Black Garlic and Its Bioactive Compounds on Human Health Diseases: A Review

Comparative Studies of Bioactivities and Chemical Components in Fresh and Black Garlics

To investigate the bioactivities of fresh garlic and its processed product, black garlic, we conducted comparative analyses of antioxidant, anti-inflammatory, innate immune activation, and anti-cancer activities in addition to the chemical composition (sugar, amino acid, and polyphenol contents) of these materials. Simultaneous assay using neutrophil-like cells showed that fresh garlic exhibited antioxidant and innate immunostimulatory activities, whereas black garlic displayed a potent anti-inflammatory effect. The antioxidant activity index was correlated with phenol and flavonoid contents, while the innate immunostimulatory activity was correlated with fructan content. Furthermore, some black garlics with low fructose content were found to inhibit the proliferation of UM-UC-3 cancer cells, while other black garlics rich in fructose increased UM-UC-3 cell proliferation. It was shown that the processing of fresh garlic could change the composition of sugars, antioxidants, and amino acids, which have different effects on neutrophil-like cells and UM-UC-3 cells, as well as on bioactivities.

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.

Types of Nursing Intervention on Improving Quality of Life among Patients with Diabetes Mellitus: A Systematic Review

BACKGROUND

Long-term treatment of patients with diabetes mellitus (DM) is considered a major factor causing disease complications. DM complications mostly impact the patient's quality of life (QoL). Only a few studies have been conducted summarizing the types of nursing interventions for improving the QoL of DM patients.

OBJECTIVE

The objective of this study is to explore the types of nursing interventions that can improve the QoL of DM patients.

METHODS

The online databases, including ScienceDirect, Medline, Google Search, and Pro-Quest, were used to search for the relevant articles. Articles that met the inclusion criteria were analyzed, and their level of evidence was determined and synthesized.

RESULTS

A total of 30 articles defining the types of nursing intervention on improving the QoL of DM patients were discovered, comprising the five types of nursing interventions, such as health education (15 articles), exercise (8 articles), WhatsApp/short message service (WA/SMS) gateway (3 articles), blood glucose control (3 articles), and black garlic herbal therapy (1 article).

CONCLUSION

Sequentially, the most common types of nursing interventions to improve the QoL of DM patients was health education, followed by exercise, WA/SMS gateway, and glucose control. A personal approach to health education is a significant point in improving the QoL of DM patients in the future. The findings of this study might not be strongly generalized, so further randomized controlled trial (RCT) studies with larger samples are needed.

Elephant Black Garlic's Beneficial Properties for Hippocampal Neuronal Network, Chemical Characterization and Biological Evaluation

Garlic has been used for decades as an important food and additionally for its beneficial properties in terms of nutrition and ancestral therapeutics. In this work, we compare the properties of fresh (WG) and aged (BG) extract obtained from elephant garlic, harvested on Chiloe Island, Chile. BG was prepared from WG with a 20-day aging process under controlled temperature and humidity conditions. We observed that in BG, compounds such as diallyl disulfide decrease, and compounds of interest such as 5-hydroxymethylfurfural (69%), diallyl sulfide (17%), 3H-1,2-Dithiole (22%) and 4-Methyl-1,2,3-trithiolane (16%) were shown to be increased. Using 2,2-diphenyl-1-picrylhydrazyl (DPPH, BG: 51 ± 5.7%, WG: 12 ± 2.6%) and 2,20-azino-bis-(3-ethylbenzothiazoline-6 sulfonate) diammonium salt (ABTS, BG: 69.4 ± 2.3%, WG: 21 ± 3.9%) assays, we observed that BG possesses significantly higher antioxidant activity than WG and increased cell viability in hippocampal slices (41 ± 9%). The effects of WG and BG were shown to improve the neuronal function through an increased in intracellular calcium transients (189 ± 4%). In parallel, BG induced an increase in synaptic vesicle protein 2 (SV-2; 75 ± 12%) and brain-derived neurotrophic factor (BDNF; 32 ± 12%) levels. Thus, our study provides the initial scientific bases to foster the use of BG from Chiloe Island as a functional food containing a mixture of bioactive compounds that may contribute to brain health and well-being.

