Growth and Changes of amino acid Contents in the Cultivation Process and During Storage of Thick Bean Sprouts by Different Cultivation Methods

Abstract

To improve the quality of thick bean sprouts and clarify their value as a material to supply amino acids, we cultivated thick bean sprouts of soybean and mung bean by the following methods and evaluated their growth and changes in the amino acid contents in the cultivation process and during storage : (1) Routine cultivation method (Control), (2) Carbon dioxide-enriched rotary cultivation (CRC), (3) Dipping in mixed phytohormone treated cultivation (DMP), and Dipping in mixed phytohormone combined application of artificial sunlight lamp cultivation (DPSL). The growth of both types of thick bean sprouts assessed in terms of the marketability of external quality was good in the order of DPSL>DMP>CRC>Control. By each cultivation method, the appropriate harvest time was 5 days after the initiation of cultivation for both types of thick bean sprouts. The total amino acid contents was markedly decreased in the both types of thick bean sprouts compared with beans as a raw material (dry matter). The total amino acid contents began to gradually increase in the early phase of cultivation and markedly increased, reaching a peak, in the middle phase of cultivation (after 3-5 days). This increase was marked in the order of DPSL>DMP>CRC>Control. In the cultivation process of both types of thick bean sprouts by each cultivation method, marked increases were observed in Met, Cys, Phe, Tyr, Thr, Trp, and Leu but slight increases in the other amino acid. Changes in amino acids during storage were similar to those in the cultivation process. The residual contents was the highest after 3 days storage at a temperature of 5±2°C or less. Both types of thick bean sprouts by showed the highest total quality at the time of consumption in terms of extension and appeared to be of value as a material the provides protein and amino acids.