A kinetic study of the release of vanillin encapsulated in Carnauba wax microcapsules

Bio-based clothianidin-loaded solid dispersion using composite carriers to improve efficacy and reduce environmental toxicity

BACKGROUND

Neonicotinoids comprise one of the most extensively used classes of pesticides worldwide owing to their broad insecticidal spectrum and excellent biological performance. However, their toxicity to honeybee (Apis mellifera Linnaeus) and silkworm (Bombyx Mori) limits their further application. To address this issue, clothianidin as a model neonicotinoid was developed into a novel controlled-release formulation employing advantaged solid dispersion (SD) technology using composite carriers.

RESULTS

In this research, the clothianidin-loaded SD was characterized using integrated methods to elucidate its formation mechanism, showing that clothianidin was embedded into the carrier homogeneously in small crystalline entities. The composite carriers, which are both renewable and environmentally friendly, can significantly prolong the release of clothianidin from seven to 25 days, compared with that of PEG 8000 as a single carrier. Based on the excellent controlled release profiles, it reduced the acute toxicity to A. mellifera and B. mori by 57.68- and 85.32-fold (respectively) compared with that of the conventional formulation. Furthermore, the SD displayed favorable efficacy and persistency against Asian citrus psyllid (Hemiptera: Psyllidae).

CONCLUSION

This novel strategy opens up a simple and powerful avenue for improving efficacy and promoting the environmental safety of neonicotinoid insecticides to be used in sustainable crop protection.

Polyolefin Wax Modification Improved Characteristics of Nutrient Release from Biopolymer-Coated Phosphorus Fertilizers

Coating fertilizer is an effective approach to increase the fertilizer use efficiency and reduce fertilizer application rate. However, only a few studies have focused on coating phosphorus (P) fertilizer, especially diammonium phosphate (DAP) due to its irregular shape and high specific surface area. A novel and low-cost strategy centered on wax-based surface modification and bio-based polymer coating was applied to improve the nutrient characteristics of coated DAP (CDAP). Regular DAP was modified with polyolefin wax and then coated with polyurethanes prepared from castor oil. Experimental results indicated that wax modification significantly decreased the specific surface area, angle of repose of DAP particles, increased the particle hardness, and then facilitated the formation of biopolymer-based coating. The CDAP from wax-modified DAP had better controlled-release performance compared with that from normal DAP. Findings from this study indicate that wax modification can be used as an effective technology to prepare highly efficient controlled-release P fertilizers.

Carnauba wax as a wall material for urea microencapsulation

BACKGROUND

The high ureolytic activity of rumen microbiota is a concern when urea is used in ruminant feed, because it leads to fast urea conversion, resulting in possible intoxication and lower nitrogen utilization. This study intended to microencapsulate urea using carnauba wax to obtain slow-release systems in the rumen. The experiment was conducted in a randomized block design, arranged in a 3 × 2 factorial, with the urea encapsulated with carnauba wax in ratios of 1 : 2; 1 : 3, and 1 : 4 (U_ME 2; U_ME 3, and U_ME 4) and two particles sizes (small, P_S ; and large, P_L ).

RESULTS

All formulations showed excellent properties, including inhibition of urea hygroscopicity. The formulation U_ME 2 exhibited the greatest yield (91.6%) and microencapsulation efficiency (99.6%) values, whereas the formulation U_ME 4 presented the greatest thermal stability (259.5 °C) and lowest moisture content (1.81%). The U_ME 2 formulation presented a slower release than the other U_ME formulations studied.

CONCLUSION

The production of urea microspheres using carnauba wax was successful for all microencapsulated systems developed, evidencing the promising potential for use in ruminant animal diets. The U_ME 2 formulation with large particles is the most recommended because it permitted greater resistance to microbial attack, allowing a slower release of urea into the rumen, reducing the risk of intoxication or ruminal alkalosis. © 2018 Society of Chemical Industry.

Fabrication of electrospun almond gum/PVA nanofibers as a thermostable delivery system for vanillin

In this study, the fabrication of vanillin incorporated almond gum/polyvinyl alcohol (PVA) nanofibers through electrospinning has been investigated. Electrospinning of only almond gum was proved impossible. It was found that the aqueous solution of almond gum/PVA (80:20, concentration=7% (w/w)) containing 3% (w/w) vanillin could have successfully electrospun to uniform nanofibers with diameters as low as 77nm. According to the thermal analysis, incorporated vanillin in almond gum/PVA nanofibers showed higher thermal stability than free vanillin, making this composite especially suitable for high temperature applications. XRD and FTIR analyses proved the presence of vanillin in the almond gum/PVA nanofibers. It was also found that vanillin was dispersed as big crystallites in the matrix of almond gum/PVA nanofibers. FTIR analysis showed almond gum and PVA had chemical cross-linking by etheric bonds between COH groups of almond gum and OH groups of PVA. Also, in the nanofibers, there were no major interaction between vanillin and either almond gum or PVA.

Effect of whey protein isolate and β-cyclodextrin wall systems on stability of microencapsulated vanillin by spray-freeze drying method

Vanillin flavour is highly volatile in nature and due to that application in food incorporation is limited; hence microencapsulation of vanillin is an ideal technique to increase its stability and functionality. In this study, vanillin was microencapsulated for the first time by non-thermal spray-freeze-drying (SFD) technique and its stability was compared with other conventional techniques such as spray drying (SD) and freeze-drying (FD). Different wall materials like β-cyclodextrin (β-cyd), whey protein isolate (WPI) and combinations of these wall materials (β-cyd + WPI) were used to encapsulate vanillin. SFD microencapsulated vanillin with WPI showed spherical shape with numerous fine pores on the surface, which in turn exhibited good rehydration ability. On the other hand, SD powder depicted spherical shape without pores and FD encapsulated powder yielded larger particle sizes with flaky structure. FTIR analysis confirmed that there was no interaction between vanillin and wall materials. Moreover, spray-freeze-dried vanillin + WPI sample exhibited better thermal stability than spray dried and freeze-dried microencapsulated samples.