含水量和处理温度对人工加速老化试验中水稻种子储藏特性的影响

为了克服已有的高温高湿的人工老化方法受人工气候箱的控温控湿条件的局限性,以确保试验过程中种子含水量和温度的稳定性,本文研究在人工气候箱环境材料间开放和密闭的条件下水稻种子含水量随处理时间的变化规律;进而研究密闭常湿条件下处理30 d的不同温度、不同含水量籼粳材料种子发芽率变化。结果表明,与初始含水量范围相比,储藏过程中粳稻材料和籼稻材料的含水量范围,30℃+RH 75%、30℃+RH 85%的开放储藏条件下,分别缩小为原来的31%和24%、26%和25%,而30℃+常湿、34℃+常湿的密闭储藏条件下,则仅分别缩小为原来的94%和81%、90%和87%; 38℃+常湿+30 d、42℃+常湿+30 d的密闭储藏条件下,初始含水量差异的粳稻和籼稻材料,发芽率差异最高和最低分别为85.0%和7.0%、98.5%和11%;进一步计算种子人工加速老化处理30 d的发芽率下降百分率,38℃+常湿、42℃+常湿的密闭储藏条件,初始含水量14.00%的粳稻材料和籼稻材料,其发芽率下降百分率已分别达到63.31%和88.83%。初步分析获得:38℃+常湿+初始含水量14.00%+30 d+密闭储藏、42℃+常湿+初始含水量14.00%+30 d+密闭储藏分别是粳稻和籼稻人工加速老化试验最适宜的处理条件。本研究为获得稳定的、可重复的人工加速老化新方法提供理论参考。     

人工加速老化对小麦种子CAT、POD、SOD活性和可溶性蛋白质含量的影响

为探明小麦种子在种子贮藏过程中的生理生化变化的规律及合适的老化处理条件,采用高温高湿人工加速老化的方法,对5个非糯小麦和5个糯小麦品系的种子在90%相对湿度和40、45、50、55、60℃条件下分别处理0、2、4、6和8 d,结果表明:SOD、POD和CAT活性在较低温度处理下呈升高、而较高温度处理下则呈下降趋势;可溶性蛋白质含量在45℃处理下降低,但在50℃处理下升高。研究表明,小麦以90%的相对湿度和55℃的高温处理能在较短的时间内达到最佳的老化效果。     

模拟典型储粮环境下大米品质指标的变化及其差异性分析

为了探讨中国典型储粮环境下大米储藏品质指标的变化规律及其影响因素,选择籼型和粳型商品大米各1种,采用可编程人工气候箱进行模拟储藏,定期测定样品的脂肪酸值、α-淀粉酶活性、过氧化物酶活性、电导率等指标.然后,采用SPSS16.0统计软件对测定数据进行差异性分析.结果表明:储藏温度在20℃以下时,温度和湿度对脂肪酸值和α-淀粉酶活性影响不显著,但当温度高于20℃时影响显著,且温度越高影响越显著.大米类型对脂肪酸值和α-淀粉酶活性的变化也有一定的影响;储藏温度和湿度以及大米类型对电导率的变化影响不显著,储藏时间影响显著;温度对过氧化物酶活性影响显著,变化的温、湿度对其影响更显著,在15℃低温条件下湿度对其影响在储藏3个月后显著;各指标与储藏时间均高度相关.     

储藏温度对稻米淀粉糊化特性的影响

为研究稻谷储藏温度对稻米淀粉糊化特性的影响,用人工气候箱将早籼稻谷在5、15、25、35℃条件下储藏12个月。分析测定了不同温度储藏稻米淀粉的提取率、色泽、溶解度、润涨力、糊化特性及淀粉凝胶的质构特性。结果表明,相对于新收获稻米,经35℃储藏稻米提取的淀粉色泽微黄,淀粉提取率降低了19.65%;5℃储藏稻米淀粉在90℃时的膨润力最大,经储藏处理稻米淀粉在80℃和90℃的溶解度均高于新收获稻米;稻米淀粉的糊化温度和淀粉凝胶的硬度随储藏温度升高而增加,淀粉的峰值黏度和最终黏度及淀粉凝胶的黏聚性随储藏温度升高而降低。     

玉米脂肪氧化酶缺失种质耐储藏特性的研究

采用人工加速陈化的方法研究脂肪氧化酶同功酶（LOX—1，2）缺失对玉米种子储藏过程中陈化的作用。三个F1代种子：农大高油115，豫玉25号和JKF1（LOX—1，2缺失），在温度42℃，相对湿度84％的智能人工气候箱中放置15天，调查了种子的发芽率，电导率，丙二醛。结果表明：随着储藏期的增加，电导率、丙二醛表现出上升的趋势；在加速老化过程中，种子发芽率呈下降趋势，但是LOX—1，2缺失的JKF1，至实验结束，发芽率几乎没有变化，仍保持在96％；发芽率的下降和电导率的增加呈很好的相关性。由此表明LOX-1，2可能是影响种子寿命的关键基因。     

