What is spent grain

BSG arabinoxylans include a significant water-extractable fraction and during enzymatic digestion they can release xylooligosaccharides with varying degree of polymerization Wang et al.

BSG phenolics are mainly contained in the barley husk, accumulated in cell walls and esterified to sugar residues, conditions that decrease their antioxidant activity since availability of free hydroxyl group is essential to stabilize free radicals Bhanja et al.

The major part of phenolic compounds in BSG are hydroxycinnamic acids, of which ferulic acid is the most abundant and in strong correlation with cereal antioxidant capacity. However, since ferulic acid is bound to the ligninocellulosic structure of BSG, it has low bioaccessibility. Bioprocessing can improve the bioaccessibility of phenolic compounds from fiber-rich cereal matrix.

This treatment led to an increase of the bioaccessibility of ferulic acid and other phenolic acids of bran in vitro Anson et al. In addition to the potential health benefits, when added to food, antioxidants control rancidity development, maintaining the nutritional quality and shelf-life of products. Nowadays, there is still a growing interest in finding natural sources of antioxidants to effectively replace synthetic ones, which have been related to toxic and carcinogenic effects Bouayed and Bohn, Additionally, BSG can also be a source of antioxidant peptides as previously shown for several cereal flours, including whole wheat.

These bioactive peptides, released through fermentation with lactic acid bacteria LAB , showed protection of cells from oxidation ex vivo as well as inhibition of linoleic acid oxidation Verni et al. Despite the high nutritional and functional potential, most of the BSG produced is used for feed or as substrate to produce bioethanol, lactic acid, xylitol and enzymes Nigam, Yet, BSG use as food ingredient is more limited due to its complex structure and consequent poor technological performance, which requires treatments able to reduce the negative impact on texture and sensory properties of the final food product Lynch et al.

Among these, pre-treatments with xylanase were effective in improving specific volume and texture of breads supplemented with BSG and increased the amount of soluble fibers Ktenioudaki et al. Similarly, fermentation, largely recognized as a technology able to improve sensory and technological properties of fiber-rich cereal by-products, was proven helpful to enhance nutritional and functional properties of BSG in different bread and beverages applications Gupta et al.

The focus of this study was to understand the effect of fermentation on the antioxidant properties of BSG. To enable the release or synthesis of antioxidant compounds in BSG, a biotechnological process based on fermentation with selected LAB and treatment with a commercial xylanase was developed.

The effects of bioprocessing on the antioxidant activity were investigated through an integrated multi-step approach including in vitro and ex vivo assays, study of BSG microstructure, and characterization of phenolic compounds and peptide profile.

All the strains were previously used as starters for fermentation and characterized for pro-technological properties growth and acidification performances, as well as the ability to increase antioxidant activity as expressed in their own food isolation matrix wheat, wheat germ quinoa, hop, hemp, faba bean, chickpea, carrots Di Cagno et al.

Before inoculation they were cultivated until the late exponential phase of growth was reached ca. KG, Staufen, Germany. Lactic acid bacteria strains were singly inoculated initial cell density ca. Yeasts, molds and total Enterobacteria were respectively enumerated on: Sabouraud Dextrose Agar Oxoid supplemented with chloramphenicol 0.

Samples of BSG not inoculated with the LAB strains but added with xylanase and incubated in the conditions used for fermentation, were also prepared and used as control eBSG. The list of treatments and codes is reported in Table 1. Fermentation was monitored by measuring, before and after incubation, pH, enumerating presumptive LAB, yeasts, molds, and total Enterobacteria as described above.

ME were further purged with nitrogen stream and stored at ca. The value of absorbance was compared with 75 ppm butylated hydroxytoluene BHT , which was used as the antioxidant reference. The analysis of total phenols in ME was performed according to the method of Slinkard and Singleton using gallic acid as standard.

The supernatant was used for analyses. Trolox 6-hydroxy 2,4,7,8-tetramethylchromancarboxylic acid was used as standard. The scavenging activity was expressed as Trolox equivalent. Peptides concentration was determined by the o -phtaldialdehyde OPA method as described by Church et al.

One hundred microliters of the above sample were mixed with 4. After 3 min, the degree of color development, representing the oxidation of linoleic acid, was measured spectrophotometrically at nm. A reference sample without the addition of antioxidants was included in the assay as negative control. Sections were applied to polysine coated microscopy slides.

Sections were stained with light green to visualize starch and proteins. The sections were then pre-incubated 40 min in PBS buffer with 2. Negative controls were made by replacing the primary antibody solution with PBS containing 0.

All incubations were performed in moisturized chambers at room temperature. Emissions were collected at — and — nm. To further confirm the results obtained from microscopy analysis, insoluble and soluble dietary fibers content was determined in raw and bioprocessed BSG according to the official AOAC International When ca.

Medium and all chemicals were purchased from Sigma Aldrich Italy. The concentrations were 0. At the end of incubation, MTT assay was performed Mosmann, Data were expressed as the percentage of viable cells compared to negative control.