The Effect of Black Garlic on the Volatile Compounds in Heat-Treated Sucuk

This study aimed to determine the influence of using black garlic (BG) at different levels on organic volatile compounds in heat-treated sucuk (HTS), a semi dry fermented sausage. Three independent batches of sausages were prepared: control: 1% white garlic (WG): WG-1%; BG-1%: 1% BG; BG-2%: 2% BG; and BG-3%: 3% BG. After stuffing, the sausages were subjected to fermentation, heat treatment (internal temperature of 64 °C), and drying, respectively. After production, the final products were analyzed for volatile compounds. A solid-phase microextraction technique was used for the extraction of volatile compounds, and identification was carried out by a gas chromatograph/mass spectrometer. A total of 47 volatile compounds, including sulfur compounds, alcohols, esters, ketones, aliphatic hydrocarbons, acids, aromatic hydrocarbons, aldehydes, and terpenes, were identified from the sausages. The use of BG in HTS had no significant effect on aliphatic hydrocarbons, acids, ketones, aromatic hydrocarbons, and esters. BG increased the abundances of 2-propen-1-ol, allyl methyl sulfide, methyl 2-propenyl-disulfide, sabinene, β-pinene, and β-phellandrene regardless of the increase in the addition rate. BG-3% increased the level of hexanal. According to the PCA results, BG-containing groups showed positive correlation with esters, sulfur compounds, aldehydes, aromatic hydrocarbons, and alcohols, but these chemical groups were more closely correlated with BG-3%. In addition, diallyl disulfide, which is one of the main factors that causes the pungent and spicy smell of garlic, showed a close correlation with WG-1%.

Effect of Black Garlic Consumption on Endothelial Function and Lipid Profile: A Before-and-After Study in Hypercholesterolemic and Non-Hypercholesterolemic Subjects

BACKGROUND

Black garlic is obtained from raw garlic (Allium sativum L.), by a fermentation process, under humidity and heat treatment, showing a high concentration of organosulfur compounds, which have been related to benefits in the prevention or delay of cardiovascular diseases (CVDs). The objective of the research was to evaluate whether long-term consumption of black garlic improves endothelial function and lipid profile in subjects with hypercholesterolemia.

METHODS

Single center, controlled clinical trial with two branches: Hypercholesterolemia vs. Healthy condition. Sixty-two subjects of both sexes were distributed in two groups, the hypercholesterolemia group (n = 31) (total cholesterol (TC) range 200-300 mg/dL and low-density lipoprotein (LDL)-cholesterol range 135-175 mg/dL) and the healthy group (n = 31). The intervention consisted of the ingestion of 4 cloves of black garlic (12 g) daily for 12 weeks.

RESULTS

significant increases in Apolipoprotein (Apo)A1 occurred in both groups: Hypercholesterolemia (Δ 11.8 mg/dL p < 0.001) vs Healthy (Δ 11.1 mg/dL p < 0.001). Besides, significant reductions for endothelial adhesion molecules monocyte chemoattractant protein-1 (MCP-1) (Δ -121.5 pg/mL p = 0.007 vs. Δ -56.3 pg/mL p = 0.015), intracellular adhesion molecule-1 (ICAM-1) (Δ -39.3 ng/mL p < 0.001 vs. Δ 63.5 ng/mL p < 0.001), and vascular cyto-adhesion molecule-1 (VCAM-1) (Δ -144.4 ng/mL p < 0.001 vs. Δ -83.4 ng/mL p = 0.061) were observed, for hypercholesterolemic and healthy subjects, respectively.

CONCLUSIONS

These data show that black garlic consumption could improve some parameters related to endothelial function and lipid profile, which may have a favorable impact on the risk of CVDs, although more long-term studies are necessary to confirm.

