冷冻及微波复热条件对预油炸面拖食品脆性的影响

利用微波工作站实时测定预油炸冷冻面拖食品在冷冻和微波复热过程中内部温度的变化,研究了不同冷冻方式、冷冻速率、冻藏温度及微波复热参数条件对产品脆性的影响.对微波预油炸面拖食品微波复热过程中功率和时间时产品脆性的影响也进行了探讨.结果表明,冷冻速率和冷藏温度与产品脆性存在正相关,相同温度下强制通风冷冻的产品脆性高,强制通风样品的超微结构较自然降温样品平整致密,水分阻隔性能力强.     

改善可微波预油炸食品表皮脆性的研究进展

随着微波炉的普及、人们生活节奏的加快,以及人们对食品品质更营养、更卫生、更方便的追求,可微波预油炸食品正逐渐成为方便食品发展的主流。然而预油炸及焙烤食品经过微波复热后,表皮脆性及焦糊感部分丧失,产生表皮失脆现象,使产品品质大打折扣。本文讨论了可微波预油炸食品表皮失脆现象产生的原因,提出改善产品品质的方法,并针对近年来相关配料的研究进展,借鉴国内外研究经验,提出新的微波表皮脆性改良剂以及微波食品品质控制的方法。     

面糊组分对预油炸微波复热鸡米花品质及水分分布特性的影响

针对鸡米花在微波复热过程中水分“外迁”和油分“外浸”造成脆性降低的问题,研究不同面糊组分,羟丙基羧甲基纤维素（hydroxypropyl methylcellulose,HPMC）和麦芽糊精对预油炸及微波复热后鸡米花含油量、含水量及分布、脆性、颜色、感官品质的影响,以期提高鸡米花微波复热后的脆性及品质特性。结果表明,面糊中添加2%?HPMC和6%麦芽糊精显著降低了微波复热后鸡米花外壳中含水量的增加以及内芯肉中含水量的减少（P＜0.05）,同时使内芯肉T22向快弛豫方向移动,降低了自由水的移动性,同时微波后A22显著高于对照组（P＜0.05）,抑制微波过程中内芯肉中自由水向外壳的迁移,从而保证微波复热后鸡米花外壳脆性和内芯肉多汁性;添加2%?HPMC、6%麦芽糊精及两者复配的微波复热鸡米花外壳脆性较对照组均显著提高（P＜0.05）;但添加2%?HPMC的鸡米花外壳硬度最大,添加6%麦芽糊精的鸡米花含油量最高（P＜0.05）。当面糊中同时添加2%的HPMC和6%的麦芽糊精时,鸡米花经微波后其外壳脆性最好,硬度适中且无油腻感。该研究结果为裹粉类微波食品脆性及品质的改善提供了数据基础。     

可微波冷冻预油炸食品的研究进展

可使用微波炉重新加热的冷冻预油炸食品是目前最受消费者青睐的调理食品之一,但其加工过程中仍存在着许多问题。文章综述了预油炸食品在油炸、冷冻贮藏和微波复热三道工序中的品质控制以及改良措施,以期为可微波预油炸食品的加工提供参考。     

微波加热过程中油脂升温特性的研究

利用微波工作站实时测定微波加热时油脂升温情况以及不同冻藏时间的油脂经微波复热时的温度变化情况,考察了微波复热过程中油脂的种类和冻藏条件对油脂温度变化的影响。结果表明,大豆油、葵花籽油、花生油等6种植物油微波升温特性有差别:葵花籽油因不饱和脂肪酸含量较高,升温较快;花生油的不饱和脂肪酸含量较低,升温较慢。置于-20℃冻藏1d后,6种油脂微波复热曲线均会呈现S型,而且凝固点高的花生油复热最慢,到达0℃所需时间最长。将大豆油分别置于-20℃和-30℃连续冻藏一个月,冻藏温度越低对油脂微波复热温度变化影响越小,复热曲线越稳定;在同一冻藏温度下,冻藏时间越长对油脂复热影响越小。     

