Research On Characteristics Of Nutrition And Biochemistry Of Germinated Unpolished Coix Seed And Its Extension Products

Coix seed(Coix lachryma-jobi L.), as a kind of edible and pharmacodynamic minor cereals, combining the feature of nutrition, medical care, and health care, is not only rich in protein, fat, carbohydrates, vitamins, minerals and other nutrients, but also contains coixan, coixenolide, coixol, triterpene compound and other functional components. And it possesses significant effects in anti-tumor, anti-oxidation, in vigorating the spleen to eliminate dampness, clearing away heat and eliminating pus and maintaining beauty. So it was known as "The Coix Pearl" in ancient China and called "The Hygroryza of Healthy" in Europe. In recent years, it had been really welcomed by consumers and had enormous market potentials. In order to develop new coix seed products with high nutrition and health value, 5 samples of unpolished coix seeds which were planted in Guizhou and Laos were used as raw materials. Meanwhile, the dynamic changes of physiological and biochemical indexes and nutritional composition were compared under the same germination condition to select a certain kind of unpolished coix seed which is suitable for germinating. The germination rate and the content of γ-amino butyric acid(GABA) were tested as the indexes and the orthogonal design methods was used to optimize germination condition of the optimum unpolished coix seed and to detect the dynamic changes of its main nutritional and components. By using germination rate, the content of selenium and γ-amino-butyric acid as the important indicators, the response surface methodology(RSM) was used to optimize concentration of Na2SeO3, CaCl2, gibberellin(GA3) and monosodium glutamate(MSG) under the optimization temperature and humidity conditions. Moderately germinated unpolished coix seed were dried in air, then, undergone freezing, vacuum and hot air, respectively. Finally it was ground to pre-cooked unpolished coix seed new products. The rehydration characteristic, nutrition and function were compared. The results showed that:1. Among the 5 kinds of testing unpolished coix seed, The GZ-1 had highest germination rate, with highest content of free amino acids and γ-amino butyric acid. The optimal germination condition of GZ-1 were 28°C of temperature, 90% of relative humidity, 96 h of germination time, the content of γ-amino butyric acid was up to 78.18mg/100 g. During 144 h germination, the content of protein, starch and polysaccharides gradually decreased while the content of reducing sugars, free amino acids, γ-amino butyric acid, and vitamin C, B1 and B2 gradually increased. But the coixenolide content almost unchanged. To analyze the amino acid of unpolished coix seed under optimum germination conditions, the content of essential amino acids and total amino acid were higher than the raw material. Also, the amino acid score was equal to 1, indicating that its nutritional value was higher than the raw material. Therefore, it’s a better functional food base material with higher nutritional value and biological activities.2. The best Na2SeO3 concentration of germinated unpolished coix seed was 10mg/L, which has the highest germination rate was up to 90.33±1.73%. Using this culture medium and adding the optimal reagents determined by RSM(Na2SeO3 10mg/L, CaCl2 11mmol/L, GA3 87.7μmol/L and MSG 31.5mmol/L), the content of total selenium, organic selenium and γ-amino butyric acid of germinated unpolished coix seed were up to 0.42 mg/100 g, 0.37mg/100 g and 116.69mg/100 g. Therefore, it’s a health food base material with high-value potential.3. Among the new products of pre-cooked coix seed made by germinated unpolished coix seed, freeze-dried product have the best quality: rehydration rate of 2.1107, good color(L* 62.73, a *4.40, b* 12.61)and the content of γ-amino butyric acid was up to 86.06mg/100 g. Its soluble protein and free amino acids have significantly improved which were 1.68% and 0.24%, respectively. It also had 8 kinds of essential amino acids, in which, the content of leucine is up to 13.43mg/g. Tthe content of unsaturated fatty acid is 84% in 9 kinds of fatty acids, while, the content of oleic acid is up to 49%. Moreover, the sensory score was best when cured at the condition of mild boiling at 95~100°C for 30 min, which is also easy to get cooked and have good taste.