Wasted Bread as Substrate for the Cultivation of Starters for the Food Industry

Abstract

The amount of bread wasted daily worldwide, throughout its entire lifecycle, from production to distribution, is estimated to be hundreds of tons, therefore representing both economic and environmental issues. This work aimed at the valorization of wasted bread, setting-up a protocol for obtaining a growth medium to be used for the cultivation of food industry microbial starters. The optimization of the protocol included the set-up of parameters for the hydrolysis of the bread nutrient compounds with proteolytic and amylolytic enzymes and the supplementation with nitrogen and/or carbon sources. The suitability of the optimized medium for the growth of lactic acid bacteria, yeasts and fungi from dairy, bakery, and wine industries was assessed. Lactic acid bacteria growth was strongly affected by the quantity and quality of nitrogen sources employed, while yeasts and fungi growth exceeded that obtained with the reference media commonly employed for their cultivation. Wasted bread medium (WBM) represents a realistic option for the valorization and re-use of bread waste, responding to the modern vision of circular economy.

Development of a new resource-saving technology of rye-wheat bread on liquid rye sourdoughs using recycled bread

“…The data on the sugar content showed that the slowing of acid-forming activity with an increase in the bread crumb dosage was not associated with a sugar deficiency, since the content of reducing sugars in the sourdough with bread crumbs was higher than in the control (Table 3). The high content of reducing sugars in sourdough with bread is confirmed by other studies [13,15,16]. When the amount of old bread increased up to 75%, the content of reducing sugars increased too.…”

“…The starch is in a gelatinized state, which makes it more accessible for the action of enzymes [8]. In this regard, white bread waste as a substrate for the production of baker's yeast and for the cultivation of starter cultures was investigated [9,10].…”

“…It is recommended to use old bread and defect bread in sourdoughs. Studies show that the use of recycled bread in the dough has a positive effect on the quality of the bread and the delay in staling [12][13][14][15][16].…”

“…Newly made bread may possess smell of old stale bread. Rapid bread microbial spoilage possible when spoiled bread (moldy, limy or ropy) was used [12][13][14][15][16]. Besides soaked bread is an excellent medium for microbial spoilage pathogens.…”

Recycling bread waste into chemical building blocks using a circular biorefining approach

“…For example, up to 40% of bread is lost in the sandwich-making process due to the removal of crusts from loaves. 6 Later the packed bread nds its way to retail stores or supermarkets through distributers. Storage and transport conditions play an essential role in maintaining the bread in a healthy environment to ensure high quality and a good lifespan.…”