Bread Waste Research Articles

Comprehensive techno-economic and environmental assessment for 2,3-butanediol production from bread waste

Bread waste (BW) is a common food waste in Europe and North America and has enormous potential as a biorefinery substrate for the sustainable synthesis of various platform chemicals. Our previous work made use of BW for the fermentative production of 2,3–butanediol (BDO). The present work evaluated the economic prospects and environmental consequences associated with the overall processes, handling 100 metric tons BW per day. The comprehensive process design using Aspen Plus and integrated techno-economic and environmental assessment was carried out for two different BW hydrolysis scenarios: acid and enzyme hydrolysis, followed by fermentation and extraction-based downstream BDO separation. The optimal heat exchanger network was designed using pinch analysis, which improved the energy efficiency of the process significantly, with about 10 % savings of BDO production costs. Despite this improvement, the BDO derived from BW was exorbitant (4.2–6.9 $/kg) compared to the market price (3.23 $/kg) due to relatively higher capital investment for the current plant capacity. Further, the process inventory was modelled in SimaPro v9.1.0 to estimate the environmental consequences of these production processes for impact categories, such as global warming (2.63 – 3.19 kg CO2 eq.), marine eutrophication (3.55 × 10-4 – 4.01 × 10-4 kg N eq.), terrestrial ecotoxicity (6.44 – 7.88 kg 1,4 − DCB), etc. Sensitivity and uncertainty analyses were also conducted to establish the reliability of the results. It was found that the enzyme hydrolysis was associated with lower environmental impacts than acid hydrolysis. This comprehensive study can be used as a guideline for developing sustainable BW-based biorefinery in the future.

Thermoplasticized Bread Waste and Poly(butylene adipate-co-terephthalate) Blends: A Sustainable Alternative to Starch in Eco-Friendly Packaging

Thermoplasticized Bread Waste and Poly(butylene adipate-<i>co</i>-terephthalate) Blends: A Sustainable Alternative to Starch in Eco-Friendly Packaging

What Remains in Students from an Etwinning Project: The Case of Şebit Project

The aim of this research is to find out how the eTwinning project prepared to prevent bread waste is evaluated from the students' perspective. The research was conducted within the scope of qualitative research. The research was carried out with 6th grade students consisting of six people who voluntarily participated in the eTwinning project. In line with the main purpose of the research, semi-structured interviews were conducted with the students at the end of the project and data were collected. The data obtained were subjected to content analysis, and codes and themes were created. At the end of the research, it was revealed that the students found the ŞEBİT eTwinning project educational, instructive and entertaining. In addition, it was determined that the project contributed to awareness of bread waste, learning web 2.0 tools, taking responsibility, teamwork and communication. In addition, it was determined that students had difficulties in using web 2.0 tools and time within the scope of the project. In line with the students' opinions, it is suggested that the eTwinning platform should be made more functional for both teachers and students within the scope of this research.

Restaurant food waste valorization by microwave-assisted hydrolysis: Optimization, typological and biochemical analysis

Annually, a substantial volume of food waste is being released into the environment. Restaurant food waste (RFW) valorization using microwave-assisted hydrolysis (MAH) is a sustainable approach to produce fermentable sugars. However, RFW is composed of different foodstuffs with different physicochemical, nutritional, and degradation rates. This study explored the typological, chemical, and elemental analysis of RFW. Results revealed that the four main types of RFW were vegetable (33.2 %), meat (19.3 %), rice (15.2 %), and bread waste (11.0 %). The key parameters impacting the MAH of typologically sorted RFW were identified using the Plackett–Burman design (PBD). Then the central composite design (CCD) with 30 runs was used to increase reducing sugar content (RSC). The optimized condition was as follows: temperature 96.0 °C, microwave power 340 W, HCl concentration of 1.45 %, and microwave heating time 11.1 min. The derived hydrolysates were characterized for their biochemical and monosaccharide composition.

