Extrusion of corn grits containing various levels of hydrocolloids

Fourteen hydrocolloids, locust bean, agar, guar, alginate, tragacanth, carrageenan, xanthan, pectin, gelatin and Methocels A4M, E4M, F4M and K4M were dry blended with corn grits at levels of 0.1, 0.5 and 1.0%. Twenty percent moisture was added and each product extruded in a Brabender Model PL-V500 laboratory extruder at temperatures of 50, 75, 100, 125 and 150°C with a 1:1 screw operating at 100 rpm. Locust bean, agar, guar, alginate, arabic and Methocels E4M, F4M and K4M significantly lowered torque at an extrusion temperature of 50°C, but did not in general produce significant reductions at higher extrusion temperatures. In contrast, tragacanth, carrageenan, xanthan, pectin, gelatin and Methocel A4M did not significantly reduce torque over the concentrations and conditions evaluated during the extrusion of corn grits. All the Methocel derivatives lowered yield at low extrusion temperatures. No gum significantly increased yield over the entire extrusion temperature range evaluated. Therefore, certain gums can significantly reduce torque without influencing yield during the extrusion of corn grits.     

Stability of zearalenone during extrusion of corn grits

The effects of extrusion cooking on the stability of zearalenone (ZEN) in spiked (4.4 microg/g) food-grade corn grits were investigated using a twin screw extruder. A ground rice culture material containing a high level of ZEN was used to spike the corn grits. The extrusion variables were screw type (mixing and nonmixing), temperature (120, 140, and 160 degrees C), and moisture content (18, 22, and 26%). Both unextruded and extruded samples were analyzed for ZEN by high-performance liquid chromatography. Extrusion cooking of the corn grits resulted in significant reductions of ZEN in grits extruded with either mixing screws or nonmixing screws, but use of mixing screws was somewhat more effective (66 to 83%) overall than nonmixing screws (65 to 77%). Greater reduction of ZEN was observed at either 120 or 140 degrees C than at 160 degrees C. The moisture content of corn grits was not a significant factor affecting reduction of ZEN during extrusion with either mixing or nonmixing screws.     

甜玉米穗轴提取水溶性木聚糖的研究

旨在寻找一种甜玉米穗轴中水溶性木聚糖的提取和纯化方法。以甜玉米穗轴为原料,采用酸预处理高温蒸煮法提取木聚糖,正交实验后获得提取方法的最佳条件,并验证其提取率。木聚糖液经脱色、脱蛋白处理后,使用Capto Q阴离子交换树脂对木聚糖液进行纯化。结果如下：3g／L的H2SO4浸泡12h后,料液比为1：10,蒸煮温度为150℃,蒸煮时间为60min,提取率为27．32％。柱层析纯化后,木聚糖提取液的收率为51．8％,冻干粉木聚糖含量为82．7％。本文对甜玉米穗轴的木聚糖提取和纯化工艺进行了可行性研究和数据支持。     

鲜食甜玉米甜酒酿罐装食品的工艺研究

对鲜食甜玉米甜酒酿罐装食品的发酵工艺和罐装食品内容物的配比进行试验研究.试验结果表明:鲜食甜玉米甜酒酿发酵的最佳工艺条件为:甜酒曲用量1.0%、发酵温度25℃、发酵时间4d、料液比1:0.8;鲜食甜玉米甜酒酿罐装食品内容物最佳配比为:甜酒醪与水的比例为1:2,加糖量8%.产品可溶性固形物为8.5%,酒精度≤1.5°.     

甜玉米饮料的研制

以甜玉米为原料,采用α-淀粉酶、糖化酶酶解工艺,水解甜玉米中的淀粉,生产出澄清透明、具有甜玉米特有香味的澄清型甜玉米饮料,并研究了混浊型甜玉米饮料的加工工艺和稳定性,从而确定了产品的工艺方案。     

甜玉米蛋糕的研制

研究了添加甜玉米制作乳化蛋糕的生产工艺过程和工艺条件;通过单因素实验和正交实验探讨蛋糕生产中甜玉米添加量、蛋粉比、乳化剂用量、加水量四因素对蛋糕品质的影响,从而确定了甜玉米蛋糕的最佳配方:面粉100％,鸡蛋140％,甜玉米8％,砂糖90％,水23％,乳化剂6％。     

脱胚玉米糁在啤酒酿造中的应用

脱胚玉米糁因分布广泛、价格低廉及富含淀粉和蛋白质等原因成为替代大米的重要潜在啤酒辅料。该研究对不同粒径玉米糁及其他辅料的各项指标进行了对比分析,通过200 L中试发酵,研究脱胚玉米糁的酿造特性,分析其对啤酒风味品质的影响。结果表明,脱胚玉米糁的粒径不仅对其浸出率有较大影响,而且也影响其脂肪含量和脂肪酸值的变化;粒径为900~600μm范围内的脱胚玉米糁可以替代大米用作啤酒酿造的辅料,且在风味及感官品评上均表现良好,与大米辅料的啤酒品质相似。发酵过程理化指标、成品酒风味物质组成以及感官品评等结果表明,合适粒径的脱胚玉米糁是一个良好的啤酒酿造辅料,能够作为大米辅料的替代品。     

