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Prolamins are a group of safe food additives that are biocompatible, biodegradable, and sustainable. Zein, gliadin, kafirin, and hordein are common prolamins that have been extensively studied, particularly as these form colloidal particles because of their amphiphilic properties. Prolamin-based binary/ternary complexes, which have stable physicochemical properties and superior functionality, are formed by combining prolamins with polysaccharides, polyphenols, water-soluble proteins, and surfactants. Although the combination of prolamins with other components has received attention, the relationship between the structural design of prolamin-based complexes and their functionalities remains uncertain. This review discusses the production methods of prolamin-based complexes, the factors influencing their structural characteristics, and their applications in the food industry. Further studies are needed to elucidate the structure-function relationships between prolamins and other biopolymers, as well as the toxicological effects of these complexes in food.

Antisolvent precipitation is a widely used method to fabricate prolamin-based composites. In the present study, composite structures of lysozyme amyloid fibrils with zein proteins were fabricated using the antisolvent precipitation method by applying different blending and pH adjustment sequences. Globular prolamins were bound to the amyloid fibrils to combine their respective advantages. The dynamic light scattering showed that the composites with a characteristic stabilized behavior (43.60 ± 1.75 mV ∼ 35.20 ± 0.65 mV) were formed at pH 4.0-5.0, in which noncovalent interactions between fibril and particles occurred. Two different structures: fruit tree-like structure and beaded-like structure, were presented in AFM and TEM images due to the different pH adjustment sequences, while blending sequences had negligible effect on the morphology of the composites. A fruit tree-like entity was detected for lysozyme fibril-zein composites, where its "branches" bear zein globular particles. A beaded-like structure was observed for lysozyme fibril-zein composites, where lysozyme fibril was the thread and zein aggregates were the beads. The potential mechanism of this phenomenon can be explained as the fruit tree-like structure being primarily formed through electrostatic interactions while the beaded-like structure is mainly caused by hydrophobic interactions. The composites of fruit tree-like structures hold a more promising stability than those with beaded-like structures. The results of this research would give constructive information for the fabrication of amyloid fibril-prolamin protein composites, which may exhibit the combined advantages of each components and have potential applications in encapsulation and protection of bioactive substances and stabilizing emulsions.

The antisolvent precipitation method is widely applied to produce zein colloidal particles. The process involves dissolving zein in 55-90% (v/v) alcohol/water mixtures and then shearing such solutions into deionized water to lower the ethanol content. In the present work, on the basis of the preliminary result that gum arabic (GA) was able to well disperse in 70% (v/v) alcohol/water mixtures, a new way was created to produce zein-GA nanocomposites by simply mixing their aqueous alcohol solution with a high alcohol level of 70% (v/v) at pH 8.0. Findings showed that the multimodal size distribution of zein or GA alone was shifted to be the monomodal peak after zein and GA aqueous ethanol solution was mixed, indicating the successful formation of zein-GA nanocomposites. A core-shell structure was observed for zein-GA nanocomposites, with zein as a core and GA as a shell. In addition, the incorporation of GA caused the conformational and second structural changes of zein. A two-step mechanism was involved to explain the formation of zein-GA nanocomposites. The first step was that GA addition changed the polarity of zein aqueous ethanol solution and zein nanoparticles formed, and the second step was that hydrogen bonds and hydrophobic interactions promoted the adsorption of GA onto the particle surfaces. Results in this work would provide a new sight into the design of zein-based nanocomplexes, which may have potential applications, such as constructing delivery systems, for bioactive compounds.

A series of novel structurally simple analogues based on nitidine was designed and synthesized in search of potent anticancer agents. The antitumor activity against human cancer cell lines (HepG2, A549, NCI-H460, and CNE1) was performed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay in vitro. The results showed that some of them had good anticancer activities, especially derivatives with a [(dimethylamino)ethyl]amino side chain in the C-6 position. Planar conjugated compounds 15a, 15b, and 15c, with IC50 values of 1.20 &mu, M, 1.87 &mu, M, and 1.19 &mu, M against CNE1 cells, respectively, were more active than nitidine chloride. Compound 15b and compound 15c with IC50 values of 1.19 &mu, M and 1.37 &mu, M against HepG2 cells and A549 cells demonstrated superior activities to nitidine. Besides, compound 5e which had a phenanthridinone core displayed extraordinary cytotoxicity against all test cells, particularly against CNE1 cells with the IC50 value of 1.13 &mu, M.