食品添加剂对面团玻璃化转变温度的影响

实现食品的玻璃化贮藏是提高食品质量的有效手段。本研究利用差示扫描量热仪探讨了适用于面团玻璃化转变温度测量的扫描程序、研究了水分含量及若干食品添加剂对面团玻璃化转变温度的影响规律。结果表明,多次扫描法是一种可行的面团玻璃化转变温度的测量方法;水分添加量对面团的玻璃化转变温度有明显影响。在本研究的范围内,面团的玻璃化转变温度随面团水分含量的增加而明显下降。食品添加剂对面团的玻璃化转变温度有显著影响。添加抗坏血酸、海藻糖及明胶时,均可不同程度的使面团的玻璃化转变温度有所升高,这对于在现有储存条件下(-18℃)实现面制品的玻璃化保存,提高速冻面制品的稳定性,改善速冻面制品的质量有重要的应用价值。     

速冻发酵面制品技术

正速冻发酵面制品不仅卫生、食用方便,还具有丰富的营养。因此,速冻食品生产工业得到迅速发展,但随着市场的激烈竞争,速冻冷制品的质量无法得到保证,很多生产厂家也未构建合理的执行标准,导致在工艺生产中难以控制,从而降低速冻冷制品质量的稳定性。影响速冻发酵面制品的质量因素主要为加工与保存,本文     

速冻食品的玻璃化加工及保藏

介绍了速冻食品的玻璃化转变及玻璃化转变温度的测定方法,另外对玻璃化理论今后在速冻食品加工与保藏中的应用方向和研究重点也进行了探讨。     

论食品的玻璃化保藏

食品聚合物科学认为：在玻璃态下，造成食品品质变化的一切受扩散控制的反应，其速率均十分缓慢，甚至不会发生。食品发生玻璃化转变时的温度（称为玻璃化转变温度），可利用差式扫描量热法来测定。玻璃化保藏可以最大限度地保存食品原有的色、香、味、形以及营养成分。目前玻璃化在食品中的应用研究包括：淀粉的玻璃化相变研究，玻璃化在冰淇淋、冷冻水果及传统糯米制品中的应用研究等。如何进一步改进检测技术，深入研究食品体系的玻璃化转变动力学、热力学以及食品在贮藏期间品质的变化，以便确定货架稳定的动力学模型，有效地提高食品的品质及稳定性将是今后研究的重点。     

速冻面米制品行业现状与前景展望

随着生活节奏加快，家务劳动社会化趋势更加明显，速冻面米制品以其食用方便、安全卫生等特点受到很多消费者的喜爱，而消费升级叠加疫情影响则加速了速冻面米制品行业的发展，速冻面米制品成为发展最快的食品之一。综述了速冻面米制品行业的发展现状，并对速冻包点、速冻饺子、速冻汤圆这三大类速冻面米制品的工艺和行业现状进行了阐述，浅析了速冻面米制品的未来发展趋势，以期为速冻面米制品行业及企业发展提供一点参考。     

速冻面制品的质量问题及其对策

就目前市场上速冻面制品中普遍存在的一些质量缺陷问题，结合速冻基本原理，对影响因素进行了分析，提出了一些质量改良对策。     

变性淀粉在面制品中的应用

随着经济的发展,生活节奏的加快,作为主食的面制品,其品种和数量将不断增加,这是一种必然趋势,提高面制品的质量也是客观的要求.变性淀粉以其良好的性能在食品加工中广泛应用.现对其在烘焙制品、面条以及速冻食品中的应用作一综述.     

卫生部公布《速冻面米制品》食品安全国家标准

速冻面米制品是我国居民日常消费的重要食品。为规范速冻面米制品生产经营,确保速冻面米制品安全,保护消费者健康,根据《食品安全法》及其实施条例规定,卫生部在原《速冻预包装面米食品卫生标准》(GB19295-2003)实施基础上,组织制定公布了食品安全国家标准《速冻面米制品》(GB19295-2011),将于2011年12月21日起正式施行。《速冻面米制品》在制定过程中,     

基于动态机械分析仪的馒头玻璃化转变温度测定条件的研究

食品的玻璃化转变温度是控制食品质量和稳定性的关键。食品在玻璃化转变温度下进行保存,可最大限度保存其原有色、香、味、形及营养成分,从而延长食品保存期,提高食品保存过程中质量。基于此,研究用动态机械分析仪(DMA)对馒头的玻璃化转变温度进行了测定。结果表明:在不同测定条件下得到的馒头玻璃化转变温度不同。在振幅变化,其他测定条件不变时,馒头的玻璃化转变温度随振幅的增大而减小;在温度变化速率改变,其他测定条件不变时,馒头的玻璃化转变温度随温度变化速率的增大而增大。综合得出在振幅20μm,温度变化速率2℃/min下测得的馒头玻璃化转变温度较客观准确。因此,最佳测定是其他条件不变,振幅20μm,温度变化速率2℃/min。     

