Periodic Reporting for period 1 - FamousSPNP (Functions And Mechanisms Of Ultraosund In Soy Protein Isolate (SPI)-Pectin Nannoemulsion Preparation)
Berichtszeitraum: 2020-10-01 bis 2022-09-30
According to the European Commission, in 2050, functional foods will constitute a substantial part of foods on the EU market, which will largely rely on innovation in improved additives. Nanoemulsions are under investigation as a mechanism for the delivery of bioactives to food systems, and are found to have benefits such as improving the taste and bioavailability of numerous ingredients. Recently, protein-polysaccharide complexes and conjugates are being developed for use in the creation of nanoemulsions. However, poor functionality and low production efficiency greatly limit their industrialisation. Therefore, this study proposes to introduce ultrasound technology to complexes/conjugates preparation, aiming at obtaining innovative nanoscale additives with strengthened efficiency and properties. Soy protein isolate (SPI) and pectin are selected as wall materials for nanoemulsion preparation. The objectives of this project include:
(1) To clarify the structure-function relationships of SPI-pectin complexes/conjugates and determine the optimum structures for electrostatic reaction and Maillard reaction respectively
(2) To prepare SPI-pectin complexes/conjugates using US treatment and illuminate the potential mechanisms
(3) To elucidate the effect of the formation mechanisms of nanoemulsions on their delivery functions
The results of this project will contribute to the industrial applications of ultrasound in food additive production, which, in turn, will promote the development of high-tech functional foods in the EU, and advance the goal of “sustainable production of food” proposed in Horizon 2020.
(1) To clarify the structure-function relationships of SPI-pectin complexes/conjugates and determine the optimum structures for electrostatic reaction and Maillard reaction respectively
(2) To prepare SPI-pectin complexes/conjugates using US treatment and illuminate the potential mechanisms
(3) To elucidate the effect of the formation mechanisms of nanoemulsions on their delivery functions
The results of this project will contribute to the industrial applications of ultrasound in food additive production, which, in turn, will promote the development of high-tech functional foods in the EU, and advance the goal of “sustainable production of food” proposed in Horizon 2020.
1. Work package (WP) 1:
We employed a dual modification strategy – a combination of pH-shifting and ultrasound (US) technology – for SPI modification; and employed alkaline or/and enzymatic treatments to modify pectin. Different modified SPI and pectin samples were then used to prepare the SPI-pectin complexes and conjugates.
The results showed that US remarkably enhanced the modification effect on SPI brought by pH-shifting. Dual modification on SPI also significantly accelerated the Maillard reaction, resulting in desirable structural and physicochemical properties of the final products. Furthermore, we found that the original pectin (without modification) was the optimum material for electrostatic complexation. However, an ideal grafting polysaccharide should possess a “moderate” Mw that is not too high to hinder the Maillard reaction, while still generating proper steric-hindrance effects for functional purpose. In this study, the enzymolysis pectin proved to be an optimum polysaccharide for conjugation with SPI.
Results exploitation: Results of this study will provide reference for material selection for preparation of protein-polysaccharide-based emulsifier in the industry and improve productivity, which will provide alternative low-cost additives for the food system.
2. WP2:
We employed a probe sonicator for complex/conjugate preparation. The reaction efficiency, yield, structural and functional properties of the final products prepared with and without US were compared.
The results indicated that the US cavitation effects resulted in structural modifications in both SPI and pectin, as well as enhanced their electrostatic interactions, which in combination contributed to the more desirable emulsifying properties of the complex. In addition, US significantly accelerated the grafting process and increased the surface hydrophobicity and emulsifying properties of the conjugates.
Results exploitation: The results indicated that US can be a desirable method for protein-polysaccharide complexation/conjugation, which could facilitate the application of US technology in the relevant industry. Furthermore, the incorporation of US into modern food processing could offer other significant benefits including high productivity, sustainability and greener processing.
3. WP3:
The SPI-pectin/β-carotene nanoemulsions were prepared with a microfluidizer. The relationship between the formation mechanisms of nanoemulsions and their delivery functions was analysed.
The results indicated that the complexation and conjugation of SPI with pectin significantly increased the stability and bioaccessibility of nanoemulsions. US treatment enhanced the stability of complexes/conjugates, resulting in better protective effects for β-carotene and more desirable controlled release. Furthermore, US increased the bioaccessibility for nanoemulsions stabilized by complexes. Despite the lower bioaccessibility of US-treated conjugates, US is still useful in accelerating the Maillard reaction and increasing the stability of the conjugates. In conclusion, US-prepared SPI–pectin complexes and conjugates have enormous potential in preparing emulsion-based systems for the delivery of hydrophobic nutrients, given their high stability and strong protective effects, as well as the high efficiency of the preparation procedures.
Results exploitation: In general, as the formation and preservation of electrostatic complexes have a strict requirement for pH, applications of the US-prepared complexes might be more suitable for acidic, liquid food matrices; applications of the conjugates are more flexible, which can be preserved in both solid and liquid states. This study advances the understanding of the delivery properties of protein–polysaccharide-based complexes and conjugates, as well as the merits that ultrasound provides when developing such binary systems.
4. Dissemination:
4.1 Conferences:
(1) 2023 MCAA Annual Conference and General Assembly, Córdoba, Spain, 24–25 February 2023.
