Brewers' spent grain: generation, characteristics and potential applications

Feasibility Analysis of Brewers’ Spent Grain for Energy Use: Waste and Experimental Pellets

Waste production is increasing every day as a consequence of human activities; thus, its valorization is becoming more important. For this purpose, the usage of wastes as biofuels is one of the most important aspects of sustainable strategies. This is the case of the main waste generated in brewing industries: brewers’ spent grain (BSG). In this sector, microbreweries are not able to properly manage the wastes that they generate due to lack of space. Consequently, the transformation of BSG to a high-quality biofuel might be an interesting option for this kind of small industry. In this work, we carried out a physical-energy characterization of BSG, as well as pellets from this waste. The initial characterization showed slightly unfavorable results concerning N and ash, with values of 3.76% and 3.37% db, respectively. Nevertheless, the physical characterization of the pellets was very good, with acceptable bulk density (662.96 kg·m−3 wb) and low heating value (LHV; 17.65 MJ·kg−1 wb), among others. This situation is very favorable for any of the intended uses (for energy use or animal feed, among others).

By-Products from Food Industry as a Promising Alternative for the Conventional Fillers for Wood-Polymer Composites

The present paper describes the application of two types of food-industry by-products, brewers' spent grain (BSG), and coffee silverskin (ŁK) as promising alternatives for the conventional beech wood flour (WF) for wood-polymer composites. The main goal was to investigate the impact of partial and complete WF substitution by BSG and ŁK on the processing, structure, physicochemical, mechanical, and thermal properties of resulting composites. Such modifications enabled significant enhancement of the melt flowability, which could noticeably increase the processing throughput. Replacement of WF with BSG and ŁK improved the ductility of composites, which affected their strength however. Such an effect was attributed to the differences in chemical composition of fillers, particularly the presence of proteins and lipids, which acted as plasticizers. Composites containing food-industry by-products were also characterized by the lower thermal stability compared to conventional WF. Nevertheless, the onset of decomposition exceeding 215 °C guarantees a safe processing window for polyethylene-based materials.

Insights into the Thermo-Mechanical Treatment of Brewers' Spent Grain as a Potential Filler for Polymer Composites

This paper investigated the impact of twin-screw extrusion parameters on the properties of brewers’ spent grain. The chemical structure, antioxidant activity, particle size, and color properties, as well as the emission of volatile organic compounds during extrusion, were investigated. The main compounds detected in the air during modifications were terpenes and terpenoids, such as α-pinene, camphene, 3-carene, limonene, or terpinene. They could be considered as a potential threat to human health and the environment. Changes in the chemical structure, antioxidant activity, and color of materials after modification indicated the Maillard reactions during extrusion, which resulted in the generation of melanoidins, especially at higher temperatures. This should be considered an exciting feature of this treatment method because modified brewers’ spent grain may improve the thermooxidative stability of polymer materials. Moreover, the impact of the brewers’ spent grain particle size on color and browning index used to determine the melanoidins content was investigated. The presented results show that proper adjustment of extrusion parameters enables the preparation of brewers’ spent grain with the desired appearance and chemical properties, which could maximize the efficiency of the modification process.

Mature Landfill Leachate as a Medium for Hydrodynamic Cavitation of Brewery Spent Grain

In this study, we evaluate the usefulness of mature landfill leachate (MLL) as a carrier allowing hydrodynamic cavitation (HD) of brewery spent grain (BSG). The HD experiments were conducted using an orifice plate with a conical concentric hole of 3/10 mm (inlet/outlet diameter) as a constriction in the cavitation device. The initial pressure was 7 bar and the number of recirculation passes through the cavitation zone reached 30. The results showed that complex organic matter was degraded and solubilized when cavitating the MLL and BSG mixture. The biochemical oxygen demand (BOD5) increased by 45% and the BOD5/total chemical oxygen demand (COD) ratio increased by 69%, whereas the COD, total solids, and nutrient concentration dropped noticeably. However, Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) revealed the generation of possibly toxic HD byproducts such as aromatic compounds. This seems to indicate that MLL could not be regarded as a suitable carrier for BSG cavitation.

Optimised Fractionation of Brewer’s Spent Grain for a Biorefinery Producing Sugars, Oligosaccharides, and Bioethanol

Brewer’s spent grain (BSG) is the main by-product of the beer brewing process. It has a huge potential as a feedstock for bio-based manufacturing processes to produce high-value bio-products, biofuels, and platform chemicals. For the valorisation of BSG in a biorefinery process, efficient fractionation and bio-conversion processes are required. The aim of our study was to develop a novel fractionation of BSG for the production of arabinose, arabino-xylooligomers, xylose, and bioethanol. A fractionation process including two-step acidic and enzymatic hydrolysis steps was investigated and optimised by a response surface methodology and a desirability function approach to fractionate the carbohydrate content of BSG. In the first acidic hydrolysis, high arabinose yield (76%) was achieved under the optimised conditions (90 °C, 1.85 w/w% sulphuric acid, 19.5 min) and an arabinose- and arabino-xylooligomer-rich supernatant was obtained. In the second acidic hydrolysis, the remaining xylan was solubilised (90% xylose yield) resulting in a xylose-rich hydrolysate. The last, enzymatic hydrolysis step resulted in a glucose-rich supernatant (46 g/L) under optimised conditions (15 w/w% solids loading, 0.04 g/g enzyme dosage). The glucose-rich fraction was successfully used for bioethanol production (72% ethanol yield by commercial baker’s yeast). The developed and optimised process offers an efficient way for the value-added utilisation of BSG. Based on the validated models, the amounts of the produced sugars, the composition of the sugar streams and solubilised oligo-saccharides are predictable and variable by changing the reaction conditions of the process.

Subcritical water as hydrolytic medium to recover and fractionate the protein fraction and phenolic compounds from craft brewer's spent grain

The valorization of the brewer's spent grain (BSG) generated in a craft beer industry was studied by subcritical water hydrolysis in a semi-continuous fixed-bed reactor. Temperature was varied from 125 to 185 °C at a constant flow rate of 4 mL/min. Biomass hydrolysis yielded a maximum of 78% of solubilized protein at 185 °C. Free amino acids presented a maximum level at 160 °C with a value of 55 mg free amino acids/g_protein-BSG. Polar amino acid presented a maximum at lower temperatures than non-polar amino acids. The maximum in total phenolic compounds was reached at 185 °C. This maximum is the same for aldehyde phenolic compounds such as vanillin, syringic and protocatechuic aldehyde; however, for hydroxycinnamic acids, such as ferulic acid and p-coumaric, the maximum was obtained at 160 °C. This allows a fractionation of the bioactive compounds. Subcritical water addresses opportunities for small breweries to be incorporated within the biorefinery concept.