玻璃化转变与食品的加工、储存和品质

论述了食品的玻璃化转变与其加工、储存工艺及产品品质间的关系。重点介绍了玻璃化转变对食品的冷冻及干燥工艺的影响,淀粉玻璃化转变对食品的品质的影响,冰淇淋的冷冻保藏和玻璃化法超低温保存等。     

三种杂粮在速冻水饺加工中的应用研究

把黄豆粉、燕麦粉、玉米粉添加在速冻水饺皮中,研究杂粮添加量对混合粉最佳加水量、速冻水饺冻裂率和食用品质的影响。结果显示：香满园饺子粉、黄豆粉、燕麦粉、玉米粉的最佳加水量为0.43、0.33、0.63、0.53g/g;随着杂粮用量的增多,添加燕麦粉和玉米粉的速冻水饺的冻裂率呈上升趋势,添加黄豆粉的速冻水饺的冻裂率先上升后下降;黄豆粉、燕麦粉和玉米粉的添加量对速冻水饺感官总分的影响在1‰水平上均是极显著,判定系数R2分别为0.936、0.990和0.994,回归模型分别为y=90.404-61.413x、y=90.094-122.477x和y=94.366-101.65x。     

Role of glassy state on stabilities of freeze-dried probiotics

High viability of dried probiotics is of great importance for immediate recovery of activity in fermented foods and for health-promoting effects of nutraceuticals. The conventional process for the production of dried probiotics is freeze-drying. However, loss of viability occurs during the drying and storage of the dried powder. It is believed that achieving the "glassy state" is necessary for survival, and the glassy state should be retained during freezing, drying, and storage of cells. Insight into the role of glassy state has been largely adopted from studies conducted with proteins and foods. However, studies on the role of glassy state particularly with probiotic cells are on the increase, and both common and explicit findings have been reported. Current understanding of the role of the glassy state on viability of probiotics is not only valuable for the production of fermented foods and nutraceuticals but also for the development of nonfermented functional foods that use the dried powder as an adjunct. Therefore, the aim of this review is to bring together recent findings on the role of glassy state on survival of probiotics during each step of production and storage. The prevailing state of knowledge and recent finding are discussed. The major gaps of knowledge have been identified and the perspective of ongoing and future research is addressed.     

基因、灌溉和贮藏对小麦蛋白质理化特性影响的研究进展

蛋白质理化特性是衡量小麦制品品质的重要指标,其受小麦品种、灌溉条件、籽粒和面粉贮藏时间及温湿度的显著影响。高分子量谷蛋白亚基表达量与蛋白质理化特性正相关。灌溉条件显著影响小麦蛋白质理化特性,适当的节水处理有利于蛋白质积累和麦谷蛋白大聚体大颗粒形成。贮藏时间和温湿度均显著影响小麦蛋白质理化特性;短期贮藏中,贮藏时间与麦谷蛋白大聚体理化特性正相关;随贮藏时间的延长,麦谷蛋白大聚体含量和面团黏弹性逐渐降低;与低温低湿条件相比,高温高湿条件下小麦各指标在贮藏过程中变化幅度大。后期可结合籽粒和面粉贮藏及麦谷蛋白大聚体流变学特性和形貌开展研究,以期为籽粒和面粉贮藏质量,乃至面制品质量控制提供理论依据。     

类胡萝卜素的氧化降解及其对面粉品质的影响

类胡萝卜素是一类具有众多特殊功能的物质,面粉及其原料中含有丰富的类胡萝卜素。但类胡萝卜素在面粉的贮藏和加工过程中,会因各种途径而氧化降解生成无色的紫罗兰酮、假紫罗兰酮、二氢弥猴桃内酯和氧化异佛尔酮等具有特征香气的产物,促使面粉及其制品的色泽改善和香气特征的形成,并对提高其品质等产生有益的影响,对开发营养丰富、香气宜人、滋味佳的新型主食类食品有重要启迪。本文就此进行综述,并对类胡萝卜素的氧化降解途径、降解机理和主要降解物香气特征及其对面粉与面粉制品品质的影响等进行重点讨论,还对面粉中类胡萝卜素深度利用及氧化降解研究存在的问题等作出展望。     

Characterization of deep‐fat frying in a wheat flour–water mixture model using a state diagram

