Browsing by Subject "Food waste"

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Comparative assessment of ethanol production from six typical German waste baked products
(2024) Almuhammad, Mervat; Kölling, Ralf; Einfalt, Daniel
This study investigates the potential for bioethanol production of six types of typical German leftover baked products: bread rolls, pretzel rolls, fine rye bread, white bread, pastry, and cream cakes. The experimental setup consisted of two experiments—one as a control and another with the addition of diammonium phosphate (DAP) to the mash. In terms of monosaccharide concentration at 30% dry matter (DM), white bread mash exhibited the highest level at 251.5 g/L, while cream cakes mash had the lowest at 186 g/L. The highest ethanol production occurred after 96 h of fermentation with rye bread, yielding 78.4 g/L. In contrast, despite having the highest monosaccharide levels, white bread produced only 21.5 g/L of ethanol after 96 h. The addition of DAP accelerated monosaccharide consumption in all baked products, with cream cakes completing the process in just 24 h. Bread rolls, pretzel rolls, pastry, and white bread fermentations finished within 72 h. Ethanol yields significantly increased in three DAP samples, with pretzel rolls yielding the highest ethanol concentration at 98.5 g/L, followed by white bread with 90.6 g/L, and bread rolls with 87.7 g/L. DAP had a substantial impact on all samples, reducing fermentation time and/or increasing ethanol yield. This effect was particularly pronounced with white bread, where it improved conversion efficiency from 17 to 72%, resulting in 90.6 g/L of ethanol. These results demonstrate that waste baked products hold substantial potential for bioethanol production, and this potential can be further enhanced through the addition of DAP.
Effect of liquefaction temperature and enzymatic treatment on bioethanol production from mixed waste baked products
(2025) Almuhammad, Mervat; Kölling, Ralf; Einfalt, Daniel
This study investigates the effect of different liquefaction temperatures (50–70 °C) and four commercial enzyme formulations on glucose release and subsequent ethanol yield, using mixed waste baked products as a substrate. Among the enzymes tested, Amylase GA 500 proved to be superior in the hydrolysis of starch at lower temperatures (50 °C and 55°C). At higher liquefaction temperatures (65 °C and 70°C) all four enzyme preparations showed comparable activity. The highest glucose concentration (205.7 g/L) and the highest ethanol yield (92 g/L) were achieved with Amylase GA 500 at 65 °C. Its superior performance is attributed to the synergistic activity of α-amylase and glucoamylase, which facilitates efficient starch hydrolysis. Crucially, we discovered that the liquefaction temperature profoundly affects fermentation speed independently of the initial glucose concentration or the enzyme preparation used for starch hydrolysis. This novel mechanistic insight suggests that higher temperature treatment either makes an additional factor crucial for yeast fermentation available or depletes/destroys an inhibitor present in the complex waste bakery product matrix. These findings highlight the critical role of temperature and enzyme formulation in optimizing bioethanol production from bakery waste, supporting the development of more sustainable and efficient waste-to-biofuel processes.
Obsoleszenz - auch ein Thema bei Lebensmitteln
Ergebnisse einer Expertenbefragung
(2018) Gebhardt, Beate; Ding, Jana-Lisa; Feisthauer, Philipp
Obsolescence is a topic that also concerns food products. Popular science has speculated that to a more or less significant extent, actors involved in food value chains were responsible for preliminary spoilage of food products. This speculation is true. Research and food experts in the field confirmed this during an expert survey conducted in 2015. This paper presents this survey. Experts confirm the main issue of this analysis which sheds light on the relevance of the following idea: Is obsolescence a topic regarding food products or does it only concern (technical) consumer goods? Only the latter is currently under debate. In total, 19 researchers and practicians from food value chains were surveyed and the majority shares this view. However, not all of them agree. The topic polarises researchers in particular. Eventually, issues such as the waste of ressources and social disparity due to food waste are not very disputed, irrespective of the reasons they emerged, but rather those responsible for the issue as well as the term that is to be used when food products spoil or are disposed preliminarily: obsolescence, food waste, avoidance, or other. The ensuing question focuses on this by addressing the advantages or added value if food waste was introduced into the debate on obsolescence or, on the contrary, if food waste was perceived in light of the debate on obsolescence. In this regard, we must emphasise the following key topics: 1) Avoiding arbitrary authority of definition: Shifting a term and generating authority of definition regarding (planned) obsolescence in merely specific areas is arbitrary. There are no objective reasons to apply obsolescence solely to consumer goods or technical devices. Irrespective of the type of industry, product, or the product’s shelf life, the reasons and circumstances for which products spoil preliminarily are similar in many aspects. Problems and reasons of unnecessary use of resources arise along the value chain due to processes and practices on all markets of modern and innovative societies. 2) Corrective of consumer responsibility: Addressing manufacturers and retailers represents a corrective when handing over responsibility for food waste. Especially in the food sector, to much responsibility is falling on consumers. In general, the aims of mitigating waste of resources are disputed. It should not pursue the way of least resistance and address primarily consumers. The corrective of consumer responsibility enables a corrective for solution-oriented approaches with greater diversity along the whole food value chain. 3) Problem-centred revision of definitions: In light of food waste, the use of natural materials and the role of agriculture are often neglected, described as inevitable, or excluded by definition or regulation (e.g. harvesting losses). However, obsolescence and its clear distinction between natural and artificial (planned) obsolescence does not fundamentally alter the view on natural resources of food and their use. Moreover, the necessity to critically revise regulation (e.g. the German Waste Management and Product Recycling Act) becomes clear. 4) Learning from and with each other: Changes in perspective and exchange among experts in debates on obsolescence and food waste are the bedrock to learn about tools, solutions, as well as experiences and mistakes made by others (e.g. proposal for a shelf life indication for technical devices without referring to experience with best-before indications of food products). Topics for further research include interdependencies and conflicts of targets which concern innovation for sustainability, shortage of product life cycles as well as the establishment of standards as means for more transparency to check their contribution to obsolescence and identify approaches for more appreciation in the overall concept considering all market participants.