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Efecto del pH y cloruro de sodio sobre las propiedades funcionales de harina de semillas de lupinus mutabilis "tarwi" variedad criolla Effect of the pH and sodium chloride on the functional properties of flour of lupinus mutabilis "tarwi" seeds variety criolla RESUMENEl objetivo del presente trabajo fue evaluar el efecto del pH (3, 5, 7 and 9) y la concentración de NaCl (0.1, 0.5 a 10 M) de forma independiente sobre las propiedades funcionales de harina entera y desgrasada de Lupinus mutabilis variedad criolla "tarwi". Para ello, las semillas de tarwi se deslupinizaron por el método tradicional (cocción y lixiviado con agua), después se molieron y degrasaron mediante extractor Soxhlet. Las propiedades funcionales de la harina entera de tarwi fueron: absorción de agua de 4,37 g/g sólidos a pH 9, absorción de aceite de 1,18 g/g sólidos, capacidad emulsificante de 35,25% a pH 9, capacidad de hinchamiento de 6,39 ml/g sólidos a pH 9. En tanto, la harina desgrasada de tarwi tuvo una capacidad de absorción de agua de 6,14 g/g sólidos a pH 7, una capacidad de absorción de aceite 1,30 g/g sólido, una capacidad emulsificante de 40,50% a pH 9 y una capacidad de hinchamiento de 6,37 ml/g sólidos a pH 9. En ambos tipos de harina se determinaron bajas propiedades gelificantes y espumantes. Palabras clave: Lupinus mutabilis; absorción; hinchamiento; actividad emulsificante; actividad espumante; estabilidad emulsificante. ABSTRACTThe objective of the present work was to evaluate the effect of pH (3, 5, 7 and 9) and NaCl concentration (0.1, 0.5 and 1 M) independently on the functional properties of tarwi integral and degrased flour (Lupinus mutabilis) criolla variety. For this, the tarwi seeds were desalkaloidized by the traditional method (cooking and leaching with water), then ground and defatted by Soxhlet extractor. The functional properties of the whole tarwi flour were: water absorption of 4.37 g/g solids at pH 9, oil absorption of 1.18 g/g solids, emulsifying capacity of 35.25% at pH 9, capacity of swelling of 6.39 ml/g solids at pH 9. Meanwhile, tarwi defatted flour had a water absorption capacity of 6.14 g/g solids at pH 7, an oil absorption capacity of 1.30 g/g solid, an emulsifying capacity of 40.50% at pH 9 and a swelling capacity of 6.37 ml/g solids at pH 9. Low gelling and foaming properties were determined in both types of flour.

El desarrollo de estrategias que permitan un mayor control de la microbiota intestinal ha incrementado el interés por asociar prebióticos y probióticos, en una relación simbiótica, con el propósito de reducir la presencia de microorganismos patógenos. El objetivo de este estudio fue analizar el efecto simbiótico del extracto de Smallanthus sonchifolius (yacón) y Lactobacillus plantarum sobre el crecimiento de Escherichia coli enteropatógena. Para ello, previamente se analizó la concentración óptima del extracto de yacón para el crecimiento de L. plantarum y su efecto prebiótico. La cinética de crecimiento de ambos microorganismos fue determinada por densidad óptica, conteo por microscopio y células viables en placas. Lactobacillus plantarum presentó un óptimo crecimiento a 15°Brix, alcanzando 109 células/mL; por el contrario, E. coli se mantuvo a bajos niveles poblacionales. La combinación de extracto de yacón y L. plantarum inhibió el crecimiento de E. coli enteropatógena a las 16 h de incubación.

The consumption of chili pepper fruits (CPF) is widespread throughout the world. However, countries without tropical climates can only consume few CPF varieties. The lactic fermentation (LF) of CPF is a good alternative for their preservation and consumption in those regions where they are not cultivated. The main objective of this research was to optimize the fermentation process conditions for a CPF variety (Capsicum frutescens) modifying the Sodium Chloride (NaCl) and glucose concentrations to increase the acidification rate. The Response Surface Methodology was used applying a Central Composite Design to integrate a desirability approach. The growth of the microorganisms responsible for the fermentation process was also evaluated. The addition of NaCl and glucose significantly affected the acidification rate for LF of CPF. The optimum fermentation parameters determined to maximize the acidification rate were 6.25% NaCl and 1.77% glucose concentrations with an acidification rate of 0.113% acidity/day. However, this value was slightly lower than predicted. Lactic acid bacteria and yeasts were the main microorganisms throughout the fermentations.

