Estefânia Fernandes Garcia

Identification of Lactic Acid Bacteria in Fruit Pulp Processing Byproducts and Potential Probiotic Properties of Selected Lactobacillus Strains

This study aimed to identify lactic acid bacteria (LAB) in byproducts of fruit (Malpighia glabra L., Mangifera indica L., Annona muricata L., and Fragaria vesca L.) pulp processing. Fifty strains of LAB were identified using matrix-assisted laser desorption/ionization–time of flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequence (16S rRNA) analysis. Species belonging to Lactobacillus genus were the predominant LAB in all fruit pulp processing byproducts. The average congruency between the MALDI-TOF MS and 16S rRNA in LAB species identification reached 86%. Isolates of L. plantarum, L. brevis, L. pentosus, L. lactis and L. mesenteroides were identified with 100% congruency. MALDI-TOF MS and 16S rRNA analysis presented 86 and 100% efficiency of LAB species identification, respectively. Further, five selected Lactobacillus strains (L. brevis 59, L. pentosus 129, L. paracasei 108, L. plantarum 49, and L. fermentum 111) were evaluated for desirable probiotic-related properties and growth behavior on two different cultivation media. The exposure to pH 2.0 sharply decreased the counts of the different Lactobacillus strains after a 1 or 2 h incubation, while varied decreases were noted after 3 h of exposure to pH 3.0. Overall, the exposure to pH 5.0 and to bile salts (0.15, 0.30, and 1.00%) did not decrease the counts of the Lactobacillus strains. All tested Lactobacillus strains presented inhibitory activity against Staphylococcus aureus, Salmonella Typhimurium, Salmonella Enteritidis, Listeria monocytogenes and Escherichia coli, and presented variable susceptibility to different antibiotics. The selected Lactobacillus strains presented satisfactory and reproducible growth behavior. In conclusion, MALDI-TOF MS and 16S rRNA analysis revealed high efficiency and congruency for LAB species identification, and the selected Lactobacillus strains may be candidates for further investigation of novel probiotic strains.

Addition of probiotic bacteria in a semi-hard goat cheese (coalho): Survival to simulated gastrointestinal conditions and inhibitory effect against pathogenic bacteria

In this study, the survival of the probiotics Lactobacillus acidophilus (LA-5), Lactobacillus casei subsp. paracasei (L. casei 01) and Bifidobacterium lactis (BB12) incorporated in a Brazilian semi-hard goat cheese (coalho) when exposed to in vitro simulated conditions of digestion was assessed. The inhibitory effects of these probiotic bacteria were also evaluated against Listeria monocytogenes and Staphylococcus aureus in the goat coalho cheese during refrigerated storage. At the end of the in vitro digestion, all of the probiotic tested strains presented decreased (p<0.05) viable cell counts (5.5-6.0logcfu/g) with respect to those determined before exposure to the mouth conditions (7-8logcfu/g). L. casei subsp. paracasei presented inhibition rate of 7.87% and 23.63% against S. aureus on the 14th and 21st day of storage at 10°C, respectively; against L. monocytogenes these values were 12.96 and 32.99%. Positive inhibition rates of B. lactis toward S. aureus were found on the 1st, 14th and 21st days of storage (16.32%, 10.12% and 3.67%, respectively); and against L. monocytogenes only on the 1st day of storage (3.28%). From these results, goat coalho cheese could be an interesting carrier of probiotic strains of L. acidophilus, L. casei subsp. paracasei and B. lactis. Moreover, L. casei subsp. paracasei, could be used as protective culture for delaying the growth of S. aureus and L. monocytogenes in goat coalho cheese.

In Vitro Characterization of Lactobacillus Strains Isolated from Fruit Processing By-Products as Potential Probiotics

Nine wild Lactobacillus strains, namely Lactobacillus plantarum 53, Lactobacillus fermentum 56, L. fermentum 60, Lactobacillus paracasei 106, L. fermentum 250, L. fermentum 263, L. fermentum 139, L. fermentum 141, and L. fermentum 296, isolated from fruit processing by-products were evaluated in vitro for a series of safety, physiological functionality, and technological properties that could enable their use as probiotics. Considering the safety aspects, the resistance to antibiotics varied among the examined strains, and none of the strains presented hemolytic and mucinolytic activity. Regarding the physiological functionality properties, none of the strains were able to deconjugate bile salts; all of them presented low to moderate cell hydrophobicity and were able to autoaggregate, coaggregate with Listeria monocytogenes and Escherichia coli, and antagonize pathogenic bacteria. Exposure to pH 2 sharply decreased the survival of the examined strains after 1- or 2-h exposure; variable decreases were noted after 3-h exposure to pH 3. Overall, exposure to pH 5 and to bile salts (0.15, 0.3, and 1%) did not decrease the strains’ survival. Examined strains presented better ability to survive from the exposure to simulated gastrointestinal conditions in laboratorial media and milk than in grape juice. Considering the technological properties, all the strains were positive for proteolytic activity and EPS and diacetyl production, and most of them had good tolerance to 1–4% NaCl. These results indicate that wild Lactobacillus strains isolated from fruit processing by-products could present performance compatible with probiotic properties and technological features that enable the development of probiotic foods with distinct characteristics.

