干燥工艺对紫薯全粉理化性质及花色苷的影响

为了提高紫薯全粉的品质,保留其营养价值,本文以紫薯\     

Influence of Cooking Method on Digestibility of Legume and Cereal Starches

The influence of processing on starch nutrition was evaluated. Cereal starches including wheat, normal corn and high amylose corn; legume starches including field pea, kidney bean and mung bean; and potato starch and glucose were evaluated as carbohydrate sources. Starches were fed raw, or cooked in a pressure kettle or autoclave, dried in a spray drier or freeze-drier, or simultaneously cooked and dried on a drum drier or by extrusion cooking. Except for potato and high amylose corn, cooking the starches provided no nutritional advantage, as evaluated by weight gain, feed efficiency ratio, or apparent protein digestibility. Spray-dried starches were less dense and appeared to influence growth by restricting food consumption.     

预制条件及干燥方式对自热米饭品质的影响

本实验针对目前自热米饭蒸煮品质差的问题,研究了预制条件及干燥方式对自热米饭品质特性的影响。结果表明,预处理过程中,随着加水倍数的增加,预制米饭的硬度从23373.68 g降低到1932.88 g,胶着度从17077.79减小到715.41,咀嚼度从14374.99减小到393.99,回复性从0.53减小到0.12;随着蒸煮时间的增加,预制米饭的硬度从26595.48 g降低到18696.83 g,并随后呈现上升趋势,咀嚼性从13952.22降低到10642.24。冷冻干燥和鼓风干燥方式下,加水倍数1.3,蒸煮时间40 min制备的预制米的糊化度达到最大值;微波干燥下,加水倍数0.6,蒸煮时间20 min制备的预制米的糊化度达到最大值。通过扫描电镜观察到冷冻干燥得到的预制米断面多孔粗糙,且制备的自热米饭复水后的质构特性最佳;而通过电子鼻测得鼓风干燥制备的自热米饭的香味更为浓郁。     

Noodle quality affected by different cereal starches

To investigate the effects of starch characteristics on the quality of noodle making, white salted noodles (WSN) made from reconstituted flours, in which the wheat starch was substituted by different cereal starches, including waxy and non-waxy rice starches, waxy wheat starch and waxy corn starch, were prepared. The rheological properties of raw WSN were mainly influenced by the size of starch granules, where the small starch granules, such as for rice starches, exhibited high amounts of water absorption during dough preparation and a dense packing of starch granules inside a thin gluten-strand network. The rheological properties of cooked WSN were mainly dominated by the amylose content and fine structure of the amylopectin, which resulted in the differences in water absorption and cooking time required for cooked WSN.     

预糊化处理对高含量燕麦挂面品质的影响

为研究燕麦预糊化处理对高含量燕麦挂面品质的影响,本文采用蒸制、挤压膨化和滚筒干燥对燕麦进行预糊化处理,分析不同类型与添加量的预糊化燕麦粉对混合粉(燕麦粉总量为70%)糊化特性及挂面力学特性、蒸煮品质和煮后面条质构特性的影响。结果表明,随着预糊化粉添加量升高,混合粉的室温粘度增大;混合粉的热粘度与蒸制燕麦粉(SOF)添加量成正相关,与挤压预糊化粉(EOF)和滚筒预糊化粉(DOF)添加量成负相关。SOF添加量为70%时,燕麦挂面品质最好;而EOF和DOF添加量为8.75%时,挂面品质最好。相比之下,前者的弹性模量、断裂应力、断裂位移、咀嚼性更大,黏附性、蒸煮损失率更小。综上,添加预糊化粉可以改善挂面品质,采用SOF制备的燕麦挂面品质最佳。     

Effect of Processing on the Physico-Chemical Characteristics of Quinoa Flour (Chenopodium quinoa,Willd)

The nature and extent of the modification of starch in quinoa, caused by various processes like cooking and autoclaving of the seeds, drum drying of the flour and extrusion of the grits was investigated by measuring the physico-chemical properties - the water absorption, water solubility, swelling power, viscosity and degree of gelatinisation - of the processed samples. Autoclaved samples showed the lowest degree of gelatinisation (32.5% by DSC) of the starch, while the degree of gelatinisation of the precooked/drum dried samples was found to be 97.4% by DSC method. Higher polymer degradation was observed in cooked samples than in autoclaved samples as seen in the gel chromatographic separation. The water solubility in cooked samples (5.44 to 15.58) and in autoclaved samples (7.02 to 9.64) increased with the process time. In the extrusion process, the moisture content as well as the compression ratio was found to affect the degree of starch modification significantly (p <0.01).     