(2) Ma, X., Miao, S. & Liu, D. Effects of structural modification of pectin by alkali or/and pectinase on the Maillard reaction with soy protein isolate. The 5th Food Structure and Functionality Symposium, Cork, Ireland, 18–21 September 2022. (Poster presentation)
(3) Ma, X. Functions and mechanisms of ultrasound in soy protein isolate (SPI)-pectin nanoemulsion preparation. The 1st Teagasc Food Research Day, Fermoy, Ireland, 28–29 September 2021. (Oral presentation)
4.2 Publications:
(1) Ma, X., Yan, T., Miao, S., Mao, L. & Liu, D. In Vitro Digestion and Storage Stability of β-Carotene-Loaded Nanoemulsion Stabilized by Soy Protein Isolate (SPI)-Citrus Pectin (CP) Complex/Conjugate Prepared with Ultrasound. Foods, 2022, 11(16), 2410.
(2) Ma, X., Chi, C., Pu, Y., Miao, S. & Liu, D. Conjugation of soy protein isolate (SPI) with pectin: effects of structural modification of the grafting polysaccharide. Food Chemistry, 2022, 387, 132876.
We employed a dual modification strategy – a combination of pH-shifting and ultrasound (US) technology – for SPI modification; and employed alkaline or/and enzymatic treatments to modify pectin. Different modified SPI and pectin samples were then used to prepare the SPI-pectin complexes and conjugates.
The results showed that US remarkably enhanced the modification effect on SPI brought by pH-shifting. Dual modification on SPI also significantly accelerated the Maillard reaction, resulting in desirable structural and physicochemical properties of the final products. Furthermore, we found that the original pectin (without modification) was the optimum material for electrostatic complexation. However, an ideal grafting polysaccharide should possess a “moderate” Mw that is not too high to hinder the Maillard reaction, while still generating proper steric-hindrance effects for functional purpose. In this study, the enzymolysis pectin proved to be an optimum polysaccharide for conjugation with SPI.
Results exploitation: Results of this study will provide reference for material selection for preparation of protein-polysaccharide-based emulsifier in the industry and improve productivity, which will provide alternative low-cost additives for the food system.
2. WP2:
We employed a probe sonicator for complex/conjugate preparation. The reaction efficiency, yield, structural and functional properties of the final products prepared with and without US were compared.
The results indicated that the US cavitation effects resulted in structural modifications in both SPI and pectin, as well as enhanced their electrostatic interactions, which in combination contributed to the more desirable emulsifying properties of the complex. In addition, US significantly accelerated the grafting process and increased the surface hydrophobicity and emulsifying properties of the conjugates.
Results exploitation: The results indicated that US can be a desirable method for protein-polysaccharide complexation/conjugation, which could facilitate the application of US technology in the relevant industry. Furthermore, the incorporation of US into modern food processing could offer other significant benefits including high productivity, sustainability and greener processing.
3. WP3:
The SPI-pectin/β-carotene nanoemulsions were prepared with a microfluidizer. The relationship between the formation mechanisms of nanoemulsions and their delivery functions was analysed.
The results indicated that the complexation and conjugation of SPI with pectin significantly increased the stability and bioaccessibility of nanoemulsions. US treatment enhanced the stability of complexes/conjugates, resulting in better protective effects for β-carotene and more desirable controlled release. Furthermore, US increased the bioaccessibility for nanoemulsions stabilized by complexes. Despite the lower bioaccessibility of US-treated conjugates, US is still useful in accelerating the Maillard reaction and increasing the stability of the conjugates. In conclusion, US-prepared SPI–pectin complexes and conjugates have enormous potential in preparing emulsion-based systems for the delivery of hydrophobic nutrients, given their high stability and strong protective effects, as well as the high efficiency of the preparation procedures.
Results exploitation: In general, as the formation and preservation of electrostatic complexes have a strict requirement for pH, applications of the US-prepared complexes might be more suitable for acidic, liquid food matrices; applications of the conjugates are more flexible, which can be preserved in both solid and liquid states. This study advances the understanding of the delivery properties of protein–polysaccharide-based complexes and conjugates, as well as the merits that ultrasound provides when developing such binary systems.
4. Dissemination:
4.1 Conferences:
(1) 2023 MCAA Annual Conference and General Assembly, Córdoba, Spain, 24–25 February 2023.
(2) Ma, X., Miao, S. & Liu, D. Effects of structural modification of pectin by alkali or/and pectinase on the Maillard reaction with soy protein isolate. The 5th Food Structure and Functionality Symposium, Cork, Ireland, 18–21 September 2022. (Poster presentation)
(3) Ma, X. Functions and mechanisms of ultrasound in soy protein isolate (SPI)-pectin nanoemulsion preparation. The 1st Teagasc Food Research Day, Fermoy, Ireland, 28–29 September 2021. (Oral presentation)
4.2 Publications:
(1) Ma, X., Yan, T., Miao, S., Mao, L. & Liu, D. In Vitro Digestion and Storage Stability of β-Carotene-Loaded Nanoemulsion Stabilized by Soy Protein Isolate (SPI)-Citrus Pectin (CP) Complex/Conjugate Prepared with Ultrasound. Foods, 2022, 11(16), 2410.
(2) Ma, X., Chi, C., Pu, Y., Miao, S. & Liu, D. Conjugation of soy protein isolate (SPI) with pectin: effects of structural modification of the grafting polysaccharide. Food Chemistry, 2022, 387, 132876.
The project results will promote the development of various dietary supplements encapsulated by safe and nutritious binary complexes/conjugates and stimulate the prosperity of the relevant food industries, bringing more jobs and sales and providing opportunities for the EU to improve its economic benefit by developing high-value food products. Furthermore, this project could promote the development of US instrument companies, contributing to the incorporation of US into modern food processing. This will nurture new businesses, create more high-value jobs, attract talents and power an innovative and enterprising economy.