共查询到19条相似文献，搜索用时 265 毫秒
1.
在糙米碾米过程中普遍存在碎米较多及碾米能耗高的问题,为改善糙米碾米品质,提出以纤维素酶和木聚糖酶的复合酶溶液处理替代常规水加湿方法的酶法预处理工艺。以贮藏期糙米(含水率15%以下)为原料,采用二次正交旋转中心组合设计试验,研究复合酶溶液处理工艺中复合酶配比、酶质量浓度、加液量及酶处理时间对碾米后整精米率和碾米能耗的影响规律,建立了各因素对整精米率和碾米能耗影响的数学模型。结果表明:构建的整精米率、碾米能耗与复合酶配比、酶质量浓度、加液量及酶处理时间之间的回归方程极显著(P0.01),得到优化参数组合为纤维素酶和木聚糖酶质量比1.3∶1 g/g、复合酶溶液质量浓度65 mg/m L、加液量1.25%,酶处理时间102 min,该条件下整精米率为80.07%、碾米能耗为90.72 k J/kg。复合酶溶液处理后整精米率较加湿调质处理提高约3.98%,节约能耗约13.06%;较纤维素单一酶溶液加湿处理后整精米率提高约0.98%,节约能耗约5.48%。并通过微观结构分析证实了糙米皮层粗纤维的局部破损是其碾米性能改善的主要原因。研究结果可为实际生产条件下的酶法糙米预处理工艺提供参考。 相似文献
2.
循环加湿工艺降低发芽糙米爆腰增率并提高得率 总被引：3，自引：3，他引：0
为解决传统浸泡工艺制取发芽糙米过程爆腰率过高等问题,提出以循环加湿替代传统浸泡的一种发芽糙米生产新工艺。该研究以糙米为原料,采用二次正交旋转中心组合设计试验,研究循环加湿工艺中单次加湿量、间隔时间和温度对爆腰增率和发芽糙米得率的影响规律,建立了各因素对爆腰增率和发芽糙米得率影响的数学模型。用Excel软件和Design Expert软件处理试验数据,结果表明：单次加湿量、间隔时间和温度对爆腰增率和发芽糙米得率影响显著,得到优化参数组合为：单次加湿量1.2%～1.6%、间隔时间45～75 min、温度30℃,该条件下爆腰增率低于33%、发芽糙米得率大于90%。循环加湿处理后爆腰增率比传统浸泡处理降低20%～70%,发芽糙米得率提高1%～16%。研究结果可为改进发芽糙米生产工艺提供参考。 相似文献
3.
循环加湿工艺对发芽糙米中γ-氨基丁酸含量的影响 总被引：2，自引：2，他引：0
为提高发芽糙米中γ-氨基丁酸(GABA)含量,提出以循环加湿替代浸泡的一种发芽糙米生产新工艺。以东北粳稻为原材料,采用二次正交旋转中心组合设计试验,研究了循环加湿工艺中单次加湿量、间隔时间和温度对发芽糙米中GABA含量的影响规律,建立了GABA含量与各因素之间的数学模型,并以GABA含量为考核指标,将循环加湿工艺与浸泡工艺对比试验。试验结果表明,单次加湿量、间隔时间和温度对GABA含量影响显著(p<0.05),影响主次顺序为单次加湿量、间隔时间、温度,优化工艺参数为单次加湿量1.6%,间隔时间67min,温度31℃,此条件下每100g发芽糙米的GABA含量为27.33mg;循环加湿处理后发芽糙米中GABA含量为浸泡发芽处理的2.09倍。研究结果可为发芽糙米生产新工艺提供依据。 相似文献
4.
为进一步开发红叶李资源,筛选其活性成分,通过比较水煮沸、醇回流、超声、微波、闪式、超临界CO_2(SFE-CO_2)、复合酶酶解等提取方法对红叶李花中总黄酮含量的影响和对α-葡萄糖苷酶活性的抑制效果,确定最佳提取方法,并通过单因素试验和响应面法优选提取工艺。结果表明,复合酶酶解联合SFE-CO_2萃取工艺提取效率和生物活性最佳,SFE-CO_2萃取的总黄酮对α-葡萄糖苷酶抑制率达到96.09%,IC50为12.16μg·m L-1。最佳提取工艺为:酶解温度30℃,酶解时间3.5 h,酶用量0.10%,萃取压力30 MPa,乙醇浓度85%,萃取温度45℃,萃取时间60 min。此条件下的总黄酮得率为11.55%。本研究结果为红叶李花中总黄酮的开发与利用提供了技术参考。 相似文献
5.