Changes in characteristics of sweet potato flour prepared by different drying techniques

The changes occurring in the characteristics of sweet potato flour as a result of processing were investigated. Pasting behaviour of drum dried and hot air-dried sweet potato flour was determined using Rapid Visco-Analyser. The pasting characteristics decreased due to gelatinization of starch during processing. The degradation of starch by amylases during hot air drying further lowered the water binding capacity/viscosity and total amylose and increased the digestibility compared to those of drum dried and native flour. Swelling power and solubility of the flours increased as a result of processing which subsequently increased with increase in temperature. Scanning electron micrographs of starch granules showed tendency of clustering, especially in drum dried samples. X-ray diffraction patterns showed alteration from Ca-type to V-type with a marked reduction in crystallinity index as a result of processing. The ¹³C NMR spectra of processed starches showed reduced peak intensities and line widths due to depolymerizing effects, and also pointing to their change in crystallinity.     

三种马铃薯氧化淀粉的部分性质及其对哈尔滨红肠品质的影响

采用过氧化氢、次氯酸钠和二氧化氯作为氧化剂制备马铃薯氧化淀粉,然后对其部分性质进行研究,并考察了其对哈红肠品质的影响.其中,H2O2作为氧化剂制备的氧化淀粉,其羰基含量明显高于次氯酸钠氧化淀粉和ClO2氧化淀粉.与原淀粉比较,三种氧化淀粉的凝沉性有了不同程度的提高,其透光率也显著提高.马铃薯原淀粉经ClO2氧化后,粘度提高至原淀粉粘度的3倍,而H2O2和次氯酸钠制备的氧化淀粉,其粘度则显著降低.由电镜扫描结果可知,马铃薯原淀粉经H2O2、次氯酸钠和ClO2氧化后,淀粉表面变得较为粗糙.将三种马铃薯氧化淀粉添加到哈尔滨红肠中,通过质构分析发现红肠的硬度和咀嚼性显著提高,而弹性和内聚性无明显差异.     

Effects of Applied Process on the In Vitro Digestibility and Resistant Starch Content of Pasta Products

Resistant starch (RS) included in pasta can have auspicious health benefits and functional properties. The resistance of starch, however, can be greatly influenced by the applied food preparation process. The aim of the present study was to investigate the effects of two different resistant starches on the digestibility of pasta and to predict the impact of the conventional pasta processing (extrusion under standard conditions, 120 bars, 40°C; drying in an air-drying room at 35–40°C and cooking until the optimum cooking time) on the quality of different resistant starch included in products by using an in vitro enzymatic hydrolysis method. Results showed that the applied, conventional pasta extrusion step had only a small effect on the liberated glucose level and did not influence the RS content significantly. The cooking in contrast caused an increased digestibility and the lost of resistance of all pasta products. The digestibility was significantly lower (p < 0.05) in the case of raw and dried samples compared to the cooked pastas. It can be concluded that the resistant starches used in the samples are heat sensitive and their properties change radically during the pasta preparation, mainly during cooking.     

Rheological and textural studies of fresh and freeze-thawed native sago starch–sugar gels. II. Comparisons with other starch sources and reheating effects

The viscoelastic and textural properties of freshly prepared and freeze-thawed sago starch–sugar gels were studied in comparison with other native starches from corn, wheat, tapioca, and potato. The gelatinisation and retrogradation properties of starches were studied using a DSC while the pasting properties of starch–sugar mixtures during the cooking period were studied using a starch pasting cell. The freeze-thaw stability of gels was evaluated by gravimetric measurements of the water of syneresis. The different starches gave properties which varied following to their botanical sources. High-amylose cereal starches (wheat and corn) produced harder gels, while low-amylose root starch (tapioca) produced softer gels. Sago and potato gels showed close similarities in their viscoelastic and textural characteristics. Although the freeze-thaw cycle greatly increased the viscoelasticity and hardness of these two gels, reheating at high temperature significantly reduced these negative effects and resulted in partial recovery of the gel structures. Sago starch produced gels with very low syneresis and high cohesiveness, implying its potential use as a gelling agent in the frozen food industries.     

Effects of different crop starches on the cooking quality of Chinese dried noodles

To investigate the effects of seven starches made from different crop sources on noodle quality, Chinese dried noodles made from various reconstituted flours were prepared and analysed. Potato starch had better solubility and swelling power than the other starches, leading to higher water absorption, cooking loss and breakage ratio of the potato starch noodles. The correlation results unravelled that the cooking breakage ratio of noodles presented positive correlations with solubility, swelling power, peak viscosity (PV), trough viscosity (TV) and final viscosity (FV) values of starches. Besides, the adhesiveness of noodles showed a positive correlation with conclusion temperature (T_c) and setback viscosity (SV) values of starches. Moreover, the peak temperature (T_p) value of starches was negatively correlated with cooking loss; the granule size of starches had a positive correlation with noodles water absorption; and the peak time (PkT) value of starches represented positive relationships with noodles chewiness, shearing force and breaking strength.     

