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The objective of this study was to evaluate the probiotic properties of Lactobacillus casei and Lactobacillus fermentum strains, as well as to select novel and safe strains for future development of functional fermented products. The in vitro auto-aggregation, co-aggregation, hydrophobicity, β-galactosidase production, survival to gastrointestinal tract (GIT), and antibiotic susceptibility were evaluated. The selected strains were additionally tested by the presence of genes encoding adhesion, aggregation and colonization, virulence factors, antibiotic resistance, and biogenic amine production, followed by the evaluation of acidifying kinetic parameters in milk, and survival of the strains under simulated GIT conditions during refrigerated storage of fermented milk. Most strains of both species showed high auto-aggregation; some strains showed co-aggregation ability with other lactic acid bacteria (LAB) and/or pathogens, and both species showed low hydrophobicity values. Seven L. casei and six L. fermentum strains produced β-galactosidase enzymes, and ten strains survived well the simulation of the GIT stressful conditions evaluated in vitro. All strains were resistant to vancomycin, and almost all the strains were resistant to kanamycin. L. casei SJRP38 and L. fermentum SJRP43 were distinguished among the other LAB strains by their higher probiotic potential. L. fermentum SJRP43 presented fewer genes related to virulence factors and antibiotic resistance and needed more time to reach the maximum acidification rate (V). The other kinetic parameters were similar. Both strains survived well (> 8 log CFU/mL) to the GIT-simulated conditions when incorporated in fermented milk. Therefore, these strains presented promising properties for further applications in fermented functional products.

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In this work, we investigated the effect of supplementing fermented milk with quinoa flour as an option to increase probiotic activity during fermented milk production and storage. Fermented milk products were produced with increasing concentrations of quinoa flour (0, 1, 2, or 3g/100g) and submitted to the following analyses at 1, 14, and 28 d of refrigerated storage: postacidification, bacterial viability, resistance of probiotics to simulated gastrointestinal (GI) conditions, and adhesion of probiotics to Caco-2 cells in vitro. The kinetics of acidification were measured during the fermentation process. The time to reach maximum acidification rate, time to reach pH 5.0, and time to reach pH 4.6 (end of fermentation) were similar for all treatments. Adding quinoa flour had no effect on fermentation time; however, it did contribute to postacidification of the fermented milk during storage. Quinoa flour did not affect counts of Bifidobacterium animalis ssp. lactis BB-12 or Lactobacillus acidophilus La-5 during storage, it did not protect the probiotic strains during simulated GI transit, and it did not have a positive effect on the adhesion of probiotic bacteria to Caco-2 cells in vitro. Additionally, the adhesion of strains to Caco-2 cells decreased during refrigerated storage of fermented milk. Although the addition of up to 3% quinoa flour had a neutral effect on probiotic activity, its incorporation to fermented milk can be recommended because it is an ingredient with high nutritive value, which may increase the appeal of the product to consumers.

This study examined the antioxidant activity of lyophilized rosemary extract added to soybean oil, subjected to thermoxidation conditions and also its synergistic effect with the synthetic antioxidant tertiary butylhydroquinone (TBHQ). Soybean oil samples with no antioxidant added (SO), 3,000 mg/kg rosemary extract (RE), 50 mg/kg TBHQ (TBHQ), and a mixture of those two antioxidants (RE + TBHQ) were heated to 180C for 20 h. After 0, 10 and 20 h, the oxidative stability, total polar compounds, tocopherol content and fatty acid profile were determined. The addition of rosemary extract increased oxidative stability and resulted in a lower formation of total polar compounds and a higher retention of tocopherols. The RE treatment showed the highest amount of polyunsaturated fatty acids after 20 h. There was not any synergy between TBHQ and rosemary extract in preventing oxidation of soybean oil. Rosemary extract showed a higher antioxidant potential when compared with TBHQ. PRACTICAL APPLICATIONS Antioxidants are important ingredients in food processing because they have the capacity to protect foods, containing oils and fats, from damage caused by free radicals and reactive oxygen species. Synthetic antioxidants are widely used in the food industry; however, their utilization has been questioned because of toxicity. Therefore, there is a growing interest in the use of natural antioxidants to reduce or replace the synthetic antioxidants. Several species are used in cooking, medicine and by the pharmaceutical industry, standing out the rosemary. Being rich in compounds with high antioxidant activity, the rosemary extract can be used to replace synthetic antioxidants used in vegetable oils.

This study aimed at characterizing guava, orange and passion fruit by-products and investigating the effect of adding these fruit by-products to probiotic fermented goat milk and cereal-based fermented products. Fruit byproducts showed total fiber content, phenolic compounds and antioxidant activity varying from, respectively, 58.20-89.80%, 253.14-420.89 mg GAE/100 g, and 11.38-17.37 μmol TE/g. Most carotenoids were represented by β-carotene, which ranged from 7.91 to 56.07 μg/g. The presence of fruit by-products did not affect the fermentation time of fermented oat beverage and fermented goat milk; however, a significant increase (ranging from 0.28 to 0.91 h) in fermentation time of fermented rice beverages was observed after the addition of byproducts. Fruit by-products also resulted in an increase in acidification throughout storage; however, they did not affect the counts of probiotic bacteria. A decrease in probiotic survival during in vitro gastrointestinal simulation was observed in all treatments. Nonetheless, the presence of orange and passion fruit by-products enhanced the resistance of the probiotics to simulated gastrointestinal conditions and resulted in population 2 log CFU/mL higher than the control treatment. Fruit by-products can be considered relevant sources of bioactive compounds useful in raising the functional attributes of probiotic fermented products.