Probiotic Potential of Autochthone Microbiota from S&#227;o Jorge and <i>Parmigiano-Reggiano</i>Cheeses

For a long time, ripened cheeses have been officially recognized as having human health beneficial properties. However, to date only a few studies have investigated the complex microbiota of S?o Jorge and Parmigiano-Reggiano cheeses in order to identify microorganisms with probiotic potential. Hence, with the purpose of analyzing the probiotic potential of autochthone bacteria from S?o Jorge and Parmigiano-Reggiano cheeses, lactic acid bacteria isolated from both products were isolated and their direct biotic interaction against three bacteria found in the human intestine evaluated. From a total of 225 bacterial autochthone isolates, 67 had synergetic behavior with Bifidobacterium animalis , 34 had no synergetic behavior with Shigella dysenteriae and 33 had antagonistic activity with this human pathogen. Biochemical tests were used to identify these cheese isolates with probiotic potential. Lactobacillus paracasei subsp paracasei Lactobacillus arhamnosus were found in S&#227;o Jorge cheese and Lactobacillus rhamnosus , Lactobacillus buchneri and Lactobacillus curvatus in the Parmigiano cheese. Overall, initial exploratory studies with S&#227;o Jorge cheese seem to show a higher number of potential probiotic agents than those found in the Parmigiano-Reggiano cheese. However, in order to better understand the functional potential of this traditional Portuguese cheese, further confirmatory studies should be pursued.

Esterase Activities and Biochemical Properties of Lactic Acid Bacteria Isolated from Goat＇s Milk Cheese in Argentina

Twenty-two lactic acid bacteria （LAB） strains isolated from Argentinean goat dairy products were evaluated for its biochemical properties and esterase activities relevant to flavor development. Streptococcus thermophilus （UNSE314）, Lactobacillus （L.） delbrueckii subsp, bulgaricus （UNSE309）, L. rhamnosus （UNSE308）, L. plantarum （UNSE287, UNSE316, UNSE317） and Pediococcus pentosaceus （UNSE315） strains presented high acidifying activity. All strains tested metabolized citrate and produced diacetyl-acetoin in goat milk. Based on these results, 10 strains with the best performance in diverse technological properties were selected to determine esterolytic activity. In all evaluated strains, esterase specific activity （ESA） was detected on ct-naphthyl （ct-NA） acetate and 13-naphthyl （[3-NA） acetate, propionate, eaprylate and ct-NA butyrate. No activity was detected on [3-NA laurate. The highest values were detected when using a-NA instead of fI-NA derivatives as substrate. In Pediocoecus strains, wide variability in ESA were observed, which were species- and strain-specific. These results allow us to select strains with biochemical properties and esterase activities to design starter and adjunct cultures that contribute to flavor development during cheese ripening, thus preserving the typical organoleptic characteristics of Argentinean goat cheeses.

Use of <i>Pergularia tomentosa</i>Plant Enzymatic Coagulant System in Fresh Cheese-Making

Introduction: Pergularia tomentosa is a saharan spontaneous plant belonging to Asclepiadacea family. It has several medicinal properties and uses in the human food as an auxiliary in cheese-making. The purpose of this study is the extraction of the coagulant enzymatic system (C.E.S) from the plant dried leaves and its use in the preparation of fresh cheese. Materials & Methods: The determination of the coagulant activity was carried out on a skimmed milk powder by Berridge’s method. Cow’s milk used for coagulant strength determination and cheese-making. Proteolytic activity. The chemical determinations of raw milk were carried out according to AFNOR analysis methods. A descriptive sensory evaluation was performed to determine the organoleptic properties of the produced cheese. The proteolytic activity was determined by measuring the aspartyl-protease units. Results: The main results of the physico-chemical characterization show that its coagulant activity (R.U mL-1) was 97.19 ± 4.67, coagulant strength (SU) was 230.05 ± 0.37, proteolytic activity (μg·mL-1) was 0.33 ± 0.04 and coagulant activity/proteolytic activity ratio was 294.51. For the cheese made, it has presented the following results as % (g/100g): titrable acidity 0.80 ± 0.005, total dry extract 30.48 ± 1.490, fat 2.32 ± 0.02, fresh yield 11.5 ± 0.09, dry yield 30.06 ± 0.05. Moreover, sensory analysis results showed that fresh cheese prepared from Pergularia tomentosa dried leaves diluted enzymatic extract filtrate was characterized by whitish color, smooth texture, with acceptable and satisfying lactic taste. Conclusion: The plant enzymatic system studied could be added to the list of plant rennet substitutes and, thus, contributes to the manufacture of enzymatic coagulation cheese.

