Rootlets, a Malting By-Product with Great Potential

Monitoring Fusarium toxins from barley to malt: Targeted inoculation with Fusarium culmorum

Molds of the genus Fusarium infect nearly all types of grain, causing significant yield and quality losses. Many species of this genus produce mycotoxins, which pose significant risks to human and animal health. In beer production, the complex interaction between primary fungal metabolites and secondarily modified mycotoxins in barley, malt, and beer complicates the situation, highlighting the need for effective analytical methods to quickly and accurately monitor these toxins. We developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to simultaneously analyze 14 Fusarium toxins, including modified forms (deoxynivalenol (DON), DON-3-glucoside, 3-acetyl-DON, 15-acetyl-DON, nivalenol, fusarenone X, HT-2 toxin, T-2 toxin, the enniatins A, A1, B, B1, beauvericin, and zearalenone) in barley and throughout the malting process. Stable isotope dilution assays (SIDAs) and matrix-matched calibration were used for quantification. A micro-malting setup was established to produce Fusarium-contaminated barley malt under reproducible conditions using targeted inoculation with F. culmorum. Mycotoxins were quantified throughout the malting process and compared to the content of fungal DNA. Further, the impact of various malting parameters was investigated, thus revealing that different malting scenarios exhibited different toxin enrichment patterns. We demonstrated that mycotoxin concentration and the ratio of DON to DON-3-glucoside changed throughout the malting processes, depending on fungal spore concentrations, germination temperature, and malting temperature. The study highlights the complexity of mycotoxin dynamics in malt production and the importance of optimized processing conditions to minimize toxin levels in final malt products.

Is malting an absolute must? Native triticale as a stand-in for barley malt in the brewing process

BACKGROUND

To remain competitive, brewers must innovate by incorporating novel elements beyond traditional styles. Thus, exploring triticale as a modern substitute for barley malt is promising, especially given its higher amylolytic activity compared to barley. This study aimed to assess the impact of substituting up to 50% of barley malt with unmalted triticale on green beer quality, encompassing multiple stages from wort production to primary fermentation at a laboratory scale.

RESULTS

Triticale-based worts (ratios 10-50%) had lower extract content than 100% barley malt. However, incorporating 10% of triticale led to only a 1% decrease in extract content compared to the all-malt wort. Shearzyme® 500L, an endo-1,4-β-xylanase with β-glucanase side activity, effectively addressed wort viscosity by breaking down arabinoxylans and β-glucans in triticale cell walls. All triticale-based beers exhibited lower ethanol content compared to reference beer, as is typical when using adjuncts. In green beer, a 50% triticale ratio lowered ethanol content by 16% (without enzyme) and 19% (with enzyme) compared to 100% malt beer. However, green beer with 10% triticale had satisfactory levels of total polyphenol and vicinal diketone content, among other parameters.

CONCLUSION

Commercial enzyme application significantly enhanced proteolytic activity within the grain. Fermentations of enzyme-treated worts showed higher amino acid levels, further confirming the increased proteolytic activity facilitated by the chosen enzyme. Overall, this study provides a comprehensive analysis of the brewing process using native triticale. Building on this foundation, future studies will focus on optimizing mashing conditions to enhance the fermentation profile of the wort. © 2024 Society of Chemical Industry.

Novel formulations for developing fresh hybrid cheese analogues utilizing fungal-fermented brewery side-stream flours

This study investigated the development of hybrid cheese analogues (HCA) made with fermented brewery side-stream ingredients (spent yeast and malt rootlets) and dairy milk. Different percentages of side-stream flours (3.5%, 5%, and 7.5%) were mixed with pasteurized milk, and the developed HCA were evaluated for their biochemical and textural properties. The addition of a fermentation step improved nutrient availability and led to pH (range 4.79-5.60) and moisture content (range 45.86%-61.29%) similar to traditional animal-based fresh cheeses (control). The inclusion of side-stream flours led to coagulation, even without rennet addition. The higher the concentration of the flour used, the faster the coagulation time, suggesting synergistic effect between the enzymes of the rennet and the enzymes present in the fermented side-stream flours. Nevertheless, textural properties were inferior compared to the control. Selected HCA formulations with added 3.5% flour exhibited increased counts of enterococci and enterobacteria cell densities, ranging from 7.28 ± 0.03 to 7.72 ± 0.09 log CFU/g and 4.90 ± 0.16 to 5.41 ± 0.01 log CFU/g, respectively. Compared to the control sample, HCA formulations exhibited higher concentrations of organic acids, peptides, and free amino acids (FAAs). Lactic acid reached up to 23.78 ± 0.94 g/kg of dry matter (DM), while the peptide area reached up to 22918.50 ± 2370.93 mL⋅AU. Additionally, the total concentration of individual FAAs reached up to 2809.74 ± 104.85 mg/kg of DM, contrasted with the control, which resulted in lower concentrations (847.65 ± 0.02 mg/kg of DM). The overall findings suggested that despite challenges in microbiological quality and textural properties, HCA produced with the inclusion of up to 3.5% brewery side-stream flours could be a sustainable solution to produce nutritious dairy alternatives.