Simultaneous microwave-assisted extraction of bioactive compounds from aged garlic

In this work, the simultaneous extraction of bioactives (organosulfur compounds, such as S-allyl-L-cysteine (SAC), carbohydrates, such as neokestose and neonystose, and total phenolic compounds) from aged garlic has been optimized for the first time to obtain multifunctional extracts for further application as food ingredients. Analytical methods using liquid chromatography coupled to mass spectrometry (HPLC-MS) and by hydrophilic interaction liquid chromatography with evaporative light scattering detection (HILIC-ELSD) were also previously optimized. High sensitivity (limits of detection between 0.013 and 0.77 µg mL^-1) and appropriate repeatability (< 12%) and accuracy (> 92%) for the analysis of bioactives were achieved. After selecting water as the extraction solvent and microwave-assisted extraction (MAE) as the most efficient technique, operation conditions were optimized using a Box-Behnken experimental design (60 min; 120 °C; 0.05 g mL^-1; 1 cycle) to maximize the content of bioactives from different aged garlic samples. Regarding organosulfur compounds, only SAC (traces-2.32 mg g^-1 dry sample) and cycloalliin (1.23-3.01 mg g^-1 dry sample) were detected in all samples, while amino acids such as arginine (0.24-3.45 mg g^-1 dry sample) and proline (0.43-3.91 mg g^-1 dry sample) were, in general, the most abundant. Bioactive carbohydrates (from trisaccharides to nonasaccharides) were only detected in fresh garlic and aged garlic processed under mild conditions, whereas all garlic extracts showed antioxidant activity. The developed MAE methodology is shown as a successful alternative to other procedures for the simultaneous extraction of aged garlic bioactives intended by the food and nutraceutical industries, among others.

Bioavailability of Organosulfur Compounds after the Ingestion of Black Garlic by Healthy Humans

The consumption of black garlic has been related to a decreased risk of many human diseases due to the presence of phytochemicals such as organosulfur compounds (OSCs). However, information on the metabolization of these compounds in humans is limited. By means of ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS), this study aims to determine the OSCs and their metabolites excreted in urine 24 h after an acute intake of 20 g of black garlic by healthy humans. Thirty-three OSCs were identified and quantified, methiin (17,954 ± 6040 nmol), isoalliin (15,001 ± 9241 nmol), S-(2-carboxypropyl)-L-cysteine (8804 ± 7220 nmol) and S-propyl-L-cysteine (deoxypropiin) (7035 ± 1392 nmol) being the main ones. Also detected were the metabolites N-acetyl-S-allyl-L-cysteine (NASAC), N-acetyl-S-allyl-L-cysteine sulfoxide (NASACS) and N-acetyl-S-(2-carboxypropyl)-L-cysteine (NACPC), derived from S-allyl-L-cysteine (SAC), alliin and S-(2-carboxypropyl)-L-cysteine, respectively. These compounds are potentially N-acetylated in the liver and kidney. The total excretion of OSCs 24 h after the ingestion of black garlic was 64,312 ± 26,584 nmol. A tentative metabolic pathway has been proposed for OSCs in humans.

Anti-Inflammatory and Vasorelaxant Effects Induced by an Aqueous Aged Black Garlic Extract Supplemented with Vitamins D, C, and B12 on Cardiovascular System

Multiple studies demonstrated biological activities of aged black garlic, including anti-inflammatory, antioxidant, and cardioprotective effects. We aimed to investigate the protective effects of an aged black garlic water extract (ABGE) alone or in association with multivitamins consisting of combined Vitamins D, C, and B12, on mouse heart specimens exposed to E. coli lipopolysaccharide (LPS). Moreover, we studied the hydrogen sulphide (H₂S) releasing properties and the membrane hyperpolarization effect of the Formulation composed by ABGE and multivitamins, using Human Aortic Smooth Muscle Cells (HASMCs). ABGE, vitamins D and C, and the Formulation suppressed LPS-induced gene expression of cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-α, interleukin (IL)-6, nuclear factor-kB (NF-kB), and inducible nitric oxide synthase (iNOS) on mouse heart specimens. The beneficial effects induced by the extract could be related to the pattern of polyphenolic composition, with particular regard to gallic acid and catechin. The Formulation also increased fluorescence values compared to the vehicle, and it caused a significant membrane hyperpolarization of HASMCs compared to ABGE. To conclude, our present findings showed that ABGE, alone and in association with multivitamins, exhibited protective effects on mouse heart. Moreover, the Formulation increased intracellular H₂S formation, further suggesting its potential use on cardiovascular disease.

