中国科学院机构知识库网格
Chinese Academy of Sciences Institutional Repositories Grid
谷物汽爆处理及其加工工艺的研究

文献类型:学位论文

作者孔峰
答辩日期2020-09-01
授予单位中国科学院大学
导师陈洪章
关键词汽爆,预处理,麦麸,全麦粉,加工工艺
学位名称博士
学位专业生物化工
英文摘要

谷物加工业是一个与三农问题密切关联,且与公众膳食营养及饮食安全息息相关的民生产业与国民健康产业。传统谷物加工片面追求精度和白度,致使谷物过度加工,造成了能源消耗较多、环境污染和资源浪费严重等问题;人们饮食日趋精细,罹患慢性疾病的风险显著提高。因此,研发和食用营养价值较高并具有一定保健功能的全谷物食品具有重要意义。然而,全谷物由于口感粗糙、保质期较短等因素限制了其推广使用,人们对谷物加工技术变革和工艺改进提出了新的要求。论文针对谷物加工过程营养损失较大、产品适口性不足等产业发展难题,在充分认知谷物原料特性的基础上,提出增加预处理环节、消除谷物麸皮对加工过程以及产品性能的不利影响是突破现有谷物加工技术难题的关键。汽爆是一种清洁高效的预处理技术,近年来在谷物加工领域受到广泛关注。在气相蒸煮阶段的热化学反应和瞬间爆破阶段的机械撕裂的双重作用下,汽爆可以对原料进行热化学-机械改性。论文对麦麸、小麦、高粱汽爆预处理及其加工工艺进行了研究,旨在为谷物加工提供一种新的预处理方法和一定的技术参考。论文取得的主要研究成果如下:(1)建立麦麸和重组全麦粉的汽爆稳定化新方法针对麦麸中脂肪酶活性较高,麦麸以及全麦粉中脂质容易发生水解酸败,影响麦麸和全麦粉贮藏性能、营养价值和感官品质等问题,建立了麦麸和重组全麦粉的汽爆稳定化方法。汽爆在压力0.8 MPa、维压时间5 min的条件下有效灭活麦麸的脂肪酶和过氧化物酶,灭酶效果优于常规蒸汽灭菌(0.1 MPa,20 min)。汽爆稳定化方法能够保持麦麸蛋白质、脂质含量,促进不溶性膳食纤维转化为可溶性膳食纤维,提高麦麸提取液总黄酮、总多酚的含量和抗氧化活性。此外,汽爆显著降低了麦麸和重组全麦粉贮藏过程中产生的脂肪酸含量,改善了麦麸和全麦粉的贮藏性能。(2)汽爆改善麦麸的理化性质,对馒头品质有改良作用针对麦麸中不溶性膳食纤维含量较高,影响面制品加工性能和产品口感等问题,采用汽爆处理改善麦麸的理化性质,并评估汽爆麦麸对面粉、面团和馒头品质的影响。汽爆麦麸中可溶性膳食纤维含量提高了66.67%,维持了蛋白质和淀粉含量。与未处理麦麸相比,汽爆麦麸持水力、水溶性指数、胆固醇和胆酸盐吸附能力分别提高了13.91%、30.77%、28.61%和70.83%。汽爆麦麸的添加对面团和馒头的质构性能有一定的积极影响,在添加量为10%时,小麦馒头的弹性和咀嚼性显著增加,硬化速率最小。(3)汽爆提高麦麸的膨化品质针对麦麸中不溶性物质含量较高,不利于挤压膨化、产品膨胀度较低等问题,首次采用汽爆技术作为麦麸挤压膨化的预处理方法,提高麦麸的膨化品质。与未处理麦麸膨化物相比,汽爆麦麸膨化物横向膨胀度提高了37.93%,粉碎后可以得到粒径更细的粉体。此外,汽爆显著提高了麦麸膨化物的总多酚含量(155.19%)和总黄酮含量(108.89%),提升了水溶性指数、膨胀力和阳离子交换能力。(4)建立汽爆麦麸粉碎新工艺针对麦麸韧性较大、难以粉碎成细小的颗粒以及粉碎过程能耗较高等问题,建立了汽爆麦麸粉碎工艺。汽爆(0.5 MPa,2 min)可有效地破坏麦麸致密结构,降低麦麸的力学性能,提高麦麸粉的出粉率和破壁率。与热风干燥处理(105 ℃,12 h)相比,汽爆在一定程度上降低了麦麸粉碎过程的电能消耗。此外,重组全麦粉粉质性能试验表明,汽爆麦麸具有良好的加工适应性。(5)建立汽爆全麦粉加工工艺针对全麦粉出粉率较低、粒度分布大、脂肪酶含量较高、加工适应性较差等问题,将汽爆引入小麦加工,建立了汽爆全麦粉加工工艺。汽爆破坏了小麦麸皮的结构,降低了小麦的咀嚼性,提高了全麦粉的出粉率。汽爆维持了全麦粉的基本营养成分和白度,与普通全麦粉相比,汽爆降低了脂肪酶酶活。汽爆全麦粉面条内聚性、弹性和咀嚼性分别提高了35.00%、26.00%和25.77%。(6)汽爆高粱全粉改善馒头的质构性能和食用品质针对高粱中含有较多的不溶性膳食纤维和单宁含量,造成高粱的食用品质较差等问题,将汽爆技术引入高粱加工。汽爆高粱不溶性膳食纤维和单宁含量分别降低了33.96%和13.58%,抗性淀粉、总多酚和总黄酮含量分别提高了109.28%、18.92%和39.01%。适量添加汽爆高粱全粉可改善小麦面团质构特性及馒头品质,汽爆高粱全粉的添加量为25%时,馒头硬化速率最低,食用品质较好。;Cereal processing industry is the livelihood industry and national health industry, which is closely related to the three rural issues, public dietary nutrition and safety. Traditional cereal processing blindly pursues precision and whiteness, which leads to over-processing of cereal, resulting in more energy consumption, serious environmental pollution and waste of resources. As people eat more refined diets, the risk of chronic disease is significantly higher. Therefore, it is of great significance to develop and eat whole grains with high nutritional value and certain health functions. However, due to its rough taste and short shelf life, the promotion and use of whole grains are limited. People put forward new requirements for the technological reform and the technical improvement of cereal processing. Aiming at the industrial development problems of cereal processing, such as high nutritional loss and inadequate product palatability, on the basis of fully understanding the characteristics of cereal materials, this study put forward that increasing the pretreatment process and eliminating the adverse effects of cereal bran on processing process and product performance were the key to break through the existing technical problems of cereal processing. Steam