A strategy for promoting γ-glutamyltransferase activity and enzymatic synthesis of S-allyl-(L)-cysteine in aged garlic via high hydrostatic pressure pretreatments

Ameliorating effect of S-Allyl cysteine (Black Garlic) on 6-OHDA mediated neurotoxicity in SH-SY5Y cell line

Therapeutic approaches based on isolated compounds derived from natural products are more common in preventing diseases involving inflammation and oxidative stress at present. S-allyl cysteine (SAC) is a promising garlic-derived organosulfur compound with many positive effects in cell models and living systems. SAC has biological activity in various fields, enclosing healing in learning and memory disorders, neurotrophic effects, and antioxidant activity. In this study, we purposed to identify the neuroprotective activity of SAC toward 6-OHDA-induced cell demise in the SH-SY5Ycell line. For this purpose, 6-OHDA-induced cytotoxicity, and biochemical, and gene expression changes were evaluated in SH-SY5Y cells. SH-SY5Y cells grown in cell culture were treated with SAC 24 h before and after 6-OHDA application. Then, cell viability, antioxidant parameters, and gene expressions were measured. Finally, immunofluorescence staining analysis was performed. Our results showed that SAC increased cell viability by 144 % at 80 µg/mL with pre-incubation (2 h). It was observed that antioxidant levels were significantly increased and oxidative stress marker levels were decreased in cells exposed to 6-OHDA after pre-treatment with SAC (p<0.05). SAC supplementation also suppressed the increase in pro-inflammation levels (TNF-α/IL1/IL8) caused by 6-OHDA (p < 0.05). While 8-OHdG and Nop10 expressions were observed at a mild level in SAC pretreatment depending on the dose, 8-OHdG, and Nop10 expressions were observed at a moderate level in SAC treatment after 6-OHDA application (p<0.05). Our findings demonstrate the positive effect of pretreatment with SAC on SH-SY5Y cells injured by 6-OHDA, suggesting that SAC may be beneficial for neuroprotection in regulating oxidative stress and neuronal survival in an in vitro model of Parkinson's disease.

Psychochemical changes and functional properties of organosulfur and polysaccharide compounds of black garlic (Allium sativum L.)

Background

Black garlic is one of the functional food products made from garlic which is processed through aging to improve sensory value and nutritional quality. Aging conditions has a major impact on the psychochemical and functional properties changes of black garlic which is closely related to organosulfur compounds and polysaccharides as the largest component in garlic.

Scope and approach

The method used in this research is a systematic review with the aim of research to determine the relationship between reactions during aging and changes in organosulfur, polysaccharides and non-enzymatic browning product compounds as well as the function of black garlic by focusing on certain aspects of aging including temperature, humidity, time, microorganism activity, and pre-treatment application.

Key findings and conclusions

Maillard reaction and polysaccharide degradation are still be the dominant reactions and play an important role in black garlic production. High hydrostatic pressure pretreatment could maintains the quality of black garlic so that the black garlic has the same taste characteristics as black garlic in general. Antioxidant properties in black garlic shown increase during thermal treatment. In addition, it is known that the activity of microorganisms plays a role and being potential to increase the quality value of black garlic as well as the antimicrobial activity.

Proposing Signaling Molecules as Key Optimization Targets for Intensifying the Phytochemical Biosynthesis Induced by Emerging Nonthermal Stress Pretreatments of Plant-Based Foods: A Focus on γ-Aminobutyric Acid

Emerging evidence has confirmed the role of emerging nonthermal stressors (e.g., electromagnetic fields, ultrasonication, plasma) in accumulating bioactive metabolites in plant-based food. However, the signal decoding mechanisms behind NonTt-driven phytochemical production remain unclear, hindering postharvest bioactive component intensification. This study aims to summarize the association between signaling molecules and bioactive secondary metabolite production under nonthermal conditions, demonstrating the feasibility of enhancing phytochemical accumulation through signaling molecule crosstalk manipulation. Nonthermal elicitors were found to be capable of inducing stress metabolisms and activating various signaling molecules, similar to conventional abiotic stress. A simplified pathway model for nonthermally induced γ-aminobutyric acid accumulation was proposed with reactive oxygen species and calcium signaling being versatile pathways responsive to nonthermal elicitors. Manipulating signal molecules/pathways under nonthermal conditions can intensify phytochemical biosynthesis. Further research is needed to integrate signaling molecule responses and metabolic network shifts in nonthermally stressed plant-based matrices, balancing quality modifications and intensification of food functionality potential.

The Impact of Different Pretreatment Processes (Freezing, Ultrasound and High Pressure) on the Sensory and Functional Properties of Black Garlic (Allium sativum L.)

Black garlic (BG) is an emerging derivative of fresh garlic with enhanced nutritional properties. This study aimed to develop functional BG products with good consumer acceptance. To this end, BG was treated with freezing (F-BG), ultrasound (U-BG), and HHP (H-BG) to assess its sensory and functional properties. The results showed that F-BG and H-BG had higher S-allyl-cysteine (SAC), polyphenol, and flavonoid contents than BG. H-BG and F-BG displayed the best sensory quality after 18 days of aging, while 5-hydroxymethylfurfural (5-HMF), SAC, and polyphenols were identified as the most influential sensory parameters. Moreover, the F-BG and H-BG groups achieved optimal taste after 18 days, as opposed to untreated BG, which needed more than 24 days. Therefore, the proposed approaches significantly reduced the processing time while enhancing the physical, sensory, and functional properties of BG. In conclusion, freezing and HHP techniques may be considered promising pretreatments to develop BG products with good functional and sensory properties.

S-Allyl cysteine in garlic (Allium sativum): Formation, biofunction, and resistance to food processing for value-added product development

S-allyl cysteine (SAC), which is the most abundant bioactive compound in black garlic (BG; Allium sativum), has been shown to have antioxidant, anti-apoptotic, anti-inflammatory, anti-obesity, cardioprotective, neuroprotective, and hepatoprotective activities. Sulfur compounds are the most distinctive bioactive elements in garlic. Previous studies have provided evidence that the concentration of SAC in fresh garlic is in the range of 19.0-1736.3 μg/g. Meanwhile, for processed garlic, such as frozen and thawed garlic, pickled garlic, fermented garlic extract, and BG, the SAC content increased to up to 8021.2 μg/g. BG is an SAC-containing product, with heat treatment being used in nearly all methods of BG production. Therefore, strategies to increase the SAC level in garlic are of great interest; however, further knowledge is required about the effect of processing factors and mechanistic changes. This review explains the formation of SAC in garlic, introduces its biological effects, and summarizes the recent advances in processing methods that can affect SAC levels in garlic, including heat treatment, enzymatic treatment, freezing, fermentation, ultrasonic treatment, and high hydrostatic pressure. Thus, the aim of this review was to summarize the outcomes of treatment aimed at maintaining or increasing SAC levels in BG. Therefore, publications from scientific databases in this field of study were examined. The effects of processing methods on SAC compounds were evaluated on the basis of the SAC content. This review provides information on the processing approaches that can assist food manufacturers in the development of value-added garlic products.