Effect of Black Garlic on Microbiological Properties, Lipid Oxidation, Residual Nitrite, Nitrosamine Formation and Sensory Characteristics in a Semi-Dry Fermented Sausage

This study was conducted with the aim of determining the effects of different black garlic (BG) levels (1%, 2% and 3%) on quality characteristics of a semi-dry fermented sausage (heat-treated sucuk). In addition, the effect of cooking time (0, 1 or 3 min at 180 °C on a hot plate) on nitrosamine formation was investigated. Fresh garlic (FG, 1%) was evaluated as the control group. BG (2% and 3%) caused a reduction in the count of lactic acid bacteria while leading to an increase in pH. FG1% gave the highest number of Micrococcus/Staphylococcus, as well as aw value. The thiobarbituric acid reactive substance (TBARS) value increased with increasing BG levels. FG (1%) showed the highest residual nitrite amount (p < 0.05). The scores for color, taste and general acceptability were reduced by the use of BG (p < 0.05). No significant difference was observed between the garlic treatments in terms of N-Nitrosodimethylamine (NDMA) and N-Nitrosodiethylamine (NDEA) when no additional cooking was applied. Cooking time was determined to have no significant effect on NDMA in 3% BG. The use of BG caused an increase in N-Nitrosopiperidine (NPIP) (p < 0.05). As for PCA, a closer correlation between NPIP and the groups containing BG was observed, while there was a strong correlation between NDMA and the FG group cooked for 3 min. The use of BG caused an increase in NPIP, but affected NDMA and NDEA depending on the cooking time.

Effect of Thermal Processes on S-Allyl Cysteine Content in Black Garlic

As a key component of black garlic (BG) products, S-allyl cysteine (SAC) is useful in reducing oxidative stress and inflammation. Several BG products with a high SAC content have been developed by thermal processing; however, the optimum conditions for thermal treatment for producing Thai garlic (multicloves) with a high SAC content compared to Chinese garlic (single clove) are still unknown. Moreover, the mechanism underlying the increase in SAC content in BG is unclear. Thus, this study aimed to investigate the optimum thermal condition for developing Thai BG with high SAC content base on methods A (70 °C and 80% RH) and B (60–75 °C and 80–85% RH). The total phenolic contents and antioxidant activities of Thai fresh garlic, Thai BG, and their powder forms were also compared. Method A worked the best for both types of garlic. The results indicated that the SAC content increased significantly after 7 days of fermentation and decreased drastically afterward with prolonged heat treatment. The optimum thermal condition for producing Thai fresh garlic and Chinese fresh garlic with high SAC content was 70 °C and a relative humidity of 80% for 12 days in an industrial fermentation chamber. The SAC content of Thai BG and Chinese BG increased approximately 139- and 122-fold, respectively. Furthermore, significant antioxidant capabilities determined by ferric ion-reducing antioxidant power, 2,2-diphenyl-1-picrylhydrazyl radical scavenging, and oxygen radical absorbance capacity assays were 34-, 6-, and 3-fold higher, respectively, than those of fresh garlic.

Determination of d- and l-Amino Acids in Garlic Foodstuffs by Liquid Chromatography-Tandem Mass Spectrometry

Black garlic is currently attracting interest as a health food and constituent of commercial supplements; however, no data regarding the d-amino acids within black garlic have been reported. Therefore, the amino acid compositions of methanol extracts from fresh and black garlic were compared herein. We investigated the contents of the d- and l-forms of amino acids in commercial fresh, black, and freeze-dried garlic foodstuffs by liquid chromatography-tandem mass spectrometry (LC-MS/MS) using a pre-column chiral derivatization reagent, succinimidyl 2-(3-((benzyloxy)carbonyl)-1-methyl-5-oxoimidazolidin-4-yl) acetate. Several d-amino acids, namely, the d-forms of Asn, Ala, Ser, Thr, Glu, Asp, Pro, Arg, Phe, Orn, Lys, and Tyr, were observed in the methanol extract of black garlic, whereas only d-Ala was detected in that of fresh garlic foodstuffs. These data suggest that several d-amino acids can be produced during fermentation for preparing black garlic.

