谷物组成对挤压膨化产品品质的影响

该实验以6种谷物(粳米、小麦、玉米、糯米、小米、燕麦)为原料,考察不同谷物原料组成成分与产品膨化特性之间的相关性。结果表明,挤压后谷物膨化制品的一些指标得到很大提高,如吸水性指数、水溶性指数;蛋白质含量及脂肪含量与膨胀度呈负相关,淀粉含量与膨胀度呈正相关,膨化制品中蛋白质及脂肪含量要控制在合理范围内;水溶性指数与蛋白质含量呈极显著正相关,与总淀粉含量呈极显著负相关;糊化度与总淀粉含量呈极显著正相关,与蛋白质、粗脂肪含量呈极显著负相关。粳米、小麦以及糯米的膨化特性要优于玉米、小米以及燕麦,其中糯米在膨胀度、体积密度、水溶性指数、糊化度、硬度以及脆度方面都表现较为优异,膨化性能最好。综上所述,6种谷物原料中,糯米、小麦和粳米的挤压特性较好,可作为挤压膨化的主要原料,玉米、小米以及燕麦可根据成本适量添加。     

挤压膨化处理对亚麻籽粕理化性质的影响

利用DSE-25型双螺杆挤出机对亚麻籽粕进行挤压膨化质量研究。结果表明，挤压膨化过程中亚麻籽粕的理化性质发生了改变。在高温、高压、高剪切力环境下，蛋白质变性，总膳食纤维部分降解，有毒成分生氰糖苷被消除，氨基酸和可溶性膳食纤维含量增加，游离脂肪和水分含量减少，淀粉发生糊化裂解，组织结构疏松均匀，水溶性指数升高，吸水性指数下降。     

挤压膨化豆渣理化性质的研究

以大豆豆渣为原料,采用双螺杆挤压膨化技术,对挤压膨化豆渣的理化性质进行研究.结果表明,豆渣经挤压膨化后,脂肪、淀粉含量略有下降,不溶性膳食纤维含量明显下降,可溶性膳食纤维含量显著提高,蛋白质含量几乎没有发生变化,豆渣发生变性;膨化豆渣的水溶性、膨胀性、乳化活性、乳化稳定性、起泡性、泡沫稳定性及流动性得到提高,阳离子交换能力无显著变化.     

挤压膨化对发芽糙米理化性质的影响

以发芽糙米为原料,分析了发芽糙米经过挤压膨化前后的淀粉、蛋白质和氨基酸组成等营养成分含量的变化,研究了挤压膨化对发芽糙米理化性质的影响。结果表明:挤压膨化后发芽糙米中的淀粉、蛋白质和脂肪含量弱有减少,还原糖含量增加,氨基酸含量和组成变化不明显。挤压膨化后,发芽糙米的吸水性和水溶性都分别比未膨化的高出1.28和0.78倍;容重明显降低,糊化度大幅提高;挤压膨化发芽糙米的RVA谱特征值中,热浆黏度、最终黏度和峰值时间较发芽糙米的升高,其他特征值均有所下降;发芽糙米经挤压膨化后变为网状多孔的结构。     

挤压膨化对糙米理化特性的影响

挤压膨化过程中，糙米的淀粉、脂肪、蛋白质、膳食纤维及植酸都发生了有益的变化，淀粉颗粒增大，淀粉颗粒间距加大，有利于生产新型糙米食品。     

挤压膨化玉米理化变化的研究

本文旨在通过对挤压膨化后的玉米从物理变化、化学变化进行研究，为挤压膨化技术在玉米深加工领域中的应用提供理论上的依据，玉米经过挤压膨化后，淀粉粒解体，糊精和还原糖含量增加，蛋白质变性，氨基酸和缩氨酸含量增加，脂肪减少，水溶性成分增加。     

玉米挤压膨化机理的研究

本文以经过挤压膨化后的玉米为研究对象，在膨化倍数、碘蓝值、α-化度、还原能力等指标上进行对照试验，得出结论：玉米经过挤压膨化后，淀粉粒解体，糊精和还原糖增加，蛋白质变性，氨基酸和缩氨酸含量增加，脂肪减少，水溶性成分增加，从而为挤压膨化技术在玉米深加工领域中的应用提供了理论依据。     