Influence of isolated flaxseed mucilage as a non‐starch polysaccharide on noodle quality

Physicochemical, cooking quality and sensory characteristics of noodles enriched by extracted flaxseed mucilage were evaluated. Noodles were prepared with replacement wheat flour with different mucilage concentrations and drying at different temperatures. Generally, physicochemical and noodle quality characteristics improved with adding flaxseed mucilage compared to control sample. The correlation between optimum cooking time with mucilage concentrations and drying temperatures established by nonlinear regression. The obtained data of cooking yield, swelling index, cooking loss and nitrogen loss were analysed using the two‐dimension response surface method. The mucilage concentration of 3% and drying temperature ranging between 68.2 and 70 °C were the best condition to prepare the noodle with high cooking quality compared to the control sample. The received scores from sensory evaluation showed that replacement of wheat flour by flaxseed mucilage improved the texture and overall acceptability of prepared noodle.     

不同干燥方式联合熟化处理对板栗粉品质特性及微观结构的影响

以新鲜板栗及经熟化处理的板栗为原料,采用热风干燥（hot air drying,HAD）、真空冷冻干燥（vacuum freeze drying,VFD）、真空射频干燥（radio frequency-vacuum drying,RFVD）和气体射流冲击干燥（air-impingement jet drying,AJID）4 种干燥方式分别加工制备板栗生、熟粉,探究熟化处理及不同干燥方式对板栗粉品质特性及微观结构的影响。结果表明,HAD制备的板栗生、熟粉的脂肪含量较高,但色泽和品质较差,且颗粒分布不均;VFD制备的板栗生、熟粉水分质量分数最低（3.01%、4.29%）、耐贮藏,其淀粉和游离酚含量均最高,粉体亮度最大且色泽较白,生粉颗粒呈不规则大片层状结构。RFVD和AJID制备的板栗生、熟粉还原糖含量均较高,游离酚含量显著高于HAD产物,微观结构保持度较好,但粉体色泽不佳。经熟化处理后,不同干燥方式制备的板栗熟粉持水性增加,堆积密度升高,但游离酚含量、亮度L*值降低,粉体颗粒体积膨胀,表面较粗糙,出现折叠起皱现象。综上,熟化和不同干燥方式处理对板栗粉的品质特性和微观结构均存在显著影响,因此要综合考虑生产成本和工业化生产需求来选择制备板栗粉的最佳方法。     

不同干燥方式对银杏全粉品质的影响

以银杏为原料,采用热风干燥、真空冷冻干燥、微波干燥、喷雾干燥和滚筒干燥等五种不同的干燥方法制备银杏全粉。研究5种干燥方式对银杏全粉银杏酸脱除率、营养活性成分、色差、持水性和持油性及糊化特性等指标的影响。结果表明:滚筒干燥对银杏酸脱除效果最显著,脱除率高达78.61%,大大提高产品的安全性,而其他干燥方式对银杏酸的脱除率均低于40%。喷雾干燥和真空冷冻干燥对活性成分的保留较好,黄酮和内酯的保留率分别达到86%和90%,而滚筒干燥相对较差;喷雾干燥和真空冷冻干燥生产的银杏全粉总色差ΔE较小(约20.43),而滚筒干燥生产的银杏全粉溶解度、吸水指数、吸油指数较大,分别为12.80%、8.23 g/g、2.95 g/g。为了确保银杏全粉的安全性,同时考虑生产成本及工业化生产的可行性,制备银杏全粉的干燥方式以滚筒干燥法为最佳。      

增强、助留剂YZ-138在造纸中的应用

木薯高取代阳离子淀粉YZ-138是针对以二次纤维为原料抄造牛皮箱板纸而开发的增强、助留剂。该文介绍了YZ-138的特性,并通过其在连续蒸煮方式和间歇蒸煮方式不同纸厂的应用实例表明,与普通阳离子淀粉和两性淀粉相比,YZ-138在留着及增强方面均要好得多。     

Physico‐functional and antioxidant properties of purple‐flesh sweet potato flours as affected by extrusion and drum‐drying treatments

Effects of extrusion and drum‐drying treatments on physico‐functional and antioxidant properties of flours prepared from purple‐flesh sweet potato were evaluated. Extrusion variables were feed moisture contents (MC; 10%, 13%, 16%) and screw speeds (SS; 250, 325, 400 r.p.m.), whereas drum‐drying was done at 120, 130 or 140 °C. Effects of MC were generally greater than SS on flour properties. Extruded flours showed higher water absorption and water solubility indices compared with control nonextruded flours. Regardless of SS, total phenolic content and antioxidant activities (DPPH and ABTS) of flours processed at 10% MC were significantly higher than those at 13% and 16%. Both extruded and drum‐dried flours exhibited no peak viscosity, indicating complete gelatinisation of starch. Maximum phenolic content and antioxidant activities of drum‐dried flours were obtained at 140 °C. Although drum‐dried flours had higher antioxidant capacity than extruded flours, both flours could potentially be used as food ingredients.     