三种玉米淀粉对微波复热鸡米花品质特性的影响

本文研究了浸蘸液中三种玉米淀粉,包括普通玉米淀粉、糯玉米淀粉和玉米变性淀粉对微波复热鸡米花脆性及品质特性的影响。结果表明,添加玉米变性淀粉和糯玉米淀粉可以显著降低预油炸和微波复热后鸡米花外壳中油分含量(p0.05);添加糯玉米淀粉和玉米变性淀粉组的鸡米花外壳L*值和b*值显著低于普通玉米淀粉组样品(p0.05);经预油炸后添加普通玉米淀粉、糯玉米淀粉和玉米变性淀粉鸡米花外壳中水分分别为29.16%、28.43%和27.69%,经微波复热后分别为31.36%、29.45%和27.84%,添加玉米变性淀粉显著抑制了水分外迁(p0.05);从脆性测定结果可知,较普通玉米淀粉和糯玉米淀粉而言,添加玉米变性淀粉可以显著提高预油炸和微波复热后鸡米花外壳的脆性(p0.05)。综合感官评价,添加玉米变性淀粉的鸡米花外壳脆性最高,外壳油腻度最低,总体可接受性得分最高(p0.05)。在浸蘸液中添加玉米变性淀粉能够有效阻碍微波复热过程中鸡米花水分和油分外迁移,提高微波复热鸡米花的感官品质特性。     

可微波预油炸鸡块的开发

本文通过对油炸食品脆性的感官评定值与峰个数的测定和分析,确定了以感官评定值为主、质构仪测定的峰个数为辅的评价体系来检测可微波预油炸鸡的胞胜.本文从三方面来改善微波后预油炸鸡块的脆性:表皮中添加微波感受材料、内芯中添加亲水性强的物质以及选择最佳微波加热功率密度和加热时间.结果表明:增加丙三醇和羰基铁并不能增加微波后预油炸鸡块的脆性;内芯中添加0.2%的卡拉胶、0.3%的焦磷酸盐均使得微波后预油炸鸡块的脆性达到最大;3.25 W/g的功率密度加热22.8 S可使炸鸡块表皮的脆性保持最好.     

降低可微波预油炸食品含水量及含油量的研究进展

微波加热食品在生活中的应用越来越广泛,而我国可微波复热食品起步晚,不仅产品种类少,复热时风味的缺失以及表层失脆现象也限制了市场的发展。从可微波预油炸食品在预油炸过程、冻藏过程以及复热过程中含水量及含油量的变化,对改善失脆现象及降低含油量的方法做出总结,并对微波加热不均匀的现象做出分析,为可微波预油炸速冻食品在工业中的发展提供参考。     

改性蛋白对可微波预油炸春卷脆性的影响及其微波温升特性

冷冻预油炸春卷经微波加热后,由于内部水分迁移,产品脆性下降。分别考察了钙结合11S大豆蛋白、钙结合7S大豆蛋白、钙结合大豆蛋白对预油炸春卷皮脆性的影响,得出钙结合11S大豆蛋白效果最佳。测定以上三种蛋白质变性温度和钙结合量,对钙结合11S大豆蛋白的增脆机理做出初步解释。同时确定了采用25ml/kg的甘油加入量,使内外层体系同时在600W加热30s达到45℃,达到消费者直接食用的最适温度;研究了微波加热功率和时间对产品脆性的影响,确定了采用600W加热40s的组合。     

可微波预油炸食品的研究

微波食品是指应用现代加工技术,对食品原料采用科学的配比和组合,预先加工成适合微波炉加热或调制,便于食用的方便食品。微波食品加工简单化和方便化,适应现代人高效率、快节奏的生活方式。但是,由于微波加热本身所固有的缺点,使得速冻的预油炸食品在微波炉中复热时,产品表面"浸湿"、"浸油",失去了香酥松脆的良好口感。所以对可微波油炸食品的研制已成为传统食品工业化中的一个重要课题。     