乳化剂及保藏温度对小米馒头贮藏过程老化的影响

以糊化度为评价指标,研究在37、20、4、-20℃下,1~30 d内小米馒头的老化程度及速率;分析不同保藏温度对其老化的影响。选择单硬脂酸甘油酯(GMS)、硬脂酰乳酸钙钠(CSL-SSL)和蔗糖脂肪酸酯(SE)3种食品乳化剂,以0.1%的添加量加入小米粉中,研究储藏过程中乳化剂对小米馒头老化的影响,评价其抗老化作用以及乳化剂与温度协同抗老化效果。结果表明:4℃的冷藏条件小米馒头老化剧烈,老化速率最大;高温虽能短期内表现出良好抗老化性,但-20℃冷冻储藏更适宜小米制品的长期储藏。3种乳化剂均能表现出良好抗老化特性;短期放置,20℃室温+GMS抗老化效果最佳;长货架期放置,-20℃冷冻条件+SE抗老化作用最显著。     

储藏温度对稻米淀粉糊化特性的影响

为研究稻谷储藏温度对稻米淀粉糊化特性的影响,用人工气候箱将早籼稻谷在5、15、25、35 C条件下储藏12个月.分析测定了不同温度储藏稻米淀粉的提取率、色泽、溶解度、润涨力、糊化特性及淀粉凝胶的质构特性.结果表明,相对于新收获稻米,经35℃储藏稻米提取的淀粉色泽微黄,淀粉提取率降低了19.65％;5℃储藏稻米淀粉在90℃时的膨润力最大,经储藏处理稻米淀粉在80℃和90℃的溶解度均高于新收获稻米;稻米淀粉的糊化温度和淀粉凝胶的硬度随储藏温度升高而增加,淀粉的峰值黏度和最终黏度及淀粉凝胶的黏聚性随储藏温度升高而降低.     

航道用聚丙烯土工织物的老化性能研究

针对航道治理工程的使用环境开发了防老化聚丙烯复合土工织物。通过人工加速老化试验、大气自然老化试验、水下实地老化试验对所开发产品的老化性能进行研究和评价     

不同储藏条件对小麦粉糊化特性的影响

对不同储藏条件下,小麦粉糊化特性进行了研究。设置储藏温度为20℃(常温)、35℃(高温),储藏湿度分别为45%、55%、65%、75%、85%,进行了小麦粉的模拟储藏试验。结果表明:小麦粉峰值黏度与最终黏度随温湿度的增高、储藏时间的延长而变大,储藏湿度与储藏时间对其影响显著;小麦粉衰减值与回生值随储藏温湿度的提高、储藏时间的延长变化总体较小,但在高湿条件下有明显的下降。     

乳化剂抑制鲜湿面货架期内品质老化机理研究

研究探析乳化剂抑制鲜湿面货架期内品质老化的机理,利用差示扫描量热仪(DSC)分析了硬脂酰乳酸钠(SSL)添加组,β-环糊精(β-CD)添加组鲜湿面以及经脱蛋白或脱脂处理后的鲜湿面的热力学变化。结果表明:未处理组的鲜湿面,在4℃储藏14d后,第一个支链淀粉峰SSL和β-CD添加组的老化焓△H都低于CK组(P0.05);第二个复合物峰SSL和β-CD添加组的重结晶融化温度Tp和老化焓△H都高于CK组(P0.05);鲜湿面经脱蛋白处理组,在4℃储藏14d后,相比未处理组支链淀粉老化焓稍有增大但无显著差异;第二个复合物峰的重结晶融化顶点温度显著升高,老化焓也稍有增大,但变化也不显著;经脱脂组鲜湿面储藏14d后,相比未处理组支链淀粉热力学特征无显著差异;第二个复合峰重结晶融化顶点温度和老化焓都显著升高(P0.05)。两种乳化剂均能干扰直链淀粉与脂类的结合,形成直链淀粉-乳化剂-脂质络合物,抑制鲜湿面货架期内品质老化。     

Superior storage stability in low lipoxygenase maize varieties

The present study was carried out to investigate the effect of absence of lipoxygenase isoenzymes (LOXs) on deteriorative changes in seeds of maize (Zea mays L.) using accelerated ageing. Three varieties of maize seeds, nongda high-oil 115 and zhengdan 94-2 with LOX-1, 2 and ZAF1 lacking LOX-1, 2, were stored at 42±1 °C and 84% r.h. for a period of 15 d. Standard germination, electrical conductivity, as well as malondialdehyde tests were used to follow changes during accelerated aging tests. The results indicated that germination of all tested seeds decreased with advanced ageing while electrical conductivity of the seed-soaking solution increased. Percentage germination was correlated with increased accumulation of malondialdehyde content. For the variety lacking LOX-1,2, there was a slight change in germination during the 15-d accelerated aging experiment, but for varieties with LOX-1, 2, a decline in germinability was observed, suggesting that LOX-1, 2, may be a definitive factor which influences seed lifespan.     

