With the future rise in diabetic

With the future rise in diabetic population worldwide, the search foractive compounds with α-glucosidase inhibitory activity from medicinal plants has become a very meaningful task. Furthermore, these compounds can be evaluated for potential pharmacological activity against other metabolic diseases.
Conflict of interest
Introduction Hepatopancreas, a byproduct generated from the manufacturing of hepatopancreas-free whole shrimp, has been reported to contain high content of n-3 PUFA and astaxanthin [1]. However, n-3 PUFA are easily oxidized due to their high degree of unsaturation. As a consequence, off-flavour compounds [2] as well as toxic products [3] are formed. To lower such a deterioration, encapsulation can be as a key technology in delaying or inhibiting oxidation and masking undesirable odours and flavours in the final product [4]. Furthermore, the process converts the oil into a free flowing powder, which can be easily handled and used for nutraceuticals and/or food fortification. Micro-encapsulation can be defined as a process, in which tiny droplets, namely core, are surrounded by a coating of micro-encapsulating agent. This coating wall can be made of a variety of food grade materials and can protect the entrapped core by providing a physical barrier against environmental conditions [5]. Protein is widely used in the preparation of emulsion and serves as coating wall material during micro-encapsulation process. In recent years, the interest in milk proteins as encapsulating agents has increased and the concept of using milk products as wall materials has been established [6]. The wall material must have emulsifying properties and be capable of dehydration. The milk protein products including sodium caseinate and whey protein concentrate have excellent emulsifying and dehydration properties [7]. Whey protein and sodium caseinate act as the emulsifier, which can stabilize the emulsion before drying [8]. Additionally, emulsification is one of the critical steps in micro-encapsulation of trk receptor by spray-drying, as the emulsion stability and droplet size play a key role in the encapsulation efficiency during and after the process [9]. To ensure the uniform distribution of oil droplet, homogenization with sufficient pressure for emulsification has been widely used in emulsion preparation and encapsulation in the food industry [10,11]. The advantage of high pressure homogenization over other technologies is that strong shear and cavitation forces efficiently decrease the diameter of the original droplets [12]. High pressure homogenization induces significant changes in the interfacial protein layer because of the considerable increase in interaction between adsorbed proteins at the interface of the emulsion [13]. Several factors such as process conditions, protein concentration and oil volume fraction have been reported to affect the properties of emulsion [14]. Spray-drying is the most common micro-encapsulation technology used in food industry due to its low cost and available equipment [15]. The process involves the atomization of emulsions into a drying medium at a high temperature, resulting in very fast water evaporation. The micro-encapsulated oil was reported to have higher oxidation stability during the extended storage [16]. Although the micro-encapsulation of several oils or lipids has been reported, no information regarding the micro-encapsulation of shrimp oil has been reported. Due to the differences in composition of oils from different sources, emulsification conditions prior to spray drying can be varied and determine the characteristics of the obtained powder. Thus, this study aimed to investigate the impact of homogenization at varying pressure levels and the ratio of core/wall material on characteristics of encapsulated shrimp oil.
Materials and methods
Results and discussion
Conclusion Shrimp oil was encapsulated from emulsion stabilized by whey protein concentrate and sodium caseinate (1:1, w/w). Core/wall material ratio and homogenizing pressure directly had the impact on emulsion and resulting encapsulated powder. Higher homogenizing pressure reduced droplet size of emulsion. Emulsification at 27.58MPa with a core/wall material ratio of 1:4 yielded the emulsion with the highest stability during 14 days of storage. After spray drying, emulsion with high core/wall material ratio and homogenizing pressure rendered the micro-encapsulated shrimp oil powder with higher EE. Thus, shrimp oil could be encapsulated using a mixture of whey protein concentrate and sodium caseinate (1:1, w/w) as encapsulating agents with core/wall material ratio of 1:4 and homogenizing pressure level of 27.58MPa, followed by spray-drying. However, the conditions used in the present study still showed the low encapsulation efficiency, the improvement of encapsulation process for shrimp oil is still required.