Selenium bio-enrichment of Mediterranean fruit juices through lactic acid fermentation

GAGLIO, RAIMONDO; PESCUMA, MICAELA; MADRID-ALBARRÁN, YOLANDA; FRANCIOSI, ELENA; MOSCHETTI, GIANCARLO; FRANCESCA, NICOLA; MOZZI, FERNANDA; SETTANNI, LUCA

INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY

ELSEVIER SCIENCE BV

Año: 2021

0168-1605

Thiswork was carried out to elaborate selenium (Se) bio-enriched fermented Mediterraneanfruit juices. To this purpose, pomegranate and table red grape juices wereadded with sodium selenite (Na2SeO3) and fermented by Levilactobacillusbrevis CRL 2051 and Fructobacillustropaeoli CRL 2034 individually or combined. To better evaluatethe effect of selenite addition and starter strain inoculums on the totalbacterial community of the fruit juices, fermentation trials were performedwith raw and pasteurized fruit juices. No statistical significant differenceswere observed for total mesophilic microorganisms (TMM) and rod-shaped lacticacid bacteria (LAB) levels among raw and pasteurized juices inoculated with thestarter strains, while significant differences between those juices with andwithout selenite were registered. LAB cocci, Pseudomonadaceaeand yeasts were detected only for the raw juicepreparations. The dominance of L. brevis CRL 2051 and F. tropaeoli CRL 2034 was confirmed by randomly amplifiedpolymorphic DNA (RAPD)-PCR analysis. After fermentation, pH dropped for allinoculated trials and control raw juices. The soluble solid content (SSC)levels of the raw juices were higher than the corresponding pasteurized trials.The thermal treatment affected consistently yellowness of grape juice trialsand redness of pomegranate juices. No microbial Se accumulation was registeredfor pomegranate juices, while F. tropaeoli CRL 2034 accumulated the highest amount of Se (65.5 μg/L) in the grapejuice. For this reason, only trials carried out with raw grape juices wereinvestigated by metagenomics analysis by Illumina MiSeq technology.Non-inoculated grape juices were massively fermented by acetic acid bacteriawhile Fructobacillus andLactobacillus (previousgenus name of Levilactobacillus)represented the highest operational taxonomy units (OTUs) relative abundance %of the trials inoculated with the starter strains as confirmed by thistechnique.