Intensification of Xylo-oligosaccharides Production by Hydrothermal Treatment of Brewer's Spent Grains: The Use of Extremely Low Acid Catalyst for Reduction of Degradation Products Associated with High Solid Loading

Brewers' spent grains (BSG) make up to 85% of a brewery's solid waste, and is either sent to landfill or sold as cheap animal feed supplement. Xylo-oligosaccharides (XOS) obtained from BSG are antioxidants and prebiotics that can be used in food formulations as low-calorie sweeteners and texturisers. The effect of extremely low acid (ELA) catalysis in liquid hot water (LHW) hydrothermal treatment (HTT) was assessed using BSG with dry matter contents of 15% and 25%, achieved by dewatering using a screw press. Batch experiments at low acid loadings of 5, 12.5 and 20 mg/g dry mass and temperatures of 120, 150 and 170 °C significantly affected XOS yield at both levels of dry mass considered. Maximum XOS yields of 76.4% (16.6 g/l) and 65.5% (31.7 g/l) were achieved from raw BSG and screw pressed BSG respectively, both at 170 °C and using 5 mg acid/g dry mass, after 15 min and 5 min, respectively. These XOS yields were obtained with BSG containing up to 63% less water and temperatures more than 20 °C lower than that reported previously. The finding confirms that ELA dosing in LHW HTT allows lowering of the required temperature that can result in a reduction of degradation products, which is especially relevant under high solid conditions. This substantial XOS production intensification through higher solid loadings in HTT not only achieved high product yield, but also provided benefits such as increased product concentrations and decreased process heat requirements.

Sustainable valorisation pathways mitigating environmental pollution from brewers' spent grains

In this work, valorisation pathways of brewers' spent grains (BSG) towards biofuels production under the biorefinery concept were studied utilizing experimental data that provide a common base for straightforward comparison. The dehydration and the recovery of used oil, bioethanol and biogas from BSG were studied. The process units involved were thoroughly investigated and optimized. The oil extraction efficiency reached up to 70% using solid-liquid extraction process with hexane as solvent. The optimal ethanol yield achieved was 45% after the application of acid pretreatment, enzymatic hydrolysis with CellicCTec2 and fermentation with S. Cerevisiae. As far as biogas potential is concerned, the raw BSG, defatted BSG and stillage presented values equal to 379 ± 19, 235 ± 21 and 168 ± 39 mL biogas/g for respectively. Through the combination of the proposed schemes, three biorefinery scenarios were set up able to produce biodiesel, bioethanol and/or biogas. Material flow diagrams were set up in order to assess these schemes. Given that BSG could ensure 'green' energy production in the range of 4.5-7.0 million MJ/y if the European BSG potential is fully valorised, BSG could substantially contribute to the biofuel energy strategy.

Brewer's spent grain as a no-cost substrate for polyhydroxyalkanoates production: Assessment of pretreatment strategies and different bacterial strains

Polyhydroxyalkanoates (PHAs) are polyesters of significant interest due to their biodegradability and properties similar to petroleum-derived plastics, as well as the fact that they can be produced from renewable sources such as by-product streams. In this study, brewer's spent grain (BSG), the main by-product of the brewing industry, was subjected to a set of physicochemical pretreatments and their effect on the release of reducing sugars (RS) was evaluated. The RS obtained were used as a substrate for further PHA production in Burkholderia cepacia, Bacillus cereus, and Cupriavidus necator in liquid cultures. Although some pretreatments proved efficient in releasing RS (acid-thermal pretreatment up to 42.1 gRS L^-1 and 0.77 gRS g^-1 dried BSG), the generation of inhibitors in such scenarios likely affected PHA production compared with the process run without pretreatment (direct enzymatic hydrolysis of BSG). Thus, the maximum PHA accumulation from BSG hydrolysates was found in the reference case with 0.31 ± 0.02 g PHA per g cell dried weight, corresponding to 1.13 ± 0.06 g L^-1 and a PHA yield of 23 ± 1 mg g^-1 BSG. It was also found that C. necator presented the highest PHA accumulation of the tested strains followed closely by B. cepacia, reaching their maxima at 48 h. Although BSG has been used as a source for other bioproducts, these results show the potential of this by-product as a no-cost raw material for producing PHAs in a waste valorization and circular economy scheme.

Brewing By-Product Upcycling Potential: Nutritionally Valuable Compounds and Antioxidant Activity Evaluation

The brewing industry produces high quantities of solid and liquid waste, causing disposal issues. Brewing spent grains (BSGs) and brewing spent hop (BSH) are important by-products of the brewing industry and possess a high-value chemical composition. In this study, BSG and BSH, obtained from the production process of two different types of ale beer (Imperial red and Belgian strong beer) were characterized in terms of valuable components, including proteins, carbohydrates, fat, dietary fiber, β-glucans, arabinoxylans, polyphenols, and phenolic acids, and antioxidant activity (Ferric Reducing Antioxidant Power Assay (FRAP), 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS)). Significant concentrations of total polyphenols were observed in both BSH and BSG samples (average of about 10 mg GAE/g of dry mass); however, about 1.5-fold higher levels were detected in by-products of Belgian strong ale beer compared with Imperial red. Free and bound phenolic acids were quantified using a validated chromatographic method. A much higher level of total phenolic acids (TPA) (about 16-fold higher) was found in BSG samples compared with BSHs. Finally, their antioxidant potential was verified. By-products of Belgian strong ale beer, both BSG and BSH, showed significantly higher antioxidative capacity (about 1.5-fold lower inhibitory concentration (IC50) values) compared with spent grains and hop from the brewing of Imperial red ale. In summary, BSG and BSH may be considered rich sources of protein, carbohydrates, fiber, and antioxidant compounds (polyphenols), and have the potential to be upcycled by transformation into value-added products.

Brewers' spent grain as substrate for dextran biosynthesis by Leuconostoc pseudomesenteroides DSM20193 and Weissella confusa A16

Background

Lactic acid bacteria can synthesize dextran and oligosaccharides with different functionality, depending on the strain and fermentation conditions. As natural structure-forming agent, dextran has proven useful as food additive, improving the properties of several raw materials with poor technological quality, such as cereal by-products, fiber-and protein-rich matrices, enabling their use in food applications. In this study, we assessed dextran biosynthesis in situ during fermentation of brewers´ spent grain (BSG), the main by-product of beer brewing industry, with Leuconostoc pseudomesenteroides DSM20193 and Weissella confusa A16. The starters performance and the primary metabolites formed during 24 h of fermentation with and without 4% sucrose (w/w) were followed.

Results

The starters showed similar growth and acidification kinetics, but different sugar utilization, especially in presence of sucrose. Viscosity increase in fermented BSG containing sucrose occurred first after 10 h, and it kept increasing until 24 h concomitantly with dextran formation. Dextran content after 24 h was approximately 1% on the total weight of the BSG. Oligosaccharides with different degree of polymerization were formed together with dextran from 10 to 24 h. Three dextransucrase genes were identified in L. pseudomesenteroides DSM20193, one of which was significantly upregulated and remained active throughout the fermentation time. One dextransucrase gene was identified in W. confusa A16 also showing a typical induction profile, with highest upregulation at 10 h.

Conclusions

Selected lactic acid bacteria starters produced significant amount of dextran in brewers’ spent grain while forming oligosaccharides with different degree of polymerization. Putative dextransucrase genes identified in the starters showed a typical induction profile. Formation of dextran and oligosaccharides in BSG during lactic acid bacteria fermentation can be tailored to achieve specific technological properties of this raw material, contributing to its reintegration into the food chain.