发芽条件对发芽糙米中γ-氨基丁酸含量的影响 总被引：12，自引：3，他引：12
以糙米为原料，研究浸泡温度、发芽温度和发芽时间对发芽过程中γ-氨基丁酸(GABA)含量变化的影响，建立基于GABA含量的糙米发芽动力学模型，以获得富含GABA发芽糙米的最佳工艺条件。结果表明：浸泡温度、发芽温度和发芽时间对GABA的含量有显著影响，采用Logistic生长模型建立的糙米发芽动力学方程能较好地描述GABA含量的变化规律。在30～40℃浸泡和33～38℃发芽，GABA的增长速率常数b和积累极限k均达到较高水平；基于GABA含量的最佳发芽条件为33.0℃浸泡12 h，35.1℃发芽26 h，此条件下GABA的含量可达32.23 mg/(100 g)。 相似文献
6.
7.
超声波辅助酶法提取红腰豆多糖工艺优化 总被引：4，自引：7，他引：4
为了开发利用红腰豆多糖资源,该文探讨了超声波技术协同复合酶处理提取红腰豆多糖的工艺条件并对其结构进行了初步分析。在50℃下,以多糖得率为指标,通过正交试验筛选复合酶最佳配比,利用Plackett-Burman试验设计分析各因素显著性,再采用Box-Behnken中心组合设计原理进行响应面分析优化;采用紫外和红外光谱扫描及苷键分析对红腰豆多糖结构进行初步分析。结果表明:复合酶最佳质量配比为木瓜蛋白酶∶果胶酶∶纤维素酶=3∶1∶3。酶解p H值和超声功率对提取红腰豆多糖影响达到极显著效应,复合酶添加量和超声时间为显著因素。最佳工艺参数为液料比80∶1 m L/g、复合酶添加量4.0%、酶解p H值5.0、酶解时间1.5 h、超声功率400 W、超声时间34.0 min,红腰豆多糖得率为14.15%。经紫外和红外光谱扫描表明红腰豆多糖经DEAE-52纤维素层析柱和Sephadex G-200层析柱两步纯化后纯度较高,具有多糖的特征吸收峰;通过高碘酸氧化和Smith降解分析可推测红腰豆多糖的连接方式为α(1→4)和(1→6)连接。研究结果为酶法联合超声波处理技术在红腰豆多糖提取过程中的应用及其后续红腰豆多糖结构表征、生物活性等方面的研究提供理论依据。 相似文献
8.
玉米芯碱液预处理条件优化 总被引：10，自引：3，他引：7
该文对木质纤维素原料玉米芯碱液预处理条件进行了优化,以去除木质素,提高半纤维素、纤维素的酶解得率为目的。采用单因素多水平和正交试验方法得到最优预处理条件为：预处理时间12 h,温度70℃,液固比23︰1,反应液中各物质质量分数为氨水2.5%、过氧化氢 0.6%、硅酸钠5%、硫酸镁0.05%。在此最优条件下,玉米芯残渣得率为59.74%、半纤维素保留率为56.60%、纤维素的保留率为86.20%、木质素的保留率为11.83%。残渣经分步酶解（木聚糖酶和纤维素酶）,半纤维素、纤维素、总的酶解得率分别为41.36%、88.09%、69.21%,比未经预处理的玉米芯酶解得率分别提高了39.18%、40.89%、44.88%。结果表明,酶解得率与半纤维素的损失、木质素的去除有直接相关性。 相似文献
9.
