## 1 Introduction  
The food and drink processing sectors are undergoing an intense change in production conditions and systems. These changes are due, on the one hand, to modifications in the habits of our modern societies and, on the other hand, to the health requirements of each individual. Currently, one of the main trends in nutrition is the objective of physical health. This wellbeing is achieved by choosing foods that have a positive impact on health.  
Barley is a herbaceous plant that is among the oldest cultivated cereals [1]. It is eaten raw or roasted and, in ancient times, was also used to make nutritious but very heavy bread. Today, only 33% of barley production in the world is intended for human consumption [2]. It is mainly germinated to make malt for beer and whisky. However, in the last few years, barley grass or grass juice made from young barley shoots has appeared for detox or nutritional purposes. The barley grain is rich in carbohydrates, which is a source of energy. Barley also contains fibers (especially hulled barley) that are good for digestion and bring satiety. Among these fibers, we find beta-glucans (soluble fibers), which play a crucial role in lowering blood cholesterol and bad cholesterol [3; 4].  
Several investigations have been focused on the study of the phenolic compounds because of their use in medication for a variety of diseases and their application in the conservation of comestible foodstuffs in the food industry [5]. Hence, their biological activities and health benefits also differ e.g., anti-inflammatory [6; 7; 8], anti-allergic [9], as well anti-carcinogenic properties [10; 11]. Additionally, the phenolic compounds have gained the attention of nutritional and therapeutic scientists for their effective exercises and their aptitude to scavenge free radicals and break radical chain reactions. Likewise, the use of high phenols has been correlated with a plethora of various pharmacological activities [12; 13; 14; 15].  
Barley has been used as a source of extraction of beer, one of the first popular fermented beverages in the history of mankind; the brewing process of beer has not changed much since its discovery. Generally, the process is based on the natural enzymatic activity that occurs throughout the malting of the seeds, the brewing of the seeds, and the fermentation of the word [16]. Beer is a complicated combination of ingredients that are fermented from raw material, yeast, malt, and hops, and includes a wide variety of several chemical elements that can act together at all phases of the brewing process [17]. Different groups of composites have been indicated to play a significant role in the flavor properties [18], for example, ketones, higher alcohols, aldehydes, esters, and organic acids, which contribute to the final sensory nature of beer, [19; 20; 21; 22; 23; 24]. The production of non-alcoholic beer using the thermal process is mostly applied in industry; in this case the beer is degassed and subsequently preheated in a plate heat exchanger. Afterwards, the beer is fed into the stripping section of a rectification column and the product flows through the column at a temperature between 43 \({}^{\circ}\)C and 48 \({}^{\circ}\)C. In the countercurrent, the product meets rising vapors that cause the selective separation of the alcohol from the product. Afterwards, the alcohol-free beer is introduced into an evaporator where the rectification process takes place [25].  
In this study, the stability of antioxidant compounds in malting barley seeds before and after the production of the final products was studied. These stability investigations were carried out in order to determine the most adequate control conditions while avoiding their degradation; also, the study aims to provide information on the impact of the fermentation processes on the products that are metabolized during this stage, which requires a strict control.