Hypochlorite oxidation of field pea starch and its suitability for noodle making using an extrusion cooker

The effect of hypochlorite oxidation on the Brabendar pasting properties of field pea starch and the suitability of native and oxidized starch for noodle making by extrusion cooking were investigated. Field pea starch was oxidized with sodium hypochlorite at a level of active chlorine ranging from 0.89 to 3.28% (starch db). The degree of oxidation was determined and expressed in terms of percentage of carboxyl and carbonyl groups, which ranged from 0.02 to 0.38% and 0.06 to 0.19%, respectively. Starch recovery and peak viscosity, hot paste viscosity, cool paste viscosity, and setback of oxidized starches decreased with increasing degree of oxidation. The cooking quality attributes of noodles prepared from native field pea starches were acceptable but were negatively influenced by hypochlorite oxidation. Substitution of potato starch (40%, db) for field pea starch yielded more glossy noodles with better cooking quality. It was also observed that Brabendar pasting properties had high correlations with noodle quality characteristics.     

Starch/Sucrose Interactions by Organic Probe Analysis: An Inverse Gas Chromatography Study

The effect of freeze drying of high amylopectin starch was determined with samples of starch dispersed in water with or without solubilized sucrose. The X-ray diffraction data showed that this treatment disrupted crystalline structures of amylopectin and sucrose exposing additional sites for water sorption. This was shown also by sorption isotherms of the starch alone. The Hylon 7-sucrose freeze-dried samples produced a greater effect on sorption than did the corresponding Amioca freeze-dried mixtures. Organic probe analysis of the starch and starch-sucrose mixtures indicated that high amylose starches were more reactive with polar organic probes than high amylopectin starches when freeze-dried. Untreated high amylopectin starches were more reactive with probes in agreement with the water sorption data for a more branched polymer.     

Cross-linking of wheat starch improves the crispness of deep-fried battered food

Wheat starches with different degrees of cross-linking were used to study the effect of starch gelatinization in the batter and crust characteristics of deep-fried battered food. Pasting properties, viscosity and batter pick up as well as moisture and oil content and crispness of the fried crusts were evaluated. In batters prepared with a constant solids/water ratio, the cross-linked starches increased batter viscosity and consequently the batter pick up. Batters, with comparable viscosity were prepared by varying the solid/water ratio which gave the same batter pick up.The pasting properties of cross-linked starches showed that the higher the cross-linking the more resistant was the starch to gelatinization and granule disintegration. In batters with a constant solids/water ratio, batter with high cross-linked starch had more water loss during frying. Cross-linked starches had lower moisture content after storage and less oil was retained after frying. Crispness, measured instrumentally as sound intensity, was the highest for the high cross-linked starch at 1 and 20 min after frying.Batters prepared with the same viscosity were used to study the effect of cross-linked starches when the pick up was the same. To obtain comparable viscosities between the batters, the batter with native starch was prepared using the lowest mixing water content and the one with high cross-linked starch with the highest. The batter with the high cross-linked starch, although it had the highest addition of water, had the best crispness after frying.In conclusion, high cross-linking of wheat starch enhances crispness perception of deep-fried battered food.     

芭蕉芋氧化淀粉的制备与性质

采用正交法考察了淀粉悬浮液浓度、过氧化氢与催化剂用量、反应温度和反应时间对芭蕉芋过氧化氢氧化淀粉中羧基含量的影响,并比较了相同氧化剂用量下次氯酸钠、高锰酸钾、过氧化氢氧化淀粉的羧基含量和黏度。结果表明,制备芭蕉芋过氧化氢氧化淀粉的最佳反应条件为pH=7,淀粉悬浮液浓度46％,过氧化氢12％,硫酸铜0．048％,反应时间3h,反应温度50℃,在此条件下,制备的氧化淀粉羧基含量可达0．92％;次氯酸钠氧化效率高于过氧化氢和高锰酸钾;低羧基含量时次氯酸钠氧化淀粉的黏度大于过氧化氢和高锰酸钾氧化淀粉。