Comparison of amino acid content and protein quality in raw broccoli and in broccoli after technological and culinary processing
2010
Kmiecik, Waldemar | SŁUPSKI, JACEK | LISIEWSKA, ZOFIA
The aim of the present work was to evaluate the content of amino acids and the quality of protein in broccoli. The investigation covered primary inflorescences, fresh florets after cooking and two frozen products after a 12-month storage at-20C, which were prepared for consumption as follows: the traditional product (broccoli blanched before freezing, then cooked before consumption); and the modified, ready-to-eat product (broccoli cooked before freezing, then defrosted and heated in a microwave oven prior to consumption). Both fresh broccoli and broccoli prepared for consumption were very good sources of amino acids. In all the samples the dominant amino acids were glutamic acid and aspartic acid. In the products prepared for consumption, the limiting amino acid was tyrosine and phenylalanine. Compared with the total content of amino acids in the raw material, fresh florets after cooking contained 88% of amino acids, whereas products from frozen broccoli contained 74 and 97% in the traditional and modified products, respectively. The proportion of essential amino acids in total amino acids was in the range of 40-45%. The lowest essential amino acids index was found for protein in the traditional frozen product (105) and the highest for protein in raw broccoli (125). This study was conducted to determine the content of amino acids in fresh broccoli and in fresh cooked directly after harvest as well as in broccoli prepared for consumption from frozen products obtained using the traditional method (blanching before freezing) and the modified method (cooking before freezing - the do-it-for-me product). The methods of producing the frozen broccoli was described in detail in the Material and Methods section so that it could be easily introduced by manufacturers.
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