Physicochemical properties and in vitro digestibility of pulse starches and derivatized type 3 resistant starch

The objective of this thesis was to isolate and characterize pea, lentil and faba bean starches from air-classified flours and to develop a novel type 3 resistant starch (RS3) from the isolated pulse starches. In the pulse processing industry in Canada, the majority of pulse starches are generated in the form of starch-rich flours from air classification. The first study aimed to isolate starches of a high purity from the most common starch-rich pulse flours (i.e., pea, lentil and faba bean) and to determine and compare the molecular structure, functional properties and in vitro digestibility of the isolated pulse starches with those of four important commercial starches (i.e., Roquette pea, normal maize, waxy maize and tapioca). The isolated pulse starches showed amylose contents and amylopectin branch-chain-length (BCL) distributions similar to that of Roquette pea starch. Consequently, the granular morphologies, crystalline structure, thermal properties, pasting properties, gelling ability and in vitro digestibility of the isolated pulse starches were comparable to those of Roquette pea starch but were distinctively different from those of commercial maize and tapioca starches. Because the isolated pea, lentil and faba bean starches exhibited similar amylose contents and comparable amylopectin BLC distributions, the isolated pea starch was selected as the representative pulse starch to develop a novel RS3 product through acid thinning, debranching and recrystallization in the second study, with commercial normal maize starch being included for comparison. Starting from the respective native starches, the modification method yielded 68.1% of RS3 from pea and 59.6% from normal maize. In vitro starch digestibility assay revealed that pea RS3 (in both uncooked and cooked states) was less digestible to amylolytic enzymes than normal maize RS3. The results obtained could be ascribed to the formation of thermally more stable double-helical crystallites in the former, which consisted of a larger proportion of intermediate chains and a smaller proportion of short chains when compared with normal maize RS3. This study indicated that the developed modification method was effective to increase the enzymatic resistance of pulse starch, which could be employed to prepare lowglycemic food ingredients and expand new markets for the underutilized co-product

Aligned Graphene Nanoribbons and Crossbars from Unzipped Carbon Nanotubes

Aligned graphene nanoribbon (GNR) arrays were made by unzipping of aligned single-walled and few-walled carbon nanotube (CNT) arrays. Nanotube unzipping was achieved by a polymer-protected Ar plasma etching method, and the resulting nanoribbon array was transferred onto any substrates. Atomic force microscope (AFM) imaging and Raman mapping on the same CNTs before and after unzipping confirmed that ~80% of CNTs were opened up to form single layer sub-10 nm GNRs. Electrical devices made from the GNRs (after annealing in H2 at high temperature) showed on/off current (Ion/Ioff) ratios up to 103 at room temperature, suggesting semiconducting nature of the narrow GNRs. Novel GNR-GNR and GNR-CNT crossbars were fabricated by transferring GNR arrays across GNR and CNT arrays, respectively. The production of ordered graphene nanoribbon architectures may allow for large scale integration of GNRs into nanoelectronics or optoelectronics.Comment: published in Nano Researc

Main Problems in College Students’ Oral English Learning and the Corresponding Teaching Strategies

For a long time, college English learners attach more attention to the input of language knowledge while ignoring the output aspect in language practice, leading to the dissatisfactory phenomena—“dumb English”. This paper aims at the main problems in college students’ oral English learning and points out several prominent problems such as the internalized factors in language knowledge; meanwhile, it presents some effective strategies in English teaching such as the combination of “modeling and imitating” strategy, presenting strategy, situation creating strategy with detailed examples

Does sustainable financial inclusion and energy efficiency ensure green environment? Evidence from B.R.I.C.S. countries

Continuous rise in a global economy with a 3–4% annual growth rate poses a severe risk to environmental sustainability due to high energy demand. Since the Paris climate accord, countries worldwide have implemented numerous strategies to attain the target of carbon neutrality. With the rising environmental challenges, it is important to consider global financial inclusion (F.I.) policies. This study uses panel data for the B.R.I.C.S. countries to investigate the impact of F.I. and energy efficiency in limiting trade adjusted emissions (T.A.E.) taking technological innovation and trade as control variables. This study uses panel data consisting small sample size and large time period; therefore, keeping in mind the potential econometric problems, this study uses AMG method, which can efficiently deal with endogeneity problems and small sample bias. We find a positive impact of F.I. and energy efficiency on CO2 emissions. Moreover, we find that technological innovation, exports and output amplify CO2 emissions