The performance of five fruit-derived and freeze-dried potentially probiotic Lactobacillus strains in apple, orange, and grape juices: Survival of lactobacilli in fruit juices

BACKGROUND This study assessed the survival of the fruit-derived and freeze-dried L. plantarum 49, L. brevis 59, L. paracasei 108, L. fermentum 111 and L. pentosus 129 strains during frozen storage and when incorporated into apple, orange, and grape juice stored under refrigeration. Physicochemical parameters of juices containing the freeze-dried Lactobacillus strains and the survival of the test strains in the fruit juices during in vitro digestion were also evaluated. RESULTS No decreases in survival rates (log N/log N0) of the freeze-dried cells were observed in up to 1 month of storage. The survival rates of the freeze-dried strains L. plantarum 49 and L. paracasei 108 were > 0.75 in up to 4 months of storage. All freeze-dried strains exhibited survival rates of >0.75 in up to 2 weeks of storage in apple juice; only L. plantarum 49 and L. paracasei 108 showed similar survival rates in orange and grape juices in up to 2 weeks of storage. The contents of the monitored organic acids or sugars during storage varied depending on the added strain and the type of fruit juice. At the end of in vitro digestion, L. brevis 59, L. paracasei 108 and L. fermentum 111 showed survival rates of >0.80 in apple juice. CONCLUSION Apple juice was the best substrate for the survival of the tested freeze-dried Lactobacillus strains over time. L. paracasei 108 and L. plantarum 49 were the strains presenting the best performance for incorporation in potentially probiotic fruit juices.

Effects of Lactobacillus acidophilus LA-3 on physicochemical and sensory parameters of açaí and mango based smoothies and its survival following simulated gastrointestinal conditions

The effects of the incorporation of Lactobacillus acidophilus LA3 (inoculated at 9 log CFU/mL) on physicochemical parameters, contents of sugars and organic acids, phenolic profile and sensory aspects of açaí (AS) and mango based smoothies (MS) during 28 days of refrigerate storage were assessed. The survival of L. acidophilus in AS and MS under simulated human gastrointestinal conditions during storage was also monitored. Counts of L. acidophilus LA-3 were approximately 8.5 log CFU/mL in AS and 7.5 log CFU/mL in MS after 1 day of storage and no changes (p ≥ 0.05) were observed in later evaluated storage time periods. Fruit smoothies (AS or MS) with L. acidophilus LA-3 presented lower (p < 0.05) contents of glucose, fructose and maltose and higher (p < 0.05) contents of lactic and succinic acids compared to those without L. acidophilus LA-3. Phenolic contents increased or decreased (p < 0.05) after 1 day of storage in AS and MS with L. acidophilus LA-3 and did not change (p ≥ 0.05) in AS or MS without L. acidophilus LA-3. The incorporation of L. acidophilus LA-3 increased the acidic flavor and fermented aroma in AS and MS. Viable counts of L. acidophilus LA-3 were approximately 7.5 and 8.5 log CFU/mL in AS and MS, respectively, at the end of in vitro digestion just after the incorporation, as well as on days 14 and 28 of storage. These results show the feasibility of incorporating L. acidophilus LA-3 into AS or MS and suggest these fruit smoothies as matrices for formulation of non-dairy beverages containing potentially probiotic lactobacilli.

Efficacy of the Application of A Coating Composed of Chitosan and Mentha Piperita Essential Oil To Control of Post-Harvest Fungal Pathogens in Tomatoes (Lycopersicum Esculentum)

Ingrid Conceicao Dantas Guerra, Rayssa Julliane de Carvalho, Estefânia Fernandes Garcia, Marta Suely Madruga, Priscila Dinah Lima Oliveira, Maria Lucia da Conceicao, Evandro Leite de Souza. Efficacy of the Application of A Coating Composed of Chitosan and Mentha piperita Essential Oil To Control of Post-Harvest Fungal Pathogens in Tomatoes (Lycopersicum esculentum). In: Anais do 12o Congresso Latinoamericano de Microbiologia e Higiene de Alimentos MICROAL 2014 [= Blucher Food Science Proceedings, num.1, vol.1]. Sao Paulo: Editora Blucher, 2014. DOI 10.5151/foodsci-microal-302 Efficacy of the Application of A Coating Composed of Chitosan and Mentha piperita Essential Oil To Control of Post-Harvest Fungal Pathogens in Tomatoes (Lycopersicum esculentum)