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

Effect of Temperature Conditions on the Physicochemical Quality of Aged Black Garlic

This study investigates the effects of different temperature conditions on the quality of black garlic (BG) during the aging process. Two temperature protocols were employed: gradual heating and cooling (GHC), where the temperature was slowly raised from 45 °C to 77 °C and then lowered to 59 °C at a rate of 1 °C per hour, and rapid heating and cooling (RHC), where the temperature was quickly raised from 45 °C to 85 °C and then lowered to 56 °C at a rate of 1 °C every 30 min. Changes in surface color, hardness, moisture, pH, fructose, total polyphenol content (TPC), and key sulfur compounds such as alliin, S-allylcysteine (SAC), and γ-glutamyl-S-allylcysteine (γ-GSAC) were analyzed. Our findings showed that GHC led to a higher increase in TPC and fructose content by the 15th day compared to RHC. In contrast, RHC retained significantly higher SAC concentrations, approximately 1.7 times that of GHC, by the end of the aging period. Surface color changes, particularly in lightness and redness, were more pronounced under GHC, while RHC demonstrated superior moisture retention. These findings indicate that GHC is better suited for products prioritizing polyphenols and sugars, while RHC is more optimal for SAC-enriched BG. This study provides valuable insights into optimizing BG production for diverse food and medicinal applications through precise temperature modulation.

Effects of aged garlic extract on blood pressure in hypertensive patients: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

There is no consensus based on the existing literature regarding the effect of aged garlic extract (AGE) on blood pressure. The present systematic review and meta-analysis was conducted to synthesize existing data from randomized clinical trials (RCTs) concerning the impact of AGE supplementation on blood pressure in hypertensive patients.

METHODS

We searched English web databases including, PubMed, Scopus, Embase, Web of Science until August 2024. Random-effects meta-analysis was used to pool weighted mean differences (WMD) and 95 % CI for the outcomes.

RESULTS

Overall, nine RCTs with584 participants met inclusion criteria. AGE tea supplementation reduces systolic blood pressure (SBP) (WMD: -4.03; %95CI: -6.87, -1.20; I2: 57.1 %) and diastolic blood pressure (DBP) (WMD: -1.44; 95 % CI= -2.87, -0.02; P = 0.052; I2: 36.8 %; P: 0.105). Moreover, subgroup analysis indicated that higher doses of AGE supplementation in hypertensive patients significantly decreased DBP, and SBP.

CONCLUSION

The results of this study suggest that AGE supplements may be beneficial for improving blood pressure in hypertensive patients, but significant effects are observed only at doses over 1200 mg/day. To confirm these results, well-designed future trials will be needed.

Changes in the Physicochemical Properties, Antioxidant Activity and Metabolite Analysis of Black Elephant Garlic (Allium ampeloprasum L.) during Aging Period

This study investigated the effects of the aging period on the black elephant garlic (Allium ampeloprasum L.) manufacturing process. Black elephant garlic is a processed elephant garlic product prepared by high-temperature and high-humidity treatment for 40 days. The proximate composition (moisture, crude lipid, crude protein, carbohydrate, and ash), minerals, color values, reducing sugars, pH, total polyphenol contents, total flavonoid contents and antioxidant activities of elephant garlic and black elephant garlic were evaluated. The browning intensity of elephant garlic increased with the aging period, but the browning reaction terminated after aging for 30 days, exhibiting the same browning level. Reducing sugars increased over the aging period until 20 days, and then decreased with the aging period, in contrast to the pH, which decreased from 6.47 to 3.68 over the aging period. Antioxidant components, including the total polyphenol and total flavonoid contents of black elephant garlic, increased significantly until day 30 of aging. From the metabolite profiles determined through GC/MS analysis, it was confirmed that primary metabolites related to antioxidant components, such as lactic acid and 5-hydroxymethyl-2-furoic acid, were generated during the aging process of elephant garlic.

Bromatological Analysis and Characterization of Phenolics in Snow Mountain Garlic

The remarkable properties of garlic A. sativum L. have been described, but little is known about Snow mountain garlic. Understanding general aspects of this garlic composition, including the presence of phenolics, will establish its possible use for health or infer which compounds can contribute to improving it. This study aimed to determine the ash content, lipid profile, and characterization of phenolics in Snow mountain garlic. The organic content was obtained by common techniques (oven drying, calcination, Kjeldahl method, etc.). The quantitative analysis of the ashes was made by Inductively Coupled Plasma Emission Spectrometry. The fatty acid profile was determined by Gas Chromatography. The presence of phenolics was determined by foam, Libermann-Burchard, Dragendorff, Salkowski, ferric chloride, vanillin, catechin, Constantinescu, and Shinoda reactions. The total phenolic content was determined via the Folin-Ciocalteu method, and antioxidant activity was determined using the DPPH radical method. The bromatological analysis showed a 51.1% humidity, and the main organic compounds were carbohydrates (46.7%). Ash analysis showed 287.46 g/kg of potassium. The fatty acid profile showed 75.61% of polyunsaturated fatty acid. Phenolics like saponins, alkaloids, triterpenes, tannins, and flavonoids were present. Antioxidant activity was found by radical DPPH of 25.64 (±0.78) µmol TE/1 g dw. Snow mountain garlic shares a composition similar to those found in other garlic.