We studied how storing fresh sardines (Sardina pilchardus) on ice for 0–15 days would affect lipid quality and sensory acceptance after the sardines were later canned. Average moisture and diacylglycerol contents showed a decreasing trend during storage time for sardines stored for to 0–10 days and an increasing trend for samples stored for 13–15 days. Total lipid and triacylglycerol average values increased with storage time of 0–10 days. In contrast, sardines stored for 13–15 days showed decreased values of lipids and triacylglycerols. Increased storage times also led to increased average saturated fatty acid (STFA) content and browning and decreased polyunsaturated fatty acid (PUFA) values and PUFA/STFA and ω3/ω6 ratios. Notably, the effect of storage time on PUFA/STFA and ω3/ω6 ratios and browning development was found significant (p < 0.05). Sensory descriptors revealed only slight quality differences with previous storage on ice for 0-10 days. In contrast, a substantial (p < 0.05) decrease (appearance and texture) was detected in samples corresponding to a 13–15-day period, such samples being considered unacceptable. Storage on ice not exceeding 10 days is recommended for sardines before being shipped to canneries for further processing. Furthermore, the use of efficient storage including preserving technologies would be desirable.
Vitamin E, as the most important lipophilic antioxidant of eukaryotic cells, plays an important role in human nutrition. So far, information has focused on the content of vitamin E in raw food materials or foods, and its losses under various processes and culinary treatments. However, the different degradation rates of its eight different forms, four tocopherols and four tocotrienols, during the preparation of oven-ready products have not been clearly and in detail described. Therefore, the aim of our research was to determine the changes in the content of tocochromanols and to evaluate the risks of the loss of these substances while preparing frozen French fries baked in classic and microwave ovens. The tocochromanols were determined using reverse-phase high-performance liquid chromatography with an amperometric detector. The results showed a statistically insignificant loss of γ-tocopherol (γ-T), δ-tocopherol (δ-T), γ-tocotrienol (γ-T3) and δ-tocotrienol (δ-T3). Conversely, the losses of α-tocopherol (α-T), α-tocotrienol (α-T3), the total content of tocochromanols and the vitamin E content in α-tocopherol equivalents (α-TE) were statistically significant (p < 0.01). These losses were independent of the type of baking (conventional heating, heating with air circulation, grill, microwave heating, microwave and grill heating) and averaged at 0.80 mg/kg of the original fries (9.1% of the original content) for α-T, 0.44 mg/kg (36.6%) for α-T3, 1.11 mg/kg (12.7%) for the sum of the tocochromanols and 0.92 mg/kg (12.6%) for the vitamin E content expressed as α-TE. These dishes contained 0.4% to 26% of the daily requirement of vitamin E, based on a 100 g portion, depending on the fat used in the manufacture of the products. The choice of the right frying medium on the part of the manufacturer can increase the content of vitamin E both in the semi-finished product and in the final food, and consequently also its dietary intake.
Vitamin E was described in 1922 and its basic mechanism of action was elucidated in 1931. However, some new compounds with vitamin E activity have been discovered, and some unknown mechanisms of action of this vitamin in vivo have been described in a research conducted in the last 20 years. Therefore, the present review provides a comprehensive, current view of vitamin E.