Breaking bread: Assessment of household bread waste incidence and behavioural drivers

Bread, the most consumed floury product in the world, is one of the most wasted food products across the food supply chain. Yet, there is a paucity of research examining the magnitude of bread waste and behavioural drivers associated with it at the household level. This study analyses the incidence, behavioural drivers and disposal pathways of bread waste using a sample of 1462 households in Australia and a 7-day electronic diary method. Behavioural drivers related to bread waste were modelled using logistic regression models. The findings suggest that bread rolls, sliced bread and flat bread are the three most wasted bread products in Australian households. Higher grocery shopping frequency, ‘just-in-case’ buying, family households with young children and takeaway meal ordering are associated with higher bread waste. Bread disposal pathway analysis revealed that 55% of bread and bakery products are discarded through general waste bins, highlighting the immense potential of utilising bread waste in industrial processes such as biofuel production. Addressing bread and bakery waste can significantly contribute to achieving the SDG12.3 goal of halving the per capita food waste by 2030.

Development of hydrogels from cell wall of Aspergillus oryzae containing chitin-glucan and wet spinning to monofilaments

Fungal mycelium is emerging as a source for sustainable bio-based materials. Fungal biomass of Aspergillus oryzae was prepared by cultivation on bread waste hydrolysate to valorize this abundant food waste. Chitin-glucan-rich alkali-insoluble material (AIM) was isolated from fungal biomass, formed into hydrogels, and wet spun into monofilaments. AIM in the form of fungal microfibers containing 0.09 g polymer of glucosamine (GlcN)/g AIM was subjected to freeze–thaw and deacetylation treatments to increase the amount of GlcN. The GlcN fraction was 0.19 and 0.34 g polymer of GlcN/g AIM, for AIM subjected to deacetylation (AIM-DAC) and freeze–thaw cycles and deacetylation (AIM-FRTH-DAC), respectively. The increased GlcN fraction enabled the formation of hydrogels via the protonation of amino groups after the addition of lactic acid. Morphological differences in the hydrogels included aggregation of the fungal microfibers in the AIM-DAC hydrogel, whereas the microfibers in the AIM-FRTH-DAC hydrogel had a porous and interconnected network. Rheological assessment revealed shear thinning behavior and gel properties of the produced hydrogels. Wet spinning of the hydrogels resulted in monofilaments with tensile strengths of up to 70 MPa and 12 % elongation at break. This demonstrates promising avenues for biomaterial development from fungal cell walls containing chitin-glucan via food waste valorization.

Leftover bread as a potential feed additive: Impact on growth, fatty acid content, and antioxidant properties in Tenebrio molitor larvae

Bread waste in Saudi Arabia is a significant environmental issue that has caused significant losses. Insects, specifically Tenebrio molitor larvae, offer potential bioconversion solutions for food waste. Larvae were fed diets comprising different proportions of leftover bread (LB) powder mixed with wheat bran (WB), and feeding trials were conducted over 50 days. Results indicated that including LB powder did not significantly affect larval survival, affirming its safety. The larvae fed the diets LB100, LB75WB25, LB50WB50, LB25WB75, and WB reached the final weights of 27.64, 95.27, 105.012, 98.74, and 67.64 mg. Similarly, the highest mean pupal weight, at 0.133 mg, was observed when larvae were reared on LB75WB25, while the lowest mean pupal weight, at 0.107 mg, was recorded on the WB diet. Protein content varied significantly among diets, with mixed diets exhibiting protein content ranging from 16.98 % to 55.26 %. The primary fatty acid found in mealworm oil was oleic acid (C18:9), which made up 54.11 % of the total fatty acid content for larvae raised on 75LB:25WB, 52.01 % for LB, and 46.942 % for WB, with LB incorporation positively impacting growth, pupal weight, protein content, and antioxidant properties. Utilizing LB powder highlights its potential for sustainable insect farming, addressing environmental concerns, and enhancing resource sustainability.