糙米发芽过程中抗坏血酸的生成特性

研究了糙米发芽过程中抗坏血酸的生成特性,并就生成特性与稻米品质的相关性进行了初步探讨,研究结果表明:(1)稻谷的干种子中几乎不存在抗坏血酸,在发芽过程中逐渐生成,AsA的生成在发芽实验中有增减变化,DasA则呈现单调增加趋势。(2)糙米的陈化程度对抗坏血酸的生成有影响,陈化抑制了抗坏血酸的生成。(3)抗坏血酸的生成特性能更好的表达稻米陈化过程中食味的变化。     

贮藏温度和时间对籼稻糊化特性的影响

研究了3种籼稻(浙富802、元隆8462与早籼5-34)在不同贮藏温度(36,25,4℃)和时间(0~3个月)下的糊化特性变化。结果表明,当贮藏温度为36℃时,贮藏时间与籼稻糊化特性显著相关(P<0.05),表现在籼稻的峰值黏度和崩解值均先上升后下降,冷糊黏度先上升后趋于稳定,回生值和糊化温度均上升,但变化时间点和程度受籼稻品种的影响。当贮藏温度为25℃时,籼稻糊化特性指标中除回生值和糊化温度未发生显著变化(P>0.05)外,其他指标的变化趋势与36℃时的基本一致,但变化时间明显滞后36℃。4℃贮藏对籼稻的糊化特性无显著影响(P>0.05)。说明,36℃可以作为籼稻加速陈化的温度,加速陈化的换算时间跟籼稻品种有关;4℃则可以作为对照组。     

微波加速陈化过程中大米理化性质和组织结构的变化

新收获稻米的食用品质不佳,经过自然陈化(3~6个月)可以改善米饭的口感,而采用物理方法不仅能加速稻米陈化还能节省陈化时间,降低仓储成本。本研究采用微波(540 W处理30~50 s)处理稻米,并分析大米糊化性质、质构特性和组织结构的变化。结果显示,微波处理后大米的最终黏度、回生值显著增加,米饭的硬度增加,黏度下降,表明微波处理加速了大米的陈化。组成分析显示,微波处理后大米蛋白质的二硫键增加,同时发现米粒断裂面上的胞间断裂减少,胞内断裂增加,表明微波处理降低了胚乳细胞壁的机械强度。此外,与自然陈化过程中游离脂肪酸含量逐渐上升的变化不同,微波处理后大米中的游离脂肪酸含量降低,可减少哈败味的产生。这说明适度的微波处理可以加速稻米陈化,抑制稻米的哈败味产生,且微波处理的稻米陈化与胚乳细胞壁和二硫键的变化有关。     

The application of 20 kHz ultrasonic waves to accelerate the aging of different wines

Two different kinds of wine, one made from rice material and the other from maize material, were aged using 20 kHz ultrasonic waves (accelerated aging), which is widely used commercially. These two kinds of wine were also aged for 1 year in fired clay containers (standard aging, a standard conventional aging time in Asian market of rice wine). Comparisons of pH value, alcohol content, gas chromatography measurements, sensory evaluation and the time of aging were made between the two different aging processes on each of the wines. Results showed that the 20 kHz ultrasonic waves treatment aged rice wine much more quickly than standard aging, with similar quality, but did not age maize wine with comparable quality. The 20 kHz ultrasonic waves treatment has potential as a good alternative method of aging wine made from some materials but not all.     

米粉陈化中各宏量组分对糊化特性变化的贡献

为揭示稻米在储藏中的陈化机理,进而改善米及制品的品质,研究了米粉陈化中各组分对其糊化特性的影响。以米粉为原料,糊化特性参数为指标,排除米中宏量组分自身基质效应的影响,分离出各组分单纯的陈化效应,通过组分陈化贡献率比较了各组分对糊化特性变化的贡献。结果表明,米粉陈化后清蛋白对糊化特性的影响与陈化前刚好相反,对糊化特性变化的贡献率最大,达到83%,其次影响较大的是淀粉和脂肪,而谷蛋白和醇溶蛋白在一定程度上抑制了陈化,球蛋白的影响很小。可见,各组分对陈化的影响差异很大,且不是所有组分都对陈化有促进作用。研究清蛋白在陈化中的变化将是揭示米粉陈化机理的重要途径,对于控制米及制品的品质具有重要意义。     

