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BACKGROUND: The limited physicochemical properties (such as low foaming and emulsifying capacity) of mung bean protein hydrolysate restrict its application in the food industry. Ultrasound treatment could change the structures of protein hydrolysate to accordingly affect its physicochemical properties. The aim of this study was to investigate the effects of ultrasound treatment on the structural and physicochemical properties of mung bean protein hydrolysate of protamex (MBHP). The structural characteristics of MBHP were evaluated using tricine sodium dodecylsulfate–polyacrylamide gel electrophoresis, laser scattering, fluorescence spectrometry, etc. Solubility, fat absorption capacity and foaming, emulsifying and thermal properties were determined to characterize the physicochemical properties of MBHP. RESULTS: MBHP and ultrasonicated‐MBHPs (UT‐MBHPs) all contained five main bands of 25.8, 12.1, 5.6, 4.8 and 3.9 kDa, illustrating that ultrasound did not change the subunits of MBHP. Ultrasound treatment increased the contents of α‐helix, β‐sheet and random coil and enhanced the intrinsic fluorescence intensity of MBHP, but decreased the content of β‐turn, which demonstrated that ultrasound modified the secondary and tertiary structures of MBHP. UT‐MBHPs exhibited higher solubility, foaming capacity and emulsifying properties than MBHP, among which MBHP‐330 W had the highest solubility (97.32%), foaming capacity (200%), emulsification activity index (306.96 m2 g−1) and emulsion stability index (94.80%) at pH 9.0. CONCLUSION: Ultrasound treatment enhanced the physicochemical properties of MBHP, which could broaden its application as a vital ingredient in the food industry. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Zanthoxylum seed, as a low‐cost and easily accessible plant protein resource, has good potential in the food industry. But protein and its hydrolysates from Zanthoxylum seed are underutilized due to the dearth of studies on them. This study aimed to investigate the structure and physicochemical and biological activities of Zanthoxylum seed protein (ZSP) hydrolysates prepared using Protamex®, Alcalase®, Neutrase®, trypsin, or pepsin. RESULTS: Hydrolysis using each of the five enzymes diminished average particle size and molecular weight of ZSP but increased random coil content. ZSP hydrolysate prepared using pepsin had the highest degree of hydrolysis (24.07%) and the smallest molecular weight (<13 kDa) and average particle size (129.80 nm) with the highest solubility (98.9%). In contrast, ZSP hydrolysate prepared using Alcalase had the highest surface hydrophobicity and foaming capacity (88.89%), as well as the lowest foam stability (45.00%). Moreover, ZSP hydrolysate prepared using Alcalase exhibited the best hydroxyl‐radical scavenging (half maximal inhibitory concentration (IC50) 1.94 mg mL−1) and ferrous‐ion chelating (IC50 0.61 mg mL−1) activities. Additionally, ZSP hydrolysate prepared using pepsin displayed the highest angiotensin‐converting enzyme inhibition activity (IC50 0.54 mg mL−1). CONCLUSION: These data showed that enzyme hydrolysis improved the physicochemical properties of ZSP, and enzymatic hydrolysates of ZSP exhibited significant biological activity. These results provided validation for application of ZSP enzymatic hydrolysates as antioxidants and antihypertensive agents in the food or medicinal industries. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

To obtain different instant tea, three tea leaves (Pu'er tea, Gold Junmei tea and Tie Guanyin tea) were extrated by conventional (90 °C, 30 min) and pressurized (120 °C, 30 min) methods and dried in freezing and spraying condition. The amino acid composition and content were determined by the automatic amino acid analyzer, and the sensory evaluation was conducted. The yield and the content of free amino acids in instant tea powder was higher under the conditions of 120 °C pressurized hot extraction and freeze drying. The sensory evaluation showed freeze drying tea sample was more aromatic, better soluble, more mellow in taste, and it soup color was easier to accept than spray drying tea sample. [ABSTRACT FROM AUTHOR]

Aspergillus flavus is a notorious foodborne fungus, posing a significant risk to humans in the form of hepatocellular carcinoma or aspergillosis. Thymol, as a food preservative, could efficiently kill conidia of A. flavus. However, the underlying mechanisms by which thymol kills A. flavus are not completely understood. With specific fluorescent dyes, we detected several apoptotic hallmarks, including chromatin condensation, phosphatidylserine externalization, DNA damage, mitochondrial depolarization, and caspase 9 activation in conidia exposed to 200 μg/mL of thymol, indicating that thymol induced a caspase-dependent conidial apoptosis in A. flavus. Chemical-protein interactome (CPI) and autodock analyses showed that KCNAB, homologue to the β-subunit of the voltage-gated potassium channel (Kv) and aldo-keto reductase, was the potential target of thymol. Following studies demonstrated that thymol could activate the aldo-keto reductase activity of KCNAB in vitro and stimulate a transient K + efflux in conidia, as determined using a Port-a-Patch. Blocking K + eruption by 4-aminopyridine (a universal inhibitor of Kv) could significantly alleviate thymol-mediated conidial apoptosis, indicating that activation of Kv was responsible for the apoptosis. Taken together, our results revealed a K + efflux-mediated apoptotic pathway in A. flavus, which greatly contributed to the development of an alternative strategy to control this pathogen.

In the title compound, C(11)H(10)N(3)O(4)S(+)·Cl(-), the benzene ring makes an angle of 89.2 (1)° with the pyridinium ring. The dihedral angle between the nitro group and the benzene ring is 15.7 (1)°. The crystal structure is stabilized by N-H⋯Cl hydrogen bonds.