Dry gel spinning of fungal hydrogels for the development of renewable yarns from food waste

BackgroundRenewable materials made using environmentally friendly processes are in high demand as a solution to reduce the pollution created by the fashion industry. In recent years, there has been a growing trend in research on renewable materials focused on bio-based materials derived from fungi.ResultsRecently, fungal cell wall material of a chitosan producing fungus has been wet spun to monofilaments. This paper presents a modification for the fungal monofilament spinning process, by the development of a benign method, dry gel spinning, to produce continuous monofilaments and twisted multifilament yarns, from fungal cell wall, that can be used in textile applications. The fungal biomass of Rhizopus delemar, grown using bread waste as a substrate, was subjected to alkali treatment with a dilute sodium hydroxide solution to isolate alkali-insoluble material (AIM), which mainly consists of the fungal cell wall. The treatment of AIM with dilute lactic acid resulted in hydrogel formation. The morphology of the hydrogels was pH dependent, and they exhibited shear thinning viscoelastic behavior. Dry gel spinning of the fungal hydrogels was first conducted using a simple lab-scale syringe pump to inject the hydrogels through a needle to form a monofilament, which was directly placed on a rotating receiver and left to dry at room temperature. The resulting monofilament was used to make twisted multifilament yarns. The process was then improved by incorporating a heated chamber for the quicker drying of the monofilaments (at 30⁰C). Finally, the spinning process was scaled up using a twin-screw microcompounder instead of the syringe pump. The monofilaments were several meters long and reached a tensile strength of 63 MPa with a % elongation at break of 14. When spinning was performed in the heated chamber, the tensile strength increased to 80 MPa and further increased to 103 MPa when a micro-compounder was used for spinning.ConclusionThe developed dry gel spinning method shows promising results in scalability and demonstrates the potential for renewable material production using fungi. This novel approach produces materials with mechanical properties comparable to those of conventional textile fibers.

Valorization of bread waste, a nonconventional feedstock for starch extraction using different methods: a comparative study

Valorization of bread waste, a nonconventional feedstock for starch extraction using different methods: a comparative study

Molecular changes and interactions of wheat flour biopolymers during bread-making: Implications to upcycle bread waste into bioplastics

This study aims to understand the molecular and supramolecular transformations of wheat endosperm biopolymers during bread-making, and their implications to fabricate self-standing films from stale white bread. A reduction in the Mw of amylopectin (51.8 × 106 vs 425.1 × 106 g/mol) and water extractable arabinoxylans WEAX (1.79 × 105 vs 7.63 × 105 g/mol), and a decrease in amylose length (245 vs 748 glucose units) was observed after bread-baking. The chain length distribution of amylopectin and the arabinose-to-xylose (A/X) ratio of WEAX remained unaffected during bread-making, suggesting that heat- or/and shear-induced chain scission is the mechanism responsible for molecular fragmentation. Bread-making also resulted in more insoluble cell wall residue, featured by water unextractable arabinoxylan of lower A/X and Mw, along with the formation of a gluten network. Flexible and transparent films with good light-blocking performance (<30 % transmittance) and DPPH-radical scavenging capacity (~8.5 %) were successfully developed from bread and flour. Bread films exhibited lower hygroscopicity, tensile strength (2.7 vs 8.5 MPa) and elastic modulus (67 vs 501 MPa) than flour films, while having a 6-fold higher elongation at break (10.0 vs 61.2 %). This study provides insights into the changes in wheat biopolymers during bread-making and sets a precedent for using stale bread as composite polymeric materials.

Innovative Fermented Beverages Based on Bread Waste—Fermentation Parameters and Antibacterial Properties

Faced with challenges related to environmental degradation and the growing need for sustainable development, the food sector must look for innovative and ecological production solutions. One of the increasingly popular directions is the zero-waste approach, which limits waste generation and enables its reuse. This research aimed to evaluate selected quality indicators of the lactic acid fermentation process of beverages based on waste from the bakery industry (wheat–rye bread) to determine the optimal fermentation conditions using two strains of lactic acid bacteria: Lacticasibacillus paracasei and Lactiplantibacillus plantarum. Preliminary process optimization was carried out, taking into account the beverage composition, fermentation time, and starting culture. The process evaluation and the selection of the optimal variant were based on the microbiological quality, pH value, and antimicrobial activity of fermented beverages. The results showed that the bread waste may constitute a base for obtaining fermented beverages as evidenced by the high number of lactic acid bacteria, above 108 CFU/mL, and low pH values (≤3.5) after the appropriate incubation time. Fermented beverages exhibited antibacterial properties against tested indicator microorganisms, which confirmed their functional properties. The analysis of the obtained results and the adopted assumptions enabled the selection of the most optimal variant—the beverage with ground flaxseed, fermented by L. paracasei for 24 h. The conducted research indicates great potential for lactic acid fermentation in the management of bakery waste to create innovative, sustainable food products with probiotic potential.

