Red grape Nero d’Avola cultivar grape pomace powder (GPP) was applied during fresh ovine cheese production in order to increase polyphenol content. Before cheeses were produced, the bacteria of a freeze-dried commercial starter culture were isolated and tested in vitro against GPP. Two dominant strains, both resistant to GPP, were identified. Thestarter culture was inoculated in pasteurized ewe’s milk and the curd was divided into two bulks, one added with 1% (w/w) GPP and another one GPP-free. GPP did not influence the starter culture development, since lactic acid bacteria (LAB) counts were 109 CFU/g in both cheeses at 30 d. To exclude the interference of indigenous LAB, the pasteurized milk was analyzed, and several colonies of presumptive LAB were isolated, purified and typed. Four strains were allotted into Enterococcus and Lacticaseibacillus genera. The direct comparison of the polymorphic profiles of cheese bacteria evidenced the dominance of the starter culture over milk LAB. The addition of GPP increased cheese total phenolic compounds by 0.42 g GAE/kg. Sensory evaluation indicated that GPP-enriched cheese was well appreciated by the judges, providing evidence that GPP is a suitable substrate to increase the availability of total phenolic content in fresh ovine cheese.
The main goal of this research was to characterize the bacterial diversity of wooden boards used for aging traditional Sicilian cheeses and to evaluate whether pathogenic bacteria are associated with these surfaces. Eighteen cheese dairy factories producing three traditional cheese typologies (PDO Pecorino Siciliano, PDO Piacentinu Ennese and Caciocavallo Palermitano) were selected within Sicily region. The wooden shelf surfaces were sampled by a destructive method to detach wood splinters as well as by a non-destructive brushing to collect microbial cells. Scanning electron microscopy showed the presence of almost continuous bacterial formations on the majority of the shelves analysed. Yeasts and fungal hyphae were also visualized, indicating a complexity of the plank communities. The amplicon library of the 16S rRNA gene V3-V4 region was pair-end sequenced using the Illumina MiSeq system allowing the identification of 14 phyla, 32 classes, 52 orders, 93 families and 137 genera. Staphylococcus equorum was identified from all wooden surfaces with a maximum abundance of 64.75%. Among cheese surface ripening bacteria, Brevibacterium and Corynebacterium were detected in almost all samples. Several halophilic ( Halomonas , Tetragenococcus halophilus , Chromohalobacter, Salimicrobium , Marinococcus , Salegentibacter , Haererehalobacter , Marinobacter and Idiomarinaceae) and moderately halophilic ( Salinicoccus , Psychrobacter and Salinisphaera ) bacteria were frequently identified. Lactic acid bacteria (LAB) were present at low percentages with the genera Leuconostoc , Lactococcus , Lactobacillus , Pediococcus and Streptococcus . The levels of wooden shelf viable microorganisms ranged between 2.4 and 7.8 log CFU/cm 2 . In some cases, LAB were counted at very high levels (8.2 log CFU/cm 2 ). Members of Enterobacteriaceae family were detected in a viable state only for six samples. Coagulase positive staphylococci, Salmonella spp. and Listeria monocytogenes were not detected. Seventy-five strains belonged to Leuconostoc , Lactococcus , Pediococcus , Enterococcus , Lactobacillus and Weissella genera. IMPORTANCE This study provides evidence for the lack of pathogenic bacteria on the wooden shelves used to ripen internal bacterially ripened semi-hard and hard cheeses produced in Sicily. These three cheeses are non-inoculated on their surfaces and surface ripening is not considered to occur or, at least, not at the same extent of surface inoculated smear cheeses. Several bacterial groups identified from the wooden shelves are typically associated with smear cheeses strongly suggesting that PDO Pecorino Siciliano, PDO Piacentinu Ennese and Caciocavallo Palermitano cheese rind contributes to their final organoleptic profiles.
Aims The purpose of this study was to functionalize an ovine stretched cheese belonging to 'Vastedda' typology with red grape pomace powder (GPP) of Nero d’Avola cultivar and to characterize the microbiological, physicochemical, phenolic profile and sensory characteristics of the final cheeses. Methods and Results Before cheeses production, GPP was characterized for its microbiological profile, antibacterial activity and polyphenolic content. No colonies of bacteria and yeasts were detected in the GPP. GPP showed a large inhibition spectrum against spoilage and pathogenic bacteria. Three classes of polyphenolic compounds belonging to flavan‐3‐ols, flavonol and phenolic acids were identified. Two cheeses [0 and 1% (w w−1) of GPP] were produced with pasteurized ewe's milk and commercial starter cultures. Plate counts and randomly amplified polymorphic DNA analysis demonstrated the ability of the starter strains to drive the fermentation process in the presence of GPP. GPP enrichment resulted in an increase of protein, phenolic compounds, sensory traits and reduced fat. Conclusions GPP addition to cheese represents an optimal strategy for the valorization of winemaking by‐products and to obtain polyphenol‐enriched cheese. Significance and Impact of the Study This study allowed to achieve an ovine cheese with specific physicochemical, nutraceutical and sensorial characteristics able to enlarge the functional dairy product portfolio.
Pear fruits are known for their antioxidant and nutritional characteristics. However, they are very susceptible to rapid decay. Edible coating (EC) represents a good strategy to maintain postharvest quality. The effects of two EC in slowing down the senescence processes in fresh-cut ‘Coscia’ pears were investigated: EC1 (A. vera gel, hydroxypropyl-methylcellulose and pomegranate seeds oil (PSO), EC2 (A. vera gel and hydroxypropyl-methylcellulose). Weight loss, firmness and colour decrease more slowly in both EC-treated than in untreated (CTR) slices; soluble solid content increases faster in CTR, indicating a faster ripening process. The specific investigation of undesired microorganisms did not generate any colony in all analysed samples. Sensory analysis confirmed that the tasters preferred the EC2-treated samples, as they were the only ones that did not show undesirable flavours until the last day of storage.
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.
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