Each experiment was carried out in triplicate. Free and bound phenolics were extracted as described in Verardo et al. The compounds were monitored at nm. Integration and data elaboration were performed using MassLynx 4. For the quantification of phenolic compounds, solutions of ferulic acid, chlorogenic acid, catechin, and quercetin in methanol were prepared and used as standard. Proanthocyanidins were extracted as described by Verardo et al. Fractions were tested for the antioxidant activity on DPPH radical.

Solvents were removed from collected fractions by freeze drying. Fractions were re-dissolved in sterile water, assayed for the antioxidant activity on DPPH radical and the peptide content by the OPA method as described above Rizzello et al.

After treatments, samples were subjected the scavenging activity on radical DPPH as described above. The peptides contained in the WSE fractions with the highest radical-scavenging activity were subjected to identification. Results from peptide identification were subjected to a manual evaluation, as described by Chen et al. All the microbiological and chemical analysis were carried out in triplicate for each batch of BSG.

Data of the ex vivo assays were analyzed with a statistical software: GraphPad Prism v7. P -values equal to or less than 0. Before incubation BSG had a pH of 5.

After fermentation, the pH of the inoculated samples ranged from 3. The lowest variation was observed when BSG was fermented with W. On the contrary, L. When BSG was inoculated initial cell density ca. The highest final cell density was observed for L. At the end of fermentation, yeasts and Enterobacteriaceae cell density was lower than 4.

BSG fermented with L. Before incubation rBSG had total phenol content 2. In BSG fermented with L. Fermentation with L. Peptides concentration before fermentation was All the data obtained from the biochemical characterization of raw and fermented BSG were subjected to principal component analysis PCA as shown in Figure 1. Factor 1 and 2 represented Figure 1. Figure 2. Data are the means from three independent experiments. Bars represent standard deviation. In both cases, cell density of LAB ranged from 5.

Extracts from raw and treated BSG were tested for the ability to inhibit lipid peroxidation. In this method, the concentration of peroxides decreases as the antioxidant activity increases Omwamba and Hu, Compared to the reference reaction mixture without antioxidants , the presence of all extracts inhibited linoleic acid autoxidation Figure 3.

Figure 3. The activity was measured under linoleic acid oxidation system for 8 days. The reaction mixture without the addition of the antioxidant was considered as a negative control. Intact layers of aleurone cells and large clusters of connective endosperm proteins characterized rBSG. Xylanase treatment eBSG , caused the extensive degradation of the aleurone cells, and the disassembling of the large protein clusters, apart for some proteins located in the aleurone cells still forming globular structures.

When fermentation with selected starters followed the enzymatic treatment, no further distinct impact on the microstructure was observed, although the protein appeared unevenly dispersed Figure 4. Figure 4. Small amounts were also observed in the pericarp.

Very few AX were detectable in bioprocessed samples inoculated with LAB after the xylanase treatment, both in aleurone cell walls and dispersed in the matrix, especially when L. Nevertheless, residual bound AX were seen in pericarp after enzymatic treatment and fermentation. Overall, the sequential bioprocessing treatments caused the protein arrangement in rows with globular structures Figure 5. Figure 5. Arabinoxylans are shown in red after labeling with LM11 antibody.

BSG morphology is shown in green with autofluorescence. These studies indicate that a protein intake at least two times higher than the FDA recommends is probably closer to optimal. Well lucky for you, spent grain is super high in fiber! Like really high. To put that in context, Healthline put together a list of the top 22 fiber-rich foods. Well I happened to smell some brussels sprouts yesterday, I should be good on fiber for like a week, right?

Most likely not. But what are we missing out on by not getting enough? Carbohydrates Carbohydrates can be a good source of energy for your body. In fact going completely without carbs over the long-term may not be a great idea. However, restricting them can pay dividends in your journey to health, wellness, and weight loss—even more so than a typical calorie restricted diet.

Yes, by far the biggest factor in determining your long term weight change—in addition to exercise—is how many total calories you eat. Still, for many individuals, a low-carb diet can be a great way to help reduce calories and can even be preferable to a typical lower calorie diet.

This is because many people are less hungry on a lower carb diet compared to a higher carb one Additionally, a study suggests that a lower carbohydrate diet might cause dieters to have a higher Basal Metabolic Rate than those on a higher carbohydrate diet. Or, translated into English, this mean that a low carb diet might help you burn more calories just laying on your couch than a higher carbohydrate diet would. People with type 2 diabetes improved their insulin sensitivity through a lower carbohydrate diet.

To summarize, a carbohydrate restricted diet may have additional benefits that a typical calorie restricted diet does not. More importantly though, lower carb diets might help you stay on your diet longer and lose more weight. Dieting is hard enough. Long meetings, emails in our inbox, classes, sporting events, and social activities all await our attention. Pop-Tart it is! This decision may not seem very important at the time, but it is. You've now added the To-Dos below to your personal list.

Happy eating! Thanks for Signing up. We sent you a verification email. Please verify to begin receiving our newsletter and using your account. Print Save. Photo: Chad Robertson. Yeast Yeast is the catalyst that turns grains into things like bread or beer, and also adds distinctive flavors. Want the inside scoop? Please check your inbox to verify your email address. Hot Stuff. Get the Tasting Table newsletter for adventurous eaters everywhere Sign up Your information will never be shared with a third party.

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