RESUMEN
In the current trend where plant-based foods are preferred over animal-based foods, pulses represent an alternative source of protein but also of bioactive peptides (BPs). We investigated the pattern of protein hydrolysis during fermentation of red lentils protein isolate (RLPI) with various lactic acid bacteria and yeast strains. Hanseniaspora uvarum SY1 and Fructilactobacillus sanfranciscensis E10 were the most proteolytic microorganisms. H. uvarum SY1 led to the highest antiradical, angiotensin-converting enzyme-inhibitory and antifungal activities, as found in low molecular weight water soluble extracts (LMW-WSE). The 2039 peptide sequences identified by LMW-WSE were screened using BIOPEP UWM database, and 36 sequences matched with known BPs. Fermentation of RLPI by lactic acid bacteria and yeasts generated 12 peptides undetected in raw RLPI. Besides, H. uvarum SY1 led to the highest abundance (peak areas) of BPs, in particular with antioxidant and ACE-inhibitory activities. The amino acid sequences LVR and LVL, identified in the fermented RLPI, represent novel findings, as they were detected for the first time in substrates subjected to microbial fermentation. KVI, another BP highly characteristic of RLPI-SY1, was previously observed only in dried bonito. 44 novel potential BPs, worthy of further characterization, were correlated with antifungal activity.
Asunto(s)
Lactobacillales , Lens (Planta) , Animales , Lactobacillales/metabolismo , Lens (Planta)/metabolismo , Inhibidores de la Enzima Convertidora de Angiotensina/química , Inhibidores de la Enzima Convertidora de Angiotensina/metabolismo , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Antifúngicos , Filogenia , Péptidos/farmacología , Levaduras/metabolismo , FermentaciónRESUMEN
Our study investigated the potential of Annona squamosa (L.) fruit as a reservoir of yeasts and lactic acid bacteria having biotechnological implications, and phenolics capable of modifying the ecology of microbial consortia. Only a single species of lactic acid bacteria (Enterococcus faecalis) was identified, while Annona fruit seemed to be a preferred niche for yeasts (Saccharomyces cerevisiae, Hanseniaspora uvarum), which were differentially distributed in the fruit. In order to identify ecological implications for inherent phenolics, the antimicrobial potential of water- and methanol/water-soluble extracts from peel and pulp was studied. Pulp extracts did not show any antimicrobial activity against the microbial indicators, while some Gram-positive bacteria (Staphylococcus aureus, Staphylococcus saprophyticus, Listeria monocytogenes, Bacillus megaterium) were susceptible to peel extracts. Among lactic acid bacteria used as indicators, only Lactococcus lactis and Weissella cibaria were inhibited. The chemical profiling of methanol/water-soluble phenolics from Annona peel reported a full panel of 41 phenolics, mainly procyanidins and catechin derivatives. The antimicrobial activity was associated to specific compounds (procyanidin dimer type B [isomer 1], rutin [isomer 2], catechin diglucopyranoside), in addition to unidentified catechin derivatives. E. faecalis, which was detected in the epiphytic microbiota, was well adapted to the phenolics from the peel. Peel phenolics had a growth-promoting effect toward the autochthonous yeasts S. cerevisiae and H. uvarum.
Asunto(s)
Annona , Antiinfecciosos , Catequina , Malus , Frutas/microbiología , Catequina/análisis , Annona/química , Annona/microbiología , Metanol/análisis , Saccharomyces cerevisiae , Extractos Vegetales/farmacología , Extractos Vegetales/química , Antiinfecciosos/farmacología , Antiinfecciosos/análisis , Agua/análisis , Azúcares/análisisRESUMEN
Bee-collected pollen (BCP) is currently receiving increasing attention as a dietary supplement for humans. In order to increase the accessibility of nutrients for intestinal absorption, several biotechnological solutions have been proposed for BCP processing, with fermentation as one of the most attractive. The present study used an integrated metabolomic approach to investigate how the use of starter cultures may affect the volatilome and the profile of bioaccessible phenolics of fermented BCP. BCP fermented with selected microbial starters (Started-BCP) was compared to spontaneously fermented BCP (Unstarted-BCP) and to unprocessed raw BCP (Raw-BCP). Fermentation significantly increased the amount of volatile compounds (VOC) in both Unstarted- and Started-BCP, as well as modifying the relative proportions among the chemical groups. Volatile free fatty acids were the predominant VOC in Unstarted-BCP. Started-BCP was differentiated by the highest levels of esters and alcohols, although volatile free fatty acids were always prevailing. The profile of the VOC was dependent on the type of fermentation, which was attributable to the selected Apilactobacillus kunkeei and Hanseniaspora uvarum strains used as starters, or to the variety of yeasts and bacteria naturally associated to the BCP. Started-BCP and, to a lesser extent, Unstarted-BCP resulted in increased bioaccessible phenolics, which included microbial derivatives of phenolic acids metabolism.
