Italian legumes: effect of sourdough fermentation on lunasin-like polypeptides

Abstract

BackgroundThere is an increasing interest toward the use of legumes in food industry, mainly due to the quality of their protein fraction. Many legumes are cultivated and consumed around the world, but few data is available regarding the chemical or technological characteristics, and especially on their suitability to be fermented. Nevertheless, sourdough fermentation with selected lactic acid bacteria has been recognized as the most efficient tool to improve some nutritional and functional properties. This study investigated the presence of lunasin-like polypeptides in nineteen traditional Italian legumes, exploiting the potential of the fermentation with selected lactic acid bacteria to increase the native concentration. An integrated approach based on chemical, immunological and ex vivo (human adenocarcinoma Caco-2 cell cultures) analyses was used to show the physiological potential of the lunasin-like polypeptides.ResultsItalian legume varieties, belonging to Phaseulus vulgaris, Cicer arietinum, Lathyrus sativus, Lens culinaris and Pisum sativum species, were milled and flours were chemically characterized and subjected to sourdough fermentation with selected Lactobacillus plantarum C48 and Lactobacillus brevis AM7, expressing different peptidase activities. Extracts from legume doughs (unfermented) and sourdoughs were subjected to western blot analysis, using an anti-lunasin primary antibody. Despite the absence of lunasin, different immunoreactive polypeptide bands were found. The number and the intensity of lunasin-like polypeptides increased during sourdough fermentation, as the consequence of the proteolysis of the native proteins carried out by the selected lactic acid bacteria. A marked inhibitory effect on the proliferation of human adenocarcinoma Caco-2 cells was observed using extracts from legume sourdoughs. In particular, sourdoughs from Fagiolo di Lamon, Cece dell’Alta Valle di Misa, and Pisello riccio di Sannicola flours were the most active, showing a decrease of Caco-2 cells viability up to 70 %. The over-expression of Caco-2 filaggrin and involucrin genes was also induced. Nine lunasin-like polypeptides, having similarity to lunasin, were identified.ConclusionsThe features of the sourdough fermented legume flours suggested the use for the manufacture of novel functional foods and/or pharmaceuticals preparations.

Updating the research on the chemopreventive and therapeutic role of the peptide lunasin

“…However, other proteins with higher molecular weight were recognised by soybean lunasin antibodies providing the hypothesis that lunasin‐like peptides could be released from precursor proteins by the action of proteases from gastrointestinal or microbial origin. This hypothesis is in line with the study by Rizzello and co‐workers who investigated the presence of lunasin‐like polypeptides in nineteen traditional Italian legumes after sourdough fermentation with Lactobacillus plantarum C48 and Lactobacillus brevis AM7, expressing different peptidases . These authors confirmed the absence of lunasin in legume flours although different lunasin‐like polypeptides were found in bean and lentil varieties.…”

“…This hypothesis is in line with the study by Rizzello and co-workers who investigated the presence of lunasin-like polypeptides in nineteen traditional Italian legumes after sourdough fermentation with Lactobacillus plantarum C48 and Lactobacillus brevis AM7, expressing different peptidases. 28 These authors confirmed the absence of lunasin in legume flours although different lunasin-like polypeptides were found in bean and lentil varieties. After lactic acid fermentation, legume sourdoughs showed increased number and intensities of lunasin-like polypeptides, suggesting that endogenous legume proteases and microbial peptidases were responsible for the release of lunasin-like fragments.…”

Identification and biotechnological characterization of lactic acid bacteria isolated from chickpea sourdough in northwestern Argentina

“…Different food processing strategies such as soaking, dehulling, germination and long-time cooking are commonly applied to inactivate ANF, however some residual activity could remain and bioactivity of other phytochemicals could be affected (Patterson, Curran, & Der, 2017). Fermentation has proven to be an effective option for processing legumes that improve their nutritional and nutraceutical properties by the removal of ANF and the release of bioactive compounds (Coda et al, 2015;Curiel, et al, 2015;Chandra-Hioe, Wong, & Arcot;Gan, Shah, Wang, Lui, & Corke, 2016;Rizzello, Calasso, Campanella, De Angelis, & Gobbetti, 2014;Sáez, Hébert, Saavedra, & Zárate, 2017).…”

“…Fermentation can be spontaneously produced by endogenous microbiota of legumes (Gan et al, 2016;Rizzelo et al, 2014) or controlled by inoculation of starter cultures (Coda et al, 2015;Curiel et al, 2015;Gan et al, 2016;Chandra-Hioe et al, 2016;Sáez et al, 2017). Few studies have assessed the natural microbiota of unfermented and spontaneous fermented chickpea seeds and flours worldwide.…”

Effects of Fermented Edible Seeds and Their Products on Human Health: Bioactive Components and Bioactivities

“…Besides, fermented edible seeds and their products also contain other bioactive peptides, such as taste‐active peptides (Zhao and Gänzle ) and lunasin‐like peptides (Rizzello and others ), which may possess anti‐cancer effects (Rizzello and others ). In general, fermented edible seeds and their products are good sources of various bioactive peptides.…”