Formation, Evolution, and Antioxidant Activity of Melanoidins in Black Garlic under Different Storage Conditions

Abstract

Melanoidins (MLDs) are formed through the reaction of carbonyl compounds and amino compounds in the Maillard reaction (MR) during the heating or storage of food. In this study, the formation, chemical composition, and structural characteristics of black garlic (BG) MLDs stored at different temperatures (4 °C, 20 °C, and 35 °C) over a period of 6 months were investigated. The initial products of the MR formed more often at 4 °C and 20 °C, while higher temperatures (35 °C) promoted the reaction in the middle and late stages of the MR. The higher temperature promoted an increase in molecular weight and MLD content, which can be attributed to the increase in protein and phenolic content. Elemental analysis confirmed an increase in nitrogen (N) content and the continuous incorporation of nitrogen-rich substances into the skeleton. Amino acids, particularly aspartic acid and threonine, were the primary N-containing compounds involved in MLD formation. Additionally, the infrared analysis revealed that the changes in MLDs during storage were characterized by amide I and amide II groups. The MR enhanced the yields of heterocyclic compounds (from 56.60% to 78.89%), especially that of O-heterocyclic compounds, at the higher temperature according to Py-GC-MS analysis. Furthermore, the higher temperature enhanced the molecular weight, maximum height, and roughness of MLDs compared to the control. The antioxidant ability of MLDs was positively correlated with storage temperatures. In summary, temperature had an impact on the formation, evolution, and antioxidant activity of MLDs.

The Browning Properties, Antioxidant Activity, and α-Glucosidase Inhibitory Improvement of Aged Oranges (Citrus sinensis)

“…The AA group had a greater matrix concentration, leading to an accelerated browning reaction rate, possibly due to the formation of Maillard reaction intermediate products [36]. The A 420 value is commonly used to detect Maillard reaction intermediate products [15,17]. The absorbance of the black orange samples was quantified at a wavelength of 420 nm.…”

“…Vegetables and fruits frequently have browning responses as an aging process, resulting in a deeper color, firmer texture, the development of sweet and sour flavors, and an increase in scent [10][11][12][13][14]. Several sources indicate that aging enhances the antioxidant, anti-allergic, antidiabetic, anti-inflammatory, hypolipidemic, and anticancer characteristics of black garlic, black apple, and black bitter melon [15][16][17][18][19]. Aging technology causes enzymatic and non-enzymatic browning.…”

Anti-Cancer and Anti-Inflammatory Properties of Black Garlic

“…In recent years, there has been an increase in interest in the health-promoting properties of black garlic (BG) as a rich source of several bioactive compounds, mainly those with antioxidant properties [4,12]. It is obtained from raw garlic subjected to aging processes [13,14].…”