改性大豆分离蛋白对微波复热鸡米花品质的影响

为解决微波复热后鸡米花表皮由于浸湿而失脆的问题,本研究向面糊层中添加了超高压均质-酶解复合改性大豆分离蛋白(UESPI),测定了鸡米花微波复热后外层的水分、油分,并分别以色差值,TPA分析中的正向峰数,面糊层孔洞结构为指标研究了面糊层中添加大豆分离蛋白对鸡米花色泽,脆度,表层微观结构的影响。结果表明,面糊中添加20%UESPI的鸡米花微波复热后,表层水分、油分显著下降(p<0.05),鸡米花呈金黄色泽,其微波复热后脆度与新鲜油炸鸡米花脆度相近(p>0.05)。SEM结果则显示面糊层结构致密、几乎无孔洞,有效的阻止了内芯水分、油分的外溢。本研究采用UESPI作为鸡米花面糊层配料,有效的提高了鸡米花微波复热后的脆性,极大的改善了鸡米花的感官特性。     

预煎炸冷冻食品锅贴的配方优化

对预煎炸微波冷冻冷冻锅贴面皮的品质改善进行了研究。通过筛选配方配料,确定添加脆性淀粉、瓜尔豆胶、羟甲基纤维素钠、大豆分离蛋白可以提高产品的酥脆性,改善微波复热后的"侵湿"现象,并确定了产品配方:中筋面粉100 g、脆性淀粉10 g、HPMC 1 g、大豆分离蛋白2 g、瓜豆尔胶1.5 g、油2.0 g、盐0.5 g、水50 mL。     

微波生产低油马铃薯片的工艺条件的探讨

通过单因素试验,对利用微波生产低油马铃薯片工艺中影响产品脆度、色泽和含油量的一些因素进行了探讨。结果表明:利用微波生产马铃薯片可以降低薯片含油量到20%以下;干燥前食盐水溶液浸泡处理(1.5%～2.0%食盐水溶液浸泡5min)和涂油前用豆奶粉裹衣处理,均能降低产品的含油量,提高马铃薯片的脆度;同时,适量的豆奶粉裹衣处理,能赋予产品良好的色泽,豆奶粉的用量6%比较适宜;冷冻处理能加深产品的色泽,但是对产品的脆度和含油量的影响不大。     

全麦速冻油条复热加工中风味与抗氧化特性

利用电子鼻和顶空固相微萃取气相色谱-质谱联用检测技术,分析不同复热加工过程中全麦粉和全麦速冻油条挥发性成分及指纹图谱变化,以及对其内部多酚类化合物含量和抗氧化特性的影响.结果表明不同加工阶段会产生不同的特征风味物质.在速冻油条预炸和复热的过程中,全麦粉中部分风味物质消失.预炸后全麦油条的醛类物质峰面积百分比高达50％以...     

Flavor Migration Out of Food Matrices: III. Migration of Limonene and Pyrazine in Formulated Dough Undergoing Microwave Reheating

ABSTRACT Cold-trap, on-line sampling was applied to investigate migration of flavor compounds in a solid food matrix subjected to microwave heating. The activation energy levels for migration of limonene, pyrazine, and water are 58.2, 51.5, and 46.4 kJ/mol, respectively. The results of microwave reheating of limonene-formulated dough showed no significant limonene concentration profile in the sample and less than 1% overall change in total limonene concentration. Because the flavor concentration used for this migration study is greater than the amount that would be added to real products, it can be concluded that after microwave reheating of flavor-formulated dough, limonene is very stable and significant losses do not occur.     

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.     

Bread crispness and morphology can be controlled by proving conditions

Bread crust crispness is lost when water migrates from crumb to crust during storage. To what extent water migration is influenced by morphology is not known. Therefore, the effect of crispy rolls morphology on crust crispness was studied. Crispy rolls were prepared at three proving volumes: 300 mL (short proving), 500 mL (control) and 800 mL (long proving). X-ray microtomography was used to characterize morphology.Water transport from crumb to crust was determined. Short proved crispy rolls showed lower rate of crust water uptake while longer proved rolls showed faster uptake during cooling down. Sensory analysis revealed higher crispness for short proved crispy rolls after the same storage time at low RH. We hypothesize that shorter proved crispy rolls with finer crumb morphology, more closed structure, smaller gas cells with less gas cells interconnections and a thicker crust have a significant positive effect on water uptake kinetics and crispness retention.