速溶龙眼粉加工的酶解提取与喷雾干燥工艺优化 总被引：6，自引：1，他引：5
为了建立速溶龙眼粉的加工技术,运用均匀设计法优化了龙眼干中可溶性固形物酶解提取工艺条件,采用响应面分析法优化了其提取液的喷雾干燥工艺条件,结果表明：以龙眼果肉干（含水率13.62 %）为原料,用果胶酶和纤维素酶同时酶解提取,pH3.1,酶解温度52℃,酶解时间160 min,果胶酶用量0.6‰,纤维素酶用量0.15‰,龙眼干中可溶性固形物得率达85.26%;当酶解提取液中可溶性固形物浓度达25%时,采用喷雾干燥法,选取麦芽糊精为助干剂,其与可溶性固形物含量比0.8：1,热风温度185℃,热风流量26.47 m3/h,入料流量0.20 L/h,在此条件下,龙眼粉得率为48.58%,含水率＜5%,水溶性良好,色泽风味佳。由此说明,以龙眼果肉干为原料采取酶解提取与喷雾干燥相结合的工艺可有效加工速溶龙眼粉。 相似文献
10.
《南方农业》2020,(1)
为优化茶叶可溶性膳食纤维(Tea soluble dietary fiber,TSDF)的超声波辅助酶法提取工艺,以福鼎大白茶一芽五叶、六叶鲜叶为原料,采用单因素试验和正交试验研究纤维素酶用量、超声时间、超声功率、酶解温度对TSDF提取率的影响,分析TSDF组分含量和理化特性。结果表明:各因素对TSDF提取率影响的顺序依次为酶解温度超声功率纤维素酶用量超声时间;提取TSDF最优工艺为纤维素酶用量0.8 g·(100 g)~(-1)、超声时间30 min、超声功率300 W、酶解温度60 ℃,提取率为45.50%;TSDF组分包括果胶(85.82%)、水分(4.57%)、灰分(2.55%)、蛋白质(2.44%)、半纤维素(1.26%)、茶多酚(1.10%),具有良好的膨胀力、持水力等理化特性。 相似文献
11.
12.
Brown rice kernels (japonica type) were soaked in water at different temperatures (25 or 50°C) before cooking to a moisture content of 20 or 30%. Soaked brown rice was cooked in either the soaking water (SW) or in distilled water (DW) (rice solids to water ratio 1:1.4). Color, texture, and in vitro digestive properties of the cooked rice were examined. When the soaking temperature was higher (50°C vs. 25°C), water absorption and starch leaching were greater. To reach 20% moisture, the rice required 1 hr of soaking at 50°C but 2 hr of soaking at 25°C. Both the moisture content of the soaked rice and the soaking temperature affected the texture of the cooked brown rice. Rice that attained 20% moisture content during soaking was harder and less adhesive when cooked compared with rice that attained 30% moisture content. The rice soaked at 50°C was slightly softer but more adhesive when cooked than rice soaked at 25°C. The soaking temperature and moisture content of the rice kernels also affected the digestive properties of the cooked rice. The cooked brown rice that had attained 30% moisture before cooking was digested to a greater extent than rice that had attained 20% moisture. Even at equal moisture content, the rice soaked at the higher temperature (50°C) was digested more readily. It was assumed that the amount of soluble material leached during soaking differed according to the soaking temperature and moisture content, which subsequently affected the texture and digestive properties of the cooked brown rice. The rice cooked in its own soaking water was harder and more adhesive, had higher levels of resistant starch (RS), and exhibited smaller glycemic index (GI) values than its counterpart cooked with distilled water. This result indicated that the soluble material leached during soaking made the cooked rice harder and less digestible, perhaps due to interactions between these molecules and the gelatinized rice during cooking. 相似文献
13.