Enzymatic hydrolysis using bacterial cultures as a novel method for obtaining antioxidant peptides from brewers' spent grain

Brewers' spent grain was used as a substrate to obtain protein hydrolysates with antioxidant activity. Hydrolysis was conducted in the culture using proteolytic bacteria. Hydrolysis was controlled by measurement of α-amino group concentration and with the aid of size exclusion chromatography. For each culture the degree of hydrolysis was calculated. The most efficient protein hydrolysis was observed in the cultures of Bacillus cereus (43.06%) and Bacillus lentus (41.81%). In addition, gelatin zymography was performed in order to detect bacterial proteases and their activity. The profile of secreted enzymes was heterogeneous, while the greatest variety was observed for Bacillus polymyxa. Brewers' spent grain protein hydrolysates exhibited high antioxidant activity. Bacillus subtilis and Bacillus cereus post-cultured media displayed the highest activity, respectively 1291.97 and 1621.31 μM TEAC per g for ABTS, 188.89 and 160.93 μM TEAC per g for DPPH, and 248.81 and 284.08 μM TEAC per g for the FRAP method.

Hydrolysis of brewers' spent grain conducted in the bacterial cultures entails reduction of workload, economic cost and environmental impact.

Potential of Brewer's Spent Grain as a Potential Replacement of Wood in pMDI, UF or MUF Bonded Particleboard

Brewer’s spent grain (BSG) is the richest by-product (85%) of the beer-brewing industry, that can be upcycled in a plentiful of applications, from animal feed, bioethanol production or for removal of heavy metals from wastewater. The aim of this research is to investigate the mechanical, physical and structural properties of particleboard manufactured with a mixture of wood particles and BSG gradually added/replacement in 10%, 30% and 50%, glued with polymeric diisocyanate (pMDI), urea-formaldehyde (UF) and melamine urea-formaldehyde (MUF) adhesives. The density, internal bond, modulus of rupture, modulus of elasticity, screw withdrawal resistance, thickness swelling and water absorption were tested. Furthermore, scanning electron microscopy anaylsis was carried out to analyze the structure of the panels after the internal bond test. Overall, it was shown that the adding of BSG decreases the mechanical performance of particleboard, due to reduction of the bonding between wood and BSG particles. This decrease has been associated with the structural differences proven by SEM inspection. Interaction of particles with the adhesive is different for boards containing BSG compared to those made from wood. Nevertheless, decrease in the mechanical properties was not critical for particleboards produced with 10% BSG which could be potentially classified as a P2 type, this means application in non-load-bearing panel for interior use in dry conditions, with high dimensional stability and stiffness.

Impact of sustainability and nutritional messaging on Italian consumers' purchase intent of cereal bars made with brewery spent grains

This work focuses on the reuse of brewery spent grains (BSGs), the most abundant by-product of the beer industry, today mainly used as animal feed. BSGs are rich in fibers and proteins as well as phenolic compounds, all of which are beneficial for human nutrition. Cereal bars containing 12% BSG were formulated and characterized instrumentally. Moreover, 159 panelists representative of young Italian consumers evaluated the bars in a central location test, along with a commercial cereal bar. Products were first evaluated blind, and then in an informed condition where additional product-specific nutritional and sustainability information was revealed, thus the purchase intent was determined. While the control product outperformed the BSG bar in most of the hedonic and sensory measures, the BSG sample was perceived as "natural/made with natural ingredients" by a significantly higher number of panelists (49%) compared to the control (30%). Additionally, even in the lower performing formulation, a significant positive effect on purchase intent was observed when providing either nutrition (fiber content) or sustainability (use of upcycled ingredients) information. The acceptable price range for the BSG and the commercial bar was very similar, whereas the optimal pricing point for the BSG was lower than the control. For the BSG product, sustainability information had significantly higher impact on purchase intent than nutrition-based information. Results highlight the importance of understanding consumer attitudes toward upcycling and the use of byproducts as ingredients in new food formulations. PRACTICAL APPLICATION: Results show how providing information on product nutrition and sustainability can increase purchase intent in the context of a cereal bar containing upcycled ingredients. The findings of this study can help food and consumer researchers to develop acceptable products that include BSG as an ingredient, potentially replacing other cereals in the recipe. The use of this brewery by-product could add value to the beer supply chain and to the final product as well, being also aligned with the current market trend of sustainability and functional health benefits.

Effects of additives in wet brewery residue silage on lamb carcass traits and meat quality

The objective was to evaluate the use of wet brewery residue (WBR) silage additives on carcass characteristics and sheep meat quality. Thirty-two Santa Inês male sheep uncastrated with initial body weight of 22.61 ± 7.2 kg were allocated to a completely randomized design with four treatments: (1) WBR silage without additive (WBRS), (2) WBR silage with milled corn (WBRS + MC), (3) WBR silage with wheat bran (WBRS + WB), and (4) WBR silage with cassava flour (WBRS + CF) and eight replicates. WBRS + WB resulted in lower cold carcass weight than WBRS + CF; however, this reduction was not sufficient to alter the carcass commercial yield or loin-eye area. The leg cut of animals fed WBRS + WB showed less value than those animals fed with WBRS + CS. The meat lightness of WBRS was higher that of WBRS + MC, WBRS + WB, and WBRS + CF. The cooking loss for WBRS + WB was less than those animals fed with WBRS + CS. However, meat protein, meat cholesterol, and shear force were similar among treatments (17.69%, 42.46 mg/100 g of meat, and 2.48 kgf/cm², respectively). The use of additives in wet brewery residue silage does not improve carcass characteristics or the quality of sheep meat, and it is therefore recommended to use WBR silage without additives.

Use Them for What They Are Good at: Mealworms in Circular Food Systems

Future food systems must provide more food produced on less land with fewer greenhouse gas emissions if the goal is to keep planetary boundaries within safe zones. The valorisation of agricultural and industrial by-products by insects is an increasingly investigated strategy, because it can help to address resource scarcities and related environmental issues. Thus, insects for food and feed have gained increasing attention as a sustainable protein production strategy in circular food systems lately. In this article, we provide an overview on by-products, which have already been fed to T. molitor (mealworms), a common edible insect species. In addition, we investigate other by-products in Austria, which can be suitable substrates for T. molitor farming. We also provide an overview and discuss different perspectives on T. molitor and link it with the circular economy concept. We identify several future research fields, such as more comprehensive feeding trials with other by-products, feeding trials with mealworms over several generations, and the development of a standardized framework for insect rearing trials. In addition, we argue that due to their ability to convert organic by-products from agricultural and industrial processes into biomass in an efficient way, T. molitor can contribute towards resource-efficient and circular food and feed production. However, several hurdles, such as legal frameworks, need to be adapted, and further research is needed to fully reap the benefits of mealworm farming.

