Final Report Summary - INBODY (Composite Nanoscale Delivery Systems for optimal in body and in product behavior)
• Summary description of the project objectives
Incorporation in foods of compounds that contribute to well-being and health has become object of intensive investigations, in response to increased consumers’ awareness that eating habits should not be merely based on the nutritive properties of food. The issues related to the efficient delivery of bioactive compounds and micronutrients through food matrices, optimizing their bioaccessibility, while minimizing the impact on the qualitative properties of the products, require the development of extremely advanced properties. Moreover, the simultaneous delivery of iron and plant polyphenols, whose consumption is deficient both in developed and in developing countries, is challenged by their high reactivity, with the possible mutual interactions and with other food ingredients likely resulting in undesired reduction of bioavailability and activity, as well as in product quality alteration.
Therefore, novel approaches to the fabrication of delivery systems are desirable, based on the exploitation of the naturally occurring interactions between payload and structural components to enable the control of carrier morphology and functionality, as aids in product protection, digestion rate and bioaccessibility of the payload.
The INBODY project is addressed to the development of zein-based complex delivery systems, whose design is based on the interactions of zein with payload compounds, such as iron and plant polyphenols.
The prolamin zein, the storage protein of corn, is insoluble in water due to the presence of large amount of hydrophobic amino acid residues, and can therefore be applied for the encapsulation of active compounds in high-moisture foods, because of its superior protection ability in comparison to water-soluble polymers. In addition, zein functions as a polymeric amphiphile because of its amino acid composition, offering an exceptional capability of forming complex nanostructures, which can host different types of compounds. Despite the recent studies on the topic, zein delivery systems can be still considered at a pioneering stage, with numerous challenges still remaining, especially concerning the advancement of the knowledge in (a) understanding the colloidal phenomena involving the synthesis of food-grade biopolymeric particles, (b) engineering at the nanoscale structured systems to impart functionalities regulating their in body behaviour, (c) designing simple, cost-effective, easily scalable processes of production of delivery systems with advanced functionality, (d) exploiting the use of zein for food applications.
The INBODY project has been focused on developing zein-based colloidal delivery systems, characterized by a core-shell architecture, where the core is formed through spontaneous molecular interactions between zein and iron and/or polyphenols, for controlled release and better preservation of the payload, whereas the external stabilization layer is formed through the deposition of absorbed biopolymers, e.g. polyelectrolytes, to improve biocompatibility, bioaccessibility and functionality.
• Description of the work performed since the beginning of the project
The research activities carried out during the 1 year of project duration have been projected towards novel possibilities of exploitation of zein-based colloidal systems, with specific reference to the following fields (not necessarily listed in chronological order):
(a) Delivery of water soluble polyphenols, such as epigallocatechin gallate, controlling their release and activity during digestion
(b) Development of facile and versatile methods for extraction and encapsulation of bioactive molecules from plant products for the food industry
(c) Optimization of the production of zein colloidal particles to encapsulate phenolic compounds
(d) Delivery of soluble forms of Fe(III)
(e) Development of composite colloidal particles, based on the combination of zein and ethylcellulose, to encapsulate different payload compounds, such as soluble Fe(III), curcumin or epigallocatechin gallate.
Despite the challenged topics need more than one year of research to full development and understanding, the achieved results show, in a wide range of applications, the potentiality and flexibility of zein-based particles, especially as carrier systems for a wide variety of payload compounds.
• Description of the main results achieved so far
The main scientific results obtained by INBODY project are listed in the following:
(a) Zein-based particles to encapsulated epigallocatechin gallate (EGCG): Encapsulation of water-soluble compounds, such as EGCG, in zein particles, differently from water-insoluble compounds, is limited by the weak physical interactions occurring during the precipitation phase. Chemical interactions with additional biopolymers, such as sodium caseinate (NaCas) has been exploited to improve the encapsulation efficiency by forming structured core-shell particles. Zein particles coated with a NaCas layer were able to increase the encapsulation efficiency of EGCG with respect to uncoated Zein particles. Remarkably, the higher amount of EGCG encapsulated appears to be mainly localized on the particle outer layer, where it is bioaccessible and can express its antioxidant activity. Such structured particles exhibit an interesting behavior especially during digestion, with NaCas being more easily digestible than zein alone. In addition, the encapsulation of EGCG into zein particles resulted into a promising additive to modulate the rate of fat digestion.