Secukinumab and Black Garlic Downregulate OPG/RANK/RANKL Axis and Devitalize Myocardial Interstitial Fibrosis Induced by Sunitinib in Experimental Rats

Sunitinib has been associated with several cardiotoxic effects such as cardiac fibrosis. The present study was designed to explore the role of interleukin (IL)-17 in sunitinib-induced myocardial fibrosis (MF) in rats and whether its neutralization and/or administration of black garlic (BG), a form of fermented raw garlic (Allium sativum L.), could extenuate this adverse effect. Male Wistar albino rats received sunitinib (25 mg/kg three times a week, orally) and were co-treated with secukinumab (3 mg/kg, subcutaneously, three times total) and/or BG (300 mg/kg/day, orally) for four weeks. Administration of sunitinib induced significant increase in cardiac index, cardiac inflammatory markers, and cardiac dysfunction that were ameliorated by both secukinumab and BG, and to a preferable extent, with the combined treatment. Histological examination revealed disruption in the myocardial architecture and interstitial fibrosis in cardiac sections of the sunitinib group, which were reversed by both secukinumab and BG treatments. Both drugs and their co-administration restored normal cardiac functions, downregulated cardiac inflammatory cytokines, mainly IL-17 and NF-κB, along with increasing the MMP1/TIMP1 ratio. Additionally, they attenuated sunitinib-induced upregulation of the OPG/RANK/RANKL axis. These findings highlight another new mechanism through which sunitinib can induce interstitial MF. The current results propose that neutralizing IL-17 by secukinumab and/or supplementation with BG can be a promising therapeutic approach for ameliorating sunitinib-induced MF.

The Effect of Nonthermal Pretreatment on the Drying Kinetics and Quality of Black Garlic

Black garlic is obtained from regular garlic (Allium sativum L.) through the aging process and consequently gains many health-promoting properties, including antidiabetic and antioxidant. However, the material is still prone to microbiological deterioration and requires a long time to dry due to its properties. Therefore, this study aimed to investigate the effect of various drying methods on the quality of black garlic as well as determine the influence of selected nonthermal pretreatments on the drying kinetics and quality of black garlic, which is especially important in the case of the materials that are difficult to dry. The Weibull model was chosen to describe drying kinetics. Additionally, color, water activity together with antioxidant activity, phenolic compounds, and antidiabetic potential were determined. This study found that the application of a pulsed electric field (PEF), a constant electric field (CEF) as well as a magnetic field (MF) significantly reduced the time of drying (by 32, 40, and 24 min for a PEF, a CEF, and a MF, respectively, compared to combined drying without the pretreatment), and resulted in high antidiabetic potential. However, the highest content of phenolic compounds (1123.54 and 1125.36 mg/100 g dm for VMD125 and CD3h-VMD, respectively) and antioxidant capacity (ABTS = 6.05 and 5.06 mmol Trolox/100 g dm for VMD500 and CD6h-VMD, respectively) were reported for black garlic treated by vacuum-microwave drying and combined convective pre-drying followed by vacuum-microwave drying. Overall, the nonthermal pretreatment decreased the time of drying and showed very good efficiency in maintaining the antidiabetic potential of black garlic, especially in the case of the materials pretreated by a constant electric field (IC₅₀ = 99 and 56 mg/mL, for α-amylase and α-glucosidase, respectively).

Garlic (Allium sativum L.) in diabetes and its complications: Recent advances in mechanisms of action

Diabetes mellitus (DM) is a metabolic disease characterized by chronic hyperglycemia and impaired islet secretion that places a heavy burden on the global health care system due to its high incidence rate, long disease course and many complications. Fortunately, garlic (Allium sativum L.), a well-known medicinal plant and functional food without the toxicity and side effects of conventional drugs, has shown positive effects in the treatment of diabetes and its complications. With interdisciplinary development and in-depth exploration, we offer a clear and comprehensive summary of the research from the past ten years, focusing on the mechanisms and development processes of garlic in the treatment of diabetes and its complications, aiming to provide a new perspective for the treatment of diabetes and promote the efficient development of this field.

