Exergetic comparison of food waste valorization in industrial bread production

• Published in: Energy (Oxford) Vol. 82; pp. 640 - 649
• Main Authors: Zisopoulos, Filippos K., Moejes, Sanne N., Rossier-Miranda, Francisco J., van der Goot, Atze Jan, Boom, Remko M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.03.2015
• Subjects: Baking; Bread; Bread production; Consumption; Cooling; dryer; energy; Exergy; Food industry; Food waste; Foods; Recycling; Sustainability; sustainability assessment; Thermodynamics; transport; Wastes; Food waste; Recycling; Exergy; Sustainability; Food industry; Bread production
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2015.01.073

This study compares the thermodynamic performance of three industrial bread production chains: one that generates food waste, one that avoids food waste generation, and one that reworks food waste to produce new bread. The chemical exergy flows were found to be much larger than the physical exergy consumed in all the industrial bread chains studied. The par-baked brown bun production chain had the best thermodynamic performance because of the highest rational exergetic efficiency (71.2%), the lowest specific exergy losses (5.4 MJ/kg brown bun), and the almost lowest cumulative exergy losses (4768MJ/1000 kg of dough processed). However, recycling of bread waste is also exergetically efficient when the total fermented surplus is utilizable. Clearly, preventing material losses (i.e. utilizing raw materials maximally) improves the exergetic efficiency of industrial bread chains. In addition, most of the physical (non-material related) exergy losses occurred at the baking, cooling and freezing steps. Consequently, any additional improvement in industrial bread production should focus on the design of thermodynamically efficient baking and cooling processes, and on the use of technologies throughout the chain that consume the lowest possible physical exergy. •Preventing material losses is the best way to enhance the exergetic efficiency.•Most of the physical exergy losses occur at the baking, cooling and freezing steps.•Par-baking “saves” chemical exergy but consumes an equal amount of physical exergy.