Optimization of the Black Garlic Processing Method and Development of Black Garlic Jam Using High-Pressure Processing

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.

Lacto-fermented garlic handcrafted in the Lower Silesia Region (Poland): Microbial diversity, morpho-textural traits, and volatile compounds

The aim of the present study was to provide a first characterization of lacto-fermented garlic manufactured by local small-scale artisanal producers in the Lower Silesia Region (Poland). The lacto-fermented garlic samples showed high nutritional features in terms of antioxidant activity. A total of 86 compounds, belonging to various chemical classes, were identified by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC/MS). Most of these compounds belonged to six main classes, being sulfur compounds, esters and acetates, oxygenated monoterpenes, monoterpene hydrocarbons, and alcohols. Aldehydes, acids, ketones, furans, and phenols were also identified. In the analyzed samples, counts up to 8 log cfu g-1 were observed for lactic acid bacteria. Metataxonomic analysis revealed the presence of Levilactobacillus, Lactiplantibacillus, Latilactobacillus, Secundilactobacillus, Weissella, Leuconostoc, Lactococcus, Pediococcus, and Lacticaseibacillus among the major taxa. These results were confirmed by the isolation and characterization of viable lactic acid bacteria. Indeed, the presence of the closest relatives to Lacticaseibacillus casei group, Pediococcus parvulus, Levilactobacillus brevis, Levilactobacillus parabrevis, and Lactiplantibacillus plantarum group was observed. A good acidification performance in salty garlic-based medium was observed for all the isolates that, between 8 and 15 days of fermentation, reached pH values comprised between 4 and 3.5, depending on the tested species. Of note, 15 out of the 37 lactic acid bacteria isolates (Levilactobacillus parabrevis, Pediococcus parvulus, Lactiplantibacillus plantarum group, and Lacticaseibacillus casei group) showed the presence of the hdcA gene of Gram-positive bacteria encoding for histidine decarboxylase. Furthermore, for 8 out of the 37 isolates the in-vitro exopolysaccharides production was observed. No isolate showed inhibitory activity against the three Listeria innocua strains used as surrogate for Listeria monocytogenes.

The Browning Properties, Antioxidant Activity, and α-Glucosidase Inhibitory Improvement of Aged Oranges (Citrus sinensis)

Oranges contain many natural active chemicals, organic acids, and polysaccharides. Aging processing is commonly used to modify the color, quality, functional components, and stability of fruits. This study assesses the preparation of aging black oranges using various pre-treatments and solid fermentation. Oranges were aged for six weeks in fresh, non-blanching, blanching, and hot air-assisted aging cycle (AA) groups. The oranges' shrinkage ratio, color difference values, and soluble solids content changed significantly (p < 0.05). Principal component analysis indicated that aging fermentation treatment accelerated glycolysis and increased the ratio of reducing sugars. The enhanced browning can be associated with the oxidation of ascorbic acid (0.66-0.47 mg/g) and the formation of 5-hydroxymethylfurfural (5-HMF) (0.09 mg/g). Furthermore, the presence of free polyphenols led to an increase in the total polyphenol and total flavonoid content. It also had a synergistic effect with 5-HMF in increasing the 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging capacity and ferric ion-reducing antioxidant power (p < 0.05). AA had superior α-glucosidase inhibitory ability increasing from 67.31 to 80.48%. It also reduced the development time by 33%. Therefore, aging technology can enhance the bioactive compounds in oranges and provide a reference for future whole-fruit aging fermentation and health product creation.

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%.

Changes in Physicochemical Characteristics and Antioxidant Activities of Dried Shiitake Mushroom in Dry-Moist-Heat Aging Process

Shiitake mushrooms are prized for their unique flavor and bioactive properties. While there has been extensive research on drying methods, a comprehensive investigation of the effects of drying parameters in the dry-moist-heat system on shiitake quality is still needed. This study aimed to investigate the effects of dry-moist-heat aging on dried shiitake mushrooms comprehensively. Four aging temperatures, specifically 50, 60, 70, and 80 °C, were applied to the mushrooms, maintaining a constant humidity level of 75% RH and aging duration of 20 days. Color analysis revealed a progressive decrease in measured values as aging temperature increased, indicating noticeable changes in visual characteristics. Regarding amino acid composition, glutamic acid was found to be the predominant amino acid in shiitake mushrooms in the range of 90.29-467.42 mg/100 g. However, aging led to a reduction in overall amino acid content, with higher aging temperatures resulting in greater decline. Similarly, the equivalent umami content (EUC) also decreased (from 123.99 to 7.12 g MSG/100 g) with the increase in aging temperatures up to 80 °C, suggesting a decline in the overall umami taste sensation. Interestingly, despite the reduction in amino acid levels and umami content, the aging process positively impacted the phenolic compounds and the antioxidant activity of dried shiitake mushrooms. The antioxidative abilities of all aged mushroom extracts for DPPH, ABTS, and FRAP ranged from 65.01 to 81.39 µg TE/mL, 87.04 to 258.33 µg GAE/mL, and 184.50 to 287.68 µg FeSO₄/mL, respectively. The utilization of aged temperature at 60 °C for 20 days with controlled relative humidity (~75%) should be a suitable aging condition of this edible mushroom with both antioxidant and umami qualities. Nevertheless, the control sample demonstrated higher levels of amino acid content and EUC compared to the aged samples. Conversely, the aged samples exhibited higher polyphenol content and greater antioxidant activity. Depending on specific requirements, these powders can be used in food formulation as flavor enhancers for control samples or as enriching agents for polyphenols and antioxidant activity in matured samples. Therefore, all of the powders obtained have potential applications in the field of nutrition.