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The issue of managing waste bread is a global concern, with significant environmental and the economic implications. The utilisation of waste bread for bioethanol production, employing energy-saving technology, could prevent these consequences and reduce the consumption of traditionally used fossil fuels. The objective of this study was to evaluate the influence of the type of waste bread (wheat and wheat–rye sourdough) and the mash preparation method on the results of alcoholic fermentation and the concentration of selected congeners in the distillates. The highest fermentation efficiency (96% of theoretical) was achieved for both types of bread through the utilisation of the pressureless starch liberation method combined with simultaneous saccharification and fermentation. The separate saccharification of starch resulted in lower process efficiencies (from 85.75 to 88.60% of theoretical). The application of the native starch hydrolysis method (without starch activation) for the fermentation of wheat bread-based mashes exhibited a higher efficiency (87.85% of the theoretical) than that observed for the wheat–rye bread-based mash sample (83.74% of theoretical). All of the obtained spirit distillates exhibited a low concentration of methanol (≤300 mg/L alcohol 100% v/v) and comply with the requirements of the EU regulation for ethyl alcohol of agricultural origin (rectified spirit).

A recent trend in sustainable bioethanol production is the use of agricultural waste or food waste as an inexpensive and the most available feedstock. Bread waste is the major food waste that could be successfully used for the production of bioethanol. The aim of this study was to optimize ethanol production by the response surface methodology (RSM) using waste bread hydrolysate. Waste bread hydrolysate was obtained using crude hydrolytic enzymes that produce bacterial isolate Hymenobacter sp. CKS3. The influence of time of fermentation (24–72 h) and waste brewer’s yeast inoculum (1–4 %) on ethanol production was studied. The optimal conditions, obtained by central composite design (CCD), were 48.6 h of fermentation and 2.85 % of inoculum. Under these conditions, a maximum of 2.06 % of ethanol concentration was reached. The obtained ethanol concentration was in good correlation, coefficient of 0.858, with yeast cell yield. The results obtained in this study imply that waste bread hydrolysate could be used as a biomass source for biofuel production with multiple benefits relating to environmental protection, reduction of production costs, and saving fossil fuels.

The increase in the wastage of bread, representing 12.5 million tons per year, causes ecological problems, such as the production of methane and CO2, when that waste bread (WB) is improperly managed. To reduce this ecological footprint, a more sustainable system of WB management must be set up. Based on its chemical composition, WB has a high potential to be used as feedstock for microbial growth and conversion into value-added bio products. The microbial valorisation of WB is a novel biotechnological approach to upgrading a waste into a renewable feedstock for bio-based industry, thus favouring the circular economy concept. Based on this, the aim of this study was to test WB as a feedstock for biomass production by Yarrowia lipolytica, which can be considered as a promising supplement for animal and human dietary products. The enzymatic hydrolysis of WB was primarily optimized for large-scale production in a bioreactor. The biomass production of Y. lipolytica strain K57 on WB hydrolysate-based media in batch bioreactor culture was then investigated. As a result, a very high starch to glucose conversion yield of 97% was obtained throughout optimised hydrolysis. At the end of 47 h of batch culture, a biomass higher than 62 g/L, specific growth rate of 0.37 h−1 and biomass yield of 0.45 g/g were achieved from a WB hydrolysate. Therefore, this study demonstrates that WB hydrolysate has a promising potential to be used as a feedstock for biomass production by Y. lipolytica strain K57 for food and animal diet applications.

Finding of optimal hydrolysis conditions is important for increasing the yield of saccharides. The higher yield of saccharides is usable for increase of the following fermentation effectivity. In this study optimal conditions (pH and temperature) for amylolytic enzymes were searched. As raw material was used waste bread. Two analytical methods for analysis were used. Efficiency and process of hydrolysis was analysed spectrophotometrically by Somogyi-Nelson method. Final yields of glucose were analysed by HPLC. As raw material was used waste bread from local cafe. Waste bread was pretreated by grinding into small particles. Hydrolysis was performed in 100 mL of 15 % (w/v) waste bread particles in the form of water suspension. Waste bread was hydrolysed by two commercial enzymes. For the liquefaction was used α‑amylase (BAN 240 L). The saccharification was performed by glucoamylase (AMG 300 L). Optimal conditions for α‑amylase (pH 6; 80 °C) were found. The yield of total sugars was 67.08 g∙L-1 (calculated to maltose). As optimal conditions for glucoamylase (pH 4.2; 60 °C) were found. Amount of glucose was 70.28 g∙L1. The time of waste bread liquefaction was 180 minutes. The time of saccharification was 90 minutes. The results were presented at the conference CECE Junior 2014.