挤压膨化处理对婴幼儿米粉理化和体外消化特性的影响

为探讨婴幼儿米粉基料干法制造过程中挤压膨化处理对米粉特性的影响规律,对不同品种大米经挤压膨化得到米粉的理化和消化特性差异进行比较分析,结果表明:在相同挤压膨化条件下,不同大米之间淀粉组成差异明显,导致膨化度、吸水指数和水溶性指数差异显著(P<0.05);处理后由淀粉体外消化特性得出:早籼米中抗性淀粉含量最高,接近15%;糯米快速消化淀粉含量最低,小于75%。蛋白质消化特性结果显示,糯米制品的胃蛋白酶消化率和蛋白质总消化率均低于其它3种米粉,这可能是因糯米中蛋白质的结构和组成不同所致。研究结果为挤压膨化技术在米粉生产中的应用及对不同品种大米米粉的性能影响提供理论依据。     

原料组分对挤压膨化米果品质的影响

以籼米为主要原料,采用单螺杆挤压膨化机生产挤压膨化米果,研究原料的不同粒度、水分含量、脂肪含量、粗纤维含量、直链淀粉含量和白砂糖的添加量对挤压膨化米果的膨化度、密度以及感官品质的影响及其相关性.结果表明,原料的粒度420μm,水分质量分数为16.7%,脂肪质量分数为1.83%,粗纤维质量分数为2.39%,直链淀粉质量分...     

挤压膨化技术在酒精发酵中的应用

通过挤压膨化处理过的玉米,在高温、高压、高剪切力环境下,淀粉分子间的氢键撕裂,淀粉发生糊化、降解,生成小分子量物质,淀粉水溶性增加。含支链淀粉较高的玉米淀粉经过挤压处理,支链部分发生降解的几率明显高于直连部分,挤压对支链淀粉的降解类似于普鲁兰酶的作用,大大提高了出酒率。     

Wheat starch production,structure, functionality and applications—a review

Starch is the main component of wheat having a number of food and industrial applications. Thousands of cultivars/varieties of different wheat types and species differing in starch functionality (thermal, retrogradation, pasting and nutritional properties) are grown throughout the world. These properties are related to starch composition, morphology and structure, which vary with genetics, agronomic and environmental conditions. Starches from soft wheat contain high amounts of surface lipids and proteins and exhibit lower paste viscosity, whereas that from hard cultivars contain high proportion of small granules and amylose content but lower gelatinization temperature and enthalpy. Waxy starches exhibit higher‐percentage crystallinity, gelatinization temperatures, swelling power, paste viscosities and digestibility, but lower‐setback viscosity, rate of retrogradation and levels of starch lipids and proteins than normal and high‐amylose starches. Starches with high levels of lipids are less susceptible towards gelatinization, swelling and retrogradation and are good source of resistant starch, while that with high proportion of long amylopectin chains are more crystalline, gelatinize at high temperatures, increase paste viscosity, retrograde to a greater extent and decrease starch digestibility (high resistant and slowly digestible starch and low rapidly digestible starch).     

脱蛋白或脱脂对薏苡淀粉糊化和体外消化特性的影响

以薏苡为材料,制备脱淀粉颗粒相关蛋白(starch granule-associated proteins,SGAPs)、脱脂和脱SGAPs脱脂薏苡淀粉,探究了脱SGAPs和脱脂对薏苡淀粉糊化和体外消化特性的影响。结果表明,脱SGAPs和脱脂提高了薏苡淀粉的膨胀势、溶解度、快消化淀粉和慢消化淀粉,降低了1 045 cm^-1与1 022 cm^-1处峰强度比值、峰值黏度、谷值黏度、崩解值和抗性淀粉。脱SGAPs显著提高了薏苡淀粉的糊化转变温度、糊化焓,显著降低了糊化起始温度。脱SGAPs对淀粉短程有序结构和消化特性的影响大于脱脂,脱脂对薏苡淀粉的热力学性质无显著影响,脱SGAPs和脱脂对淀粉的晶型无显著影响。研究结果对于了解薏苡淀粉特性以及薏苡淀粉在食品加工中的应用具有潜在价值。     