explosion is the clean and efficient pretreatment technology, which has been widely concerned in the field of cereal processing in recent years. The thermochemical and mechanical modification of raw materials can be carried out by steam explosion under the dual action of thermochemical reaction in gas cooking stage and mechanical tear in instant explosion stage. The steam explosion treatment and its processing technology for wheat bran, wheat grain and sorghum grain were studied in this paper in order to provide a new pretreatment method and a certain technical reference for cereal processing. The main research results obtained in this paper are as follows:(1) A new steam explosion stabilization method for wheat bran and reconstituted whole wheat flour was developed.Lipids in wheat bran and whole wheat flour are prone to hydrolysis and rancidity due to wheat bran contains more lipase activity, which largely affects the storage property, nutritional value and sensory quality of wheat bran and whole wheat flour. The new steam explosion stabilization method for wheat bran and reconstituted whole wheat flour was developed. Steam explosion was effective in inactivating lipase and peroxidase in wheat bran under the pressure of 0.8 MPa and residence time of 5min. The effect of steam explosion on inactivating enzyme was better than that of conventional thermal sterilization (0.1 MPa, 20 min). The steam explosion stabilization method can maintain the contents of protein and starch, promote the conversion of insoluble dietary fiber to soluble dietary fiber, and improve the total flavonoids, phenolics content and antioxidant activity of wheat bran extract. In addition, the accelerated storage experiments were conducted on wheat bran flour and reconstituted whole wheat flour. The content of fatty acids in wheat bran and reconstituted whole wheat flour during storage was significantly reduced by steam explosion, and the storage property of wheat bran and whole wheat flour was improved.(2) Steam explosion could improve the physical and chemical properties of wheat bran and the quality of steamed bread.Wheat bran has the high content of insoluble dietary fiber, which affects its bioavailability and processing performance. Steam explosion was used to improve the physical and chemical properties of wheat bran, and the effect of steam exploded wheat bran on the quality of flour, dough and steamed bread was evaluated. Soluble dietary fiber content of steam exploded wheat bran increased by 42.86%. At the same time, protein and lipid content were maintained. Compared with untreated wheat bran, water holding capacity, water solubility index, cholesterol and bile acid adsorption capacity of steam exploded wheat bran increased by 13.91%, 30.77%, 28.61% and 70.83%, respectively. The addition of steam exploded wheat bran had a positive effect on the texture of dough and steamed bread. When the added amount of steam exploded wheat bran was 10%, the springiness and chewiness of steamed bread increased significantly, and the hardening rate was the lowest.