In Vitro Evaluation of the Probiotic and Safety Properties of Bacteriocinogenic and Non-Bacteriocinogenic Lactic Acid Bacteria from the Intestines of Nile Tilapia and Common Carp for Their Use as Probiotics in Aquaculture.

In this study, seven bacteriocinogenic and non-bacteriocinogenic LAB strains previously isolated from the intestines of Nile tilapia and common carp and that showed potent antibacterial activity against host-derived and non-host-derived fish pathogens were assayed for their probiotic and safety properties so as to select promising candidates for in vivo application as probiotic in aquaculture. All the strains were investigated for acid and bile tolerances, transit tolerance in simulated gastrointestinal conditions, for cell surface characteristics including hydrophobicity, co-aggregation and auto-aggregation, and for bile salt hydrolase activity. Moreover, haemolytic, gelatinase and biogenic amine-producing abilities were investigated for safety assessment. The strains were found to be tolerant at low pH (two strains at pH 2.0 and all the strains at pH 3.0). All of them could also survive in the presence of bile salts (0.3% oxgall) and in simulated gastric and intestinal juices conditions. Besides, three of them were found to harbour the gtf gene involved in pH and bile salt survival. The strains also showed remarkable cell surface characteristics, and 57.14% exhibited the ability to deconjugate bile salts. When assayed for their safety properties, the strains prove to be free from haemolytic activity, gelatinase activity and they could neither produce biogenic amines nor harbour the hdc gene. They did not also show antibiotic resistance, thus confirming to be safe for application as probiotics. Among them, Lactobacillus brevis 1BT and Lactobacillus plantarum 1KMT exhibited the best probiotic potentials, making them the most promising candidates.

Valorization of Pomace Powder Obtained from Native Mexican Apple (Malus domestica var. rayada): Chemical, Techno-functional and Antioxidant Properties.

The aims of the work were to determine the chemical, techno-functional and antioxidant properties of native Mexican apple pomace powder (MAPP) obtained from cider industry. The proximate composition and the total, insoluble and soluble dietary fibre content were determined, as well as the water holding (WHC), oil holding (OHC), swelling (SWC) capacities and the polyphenolic profile. For antioxidant activity, three different test systems were used (DPPH, FIC and FRAP). The total, insoluble and soluble dietary fiber content of MAPP was 70.91, 48.43 and 22.48 g/100 g, respectively. MAPP had a WHC, OHC and SWC of 4.2 g water/g sample, 1.69 g oil/g sample and 3.2 mL/g sample, respectively. Polyphenolic profile showed 10 flavonoid compounds identified mainly quercetin glycosides. MAPP showed good antioxidant activity with high correlation between total phenolic compounds and antioxidant capacity. The results obtained showed that MAPP could be considered a good source of bioactive compounds with significant antioxidant activity.