Protective Effects of Polysaccharides on Antifungal Activity of Bread Waste-derived Bioactive Peptides During Freeze Drying

Bioactive peptides (BPs) derived from agri-food side-streams display great potential as functional ingredients and nutraceuticals. However, BPs can be susceptible to environmental stressors and food processing conditions and typically exist as an aqueous mixture of various peptides, making their storage and use in foods very challenging. Microencapsulation offers a solution, utilizing suitable wall materials to create a protective matrix and transform them into powders for improved stability and application versatility. Here, we investigated the possibility of creating freeze-dried microencapsulated BP powders from bread waste using maltodextrin as the wall material to maintain their antifungal properties against Penicillum albocoremium, Eurotium herbariorum and Penicillium roqueforti fungi. The results were compared to those obtained from galactoglucomannans (GGM) and glucuronoxylans (GX) sourced from forest industry side-streams, aiming to explore their potential suitability as innovative materials for microencapsulating BPs. Maltodextrin microcapsules exhibited the highest inhibition rate on the tested fungi (10 − 44%), followed by GX (26 − 39%) and then GGM (9 − 14%) counterparts. Interactions between wall materials and BPs, as illustrated by FTIR analyses, were found to be the cause of variations in antifungal activities among BP microcapsules. The use of wall materials, especially wood hemicelluloses, facilitated freeze drying of BPs. However, their application in food products is restricted by the decline in the BP bioactivity resulting from the freeze drying process. For this reason, additional research on alternative drying methods is needed. The results of this study are expected to open new ways of production of stable functional ingredients from side-streams of the forest and food industries.

Antibacterial properties of oil extracts of black soldier fly larvae reared on bread waste

Context Farming black soldier fly larvae (BSFL) has become an emerging agricultural sector for upcycling food waste into high-quality protein and oil biomass. Depending on the chemical composition of the food waste, the oil extracted from BSFL can reach high levels of lauric acid, a natural antimicrobial compound. Aims We aimed to evaluate whether feeding a bakery waste-based substrate can enhance the lauric acid synthesis of BSFL. In addition, we aimed to test the antibacterial activity of these BSFL oil extracts against E. coli in vitro. Methods In a 12-day-long feeding trial, we reared BSFL either on a ground corn-based control substrate (n = 6) or a substrate based on bread waste sourced from a local bakery in Hong Kong (n = 6). We studied the growth performance, crude fat and lauric acid content, and agar well-diffusion assay-based antibacterial activity of oil samples extracted from the larvae. Key results The BSFL reared on the bread waste had a higher average weight (P &lt; 0.001) and average daily gain (P &lt; 0.001), similar crude fat content (P = 0.17), and higher lauric acid content (P &lt; 0.001) than did the control larvae. Both oil samples moderately inhibited the growth of E. coli in vitro; the inhibition zones were 1.92 ± 1.0 mm and 1.25 ± 0.75 mm (means ± s.d.) big in the bread waste-based and the control oil samples respectively (P = 0.28). Conclusions Our results indicated that locally sourced bread waste is a suitable substrate for farming BSFL, providing a sustainable alternative for waste management. Implications The inclusion of locally produced BSFL oil as a feed ingredient for the local livestock farming sector might be an avenue not only to achieve circular economy, but also to reduce antimicrobial drug use. However, the effects on animal health and productive performance warrant further in vivo experiments.