The effect of brewery spent grain application on biogas yields and kinetics in co-digestion with sewage sludge

The present study examines the effect of introducing dried brewery spent grain (BSG), known as the main solid by-product of the brewery industry on biogas yields and kinetics in co-digestion with sewage sludge (SS). The experiment was conducted in semi-continuous anaerobic reactors (supplied once a day) operating under mesophilic conditions (35°C) at different hydraulic retention times (HRT) of 18 and 20 d. In co-digestion runs, the BSG mass to the feed volume ratio was constant and maintained 1:10.The results indicated that the addition of BSG did not influence the biogas production, by comparison with SS mono-digestion (control run). At HRT of 18 d, in the co-digestion run, the average methane yield was 0.27 m³ kg/VS_added, while in the control run the higher value of 0.29 m³ kg/VS_addedwas observed. However, there was no difference in terms of statistical significance. At HRT of 20 d, the methane yield was 0.21 m³ kg/VS_added for both mono- and co-digestion runs. In the BSG presence, the decrease in kinetic constant values was observed. As compared to SS mono-digestion, reductions by 21 and 35% were found at HRT of 20 and 18 d, respectively. However, due to the supplementation of the feedstock with BSG rich in organic compounds, the significantly enhanced energy profits were achieved with the highest value of approx. 40% and related to the longer HRT of 20 d. Importantly, the mono- and co-digestion process proceeded in stable manner. Therefore, the anaerobic co-digestion of SS and BSG might be considered as a cost-effective solution that could contribute to the energy self-efficiency of wastewater treatment plants (WWTPs) and sustainable waste management for breweries.

Effects of brewers' spent grain protein hydrolysates on gas production, ruminal fermentation characteristics, microbial protein synthesis and microbial community in an artificial rumen fed a high grain diet

BACKGROUND

Brewers' spent grain (BSG) typically contains 20% - 29% crude protein (CP) with high concentrations of glutamine, proline and hydrophobic and non-polar amino acid, making it an ideal material for producing value-added products like bioactive peptides which have antioxidant properties. For this study, protein was extracted from BSG, hydrolyzed with 1% alcalase and flavourzyme, with the generated protein hydrolysates (AlcH and FlaH) showing antioxidant activities. This study evaluated the effects of AlcH and FlaH on gas production, ruminal fermentation characteristics, nutrient disappearance, microbial protein synthesis and microbial community using an artificial rumen system (RUSITEC) fed a high-grain diet.

RESULTS

As compared to the control of grain only, supplementation of FlaH decreased (P < 0.01) disappearances of dry matter (DM), organic matter (OM), CP and starch, without affecting fibre disappearances; while AlcH had no effect on nutrient disappearance. Neither AlcH nor FlaH affected gas production or VFA profiles, however they increased (P < 0.01) NH3-N and decreased (P < 0.01) H2 production. Supplementation of FlaH decreased (P < 0.01) the percentage of CH4 in total gas and dissolved-CH4 (dCH4) in dissolved gas. Addition of monensin reduced (P < 0.01) disappearance of nutrients, improved fermentation efficiency and reduced CH4 and H2 emissions. Total microbial nitrogen production was decreased (P < 0.05) but the proportion of feed particle associated (FPA) bacteria was increased with FlaH and monensin supplementation. Numbers of OTUs and Shannon diversity indices of FPA microbial community were unaffected by AlcH and FlaH; whereas both indices were reduced (P < 0.05) by monensin. Taxonomic analysis revealed no effect of AlcH and FlaH on the relative abundance (RA) of bacteria at phylum level, whereas monensin reduced (P < 0.05) the RA of Firmicutes and Bacteroidetes and enhanced Proteobacteria. Supplementation of FlaH enhanced (P < 0.05) the RA of genus Prevotella, reduced Selenomonas, Shuttleworthia, Bifidobacterium and Dialister as compared to control; monensin reduced (P < 0.05) RA of genus Prevotella but enhaced Succinivibrio.

CONCLUSIONS

The supplementation of FlaH in high-grain diets may potentially protect CP and starch from ruminal degradation, without adversely affecting fibre degradation and VFA profiles. It also showed promising effects on reducing CH4 production by suppressing H2 production. Protein enzymatic hydrolysates from BSG using flavourzyme showed potential application to high value-added bio-products.

Use of barley malt pomace in the production of fresh sausage

Abstract The present study aimed to evaluate the effects of barley malt pomace addition on the characteristics of fresh pork sausages over 10 days of storage. Four fresh sausage formulations were elaborated, one with no addition of barley malt pomace (control formulation), and the other three elaborated with 3%, 6%, and 9% of pomace. The sausages were submitted to physicochemical analyses to determine ash, moisture, protein, lipid, carbohydrate, and raw fiber contents, water activity, pH, peroxide indices, and energetic value. Additionally, texture and color technological analysis and sensory analysis were performed. Sausages with 3% of malt pomace presented a protein content of 17.10% on the 10th day of storage, and raw fiber content of 2.00%; while in the control formulation these contents were 16.59% and 0.77%, respectively, with a significant difference (p ≤ 0.05) between samples, representing an increase in product nutritional value. In the hardness analysis, the control formulation had a value of 13.99 N and the formulation with 3% of pomace of 10.11 N, which shows that sausages with the addition of pomace are not as hard. In the sensory analysis, the control formulation showed about 80% acceptability in all attributes, the sausage with 3% of malt pomace had an acceptability index higher than 80% for the attribute 'global acceptance', the sausage with 6% of pomace had an index of approximately 70% and the formulation with 9% showed acceptability index of approximately 64% for the attribute 'global acceptance'. The addition of 3% of malt pomace to the sausage was the best alternative, since it had good acceptance by consumers, and provided an increased nutritional value. Our results show that the use of malt pomace in meat products is a viable alternative that helps to reduce production costs and aids in solving an environmental issue.

Tyrosinase inhibition by p-coumaric acid ethyl ester identified from camellia pollen

A tyrosinase inhibitor was separated from camellia pollen with the aid of solvent fraction, macroporous adsorptive resin chromatography, and high-speed countercurrent chromatography. The inhibitor was identified to be p-coumaric acid ethyl ester (p-CAEE) by nuclear magnetic resonance and mass spectrum. Its inhibitory activity (IC50 = 4.89 μg/ml) was about 10-fold stronger than arbutin (IC50 = 51.54 μg/ml). The p-CAEE inhibited tyrosinase in a noncompetitive model with the K I and K m of 1.83 μg/ml and 0.52 mM, respectively. Fluorescence spectroscopy analysis showed the p-CAEE quenched an intrinsic fluorescence tyrosinase. UV-Vis spectroscopy analysis showed the p-CAEE did not interact with copper ions of the enzyme. Docking simulation implied the p-CAEE induced a conformational change in the catalytic region and thus changed binding forces of L-tyrosine. Our findings suggest that p-CAEE plays an important role in inhibiting tyrosinase and provides a reference for developing pharmaceutical, cosmetic, and fruit preservation products using pollen.

Craft beer: An overview

The purpose of the work was to provide an overview on craft beer. Details and issues concerning history and legal definition market, fiscal policy, innovation, safety, healthiness, consumer profile, and sustainability are supplied. The term "craft brewery" generally refers to a brewery able to produce low volumes of beer, often made with traditional ingredients-for emulating historic styles-but also with the addition of nontraditional ingredients as a distinctiveness sign of the master brewer. In many countries, the importance of the company size is related to the opportunity to take advantage of reduced excise rates for low production volumes. In several countries, another important requisite of a craft brewery is represented by its independence from other alcohol industry members. Even in the presence of a great heterogeneity of the size of craft breweries in the various countries, their number in the world is around 17,000. Craft beer is mainly consumed in restaurants and bars. Innovation of craft beer concerns aspects, such as ingredients, alcohol content, aging, and packaging, and the profile of the typical craft beer drinker is that of a young man, with a higher education and a medium-high income. Craft beers are often not filtered/not pasteurized and, for these reasons, they are beverages rich in health compounds but with a reduced shelf life. As in the case of larger breweries, the environmental impact of craft breweries is mainly represented by water consumption and production of liquid and solid wastes.

