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71.
淀粉/聚乙烯醇全降解缓释塑料薄膜的制备与性能研究 总被引:3,自引:0,他引:3
聚乙烯醇(PVA)溶解后与淀粉(St)共混,同时加入增塑剂丙三醇、交联剂甲醛,反应结束后将包膜液流延成膜。考察了m(St)∶m(PVA)、反应温度、丙三醇用量、甲醛加入方式、甲醛用量、反应时间对薄膜性能的影响,并表征了薄膜的结构。结果表明:当m((St)∶m(PVA)=7∶3、反应温度为90℃、w(丙三醇)=3%(占St、PVA、纯水质量之和的质量分数)、甲醛一次性加入、w(甲醛)=2%、反应时间为1 h时,制得的塑料薄膜拉伸强度、断裂伸长率较大,吸水率和透NH4+率均较低,共混体系的相容性好。 相似文献
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R. Rendón-Villalobos E. Agama-AcevedoJ.J. Islas-Hernández J. Sánchez-MuñozL.A. Bello-Pérez 《Food chemistry》2006
Tortillas were prepared using commercial hydrocolloids, stored for 7 and 14 days and their available, resistant and retrograded resistant starches, were evaluated alongside their in vitro starch digestibility. Available starch (AS) decreased with storage time and tortillas with hydrocolloids had lower values than the control sample. Tortillas elaborated with TC-20 gum did not present substantial differences in AS. Control tortilla had resistant starch (RS) content that increased with storage time but, in general, tortillas with hydrocolloids did not show any change in RS values with storage time, except tortillas with TC-1 gum that presented a slight increase after 7 storage days. Approximately 50% of RS is due to the retrogradation phenomenon as it was shown by the amount of retrograded resistant starch (RRS). Tortillas with added hydrocolloids had lower hydrolysis percentage and the hydrolysis was slower than in the control. In general, tortillas prepared with hydrocolloids had a lower tendency for retrogradation than control tortillas; it is important to consider this to obtain tortillas with better texture and lower RS content. 相似文献
74.
Trevor S Rasmussen Robert J Henry 《Journal of the science of food and agriculture》1990,52(2):159-170
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. 相似文献
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The degree of gelatinisation and electrical conductivity of wheat starch and tapioca starch suspensions (5% w/w) were determined after a pressure treatment of up to 530 MPa. With increasing pressure at a constant treatment time the degree of gelatinisation increased resulting in a gelatinisation curve similar to that of thermal gelatinisation. A pressure increase also caused an increase in electrical conductivity. A good linear relationship between the degree of gelatinisation and the electrical conductivity for both starches investigated was found. Since electrical conductivity correlates well with the degree of gelatinisation of starches after pressure treatment it is applicable for the quick and simple determination of pressure-induced starch gelatinisation. 相似文献
77.
为探讨湖南湘西食用百合(BJBH)的品质特性,本试验系统分析其主要营养成分,生、熟百合质构特性,全粉与精制淀粉的膨胀势和凝胶质构及淀粉理化特性。结果表明:在研究变幅内,BJBH的蛋白、淀粉及膳食纤维等主要成分含量表示出不同;煮熟后其质构特性变化主要是由大分子物质(淀粉、膳食纤维)吸水膨胀引起;全粉和淀粉膨胀势分别为6.2和14.5 g/g,纤维素等不溶性多糖是导致两者凝胶质构显著不同的主要因素;BJBH淀粉颗粒粒径集中分布在9.09~34.57μm,平均粒径19.28μm;衍射类型属B型,相对结晶度为54.4%;DSC曲线中TO、TP、TC和ΔHgel分别为54.0、63.2、75.0℃和13.3 J/g;淀粉颗粒酶解速率先快后慢,72 h后分解速率趋于稳定;淀粉颗粒的吸水速率先减慢后升快,在相对湿度为100%时吸水量约为215 mg/g。 相似文献
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80.
Anthony M. C. Davies David T. Coxon Gillian M. Gavrel David J. Wright 《Journal of the science of food and agriculture》1985,36(1):49-54
Equations were derived for predicting starch and lipid content of pea varieties from near infrared data measured on a filter instrument (Technicon InfraAlyzer 400). The accuracy of the predictions were tested against separate data sets and were found to be better than ±2.6% for starch (range 20–45%) and ±0.3% for lipid (range 1.4–3.3%). Together with the previous work on the near infrared determination of protein it is possible to analyse rapidly for three components important to a plant breeding programme. The study has also demonstrated a clear-cut delineation between round and wrinkled pea genotypes. 相似文献