Natural Occurrence of Nitrite-Related Compounds in Malt and Beer

Despite sufficient control of volatile N-nitrosamines in foods and beverages, little attention remained on nonvolatile nitroso compounds, which are mostly unknown and relative to nitrite reactions. In a recent study, new compounds related to reactions of nitrite in beer were pyruvic acid oxime, 4-nitrosophenol, 4-cyanophenol, N-nitrosoproline ethyl ester, nitrosoguaiacol, and 2-methoxy-5-nitrophenol, as well as the already known N-nitrosoproline. The present study is intended to observe their natural occurrence in commercial beers and malts. All 22 nitrite-related products (N-products) were monitored in almost 200 samples of beers and malts. As many as 17 N-products were detected in malts, and all 22 N-products were found in beers. The hierarchical clustering grouped samples based on similarities of detected N-products by frequency of their appearance and level of response. Between N-products and N-nitrosodimethylamine concentrations in malts, only moderate Pearson correlations were found. The same applied to N-product correlations with the apparent total nitroso compound determination in beers.

From Waste to Taste: Application of Fermented Spent Rootlet Ingredients in a Bread System

The process of upcycling and incorporating food by-products into food systems as functional ingredients has become a central focus of research. Barley rootlets (BR) are a by-product of the malting and brewing industries that can be valorised using lactic acid bacteria fermentation. This research investigates the effects of the inclusion of unfermented (BR-UnF), heat-sterilised (BR-Ster), and five fermented BR ingredients (using Weissella cibaria MG1 (BR-MG1), Leuconostoc citreum TR116 (BR-TR116), Lactiplantibacillus plantarum FST1.7 (BR-FST1.7), Lactobacillus amylovorus FST2.11 (BR-FST2.11), and Limosilactobacillus reuteri R29 (BR-R29) in bread. The antifungal compounds in BR ingredients and the impact of BR on dough rheology, gluten development, and dough mixing properties were analysed. Additionally, their effects on the techno-functional characteristics, in vitro starch digestibility, and sensory quality of bread were determined. BR-UnF showed dough viscoelastic properties and bread quality comparable to the baker's flour (BF). BR-MG1 inclusion ameliorated bread specific volume and reduced crumb hardness. Breads containing BR-TR116 had comparable bread quality to BF, while the inclusion of BR-R29 substantially slowed microbial spoilage. Formulations containing BR-FST2.11 and BR-FST1.7 significantly reduced the amounts of sugar released from breads during a simulated digestion and resulted in a sourdough-like flavour profile. This study highlights how BR fermentation can be tailored to achieve desired bread characteristics.

Enzyme and Antioxidant Activities of Malted Bambara Groundnut as Affected by Steeping and Sprouting Times

Bambara groundnut (BGN) is termed a complete food due to its nutritional composition and has been researched often for its nutritional constituents. Malting BGN seeds have shown improved nutritional and functional characteristics, which can be used to produce an amylase-rich product as a functional ingredient for food and beverage production in homes and industries. The aim of this study was to investigate the enzyme and antioxidant activities of malted BGN affected by steeping and sprouting times. BGN was malted by steeping in distilled water at 25-30 °C for 36 and 48 h and then sprouted for 144 h at 30 °C. Samples were drawn every 24 h for drying to study the effect of steeping and sprouting times on the moisture, sprout length, pH, colour, protein content, amylase, total polyphenols, and antioxidant activities of the BGN seeds. The steeping and sprouting times significantly affected the BGN malt colour quality and pH. The protein content of the malted BGN seeds was not significantly different based on steeping and sprouting times. Steeping and sprouting times significantly affected the α- and β-amylase activities of the BGN seeds. The activity of amylases for 36 and 48 h steeping times were 0.16 and 0.15 CU/g for α-amylase and were 0.22 and 0.23 BU/g for β-amylase, respectively. Amylase-rich BGN malt was produced by steeping for 36 h and sprouting for 96 h. Amylase-rich BGN malt can be useful as a functional food ingredient in food and beverage formulations.

Metabolite profile and antioxidant potential of wheat (Triticum aestivum L.) during malting

In addition to barley, wheat malt is considered an important beer material because of the recent popularity of wheat beer in the global market. The changes in metabolite profiles and antioxidant potential of wheat samples collected every 24 h during malting were investigated. Dynamic metabolite changes through ¹H NMR-based metabolomics approaches, quantitative individual phenolic acids by high-performance liquid chromatography and antioxidant potential by colorimetric methods were assessed. Orthogonal projection to latent structure with discriminant analysis showed that metabolites were responsible for discrimination of each malting stage for wheat. Phenolic acids, whose main component was ferulic acid, increased with time during wheat malting. Much higher phenolic acid contents were found in rootlets/acrospires than in the bodies of dried wheat malt. The overall results of this study provide novel information on changes in dynamic metabolites during wheat malting.

Biochar from Spent Malt Rootlets and Its Application to an Energy Conversion and Storage Device

Activated carbon obtained from biomass wastes was presently studied in order to evaluate its applicability in an energy storage device. Biochar was obtained by the carbonization of spent malt rootlets and was further processed by mild treatment in NaOH. The final product had a specific surface of 362 m2 g−1 and carried Na, P and a few mineral sites. This material was first characterized by several techniques. Then it was used to make a supercapacitor electrode, which reached a specific capacitance of 156 F g−1. The supercapacitor electrode was combined with a photocatalytic fuel cell, making a simple three-electrode device functioning with a single alkaline electrolyte. This device allows solar energy conversion and storage at the same time, promoting the use of biomass wastes for energy applications.