(b) Facile and versatile methods for extraction and encapsulation in zein colloidal particles of bioactive molecules from plant products: A facile and versatile method was based on the extraction of natural bioactive compounds using the same ethanol-water binary solvent used to dissolve zein, exploiting the spontaneous molecular interactions of zein with hydrophobic compounds. The control of precipitation conditions of these systems into colloidal dispersions enabled to tune particle stability and encapsulation efficiency. Moreover, by selection of the natural extracts, also other interesting properties of these colloidal dispersions can be developed, and in particular the light absorption and the antioxidant activity.
(c) Optimization of the production of zein colloidal particles to encapsulate different phenolic compounds: This work contributed to define the optimal conditions of antisolvent precipitation of zein particles, suggesting that significant undesired effects might occur when the particle synthesis is not carried out under controlled conditions, in terms of particle size distribution and antioxidant activity of the particles. This was shown by testing 5 different bioactive molecules (naringening, thymol, eugenol, limonene, tannic acid), with different affinity for the water phase, and comparing different biopolymers for the external shell layer.
(d) Zein-based particles to encapsulated soluble Fe(III): The chemistry of soluble iron and zein is fascinating and complex. Bioinspired systems, which mimic iron storage proteins such as ferritin, were developed, based on zein colloidal particles, where molecular interactions between zein and Fe(III) enable an extremely fine control of particle size, as well as high encapsulation efficiency. However, experimental observations suggested that most of the iron is located on the particle surface and can easily interact with the external environment (i.e. ferrozine or other co-encapsulated phenolic compounds, such as curcumin).
(e) Composite colloidal particles, based on zein and ethylcellulose to encapsulate Fe(III), curcumin or EGCG: EC+Zein composite particles enable to tailor the encapsulation of a wide variety of payload compounds, ranging from Fe(III) to curcumin and EGCG. With respect to plain zein particles, the use of EC causes the formation of a structure, where either iron or curcumin can be more efficiently encapsulated, with consequences on the reactivity and antioxidant activity of the compounds. In the case of EGCG, whose hydrophilicity limits the efficiency of physical entrapment during antisolvent precipitation, the encapsulation in composite particles enable the use of EGCG as additive to modulate fat digestion.
• Expected final results and their potential impact and use (including the socio-economic impact and the wider societal implications of the project so far)
The exploitation of zein-based colloidal particles as delivery systems for bioactives or minerals in food products is at its infancy, with numerous challenges still remaining. INBODY project focused both on the advancement of the knowledge on the driving forces towards the synthesis of zein-based colloidal particles, and on the definition of the process conditions to obtain desired particle architecture, morphology and in product and in body behaviour.
The expected final result of the INBODY project is hence to provide an extensive study on the spontaneous molecular interactions between zein and polyphenols and/or iron, as novel bio-inspired approach to the synthesis of complex biopolymeric carrier particles, suitable for food applications. The fundamental understanding of the principles of assembly of zein-based particles developed by INBODY has been projected into a better command of the processes of fabrication of the desired particle architecture, as well as of control of their functionality, especially for what concerns the bioaccessibility, release and bioactivity of the payload compounds.
These are crucial aspects of a wider use of zein-based carriers in food functionalization and fortification, which have led INBODY also towards the exploration of different applicative case studies. For example, the encapsulation of different minerals and plant polyphenols into complex colloidal particles has been investigated in terms of the resulting bioactivity during simulated in product or in body use.
Besides the contribution to scientific research and industrial application, with important socio-economic implications, the results of INBODY are likely also to led to a wider societal impact. As already stated, both iron and plant polyphenols are characterized by a deficient consumption both in developed and in developing countries, and therefore, technological solutions, which enable the incorporation of these compounds into food products, through the use of food compatible carriers, has the potential to fill up this deficiency in the more sensitive sub-populations.
