# Fresh Broccoli in Fortified Snack Pellets: Extrusion-Cooking Aspects and Physical Characteristics
## 3 Results and Discussion
### Effect of Variables on Selected Physical Properties of Snack Pellets  
During the tests, we noted that the mixture recipe had an influence on the snack pellet expansion index. In general, increasing the amount of fresh broccoli in the recipe significantly reduced the value of the expansion index of extruded snack pellets (Table 2) with a high correlation coefficient (r = \(-\)0.898). [PERSON] et al. [36] noted similar dependencies for extruded corn crisps with a broccoli powder addition. [PERSON] et al. [32] also reported a decrease in the rice snack expansion index with an increase of fresh vegetable pulp addition. In our work, the highest value of the expansion index (3.05) for control snack pellets without fresh broccoli addition was obtained using the speed of the extruder screw set at 60 rpm with the moisture level of the mixture at 34%. The lowest value of the expansion index (1.43) was seen for samples with an initial moisture content of 32%, processed with a screw speed of 100 rpm, and incorporating a fresh broccoli addition of 30%. Despite the relatively high values of the expansion index, the obtained snack pellets were characterized by a compact structure without visible pores or bubbles. Generally, as the screw speed increased, we noted an increase in the expansion index values. [PERSON] et al. [36] saw the same effect during extrusion-cooking of corn flour and broccoli powder mixtures. Therein, the effect was greatest in the case of recipes with a 10% fresh broccoli addition. We discovered that the increasing moisture content of raw material mixtures led to a higher value of the expansion index. In the specific scenario of the extrusion-cooking process involving mixtures containing 20% fresh broccoli addition at a screw speed of 100 rpm, we observed that as the moisture level of the raw material mixture increased, there was a reduction in snack pellet expansion index. The analysis of the bulk density of snack pellets manufactured using various recipes and process parameters shows that in most cases, both the initial moisture level of the extruded mixtures and the speed of the extruder screw had substantial influence on the values of the tested feature (Table 2). The highest bulk density value (379 kg m\({}^{-3}\)) was documented for control snack pellets obtained from mixtures without fresh broccoli addition, with a moisture level of 32% and an extrusion process conducted at 100 rpm of screw speed. In contrast, snack pellets derived from a mixture containing 20% fresh broccoli at an initial moisture content of 36% and processed at a screw speed of 60 rpm demonstrated the lowest bulk density value--256 kg m\({}^{-3}\). In the case of snack pellets with 10% fresh broccoli, the value of the bulk density decreased as the speed of the extruder screw increased. [PERSON] et al. (2018) noted a similar outcome during extrusion-cooking of directly expanded rice snacks with fresh vegetable pulp addition. In general, for pellets with 20% and 30% broccoli, the bulk density values increased with the increase in the speed of the extruder screw. [PERSON] et al. (2018) also saw a similar tendency for snack pellets with an onion addition. We noted that snack pellets processed through extrusion-cooking were characterized by excellent durability (Table 2). Indeed, throughout the testing, we determined that the extrusion-cooking parameters did not have an important impact on the durability of the obtained pellets. We observed that adding fresh broccoli to snack pellets allows for lower values of durability, but the correlation was low (r = 0.448). The lowest durability (99.06%) was recorded in the case of snack pellets obtained from mixtures with 30% fresh broccoli, a