Effect of audio wave on production of soybean sprouts in small box

Abstract: Audio fostering technology has been regarded as one of the most efficient and environmental-friendly physical methods for agriculture in the 21st century. However, this technology is still in the early stage of exploration. Soybean sprouts are a type of traditional Chinese vegetable. It has not only delicious taste and beautiful appearance, but also rich nutrient, no cholesterol, low fat and high protein. To improve the production of soybean sprouts and shorten the production cycle, growth hormone or chemically synthesized hormones were added by some manufacturers in the growth of soybean sprouts, resulting in food safety problems. The application of audio wave to plant can change the cell membrane structure, which will enhance the flow and permeability of the cell membrane and promote the growth and division of the cells. Also, it can promote the absorption and accumulation of various nutrients during the transport and transformation process. Crops, vegetables and fruits have been fostered by audio and good results have been achieved. However, the consensus about the mechanism of audio fostering on plant growth hasn't been reached in scientific community because of insufficient experiment support. To provide a scientific basis for the application of audio fostering technology in the production of soybean sprouts, the impact of the technology on yield and quality of soybean sprouts in small box cultivation was investigated based on soybean sprouts production technology, combined with soybean sprouts physiological characteristics, and environment and equipment requirements. The soybean sprouts production process was 1-2 min in 60 ℃ hot water, soaking in 30-35 ℃ water for 5 h, then packed in small box (120 g), stacked in 25-30 ℃ dark workshop, and fostered by audio for 4 d with 1 spray every 3 h, and finally maintained at 5 ℃ for cold storage. Five workshops with the same temperature and humidity conditions were selected. Five types of music (piano solo, Chinese classical music, rock and roll, pop music and single frequency soundwave), 5 kinds of music playback time (2, 3, 4, 5 and 6 h) and 5 music playback volumes (50-60, >60-70, >70-80, >80-90 and >90-100 dB) were chosen. According to the single factor test results, three-factor and three-level orthogonal experiment was carried out. The optimal conditions were >70-80 dB piano solo music played for 5 h per day. Under the above conditions, the soybean sprouts yield was 1.361 kg/100 g, while the yield of the control was 1.078 kg/100 g. Therefore, the yield of soybean sprouts was increased by 26.25% after optimization of audio fostering conditions including types of music, playback time, and playback volume. Among the 3 factors, the type of music had the greatest impact on the growth of bean sprouts. Small box cultivation with audio fostering technology successfully increased the yield, shortened production time and improved the food safety. The results show that the audio fostering technology can promote the growth of bean sprouts, which can provide the theoretical basis for the popularization and application of the audio fostering technology in the production of bean sprouts. In addition, the essential mechanism of biological effects of audio fostering technology needs further research.