Black garlic: A review of its biological significance

Garlic has been used as a vegetable since ancient times, and it has proved versatility in preventative and therapeutic approaches. The use of garlic in the food business was restricted because of its strong flavor and harsh odor. Fermentation and different chemical processes, such as the Millard reaction and microbial fermentation, produce black garlic. Thermal processing at precise temperatures and relative humidity enhanced flavor and prolonged shelf life. This article holds the most up-to-date information about the resourcefulness and complexity of garlic processing and its biological implications. Recent findings have shown proof of the superior qualitative features and physical activities of black garlic. Before introducing this to the food market, researchers must conduct high-quality research to evaluate the changes of metabolites to achieve largest antioxidant, anticancer, anti-obesity, anti-inflammatory, immune, hepatoprotective, cardioprotective, neuroprotective, and anti-allergenic performance. Researchers should evaluate the quality, marketing, post-harvest handling, and consumption practices of black garlic.

Insights into flavor and key influencing factors of Maillard reaction products: A recent update

During food processing, especially heating, the flavor and color of food change to a great extent due to Maillard reaction (MR). MR is a natural process for improving the flavor in various model systems and food products. Maillard reaction Products (MRPs) serve as ideal materials for the production of diverse flavors, which ultimately improve the flavor or reduce the odor of raw materials. Due to the complexity of the reaction, MR is affected by various factors, such as protein source, hydrolysis conditions, polypeptide molecular weight, temperature, and pH. In the recent years, much emphasis is given on conditional MR that could be used in producing of flavor-enhancing peptides and other compounds to increase the consumer preference and acceptability of processed foods. Recent reviews have highlighted the effects of MR on the functional and biological properties, without elaborating the flavor compounds obtained by the MR. In this review, we have mainly introduced the Maillard reaction-derived flavors (MF), the main substances producing MF, and detection methods. Subsequently, the main factors influencing MF, from the selection of materials (sugar sources, protein sources, enzymatic hydrolysis methods, molecular weights of peptides) to the reaction conditions (temperature, pH), are also described. In addition, the existing adverse effects of MR on the biological properties of protein are also pointed out.

Preparation and structure-activity relationship of highly active black garlic polysaccharides

The aim of this study was to establish a method to improve the biological activity of polysaccharides. Three acid-treated polysaccharides (BGPS-2, BGPS-3 and BGPS-4) were obtained by treating black garlic polysaccharides (BGPS-1) with sulfuric acid at different intensities. The structure was characterized using the sulfuric acid-carbazole assay, IC, HPSEC-MALLS and FT-IR. The biological functions were evaluated using antioxidant and melanin biosynthesis inhibition assays. Compared with BGPS-1, the molecular weight of acid-treated polysaccharides significantly decreased, and the uronic acid content significantly increased. Antioxidant capacity negatively correlated with molecular weight, whereas melanin inhibition activity positively correlated with uronic acid content. BGPS-4 had the highest antioxidant capacity and the lowest molecular weight (1.25 × 10³ Da), 79.41 % lower than that of BGPS-1. BGPS-3 was the strongest inhibitor of melanin formation and had the highest uronic acid content (50.73 %), 238.2 % higher than that of BGPS-1. Molecular weight and uronic acid content were the main structural characteristics that affected the antioxidant and melanin biosynthesis inhibition activities, respectively. BGPS-1, BGPS-2, BGPS-3, and BGPS-4 all had β-linked pyranose, multi-branched, and non-triple helical spiral structures. Therefore, the acid hydrolysis method markedly modified the structural characteristics of black garlic polysaccharides, and increased their antioxidant capacity and melanin biosynthesis inhibition activity.