非热加工技术对淀粉结构特性影响的研究进展

非热加工技术具有“绿色、安全、高效”等优点而被广泛应用于淀粉的改性。经非热加工技术改性后,淀粉颗粒形态、颗粒晶型、颗粒结晶度以及颗粒螺旋结构等结构特性的改变对其糊化特性、老化特性、溶解性、消化率等功能特性均产生相应的影响,而功能特性的改变可进一步扩大淀粉的实际应用范围。本文以球磨、脉冲电场、高压、超声波、辐照、等离子体6 种非热加工技术为主,综述非热加工技术改性淀粉结构的原理,指出非热加工技术对淀粉颗粒结构影响的重要性以及不同层次结构的改变对相应功能特性的相关影响,并对非热加工技术在淀粉深加工领域的应用提出展望。     

蛹虫草复合谷物杂粮膨化产品的工艺优化及糊化特性

目的:采用双螺杆挤压工艺制备蛹虫草复合谷物杂粮膨化产品,并研究蛹虫草对谷物杂粮膨化产品淀粉糊化特性的影响。方法:以大米粉、糯米粉、薏米粉、红豆粉、黄豆粉、蛹虫草粉为原料,按照一定比例混合制成蛹虫草复合谷物杂粮粉进行挤压膨化实验,并在单因素试验的基础上,选择物料水分含量、螺杆转速、进料速率、挤压温度为影响因素,产品径向膨化率、糊化度、水分含量、吸水性和水溶性指数为指标,设计正交试验,用极差分析法优化出蛹虫草复合谷物杂粮膨化产品的最佳工艺,并利用快速黏度仪测定谷物杂粮膨化产品和蛹虫草复合谷物杂粮膨化产品的淀粉糊化特性。结果:蛹虫草复合谷物杂粮膨化产品的最优工艺参数为物料水分含量16%、螺杆转速180 r/min、机筒的5段挤压温度80-90-120-140-165℃、进料速率15 r/min,此时蛹虫草复合谷物杂粮膨化产品的径向膨化率、糊化度、水分含量、水溶性和吸水性指数分别为3.015、84.32%、6.11%、29.65%、416.39%;与谷物杂粮膨化产品相比,蛹虫草复合谷物杂粮膨化产品峰值黏度、保持黏度、最终黏度、回生值显著下降。结论:蛹虫草复合谷物杂粮膨化产品挤压工艺可行,添加蛹虫草能够显著降低谷物杂粮膨化产品的糊化特征值,并抑制其淀粉分子的回生或重排。     

Effect of frozen storage on lipids and functional properties of proteins of dressed Indian oil sardine (Sardinella longiceps)

Changes occuring in lipids and functional properties of dressed oil sardine during storage at −20°C (±2°C) were investigated for 12 weeks. Significant (P 0.05) changes were observed in the lipids and functional properties of frozen stored oil sardine meat. The extent of lipid oxidation and hydrolysis was strongly associated with decreased protein solubility (P0.01). Decrease in protein solubility (PS) positively correlated (P0.05) with the decrease in emulsifying capacity (EC), relative viscosity (RV) of soluble protein extracts, water binding capacity and negatively correlated with the cook loss. A positive correlation (P0.001) was established between the PS and the ability of soluble proteins to emulsify and stabilise an emulsion. High positive correlation between SSP & EC (P0.001) and PS & EC (P0.001) revealed that myofibrillar proteins are the main protein that decide the emulsion properties.     

Significance of lipid binding on the functional and nutritional profiles of single and multigrain matrices

Lipid fractions and starch- and protein-lipid binding of single and blended oat, rye, buckwheat and wheat flour, dough and bread matrices were investigated, and results correlated with the functional and nutritional properties of the grain matrices during mixing and baking. Non-starch lipid was the most prominent fraction in terms of absolute content and as a percentage of total lipids. Free lipids, starch lipids and bound lipids were, respectively, the major, intermediate and minor lipid fractions in flours, doughs and breads. Great differences in total lipid content due to sampling result in divergences amongst lipid fraction content and distribution, especially for starch and bound lipid fractions. Lipids bound to proteins during dough mixing are translocated and bound to starch during baking. In blended samples, the higher fibre content seems to provoke a reduction of the lipid–protein and lipid–starch linkages due to interactions between fibres and endogenous biopolymers. Starch lipid showed the most significant correlations with parameters related to dough and bread performance during breadmaking, especially over the mixing step. Valuable fresh bread functional characteristics, such as high specific volume and high sensory score for softness and overall acceptability, correspond to a starch lipid’s increase due to mixing. The higher the free and starch lipids decrease by reason of temperature treatment—baking—the larger the starch hydrolysis and the higher β-glucans and total dietary fibre contents.     