RESUMEN
Structure of lactic acid bacteria biota in ivy flowers, fresh bee-collected pollen (BCP), hive-stored bee bread, and honeybee gastrointestinal tract was investigated. Although a large microbial diversity characterized flowers and fresh BCP, most of lactic acid bacteria species disappeared throughout the bee bread maturation, giving way to Lactobacillus kunkeei and Fructobacillus fructosus to dominate long stored bee bread and honeybee crop. Adaptation of lactic acid bacteria was mainly related to species-specific, and, more in deep, to strain-specific features. Bee bread preservation seemed related to bacteria metabolites, produced especially by some L. kunkeei strains, which likely gave to lactic acid bacteria the capacity to outcompete other microbial groups. A protocol to ferment BCP was successfully set up, which included the mixed inoculum of selected L. kunkeei strains and Hanseniaspora uvarum AN8Y27B, almost emulating the spontaneous fermentation of bee bread. The strict relationship between lactic acid bacteria and yeasts during bee bread maturation was highlighted. The use of the selected starters increased the digestibility and bioavailability of nutrients and bioactive compounds naturally occurring in BCP. Our biotechnological protocol ensured a product microbiologically stable and safe. Conversely, raw BCP was more exposed to the uncontrolled growth of yeasts, moulds, and other bacterial groups.
Asunto(s)
Abejas/microbiología , Microbiología de Alimentos , Polen/metabolismo , Polen/microbiología , Própolis/metabolismo , Animales , Antiinfecciosos , Fermentación , Flores/microbiología , Tracto Gastrointestinal/microbiología , Hanseniaspora/metabolismo , Hedera , Lactobacillales/clasificación , Lactobacillales/crecimiento & desarrollo , Lactobacillales/aislamiento & purificación , Lactobacillales/metabolismo , Lactobacillus/clasificación , Lactobacillus/crecimiento & desarrollo , Lactobacillus/aislamiento & purificación , Lactobacillus/metabolismo , Interacciones Microbianas , Microbiota , Polen/química , Especificidad de la EspecieRESUMEN
Freeze-dried cell-free extracts (CFE) from Lactobacillus casei LC01, Weissella cibaria 1XF5, Hafnia alvei Moller ATCC 51815, and Debaryomyces hansenii LCF-558 were used as sources of enzyme activities for conditioning the ripening of ewe milk cheese. Compared with control cheese (CC), CFE did not affect the gross composition and the growth of the main microbial groups of the cheeses. As shown through urea-PAGE electrophoresis of the pH 4.6-soluble nitrogen fraction and the analysis of free AA, the secondary proteolysis of the cheeses with CFE added was markedly differed from that of the CC. Compared with CC, several enzyme activities were higher in the water-soluble extracts from cheeses made with CFE. In agreement, the levels of 49 volatile compounds significantly differentiated CC from the cheeses made with CFE. The level of some alcohols, ketones, sulfur compounds, and furans were the lowest in the CC, whereas most aldehydes were the highest. Each CFE seemed to affect a specific class of chemical compounds (e.g., the CFE from H. alvei ATCC 51815 mainly influenced the synthesis of sulfur compounds). Apart from the microbial source used, the cheeses with the addition of CFE showed higher score for acceptability than the control cheese. Cheese ripening was accelerated or conditioned using CFE as sources of tailored enzyme activities.