As an important food crop, corn has an important impact on people’s lives. The processing of corn produces many by-products, such as corn gluten meal, corn husk, and corn steep liquor, which are rich in protein, oil, carbohydrates, and other nutrients, all of which are inexpensive. Their accumulation in large quantities during the production process not only results in a burden on the environment but also the loss of potentially valuable food materials that can be processed. In fact, the by-products of corn processing have been partially used in functional foods, nutrients, feed, and other industries. There is no doubt that the secondary utilization of these by-products can not only solve the problem of waste pollution caused by them, but also produce high value-added products and improve the economic benefits of corn. This paper describes in detail the processing and higher-value utilization of the five main by-products: corn gluten meal, corn husks, corn steep liquor, corn germ, and fuel ethanol by-product. The utilization status of corn processing by-products was discussed roundly, and the development trend of corn processing by-products in China and other countries was analyzed, which provided the reference for the development of the corn deep processing industry.

Zein and its derived peptides have been used as nanocarriers for bioactive components. Lutein, as well as other xanthophylls, are characterized by blue light filtering and anti-oxidant properties. However, lutein is unstable and has low water solubility, poor absorption, and low bioavailability. In order to protect lutein from oxidative degradation, and to enhance its solubility and dispersibility, stability and bioactivity, lutein-loaded zein nanoparticles (LLZ-NP) and zein-derived peptide nanoparticles (LLZ-PEP-NP) were prepared by the solvent diffusion method. Compared to LLZ-NP, LLZ-PEP-NP possessed good physicochemical properties, including particle size, polydispersity index, zeta potential, entrapment efficiency and in vitro stability. Specifically, transmission electron microscopy (TEM) images showed that LLZ-PEP-NP had a spherical form with a nanometric size and lutein was efficiently loaded into zein-derived peptides through self-assembly. Dynamic light scattering (DLS) results demonstrated that LLZ-PEP-NP had a narrow size distribution in the range of 200–300 nm and a decreased zeta potential compared to that of LLZ-NP. The lutein entrapment efficiency (EE%) of LLZ-NP and LLZ-PEP-NP was more than 85%, while LUT-PEP-NP showed higher lutein entrapment efficiency because of the better capacity of peptides bound with lutein. Nanoencapsulation of lutein into LLZ-PEP-NP resulted in a significantly higher solubility compared to nanoencapsulation of lutein into LLZ-NP and free lutein. The stabilities of lutein in zein-derived peptide nanoparticles in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) were improved. These results suggest that zein-derived peptides have the potential to be used as nanocarriers to enhance the solubility and stability of lutein, which can further improve its bioavailability.

Polypeptide decorated nanoliposomes were prepared as novel delivery systems to enhance the stability, release and bioactivity of lutein.

As a green and low-energy pretreatment method, the effect of freeze-thaw (FT) pretreatment on extraction yield and antioxidant bioactivity of carotenoids of the corn gluten meal (CGM) were evaluated in this study. The CGM particles ruptured in FT treatment due to the repeated damage caused by FT to CGM particles. The carotenoid compounds of pretreated CGM were lutein, zeaxanthin, β-carotene, and cryptoxanthin. Among them, the major carotenoids are lutein and zeaxanthin. The optimized FT pretreatment conditions included freezing temperature of −20°C, moisture content of 100%, and 2 cycles. An increase in the yield of lutein and zeaxanthin was observed in the range of 2.23–16.39 µg/g and 4.66–36.3 µg/g as a result of pretreatment as against 1.17 and 2.52 µg/g of the untreated sample, respectively. Moreover, the release of lutein and zeaxanthin from CGM was facilitated by FT pretreatment and increased the antioxidant activity of the carotenoids.

The concentration of OH⁻ can directly influence the crystal growth of flexible hydroxyapatite nanofibers in oleic acid-assisted solvothermal reaction systems.