Agroindustrial by-products derived from fruit processing are an important source of biocompounds that can be used as functional food ingredients. The objective of this work was to evaluate cactus pear and pineapple peel flours as an alternative carbon source during fermentation using bacteria with probiotic potential. The total fibre content of both flours was over 60%, with total soluble carbohydrate content around 20%, indicating a good carbon source for lactic acid bacteria. Kinetic parameters indicate that peel flours are a suitable carbon source because the lactic acid bacteria grow (mean growth rate constant, k, values close to glucose, 1.52 h) and acidify the culture media (maximum acidification rate, V max , approximately 1.60 pH 9 10 À3 min À1 ). There was no difference in prebiotic potential or prebiotic activity score for both the peel flours. Pediococcus pentosaceus performs better during fermentation. In this respect, cactus pear and pineapple peel flours can be used as functional ingredients due to their fermentable properties.Fruit peels as functional ingredients J. Diaz-Vela et al. Fruit peels as functional ingredients J. Diaz-Vela et al. Strain Carbon source pH final N (Log CFU mL À1 ) Pediococcus pentosaceus UAM22 Glucose (control) 4.39 AE 0.28 C,a 9.52 AE 0.25 A,a Cactus pear flour 5.81 AE 0.35 C,a 9.65 AE 0.25 A,a Pineapple flour 4.89 AE 0.42 C,a 9.56 AE 0.31 A,a Aerococcus viridans UAM21 Glucose (control) 6.12 AE 0.63 B,a 9.22 AE 0.24 B,a Cactus pear flour 5.64 AE 0.85 B,a 8.73 AE 0.25 B,a Pineapple flour 7.88 AE 0.21 B,a 9.33 AE 0.13 B,a Lactobacillus rhamnosus GG Glucose (control) 5.82 AE 0.57 C,a 9.24 AE 0.27 B,a Cactus pear flour 4.63 AE 0.85 C,a 8.77 AE 0.15 B,a Pineapple flour 5.15 AE 0.56 C,a 9.38 AE 0.26 B,a Escherichia coli K12 Glucose (control) 5.91 AE 0.21 A,a 8.46 AE 0.11 C,a Cactus pear flour 6.29 AE 0.14 A,a 8.63 AE 0.24 C,a Pineapple flour 6.68 AE 0.42 A,a 8.21 AE 0.22 C,a A, B, C, D means with same letter in same column are not significantly different (P > 0.05) for strain type. a, b means with same letter in same column are not significantly different (P > 0.05) for carbon source. Pediococcus pentosaceus UAM22 Cactus pear flour 0.33 AE 0.03 A,a Pineapple flour 0.32 AE 0.01 A,a Aerococcus viridans UAM21 Cactus pear flour À0.03 AE 0.02 C,a Pineapple flour 0.09 AE 0.02 C,a Lactobacillus rhamnosus GG Cactus pear flour 0.19 AE 0.01 B,a Pineapple flour 0.21 AE 0.02 B,aA, B, C means with same letter in same column are not significantly different (P > 0.05) for strain type. a, b means with same letter in same column are not significantly different (P > 0.05) for carbon source.Fruit peels as functional ingredients J. Diaz-Vela et al.

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.

The present study aimed to evaluate the bacterial load of water, Nile Tilapia and common Carp intestines from earthen ponds, isolate lactic acid bacteria (LAB) and assess their antimicrobial activity against fish spoilage and pathogenic bacteria. Following enumeration and isolation of microorganisms the antimicrobial activity of the LAB isolates was evaluated. Taxonomic identification of selected antagonistic LAB strains was assessed, followed by partial characterisation of their antimicrobial metabolites. Results showed that high counts (>4 log c.f.u ml or 8 log c.f.u g) of total aerobic bacteria were recorded in pond waters and fish intestines. The microbiota were also found to be dominated by Salmonella spp., Vibrio spp., Staphylococcus spp. and Escherichia coli. LAB isolates (5.60%) exhibited potent direct and extracellular antimicrobial activity against the host-derived and non host-derived spoilage and pathogenic bacteria. These antagonistic isolates were identified and Lactococcus lactis subsp. lactis was found as the predominant (42.85%) specie. The strains displayed the ability to produce lactic, acetic, butyric, propionic and valeric acids. Bacteriocin-like inhibitory substances with activity against Gram-positive and Gram-negative (Vibrio spp. and Pseudomonas aeruginosa) bacteria were produced by three L. lactis subsp. lactis strains. In this study, the LAB from the microbiota of fish and pond water showed potent antimicrobial activity against fish spoilage or pathogenic bacteria from the same host or ecological niche. The studied Cameroonian aquatic niche is an ideal source of antagonistic LAB that could be appropriate as new fish biopreservatives or disease control agents in aquaculture under tropical conditions in particular or worldwide in general.

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.

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