The shortest innovative process for enhancing the S-allylcysteine content and antioxidant activity of black and golden garlic

Black garlic is a type of heat-treated garlic for which the traditional process is extremely simple yet time-consuming, taking more than one month. The purpose of this research was to reduce the processing time of black garlic while maintaining a high level of S-allylcysteine (SAC), a black garlic quality indicator. The fresh garlic was pre-treated with CaCl₂ and frozen before being further incubated at two different temperatures (60 and 80 °C) with a relative humidity of 65% and 80% RH. Results showed that sequential pre-treatment and incubation at 80 °C and 80% RH for 1 week yielded 874.26 mg of SAC/100 g dry weight with an antioxidant activity of 5390 and 25,421 mg Trolox/100 g for DPPH and ABTS assays, respectively. This process shortened the processing time of black garlic by about 4-times. The batch processed at 60 °C and 65% RH for 1 week provided the highest SAC content of about 1772 mg/100 g dry weight, which was 2-times higher than in incubation at 80 °C and 80% RH for 1 week. The colour of this garlic was golden, so we call this new processed garlic product “golden garlic”.

S-allylcysteine potently protects against PhIP-induced DNA damage via Nrf2/AhR signaling pathway modulation in normal human colonic mucosal epithelial cells

SCOPE

This study aimed to investigate whether S-allylcysteine (SAC) exerts chemoprophylactic effects on foodborne carcinogenicity caused by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in normal human colonic mucosal epithelial cells.

METHODS AND RESULTS

Cellular thermal shift assays showed that SAC had an affinity for the Keap1 protein. Moreover, SAC may also dampen the binding of Keap1 and NF-E2-related factor 2 (Nrf2) by inhibiting p-p38 and increasing the phosphorylation of ERK1/2 and AKT, thereby inducing Nrf2/HO-1 signaling and upregulating the ratio of GSH to GSH/GSSG, which inhibits PhIP-induced oxidative stress and DNA damage. In addition, SAC significantly downregulates the aryl hydrocarbon receptor signaling pathway, suggesting that SAC may potentially impede the metabolic transformation of carcinogens.

CONCLUSION

Collectively, these findings suggest that SAC protects against PhIP-induced reactive oxygen species production and DNA damage by modulating the Nrf2/AhR signaling pathway, which may have significant potential as a novel chemopreventive agent. This article is protected by copyright. All rights reserved.

Alterations in the Physicochemical Properties and Antioxidant Activity during Aging of Stored Raw Garlic

Garlic, a once-a-year crop, is mass-produced in a single event. Most of the garlic harvested during the year, unless consumed or processed immediately, should be stored. Stored raw garlic (SRG) can be used to make black garlic (BG) via aging, and storage may affect the properties and quality of the BG compared with the use of raw garlic that has not been stored. This study was performed to identify the effect of long-term storage of raw garlic on the quality of BG products. SRG was aged for 21 days at 40–86 °C for BG production. Moisture content and pH gradually decreased with the aging period. Total phenolic, total flavonoid, and fructose contents were significantly increased during the aging period. Compared with non-stored raw garlic (NSRG), alliin and S-allylcysteine (SAC) contents were 1.7-fold and 5.9-fold higher in SRG, respectively, and γ-glutamyl-S-allylcysteine (γ-GSAC) content was 2.8-fold lower in SRG. The contents of alliin and γ-GSAC reduced as the aging period of SRG and NSRG progressed. However, the SAC content of NSRG increased with aging, but the SAC content of SRG decreased or increased slightly with extended aging. The antioxidant activity was also higher in BG made from NSRG rather than SRG. These results show that the SAC content is relatively low in BG manufactured from SRG compared with NSRG. Our findings suggest that it is necessary to establish an aging method suitable for SRG in BG production with high SAC content, a representative indicator of BG.

The Physicochemical Properties, Volatile Compounds and Taste Profile of Black Garlic (Allium sativum L.) Cloves, Paste and Powder