Incorporation in foods of compounds that contribute to well-being and health has become object of intensive investigations, in response to increased consumers’ awareness that eating habits should not be merely based on the nutritive properties of food. The issues related to the efficient delivery of bioactive compounds and micronutrients through food matrices, optimizing their bioaccessibility, while minimizing the impact on the qualitative properties of the products, require the development of extremely advanced properties. Moreover, the simultaneous delivery of iron and plant polyphenols, whose consumption is deficient both in developed and in developing countries, is challenged by their high reactivity, with the possible mutual interactions and with other food ingredients likely resulting in undesired reduction of bioavailability and activity, as well as in product quality alteration.
Therefore, novel approaches to the fabrication of delivery systems are desirable, based on the exploitation of the naturally occurring interactions between payload and structural components to enable the control of carrier morphology and functionality, as aids in product protection, digestion rate and bioaccessibility of the payload.
The INBODY project is addressed to the development of zein-based complex delivery systems, whose design is based on the interactions of zein with payload compounds, such as iron and plant polyphenols.
The prolamin zein, the storage protein of corn, is insoluble in water due to the presence of large amount of hydrophobic amino acid residues, and can therefore be applied for the encapsulation of active compounds in high-moisture foods, because of its superior protection ability in comparison to water-soluble polymers. In addition, zein functions as a polymeric amphiphile because of its amino acid composition, offering an exceptional capability of forming complex nanostructures, which can host different types of compounds. Despite the recent studies on the topic, zein delivery systems can be still considered at a pioneering stage, with numerous challenges still remaining, especially concerning the advancement of the knowledge in (a) understanding the colloidal phenomena involving the synthesis of food-grade biopolymeric particles, (b) engineering at the nanoscale structured systems to impart functionalities regulating their in body behaviour, (c) designing simple, cost-effective, easily scalable processes of production of delivery systems with advanced functionality, (d) exploiting the use of zein for food applications.
The INBODY project has been focused on developing zein-based colloidal delivery systems, characterized by a core-shell architecture, where the core is formed through spontaneous molecular interactions between zein and iron and/or polyphenols, for controlled release and better preservation of the payload, whereas the external stabilization layer is formed through the deposition of absorbed biopolymers, e.g. polyelectrolytes, to improve biocompatibility, bioaccessibility and functionality.
• Description of the work performed since the beginning of the project
The research activities carried out during the 1 year of project duration have been projected towards novel possibilities of exploitation of zein-based colloidal systems, with specific reference to the following fields (not necessarily listed in chronological order):
(a) Delivery of water soluble polyphenols, such as epigallocatechin gallate, controlling their release and activity during digestion
(b) Development of facile and versatile methods for extraction and encapsulation of bioactive molecules from plant products for the food industry
(c) Optimization of the production of zein colloidal particles to encapsulate phenolic compounds
(d) Delivery of soluble forms of Fe(III)
(e) Development of composite colloidal particles, based on the combination of zein and ethylcellulose, to encapsulate different payload compounds, such as soluble Fe(III), curcumin or epigallocatechin gallate.
Despite the challenged topics need more than one year of research to full development and understanding, the achieved results show, in a wide range of applications, the potentiality and flexibility of zein-based particles, especially as carrier systems for a wide variety of payload compounds.
• Description of the main results achieved so far
The main scientific results obtained by INBODY project are listed in the following:
(a) Zein-based particles to encapsulated epigallocatechin gallate (EGCG): Encapsulation of water-soluble compounds, such as EGCG, in zein particles, differently from water-insoluble compounds, is limited by the weak physical interactions occurring during the precipitation phase. Chemical interactions with additional biopolymers, such as sodium caseinate (NaCas) has been exploited to improve the encapsulation efficiency by forming structured core-shell particles. Zein particles coated with a NaCas layer were able to increase the encapsulation efficiency of EGCG with respect to uncoated Zein particles. Remarkably, the higher amount of EGCG encapsulated appears to be mainly localized on the particle outer layer, where it is bioaccessible and can express its antioxidant activity. Such structured particles exhibit an interesting behavior especially during digestion, with NaCas being more easily digestible than zein alone. In addition, the encapsulation of EGCG into zein particles resulted into a promising additive to modulate the rate of fat digestion.
