Maize comes in a variety of colors, including white, yellow, red, blue, and purple, which is due to the presence of phytochemicals such as carotenoids, anthocyanins, flavonoids, phytosterols, and some hydroxycinnamic acid derivatives. In Mexico, maize is primarily grown for human consumption; however, maize residues comprise 51–58% of the total maize plant weight (stalks, leaves, ears, and husks) and are mainly used as livestock feed. These residues contain numerous bioactive compounds that interest the industry for their potential health benefits in preventing or treating degenerative diseases. This review explores the current knowledge and highlights key aspects related to the extraction methods and different techniques for identifying the bioactive compounds found in maize by-products.

Cascalote pods are an important source of phenolic compounds, mainly recovered using solvent extraction methods. To find a sustainable alternative to these methods, this study aimed to evaluate solid-state fermentation (SSF) in order to enhance the extractability of total phenolic compounds (TPC) with antioxidant activity (AA) from cascalote pods. Aspergillus niger GH1 was selected based on the amount of TPC released and AA measured (ABTS, DPPH, FRAP) in a short period of time. Moreover, moisture, temperature, inoculum size, and mineral composition were evaluated. The largest amount of TPC released was 124.17 mg/gdw (g of dry weight) after 12 h of culture, which significantly correlated with the AA (Pearson’s R = 0.94). Moisture and KH₂PO₄ concentration were the main influencing factors of TPC release. Treatment 6 (1 × 10⁷ spores/gdw, 30 °C, 60% moisture, mineral composition (g/L): KH₂PO₄, 1.52; NaNO₃, 7.65; and MgSO₄, 1.52) was selected due to the highest values of both TPC and AA. SSF-assisted extraction allowed for an increase of 118% and 93% in TPC and AA values, respectively. Corilagin, lagerstannin, geraniin, and ellagic acid were the main phenolic compounds identified by RP-HPLC-ESI-MS in the cascalote extracts. The results obtained demonstrate the feasibility of SSF-assisted extraction as a biotechnological alternative for the recovery of important bioactive molecules from this underutilized material.

Cascalote pods are an important source of phenolic compounds, mainly recovered using solvent extraction methods. As a sustainable alternative, this study aimed to evaluate solid-state fermentation (SSF) to enhance the extractability of total phenolic compounds (TPC) with antioxidant activity (AA) from cascalote pods. Aspergillus niger GH1 was selected based on the amount of TPC released and AA measured (ABTS, DPPH, FRAP) in a shorter time. Moreover, moisture, temperature, inoculum size, and mineral composition were evaluated. The largest amount of TPC released was 124.17 mg/gdm (g of dry material) after 12 h of culture, strongly and highly significantly correlated with the AA. Moisture and KH2PO4 concentration were the main influencing factors on TPC release. Treatment 6 [1x 107 spores/gdm, 30 °C, 60% moisture, mineral composition (g/L): KH2PO4, 1.52; NaNO3, 7.65; and MgSO4, 1.52] was selected due to the highest values of both TPC and AA. SSF-assisted extraction allowed increase 118 % and 93 % in TPC and AA values, respectively. Corilagin, lagerstannin, geraniin, and ellagic acid were the main phenolic compounds identified by RP-HPLC-ESI-MS in cascalote extracts. The results obtained demonstrate the feasibility of SSF-assisted extraction as a biotechnological alternative for the recovery of important bioactive molecules from this underutilized material.

Corn, a widely cultivated cereal, is a rich source of several antioxidant compounds, including phenolic compounds. Some of these compounds are bound within the components of the corn cell wall, requiring specific treatments to release them. Solid-state fermentation (SSF) using Rhizopus oryzae enhanced the antioxidant capacity and phenolic content in legumes and grains. However, there is limited information regarding its application in blue corn. This study aimed to evaluate the effect of R. oryzae growth on the phenolic content and antioxidant capacity of blue corn kernels. The results demonstrated that R. oryzae used blue corn kernels for growth, which led to an increase in free phenolic compounds, reaching their highest concentration at 60 h of culture. Compared to the unfermented control (0 h), SSF increased by up to 161% in total phenolic content and a 94% increase in antioxidant capacity. The main phenolic compounds identified in the blue corn extracts at 60 h using RP-HPLC-ESI-MS included caffeic acid 4-O-glucoside, rosmanol, p-coumaroyl tartaric acid glucosidic ester, 5-heptadecylresorcinol, and caffeoyl tartaric acid. The SSF represents an eco-friendly method for enhancing the antioxidant capacity and phenolic compounds of blue corn grain.

Arthrospira platensis (Ap) and Bacillus coagulans (Bc) have been successfully used to develop functional foods, but not a combination of both regarding functional implications in nutritional value and antioxidant capacity. This work aimed to develop an artisanal wheat flour pasta with egg using 5% A. platensis and 1% B. coagulans GBI 6068 (Bc+Ap). Uncooked pasta was characterized regarding nutritional value; furthermore, total phenolic content, antioxidant capacity (by ABTS and FRAP), pigment content (chlorophyll a + b, and total carotenoids), colorimetry assay, textural profile analysis, buffering capacity and probiotic viability were carried out on uncooked and cooked pasta to assess the changes induced by cooking. The Bc+Ap pasta showed enhanced nutritional value with a significant increase in protein content (30.61%). After cooking, the pasta increased phenolic content (14.22% mg GAE/g), antioxidant capacity (55.59% µmol Trolox Equivalents/g and 10.88% µmol Fe+2/g) for ABTS and FRAP respectively, pigment content (6.72 and 1.17 mg/100g), for chlorophyll a+b and total carotenoids respectively, but relative positive impacts on colorimetric parameters in contrast to control (wheat flour pasta). Furthermore, Bc+Ap showed improved firmness (59%, measured in g), buffer capacity (87.80% μmol H+(g × ΔpH)−1), and good probiotic viability (7.2 ± 0.17 log CFU/g) after the cooking process.