Black garlic is produced as a result of the so-called “fermentation processes” of whole heads or cloves kept under controlled conditions of temperature and humidity for several weeks. During this long-term heat treatment, garlic undergoes enzymatic and non-enzymatic browning reactions, which greatly change its taste, aroma, physicochemical, organoleptic and bioactive properties. Black garlic is most often produced in the form of cloves, and recently also in the form of paste and powder. This work focused on the comparison of functional properties of black garlic, such as volatile compounds, taste profile, total polyphenols content, antioxidant activity, color (CIE L*, a*, b*), water activity (aw), pH, soluble solids content (°Brix) and moisture content, depending on the form of its occurrence: cloves, spreading paste and powder. After long-term heat treatment, garlic was characterized by a higher content of dry matter and water-soluble solids, respectively at about 22% and 24% for spreading paste and 166% and 44% for powder. The conducted research showed significant differences in the bioactive properties of the tested garlic samples, with the lowest content of polyphenols and antioxidant properties in fresh, unprocessed garlic (6.05 ± 0.07 mg GAE/1 g d.m. and 232.95 ± 4.06 µM TEAC/1 g d.m., respectively), while in garlic subjected to long-term heat treatment, the total polyphenols content and antioxidant potential were two times higher than in the unprocessed garlic. The polyphenol content and antioxidant properties were the highest in the spread garlic (respectively, 15.16 ± 0.08 mg GAE/1 g d.m. and 638.46 ± 3.37 µM TEAC/1 g d.m.) and the lowest in the powdered samples (respectively, 11.02 ± 0.51 mg GAE/1 g d.m. and 541.71 ± 5.22 µM TEAC/1 g d.m.). Obtained black garlic samples gain completely different sensory characteristics determined using instrumental methods. In black garlic and its preparations, the intensity of unpleasant taste and aroma is reduced as a result of the appearance of metabolites during the long-term heat treatment, which in turn determined the specific, delicate sweet–sour taste and pleasant aroma, completely unrelated to the aroma of the unprocessed product. Taking into account the obtained results, it can be stated that black garlic, in the form of cloves, paste and powder, exhibits completely different properties than white garlic.

In Vitro Colonic Fermentation of (Poly)phenols and Organosulfur Compounds of Fresh and Black Garlic

The beneficial properties associated with garlic consumption have been related to the presence of bioactive compounds including (poly)phenols and organosulfur compounds (OSCs). This study aims to assess the effect of in vitro colonic fermentation on fresh and black garlic by determining the transformation of these compounds through ultrahigh-performance liquid chromatography coupled to mass spectrometry with a linear ion trap (uHPLC-LIT-MS). Colonic fermentation had a similar influence on the phenolic content of fresh and black garlic, with total respective decreases of 43.8% and 41.7%. Meanwhile, fermentation resulted in a significant decrease (33%) in OSCs in black garlic. Compounds such as 4-hydroxybenzoic acid, S-allylcysteine (SAC), and methionine sulfoxide were the phenolic compounds and OSCs with the highest concentration in fresh and black garlic after the in vitro fermentation. These compounds, potentially present at the colonic level, might be responsible for the systemic health benefits associated with the consumption of black and fresh garlic.

Novel Nutraceutical Compounds in Alzheimer Prevention

Alzheimer’s disease (AD) incidence is increasing worldwide at an alarming rate. Considering this increase, prevention efforts, stemming from scientific research, health education, and public policies, are critical. Clinical studies evidenced that healthy lifestyles along with natural multitarget and disease-modifying agents have a preventative impact on AD or mitigate symptoms in diagnosed patients. The pathological alterations of AD start 30 years before symptoms, and it is essential to develop the capacity to detect those changes. In this regard, molecular biomarkers that detect early pathological manifestations are helpful. Based on markers data, early preventive interventions could reduce more than 40% of AD cases. Protective actions include exercise, shown to induce neurogenesis, cognitive stimulation, intellectual-social activity, and nutrition among others. Mediterranean diet, preprobiotics, and nutraceuticals containing bioactive molecules with antioxidant and anti-inflammatory properties are relevant. Antiprotein aggregation molecules whose mechanisms were described are important. Anti-inflammatory agents with anti-aggregation properties that help to control cognitive impairment, include quercetin, biocurcumin, rosemarinic acid, and Andean shilajit. Anthocyanidins, e.g., delphinidin, malvidin, and natural flavonoids, are also included. Quercetin and hydroxy-tyrosol are antiaging molecules and could have anti-AD properties. We emphasize the relevance of nutraceuticals as a main actor in the prevention and/or control of dementia and particularly AD.