(b) Facile and versatile methods for extraction and encapsulation in zein colloidal particles of bioactive molecules from plant products: A facile and versatile method was based on the extraction of natural bioactive compounds using the same ethanol-water binary solvent used to dissolve zein, exploiting the spontaneous molecular interactions of zein with hydrophobic compounds. The control of precipitation conditions of these systems into colloidal dispersions enabled to tune particle stability and encapsulation efficiency. Moreover, by selection of the natural extracts, also other interesting properties of these colloidal dispersions can be developed, and in particular the light absorption and the antioxidant activity.
(c) Optimization of the production of zein colloidal particles to encapsulate different phenolic compounds: This work contributed to define the optimal conditions of antisolvent precipitation of zein particles, suggesting that significant undesired effects might occur when the particle synthesis is not carried out under controlled conditions, in terms of particle size distribution and antioxidant activity of the particles. This was shown by testing 5 different bioactive molecules (naringening, thymol, eugenol, limonene, tannic acid), with different affinity for the water phase, and comparing different biopolymers for the external shell layer.
(d) Zein-based particles to encapsulated soluble Fe(III): The chemistry of soluble iron and zein is fascinating and complex. Bioinspired systems, which mimic iron storage proteins such as ferritin, were developed, based on zein colloidal particles, where molecular interactions between zein and Fe(III) enable an extremely fine control of particle size, as well as high encapsulation efficiency. However, experimental observations suggested that most of the iron is located on the particle surface and can easily interact with the external environment (i.e. ferrozine or other co-encapsulated phenolic compounds, such as curcumin).
(e) Composite colloidal particles, based on zein and ethylcellulose to encapsulate Fe(III), curcumin or EGCG: EC+Zein composite particles enable to tailor the encapsulation of a wide variety of payload compounds, ranging from Fe(III) to curcumin and EGCG. With respect to plain zein particles, the use of EC causes the formation of a structure, where either iron or curcumin can be more efficiently encapsulated, with consequences on the reactivity and antioxidant activity of the compounds. In the case of EGCG, whose hydrophilicity limits the efficiency of physical entrapment during antisolvent precipitation, the encapsulation in composite particles enable the use of EGCG as additive to modulate fat digestion.
• Expected final results and their potential impact and use (including the socio-economic impact and the wider societal implications of the project so far)
The exploitation of zein-based colloidal particles as delivery systems for bioactives or minerals in food products is at its infancy, with numerous challenges still remaining. INBODY project focused both on the advancement of the knowledge on the driving forces towards the synthesis of zein-based colloidal particles, and on the definition of the process conditions to obtain desired particle architecture, morphology and in product and in body behaviour.
The expected final result of the INBODY project is hence to provide an extensive study on the spontaneous molecular interactions between zein and polyphenols and/or iron, as novel bio-inspired approach to the synthesis of complex biopolymeric carrier particles, suitable for food applications. The fundamental understanding of the principles of assembly of zein-based particles developed by INBODY has been projected into a better command of the processes of fabrication of the desired particle architecture, as well as of control of their functionality, especially for what concerns the bioaccessibility, release and bioactivity of the payload compounds.
These are crucial aspects of a wider use of zein-based carriers in food functionalization and fortification, which have led INBODY also towards the exploration of different applicative case studies. For example, the encapsulation of different minerals and plant polyphenols into complex colloidal particles has been investigated in terms of the resulting bioactivity during simulated in product or in body use.
Besides the contribution to scientific research and industrial application, with important socio-economic implications, the results of INBODY are likely also to led to a wider societal impact. As already stated, both iron and plant polyphenols are characterized by a deficient consumption both in developed and in developing countries, and therefore, technological solutions, which enable the incorporation of these compounds into food products, through the use of food compatible carriers, has the potential to fill up this deficiency in the more sensitive sub-populations.