调质大米半干法磨粉制备鲜米粉及其品质测定

为考察半干法磨粉对鲜米粉品质的影响,该研究选用旋风磨和布勒磨对调质后含水率为28%和30%的大米进行磨粉,分析大米粉的白度、凝胶特性及糊化特性,对加工鲜米粉的质构特性、蒸煮特性和感官品质进行了分析。结果显示:调质大米可以减小磨粉仪器机械力和热能对大米粉品质的破坏,其中调质大米经布勒磨粉碎后的白度显著高于湿磨粉白度(P0.05);旋风磨含水率为30%调质粉的凝胶硬度最大为3.45 N/cm2,与湿磨粉的无显著差异(P0.05);2种调质粉相比于湿磨粉其崩解值较小,其中布勒磨含水率为30%调质粉回生程度较低,与湿磨粉无显著差异(P0.05)。对于鲜米粉的品质,筛选得到的旋风磨含水率为30%鲜米粉的硬度为35.10 N/cm2,弹性为0.97,较湿磨米粉更柔软弹滑,感官评价总分和蒸煮特性与湿磨米粉无显著差异。以上结果表明,含水率为30%的大米经旋风磨粉碎后能够制得与湿法磨浆相媲美的鲜米粉,可为解决湿磨法废水量大、产品得率低等问题提供参考。     

欧姆加热对米饭蒸煮过程能耗及其品质的影响

电饭煲蒸煮米饭存在电热转化效率低、温度不易控制等不足。该研究设计了一种加热速率和保温温度自动可控的欧姆加热试验系统，并研究了浸泡时间和水米比对水米混合物的电导率、欧姆蒸煮加热速率、能耗以及米饭品质（膨胀率、吸水率、物性值和颜色）的影响，并与电饭煲蒸煮米饭的能耗和品质进行比较。结果表明：浸泡能够增大水米混合物电导率，水米比越小电导率增加越快，有效提高欧姆加热蒸煮米饭加热速率；浸泡还有利于减少米饭蒸煮能耗（P<0.05），促进米饭软化；因此大米浸泡处理30 min后采用欧姆加热蒸煮米饭可行。欧姆蒸煮加热速率越快，米饭硬度上升（P<0.05），而黏性和弹性则略有减小（P<0.05），加热速率在3～9 ℃/min范围内为宜；水米比可取1.25∶1～1.50∶1 mL/g。蒸煮相同质量的大米，欧姆加热所需能耗仅为电饭煲蒸煮的20%～25%；相较于电饭煲蒸煮，欧姆加热蒸煮米饭硬度最大可减小21%，且膨胀率和吸水率较大（P<0.05）、亮度L*值较小（P<0.05）。研究结果可为研发基于欧姆加热的快速高效米饭自动蒸煮装置提供技术支撑。     

豌豆粉添加对米粉品质特性的影响

为了提高米粉的营养价值,本研究将不同粒径的豌豆粉添加到米粉中,分析不同粒径及添加量(0%、7.5%、15%、30%)对大米粉粉质特性及米粉蒸煮、质构和感官特性的影响。结果表明,添加豌豆粉可以增加米粉中蛋白质的含量,添加30%豌豆粉后米粉的蛋白质含量为原米粉的1.73倍。豌豆粉的添加降低了米粉的峰值黏度、最终黏度和回生值,提高了米粉冷糊稳定性,使米粉不易老化。随着豌豆粉添加量的增加,米粉的硬度与蒸煮损失逐渐增大,感官品质降低。豌豆粉的粒度对米粉品质影响较大,当豌豆粉添加量相同时,添加200目豌豆粉的米粉蒸煮损失比添加80目豌豆粉降低9.08%~20.73%;感官评价总分提高1.35%~10.43%。综上,通过降低豌豆粉的粒度可以制备出豌豆粉添加量为30%的品质较好的米粉。本研究结果为营养健康型米粉的开发提供了一定的理论基础。     

