Influence of Innovative Processing on γ‐Aminobutyric Acid (GABA) Contents in Plant Food Materials

Abstract

Over the last several decades, γ -aminobutyric acid (GABA) has attracted much attention due to its diverse physiological implications in plants, animals, and microorganisms. GABA naturally occurs in plant materials and its concentrations may vary considerably, from traces up to μmol/g (dry basis) depending on plant matrix, germination stage, and processing conditions, among other factors. However, due to its important biological activities, considerable interest has been shown by both food and pharmaceutical industries to improve its concentration in plants. Natural and conventional treatments such as mechanical and cold stimulation, anoxia, germination, enzyme treatment, adding exogenous glutamic acid (Glu) or gibberellins, and bacterial fermentation have been shown effective to increase the GABA concentration in several plant materials. However, some of these treatments can modify the nutritional, organoleptic, and/or functional properties of plants. Recent consumer demand for food products which are "healthy," safe and, having added benefits (nutraceuticals/functional components) has led to explore new ways to improve the content of bioactive compounds while maintaining desirable organoleptic and physicochemical properties. Along this line, nonthermal processing technologies (such as high-pressure processing, pulsed electric fields, and ultrasound, among others) have been shown as means to induce the biosynthesis and accumulation of GABA in plant foods; and the main findings so far reported are presented in this review. Moreover, the most novel tools for the identification of metabolic response in plant materials based on GABA analysis will be also described.

4-Aminobutyrate (GABA): a metabolite and signal with practical significance

“…GABA levels that are two to times control levels have been reported (Table 4). Some of these treatments can modify the nutritional, organoleptic and functional properties of plants, so there is interest in inducing GABA accumulation in plant-derived foodstuffs using non-thermal technologies such as high-pressure processing (for review see Poojary et al 2017). The second main strategy involves genetic engineering of GAD Ox and/or GABA-T down-regulation, resulting in GABA levels in rice seed and tomato fruit which are five to 349 times the levels in the wild-type (Akama et al 2009;Shimarjiri et al 2013a;Nonaka et al 2017;Takayama et al 2015Takayama et al , 2017 ( Table 4).…”

Innovative processing techniques for altering the physicochemical properties of wholegrain brown rice (Oryza sativa L.) – opportunities for enhancing food quality and health attributes

“…For example, bioactive compounds present in WBR with antidiabetic effects include GABA, dietary fibers, γ-oryzanol, and resistant starch (RS) fraction. GABA is a non-protein amino acid and shares various physiological activities in mammals, such as functioning as neurotransmitter in the central nervous system, regulating blood pressure and heart rate, accelerating brain protein synthesis and relieving pain and anxiety (Diana, Quílez, & Rafecas, 2014;Gan et al, 2017;Poojary et al, 2017). Oral supplements with GABA significantly reduced the glycemic response and improved glucose tolerance in rat model, attributing to its enhanced secretion of insulin from the pancreas (Adeghate & Ponery, 2002;Tian et al, 2011).…”

Pulsed electric fields as an alternative to thermal processing for preservation of nutritive and physicochemical properties of beverages: A review

“…Thermal treatments have been traditionally used for food preservation, but heating can reduce their sensory and nutritional quality (Bursać Kovačević et al, ; Poojary, Putnik, et al, ). This steered engineering towards increased use of non‐thermal treatments for preservation and processing of foodstuffs (Barba et al, ; Herceg et al, ; Misra et al, ; Poojary, Dellarosa, et al, ; Zhu et al, ). In thermal treatments, elevated temperature inactivates microorganisms and enzymes, while non‐thermal methods for the same goal use alternative approaches able to diminish or alleviate temperature increase (Oey, Faridnia, et al, ; Poojary, Roohinejad, Koubaa, et al, ; Roohinejad et al, ).…”