有色糯性糜子理化与体外消化特性研究

以不同颜色糯性糜子为实验材料,黄色硬糜子为对照,分析比较了4种糜子理化和体外消化特性。结果表明,4种糯性糜子淀粉、粗蛋白质、脂肪、直链淀粉的质量分数平均为70.56%、11.73%、3.92%、1.83%;4种糯性糜子的亮度指数没有显著差异,红绿值和黄蓝值有差别;白糜子的溶解度和膨胀度最大,红糜子最小;4种糯性糜子的多酚、黄酮含量差异不显著;与80℃蒸煮相比,100℃蒸煮后的糯性糜子米粒较为黏稠,硬糜子米粒比较松散,各项蒸煮指标均有明显增加;4种糯性糜子的起糊温度、峰值黏度、破损值、最终黏度和回生值均低于黄色硬糜子,其中红糜子具有较高的起糊温度,黑糜子的回生值最大;黄糜子快速消化淀粉质量分数最高为59.51%,黄色硬糜子消化速度慢于4种糯性糜子。     

The Use of Response Surface Methodology to Optimise Malting Conditions of Proso Millet (Panicum miliaceum L.) as a Raw Material for Gluten‐Free Foods

Response surface methodology was used to investigate the influence of the three malting parameters, i.e. degree of steeping, germination time, and temperature on the quality of proso millet malt. Each predictor variable was tested at three levels. Germination times varied from 5, 6, and 7 days, degrees of steeping were 44, 48, and 52%, and germination temperatures were 16, 20, and 24°C. A set kilning temperature of 65°C was used for all malts. A series of malt quality parameters were investigated including extract, apparent attenuation limit, gelatinisation temperature, α‐amylase activity, β‐amylase activity, limit dextrinase activity, Kolbach index, α‐amino nitrogen, viscosity, and colour. The optimal malting program was achieved after the fifth day of germination, 44% degree of steeping, and a 22°C steeping and germination temperature. The obtained values for the amylolytic and cytolytic attributes were 64.8% extract, 1.383 mPa × s viscosity, 76.0% apparent attenuation limit, 111 U/g α‐amylase activity, and 102 U/g β‐amylase activity.     

Proso millet (Panicum miliaceum L.): An Evaluation of the Microstructural Changes in the Endosperm during the Malting Process by Using Scanning‐Electron and Confocal Laser Microscopy

Scanning electron microscopy (SEM) and confocal scanning laser microscopy (CLSM) were used to investigate the micro‐structural changes in the endosperm during the malting process. SEM was a suitable tool to characterise the microstructural constitution of starch granules in proso millet and the changes occurring during malting. An early visible degradation (after 24 h) of starch granules located in the floury endosperm, which is close to the embryo, could be observed. Due to this degradation, using confocal scanning laser microscopy, a less dense packaging of this part of the endosperm was observed. Degradation of starch granules in the vitreous endosperm was obvious at a distinct later stage of malting (78 h) and a preferred attack of small granules (>2.5 μm) was detected. Changes in protein structure could not be detected by either SEM or CLSM.     

Studies on the mashing conditions of teff (Eragrostis tef) malt as a raw material for lactic acid‐fermented gluten‐free beverage

Formation of extracts and fermentable sugars during mashing can be limited by incomplete starch gelatinisation. The aim of this research was to develop mashing programme for 100% teff malt as a potential raw material for gluten‐free lactic acid‐fermented beverage. Isothermal mashing at temperatures ranging between 60 and 84 °C was conducted, and the highest extract (85%) was observed for the wort samples produced at temperatures higher than 76 °C. Sixty‐minute rest at 71 °C resulted in higher fermentable sugars than other tested conversion rest temperatures. Inclusion of lower mashing‐in temperature in the mashing programme also substantially improved the concentrations of free amino nitrogen (128 mg L^?1) and fermentable sugar (58 g L^?1) in the final wort. Therefore, 30‐min rest at 40 °C followed by 60‐min rest at 71 °C and 10‐min rest at 78 °C was found to be a suitable mashing programme for teff malt.