牦牛乳软质干酪成熟期挥发性风味成分分析

采用固相微萃取-气相色谱-质谱联用(SPME-GC-MS)对不同成熟时期(30、60、90d)牦牛乳软质干酪挥发性风味物质进行分离鉴定,共检测出45种化合物,并用峰面积归一化法确定各种化合物的相对百分含量。通过对固相微萃取纤维头和萃取温度的筛选优化实验条件,采用75μmCAR/PDMS(碳分子筛-聚二甲基硅氧烷)萃取纤维头,50℃条件下吸附不同成熟时期(30、60、90d)干酪的挥发性风味物质效果较好。检测出的挥发性风味物质主要是酸类、醇类、酮类,其次为酯类和醛类化合物,酸类物质构成了牦牛乳软质干酪的主体特征风味。乙酸、丁酸、己酸成为干酪中的优势风味物质。

干酪乳杆菌抑制大豆奶酪中的金黄色葡萄球菌和枯草芽孢杆菌

干酪乳杆菌LCR 719的培养上清液能很好抑制S.aureus和B.subtilis。在10℃下贮藏时,接入LCR 719的大豆奶酪可使S.aureus的菌数降低至原来的1/10-1/100,使B.subtilis的菌数降低至原来的1/10以下。在30℃下贮藏时,接入LCR 719的大豆奶酪可抑制S.aureus和B.subtilis的生长。结果表明,LCR 719能用作大豆奶酪生产的潜在保护性菌种。

Phenotypic and phylogenetic characterization of Lactobacillus species isolated from traditional Lighvan cheese

Lighvan cheese(Lighvan panir)is among the most famous traditional cheese in Iran for its desired aroma and flavor.Undoubtedly,the lactic acid bacteria especially the genus Lactobacillus are the critical factors in developing the aroma,flavor,and texture in Lighvan cheese.In this study,the Lactobacillus population of the main Lighvan cheese was investigated.The Lactobacillus of the main Lighvan cheese was isolated using specific culture methods according to previously published Guidelines.Then,the phylogenetic features were investigated and the phenotypic characteristics were examined using specific culture methods.Twenty-eight Gram-positive bacterial species were identified belonged to the genus Lactobacillus.According to the same sequences as each other,three groups(A,B,and C)of isolates were categorized with a high degree of similarity to L.fermentum(100%)and L.casei group(L.casei,L.paracasei,and L.rhamnosus)(99.0 to 100%).Random amplified polymorphic DNA(RAPD)fingerprint analysis manifested the presence of three clusters that were dominant in traditional Lighvan cheese.ClusterІwas divided into 4 sub-clusters.By the result of carbohydrate fermentation pattern and 16S rRNA sequencing,isolates were identified as L.rhamnosus.The isolates in clusters II and III represented L.paracasei and L.fermentum,respectively as they were identified by 16S rRNA sequencing and fermented carbohydrate patterns.Our result indicated that the specific aroma and flavor of traditional Lighvan cheese can be related to its Lactobacillus population including L.fermentum,L.casei,L.paracasei,and L.rhamnosus.

China's Big Cheeses, Mining Mess,Domestic Disorder, and Self-help

You can’t open a newspaper or turn on a TV in China without hearing about the rise of China,but,it’s easy to forget that China is a changed nation where successes aren’t simply dictated by the central authorities anymore.Today,there are any number of Chinese citizens changing the world in constructive and fascinating ways—scientists,entrepreneurs,journalists,activists,and so many more.This issue,we discuss six very special

Metagenomics and volatile profile of Turkish artisanal Tulum cheese microbiota

Turkish artisanal Tulum cheese is a traditional raw milk cheese and starter cultures are not used for ripening process.In this study,16S rRNA amplicon-based sequencing approach was used for determining bacterial diversity in Tulum cheeses.The volatile organic compound(VOC)profile which contributes to sensory properties of the cheeses was determined via solid-phase microextraction combined with gas chromatography-mass spectrometry(GC-MS/SPME)and correlated with the microbiota.In Tulum cheese samples,Lactobacillaceae(30,71%)phylum widely varied but Streptococcaceae(59,86%)was dominant.It mainly belongs to the four dominant genera of lactic acid bacteria(LAB)and includes Lactobacillus,Lactococcus,Streptococcus and Pediococcus.The bacterial diversity of TC5 sample was much higher than that of other samples.Moreover,several species of non-starter LAB were frequently detected.A total of 36 volatile compounds were identified including hydrocarbons(3),acids(13),alcohols(5),ketones(3),aldehydes(3),esters(8)and miscellaneous compound(1).Pentadecanoic acid,octadecanoic acid,tetradecanoic acid,octanoic acid,hexanoic acid were determined to be dominant in all cheese samples and to be related to microbial flora.Also,the sensory profiles of the samples were examined.The most popular TC6 did not contain 2-butanone and hexanal from the volatile organic compound(VOC)values,while in the most unpopular TC3,2-butanone(7.73%)and hexanal(5.95%)were found to be the highest.The outcome of this study will contribute to literature on bacterial diversity and aromatic profile of Tulum cheese which should be investigated in order to improve quality and safety.