Abstract: The evolution of aroma-active compounds during the maturation of lizardfish meat and soybean miso was quantified and characterized using the purge-and-trap method for volatile isolation. The results revealed that miso prepared from lizardfish meat and soybeans is the result of alcoholic fermentation rather than acid fermentation. The miso prepared from soybeans matured earlier (60–90 days) than that prepared from lizardfish meat (135 days). The constancy in the volatile lipid-oxidation products, including certain aldehydes and ketones, indicated the oxidative stability of both miso products throughout the fermentation period. The present findings indicated several compounds responsible for miso aroma, including 2-methylpropanal, 3-methylbutanal, 3-methyl-1-butanol, ethyl isobutyrate, 2-methylethyl butanoate, 3-methylethyl buta-noate, ethyl decanoate, 2,3-butanedione, dimethyl trisulfide, methional, and 2-methyl butanoic acid. The formation of aldehyde can be attributed to the decomposition of hydroperoxides and peroxyl radicals, which are supposed to be initial products of oxidized fat. The volatile ketones were most likely the products of lipid and/or amino acid degradation also could possibly be produced from secondary degradation reactions involving diverse substances from the lipid during fermentation and/or may be derived from the Maillard reaction. Formation of the major volatiles in miso products were suggested as a combined effect of fungal metabolism of amino acids, sugars, and lipids, as well as the Maillard reaction during the fer-mentation period. The major difference between miso prepared from lizardfish meat and that from soybeans was the relative abundance of those odor-active compounds that finally characterize the products. Substrate specificmetabolic capacity of A. oryzae and the Maillard reaction were presumed to determine the flavor profile of the end product of miso.Abstract: The evolution of aroma-active compounds during the maturation of lizardfish meat and soybean miso was quantified and characterized using the purge-and-trap method for volatile isolation. The results revealed that miso prepared from lizardfish meat and soybeans is the result of alcoholic fermentation rather than acid fermentation. The miso prepared ...Show More
Abstract: This research was evaluated the antioxidant activity of fish miso, a newly developed fermented fish paste prepared from horse mackerel meat and the fermentation of traditional Japanese koji inoculated with Aspergillusoryzae. The antioxidant activities in different in vitro models, including DPPH, hydroxyl, nitric oxide and carbon-centered radical-scavenging activity (RSA), and reducing power ability (RPA), were investigated during the fermentation period along with 2 different storage conditions. The antioxidant activity of matured fish miso was also evaluated using a linoleic acid oxidation model system by monitoring hydrogen peroxide formation and oxygen absorption. The RSA against all the types of radicals measured by electron spin resonance showed an increase over prolonged fermentation periods and during storage at high temperatures. However, the RPA showed a rapid increase during the early stages of fermentation. The SDS-PAGE profile of fish miso peptides during the early stages of fermentation indicated the occurrence of hydrolysis, suggesting the involvement of low-molecular-weight peptides in the RSA and reducing power of fish miso. Partial purification of these peptides by using an online-HPLC-DPPH flow injection analysis system and further characterization by thin layer chromatography and molecular weight distribution clearly indicated that low-molecular-weight peptides (<500 Da) were potent antioxidants. These data suggest that the antioxidant activity of fish miso could be substantially improved by fermenting Aspergillus (koji) mold. This approach provides a novel strategy to enhance the value of trash fish, such as horse mackerel.Abstract: This research was evaluated the antioxidant activity of fish miso, a newly developed fermented fish paste prepared from horse mackerel meat and the fermentation of traditional Japanese koji inoculated with Aspergillusoryzae. The antioxidant activities in different in vitro models, including DPPH, hydroxyl, nitric oxide and carbon-centered radical-s...Show More
Abstract: Lactic acid bacteria are known for their ability to produce inhibitory substances against unwanted germs involved in food poisoning such as Listeria innocua. Species of lactic acid bacteria can inhibit harmful germs subject of this work. techniques confrontation on solid medium and the effect of the substance on the growth of Listeria innocua were performed. The experience was conducted bacterial antagonism in the solid medium by the method of double layer and method of wells, the whole experience was packaged in a buffered medium in order to eliminate the effect of acidity . 7 strains that isolates gave an antagonistic action against Listeria innocua. The strain of Lactococcus lactis (8b), isolated from raw goat's milk showed an anti-listeria in vitro and was selected because of its ability to inhibit as Staphylococcus aureus. With a diameter of 15mm, the action of proteolytic enzymes, trypsin, chymotrypsin is shown that the substance was protein in nature, the kinetics of growth in milk medium showed that the number of St. aureus after 24 h of incubation was reduced to 7.68 log cfu in mixed culture with strain 8b which was comparable to the control of 9.14 log cfu, which signifies that the survival rate was 3.4%, the phenotypic (biochemical and physiological) and molecular-based ADNr16Ss showed that the strain is Enterococcus faecium, duran, hirae. The sequencing results showed that Leuconostoc mesenteroides and Enterococcus faecium have summers dominant anti-Listeria species in milk samples from Algerian goat. Isolates had the potential of multiple bacteriocin production and do not have some important virulence. Importance and impact of the study: The Enterococci in milk in this region of western Algeria could be partly responsible for the safety of cheese and could be useful for the production of anti-Listeria cultures protection. The purpose of the study: Our study's main objective is the selection ,and study phenotypic and molecular lactic acid bacteria from Lactococcus genus possessing biotech traits such as the production of new inhibitory substance and the study of the interaction of Listeria innocua screw opinion and St. aureus that both methods were used, a traditional approach based on morphological and biochemical studies of different cultural characteristics and a method of direct molecular amplification of bacterial DNA using PCR / RAPD colony on having targeted DNA fragment 16S lactic acid bacteria using the two primers universal: 20F (5'AGAGTTTGATCATGGCTCAG-3 '). 1500R (5'-GGTTACCTTGTTACGACTT-3 ') and two specific primers OPA-3 (5'-AGTCAGCCAC - 3') and OPH 3 (5'-AGACGTCCAC-3 ') (Bioprobe, France).Abstract: Lactic acid bacteria are known for their ability to produce inhibitory substances against unwanted germs involved in food poisoning such as Listeria innocua. Species of lactic acid bacteria can inhibit harmful germs subject of this work. techniques confrontation on solid medium and the effect of the substance on the growth of Listeria innocua were ...Show More