The impact of processing on the release and antioxidant capacity of ferulic acid from wheat: A systematic review.

The antioxidant capacity and bioaccessibility of ferulic acid (FA)1 in wheat are highly limited by the lack of free ferulic acid (FFA).2 However, many studies claim that wheat processing can efficiently increase FFA content and ultimately influence the overall antioxidant capacity. Hence, this systematic review investigated changes in FFA content, antioxidant capacity and bioaccessibility of wheat after different processing treatments. A literature search of two databases (PubMed and Web of Science) was undertaken covering the last 20 years, yielding 1148 articles. Studies which employed bioprocessing, thermal processing and milling of wheat were considered. After exclusion criteria were applied, 36 articles were included. These covered single processing methods (n = 25, bioprocessing: n = 9, thermal processing: n = 9, milling n = 7) and combined processing methods (n = 11, bioprocessing & thermal processing = 7, bioprocessing, thermal processing & milling = 2, thermal processing & milling = 2). The total ferulic acid (TFA)3 content, degree of covalent bond hydrolysis and the percentage of FFA degraded or transformed to other compounds dominated the final changes in FFA content, antioxidant capacity and bioaccessibility. This systematic review is the first to comprehensively summarize the best efficient processing method for releasing FA and increasing antioxidant capacity and or bioaccessibility in wheat. The combination of particle size reduction, pre-hydrolysis thermal processing (except at high temperature and extended duration) and enzymatic hydrolysis (ferulic acid esterase (FAE)4 or fermentation) has the highest potential of releasing FA. However, the literature on the bioaccessibility of FA in wheat is limited and more work is required to demonstrate the link between the release of FA by processing and the consequent health benefits.

Enhanced stability and controlled gastrointestinal digestion of ß-carotene loaded Pickering emulsions with particle-particle complex interfaces.

In this study, we used large, rigid, and hydrophilic zein-propylene glycol alginate composite particles (ZPCPs) and small, soft, and hydrophobic whey protein microgel (WPM) particles to synergistically stabilize a Pickering emulsion for delivery of ß-carotene. The photothermal stability and storage stability of ß-carotene were improved with the combined use of different particles. Microstructural observations showed that ZPCPs were effectively adsorbed at the oil/water interface despite the substantial interparticle gaps. WPM particles could swell and stretch on the interface due to their deformable structure, thereby forming an interfacial layer of flattened particles to cover a large surface area. The interfacial structure and macroscopic properties of Pickering emulsions were modulated by adjusting the mass ratio and addition sequence of different particles. The combination of ZPCPs and WPM delayed the lipolysis during gastrointestinal digestion. Through controlling the composition of the complex interface, the free fatty acid (FFA) release rate of Pickering emulsions in the small intestinal phase was reduced from 15.64% to 9.03%. When ZPCPs were used as the inner layer and WPM as the outer layer and the mass ratio of ZPCPs to WPM was 4 : 1, the Pickering emulsion showed the best stability and ß-carotene bioaccessibility. The Pickering emulsion with particle-particle complex interfaces could be applied in foods and pharmaceuticals for the purpose of enhanced stability, delayed lipolysis or sustained nutrient release.