## 3 Results and Discussion  
### The Changes in pH, TA, TSC, LAB Viability and Color  
The microbiological quality of food products is particularly pertinent in view of the fact that microbial contamination can reduce or even eliminate the safety of consumption and cause food poisoning [32]. Pathogenic microbes (such as coliforms, _Salmonella_ sp. or molds) presented in food products not only make them hazardous from the infectious standpoint, but, in addition, may change the chemical, physical and organoleptic properties or change the contents of the active ingredients [32]. As a result of thermal treatment and pasteurization, as well as during storage time, no coliforms, _Salmonella_ sp. and molds were detected; therefore, it can be concluded that the products were microbiologically safe to ensure no undesirable microorganism competition for LAB. One of the key factors in the fermentation process is to improve nutritional value and sensory properties through the production of metabolites such as lactic acid, while extending shelf life by lowering the pH value [33; 34]. As can be seen in Figure 1, the LAB content in the beverages markedly increased as a result of fermentation (\(p\) < 0.05). In both variants, the initial value was determined as 1.10 \(\times\) 10\({}^{8}\) CFU/g. The highest LAB content was observed for sample CPC15% on day 1 (1.38 \(\times\) 10\({}^{12}\)\(\pm\) 0.09 CFU/g). This result is in agreement with the findings of [PERSON] et al., who reported an almost three-fold increase in lactic acid bacteria counts as a result of amelina meal solid-state fermentation [8]. It should be noted that at any time, the LAB viability was maintained in the CPC-based samples over the 10\({}^{10}\) CFU/g level. The recommended minimum for yogurt is \(>\)10\({}^{6}\) CFU/g LAB viability, and the highest obtained results are approximately two-fold higher than the recommendation. For some oil cakes, the residual oil should be considered as it is known that various oils could affect bacterial growth and the viability due to their antimicrobial properties. However, [PERSON] et al. reported that amelina oil can stimulate LAB growth while inhibiting pathogen growth [25]. The authors suggest that fatty acids from amelina oil and other amelina compounds (such as amino acids) can nourish LAB. In fact, amelina is abundant in essential amino acids (such as leucine, valine, phenylalanine, lysine, isoleucine) [35], thus, the favorable amino acid content can induce a synergistic effect for LAB growth and make CPC an excellent matrix for fermentation. Moreover, amelina is also capable of producing mucilage, which can be used as a prebiotic material and carrier for bacteria acting as a prebiotic [11; 36]. Table 1 presents the results of the pH, titratable acidity (TA) and total solids content (TSC) measurements during the storage time. The shelf life of yogurt should be around twenty days under refrigeration, and the product should maintain its own characteristics during storage [37]. The physicochemical properties of CPC were strongly modified by the fermentation process. The initial pH values were 6.28 \(\pm\) 0.01 and 6.32 \(\pm\) 0.05 for samples CPC-15% and CPC-20%, respectively. As a result of fermentation, a significant increase in the samples' acidity (4.65 \(\pm\) 0.01-CPC-15% and 4.56 \(\pm\) 0.02-CPC-20%, respectively) was observed (_p_ < 0.05). A decline in pH suggests an increase in the organic acids content produced by the microorganisms [8]. Acidification of the product protects against spoilage and pathogenic microorganisms, as well as being one of the main factors determining taste and aroma. TA also increased significantly during the fermentation process (_p_ < 0.05). The highest TA content was observed for the CPC-15% sample on day 21 of storage (1.25 \(\pm\) 0.14 mg lactic acid/g). The observed acidification is in line with earlier findings that reported a decrease in pH and the production of organic acids in amelina meal fermented with fungi [8; 38].