BACKGROUND: Crispness is an important characteristic to be controlled in deep‐fat fried products. The physical state of food polymers influences the development of cellular structure and textural qualities of fried food. Glassy state is believed to play an important role in the mechanical properties of low‐moisture food. Therefore, an understanding of the physicochemical phenomena in the development of fried food structure using a state diagram of the frying process is discussed. RESULTS: Wheat flour models containing 400 and 600 g kg^?1 initial moisture content were fried in frying oil at 150 °C for 1–7 min. Thermal properties of wheat flour, structure alteration and textural properties of fried samples were evaluated. The porous structure continuously enlarged when the sample was in the rubbery state. As the frying time was prolonged, the state of the product became glassy due to a decrease in water content, resulting in the ceasing of porous enlargement. Conclusion: The results revealed that physicochemical changes during frying influence the alteration of microstructure and quality of fried food, and the state diagram could be applied to explain the formation of microstructure during the frying process and used as a decision‐making tool to choose the proper conditions to provide desirable qualities in fried food. Copyright © 2007 Society of Chemical Industry     

Influence of Roasting on the Water Sorption Isotherms of Argentinean Algarroba (Prosopis alba Griseb) Pods

Prosopis alba is an arboreal legume that occurs naturally in Argentine. Its fruits (algarroba or Prosopis pods) are dried or roasted, ground and then used in foods and feeds. The influence of roasting process on the water sorption isotherms of Prosopis pod flour at three storage temperatures was studied. The equilibrium data for each sorption isotherm were determined by the standard static gravimetric method. Experimental values were fitted to the BET and GAB sorption models. Type II isotherms were obtained according to Brunauer classification. The calculated isosteric heats of sorption (Qs) near the monolayer moisture content were 7.30 and 7.68 kJ/mol for raw and roasted flour, respectively. The results showed that roasting did not significantly change the behavior of the products with regard to water adsorption, although a slight reduction of the tendency to humectation was observed, this being somewhat less spontaneous. In this aspect, the stability of Prosopis flour is similar in the raw and roasted states.     

Cassava as a non-conventional filler in comminuted meat products

Cassava (Manihot esculenta) was used as an unconventional filler to produce affordable comminuted meat products that stored well under tropical conditions without refrigeration. The study involved two experiments. In experiment 1, five different emulsion-type pork sausages containing 5.4, 9.0 and 10.0% mould-free cassava flour, 5.4% crude full fat soy flour and a control without filler were assessed 0 and 7 days after preparation. A 40-member taste panel sensorily assessed the products in a 5 × 2 factorial (treatment × storage occasion) experiment based on the external appearance of the uncooked products and the external and internal colour, consistency, texture, aroma and taste of the cooked products. Although the panel judged products with 5.4% cassava flour as the best, the 9% inclusion level of cassava flour was found not to compromise the organoleptic qualities of the product. At this level 54 000 cedis (US$150) was saved on the cost of producing 1t of the product. In experiment 2, the sausages were pasteurised at 80 °C for 1 h and stored in a 4:1 vinegar-sugar solution or a 1:1:50 vinegar-sugar-water solution at 5 and 30 °C. Storage in 4:1 vinegar-sugar medium arrested bacterial growth over the 7-day monitoring period. It was concluded that 9% cassava flour could conveniently replace fat in comminuted meat products and a combination of pasteurisation and storage in vinegar-sugar solution is an effective method of storage of such products in the tropics.     

木薯全粉对饼干储藏期品质和质构特性的影响

研究了木薯全粉对饼干储藏期品质和质构特性的影响,以不同比例木薯全粉替代低筋面粉制作饼干,对其理化和质构指标进行评价。结果表明:添加木薯全粉使得饼干的明亮度下降,色泽变黄。木薯全粉可降低储藏期饼干的水分含量和吸水率,提高脆性。其中,木薯全粉与低筋面粉比例为30/70时,饼干在储藏期内水分含量、咀嚼性和硬度最低,脆性最高。当木薯全粉与低筋面粉的比例大于40/60时,与对照组相比,饼干的硬度、弹性和咀嚼性升高,饼干的品质下降。     

QUALITY OF SWEETPOTATO FLOUR DURING PROCESSING AND STORAGE

Sweetpotato flour can easily be promoted as a substitute for wheat flour in sweet baked products and can also be used for its high carotenoid content. However, the price of the sweetpotato flour must be competitive with wheat flour and be of good quality. This article defines and describes the different quality characteristics of sweetpotato flour. After an overview of the different steps and equipment used in the small-scale processing of sweetpotato flour, the influence of the different processing steps and storage on the quality characteristics are reviewed.     

低温液态速冻技术及其在水产品加工中应用研究进展

文章介绍了低温液态速冻技术的作用原理与技术特点,论述了所用载冷剂的研发情况,重点总结探讨了低温液态速冻技术在水产品加工中的应用研究现状、存在的技术问题与发展趋势。