Accumulation Of Γ-Aminobutyric Acid And Preservation Of Mung Bean (Vigna Radiata L.) Sprout

As a traditional crop, mung bean (Vigna radiata L.) is rich in nutrient value and widely cultivated in China. During the processing of sprouting, original nutrients are consumed, ant-nutritional factors are transformed into other forms which could be absorbed easily. γ-aminobutyric acid (GABA) can be accumulated in germinated bean at the same time. By controlling the germinating condition (pH, temperature and hypoxia stress time) and culture solution components (NaCl, VB6 and CaCl2), the optimal culture condition and culture solution components to accumulate GABA were obtained. Subsequently, the nutritional changes of mung bean during germination were investigated.Mung bean sprout is a traditional food with high moisture content and crisp. However, the sprouts are brittle and short in shelf life, leading to low profits in sales. Hence, the effects of temperature and punching number on quality and GABA content of mung bean spourts during storage were evaluated. After optimizing the scalding time, citric acid concentration and sauce ratio, a soft canned package method for mung bean sprouts was developped.1. Orthogonal experiment was used to optimize the germinating conditions (pH values, temperature and hypoxia stress time) and components of the culture solution (NaCl, VB6 and CaCl2). The optimal level was:pH 5.0,30℃,24 h hypoxia stress time with the addition of 30 mmol/L NaCl,70μmol/L of VB6, and 10 mmol/L of CaCl2. During 120 h of mung bean germination, the length of spourts, free amino acid, reducing sugar and GABA content increased while the soluble protein increased firstly and then decreased.2. Quality changes of mung bean sprouts during storage under different storage temperatures and punching numbers of packaging were studied. The weight loss rate and respiration rate of mung bean sprouts changed with different temperatures and punching numbers. The results showed that temperature and punching number not only affected the physiological quality, but also affected the GABA content.3. The effects of scalding time and citric acid concentration on the browning degree, polyphenol oxidase activity, shear force and weight loss of mung bean sprouts were studied by single factor test. The sauce ratio of soft canned mung bean sprouts was optimized by orthogonal test. Results suggested that the optimal process conditions were 2 min scalding and 1% citric acid content, the best formula of soft canned mung bean sprouts were 4% vinegar,1.5% salt,9% spicy oil and 1% capsicum powder.