The objective of this research was the identification and characterization of lactic acid bacteria (LAB) isolated from Peruvian Amazonian fruits. Thirty-seven isolates were obtained from diverse Amazonian fruits. Molecular characterization of the isolates was performed by ARDRA, 16S-23S ITS RFLP and rep-PCR using GTG 5 primers. Identification was carried out by sequencing the 16S rDNA gene. Phenotypic characterization included nutritional, physiological and antimicrobial resistance tests. Molecular characterization by Amplified Ribosomal DNA Restriction Analysis (ARDRA) and 16S-23S ITS RFLP resulted in four restriction profiles while GTG 5 analysis showed 14 banding patterns. Based on the 16S rDNA gene sequence, the isolates were identified as Lactobacillus plantarum (75.7%), Weissella cibaria (13.5%), Lactobacillus brevis (8.1%), and Weissella confusa (2.7%). Phenotypic characterization showed that most of the isolates were homofermentative bacilli, able to ferment glucose, maltose, cellobiose, and fructose and grow in a broad range of temperatures and pH. The isolates were highly susceptible to ampicillin, amoxicillin, clindamycin, chloramphenicol, erythromicyn, penicillin, and tetracycline and showed great resistance to kanamycin, gentamycin, streptomycin, sulfamethoxazole/trimethoprim, and vancomycin. No proteolytic or amylolytic activity was detected. L. plantarum strains produce lactic acid in higher concentrations and Weissella strains produce exopolymers only from sucrose. Molecular methods allowed to accurately identify the LAB isolates from the Peruvian Amazonian fruits, while phenotypic methods provided information about their metabolism, physiology and other characteristics that may be useful in future biotechnological processes. Further research will focus especially on the study of L. plantarum strains.

Efecto del pH y cloruro de sodio sobre las propiedades funcionales de harina de semillas de lupinus mutabilis "tarwi" variedad criolla Effect of the pH and sodium chloride on the functional properties of flour of lupinus mutabilis "tarwi" seeds variety criolla

ResumenLos ajíes son ingredientes básicos de la gastronomía peruana. El ají "Charapita" (Capsicum frutescens) destaca por su amplio uso en la comida amazónica. En la última década, el "boom gastronómico" ha incrementado su demanda por lo que es necesario desarrollar nuevas tecnologías para su conservación de forma sostenible, saludable, sin afectar el medio ambiente. El objetivo del presente trabajo fue analizar la dinámica de las poblaciones microbianas durante la fermentación espontánea (FE) y controlada (FC) del ají "Charapita". Las fermentaciones se realizaron a escala piloto y a temperatura ambiente con ajíes de la ciudad de Iquitos. Para la FC se utilizó la cepa tipo de bacteria ácido láctica (BAL), Lactobacillus plantarum ATCC14917. Las fermentaciones fueron monitoreadas mediante la determinación de azúcares reductores, acidez y pH. Las pruebas microbiológicas fueron contaje al microscopio y viables en medios de cultivos: MRS, YPD, McConkey y Cetrimide para BAL, levaduras, enterobacterias y pseudomonas, respectivamente. Ambas fermentaciones finalizaron a los 47 días, los azúcares reductores estuvieron por debajo de 0,5 g/L, 3,07 -3,11 de pH. Sin embargo la acidez en la FE fue mayor a la FC (1,58% vs. 1,20%). A nivel microbiológico, las BAL y levaduras fueron responsables de la FE. Sin embargo, la cepa inoculada no fue la adecuada para la FC, siendo sustituida por levaduras y enterobacterias. Se concluye que para un mejor control de la fermentación es necesaria la inoculación de microorganismos propios de la fermentación.Palabras clave: fermentación espontánea, fermentación controlada, Capsicum frutescens, BAL, levaduras. AbstractChilies are the main ingredients of the Peruvian gastronomy. Chili "Charapita" (Capsicum frutescens) is very used in amazon food. The last decade, "the gastronomic boom" has increased their demand, so it is necessary to develop new technologies for their preservation sustainably, healthy, without affecting the environment. The aim of the present work was to analyze the microbial population dynamics during Chili "Charapita" fermentation using spontaneous (SF) and controlled (CF) fermentation. Fermentations were conducted at pilot scale and room temperature with chilies from Iquitos city. A lactic acid bacteria (LAB) strain type belonging to Lactobacillus plantarum ATCC 14917 was used in FC. Fermentations were monitored through reducing sugars, acidity and pH determinations. Microbial tests were performed: total cells count by microscopy and microbial growth in culture media. LAB, yeasts, enterobacteriaceae and pseudomonas were recovered in MRS, YPD, McConkey and Cetrimide media, respectively. Both fermentations finalized at 47 days, reducing sugars were below 0.5 g/L and 3.07 -3.11 of pH. However, the acidity in SF was higher than CF (1.58% vs. 1.20%). At microbiological level, LAB and yeasts were microorganisms responsible for SF. However, starter LAB was not suitable for CF. In fact, it was replaced by yeasts and enterobacterias. So, the use of autochthonous microorganisms of the ...