挤压膨化对亚麻籽粕中化学成分及结构的影响

采用DSE-25型双螺杆挤出机对亚麻籽粕进行试验研究。结果表明,挤压膨化过程中物料化学成分和结构发生了复杂的物化变化。在高温、高压、高剪切力环境下,蛋白质变性,总膳食纤维部分降解,有毒成分生氰糖苷失活,氨基酸和可溶性膳食纤维含量增加,游离脂肪和水分含量减少,淀粉发生糊化、裂解,组织结构疏松均匀。     

Effect of alkaline pH-shift processing on in vitro gastrointestinal digestion of herring (Clupea harengus) fillets

The effect of alkaline pH-shift processing on herring (Clupea harengus) protein oxidation, salt solubility and digestibility, has been evaluated. For the latter, herring mince and pH-shift produced herring protein isolate, both raw and heat-treated, were digested using a static gastrointestinal in vitro model. The pH-shift process resulted in drastically lowered protein salt solubility and increased lipid oxidation while protein carbonyl formation was unaffected. Yet, no significant differences in the degree of hydrolysis (DH) were observed between mince and isolates after completed gastrointestinal digestion, something which was confirmed by a similar release of proteinaceous material <3 kDa and similar free amino acid profiles. The polypeptide profiles of digested samples however revealed that two peptides (33 and 36 kDa) were present in larger amounts in the digested protein isolate compared to the digested herring mince. The results indicate that alkaline pH-shift processing had limited quantitative influence on the gastrointestinal digestibility of herring proteins despite its negative effects on protein salt solubility and lipid oxidation.     

Investigations of the Great Northern Bean (Phaseolus vulgaris L.) Starch: Solubility, Swelling, Interaction with Free Fatty Acids, and Alkaline Water Retention Capacity of Blends with Wheat Flours

The solubility and swelling of Great Northern bean (Phaseolus vulgaris L.) starch was both temperature and pH dependent. Acetylation of starch decreased the solubility while oxidation increased the solubility as a function of temperature. Solubility of purified starch was highest at pH 6.0. Over a temperature range 60–90°C, acetylation increased swelling while oxidation reduced it. Both acetylation and oxidation resulted in reduced swelling of starch over a pH range 2–10. Addition of fatty acids (palmitic, stearic, and linoleic) to the purified starch reduced the Brabender Amylograph viscosity and raised the gelatinization temperature of starch. Replacement of wheat flours by starch increased the alkaline water retention capacity to a similar extent for the two flours tested.     

Chemical and physical modification of proteins by the hydroxide ion

Proteins are exposed to alkaline conditions during solubilization and/or purification, during food storage and processing, in removal of toxic constituents, and for characterization. During alkali treatment, there are changes in solubility and aggregation, hydrolysis, elimination reactions involving the side chains of certain amino acids, racemization of amino acid residues, addition of compounds to proteins, fragmentation of the peptide chain, as well as modification or elimination of nonprotein constituents. The rates of these reactions are affected by pH, temperature, cations (in some cases), ionic strength (in some cases), protein concentration, and to some extent by the specific nature of the protein. The general mechanisms and stoichiometry of these reactions are described. Other constituents of high protein foods also undergo reactions in alkaline solutions and the products of these reactions may in turn react with proteins. We have described the effect of alkali on enediol formation and fragmentation of carbohydrates, the hydrolysis of lipids in alkaline solution and effect on rate of peroxidation of the polyunsaturated fatty acids, the oxidation of amino acid residues, especially methionine, the oxidation of phenols to benzoquinones, and the catalytic effect of metal ions in alkaline solutions. Alkali treatment is also used in the specific modification of proteins to distinguish between O-glycosyl and amide-linked glycosyl groups, to effect specific cleavage of peptide bonds via beta elimination, in the formation of anhydrotrypsin, anhydrochymotrypsin, anhydrosubtilisin and thiol-subtilisin, and in formation of intrachain crosslinking in proteins.