Polyunsaturated fatty acids production by solid-state fermentation on polyurethane foam by Mortierella alpina

Polyunsaturated fatty acids (PUFAs) are essential in healthy diets and their production is extremely important. Natural sources of PUFAs includes animal and aquatic products such as marine fish oil, however there are several limitations such as the decrease of fish stocks throughout the world. Thus, microbial oils are a preferable source of PUFAs. Herein, it was studied the production of PUFAs by Mortierella alpina under solid-state fermentation (SSF) using polyurethane foam as inert substrate and synthetic medium or lignocellulosic hydrolysate as source of C, N, and other nutrients. Several parameters of fermentation conditions were evaluated as carbon source, inductors addition, ratio C/N and temperature. The highest amount of total PUFAs per mass of solid (535.41 ± 24.12 mg/g), linoleic acid (129.66 ± 5.84 mg/g), and α-linoleic acid (401.93 ± 18.10 mg/g) were produced when the culture medium contained 20 g/L glucose, 10% (w/v) linseed oil, the C/N ratio was adjusted to 25 and the incubation temperature was 25°C for 3 days decreasing to 16°C on the remaining 4 days of fermentation. In addition, a hemicellulosic hydrolysate can be used as low-cost substrate to produce PUFAs, although the production was lower than the achieved with synthetic medium. SSF showed an interesting technology for microbial PUFAs production.

Side-stream products of malting: a neglected source of phytochemicals

Whole grain consumption reduces the risk of several chronic diseases. A major contributor to the effect is the synergistic and additive effect of phytochemicals. Malting is an important technological method to process whole grains; the main product, malted grain, is used mainly for brewing, but the process also yields high amounts of side-stream products, such as rootlet. In this study, we comprehensively determined the phytochemical profile of barley, oats, rye, and wheat in different stages of malting and the subsequent extraction phases to assess the potential of malted products and side-streams as a dietary source of bioactive compounds. Utilizing semi-quantitative LC-MS metabolomics, we annotated 285 phytochemicals from the samples, belonging to more than 13 chemical classes. Malting significantly altered the levels of the compounds, many of which were highly increased in the rootlet. Whole grain cereals and the malting products were found to be a diverse and rich source of phytochemicals, highlighting the value of these whole foods as a staple. The characterization of phytochemicals from the 24 different sample types revealed previously unknown existence of some of the compound classes in certain species. The rootlet deserves more attention in human nutrition, rather than its current use mainly as feed, to benefit from its high content of bioactive components.

Poly(ε-Caprolactone)/Brewers’ Spent Grain Composites—The Impact of Filler Treatment on the Mechanical Performance

Waste lignocellulose materials, such as brewers’ spent grain, can be considered very promising sources of fillers for the manufacturing of natural fiber composites. Nevertheless, due to the chemical structure differences between polymer matrices and brewers’ spent grain, filler treatment should be included. The presented work aimed to investigate the impact of fillers’ reactive extrusion on the chemical structure and the poly(ε-caprolactone)/brewers’ spent grain composites’ mechanical performance. The chemical structure was analyzed by Fourier-transform infrared spectroscopy, while the mechanical performance of composites was assessed by static tensile tests and dynamic mechanical analysis. Depending on the filler pretreatment, composites with different mechanical properties were obtained. Nevertheless, the increase in pretreatment temperature resulted in the increased interface surface area of filler, which enhanced composites’ toughness. As a result, composites were able to withstand a higher amount of stress before failure. The mechanical tests also indicated a drop in the adhesion factor, pointing to enhanced interfacial interactions for higher pretreatment temperatures. The presented work showed that reactive extrusion could be considered an auspicious method for lignocellulose filler modification, which could be tailored to obtain composites with desired properties.

Technological Properties and Consumer Acceptability of Bakery Products Enriched with Brewers' Spent Grains

Nowadays, brewers’ spent grains (BSG) is considered the most abundant and low-cost brewing by-products, presenting a great potential as a functional food ingredient. Since BSG is rich in dietary fiber and protein, it can be a raw material of interest in bakery products. However, blending wheat flour with BSG can affect dough rheology and the structural and sensorial properties of products. In this context, BSG flour at different levels (0%, 5%, and 10%) was used to enrich three commercial soft wheat flours, and to develop new formulations for bakery products (bread, breadsticks and pizza). As expected, the enrichment caused a significant increase of proteins, dietary fibers, lipids, and ash related to the BSG enrichment level. Significant changes in dough rheological properties (e.g., higher water absorption, lower development time and stability, dough strength, and tenacity) and in the color of the crust and crumbs of bakery products were also observed. At last, the consumer test pointed out that the 5% BSG enrichment showed the higher overall acceptability of proposed bakery products.

Influence of the storage period on the nutritional and microbiological value of sun-dried brewer’s grains

Background: Brewer's grains, a by-product of the brewery industry, can be included in the diet of ruminants. However, its high humidity makes it difficult to store and preserve. Objective: To evaluate the efficiency of sun dehydration of wet brewer’s grains (WBG) and the effect of storage period on its nutritional and microbiological quality. Methods: A completely randomized experimental design was used to evaluate WBG dehydration efficiency, with treatments corresponding to 0, 1, 2, 4, 6, 8, 10, 12, 14 and 16 hours of sun exposure. A second experiment was carried out using also a completely randomized design to evaluated the effect of storage with the following treatments: 0, 10, 20, 30, 60, 90, 120, 150 and 180 days of storage of the dry by-product. Results: Dry matter (DM) content linearly increased with dehydration period. The chemical composition of the dried brewer's grains had no effect as a function of storage period. Indigestible protein (C fraction) increased linearly but did not compromise the cumulative gas production and the in vitro digestibility of DM and protein. Storage time had no effect on fungus population. The maximum aflatoxin value was 45.5 μg/kg, and remained within acceptable limits for bovine feed. Conclusion: Dehydration of WBG in the sun is efficient to guarantee conservation and makes it possible to store the by-product. The storage of the dry by-product for 180 days does not compromise its nutritional or microbiological quality.