The issue of managing waste bread is a global concern, with significant environmental and the economic implications. The utilisation of waste bread for bioethanol production, employing energy-saving technology, could prevent these consequences and reduce the consumption of traditionally used fossil fuels. The objective of this study was to evaluate the influence of the type of waste bread (wheat and wheat–rye sourdough) and the mash preparation method on the results of alcoholic fermentation and the concentration of selected congeners in the distillates. The highest fermentation efficiency (96% of theoretical) was achieved for both types of bread through the utilisation of the pressureless starch liberation method combined with simultaneous saccharification and fermentation. The separate saccharification of starch resulted in lower process efficiencies (from 85.75 to 88.60% of theoretical). The application of the native starch hydrolysis method (without starch activation) for the fermentation of wheat bread-based mashes exhibited a higher efficiency (87.85% of the theoretical) than that observed for the wheat–rye bread-based mash sample (83.74% of theoretical). All of the obtained spirit distillates exhibited a low concentration of methanol (≤300 mg/L alcohol 100% v/v) and comply with the requirements of the EU regulation for ethyl alcohol of agricultural origin (rectified spirit). [ABSTRACT FROM AUTHOR]

Background: Many species of sustainable mycotoxin-producing fungi are considered as dangerous agents for humans. Bread is one of the materials exposed to fungal infection and molds are amongst the most important pollutant microbial and chemical mycotoxin-producing agents of bread. In this study, the microbial and chemical contamination of recycled waste breads and the types of produced mycotoxins at two areas of Tehran municipality, Iran, were investigated. Methods: Using fungal culture media, twenty samples of waste bread were analyzed for microbial contaminations. To recognize contamination to mycotoxins, high-performance liquid chromatography (HPLC) method and fuorescence detector (FLD) were used. Findings: All but one sample were contaminated to mold infections such as Aspergillus, Penicillium, and yeasts including Geotricum candidum, Candidia albicans and Saccharomyces cerevisiae. Eight samples were contaminated to aflatoxins, ochratoxin A and deoxynivalenol, whereas none of them showed contamination with zearalenone. Conclusion: The results indicated that presence of microbial and toxic contamination in bread waste is inevitable, which is harmful for human health. The sanitary control of food waste to reduce or eliminate microbial hazards in food recycling is necessary.

In this paper yields of bioethanol from seven samples of bread were compared. Samples of bread were produced and prepared in a laboratory by mixing wheat and buckwheat flour in amounts of 0, 20, 40, 50, 60, 80 and 100%. At first, the analysis of all seven samples of bread was done (dry matter, starch content and pH value of bread sample suspensions). Then the waste bread suspensions were hydrolyzed by applying commercial hydrolytic enzymes, Termamyl® SC and SAN Extra® L. The fermentation process was carried out with dry instant yeast, Saccharomyces cerevisiae, after which distillation of all fermented suspensions was performed. The ethanol contents in the distillates of all seven samples were determined. The highest yield of bioethanol was detected in the bread sample made of pure wheat flour. The ethanol yield gradually decreased with increasing content of buckwheat flour in bread. These results could be useful when considering the possibility of utilization of waste bread from different sources as a feedstock for bioe­thanol production.