不同冻藏温度条件下速冻汤圆品质变化及其机制

为探究不同恒温冻藏条件下速冻汤圆品质的变化规律,将速冻汤圆置于-5、-15、-25℃ 3种恒定冻藏条件下,定期测量含水率、酸价、过氧化值、质构等品质指标,并结合核磁共振成像、快速黏度分析仪、扫描电子显微镜测定粉团水分迁移、糊化特性、微观结构等,揭示冻藏温度对其品质变化的影响。结果表明：冻藏温度对速冻汤圆的含水率、过氧化值、酸价、质构等均有显著性影响（P<0.05）,冻藏时间越长,冻藏温度越高,速冻汤圆含水率下降越多,过氧化值、酸价、硬度、咀嚼性增加也越大,其中在第40天,-5℃与-15、-25℃冻藏条件相比,速冻汤圆含水率率先下降至平稳点,过氧化值、酸价增长率（14%和20%）远高于其它2组,第90天,-5℃冻藏条件下速冻汤圆含水率减少11.32%,过氧化值、酸价分别上涨23%和30%,硬度、咀嚼性由392.11、66.24 g增大到511.78、90.11g,且与-25℃冻藏条件相比有显著性差异（P<0.05）。核磁共振、糊化特性、扫面电镜显示：较高温度冻藏条件下速冻汤圆水分自由度增长较大,冰晶的生长及大冰晶的形成使得淀粉颗粒受到机械损伤,破损淀粉填充糯米粉团空隙,致密的组织结构抑制蒸煮时水分进入以及热量的传递,使得速冻汤圆硬度、咀嚼性大幅上涨;破损淀粉易吸水膨胀,占有较多的空间,致使峰值黏度、崩解值、最终黏度降低,从而影响速冻汤团品质特性。以上研究结果为速冻汤圆在冻藏期间的品质保持提供理论参考。     

冷冻贮藏环境对速冻水饺皮品质特性的影响

为了保证速冻水饺的冻藏品质,掌握冻藏环境对品质影响的规律,该试验以速冻水饺皮为目标,排除饺馅的干扰,重点研究了冻藏期间温度的波动,时间的推移以及包装方式等对其理化特性、质构特性、感官特性以及微观结构等的影响。结果表明:随着冻藏时间的延长,速冻水饺皮糊化度降低,水分、直链淀粉、醇溶蛋白以及麦谷蛋白含量均呈现下降趋势,面筋蛋白显微网络结构弱化,但质构、感官特性变化不显著。采用透气性、阻湿性较好的PE塑料薄膜包装可以较好的保持速冻水饺皮的品质。冻藏期间的温度波动显著降低速冻水饺皮的外观品质和食用品质。该研究为改善速冻食品的贮藏环境提供了理论依据。     

菊粉对低脂乳化肠质构及风味品质的影响

为探究菊粉对低脂乳化肠质构及风味品质的影响,本研究以猪后腿肉为原料制作低脂乳化肠,并在肠中添加不同量浓度(0%、1%、2%、3%、4%和5%)的菊粉,以高脂组为对照,研究其对乳化肠基本营养成分、色泽、蒸煮损失、质构特性、微观结构、风味及感官品质的影响。结果表明,随着低脂乳化肠中菊粉添加量的增加,乳化肠水分和蛋白质含量均先增加后显著下降;加入适量菊粉可以降低低脂乳化肠的蒸煮损失;菊粉的加入增加了乳化肠的硬度和咀嚼性,提高了凝聚力。扫描电镜结果表明,菊粉添加量为4%时乳化肠的微观结构孔洞最小且致密;风味及感官评价结果表明,菊粉添加量为5%时醛类和醇类等风味成分含量达到最高,菊粉添加量达到 3%及以上时与对照组相比感官评价总分无显著差异。综上,低脂乳化肠中加入菊粉有利于降低低脂乳化肠的蒸煮损失,改善低脂乳化肠的质构特性及风味和感官品质。本研究结果可为低脂肉制品的生产提供一定的理论依据。     