(3) Steam explosion could improve the expansion quality of wheat bran.Wheat bran with high content of insoluble substances is not conducive to extrusion, which leads to the low expansion ratio. Steam explosion was first used as a pretreatment method for extruding of wheat bran to improve the expansion quality. Compared with untreated wheat bran extrudate, the horizontal expansion ratio of steam exploded wheat bran extrudate increased by 37.93%. The powder with finer particle size can be obtained by grinding the steam exploded wheat bran extrudate. In addition, the content of total phenolics (155.19%) and total flavonoids (108.89%) in wheat bran extrudate was significantly increased by steam explosion. Steam explosion improved the water solubility index, swelling capacity and cation exchange capacity of wheat bran extrudate.(4) A grinding process for wheat bran treated by steam explosion was established.Wheat bran with high toughness is difficult to be grinded into small particles and which leads to high energy consumption in grinding process. The grinding process of wheat bran treated by steam explosion was established. Steam explosion (0.5 MPa, 2 min) can effectively destroy the dense structure of wheat bran, reduce the mechanical properties of wheat bran, and improve the yield and cell wall breakage ratios of wheat bran powder. Compared with hot-air drying treatment (105 °C, 12 h), steam explosion can reduce the energy consumption in wheat bran grinding process to a certain content. In addition, the farinograph properties of recombinant whole wheat flour showed that steam exploded wheat bran had good processing adaptability.(5) A processing technology for steam exploded whole wheat flour was established.The flour yield is low, the particle size distribution is broad, the lipase activity is high and the processing suitability is poor in whole wheat flour. Steam explosion was introduced into processing technology for whole wheat flour. The structure of wheat bran was destroyed by steam exploded. Steam exploded reduced the chewiness and the energy consumption of grinding process of wheat grain. Compared with common whole wheat flour, steam explosion maintained the basic nutrients and whiteness of whole wheat flour, and decreased the lipase activity. The cohesiveness, springiness and chewiness of noodles prepared by steam exploded whole wheat flour increased by 35.00%, 26.00% and 25.77%, respectively.(6) Steam exploded whole sorghum flour could improve the textural property and edible quality of steamed bread.Sorghum food has poor edible quality due to high insoluble dietary fiber and tannin content. Steam explosion was introduced into sorghum processing. The contents of insoluble dietary fiber and tannin of steam exploded sorghum decreased by 33.96% and 13.58%, respectively. And the content of resistant starch, total phenolics and flavonoids increased by 109.28%, 18.92% and 39.01%, respectively. The added steam exploded whole sorghum flour improved the textural property of wheat dough and the quality of steamed bread. When the added amount of steam exploded whole sorghum flour was 25%, the hardening rate of steamed bread was the lowest and the edible quality was better. 

语种中文
源URL[http://ir.ipe.ac.cn/handle/122111/49669]  
专题中国科学院过程工程研究所
推荐引用方式
GB/T 7714
孔峰. 谷物汽爆处理及其加工工艺的研究[D]. 中国科学院大学. 2020.

入库方式: OAI收割

来源:过程工程研究所

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