| Oat(Avena sativa L.) is ranked sixth highest in planting area and yield among all cereal crops. Its particular chemical composition and physiological activities offer high nutritive value for both human and animal. Unlike the common oat, naked oat which is also called Youmai and characterized by hulless seeds is an endemic type in China. Oat industry has developed with the trend of growing interest in functional food among consumers. However, lack of rapid detection method, special variety and processing innovation restricts the development of oat industry. This study investigated the FT-NIR method development and variance analysis of quality traits as well as processing optimization, aroma composition and nutritional evaluation of Chinese Oat Wine.1. Calibration models were developed from FT-NIR spectra and chemical-method determining values for the estimation of quality traits in naked oat from an initial set(147 naked oat samples). The optimized models of protein, starch, lipid, β-glucan and avenanthramides in whole grain/milled samples indicated coefficients of determination(R2) of 0.98/0.98, 0.97/0.98, 0.97/0.97, 0.98/0.98, 0.90/0.90 and root mean square error of cross validation(RMSECV) of 0.40/0.35 %, 0.59/0.52 %, 0.27/0.24 %, 0.09/0.06 % and 60.4/59.2 mg/kg. Test validations achieved with root mean square error of prediction(RMSEP) of 0.46/0.40 %, 0.68/0.63 %, 0.26/0.26 %, 0.10/0.09 % and 47.7/46.3 mg/kg with residual predictive deviation(RPD) of 5.38/6.30, 5.07/5.15, 6.06/6.24, 5.13/6.17 and 3.37/3.56. These findings showed that FT-NIR could be used as a rapid and accurate method for selecting higher quality naked oats in a breeding programme as well as for quality control by the food processing.2. Nine cultivars were planted at fifteen different environments to investigate the effect of genotype, environment and their interaction on quality traits in naked oat. Wide ranges of concentrations were observed and all the parameters were significantly affected by the genotype, environment and their interaction. Environment variance was predominant in the total variance of protein, starch and avenanthramides contents(89.14%, 81.06% and 82.33%) while cultivar accounted for 79.52% in lipid content variance. In addition, variance caused by cultivar and environment in β-glucan content were approximate(30.44% and 29.10%). Geographical coordinates significantly affected the protein, starch, lipid and β-glucan contents. Starch and lipid content had highly significant and negative correlations with protein content. β-glucan content was positively correlated with protein content but negatively with starch content. With appropriate values of nutrient components, some samples can be selected as raw materials for industrial production or parents in naked oat breeding for health benefit.3. Taking roasted and milled naked oat as raw material for producing Chinese oat rice wine, the optimization of processing conditions was investigated by single-factor experiments and orthogonal tests based on dextrose equivalent as well as reducing sugar and solid content. Results showed that the optimal liquefaction condition was thermostable α-amylase addition of 5 U/g, liquefaction temperature of 95 ℃ and liquefaction time of 40 min. The optimal saccharification condition was glucoamylase amount of 100 U/g, saccharification temperature of 65 ℃ and saccharification time of 180 min. And the optimal main fermentation condition was yeast inoculation size of 0.25%, ratio of material to water of 1:3.5, fermentation temperature of 30 ℃ and fermentation time of 5 d. Under these conditions and after stabilization(16 ℃ and 30 d), oat Chinese rice wine was obtained.4. The aroma characteristics of Chinese oat wine was investigated using headspace solid phase micro-extraction and gas chromatography-mass spectrometry. A total of 55 aroma components were identified, which were composed of 14 kinds of aromatic compounds, 6 kinds of alcohols, 15 kinds of esters and 22 kinds of others. The aroma compounds in high content were phenylethyl alcohol and 3-methyl-1-butanol. BHA and BHT were also detected which suggested that Chinese oat wine might have anti-oxidant activity.5. To evaluate the amino acid and total polyphenol content as well as antioxidant activity of Chinese coarse cereal wine. With national standard method carried, amino acid composition was analyzed. Total polyphenol content was measured by Folin-Ciocalteu assay. Antioxidant property was evaluated by 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical and 2,2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt(ABTS+?) scavenging assays as well as oxygen radical absorbance capacity(ORAC) assay. The amino acid content of Chinese foxtail millet wine was the highest while Chinese millet wine was the lowest. Total phenolics content showed a decreasing order from Chinese quinoa wine, Chinese foxtail millet wine, Chinese oat wine to Chinese millet wine correspondingly. As to antioxidant activity evaluation, Chinese quinoa wine showed stronger DPPH free radical reducing capacity than others. Chinese foxtail millet wine exhibited the strongest antioxidant capacity in ABTS+? scavenging assays and ORAC assays. Chinese rice wine made by foxtail millet, oat, and quinoa exhibit great advantages than the traditional one in terms of amino acid content and antioxidant property. These coarse cereals can be raw materials for Chinese rice wine making. |
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