Ashley Han Emily O. Arijaje Jia‐Rong Jinn Andy Mauromoustakos Ya‐Jane Wang 《Cereal Chemistry》2016,93(1):39-46
Germinated brown rice is popular in Asia for its increased γ‐aminobutyric acid (GABA) content and sweeter and softer texture compared with conventional brown rice. However, most studies investigated germinated rice properties on medium‐grain or aromatic rice. The objective of this study was to compare differences between a medium‐grain (Jupiter) and a long‐grain (Wells) rice under similar germination conditions on their milling, physicochemical, and textural properties over the course of germination. Rough rice was soaked in water at 25°C for 12 h and then incubated at 30–34°C for four germination durations. Wells had a higher breakage percentage and a greater weight decrease than Jupiter during germination. Wells had a significantly lower GABA content before germination and at the first two germination durations than Jupiter, but the GABA content in Wells significantly increased at the third germination duration to become significantly higher than that of Jupiter. There were no significant changes in gelatinization temperatures and pasting properties of germinated rice from both cultivars at different germination durations. The cooked rice hardness from Wells decreased at the longest germination duration, whereas Jupiter showed a more significant decrease in cooked rice stickiness from germination. The results demonstrate that the impacts of germination on physical, chemical, and textural properties of rice were affected by grain type and germination duration. 相似文献
14.
Lamberts L Brijs K Mohamed R Verhelst N Delcour JA 《Journal of agricultural and food chemistry》2006,54(26):9924-9929
Rice color changes from white to amber during parboiling (soaking and steaming). Color parameters indicated that, during soaking, yellow bran pigments leached out in the water. The levels of the Maillard precursors (i.e., reducing sugars (RS) and free alpha-amino nitrogen (FAN)) depended on soaking temperature and time: leaching of RS was compensated by enzymic formation for long soaking times (>60 min), while proteolytic activity was too low to compensate for FAN leaching. Rice soaking under nitrogen, oxygen, or ambient conditions and determination of polyphenol oxidase activity allowed us to conclude that the effect of enzymic color changes on the soaked rice color was rather small. Color measurements of brown and milled mildly, intermediately, and severely parboiled rice samples showed that both brown and milled rice samples were darker and more red and yellow after parboiling and that the effect depended on the severity of parboiling conditions. Furthermore, steaming affected the rice color more and in a way opposite to that observed in soaking. The changes in RS and the loss of FAN during parboiling suggested that Maillard type reactions occur during brown rice steaming. Analyses of furosine levels confirmed Maillard browning of outer bran layers and endosperm during steaming. The level of this Maillard indicator increased with the severity of parboiling conditions in both brown and milled parboiled rice. Measurements of the levels of bran pigments indicated that bran pigments diffuse into the endosperm during parboiling and contribute to the parboiled rice color. 相似文献
15.
L. Lamberts E. De Bie V. Derycke W. S. Veraverbeke W. De Man J. A. Delcour 《Cereal Chemistry》2006,83(1):80-85
The effects of the soaking and steaming steps in rice parboiling on color changes and the levels of reducing sugars in rice were studied. Brown rice was soaked to different moisture contents (MC, 15, 20, 25, and 30%). The L*, a*, b* color parameters of the Commission Internationale de L'Eclairage (CIE 1976) indicated that during soaking, red and yellow bran pigments diffused from the bran into the endosperm. The increase in brightness brought about by soaking rice was attributed to migration of rice compounds (e.g., lipids) from the inner to the outer bran layers (rice surface). The levels of reducing sugars in brown and milled soaked rice samples increased with increasing brown rice MC after soaking. The total color difference (ΔE) between parboiled and nonparboiled rice increased with increasing MC after soaking and depended on the intensity of the steaming conditions as reflected in the degree of starch gelatinization. Parboiling affected yellowness more than redness in mildly steamed brown rice and most in intermediately steamed brown rice. Severe steaming of brown rice affected redness more than yellowness. All three parboiling conditions equally affected the yellow color more than the red color in milled rice. Linear regression analyses indicated that parboiling had a larger effect on ΔE of milled parboiled rice than of brown parboiled rice. Furthermore, the linear relationship between the level of gelatinized starch and ΔE of the milled parboiled rice samples showed that both parameters are indicators for the degree of parboiling. Reducing sugars were formed and lost during steaming, suggesting Maillard reactions during steaming. 相似文献
16.