活性小麦面筋对燕麦全粉面条品质的影响

本文研究了活性小麦面筋对燕麦全粉与小麦粉混合面粉胶的浆液性质和质构特性的影响,以及对面条烹煮性质和质构的影响。结果表明,添加活性小麦面筋使得混合面粉的热粘度和凝胶强度降低,热糊液趋于稳定,混合面粉胶的质构更为松散,硬度、紧实度和弹性有不同程度的降低;可以降低燕麦面条的烹煮产率、烹煮损失和断条率,增加面条的拉伸强度、硬度和紧实度,降低粘附性和表面脆性,烹煮后面条表面形成糊化层且存在束状结构,显著改善面条的感官品质。     

不同贮藏温度下籼粳杂交大米陈化规律研究

为研究不同贮藏温度下籼粳杂交大米品质变化规律，探讨其陈化机制，本研究以甬优1540杂交大米为试验材料，包装好后分别置于15、25、35℃(湿度60%)的恒温恒湿箱中贮藏180 d，每30 d检测其外观、理化、蒸煮、糊化等品质指标，每90 d测定其挥发性成分。结果表明，随着贮藏时间的延长，甬优1540籼粳杂交大米的明度值(L^*)、脂肪含量、脂肪酶活力、蛋白质含量、巯基含量、过氧化氢酶活力、米饭弹性、米饭黏着性、米汤固形物含量逐渐下降，红绿偏差值(a^*)、蒸煮吸水率、膨胀率、米饭硬度、峰值黏度、崩解值、回生值、糊化温度等指标持续上升；除蓝黄偏差值(b^*)等少数指标外，各指标间相关性显著(P<0.01)。气相-离子迁移谱(GC-IMS)分析结果表明，甬优1540稻米的挥发性成分在贮藏过程中发生了较复杂的变化，在贮藏前90 d，醇酮类物质含量升高、醛类物质含量降低，90～180 d萜类物质含量明显升高；温度升高会加剧以上反应的进程。本研究为籼粳大米贮运生产提供了数据支持和理论依据。     

高压均质对油脂预乳化大豆拉丝蛋白素食香肠质构特性的影响

为了将预乳化工艺更好应用于大豆拉丝蛋白（Textured Fibril Soy Protein，TFSP）素食香肠的加工，该研究通过采用不同的蛋白乳化剂和调控均质条件，探究预乳化油脂对TFSP素食香肠流变特性、质构和微观结构的影响。结果发现随着均质压力从0增大到30 MPa，大豆分离蛋白（Soybean Protein Isolate，SPI）乳液和酪蛋白酸钠（Sodium Caseinate，SC）乳液的表观黏度都逐渐增大，SPI乳液粒径为24.80～0.39 μm，SC乳液粒径为12.37～0.12 μm。对TFSP素肉糜进行温度扫描和频率扫描结果发现，所有的素肉糜在蒸煮后都形成了具有黏弹性的乳液凝胶，并且预乳液的均质压力越大，素肉糜的弹性模量越大。沃-布剪切测试和质构特性（Texture Profile Analysis，TPA）测试发现，TFSP素食香肠的剪切力和TPA质构特性都随着预乳液均质压力的增大而增大。采用激光共聚焦显微镜观察分析了不同预乳液和TFSP素食香肠的微观结构，当预乳化的均质压力为0～20 MPa时，SC乳液制备的TFSP素食香肠在蒸煮后发生了明显的乳液滴聚结；然而SPI乳液制备的TFSP素食香肠在蒸煮后表现出对抗乳液滴聚结的能力强。因此，采用SPI对植物油脂进行预乳化过程中，均质压力为20 MPa时，可以有效提升TFSP素食香肠的切片性和质构特性，研究结果为油脂预乳化工艺在素食产品中的开发和应用提供参考。     

高压微射流均质对墨鱼汁生鲜面蒸煮及质构特性的影响

为提高墨鱼汁在食品加工业中的应用价值,将高压微射流均质处理后的墨鱼汁添加到生鲜面中,分析不同处理压力(0、40、80、120、160、200 MPa)对墨鱼汁粒径变化及墨鱼汁生鲜面蒸煮、质构特性的影响。结果表明,微射流最佳处理压力为120 MPa。该条件下,墨鱼汁粒径显著减小为101.20 nm(P<0.05),墨鱼汁生鲜面条最佳蒸煮时间为315 s,蒸煮断条率和蒸煮损失率分别降低至4.44%和4.98%,膨胀率增加至183.50%,硬度、咀嚼性分别达到642.37 g、176.84 g,感官评价综合得分为94.31。扫描电镜结果显示,微射流处理后墨鱼汁生鲜面结构变得更加均匀致密,孔隙相对减小,结构得到改善。综上,微射流可较好地改善墨鱼汁生鲜面的蒸煮特性和质构特性。本研究结果为墨鱼汁食品的开发提供了一定的理论依据。     