Investigation of physicochemical, nutritional, and sensory qualities of muffins incorporated with dried brewer's spent grain flours as a source of dietary fiber and protein

Brewers' spent grain (BSG) is the major byproduct of brewing beer, rich in protein and dietary fiber. This study investigated the effect of two drying methods (impingement and hot-air drying) on chemical composition, physicochemical properties, and bioactive compounds of BSGs from three different brewers (BSG1, BSG2, and BSG3), and then evaluated the quality and consumer acceptance of BSG flour fortified muffins. Results showed that impingement drying led to significantly lower moisture content (MC, 1.33-1.87 g/100g) and water activity (a_w , 0.04-0.07) of BSGs than hot-air drying (5.44 to 5.57 g/100 g and 0.19 to 0.20, respectively). Among different dried BSGs, impingement dried BSG3 achieved the highest protein (18.03 g/100 g dry matter [DM]), total phenolic content (TPC, 2.21 mg GAE/g DM), radical scavenging activity (RSA, 1.58 mg AAE/g DM), and total flavonoid content (TFC, 0.68 mg QE/g DM), and retained lighter color (L*, 54.68) and higher total dietary fiber (TDF, 42.40 g/100 g DM), which was selected for making BSG-fortified muffins. BSG3 was substituted 1:1 as white: whole wheat flour at three concentrations (10, 15, and 20 g/100 g flour mix) for muffins (BSG10, BSG15, and BSG20, respectively). BSG15 provided higher protein (13.11 g/100 g DM), TDF (16.88 g/100 g DM), and higher bioactive compounds compared to control and retained brighter color of muffin compared to BSG20, showing no difference in firmness and overall liking compared to the control muffin. This study demonstrated that impingement dried BSG could be utilized as a functional ingredient in muffins to add value to the food chain providing nutritional and environmental benefits. PRACTICAL APPLICATION: This study reported the benefit of impingement drying method for the retention of physicochemical quality and bioactive compounds of brewer's spent grains (BSG) produced from three different brewers in comparison with hot-air drying. The study also reported that muffins fortified with BSG flours (15% replacement of wheat flour) yielded a 23% increase in total dietary fiber and 13% increase in protein without affecting consumer acceptance of the products. This information is essential for developing value-added applications of BSG, a byproduct from brewing industry, as a functional ingredient to make nutritive baking goods, such as muffins, for promoting human health.

Supplementary value of ensiled brewers spent grain used as replacement to cotton seed cake in the concentrate diet of lactating crossbred dairy cows

The aim of this study was to investigate the effects of ensiled brewers spent grain (BSG) when used as replacement to cotton seed cake in the concentrate diet of lactating crossbred dairy cows. Eight early lactating F1 Boran X Friesian cows were used in a short term feeding trial to identify optimum level of ensiled BSG substitution of cotton seed cake (0, 33, 66, and 100%) in iso-nitrogenous diets. A 4 × 4 double Latin square design was used to analyze the data set generated from the feeding and digestibility trials. The results showed that as the level of ensiled BSG replacement to cotton seed cake increased, daily intakes on the natural pasture hay: 8.1 (T1) vs 7.6 (T2), 6.0 (T3), and 5.1 (T4); total feed dry matter: 14.6 (T1) vs 14.0 (T2), 12.9 (T3), and 12.2 (T4); crude protein (CP): 2.0 (T1) vs 1.9 (T2), 1.8 (T3), and 1.7 (T4); neutral detergent fiber (NDF): 8.4 (T1) vs 8.2 (T2), 7.4 (T3), and 6.8 (T4); and acid detergent fiber (ADF): 4.8 (T1) vs 4.5 (T2), 3.8 (T3), and 3.3 (T4) decreased (P < 0.05). However, estimated metabolizable energy (EME) intakes (129 vs 126) and body weight of the animals (465 vs 467) on the control diet and dietary T2 (33% BSG replacement for cottonseed cake) were comparable (P > 0.05). Thereafter, differences in daily EME intakes and body weight changes decreased with an increase in the level of ensiled BSG in the concentrate diet (P < 0.05) compared with both the control and animals on T2. Ensiled BSG, on the other hand, substantially improved (P < 0.05) total ration's apparent digestibility of dry matter (DM): 629 (T1) vs 659 (T3), 686 (T4); CP: 676(T1) vs 690(T3), 738(T4); NDF: 524 (T1) vs 544 (T3), 581 (T4); and ADF: 341 (T1) vs 350 (T2), 392 (T3), 440(T4) and daily milk yield: 14.5 (T1) vs 15.4 (T4) and milk production efficiency: 0.98 (T1) vs 1.11 (T3) and 1.26 (T4). So, ensiled BSG can be recommended to fully replace cotton seed cake from the concentrate diet of lactating dairy cows under local conditions. Additional research is needed to minimize and/or avoid body weight loss, milk fat, and total solids.

The role of microorganisms on biotransformation of brewers' spent grain

Brewers' spent grain (BSG) is the most abundant by-product of brewing. Due to its microbiological instability and high perishability, fresh BSG is currently disposed of as low-cost cattle feed. However, BSG is an appealing source of nutrients to obtain products with high added value through microbial-based transformation. As such, BSG could become a potential source of income for the brewery itself. While recent studies have covered the relevance of BSG chemical composition in detail, this review aims to underline the importance of microorganisms from the stabilization/contamination of fresh BSG to its biotechnological exploitation. Indeed, the evaluation of BSG-associated microorganisms, which include yeast, fungi, and bacteria, can allow their safe use and the best methods for their exploitation. This bibliographical examination is particularly focused on the role of microorganisms in BSG exploitation to (1) produce enzymes and metabolites of industrial interest, (2) supplement human and animal diets, and (3) improve soil fertility. Emerging safety issues in the use of BSG as a food and feed additive is also considered, particularly considering the presence of mycotoxins.Key points• Microorganisms are used to enhance brewers' spent grain nutritional value.• Knowledge of brewers' spent grain microbiota allows the reduction of health risks. Graphical abstract.

In Vitro Evaluation of Enriched Brewers' Spent Grains Using Bacillus subtilis WX-17 as Potential Functional Food Ingredients

Brewers' spent grains (BSGs) are nutritious food processing by-products generated in the brewing industry. In this study, in vitro digestion-fermentation was employed to examine fermented BSG using Bacillus subtilis WX-17 as functional food ingredients. Insoluble fibers in BSG were converted into soluble fibers after fermentation, giving an increase from 6.13 ± 0.42 to 9.37 ± 0.53 mg/100 g BSG. After in vitro digestion of unfermented and fermented BSG, various nutritional components were found to be higher in fermented BSG. Components such as amino acids and fatty acids gave a concentration of 1.635 ± 0.236 mg/mL and 6.35 ± 0.65 mg/mL, respectively. Additionally, vitamin K₂ MK7 was detected in fermented BSG with a concentration of 0.00012 ± 0.000005 mg/mL. Probiotics Bacillus subtilis WX-17 was observed to withstand the in vitro digestion. After in vitro fermentation, various short-chain fatty acids namely acetic acid, propanoic acid, and butyric acid were produced at higher amounts for fermented BSG. The concentrations obtained were 124.11 ± 18.72 mM, 13.18 ± 1.38 mM, and 46.25 ± 7.57 mM respectively. As for gut microbiota profile, differential genera such as Bacteroides and Ruminococcus were detected, showing different effects on the intestinal microbiota. This study demonstrates the potential of using microbial fermentation of underutilized BSG to serve as potential functional food ingredients.

