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


RESULTS
Italian 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.


CONCLUSIONS
The features of the sourdough fermented legume flours suggested the use for the manufacture of novel functional foods and/or pharmaceuticals preparations.
Department of Soil, Plant and Food Science, University of Bari Aldo Moro, 70126, Bari, Italy. carlogiuseppe.rizzello@uniba.it.
Carlo Giuseppe
CG
Rizzello
Instituto de Investigación en Ciencias de la Alimentación (CIAL, CSIC-UAM CEI UAM + CSIC), Nicolás Cabrera, 9, 28049, Madrid, Spain. b.hernandez@csic.es.
Blanca
B
Hernández-Ledesma
Instituto de Investigación en Ciencias de la Alimentación (CIAL, CSIC-UAM CEI UAM + CSIC), Nicolás Cabrera, 9, 28049, Madrid, Spain. s.fernandez@csic.es.
Samuel
S
Fernández-Tomé
Department of Soil, Plant and Food Science, University of Bari Aldo Moro, 70126, Bari, Italy. josancuriel@gmail.com.
José Antonio
JA
Curiel
Giuliani S.p.a., Milano, Italy. dpinto@giulianipharma.com.
Daniela
D
Pinto
Giuliani S.p.a., Milano, Italy. bmarzani@giulianipharma.com.
Barbara
B
Marzani
Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland. rossana.coda@helsinki.fi.
Rossana
R
Coda
Department of Soil, Plant and Food Science, University of Bari Aldo Moro, 70126, Bari, Italy. marco.gobbetti@uniba.it.
Marco
M
Gobbetti
D000595:Amino Acid Sequence; D019149:Bioreactors; D018938:Caco-2 Cells; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D007887:Fabaceae / Q000378:metabolism*; D000091344:Filaggrin Proteins; D005433:Flour / Q000032:analysis; D005516:Food Microbiology; D006801:Humans; D007381:Intermediate Filament Proteins / Q000235:genetics / Q000378:metabolism; D007558:Italy; D052196:Levilactobacillus brevis / Q000254:growth & development / Q000378:metabolism; D048191:Lactiplantibacillus plantarum / Q000201:enzymology / Q000254:growth & development; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D016415:Sequence Alignment
C000717249:FLG protein, human; D000091344:Filaggrin Proteins; D007381:Intermediate Filament Proteins; D010455:Peptides; D011498:Protein Precursors; D012333:RNA, Messenger; C032253:involucrin