# Technological Properties of Tritordeum Starch
## 3 Results and Discussion
### Starch Retrogradation  
Starch retrogradation is a process in which disaggregated amylose and amylopectin chains in a gelatinized starch paste reassociate to form more ordered structures, leading to the creation of crystallites. It is accompanied by a gradual increase in rigidity and phase separation between polymers and leads to syneresis. Retrogradation is influenced by many factors, like the botanical origin of starch as well as its concentration and temperature and the presence of additional substances present in food, like, for example, salts, carbohydrates, etc. This process has a negative effect on the sensory and storage features of many starch foods, like, for example, bread staling. But, on the other hand, this process is desirable for some starchy food products in terms of texture development and nutritional benefits, since retrograded starch is not digested by enzymes. The recrystallization kinetics of aging gelatinized starch can be described by the Avrami equation (Equation (4)). In general, changes occurring during retrogradation can be described by the extent of this process (\(\Delta\Delta_{\infty}-\Delta\Delta_{0}\) in the Avrami formula), and also by its rate (rate constant k). The higher the value of the constant rate k, the faster the process occurs in the initial period (the course of the curve is sharper) [13; 14].  
Data related to the starch retrogradation phenomenon are shown in Figure 4, and calculated the Avrami equation parameters are collected in Table 6.  
The rate constants (k values) decreased in the following order: WaS \(>\) BuS \(>\) WdS \(>\) WhS \(>\) BaS \(>\) TrS. As can be observed, WaS was characterized by a distinctively different course of retrogradation process, compared to the other analyzed samples, that manifested as a much higher value of the k constant (0.0548), resulting in a faster course of retrogradation at the beginning of this process.  
The calculated k values for tritordeum (0.0022) and barley (0.0030) starches were rather similar, whereas for wheat starches (WhS and WdS), these values were 3-4 times higher, reaching 0.075 and 0.0084, respectively (Table 6). Data in the literature [13] related to k based on a turbidimetric method for cereal starches were in a rather broad range (0.0007-0.0787). For oat starch, the reported k value (0.0018) was close to those calculated for tritordeum and barley starches. On the other hand, the highest value (0.0787) was recorded for wheat starch [13], and it was the same magnitude as that for regular wheat starch (WaS).  
But at the same time, it was an order of magnitude larger than the k values calculated in this research for WdS and WhS. The starch retrogradation process is disturbed by the presence of lipids [13], and the lowest k value was calculated for TfS, which was also characterized by the highest lipid content (Table 1).  
The extent of the retrogradation process (AA\({}_{\infty}-\Delta\)A\({}_{0}\)) decreased in the following order: WdS \(>\) BaS \(>\) BuS \(>\) TfS \(>\) WhS. For the final value (AA\({}_{\infty}\)), this order was different: BuS \(>\) TfS \(>\) BaS \(>\) WhS \(>\) WaS (Table 6). Reported data [31] for the extent of retrogradation were similar or higher (0.8244-1.2444), and the lowest value was observed for wheat starch, and also, this starch was characterized by the lowest final value (2.1442), which was close to the value observed for WdS in this research.  
Taking into consideration the above-mentioned data, it could be concluded that tritordeum starch would be rather stable during prolonged storage due to the low k value, and also the relatively low extent of this process. This can be an indicator that TfS could become a good additive for commercial food products when changes related to the retrogradation process could worsen the quality of the product.