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.

中文翻译：

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酿造副产物的循环潜力：营养上有价值的化合物和抗氧化活性评估

酿造工业产生大量的固体和液体废物，从而导致处置问题。酿造废谷物（BSG）和酿造废酒花（BSH）是酿造行业的重要副产品，具有高价值的化学成分。在这项研究中，从两种不同类型的淡啤酒（帝国红和比利时浓啤酒）的生产过程中获得的BSG和BSH在有价值的成分（包括蛋白质，碳水化合物，脂肪，膳食纤维，β-葡聚糖，阿拉伯木聚糖，多酚和酚酸以及抗氧化活性（还原铁抗氧化能力测定（FRAP），2,2-二苯基-1-吡啶并肼基（DPPH）和2,2'-叠氮双（3-乙基苯并噻唑啉-6-磺酸酸）二铵盐（ABTS））。在BSH和BSG样品中均观察到明显的总多酚浓度（平均约10 mg GAE / g干物质）；但是，比利时强麦啤酒的副产物中的检出水平比帝王红高约1.5倍。使用经过验证的色谱方法对游离和结合的酚酸进行定量。与BSH相比，BSG样品中发现的总酚酸（TPA）含量高得多（约高16倍）。最后，验证了它们的抗氧化潜力。比利时强麦芽啤酒的副产品BSG和BSH均显示出比废谷物和自酿制帝国红麦芽的啤酒花明显更高的抗氧化能力（抑制浓度（IC50）值低1.5倍）。总之，BSG和BSH可能被认为是蛋白质，碳水化合物，纤维，