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

Abstract

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.

Quality Assessment of Minced Poultry Products Including Black Fermented Garlic

“…As reported by Kim et al [ 7 ], the compounds in black garlic have a destructive effect on bacteria (among others, on Staphylococcus , Streptococcus , Salmonella , Escherichia , Klebsiella , Proteus , Helicobacter , Mycobacterium , and Clostridium ), protozoa ( Entamoeba histolytica ) and fungi ( Candida albicans , Saccharomyces cerevisiae , Pichia anomala , Hanseniaspora valbyensis , and Aspergillus niger ). Of particular importance is allicin, which penetrates into the cell and interacts with cytoplasmic components and enzymes; this compound also blocks lipid and RNA synthesis in bacteria [ 6 , 13 ].…”

“…Furthermore, the Maillard reaction, which occurs during fermentation, increases the concentration of total phenolic acid, flavonoids, 5-hydroxymethylfurfural, melanoidins and thiosulfinates in black garlic [ 2 , 3 , 9 , 11 ]. The fermentation process leads to a decreased pH of the garlic as well as decreased moisture content, thus increasing its shelf life [ 12 , 13 , 14 ]. Fermentation not only affects the basic composition or physicochemical properties of garlic, but also increases the concentration of biologically active compounds [ 4 , 15 , 16 , 17 ].…”

Zein electrospun fibers with red onion extract (Allium cepa L.): Bioactive compounds, thermal stability, hydrophilicity, and antioxidant activity

“…The compounds 2-octanone and 2decanone were also identi ed (~ 0.01 mg/mL). In black garlic (Allium sativum L.), the compound 2octanone has already been identi ed by Najman et al (2022), who reported that this volatile could be detected due to aging. The authors attributed that this substance can contribute to the roasted, burnt, caramelized, green, and fruity aroma.…”

Electrospun nanofibers based on zein and red onion bulb extract (Allium cepa, L.): Volatile compounds, hydrophilicity, and antioxidant activity

“…The VOCs 2-octanone and 2-decanone were also identified (∼0.01 mg/mL). In black garlic (Allium sativum L.), 2-octanone has already been identified by Najman et al (2022), who reported that its presence could be due to its aging process. The authors stated that this substance can contribute to the roasted, burnt, caramelized, green, and fruity aroma.…”