Content of selected antioxidative compounds in green asparagus depending on processing before freezing and on the period and conditions of storage
2007
Gebczynski, P.,Krakow Agricultural University (Poland). Dept. of Raw Materials and Processing of Fruit and Vegetables
The content of antioxidative compounds was evaluated in frozen green asparagus produced with the traditional technology from the material blanched before freezing or with the modified technology from cooked asparagus. Compared with blanched asparagus, the product cooked before freezing contained more dry matter and polyphenols, similar amounts of beta-carotene, less carotenoids and vitamin C and its antioxidative activity was lower. During a 12-month storage at -20 deg C and -30 deg C a steady decrease in the level of the analysed constituents was observed in frozen products prepared for consumption. Compared with the raw material, asparagus prepared for consumption after the 12-month period of refrigerated storage contained 56-62 percent of vitamin C, 55-71 percent of polyphenols, 73-81 percent of beta-carotene, 74-89 percent of carotenoids while its antioxidative activity was reduced to 65-73 percent. In products obtained using the modified method the level of the analysed constituents was similar or a little higher than in the traditional products. Frozen products stored at -30 deg C were usually characterised with a higher content of analysed constituents and a higher level of the antioxidative activity in comparison with frozen asparagus stored at -20 deg C. Sensory quality of traditional frozen products slightly exceeded that of frozen products obtained using the modified method. The quality of products stored at -30 deg C was also better than that of products stored at -20 deg C
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