An approach for valorising gas waste from bread production in bread shelf life extension

This study investigates the valorisation of ethanol (EtOH), 2-methyl-1-propanol (2MP), and 3-methyl-1-butanol (3 MB), which are released as gas waste during bread production, in bread preservation. The aim of this research is to explore the potential of these gases in improving bread preservation, thereby contributing to sustainability and waste reduction in the food industry. These compounds and their mixtures (ethanol, ethanol + 2MP, ethanol + 3 MB, ethanol + 2MP + 3 MB) were sprayed on bread slices, and their effects on the microbiological counts, colour, texture profile, moisture content, and sensory properties of bread slice samples were evaluated during storage for 21 days. Total mesophilic aerobic bacteria (TMAB) and yeast-mould counts of bread slices treated with the mixture of ethanol, 2MP, and 3 MB remained below 5 log cfu/g and 2 log cfu/g until days 14 and 17, respectively. However, the control samples exceeded these limits by day 8. In addition, while storage increased a* and b* values and decreased L* values, the application of using 2MP and 3 MB maintained the L* value of the bread slices. Moreover, storage increased the hardness and chewiness and decreased the cohesiveness and springiness of the samples. The bread slices treated with ethanol + 2MP and ethanol + 3 MB demonstrated lower hardness and chewiness than the control. Also, ethanol + 2MP + 3 MB provided the highest cohesiveness values. In addition, the samples with ethanol + 2MP and ethanol + 3 MB were softer and more elastic than the other samples as assessed by the sensory panel. Overall, it can be said that spraying a mixture of ethanol, 2MP, and 3 MB on bread slices was effective in shelf life extension. The use of ethanol + 2MP and ethanol + 3 MB mixtures was also advantageous in preserving the textural and sensory properties of bread slices.