Soaking Conditions During Brown Rice Parboiling Impact the Level of Breakage‐Susceptible Rice Kernels

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.     

Quantitative and Qualitative Role of Added Gluten on White Salted Noodles

A commercial gluten and glutens isolated from four soft and four hard wheat flours were incorporated into a hard and a soft white flour by replacement to directly determine the quantitative and qualitative role of gluten proteins in making noodles. Gluten incorporation (6%) decreased water absorption of noodle dough by 3%, shortened the length of the dough sheet by 15 and 18%, and increased the thickness of the dough sheet by 18 and 20% in soft and hard wheat flour, respectively. Noodles imbibed less water and imbibed water more slowly during cooking with gluten incorporation, which resulted in a 3‐min increase in cooking time for both soft and hard wheat noodles. Despite the extended cooking time of 3 min, noodles incorporated with 6% gluten exhibited decreases in cooking loss by 15% in soft wheat. In hard wheat flour, cooking loss of noodles was lowest with 2% incorporation of gluten. Tensile strength of fresh and cooked noodles, as well as hardness of cooked noodles, increased linearly with increase in gluten incorporation, regardless of cooking time and storage time after cooking. While hardness of cooked noodles either increased or showed no changes during storage for 4 hr, tensile strength of noodles decreased. There were large variations in hardness and tensile strength of cooked noodles incorporated with glutens isolated from eight different flours. Noodles incorporated with soft wheat glutens exhibited greater hardness and tensile strength than noodles with hard wheat glutens. Tensile strength of cooked noodles incorporated with eight different glutens negatively correlated with SDS sedimentation volume of wheat flours from which the glutens were isolated.     

Effect of Processing Conditions on Color Change of Brown and Milled Parboiled Rice

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.     

Impact of Starch Gelatinization and Kernel Fissuring on the Milling Breakage Susceptibility of Parboiled Brown Rice

Parboiling, a hydrothermal treatment of paddy or brown rice, improves the texture and nutritional characteristics of cooked rice. We investigated milling breakage susceptibility of brown rice parboiled under different soaking and steaming conditions, resulting in samples with different degrees of starch gelatinization and levels of fissured grains and white bellies, that is, parboiled grains with translucent outer layers and an undesirable opaque center. The milling breakage susceptibility was 2.1% for raw rice and ranged from less than 1% up to 11.3% for parboiled rice. Parboiled samples with increased milling breakage susceptibility contained higher levels of white bellies and fissured grains. In white bellies, starch gelatinization is incomplete. Scanning electron microscopy revealed inhomogeneities in individual white bellies and fissured rice grains, indicating moisture gradients inside the grains during parboiling. Starch needs to be completely gelatinized to ensure the absence of white bellies and minimal fissured grain levels in the parboiled end product and, as a consequence, a decreased milling breakage.     

Physicochemical Changes in Nontraditional Pasta During Cooking

Physicochemical changes in the components of nontraditional spaghetti during cooking were reflected in the quality of the cooked product. Spaghetti formulations used were semolina (100%), whole wheat flour (100%), semolina/whole wheat flour (49:51), semolina/flaxseed flour (90:10), whole wheat flour/flaxseed flour (90:10), and semolina/whole wheat flour/flaxseed flour (39:51:10). Spaghetti quality was determined as cooking loss, cooked weight, and cooked firmness. Physicochemical analyses included total starch, starch damage, pasting properties, and protein quality and quantity of the flour mixes and spaghetti cooked for 0, 2, 4, 10, and 18 min. As cooking time progressed, total starch content decreased up to 5.7% units, starch damage increased up to 11.7% units, and both pasting parameters and protein solubility decreased significantly in all six formulations. Changes in the starch damage level, total starch content, and pasting properties of spaghetti correlated significantly (P < 0.05) with the cooking loss, cooked weight, and cooked firmness values recorded for the spaghetti. High levels of glutenin polymers and low levels of the albumin and globulin fractions were associated with low cooking losses and cooked weight and with high cooked firmness, indicating the involvement of these proteins in the cooked quality of nontraditional spaghetti.     