Germinated brown rice is considered a more nutritious and palatable cooked product than conventional brown rice. However, germination usually decreases rice milling yield and alters some physicochemical properties. Parboiling is commonly used to increase milling yield and retain nutrients, but it also changes rice color and texture. The objective of this study was to investigate the effect of parboiling on milling, physicochemical, and textural properties of a medium‐grain and a long‐grain rice after germination at varying durations. Germinated rice samples of three germination durations were prepared with one germination time before the optimum time at which 70% of rice revealed hull protrusion, the optimum time, and one time after. Germinated rice was then immediately parboiled at 120°C for 20 min and was then immediately dried. The milling, physicochemical, and textural properties of parboiled germinated rice from both cultivars were determined. Parboiling significantly decreased the percentage of brokens, whiteness, and the apparent amylose content and increased γ‐aminobutyric acid content (GABA) in the nongerminated rice and rice at the first germination duration for both cultivars. Parboiling reduced pasting viscosities for both cultivars, but Jupiter still exhibited higher pasting viscosities than Wells. Cooked parboiled germinated rice was overall softer than nonparboiled rice because of kernel splitting, but Wells remained harder and less sticky than Jupiter. In conclusion, it is beneficial to combine parboiling with germination to enhance nutritional values and improve milling properties without affecting textural properties for both rice cultivars. 相似文献
17.
If properly executed, parboiling, a hydrothermal treatment consisting of soaking, steaming, and drying of rice, substantially reduces its milling breakage susceptibility. Here, brown rice was soaked at 40, 55, or 65°C for different times (150 s to 240 min) and subsequently parboiled under standardized steaming and drying conditions. The moisture absorption during initial soaking induced fissures in more than 90% of the rice grains, which disappeared with further soaking. The fissuring incidence in the soaked rice samples was related to that of the parboiled rice samples. The extent of starch gelatinization during steaming increased with the moisture content of the soaked grains. In addition, as a result of starch gelatinization, the level of white bellies (i.e., parboiled grains with translucent outer layers and an opaque center) decreased from over 90% to less than 3%. Rice grains need to absorb sufficient moisture during soaking to minimize the level of breakage‐susceptible white bellies and fissured rice grains in the parboiled end product. 相似文献
18.
Chalkiness is one of the most influential factors on head rice yield. Parboiling is known to be an effective way to remove chalkiness and improve head rice yield. However, the steps involved in the removal of chalkiness are still not completely resolved. This study investigated the effects of soaking temperature, soaking duration, and drying conditions on the removal of rice chalkiness. Chalky brown rice kernels were selected and soaked at 25, 65, 70, or 75°C for 3 h. After 1, 2, or 3 h, the rice samples were frozen before drying or immediately dried. Soaking at 25°C did not remove chalkiness and caused no morphological change in starch granules. When the soaking temperature increased from 25 to 65, 70, and 75°C, the chalkiness decreased from 100% to 34.1, 29.7, and 15.9%, respectively. Soaking rice at temperatures above the starch glass transition temperature but below the gelatinization temperature reduced chalkiness owing to rearrangement of starch granules and protein denaturation to fill the void spaces in the chalky area. During soaking, the morphology of starch granules also changed from round to angular in shape. Drying at temperatures above the starch glass transition temperature also facilitated rearrangement of starch granules to further reduce rice chalkiness. 相似文献
19.
《Cereal Chemistry》2017,94(5):798-800
Internal stresses owing to moisture and temperature gradients often result in the development of rice kernel fissures. Fissured rough rice kernels tend to break upon milling and potentially reduce the market value of rice. This work was conducted on the premise that fissures may be healed by soaking in water at a specific temperature and duration. Fissured rough rice kernels of a long‐grain cultivar, Wells, were selected by X‐ray imaging. Fissured kernels were soaked in a water bath at six soaking temperatures (22, 60, 65, 70, 75, and 80°C) and three soaking durations (1, 2, and 3 h) and then gently dried for characterization. X‐ray images revealed that soaking at 75°C for 3 h healed up to 70.0% of the fissured kernels. Soaking at 22, 60, or 65°C did not result in healing. For normal kernels, soaking at different temperatures for 3 h created fissures. Bending tests using a texture analyzer showed that brown rice breaking force increased from 18.5 N (fissured kernels) to 43.7 N (healed kernels). Soaking rough rice in water at a temperature slightly above its onset gelatinization temperature may potentially heal fissures. 相似文献