Search

The effects of curdlan gum (CG), konjac gum (KGM), sodium alginate (SA) and xanthan gum (XG) on physicochemical properties, eating quality and digestibility of extruded reconstituted rice were compared in this study. The results showed that reconstituted rice with CG was regular and glossy in appearance, and had lower gelatinization viscosity and digestibility, the lowest short-range order and crystallinity and better retrogradation resistance as well as moderate hardness, non-sticking to teeth and the highest sensory score after cooking. Reconstituted rice with KGM had a smooth surface, the best digestion resistance and moderate retrogradation resistance, gelatinization viscosity not significantly different from that of the control without added hydrophilic colloid, soft texture and the second highest sensory score after cooking. The gelatinization viscosity of reconstituted rice with SA was slightly increased and the digestibility was decreased, but the resistance to retrogradation was moderate and the surface was rough, and the rice was soft and sticky after cooking, with the worst taste. The addition of XG provided reconstituted rice with the highest elasticity and gelatinization viscosity, but reconstituted rice with XG was irregular in appearance, with a rough surface, poor resistance to digestion and retrogradation, and was sticky scored low in sensory evaluation after cooking. In addition, the addition of hydrophilic colloids effectively improved the water stability of reconstituted rice and reduced the cooking loss and water absorption and expansion rate after cooking, and the color of reconstituted rice with hydrophilic colloids was white with a tingle of yellow. The results of this study provide a theoretical reference for the development of high-quality extruded reconstituted rice.

Large-ring cyclodextrin (LR-CD) is a cyclic α-1,4-glucan consisting of nine to several hundred glucopyranose units. LR-CD is mainly prepared by the cyclization activity of cyclodextrin glucosyltransferase or 4-α-glucanotransferase that catalyzes intramolecular transglycosylation reaction on amylose. Compared with common α-, β-, and γ-CD, LR-CD has a larger cavity size and exhibits unique structural and physicochemical properties, showing potential applications in several fields like food, medicine and biology. However, LR-CD has not been industrially produced or applied due to the high cost and low productivity as well as lack of effective separation and purification methods. In this article, recent progress and challenges on the enzymatic preparation of LR-CD are reviewed from the aspects of optimizing reaction substrates, designing new reaction pathways based on template induction, enzyme modification, and separation and purification of products. We hope this article could provide a reference for the industrial production and application of LR-CD.

ObjectiveTo establish a medical imaging teacher competency model and evaluate its application value in group teaching for undergraduates.MethodsBased on literature review, a competency model for teachers in medical colleges and universities was established. This study collected the self-evaluation scores and student evaluation scores of the competency model for teachers from Radiology Department of Peking Union Medical College Hospital who participated in the undergraduate medical imaging group teaching from September 2020 to November 2021, and compared the differences of various competencies before and after training, between different professional titles and between different length of teaching.ResultsA total of 18 teachers were included in the teaching of undergraduate medical imaging group, with 11 having short teaching experience (≤5 years) and 7 having long teaching experience (> 5 years). Altogether 200 undergraduate students participated in the course (95 in the class of 2016 and 105 in the class of 2017). There were 8 teachers with a junior professional title, 5 with an intermediate professional title, and 5 with a senior professional title. The teacher competency model covered a total of 5 first-level indicators, including medical education knowledge, teaching competency, scientific research competency, organizational competency, and others, which corresponded to 13 second-level indicators. The teachers' self-evaluation scores of two first-level indicators, scientific research competency and organizational competency, as well as three second-level indicators, teaching skills, academic research on teaching and research, and communication abilities, showed significant improvements after the training, compared to those before training(all P < 0.05). Compared to the teachers with intermediate to senior professional titles/long teaching years, the teachers with junior professional titles/short teaching years had lower self-evaluation scores for multiple first-level and second-level indicators before the teacher training. After the training, these teachers showed more significant improvements in multiple indicators of self-evaluation scores(all P < 0.05). Additionally, students' evaluation changes for the teachers with junior professional titles before and after the training were consistent with this trend.ConclusionsThe competency model of undergraduate medical imaging teachers based on teacher competency can be preliminarily applied for the training of medical imaging teachers, as it reflects the change of competency of the teachers with different professional titles and teaching years in the process of group teaching.