Microcapsule production employing chickpea or lentil protein isolates and maltodextrin: Physicochemical properties and oxidative protection of encapsulated flaxseed oil
Microcapsule production employing chickpea or lentil protein isolates and maltodextrin: Physicochemical properties and oxidative protection of encapsulated flaxseed oil
Year: 2013
Authors: Karaca, A.C. Nickerson, M. Low, N.H.
Publication Name: Food Chem.
Publication Details: Volume 139; Pages 448-457; dx.doi.org/10.1021/jf400787j |
Abstract:
Flaxseed oil was microencapsulated, employing a wall material matrix of either chickpea (CPI) or lentil protein isolate (LPI) and maltodextrin, followed by freeze-drying. Effects of oil concentration (5.3 to 21.0percent), protein source (CPI vs. LPI) and maltodextrin type (DE 9 and 18) and concentration (25.0 to 40.7percent), on both the physicochemical characteristics and microstructure of the microcapsules, were investigated. It was found that an increase in emulsion oil concentration resulted in a concomitant increase in oil droplet diameter and microcapsule surface oil content, and a decrease in oil encapsulation efficiency. Optimum flaxseed oil encapsulation efficiency (83.5percent), minimum surface oil content (2.8percent) and acceptable mean droplet diameter (3.0 lm) were afforded with 35.5percent maltodextrinDE 9 and 10.5percent oil. Microcapsules, formed by employing these experimental conditions, showed a protective effect against oxidation versus free oil over a storage period of 25 d at room temperature. (Authors abstract)
Microencapsulation is defined as a process whereby an active ingredient becomes enclosed or packaged within micron-sized carrier matrices, which in turn segregate and protect the inner core from the surrounding environment . Although gelatin is one of the most widely used encapsulating materials, it suffers from a number of perceived safety concerns (e.g., prion disease), and religious and dietary restrictions. Therefore, the development of plant protein based encapsulation systems, as an alternative to animal proteins, is of considerable interest and importance. Legume proteins can serve as a potential source for this purpose because of their high nutritional value, low cost and purported beneficial health benefits, including, but not limited to, reducing the risk of cardiovascular disease, as an aid in glycemic control in diabetic individuals, and in the prevention of digestive tract diseases. The objectives of this study were to study flaxseed oil microencapsulation potential of chickpea (CPI) and lentil protein isolates (LPI) and maltodextrin, as wall materials, and to investigate the physicochemical properties, surface microstructure, and flaxseed oil oxidative protection of the produced microcapsules.
Overall, higher flaxseed oil encapsulation efficiencies coupled with lower surface oil contents were achieved in CPI and LPI based microcapsules containing maltodextrin DE 9. Experimental results also show that flaxseed oil encapsulation efficiencies in CPI and LPI maltodextrin systems were dependent upon multiple factors. When comparing microcapsule formation at pH 7.0; LPI based materials had a lower moisture content and darker colour than had CPI based ones, and no significant difference was observed in surface oil content and encapsulation efficiency between these protein isolates. Water redispersion of the freeze dried microcapsules resulted in an increase in droplet diameter for CPI-based materials while droplet diameter remained unchanged in LPI based ones. Experimental results showed that CPI and LPI based microcapsule formation was efficient for the entrapment and gastrointestinal delivery of flaxseed oil. Microcapsules, prepared by employing these two plant proteins in conjunction with maltodextrin, exhibited a protective effect against oxidation over a 25 d storage period at room temperature, as indicated by a lack of significant change in initial PV and TBARS results. The optimum microcapsule formulation of those studied included CPI or LPI, maltodextrin DE 9 and 10.5percent flaxseed oil, followed by freeze-drying. These microcapsules had a low surface flaxseed oil content (<3percent), a high flaxseed oil encapsulation efficiency (83percent), and showed high (>84percent) release properties under simulated gastrointestinal conditions. These findings suggest that the developed plant-based microencapsulation system could lead to increased utilisation of flaxseed oil and legume proteins in food and bioproduct formulations and applications. (Editors comments)