Impact of browning reactions and bran pigments on color of parboiled rice

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.     

Changes in glucosinolate concentrations, myrosinase activity, and production of metabolites of glucosinolates in cabbage (Brassica oleracea Var. capitata) cooked for different durations

In cabbage, glucosinolates such as sinigrin are hydrolyzed by plant myrosinase to allyl isothiocyanate (AITC), allyl cyanide, and, in the presence of an epithiospecifier protein, 1-cyano-2,3-epithiopropane (CEP). Isothiocyanates have been implicated in the cancer-protective effects of Brassica vegetables. The effect of processing on the hydrolysis of glucosinolates was investigated in cabbage. Cabbage was steamed or microwaved for six time durations over 7 min. Glucosinolate concentrations were slightly reduced after microwave cooking (P < 0.001) but were not influenced after steaming (P < 0.05). Myrosinase activity was effectively lost after 2 min of microwave cooking and after 7 min of steaming. Hydrolysis of residual glucosinolates following cooking yielded predominantly CEP at short cooking durations and AITC at longer durations until myrosinase activity was lost. Lightly cooked cabbage produced the highest yield of AITC on hydrolysis in vitro, suggesting that cooking Brassica vegetables for a relatively short duration may be desirable from a health perspective.     

Effect of Variable Parboiling on Crystallinity of Rice Samples

Rice parboiled at various combinations of soaking temperature and steaming time were analyzed by differential scanning calorimetry (DSC) and X‐ray diffraction (XRD). Generally, gelatinization enthalpy decreased as the soaking temperature increased from 30°C to 50°C and 70°C to 90°C, and gelatinization enthalpy decreased as steaming times increased from 4 and 8 min to 12 min. As expected, a distinctive A‐pattern was observed in the XRD of raw rice. The most severely parboiled laboratory sample (90°C for 12 min), showed no discernable change toward the V‐pattern. Crystallinity decreased from the raw rice (24.6%) with increased cooking temperature.     

Effect of Presoaking on Textural,Thermal, and Digestive Properties of Cooked Brown Rice

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.     

Effects of Processing Conditions and Sorghum Cultivar on Alkaline-Processed Snacks

Sorghum (Sorghum bicolor (L.) Moench) grain was boiled or autoclaved in alkali, washed, drained, and dried into shelf-stable half-products (pellets). The pellets were deep-fat fried to produce a crunchy snack product. Effects of cooking time, drying method (pellet moisture content), and sorghum cultivar on unfried and fried pellets were evaluated. Increasing the alkaline cooking time from 30 to 60 min decreased the yield of the pellets from 96 to 84% (on a dry weight basis). Cooked sorghum dried at room temperature (24°C) for 18 hr, followed by oven-drying at 50°C for an additional 18 hr, produced pellets with a low moisture content (≤5%), that required a higher frying temperature (≥220°C). However, cooked sorghum dried at room temperature for 18 hr followed by oven-drying at 50°C for 5 hr produced pellets with 9% moisture and a lighterdensity highly acceptable product when fried at 220°C. Fat content of fried pellets averaged 18%. The optimum method for producing a light, crunchy, fried product was cooking for 60 min, drying to 9% moisture, and frying at 220°C. ATx631*Tx436, the hardest endosperm-texture sorghum used in the study, had the highest unfried and fried pellet yields. Dorado, an intermediate-to-soft endosperm-texture sorghum, and ATx Arg-1*Tx2907, a waxy sorghum, had lower yields. The fried pellets produced from Dorado and waxy sorghum (ATxArg-1*Tx2907) were more expanded than those produced from ATx631*Tx436.