Study of ultrasonic wave treatments for accelerating the aging process in a rice alcoholic beverage

This research focussed on the accelerated aging of a rice alcoholic beverage by applying two different levels of ultrasonic power. The rice alcoholic beverage was fermented with Saccharomyces sake. The control treatment was aged for one year in fired clay containers (standard aging) while two other treatments simulated aging by using 20 kHz and 1.6 MHz ultrasonic waves, respectively (accelerated aging). Comparisons were made of alcohol content, titratable acidity value, gas chromatography measurements of volatile aroma compounds, sensory evaluation and time of aging. Results showed that the 20 kHz treatment influences rice alcoholic beverage aging better than the 1.6 MHz treatment. The 20 kHz ultrasonic wave treatment has potential as a good alternative method for aging the alcoholic beverage. Further studies are needed to elucidate the best power range of ultrasonic waves for aging alcoholic beverages made of various materials.     

Effect of the absence of lipoxygenase isoenzymes on the storage characteristics of rice grains

Three varieties of paddy rice with and three varieties without lipoxygenase (LOX) isoenzymes were stored at room temperature, in dark conditions for 42 months. Insect damage and viability were investigated during that time. Varieties without LOX-1,2 and their offspring were screened with a rapid method of estimating LOX isoenzymes, and subjected to an accelerated-ageing experiment. The results indicated that in varieties without LOX-1,2, after long storage, rice quality was normal, but for varieties with LOX-1,2, rice quality deteriorated. With increase of storage time, the germination rate of the seed of most varieties decreased greatly except for varieties without LOX-1,2 where there was almost no change in the germination rate. In varieties without LOX-1,2 and their offspring, after an accelerated ageing experiment the germination rate of some varieties changed slowly, but with others, the germination rate changed quickly. This indicated that a definitive factor, which influenced the life of seeds, may be the loss of LOX-1,2. During storage, there was also a significant difference in the degree of insect damage. In varieties without LOX-3 insect damage was lower, but in varieties with LOX-3 insect damage was higher. Therefore, the absence of LOX-3 may be very important in insect resistance in rice grain.     

OPTIMIZATION OF PROCESS VARIABLES FOR ACCELERATED AGING OF BASMATI RICE

ABSTRACT

Experiments were conducted to develop a process for accelerated aging of aromatic rice. Freshly harvested clean paddy of “Pusa Basmati” variety was conditioned as per the experimental design. Response surface methodology for three variables at five levels was used. Central composite rotatable design was used to optimize the temperature (30–50C), relative humidity (50–90%) and aging period (3–14 days) to accelerate the aging process for paddy. The optimum levels of process variables were based on the desired milling and cooking quality indices. The quality attributes included milling yield, kernel elongation ratio, volume expansion ratio, solid loss, amylose content, gel consistency and aroma. A complete second‐order polynomial model was fitted to the data and the adequacy of the model was tested. The models were then used to interpret the effect of various input parameters on the response. The total effect of individual input variables and combined effect of all these variables at linear and quadratic level on head yield was significant at 1% level. Similar interpretation of the effect of various input parameters on the responses have been done in details. The common optimum condition for accelerated aging of paddy was found to be 43.4C, 71.0% relative humidity (RH) and 11.4 days.

PRACTICAL APPLICATION

Freshly harvested rice is less preferred by consumers because of poor cooking properties like less kernel elongation and volume expansion ratio with more solids loss and softer gel consistency. Aging brings about progressive desirable changes in the grain. The natural aging process is time‐consuming and also requires proper storage. Therefore, the aging process may be accelerated by subjecting the grains to appropriate environmental conditions to bring about the acceptable properties so that the full potential of domestic as well as export market may be explored at the right time with a relatively high price. The information obtained from this study may be used in designing thermal processing to obtain aged rice within a short period.     

中国黄酒中香草醛的定性定量分析

采用液-液微萃取结合气相色谱-质谱联用方法对不同黄酒中香草醛进行了定性定量分析,用香气活力值法分析了香草醛在黄酒中的香气贡献,并对黄酒贮存过程中香草醛的变化规律进行了分析。研究结果表明:新酒中香草醛的含量低于市售成品酒的含量,普通市售成品酒中香草醛的浓度低于同品种高档酒中的浓度;在所研究的黄酒中,香草醛的香气活力值均大于1;香草醛主要来源于黄酒贮存过程,并且其含量随着黄酒贮存时间的延长而增加。结论是:液-液微萃取结合气相色谱-质谱联用方法能有效地分析黄酒中香草醛的含量,香草醛是黄酒中有重要贡献的香气化合物,贮存过程有利于黄酒中香草醛的形成。