures of the milling side stream feedstocks combined with various microbial consortia to assess which combination produced the best pre-fermented ingredients from a technological, functional and sensorial point of view.

In the laboratory, the project partners scaled up the production of selected preferments to batches of 10 kg which is sufficient to produce at least 100 kg of bakery products. In the next phase, preliminary dough tests were carried out to determine what percentage of preferments can be used in the dough recipe at industrial level. The analysis included looking at the overall appearance, colour, flavour, crunchiness, gumminess and hardness of the laboratory bread prototypes. It was concluded that the use of 20% of preferment (on flour) in the bakery recipe resulted in the best outcomes and therefore was selected for the trials in an industrial environment.  

The bioactivity of the preferment ingredients selected for bakery application was compared to unfermented mixtures and mixtures fermented by a commercial bakery yeast. All the tested innovative preferments have shown excellent nutritional and functional properties. However, the scoring varied depending on the milling by-products mixture and the microbial consortium used. ​All preferments produced with the INGREEN biotechnological approaches showed an increase of short-chain fatty acids, antioxidant activity, total phenol content and bioactive peptides compared to the controls. These compounds are known to have health benefits.

Below are photos of the most recent prototypes of preferments produced by the University of Bologna and bakery products produced with the same preferments in Barilla pilot plant

Figure 1. The appearance of the INGREEN preferment MIX 7 post-fermentation produced by the selected microbial consortia on the right and the benchmark, a commercial bakery yeast, on the left. The fermentation by the selected microbial consortia improved the colour and appearance of the preferment compared to the benchmark.

Figure 2. An overview of the steps taken to add the developed pre-ferments to the bread prototypes.
Figure 3. Bread prototypes obtained at Barilla pilot plants during INGREEN project with liquid and lyophilized (powder) preferments compared to two benchmarks, one without preferment and the other prepared with the unfermented milling by-products mixture.

As INGREEN continues, the project partners will continue their work to characterize the two best bread prototypes, produced at industrial scale, for shelf-life, textural, sensory and nutritional profiles.          

INGREEN will develop functional innovative ingredients from paper and agro-food side streams through biotechnological processes for food, feed, pharma/nutraceutical, cosmetics and bio-degradable packaging.  The project seeks to obtain at least 20% more value from the project side-stream feedstocks than current state-of-the-art methods and create new cross-sector interconnections in the bio-based economy.

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