部分糊化淀粉浆液黏度与浆液性能相关性分析

探讨部分糊化淀粉浆液黏度对浆液性能影响的规律。以玉米淀粉为原料,采用蒸汽升温方式分别在62℃~67℃制备了6种不同黏度的部分糊化淀粉浆液,对浆液的黏度、糊化度、结晶度、粒径和膨胀势进行测试,并应用SPSS统计软件的相关分析与线性回归分析功能对测试结果进行了相关性分析。结果表明:部分糊化淀粉浆液的黏度与结晶度呈负相关,结晶度随黏度的增大而降低;黏度与平均粒径、膨胀势呈极显著正相关,平均粒径和膨胀势值均随黏度的增加而明显增大;黏度与平均粒径、膨胀势呈明显的线性关系。认为通过相关性分析可以建立起部分糊化淀粉浆液的评价分析方法,运用此方法,可以直观、有效地对部分糊化淀粉浆液黏度性质进行评价分析。     

变性淀粉—丙烯酰胺接枝共聚物的制备及其对瓦楞纸的增强作用

以硝酸铈为引发剂，合成了氧化淀粉及可溶性淀粉等变性淀粉与丙烯酰胺的接枝共聚物，详细考察了引发剂用量及淀粉性质对单体转化率和接枝率的影响。结果发现，用氧化淀粉，可溶性淀粉等变性淀粉与丙烯酰胺接枝共聚，可获得比原淀粉高得多的单体转化率和接枝率。在瓦楞纸中的使用表明，添加０．５％的氧化淀粉一丙烯酰胺接枝共聚物可使瓦楞纸的环压强度增加５２％。     

Application of starch microcapsules containing essential oil in food preservation

Abstract

Consumers' pursuit to a healthy lifestyle has promoted people to develop new technologies that can prolong the shelf life of food without the use of preservatives. Compared with other types of preservation, edible microcapsules containing essential oils (EOs) are becoming more and more popular especially the starch microcapsules containing essential oil (EOs-starch microcapsules) because of their environmentally friendly, healthier characteristics and the ability to carry active ingredients. In addition, the EOs-starch microcapsules can also reduce the flavor influence and prolong the action time of essential oil on food through its slow release effect, which can promote the use of EOs in food. Understanding the different collocation of edible starch microcapsules and EOs and the related antibacterial mechanism will be more effective and targeted to promote the application of EOs in the real food system. The review focus on the contribution of EOs-starch microcapsules to prolong the shelf life of food products, (1) binding characteristics of EOs-starch microcapsules were analyzed, (2) systematically summarizing the main materials and methods for preparing the EOs-microcapsules, (3) specifically addressing the action mechanisms of EOs-starch microcapsules on microorganism, (4) discussing the applications of EOs-starch microcapsules in specific food.     

制粉对小麦粉营养品质影响机理研究现状

小麦制粉是利用机械力作用将小麦胚乳与皮层和胚逐步分离后,再将其胚乳研磨成粉的过程。小麦籽粒中营养物质分布不均匀,在制粉过程中,受制粉系统、机械力作用、筛理分级等因素的影响,胚乳出现不同程度的破碎,不同粒度级的小麦粉营养组分含量及分布也存在着一定差异。同时,随着胚乳的破碎,细胞壁破裂、淀粉与蛋白分离,营养组分和酶的作用位点更多的暴露,从而提高营养组分的消化性和生物利用率。本文综述了制粉过程的相关因素对小麦粉营养品质影响机理研究现状,以了解小麦制粉过程中各营养素的变化和损失,为后续制粉过程中充分保留营养素、提高营养素利用率提供参考。     

Starch determination in horticultural plant material by an enzymic-colorimetric procedure

The starch content of horticultural plant material (including leaves and woody tissues such as roots, stems, twigs, trunks and bark) was determined by an enzymic procedure. A heat-stable α-amylase and amyloglucosidase were used to hydrolyse the starch in the finely ground plant material to glucose. The glucose produced was measured colorimetrically using a coupled glucose oxidase/peroxidase reaction. Conditions necessary for maximum glucose recovery were established. Plant material analysed included samples from macadamia (Macadamia integrifolia Maiden and Betche, trunk and bark), mango (Mangifera indica L; stems and roots), lychee (Litchi chinensis Sonn; leaves, stems, twigs and roots), pineapple (Ananas comosus (L) Merrill; leaves, stems and roots) and nectarine (Prunus persica (L) Batsch var nucipersica (Suckow) C K Schneid; twigs, shoots, branches, limbs, roots and trunk). Starch values ranged from less than 14% to greater than 30%. The method allows assessment of variations in the starch content of perennial plants and may be used in crop management.     

Elucidation of structural difference in theaflavins for modulation of starch digestion

The relationship between structure and activity of theaflavins against human pancreatic α-Amylase was investigated by in vitro and in silico methods. The IC₅₀ and total energy value showed that inhibitory effects followed the order: theaflavin-3, 3’-di-O-gallate > theaflavin-3’-O-gallate > theaflavin-3-O-gallate > theaflavin. Inhibitory activity was depended on hydroxyl groups and galloyl moieties of theaflavins to interact with the catalytic residues of the active site of α-Amylase by hydrogen bonds and π–π (aromatic–aromatic) interactions. The galloylated theaflavin has higher binding affinity with α-Amylase than non-galloylated theaflavin. The study showed that theaflavins might act as natural enzyme inhibitors with potential health benefits, which provide a foundation for designing novel functional food for effective controlling of starch digestion and postprandial glucose levels.     

利用淀粉糖化醪进行酒精连续发酵的研究

从多株酒精酵母菌株中筛选出S.cerevisiae KG作为连续发酵菌株,在酒精连续发酵过程中使用具有细胞循环的双罐系统。淀粉经酸酶复合糖化,然后送入酒精连续发酵系统,酒精生产强度可达到28.5(g/l.hr)。     

制麦过程中小麦淀粉含量及淀粉酶活力变化研究

以 6种小麦为试材 ,对制麦前后小麦直链、支链淀粉含量以及发芽过程中的α、β -淀粉酶活力的动态变化进行了研究 ;对成品麦芽中淀粉酶活、淀粉含量及成品麦芽特性之间的关系进行了分析。制麦前后各品种小麦支链、直链淀粉含量均下降 ,总淀粉降解程度与原小麦中支链、直链淀粉比存在正相关性 (P <0 .1)。成品麦芽中α、β -淀粉酶活与品种有关。成品麦芽糖化力与麦芽中淀粉酶活存在显著 (P <0 .0 5 )正相关性 ;成品麦芽糖化时间与麦芽淀粉含量存在极显著 (P <0 .0 1)正相关性。筛选出豫麦 5 0、SP2 0 2 7、pH97194 2为较好的制小麦麦芽品种     

Selected Physicochemical Properties of Starch Isolated from Fermented Sorghum Flour

Starch was isolated from fermented sorghum flour (24 h natural lactic acid fermentation), and water retention, starch solubility, clarity of starch pastes and freeze‐thaw stability were measured. In comparison with starch isolated from unfermented sorghum flour, fermentation increased the solubility of the starch and decreased the water retention, but it had no effect on the freeze‐thaw stability of the starch. There was no substantial difference in the starch paste clarity between the two samples. Storage of starch pastes at lower temperature (4°C) resulted in a very low clarity of starch.