# Chemical and Sensory Properties of Corn Extrudates Enriched with Tomato Powder and Ascorbic Acid
## 3 Results and Discussion
### Extrusion Influence on Carotenoids
Likewise, at lower extrusion temperatures, the zeaxanthin content decreased in the largest number of samples, from which it can be concluded that it is somewhat more sensitive to the conditions prevailing during extrusion than lutein. The authors of [32] also researched the stability of corn lutein and zeaxanthin during extrusion and traditional flaking, and the degradation depended on the formulation of raw materials. The addition of chia and quinoa increased the degradation. Higher level of lipids, especially unsaturated fatty acids, led to the formation of free radicals, which reacted with carotenoid molecules, so \(\beta\)-carotene was completely lost during the processes. The authors of [33] showed that by optimizing the feed moisture between 13.2 and 13.7% and the barrel temperature between 120 and 132 \({}^{\circ}\)C, the \(\beta\)-carotene content originating from corn maize can be increased and the lutein and zeaxanthin contents are minimally lost. The proportion of lycopene in the raw samples increased proportionally to the TP content, ranging from 11 mg/100 g to 58 mg/100 g (Table 2). AA caused an increase in the analyzed lycopene content. After extrusion at both temperature regimes, no lycopene was detected. The authors of [12] showed that lycopene can be retained during extrusion, but in very small amounts. More importantly, they stated that the degree of degradation depends on the source from which the lycopene comes. The use of a physically resistant material such as tomato skin led to a significantly higher preservation of lycopene compared to the use of tomato paste. The same authors attributed the poor retention of lycopene originating from tomato paste to the extreme conditions that were applied during the preparation of the paste itself. It must be kept in mind that the raw material used in this research was spray-dried TP that had already undergone intense oxidation during drying, so the stress caused by extrusion caused the additional degradation of these molecules. Finding suitable, cheap and accessible raw materials is interesting from a nutritional point of view, since it was proved in [1] that extrusion increases the bioaccessibility of lycopene. \(\alpha\)-Carotene and 13-_cis_-\(\beta\)-carotene were detected only in mixtures containing 8% TP (Table 2). During extrusion at both temperature regimes, the complete degradation of these compounds occurred. The high sensitivity of these carotenoids originating from pumpkin during extrusion has been shown [15], but in this research, the ascorbic acid acted favorably on them, which resulted in their preservation. 9-_cis_-\(\beta\)-carotene (Table 2) was not detected in the mixtures containing pure corn grits, and its proportion increased proportionally to the addition of TP: 0.24 mg/100 g in the samples with the addition of 4% TP and 0.29 mg/100 g in those with the addition of 6% TP, while slightly higher values were recorded in the samples with AA (0.52 to 0.67 mg/100 g). AA acted as protection during the extraction and analysis of the samples. No 9-_cis_-\(\beta\)-carotene was detected after extrusion at both temperatures. The authors of [2] investigated the behavior of \(\beta\)-carotene as a model substance during different extrusion conditions, and they showed that 9-_cis_-\(\beta\)-carotene is degraded to a certain extent, but not completely, as this depends on the extrusion temperature, screw speed and dosing location. However, degradation is primarily a consequence of oxidation, and of thermal and mechanical stresses during extrusion. The temperature influence on carotenoids in general has been studied a lot. In the research conducted by the authors of [34], pasteurization did not affect the content of total carotenoids (\(\beta\)-carotene and lycopene) in tomato puree.