Enrichment of gamma-aminobutyric acid in foods: From conventional methods to innovative technologies

 Food Res. Int. 162, Part A, 111801, 2022

Gamma-aminobutyric acid (GABA), a non-protein amino acid, possesses various health benefits and plays a signaling and defensive role in plants. Due to the low content of GABA in plant foods, scientists have made great efforts to enrich GABA in foods using various chemical, physical, and biological methods, including anaerobic treatment, cold, salt treatment, germination, microbial fermentation, crossbreeding, and innovative technologies such as ultrasound, ultraviolet, high pressure, etc. To effectively increase GABA in different foods, it is crucial to understand the underlying mechanisms and the virtues and limitations of different enrichment methods that are suitable for different foods. In this paper, we aimed to comprehensively review the recent progress on both conventional and innovative enrichment methods, the advantages and disadvantages, the associated mechanisms, and the applicable foods of these methods. We also summarized the functions of GABA in plants and microorganisms, the factors influencing GABA enrichment, the patents related to GABA enrichment, and the functional foods rich in GABA. The mechanisms of GABA enrichment mainly include modification of cell microstructure; influencing H+ and Ca2+ concentration and enzyme configuration, thereby activating glutamate decarboxylase; and regulation of gene and protein expression of enzymes involved in GABA biosynthesis and metabolism. This review will provide significant information on the production of GABA-enriched foods.

Terpenoid trans-caryophyllene inhibits weed germination and induces plant water status alteration and oxidative damage in adult Arabidopsis

Plant Biology

DOI: 10.1111/plb.12471

trans-Caryophyllene (TC) is a sesquiterpene commonly found as volatile component in many different aromatic plants. Although the phytotoxic effects of trans-caryophyllene on seedling growth are relatively explored, not many information is available regarding the phytotoxicity of this sesquiterpenes on weed germination and on adult plants. The phytotoxic potential of TC was assayed in vitro on weed germination and seedling growth to validate its phytotoxic potential on weed species. Moreover, it was assayed on the metabolism of Arabidopsis thaliana adult plants, through two different application ways, spraying and watering, in order to establish the primary affected organ and to deal with the unknown mobility of the compound. The results clearly indicated that TC inhibited both seed germination and root growth, as demonstrated by comparison of the ED50 values. Moreover, although trans-caryophyllene-sprayed adult Arabidopsis plants did not show any effect, trans-caryophyllene-watered plants became strongly affected. The results suggested that root uptake was a key step for the effectiveness of this natural compound and its phytotoxicity on adult plants was mainly due to the alteration of plant water status accompanied by oxidative damage.