Physicochemical Characterization and SEM-EDX Analysis of Brewer’s Spent Grain from the Craft Brewery Industry

The brewing industry generates, as the primary coproduct, brewers’ spent grain (BSG). In Mexicali, Baja California, Mexico, there are 17 companies that generated 282 tons of BSG by 2016. Cattle feeding is the most common type of disposal for this waste. However, it can be valorized for the production of bioenergy or as a source of added-value products. Therefore, the objective of the present work was to assess the physicochemical properties of the brewers’ spent grain from a local craft brewery, to choose the most appropriate exploitation route. Chemical and morphological analyses were carried out by energy dispersive X-ray fluorescence spectroscopy (EDX), scanning electron microscopy, and the higher heating value determination. The results of the proximate analyses were 72.32% moisture, 78.47% volatile matter, 17.48% fixed carbon, and 4.05% ash. The results of the chemical analysis for extractables were 5.23% using organic solvent and 50.25% using hot water. The content determination were 17.13% lignin, 26.80% cellulose, and 37.17% hemicellulose. The results of the ultimate analysis were 43.59% C, 6.18% H, 3.46% N, and 37.22% O. The higher heating value experimentally obtained was 18.70 MJ/kg. Moreover, in the EDX analysis, Ca, P, K, and S were mainly found. It is recommendable to valorize the BSG through the xylitol, bioethanol or biogas production, because of its high moisture, hemicellulose and cellulose content.

Ultrasound processing of coffee silver skin, brewer's spent grain and potato peel wastes for phenolic compounds and amino acids: a comparative study

Awareness towards utilizing food-processing by-products are increasing in health as well as environmental purview. Coffee silver skin (CSS), potato peel (PP) and brewer's spent grain (BSG) are voluminous by-products in their respective processing industries. The present study compared these three by-products for their prospective utilization in producing polyphenols-rich aqueous extracts by using ultrasound-assisted extractions (UAE). A probe-type sonicator was used for ultrasound treatments. The total phenolic contents in the extracts were assessed by Folin-Ciocalteu assay, while the phenolic profiles of the extract was characterized by LC-Q-TOF mass spectrometry. The microstructure of the samples after UAE was evaluated by scanning electron microscopy (SEM). Ultrasound treatment enhanced the rate of extraction and recovered 2.79, 2.12 and 0.66 mg gallic acid equivalents/g of TPC from CSS, PP and BSG, respectively in 30 min, which correspond to recoveries of 97.6%, 84.5% and 84.6%, respectively, compared to conventional solid-liquid extractions carried out for 24 h. The extraction yield was dependent on the particle size of the raw materials and the highest yield was obtained from the materials with 100-250 µm particle size. The SEM imaging revealed that ultrasound treatment caused prominent tissue damage. Extracts contained mainly hydroxycinnamic acid derivatives of phenolic acids. PP and CSS had the highest amounts of umami free amino acids (0.13 mg/g in each), while BSG contained the highest amount of essential amino acids (92 mg/g). The present work shows that CSS, PP and BSG are good sources of polyphenols and UAE can be employed to enhance the extraction efficiency as means of a green approach.

Brewer’s Spent Grains: Possibilities of Valorization, a Review

This review was based on updated research on how to use brewer’s spent grains (BSG). The use of BSG was considered both in food, as an ingredient or using value-added components derived from brewer’s spent grain, or in non-food products such as pharmaceuticals, cosmetics, construction, or food packaging. BSG is a valuable source of individual components due to its high nutritional value and low cost that is worth exploiting more to reduce food waste but also to improve human health and the environment. From the bioeconomy point of view, biological resources are transformed into bioenergetically viable and economically valuable products. The pretreatment stage of BSG biomass plays an important role in the efficiency of the extraction process and the yield obtained. The pretreatments presented in this review are both conventional and modern extraction methods, such as solvent extractions or microwave-assisted extractions, ultrasonic-assisted extractions, etc.

By-Products in the Malting and Brewing Industries—Re-Usage Possibilities

Beer production includes the formation of different by-products such as wastewater, spent grains, spent hops, and yeast. In addition to these well-known by-products, it is necessary to mention germ/rootlets, which also remain after the malting process. Given that a huge amount of beer is produced annually worldwide, by-products are available in large quantities throughout the year. Spent grains, spent hops, and spent yeasts are high-energy raw materials that possess a great potential for application in the branch of biotechnology, and the food industry, but these by-products are commonly used as livestock feed, disposed of in the fields, or incinerated. Breweries by-products can be utilized for microalgae production, biofuel production, extraction of proteins, polyphenolic, antioxidative substances, etc. This paper aims to address each of these by-products with an emphasis on their possible application in biotechnology and other industries.

Simultaneous production of mesoporous biochar and palmitic acid by pyrolysis of brewing industry wastes

Pyrolysis of malt bagasse was carried out to obtain simultaneously a mesoporous biochar and an oil fraction rich in palmitic acid. The best result for biochar production was at 500 °C with holding time of 10 min. The yields of biochar and pyrolytic oil in this condition were, 29.7 and 33.9 wt%, respectively. The pyrolysis temperature and holding time influenced the yields of the products. An increase in pyrolysis temperature (from 500 to 700 °C) and holding time (from 10 to 50 min) caused a decrease in biochar yield, a reduction in the volatile matter content and an increase in the amount of ash. Additionally, in the range studied in this work, the increase of the pyrolysis temperature caused a decrease in the specific surface area and total pore volume of the biochar. Meanwhile, the biochar presented interesting functional groups and a mesoporous character, which can be a precursor to obtain adsorbents, or even, be used as adsorbent. The pyrolytic oil was composed of oxygenated aromatic compounds, the main fraction being palmitic acid (27.3%), which can be used in a number of applications, including biodiesel production. This work demonstrated that an available and problematic waste, malt bagasse, can be converted simultaneously into a mesoporous biochar and, into a pyrolytic oil rich in palmitic acid. Biochar and pyrolytic oil, in turn, are products of great value and can be applied in several fields.

Utilization of brewery wastes in food industry

Beer is the most popular low-alcohol beverage consumed in large amounts in many countries each year. The brewing industry is an important global business with huge annual revenues. It is profitable and important for the economies of many countries around the world. The brewing process involves several steps, which lead to fermentation of sugars contained in malt and conversion thereof into alcohol and carbon dioxide by yeasts. Beer brewing generates substantial amounts of by-products. The three main brewing industry wastes include brewer's spent grain, hot trub, and residual brewer's yeast. Proper management of these wastes may bring economical benefits and help to protect the environment from pollution caused by their excessive accumulation. The disposal of these wastes is cumbersome for the producers, however they are suitable for reuse in the food industry. Given their composition, they can serve as a low-cost and highly nutritional source of feed and food additives. They also have a potential to be a cheap material for extraction of compounds valuable for the food industry and a component of media used in biotechnological processes aimed at production of compounds and enzymes relevant for the food industry.

Simple and Sustainable Preparation of Nonactivated Porous Carbon from Brewing Waste for High-Performance Lithium-Sulfur Batteries

The development of renewable energy sources requires the parallel development of sustainable energy storage systems because of its noncontinuous production. Even the most-used battery on the planet, the lithium-ion battery, is reaching its technological limit. In light of this, lithium-sulfur batteries have emerged as one of the most promising technologies to address this problem. The use of biomass to produce cathodes for these batteries addresses not only the aforementioned problem, but it also reduces the carbon footprint and gives added value to something normally considered waste. Here, the production, by simple and nonactivating pyrolysis, of a carbon material using the abundant "after-boiling waste" derived from beer brewing is reported. After adding a high sulfur loading (70 %) to this biowaste-derived carbon by the "melt diffusion" method, the sulfur-carbon composite is used as an effective cathode in Li-S batteries. The cathode shows excellent performance, reaching high capacity values with long-term cyclability at high current-847 mAh g^-1 at 1 C, 586 mAh g^-1 at 2 C, and even 498 mAh g^-1 at 5 C after 400 cycles-drastically reducing capacity loss to values approaching 0.01 % per cycle. This work demonstrates the possibility of obtaining low-cost, highly sustainable cathodic materials for the design of advanced energy storage systems.