Sustainable biomass-based carbon aerogels have attracted extensive concerns in the area of energy storage and wearable sensory electronics. However, the pristine porosity and low weight of aerogels result in unsatisfactory mechanical and electrical properties, limiting their practical applications. Herein, activated porous carbon (APC), reduced graphene oxide (rGO) and carbon nanoparticles (CNP) are utilized as raw materials to develop a novel type of hierarchically waste bread-derived carbon aerogel via a stepwise activation/calcination strategy. The obtained bread-derived carbon aerogels, named APC-rGO/CNP, exhibits an outstanding electrical conductivity (∼3.23 S cm−1) and a high compressive modulus (∼124.60 MPa) by the synergistic bonding interactions. As a supercapacitor electrode, the APC-rGO/CNP composite manifests an excellent capacitance of 474.8 F g−1 (1.0 A g−1). Furthermore, an all-solid-state symmetric APC-rGO/CNP//APC-rGO/CNP supercapacitor with polyvinyl alcohol/potassium hydroxide (PVA/KOH) gel electrolyte realizes an energy density of 17.4 Wh kg−1 at 895 W kg−1. Notably, even under large compressive stress of 20 kPa, the supercapacitor still achieves a high energy density of 25.6 Wh kg−1 at a power density of 822.8 W kg−1, as well as an excellent capacitance retention of 93.8 % over 10,000 cycles. Finally, we demonstrate the potential of the APC-rGO/CNP composite as a responsive pressure sensor with an ultra-wide detecting span of 0–3 MPa and a moderate sensitivity of 0.22 kPa−1, which can detect keyboard pressing and fist clenching movements distinctively. Overall, the desirable mechanical performances and electrical conductivity of the APC-rGO/CNP composites facilitate the development of versatile nanomaterials to exploit state-of-the-art wearable electronics. • Waste bread-derived APC-rGO/CNP by a facile activation/calcination strategy. • Outstanding mechanical, conductive and capacitance properties of APC-rGO/CNP. • Superior properties of supercapacitor under deformation and long-term service. • APC-rGO/CNP pressure sensor with a wide detecting span and moderate sensitivity. [ABSTRACT FROM AUTHOR]

Food waste is a current global problem. The aim of this work was to investigate the possibility of reintroducing bread discarded by retailers in the preparation of sugar-snap cookies. Bread flours were obtained from stale breads (white and whole wheat) milled with 200, 500 and 1000 μm sieves. Cookies were elaborated using 100% bread flours and combinations of 50% of bread flour and wheat flour. The rheology of the doughs, the dimensions of the cookies, their texture and colour were evaluated. Bread flour doughs presented higher G’ (elastic modulus), G” (viscous modulus) values than the control, especially with increased particle size. Bread flour cookies had a smaller diameter and a harder texture than the control, but in the case of whole bread flours of larger particle sizes, those differences were reduced. Cookies made with bread flour had a darker colour and higher a* values. The 50% mixtures did not present significant differences with respect to the control in terms of dough rheology, hardness, or lightness. Although the spreading factor was reduced, it was more similar to the control than to 100% bread flour cookies. Wasted bread flour can thus be used to replace wheat flour in cookie formulations.

Food‐grade enzymes (α‐amylase, amyloglucosidase, maltogenic amylase, and protease) were investigated for recycling waste bread back to wheat bread‐making process. Waste bread was efficiently hydrolyzed into sugars (up to 93% glucose yield) and the best combination of enzymes was α‐amylase (0.05 g/kg bread) and amyloglucosidase (2.5 g/kg bread). Selected enzyme hydrolysis processes were tested in wheat bread making as a (a) hydrolyzed slurry, that is hydrolyzed waste bread without solid/liquid separation and (b) syrup, that is liquid supernatant after centrifugation of the hydrolyzed waste bread. Both hydrolyzed bread slurry and syrup were successfully utilized to replace sucrose (2 and 4%) in bread making without affecting the bread quality when compared to the control bread. Techno‐economic assessment revealed that this approach is 12% more economical than the current mean to dispose the bakery waste. This recycling concept showed both technical and economic potential for bakery industries to overcome their excess bread production. Novelty impact statement: A new recycling process was developed by using enzymes to efficiently hydrolyze surplus bread into sugars. The use of those sugar‐rich slurries and syrups in bread rework did not affect the bread quality when compared to the control bread. The recycling concept was more economical than current means to dispose waste bread, revealing the technical and economic potential for bakery industries to overcome their excess bread production. [ABSTRACT FROM AUTHOR]

According to the significant role of sugar alcohols (Polyols) in food industries, in the present study the possibility of microbial production of mannitol from bread waste was studied. Microbial growth and amylase production were investigated by five Iranian native strains of Bacillus spp in starch agar and broth. The best strain was selected, and its growth curve was determined. Leuconostoc mesentroides PTCC 1059 was used as a control strain to convert fructose to mannitol. In order to determine the ability of selected strains in converting waste breads into mannitol sugar, a culture medium was prepared from waste of Lavash and Baguette breads. Afterward, the ability to convert starch into fructose by Chemical analysis glucose test was used, and then bio-conversion analysis of fructose to mannitol by HPLC analysis was investigated. HPLC results showed that the Bacillus subtilis and Leuconostoc mesentroides PTCC 1059 had the ability of producing mannitol at a rate of 4.8g/L from fructose 5%, 0.15 g/L from Lavash bread 5%, and 0.2g/L from Baguette bread.