## 3 Results
### Powders--Morphology, Particle Size Distribution and other Physicochemical Properties
Additionally, it can also be a result of the penetration of ice crystals into oil droplets and the distribution of the interfacial membrane, therefore leaking the oil from the core to the surface, leading to a higher amount of surface oil in the powders [18]. In turn, [PERSON] et al. [51] reported that encapsulation efficiency is correlated with particle sizes. In their study, the lowest encapsulation efficiency was achieved for the smallest particle fraction, and it was assumed that due to a large surface-to-volume ratio of small powder particles, the probability of oil droplets being in contact with the particle surface increases, which leads to more surface oil. This is in accordance with our study, where particle mean diameter D\({}_{3,2}\) was in the range of 22.62 \(\upmu\)m (LMG) to 24.20 \(\upmu\)m (LMW) in SD powders. The largest average diameter of D\({}_{4,3}\) particles was 47.35 \(\upmu\)m for powder EMG obtained by the SD technique. This value was really high when compared to EMW (28.33 \(\upmu\)m) and powders that contain linseed oil: 34.46 \(\upmu\)m (LMW) and 37.35 \(\upmu\)m (LMG). This is in agreement with the results published by [PERSON] et al. [48] for linseed oil encapsulated by mixing maltodextrin with gum arabic (23.03 \(\upmu\)m) and WPC (17.98 \(\upmu\)m), which the authors explained by the high emulsion viscosity. Even smaller diameters D\({}_{4,3}\) for powders that were WPC coated in the range of 10.04 to 10.91 \(\upmu\)m were reported by [PERSON] et al. [52]. Similarly, [PERSON] et al. [49] reported particle diameters in the range from 14.20 to 25.30 \(\upmu\)m for powders with maltodextrin and gum arabic and attributed these results to higher emulsion viscosity, which is a crucial factor resulting in the larger microcapsule size of powders. Powders containing gum arabic also had the highest span values of 1.90 and 1.99 for samples containing oil and esters, respectively. However, the SSA value in all powders was at the same significant level (0.25-0.27 m\({}^{2}\)/g). Elsewhere, [PERSON] et al. [53] reported that the type and concentration of wall material significantly influence the size (D\({}_{3,2}\)) and SSA of spray-dried powders. In their study, modified starch (Hi-Cap 100, refined from waxy maize) resulted in larger particles with smaller SSA compared to skim milk powder. Surface oil content differed between prepared powders from 4.42% (LMG) to 11.48% (LMW), both obtained by freeze-drying (Table 3). Apart from surface oil content variation, the composition of fatty acids was relatively stable and typical for high-ALA linseed oils [54,55]. ALA ranged from 50.43% (LMG) to 53.43% (EMW), in both powders prepared through freeze-drying. It points out that part of ALA can be easily oxidizable, even in the form of powder. The induction period of used linseed oil was 2.40 h, while that of prepared ethyl esters was only 1.23 h (Figure 5). A similar phenomenon was determined using tridocosahexa-aenoin (more stable) and ethyl docosahexaenoicaenoate [56]. The lower oxidative stability of ethyl esters may be the result of the degradation of natural antioxidants such as tocopherols, phenols, and flavonoids present in linseed oil [57] during their preparation. The induction periods of the prepared powders are presented in Figure 5. It is clearly visible that the type of drying technique was decisive for the oxidative stability of the obtained powders. Spray-drying resulted in approximately 4-fold more stable powders in relation to freeze-drying. Among spray-dried powders, the highest oxidative stability exhibited samples were made with WPC (7.17 h vs. 6.98 h for powders of ethyl esters and linseed oil, respectively). Powders with gum arabic exhibited 2-3-fold lower stability than those corresponding with WPC.