Lipid profile and growth of black soldier flies (Hermetia illucens, Stratiomyidae) reared on by-products from different food chains

BACKGROUND

The total amount of bio-waste produced annually in the EU by the food and beverage chains is estimated at 37 billion kg. The use of insects for the valorization of by-products from these value chains may represent a sustainable solution. This study aimed to investigate the by-products obtained from different food chains and used for the rearing of black soldier fly (BSF) prepupae, and to evaluate the content and profile of the lipid extracted from the prepupae and outline its possible applications. The substrates used in this experiment were: (i) industrial by-products (brewery spent grains, cows' milk whey, grape stalks, and tomato peels and seeds) and (ii) by-products from retailers (bread dough, fish scraps, and spent coffee ground). Fat extracted from prepupae using an adjusted Folch method was used for total lipid content and fatty acid profile.

RESULTS

The best larval performances were obtained from beer (0.22 g_weight per prepupa), tomato (0.19 g_weight per prepupa), and cheese (0.14 g_weight per prepupa) food-chain by-products. The extremely different compositions of the substrates were reflected in the differentiated lipid profile of the BSF prepupae and in the range of ratios between unsaturated and saturated fatty acids, which varied from 0.37 for cows' milk whey to 1.34 for tomato peels and seeds.

CONCLUSION

The lipids, proteins, and chitin extracted from prepupae are high-value bio-based products that could be used in the feed / food industry or for the development of innovative biomaterials, such as biodiesel. These results suggest that food-chain by-products are the best candidates for insect-bioconversion purposes. © 2020 Society of Chemical Industry.

Phytochemical Composition of Brewers’ Spent Grains

Brewers’ spent grains (BSG) are the main waste product of the brewing industry, accounting for about 85% of the total waste materials. Their composition is different (due to various brewing technologies) but includes high levels of dietary fiber, proteins, essential amino acids, polyphenols, antioxidants, vitamins and fats. The aim of the present study was to investigate the phenolic content and antioxidant activity (the radical scavenging assay (DPPH) and ferric reducing antioxidant power (FRAP)) of 19 different malt types and their BSG. The highest phenolic content was demonstrated by the BSG of Caraaroma malt, whereas the BSG of Carafa Special type 1 had the highest DPPH radical scavenging activity and ferric reducing antioxidant power. Based on the results obtained, malts with the highest biological value were selected for inclusion in the composition of functional foods.

Environmental impact of lignocellulosic wastes and their effective exploitation as smart carriers - A drive towards greener and eco-friendlier biocatalytic systems

In recent years, lignocellulosic wastes have gathered much attention due to increasing economic, social, environmental apprehensions, global climate change and depleted fossil fuel reserves. The unsuitable management of lignocellulosic materials and related organic wastes poses serious environmental burden and causes pollution. On the other hand, lignocellulosic wastes hold significant economic potential and can be employed as promising catalytic supports because of impressing traits such as surface area, porous structure, and occurrence of many chemical moieties (i.e., carboxyl, amino, thiol, hydroxyl, and phosphate groups). In the current literature, scarce information is available on this important and highly valuable aspect of lignocellulosic wastes as smart carriers for immobilization. Thus, to fulfill this literature gap, herein, an effort has been made to signify the value generation aspects of lignocellulosic wastes. Literature assessment spotlighted that all these waste materials display high potential for immobilizing enzyme because of their low cost, bio-renewable, and sustainable nature. Enzyme immobilization has gained recognition as a highly useful technology to improve enzyme properties such as catalytic stability, performance, and repeatability. The application of carrier-supported biocatalysts has been a theme of considerable research, for the past three decades, in the bio-catalysis field. Nonetheless, the type of support matrix plays a key role in the immobilization process due to its influential impact on the physicochemical characteristics of the as-synthesized biocatalytic system. In the past, an array of various organic, inorganic, and composite materials has been used as carriers to formulate efficient and stable biocatalysts. This review is envisioned to provide recent progress and development on the use of different agricultural wastes (such as coconut fiber, sugarcane bagasse, corn and rice wastes, and Brewers' spent grain) as support materials for enzyme immobilization. In summary, the effective utilization of lignocellulosic wastes to develop multi-functional biocatalysts is not only economical but also reduce environmental problems of unsuitable management of organic wastes and drive up the application of biocatalytic technology in the industry.

Technology innovations for food security in Singapore: A case study of future food systems for an increasingly natural resource-scarce world

Background

Food security is becoming an increasingly important global issue. Anthropogenic factors such as rapid urbanization and industrialization have strained finite resources like land and water. Therefore, against the impending threat of food security, the world can no longer rely on traditional methods to meet its needs. Instead, more creative and technologically advanced methods must be adopted to maximise diminishing natural resources. Singapore is a good case study of a small city-state that is trying to increase its own self-production of food using technology.

Scope and approach

This review highlights the technologies that Singapore have adopted in enhancing food security given its limitation in natural resources. These methodologies serve as a case study that can be used as a reference point in light of the increasingly finite natural resources. The review also presents the advantages of these techniques as well as challenges that need to be overcome for them to be more widely adopted.

Key findings and conclusion

To increase self-production of food and enhance its food security, Singapore has employed the use of technologies such as vertical farming and aquaponics in urban farming, nutrient recovery from food waste, biodegradable food packaging from durian rinds, natural preservatives, insect farming, microalgae and cultivated meat as alternative protein sources. These technologies workaround Singapore's land and natural resource constraints, which many countries around the world can adapt. However, many of them are still relatively nascent with numerous challenges, which have to be addressed before they can be widely accepted and implemented.

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Long term agriculture and pollution have led to depletion of natural resources.

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Technology innovations can be used to mitigate natural resource constraints.

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Singapore has adopted numerous technologies to enhance food security.

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Areas include urban farming, processing technology and alternative food sources.

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Singapore's model provides a good example to increase self-production of food.

Distillery Stillage: Characteristics, Treatment, and Valorization

Distilleries are among the most polluting industries because ethanol fermentation results in the discharge of large quantities of high-strength liquid effluents with high concentrations of organic matter and nitrogen compounds, low pH, high temperature, dark brown color, and high salinity. The most common method of managing this wastewater (distillery stillage) is to use it for soil conditioning, but this requires thickening the wastewater and may cause soil pollution due to its high nitrogen content. Therefore, treatment of distillery stillage is preferable. This review discusses individual biological and physico-chemical treatment methods and combined technologies. In addition, special attention is paid to valorization of distillery stillage, which is a valuable source of polysaccharides and volatile fatty acids (VFAs), as well as natural antioxidants, including polyphenols and other bioactive compounds of interest to the pharmaceutical, cosmetic, and food industries. New directions in improvement of valorization technologies are highlighted, including the search for new eutectic solvents for extracting these compounds. Such technologies are essential for sustainable development, which requires the use of management and valorization strategies for recovery of valuable compounds with minimal disposal of waste streams.