Valorisation of bread wastes via the bacterial cellulose production

AbstractThe short shelf life of bread can be attributed to changes in its textural and sensory properties, a process termed staling, and large amounts of bread residue and waste are generated daily. Because the main component of bread is starch, the use of bread wastes as a substrate for bacterial cellulose (BC) production can significantly contribute to valorisation and reuse of wastes. This study aimed to investigate the BC production potential of various stale breads, convert these wastes into usable forms for food and other industries, and increase their economic value. Stale breads were hydrolyzed with dilute acid, and BC-producing bacteria from Kombucha tea were isolated and identified as Gluconobacter oxydans MG2021 (GO). BCs were produced from bread hydrolysates with GO and Komagataeibacter hansenii GA2016 (KH), and their properties were examined. The results indicated that stale breads represented a good source for BC production, as high BC yields were obtained using GO (8.81%–25.02%) and all BCs had superior properties such as high crystallinity (75.96%–91.39%), thermal stability, liquid holding capacity, and fine fibers (40.16–85.39 nm). This study demonstrated that bread wastes could be used as a low-cost substrate for large-scale BC production, and the abundance of bread wastes demonstrated their potential as a resource for commercial BC producers.

Brewing Mainly from Stale Bread: A Pale Ale Case Study

Contemporary environmental concerns have led to the prioritization of sustainable production and material circularity, no matter what the industrial field of activity. Bread waste is a major element of overall food waste since, worldwide, bread remains a widespread staple food. A considerable proportion of bread consumption is of fresh, baked bread, consumed daily, generating substantial amounts of stale bread. Therefore, efforts to reintroduce this waste into the food value chain can make a significant contribution to reaching zero food waste, which is a major target in European countries. Possible ways to produce new raw materials through starch enzymatic hydrolysis include brewing, which is an activity in which incorporating stale bread is of great interest. Mashing parameters in brewing processing are the main focus of this study, primarily the time and temperature required to acquire optimal enzymatic activity for starch-efficient hydrolysis. Extending the mashing time to 290 min, within a temperature range of 45–75 °C, allowed us to replace 50% of the required malt with stale bread, thus obtaining a successful pale ale beer. The incorporation of stale bread in a 50:50 ratio did not affect the overall character of the beer, although the alcohol levels stood around 2% below a standard beer’s average level. Depending on the brewer’s final goal, this lighter kind of beer may be well-aligned with new consumer trends supporting more sustainable and lower-alcohol beverages.

Valorization of Bread Waste to Fungal-Based Products for Medical Textile and Food Applications

Valorization of Bread Waste to Fungal-Based Products for Medical Textile and Food Applications

Production Optimization, Partial Characterization, and Gluten-Digesting Ability of the Acidic Protease from Clavispora lusitaniae PC3

Protease-producing yeasts were isolated from potato wastes and screened for protease production on skim milk agar plates. The best producer of protease isolate was identified as Clavispora lusitaniae. The strain showed higher enzyme production using tomato pomace and bread waste mix as a solid fermentation substrate. The optimized conditions improved enzyme activity and showed a maximal production of 33,450 ± 503 IU/g compared with the initial activity of 11,205.78 ± 360 without medium optimization. A threefold increase in protease activity after medium optimization proved the reliability of using the PBD and CCD design. A 19.76-fold purified enzyme and a yield of 32.94% were obtained after purification. The protease showed maximum activity at pH 4 and 60 °C and was resistant to Tween 20, Tween 80, SDS, and β-mercaptoethanol, Ca2+, and Mg2+ stimulated it. The protease activity was strongly inhibited in the presence of urea, and EDTA. The results revealed Clavispora lusitaniae protease’s ability to degrade wheat seeds and flour gluten by 98.7% and 97% respectively under pH 4 for 24 h at 40 °C. According to this study, this enzyme could be a potential candidate for the food industry, particularly for treating wheat seed and flour to reduce the immunogenicity of gluten.

