Biodiversity and dairy traits of indigenous milk lactic acid bacteria grown in presence of the main grape polyphenols

Abstract

The present work was developed to select lactic acid bacteria (LAB) to be used as starter cultures in functional cheese production. The indigenous milk LAB populations were isolated from fermented raw ewes’ milks (four bulks) added with 0.5 mg/mL of nine polyphenols commonly found in winery by-products. After 48 h of fermentation, all milks were characterized by an increase of LAB levels of about 3–4 Log cycles. All different colonies were purified and characterized for the main physiological and biochemical traits and then differentiated genetically at strain level and identified. Ten species belonging to the LAB genera Lactobacillus, Streptococcus, Enterococcus, Leuconostoc and Lactococcus were identified. Only Lactococcus lactis and Leuconostoc mesenteroides strains were evaluated for the technological traits including acidification and autolytic kinetics, diacetyl formation, exopolysaccharide production and generation of antimicrobial compounds. A total of four strains (Mise36, Mise94 Mise169 and Mise190) belonging to Lc. lactis displayed potential for production of cheeses containing grape polyphenols.

Monitoring Commercial Starter Culture Development in Presence of Red Grape Pomace Powder to Produce Polyphenol-Enriched Fresh Ovine Cheeses at Industrial Scale Level

“…LAB (Gram positive and catalase negative) were isolated from M17 agar media incubated at 30 • C at the highest dilutions of cell suspensions. After microscopic inspection, all isolates showed coccus-shaped cells organized in short chains, typical of lactococci [40]. As declared by the producer company, RAPD analysis confirmed the presence of two strains (Figure 1) included in the L. lactis freeze-dried starter preparation.…”

Improvement of Caciotta-like cheese nutritional value by means of enrichment with blackcurrant (Ribes nigrum) and Cornelian cherry (Cornus mas)

“…GABA is usually produced in cheese by glutamic acid decarboxylation by LAB (72), and this compound could be a further confirmation of the positive effect of blackcurrant on the LAB activities. The previous study showed that some lactobacilli species, also used as a dairy starter, could be positively affected in their growth by phenolic extracts such as catechins and epicatechins (73), and are very common in blackcurrant. GABA is a bioactive compound with the potential for beneficial effects in humans (72,74), and the GABA increase following the addition of BB to cheeses has to be further investigated through in vitro tests.…”

Polyphenols—Ensured Accessibility from Food to the Human Metabolism by Chemical and Biotechnological Treatments

“…One of the most discussed concerns is for preserving the bioactive compounds of fruits and vegetables and maximizing their potential [ 23 ]. Polyphenols’ main property is related to the fact that they can prevent the oxidative stress affecting and altering the cells [ 5 , 24 ]. Waste and by-products obtained from fruits and vegetables present significant potential sources for polyphenol content, and fermentation is a technology that can help capitalize on them [ 24 , 25 , 26 ].…”

“…Polyphenols of the raw material have been shown to affect the production of lactic acid and interfere with the fermentation, e.g., polyphenols from grapes were shown to inhibit the production of lactic acid in wine production [ 111 ]. Usually, milk and dairy products present an ideal matrix for fermentation due to the amount of bioactive compounds present; although the lactic acid influences the texture, flavour, and nutritional value of the end-product [ 24 ]. The metabolic activity of the starter culture used for the fermentation process, is closely related to the success of the fermentation and to the release of phenolic compounds [ 112 ].…”