Preparation and release properties of flufiprole-loaded microcapsules with core status of solid particles, solution droplets and oil suspending agent

The Film-Forming Characterization and Structural Analysis of Pectin from Sunflower Heads

A natural low-methoxyl pectin (termed AHP, $\text{DM}=25.9\%$ ) was extracted from dried heads of sunflower and showed better film-forming performance blended with hydroxypropyl methylcellulose (HPMC). The solutions and films of different HPMC/AHP blends were characterized by viscosity, transparency, mechanical properties, loss on drying, water drop penetration time (WDPT), disintegration and SEM. In order to analyze the structure-property relationship of film forming, AHP was separated by ion-exchange chromatography and characterized. The results showed that the blends were immiscible, but the formation of AHP gel would give the blended film better mechanical properties. AHP was fractionated into one neutral fraction and two acidic fractions (AHPA-1 and AHPA-2). The analytical results showed that AHPA-1 and AHPA-2 were identified to be homogalacturonan- (HG-) rich pectins with low DM, and the molecular weights of them were estimated to be 106 kDa and 226 kDa, respectively. Due to the high content of the HG domain, low DM and high molecular weights, AHP had excellent gelling properties induced by Ca2+ and was added to improve the film-forming properties of HPMC and to develop plant hollow capsules.

A Novel Shell Material-Highland Barley Starch for Microencapsulation of Cinnamon Essential Oil with Different Preparation Methods

Highland barley starch (HBS), as a carbohydrate shell material with excellent performance in microcapsule applications, has rarely been reported. In the present study, three different microcapsules (CEO-SWSM, CEO-PM, and CEO-UM) were synthesized successfully via saturated aqueous solution method, molecular inclusion method and ultrasonic method, respectively, using HBS as shell material coupled with cinnamon essential oil (CEO) as the core material. The potential of HBS as a new shell material and the influence of synthetic methods on the performance of microcapsules, encapsulation efficiency (EE), yield, and release rate of CEO-SWSM, CEO-PM, and CEO-UM were determined, respectively. The results confirmed that CEO-PM had the most excellent EE (88.2%), yield (79.1%), as well as lowest release rate (11.5%, after 25 days of storage). Moreover, different kinetic models were applied to fit the release process of these three kinds of microcapsules: CEO-SWSM, CEO-PM, and CEO-UM had the uppermost R-squared value in the Higuchi model, the zero-order model, and the first-level model, respectively. Over all, this work put forward a novel perspective for the improved encapsulation effect of perishable core materials (e.g., essential oil) for the food industry.