Bread waste valorization: a review of sustainability aspects and challenges

Bread waste (BW) poses a significant environmental and economic challenge in the United Kingdom (UK), where an estimated 20 million slices of bread are wasted daily. BW contains polysaccharides with great potential for its valorization into building block chemicals. While BW valorization holds tremendous promise, it is an emerging field with low technology readiness levels (TRLs), necessitating careful consideration of sustainability and commercial-scale utilization. This review offers a comprehensive assessment of the sustainability aspects of BW valorization, encompassing economic, environmental, and social factors. The primary objective of this review article is to enhance our understanding of the potential benefits and challenges associated with this approach. Incorporating circular bioeconomy principles into BW valorization is crucial for addressing global issues stemming from food waste and environmental degradation. The review investigates the role of BW-based biorefineries in promoting the circular bioeconomy concept. This study concludes by discussing the challenges and opportunities of BW valorization and waste reduction, along with proposing potential strategies to tackle these challenges.

Integrated biorefinery for bioethanol and succinic acid co-production from bread waste: Techno-economic feasibility and life cycle assessment

In this study, an advanced decarbonization approach is presented for an integrated biorefinery that co-produces bioethanol and succinic acid (SA) from bread waste (BW). The economic viability and the environmental performance of the proposed BW processing biorefinery is evaluated. Four distinctive scenarios were designed and analysed, focusing on a plant capacity that processes 100 metric tons (MT) of BW daily. These scenarios encompass: (1) the fermentation of BW into bioethanol, paired with heat and electricity co-generation from stillage, (2) an energy-optimized integration of Scenario 1 using pinch technology, (3) the co-production of bioethanol and SA by exclusively utilizing fermentative CO2, and (4) an advanced version of Scenario 3 that incorporates carbon capture (CC) from flue gas, amplifying SA production. Scenarios 3 and 4 were found to be economically more attractive with better environmental performance due to the co-production of SA. Particularly, Scenario 4 emerged as superior, showcasing a payback period of 2.2 years, a robust internal rate of return (33% after tax), a return on investment of 32%, and a remarkable net present value of 163 M$. Sensitivity analysis underscored the decisive influence of fixed capital investment and product pricing on economic outcomes. In terms of environmental impact, Scenario 4 outperformed other scenarios across all impact categories, where global warming potential, abiotic depletion (fossil fuels), and human toxicity potential were the most influential impact categories (−0.344 kg CO2-eq, −16.2 MJ, and −0.3 kg 1,4-dichlorobenzene (DB)-eq, respectively). Evidently, the integration of CC unit to flue gas in Scenario 4 substantially enhances both economic returns and environmental sustainability of the biorefinery.

Blood profiles of Etawa crossbreed goats fed concentrates substitution diet with bread waste

This study aims to determine the maximum level of the use of bread waste as a substitute for concentrates on feed utilization by livestock through blood profiles consisting of the amount of hemoglobin, erythrocyte numbers, hematocrit levels and leukocyte numbers. The material used in this study was 15 lactating Etawa crossbreed goats. The experimental design used was a randomized complete block design with 3 treatments and 5 replicates. The feed treatment given was forage and concentrate with a composition of 20:80 with ration treatments namely P1 = Silages 20% + Concentrates 64% + Bread waste 16% + Zeolite 2%, P2 = Silages 20% + Concentrates 56% + Bread waste 24% + Zeolite 2%, P3 = Silages 20% + Concentrates 48% + Bread waste 32% + Zeolite 2%. The observed variables were hemoglobin level (g/dL), erythrocyte count (million/μL), hematocrit level (%) and leukocyte count (thousand/μL). Data were analyzed using analysis of variance. The results showed that the treatment had no significant effect (P>0.05) on the blood profile which included hemoglobin levels, erythrocyte numbers, hematocrit levels and leukocyte numbers. Substitution of 24% bread flour in the ration gave the highest blood profile calculation results among the three treatments. The amount of Hemoglobin (g/dL) of P1, P2 and P3 were 8.88; 10.05 and 8.94. Erythrocyte numbers (million/μL). P1, P2 and P3 were 14.23; 15.92 and 14.59 respectively. Hematocrit levels (%) P1, P2 and P3 were 28.3; 30.98 and 28.72. Leukocyte numbers (thousand/μL) of P1, P2 and P3 were 13.68; 18.00 and 17.3. The conclusion of this study is that bread flour can be used as a substitute for concentrate up to 32% level in the ration and can maintain the blood profile of lactating Ettawa crossbreed goats in a normal state.