Reduced toxicity of fumonisin B1 in corn grits by single-screw extrusion

Corn grits spiked with 30 microg/g fumonisin B1 and two batches of grits fermented with Fusarium verticillioides (batch 1 contained 33 microg/g, and batch 2 contained 48 microg/g fumonisin B1), which were extruded by a single-screw extruder with and without glucose (10%, dry weight basis) supplementation were fed to rats. Control groups were fed uncontaminated grits. Extrusion with glucose more effectively reduced fumonisin B1 concentrations of the grits (75 to 85%) than did extrusion alone (10 to 28%). With one exception, the fumonisin B1-spiked and fermented extrusion products caused moderately severe kidney lesions and reduced kidney weights, effects typically found in fumonisin-exposed rats. Lesions in rats fed the least contaminated grits (batch 1) after extrusion with 10% glucose were, however, significantly less severe and not accompanied by kidney weight changes. Therefore, extrusion with glucose supplementation is potentially useful for safely reducing the toxicity of fumonisins in corn-based products and studies to determine the optimal conditions for its use are warranted.     

甜玉米汉堡包的开发研究

以小麦粉和鲜甜玉米为主要原料,添加酵母、糖、改良剂等辅料,采取二次发酵法生产甜玉米汉堡包;并通过单因素实验和正交实验确定了甜玉米汉堡包生产最佳配方为面粉100%、甜玉米浆16%、酵母1.3%、糖14%、水48%、改良剂0.8%、盐1.4%、奶粉3%、奶油5%。该产品具有独特的风味和良好的营养保健作用,市场前景广阔。     

The effect of various hydrocolloids on some physical properties of extruded corn grits

Fourteen hydrocolloids including Methocels (A4M, E4M, F4M and K4M), locust bean, guar, agar, arabic, alginate, tragacanth, carrageenan, xanthan, pectin, and gelatin gums were extruded at levels of 0, 0.1, 0.5 and 1.0% with corn grits in a Brabender Model PL-V500 extruder at barrel temperatures of 50, 75, 100, 125 and 150°C with a 1:1 screw operating at 100 rpm. Resulting products were evaluated for density, breaking strength and water absorption. Significant differences were found as influenced by hydrocolloid type/amount and extrusion temperature. In general, hydrocolloid additions significantly increased product density and either increased or decreased breaking strength and water absorption.     

甜玉米乳饮料的生产工艺及稳定性的研究

为了获得风味和口感俱佳,营养全面及状态稳定的甜玉米乳饮料,通过正交试验、感官评定和稳定性试验对玉米乳饮料生产工艺和稳定性进行了研究.试验结果表明:通过四因素三水平正交试验设计,原辅料配比在甜玉米∶白砂糖∶奶粉=10% ∶ 7% ∶ 0.5%,甜玉米乳饮料风味最佳,口感最好,感官评分最高;以0.1%黄原胶和0.1%海藻酸钠为稳定剂,0.05%单甘酯,0.1%蔗糖酯为乳化剂,稳定效果最好;为了获得最佳稳定性,料液应在70℃,20MPa下均质.经30天贮藏试验证明产品稳定性极佳.     

Physical properties of extruded corn grits with corn fibre by CO2 injection extrusion

Corn grits and corn fibre mixed at different ratios (0/100, 15/85 and 30/70) were extruded at different melt temperature (90, 105 and 120 °C) using extrusion with and without CO₂ injection. Increasing melt temperature also significantly improved physical properties of extrudates in both non-CO₂ and CO₂ injection (200 mL/min) extrusion process. The injection of CO₂ in the extrusion process showed similar effect on physical properties of extrudates at the lower melt temperature (90 and 105 °C), whereas it exhibited opposite trend at higher melt temperature (120 °C). At the lower melt temperature, the surface of extrudates with the CO₂ injection was smoother and lower fracturability, and the cross sectional microstructure was more uniform. The addition of corn fibre decreased the expansion index, bulk density and breaking strength on the same extrusion condition. In addition, non-uniform and more broken cross-sectional microstructure was observed by the addition of corn fibre.     

冷藏条件下甜玉米的糖份变化

在6℃温度贮藏5d后,3个品种甜玉米的总糖含量分别下降19.7%、25.7%和9.5%。其中蔗糖含量在贮藏后有较大下降,果糖和葡萄糖含量也都下降,麦芽糖含量在贮藏后有较大上升。糖度计读数(癇rix)不能用来估测玉米中的糖份含量。     

改性甜玉米发酵乳的研制

通过单因素和正交实验确定了改性甜玉米发酵乳的发酵工艺条件。结果表明,改性玉米浆与鲜乳以1︰1.5的质量比混合,加入质量分数为3%蔗糖+3%乳糖,稳定剂的添加量为0.2%果胶+0.1%单甘酯,选用保加利亚乳杆菌和乳酸链球菌1︰1的比例按4%的接种量接种,在43℃条件下发酵7 h,可得到质地均匀、口感细腻、具有甜玉米清香的发酵乳。     

甜玉米酸乳饮料的研制

以甜玉米为原料与酸奶调配研制营养风味俱佳的甜玉米酸奶保健饮料.通过单因素实验结果表明,制作出的产品风味口感和稳定性均较好.实验对饮料配方及稳定性等关键因素进行了较详细的研究和探讨.经多次实验和感官鉴评确定,饮料的最佳配方为酸奶30％,甜玉米汁15％,蔗糖8％,柠檬酸0.02％.单一的稳定剂稳定效果很差,选用复合稳定剂.最佳参数组合:果胶0.15％,CMC0.3％,单甘酯0.04％,黄原胶0.02％,甜玉米酸乳饮料稳定性最好.